Datasets:

AlvianKhairi

/

my-pandas-dataset-Abstract_No_Link_270k

like 0

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Amino-acid composition of the covalent rigid-layer lipoprotein in cell walls of Proteus mirabilis.? [/INST] Cell walls of Proteus mirabilis in the stationary phase of growth contain a lipoprotein in covalent linkage to peptidoglycan and probably also in free form in the outer membrane. The protein moiety of this lipoprotein is composed of about 50 amino acids and has an approximate molecular weight of 5500. The Proteus lipoprotein has glycine and phenylalanine as specific components which are not present in lipoproteins of other enteric bacteria. Treatment of the peptidoglycan-lipoprotein complex of Proteus with trypsin leaves lysine as the only lipoprotein amino acid attached to the peptidoglycan. This suggests that in P. mirabilis, as in Escherichia coli, the lipoprotein is linked to the peptidoglycan by its C-terminal lysine residue. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The interaction of fusidic acid with peptidyl-transfer-ribonucleic-acid - ribosome complexes.? [/INST] The inhibitory action of fusidic acid on peptide-chain elongation was studied with systems in vitro directed by either polyuridylic acid or endogenous messenger (Escherichia coli polysomes washed with 1 M NH4Cl) or R17 RNA, and supplemented with either crude or purified elongation factors. In all cases strong inhibition of synthesis required high concentrations of the antibiotic (approx. 1 mM), while a similar inhibition of the EF-G-plus-ribosome-dependent GTP hydrolysis required between 10 and 100 times less antibiotic. Since most of the GTP hydrolysis observed was presumably due to free ribosomes (without aminoacyl-tRNA or peptidyl-tRNA), fusidic acid seemed to interact far more easily with these ribosomes than with ribosomes engaged in peptide-chain elongation. The role of the GDP-EF-G-ribosome-fusidic acid complex in the inhibition of polypeptide synthesis was assessed by measuring formation of this complex on polysomes engaged in peptide-chain elongation. Using purified elongation factors the complex formed on only 25-35% of ribosomes, as measured either by retention of [3H]GDP or by hydrolysis of [3H, gamma-32P]GTP. In contrast, with crude factors (S 100 extract) it formed on more than 70% of ribosomes. The results are compatible with the postulated role of the complex in polypeptide synthesis inhibition (blockade of the ribosomal acceptor site and subsequent inhibition of aminoacyl-tRNA binding) and indicate that formation of the complex takes place by overriding the control that prevents interaction of EF-G when the donor site is occupied by peptidyl-tRNA. In the polyuridylic-acid-directed system for synthesis of oligophenylalanine the antibiotic inhibits every round of peptide elongation, including dipeptide formation, to roughly the same extent. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The joining of the 30-S initiation complex with the 50-S subunit, the main target for thiostrepton.? [/INST] The study undertaken in this paper on the mode of action of thiostrepton provides data which permit a more precise localization of the main target of thiostrepton. There is severe impairment of the joining of the 50-S subunit, probably carrying thiostrepton, with either the 30-S subunit or the 30-S initiation complex. The degree of impairment of this coupling is temperature dependent, being almost completely inhibited at 0 degrees C, whereas at 37 degrees C the effect is much less marked, provided that natural messenger RNA is present. The inhibition of initiation by thiostrepton is more severe in the presence of IF-1, a factor, which similar to thiostrepton, is able to shift the dynamic equilibrium of 70-S in equilibrium 50-S + 30-S more towards dissociation. By means of 14C-labeled IF-2 it is demonstrated that the binding of IF-2 into the 70-S initiation complex is prevented by thiostrepton, which seems to be the main cause for non-coupling. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Preferential digestion of (A plus T)-rich stretches of yeast mitochondrial DNA in isolated mitochondria.? [/INST] Yeast mitochondrial DNA labelled in vitro by incubation of isolated mitochondria with DNA precursors exhibits skewed profiles on isopycnic CsCl gradients. The skew is not due to nuclear DNA nor to single-stranded mitochondrial DNA in the product labelled in vitro. Simultaneous labelling with [3H]dTTP and [14C]dGTP in vitro indicates a gradient of base composition in the DNA labelled in vitro. Thus, selective degradation of mitochondrial DNA occurs during incubation, converting large molecules having the mean density of mitochondrial DNA into smaller molecules of higher mean density and with higher G:T ratio. Similarly skewed distributions can also be produced by incubation of mitochondrial DNA labelled in vivo with the yeast mitochondrial fraction or with micrococcal endonuclease, an enzyme known to selectively hydrolyse (A plus T)-rich regions of DNA. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Interaction of RNA polymerase from Escherichia coli with DNA. Analysis of T7 DNA early-promoter sites.? [/INST] A method was devised for directing RNA polymerase on a single promoter site on T7 DNA. Initiation complexes were formed on each of the three main promoter sites using one dinucleotide plus one nucleoside triphosphate. The ternary initiation complexes are resistant to rifampicin action, to inhibition by (rI)n at 0 degrees C and are stable at high salt concentrations. A minimum of a trinucleotide is required to form a stable ternary complex. To determine which promoter site was selected by RNA polymerase during initiation, the (rI)n-resistant RNA was digested by RNAse III to generate three characteristic initiator RNA fragments, resolved by gel electrophoresis. The three major promoter sites could be selected individually by using different primer and substrate combinations ApC plus ATP selected promoter A3, CpG plus CTP selected A2 and CpC plus ATP specified preferentially A1. A number of primer-substrate combinations specified each site at low salt concentration but the substrate requirement became very stringent at high salt concentration, suggesting that the postulated local opening of the promoter site could be more or less extensive, depending on the ionic strength. The minimum opening observed at high salt concentration corresponded to the insertion of a leader trinucleotide sequence. The promoter region melted by RNA polymerase at low salt concentration was (G plus C)-rich and corresponded to about 9 to 11 base pairs. Sequences of the melting recognition regions were tentatively inferred from the results. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The methylation of mercuric chloride by human intestinal bacteria.? [/INST] Most strains of staphylococci, streptococci, yeasts and E. coli isolated from human faeces, could synthesize methylmercury compounds. In contrast, few strains of obligate anaerobes could do so. Up to 6 ng methylmercury/ml were formed in 44 h from 2 mug mercuric chloride. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Erythrocyte agglutinins in the blood of certain ascidians.? [/INST] Plasma from Ciona intestinalis, Phallusia mamillata and Ascidia malaca possess hemagglutinin for a variety of erythrocytes. Results obtained by physical and chemical treatments suggest that hemagglutinin for Phallusia mamillata and Ascidia malaca may be a protein or a protein-like substance. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of intracisternal insulin on plasma glucose and insulin in the dog.? [/INST] The intracisternal administration of insulin (0.2 U./kg.) to anesthetized dogs resulted in an increase of arterial immunoreactive insulin and a decrease of plasma glucose relative to a control injection. The arterial responses were significantly attenuated when the insulin was administered to the cisternum of subdiaphragmatically vagotomized dogs. When cerebrospinal fluid glucose was lowered by injecting pneumococcal neuraminidase intracisternally, no peripheral hyperinsulinemia resulted, indicating that increased spinal fluid insulin and its consequent increase of glucose uptake, rather than decreased spinal fluid glucose, is necessary to elicit the vagally mediated insulin secretion and hypoglycemia. It is hypothesized that increased spinal fluid insulin causes an increased glucose uptake of some glucoregulatory area of the brain and that the elicited reflex is vagally mediated pancreatic insulin secretion. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Dynamics of insulin release and microtubular-microfilamentous system. VII. Do microfilaments provide the motive force for the translocation and extrusion of beta granules?? [/INST] The active role played by beta-cell microfilamentous structures in the dynamics of insulin secretion was investigated by examining the influence of cytochalasin B upon various parameters of hormonal release by the isolated perfused rat pancreas. The view that the cytochalasin-induced changes in insulin release are due to a primary biophysical effect on microfilaments, rather than to an unrelated biochemical alteration of the beta-cell glucose-sensor device, was strengthened by the following observations: (1) the onset and disappearance of the cytochalasin B-induced facilitating action upon insulin release followed a time-course parallel to that characterizing the ultrastructural changes provoked by the drug in the distribution of beta-cell microfilamentous material; and (2) cytochalasin B facilitated leucine-induced insulin release in the presence of a very low glucose concentration. The mold metabolite was also found to transform transient secretory responses into biphasic ones and to prevent the reduction that normally affects the early response to insulinotropic agents when the pancreas is stimulated a few minutes after a prior and short exposure to glucose. The release of insulin evoked by either glucose or gliclazide was abolished in the absence of extracellular calcium, whether in the presence or absence of cytochalasin B. Theophylline and cytochalasin B exerted a synergistic effect upon glucose-induced insulin release. These data support the concept that calcium-dependent contractile events involving cytochalasin B-sensitive microfilamentous structures provide the motive force for both the intracellular translocation and exocytotic release of beta granules. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of cerebral intraventricular insulin on pancreatic insulin secretion in the dog.? [/INST] The effect of cerebral intraventricular insulin on pancreatic insulin secretion was investigated. An extracorporeal pancreatic blood circuit was established after laparotomy to monitor blood flow and insulin concentration directly from the superior pancreaticoduodenal vein. Phentolamine was infused throughout (0.2 mg./min. intravenously) to block alpha-adrenergic effects of any catecholamine secretion induced by surgical stress. Glucose (1.5 mg./kg./min. intravenously) was infused to maintain a constant baseline stimulation of insulin secretion. Six dogs received insulin and six control dogs received saline through a spinal needle stereotaxically placed into the left lateral cerebral ventricle. After central injection of insulin (0.2 U./kg.) there was a significant increase of pancreatic output as early as five minutes. It is concluded that the pancreatic beta-cells are under the influence of insulin-sensitive cells of the CNS. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Ethanol-induced alterations of glucose tolerance, postglucose hypoglycemia, and insulin secretion in normal, obese, and diabetic subjects.? [/INST] Ethanol at an average blood concentration of 1 mg. per milliliter enhanced the immediate (first-phase) and prolonged (second-phase) insulin response to an intravenous glucose load in nonfasting normal human subjects. Simultaneously, the glucose disposal rate was increased and the postglucose hypoglycemia was accentuated, resulting in definite hypoglycemic symptoms in some individuals. Oral glucose tolerance was not changed by ethanol administration, but the thirty-minute blood glucose and plasma insulin values were increased, suggesting that alcohol might accelerate the absorption of glucose from the gut. Ethanol given orally during evening hours (1.5 gm. per kilogram) caused a nocturnal hyperinsulinemia and a decrease of blood glucose, but not an actual hypoglycemia. Oral glucose tolerance and plasma insulin response tested the next morning, when ethanol had disappeared from the blood, were not influenced by drinking the previous evening. The K-value of intravenous glucose was increased at this time, however. When alcohol was administered for one week at a dose corresponding to 25 per cent of daily calories and substituting for fat, both the oral and intravenous glucose tolerances were impaired in each subject but the insulin response remained unchaged. In obese nondiabetic subjects, ethanol did not potentiate the early insulin response to intravenous glucose but it increased the second phase of insulin secretion in response to sustained hyperglycemia. In contrast to conditions in nonobese subjects, the glucose disposal rate was not incresed and postglucose hypoglycemia was not accentuated by ethanol in overweight subjects. In insulin-deficient diabetic patients the absent early insulin response could not be restored by ethanol, and the late component of insulin release was little increased by alcohol infusion. Ethanol did not improve the glucose utilization of diabetic patients. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The G cell population of the pyloric antrum of the cat.? [/INST] The method used in this study to quantify the G cell population of the cat is similar to the technique used for measuring the parietal cell mass in the stomach of rats and man. The method may be used on the human antrum. Mucosal sampling technique and immunofluorescence methods are described. The method is reproducible. G cell distribution in the antrum was not uniform and the highest concentrations were found along the lesser curvature. The G cell population was 10.27, 12.66, 12.87, 12.88 and 15.42 million cells (mean 12.8 x 10(6)) per antrum in each of the five cats studied. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The autonomic nervous system and its relationship to tubal ovum transport--a reappraisal.? [/INST] The role of the autonomic nervous system in controlling ovum transport remains obscure. Although not studied extensively in the oviduct, the para-sympathetic nervous system does not appear to significantly influence ovum transport. The sympathetic nervous system of the oviduct and its pharmacology have been studied more thoroughly. Despite this, little information is available concerning cellular mechanisims of adrenergically altered motility or transport. In spite of much speculation, the weight of evidence suggests that, at least in the rabbit, the sympathetic nervous system plays a minor role in the control of ovum transport. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Sperm transport to and survival in the human fallopian tube.? [/INST] A review is given on sperm migration to and sperm survival within the human Fallopian tube. Sperm migration from the external os can be very fast. The survival time of spermatozoa in the oviduct has been demonstrated to be 85 h. Spermatozoa normally enter the abdominal cavity through the open fimbriated end. Laterally closed oviducts retain spermatozoa resulting in a larger number of spermatozoa than in the normal oviduct, where the number of sperm at the site of fertilization is very low. The morphology of spermatozoa reaching the ampulla of the oviduct is mostly normal, which seems to be based on the correlation between normal morphology and good motility. Spermatozoa within the abdominal cavity do not cause antibody formation of any importance for the fertility of the woman. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The isolation of protoplasts of the fission yeast Schizosaccharomyces by Trichoderma viride and snail enzymes.? [/INST] The formation of protoplasts of the fission yeasts Schizosaccharomyces pombe and Schizosaccharomyces versatilis after the combined application of snail enzymes and Trichoderma viride enzymes in an osmotic stabilizer (0.4M KCl, pH 5.5) was studied by light and electron microscopy. The effect of the enzymes used leads during 30 min to the formation of 100% protoplast population. Using electron microscopy no original walls or wall remnants were detected in the suspension of protoplasts. Protoplasts are viable and in liquid nutrient medium they regenerate cell walls and revert into normal cells. Such a protoplast population may be useful for biochemical study of protoplast metabolism by quantitative methods as well as for the chemical study of regenerating cell walls. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Penicillinamidohydrolase in Escherichia coli. II. Synthesis of the enzyme, kinetics and specificity of its induction and the effect of O2.? [/INST] The differential rate of synthesis of penicillinamidohydrolase (penicillin acylase -- EC 3.5.1.11) was studied in Escherichia coli growing in some chemically defined media and in a complex medium. The enzyme is synthesized at a constant rate only during the exponential phase of growth of cells. Its synthesis is induced most effectively (with respect to quantity) by phenylacetic acid. The induction lag of the enzyme synthesis in a medium with acetate corresponds to two generation times. The highest rate of the enzyme synthesis is reached in a medium containing phenylacetic acid as the only source of carbon and energy. The enzyme synthesis is fully repressed by an increased concentration of dissolved oxygen in the medium, even when Escherichia coli is cultivated in the medium with phenylacetic acid as the only carbon and energy source. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effect of medium composition on the production of valine by Corynebacterium 9366 - EMS/184.? [/INST] The auxotrophic mutant Corynebacterium 9366-EMS/184, requiring isoleucine accumulates about 22 g of L-valine per litre after a 96 h cultivation in a medium containing 15% sucrose and 1% ammonium acetate. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Formation of a complex between yeast proteinases A and B.? [/INST] Sephadex G-100 gel filtration of a purified mixture of tryptophan-synthase-inactivating enzymes I and II from Saccharomyces cerevisiae, which had previously been identified as yeast proteinases A and B, yields two coincident peaks of tryptophan-synthase-inactivating activity and proteinase A and B activities. The peaks correspond to molecular weights of approximately 100 000 and 50 000. It could be demonstrated, with purified proteinases A and B, that the high molecular weight peaks is due to the formation of a stoichiometric complex between proteinases A and B. The AB complex can easily be separated into its constituent enzymes by DEAE-Sephadex chromatography. When in the AB complex, proteinase B molecules still bind the specific proteinase B inhibitor from yeast. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Synthesis of a chemically reactive analog of the nonsense codon U-G-A. Its reaction with ribosomes of Escherichia coli.? [/INST] Nitrophenylated 5'-uridylic acid could be employed as primer in a polyribonucleotide nucleotidyltransferase (Micrococcus luteus) reaction to yield 5'-nitrophenylated Pu-G-A. After reduction of the nitrophenyl moiety and subsequent bromoacetylation, a 5'-bromoacetamido-phenyl-phosphorylated U-G-A was obtained, which could be used as an affinity label for the ribosomal binding site of the nonsense codon. If freshly prepared active ribosomes were employed in the incubation mixtures, the U-G-A analog reacted exclusively with one protein, which is tentatively identified as protein S18. Exposure of ribosomes to low temperatures gave rise to a reaction of the U-G-A label with another protein, which was identified as protein S4, the ram gene product. The results of the affinity labeling experiments with the chemically reactive U-G-A derivative are very similar to that obtained with a corresponding derivative of the initiation codon A-U-G (O. Pongs and E. Lanka (1975) Proc. Natl. Acad. Sci. U.S.A. 75, 1505-1509), which suggests that 70S ribosomes have one preferential codon binding site. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The primary structure of the 5s rRNA binding protein L25 of Escherichia coli ribosomes.? [/INST] The primary structure of protein L25 from the large subunit of Escherichia coli ribosomes was determined by isolation and analysis of peptides obtained after cleavage of the protein with trypsin, thermolysin and Staphylococcus protease as well as by Edman degradation of the intact protein and of a CNBr peptide. The complete amino acid sequence is shown in Fig. 4. There are sequence homologies within protein L25 (Table 6) as well as between protein L25 and other ribosomal proteins (Table 5). </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Properties of Isoaccepting tRNALys, tRNAGlu and tRNAGln from rabbit Reticulocytes and liver. Multiplicity, Codon Recognition and Inactivation by Iodine.? [/INST] The three tRNA species from rabbit liver and reticulocytes, each corresponding to the codons XAA and XAG(X equals A, G, C) were investigated. The elution patterns of the isoaccepting tRNA subspecies after separation by reversedphase chromatography followed by determination of amino acid acceptance have common and differing characteristics. Three subspecies of tRNALys, two of tRNAGlu and three of tRNAGln have been found in reticulocytes, wheras two subspecies of tRNALys, three of tRNAGlu and four of tRNAGln have been determined in rabbit liver. Examination of codon recognition by means of a ribosome binding assay showed that each subspecies binds exclusively in the presence of only one of the two possible triplets; i.e. wobbling was not found. It has been assumed that this high specificity, which is not to be expected according to the "wobble hypothesis", is due to a 2-thiouracil base in the first position of the anticodon. This was supported by oxidation experiments with iodine. Treatment with iodine significantly reduces the aminoacylation capacity of all subspecies that show specific binding with triplets ending in adenosine. We describe and compare for the first time the characteristics of eucaryotic tRNA species which occupy homologous positions in the codon table. Thus it can be seen that all the investigated subspecies have rigorously specific codon recognition in common, wherby "wobbling" can probably be excluded by a principle that is valid for all the investigated species. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about B-chain shortening of matrix-bound insulin with pepsin, II. Preparation and properties of camel des-pentapeptide (B26-30)- and des-PheB1-des-pentapeptide (B26-30)- insulin.? [/INST] Digestion of matrix-bound camel insulin with pepsin was found to be restricted to the cleavage of the peptide bond between phenylalanine(B25) and tyrosine(B26). Purification of the camel des-pentapeptide(B26-30)-insulin obtained was achieved by gel filtration and ion exchange chromatography, yielding a molecularly uniform product. In the same way, camel des-PheB1-insulin prepared according to a method described for bovine insulin was hydrolyzed with pepsin and purified to give the des-PheB1-despentapeptide(B26-30)-insulin. The biological activity of these modified camel insulins was found to be as much reduced as the corresponding bovine insulin analogues. However, the reduced biological activity of camel des-PheB1-insulin (60%) was a contrast to the fully active bovine des-PheB1-insulin. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Pathology of cerebral embolization caused by nonthrombotic agents.? [/INST] Although apparently infrequent, a variety of agents other than thrombotic material are known to cause cerebral embolization, often with serious consequences. The emboli may originate in different parts of the body or may be introduced from outside under diverse circumstances. The pathologic aspects of these individual embolic phenomena are described with particular emphasis on their recognition at autopsy. Adequate autopsy study appears to be the most important source of information for further elucidation of the incidence, mechanism, and sequelae of these heterogeneous embolic lesions of the brain. Such information is essential for clinical evaluation, management, and, more importantly, prevention of some of these potentially serious embolic phenomena. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Vascular structures in brain tumors.? [/INST] The blood vessels within brain tumors show alterations from the normal anatomy. Some of these seem to be related to an increased capacity to transfer materials between the lumen and the parenchyma and are probably intimately connected with the edema associated with the tumor. These alterations include fenestration, widened intercellular junctions, increase in pinocytotic vesicles, and infolding of the luminal surface. Other alterations are observed but their function is not as clear. The latter include an increase in the number of tubular bodies, the appearance of tubular structures within vacuoles, tubular arrays within the nuclear envelope and rough endoplasmic reticulum, and endothelial proliferation, among others. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Distribution of cytophilic and anti-macrophage antibody on the macrophage surface.? [/INST] The binding of cytophilic antibody to the macrophage surface results in patterns of distribution similar to those obtained when specific anti-macrophage antibody is used. These patterns are (a) diffuse circumferential binding at 4 degrees C, and (b) capping at 37 degrees C. The non-random distribution of the cytophilic antibody suggests that it binds to certain well-defined sites on the macrophage membrane. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Endocytosis of chlorambucil-bound anti-tumor globulin following "capping" in EL4 lymphoma cells.? [/INST] A rabbit 7 S antibody reacting specifically with a tumor assoicated antigen on the surface of mouse EL4 lymphoma cells could form "caps" and subsequently undergo endocytosis even when the antibody was non-covalently bound to chlorambucil. As the alkylation of nuclear DNA appears to be the basis of tumor inhibition by alkylating agents like chlorambucil, facilitation of the transport of chlorambucil across cell membrane by anti-tumor antibodies might explain, at least in part, the increased tumor inhibition by cholorambucil bound anti-tumor antibodies compared to tumor inhibition by equivalent amounts of tumor antibodies or chlorambucil alone. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Experimental murine leprosy: growth of Mycobacterium lepraemurium in C3H and C57/BL mice after footpad inoculation.? [/INST] Forty-three female C57/BL and C3H mice were inoculated with 2.7 X 10(6) Mycobacterium lepraemurium into each hind footpad. The foot thickness and the number of acid-fast bacilli in the footpad and popliteal and inquinal lymph nodes were recorded. In addition the morphological index and the mean bacillary length were determined in the footpad and in the popliteal lymph node. The bacilli multiplied in both strains during the first 4 weeks after inoculation. After that time no further increase in acid-fast bacilli was observed in the C57/BL strain; the bacilli became elongated and the morphological index decreased. These changes were preceded by a local swelling of the footpad due to the onset of an immune reaction. Thus, under the present conditions, C57/BL mice were able to resist experimental infection with M. lepraemurium by developing an immune response. In C3H mice no indication of an immune reaction was detected, and the bacilli continued to multiply throughout the observation period. The mouse footpad model seems to provide an excellent basis for the use of experimental murine leprosy to study immunity to mycobacterial infections. Certain aspects of the present model are discussed in relation to the mouse footpad model as used in the study of M. leprae infection in mice. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Induction of the immune response to cell surface antigens in vitro.? [/INST] Two tissue culture incubation systems are described in which immune responses to cell surface antigens have been demonstrated. In the one-way "mixed lymphocyte interaction" system, a specific stimulation of thymidine uptake was induced by a particulate membrane antigen fraction, the microsomal lipoproteins (MLP), when low levels (0.01 to 0.001 mug per ml) were incubated with spleen or lymph node cells from nonsensitized mice. No stimulation was seen when allogeneic MLP was used at high levels, 10 mug per ml, nor at any level with syngeneic MLP. Specific effectors were demonstrated after 72-hr incubation with stimulatory levels of allogeneic MLP in three separate in vitro assays, a plaque-forming cell reduction assay, a tumor target assay, and an antigen-binding cell assay. In the latter assay, [125I]MLP was used as the source of antigen. This system has limited potential inasmuch as mouse spleen cells do not survive in it beyond the 4th day of culture. The second tissue culture system, the Marbrook system, has much greater possibilities because at least 25% of the inoculum is recovered 7 days later. In this culture system a cell-free sheep erythrocyte membrane preparation can induce plaque-forming cells in the absence of macrophages. Using a sensitive radioimmunoassay, free specific antibody was detected in culture supernatant fluids. With the same culture system, allogeneic lymphocytotoxic cells (killer) have been induced with spleen cells from unprimed mice in strains differing at the major histocompatibility locus (H-2). Allogeneic MLP induced very significant "killer" cell activity with spleen cells from primed mice. In a syngeneic tumor system, significant amounts of killer cell activity were induced with unprimed spleen cell inocula, and much larger amounts induced with spleen cells from immunized mice. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Comparison of leukocyte count and function in smoking and nonsmoking young men.? [/INST] Leukocyte function and other hematological measurements were tested in 14 smoking and 13 nonsmoking young men free of intercurrent or chronic diseases. Leukocyte chemotaxis was depressed in smoking subjects when compared to the same subjects abstaining from cigarettes or to the nonsmokers. Smoking did not affect the whole blood bactericidal capacity of leukocytes and serum for Staphyloccus aureus or Klebsiella pneumoniae. Total leukocyte counts, hematocritis, and monocyte counts were higher in the smoking subjects when compared to the nonsmokers. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Klebsiella pneumoniae and Staphylococcus aureus infection in mice: difference in uremia and ammoniagenesis.? [/INST] Lethal infections by Staphylococcus aureus and Klebsiella pneumoniae were compared for kidney-related effects in mice. K. pneumoniae caused uremia and an increase in blood ammonia that could reach 2.5 times normal. These events did not occur in mice inoculated with S. aureus. Use of germfree animals indicated that most of the increase in ammonia arose from the gut, presumably due to greater availability of urea and ureolysis. Injected ornithine restored blood ammonia to nearly normal levels and extended survival. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Model system for studying colonization and growth of bacteria on a hydroxyapatite surface.? [/INST] A model system for the study of bacterial colonization and growth on a hydroxyapatite (HT) surface is described. Hydroxyapatite was crystallized over the surface of porous glass beads. Chemical analysis of the product showed that the ratio of Ca2+/P042- was indistinguishable from that of commercial HT powder. X-ray diffraction analysis supported the conclusion that the product was HT. A system employing [14C]polyethylene glycol, which selectively adsorbs to the glass surface of the beads, was developed to determine the amount of glass surface covered by HT. Over 90% of the glass surface could be covered by our method. The product, HT beads, consisted of approximately 20% (dry weight) HT. The HT beads possess several properties which make them potentially useful for studying microbial adherence, growth, and interactions. These include: (i) chemical similarity to the tooth surface, (ii) large surface area, and (iii) high density. We also describe a method for direct measurement of the microbial mass of cells growing on beads. The method entails immobilizing a sample on a membrane filter (Millipore), staining it with amido black dye, and eluting the dye for spectrophotometric measurement. Streptococcus mutans served as the test organism. For free-growing bacteria the values measured with the filter assay were directly proportional to cell number, with a value of 1 mug of "protein" corresponding to about 1.5 X 10(6) colony-forming units, determined by viable count. For bacteria colonizing the beads, 1 mug of protein corresponded to about 2 X 10(7) colony-forming units on the beads during logarithmic growth. As the culture approached stationary phase, the efficiency of the assay decreased. These data indicate that multiple random samples, taken at a given time, are representative of the entire culture. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Hepatitis B antigens in serum and liver of chimpanzees acutely infected with hepatitis B virus.? [/INST] We report the temporal patterns of various immunohistological and serological parameters of acute self-limited hepatitis B virus infection of two chimpanzees, and we provide evidence that the synthesis of hepatitis B core antigen precedes that of hepatitis B surface antigen. Our data suggest that existence of a biphasic hepatitis B virus infection involving a hematogenous reinfection of the liver and indicate that recruitment of liver cells to produce hepatitis B virus may occur in a pattern consistent with a replicative cycle of about 8 days. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Plasmid-controlled colonization factor associated with virulence in Esherichia coli enterotoxigenic for humans.? [/INST] An enterotoxin-producing strain of Escherichia coli isolated from a case of cholera-like diarrhea (E. coli strain H-10407) was found to possess a surface-associated colonization factor. Colonization was manifested as the ability of small inocula (10(5) bacteria) to attain large (10(9)) populations in the infant rabbit intestine with a concomitant diarrheal response. A laboratory-passed derivative of E. coli H-10407, designated H-10407-P, failed to exhibit an increase in population in the infant rabbit and also failed to induce diarrhea. Cell-free culture supernatant fluids of E. coli H-10407 and H-10407-P produced equivalent enterotoxic responses in infant and in adult rabbits. Specific anti-colonization factor antiserum was produced by adsorbing hyperimmune anti-H-10407 serum with both heat-killed and living cells E. coli H-10407-P. This specific adsorbed serum protected infant rabbits from challenge with living E. coli H-10407 although the serum did not possess bactericidal activity. The anti-colonization factor serum did not agglutinate a strain of E. coli K-12 possessing the K88 colonization factor peculiar to E. coli enterotoxigenic for swine. By electron microscopy it was demonstrated that E. coli H-10407, but not H10407-, possessed pilus-like surface structures which agglutinated with the specific adsorbed (anti-colonization factor) antiserum. E. coli H-10407 possessed three species of plasmid deoxyribonucleic acid, measuring 60 X 10(6), 42 X 10(6), and 3.7 X 10(6) daltons, respectively. E. coli H-10407-P possessed only the 42 X 10(6)- and the 3.7 X 10(6)-dalton plasmid species. Spontaneous loss of the specific H-10407 surface-associated antigen was accompanied by loss of the 60 X 10(6)-dalton species of plasmid deoxyribonucleic acid and loss of colonizing ability. Thus, it is concluded that the E. coli colonization factor described here is a virulence factor which may play an important and possibly essential role in naturally occurring E. coli enterotoxic diarrhea in man. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Amount and avidity of antibody to Escherichia coli O antigen measured with the ammonium sulphate precipitation technique in children with urinary tract infections.? [/INST] The antibody amounts and avidities were analyzed in 13 patients with acute primary pyelonephritis, 11 patients with acute primary cystitis, and one with ureterocele and recurrent infections, using the ammonium sulphate precipitation (ASP) technique. The ASP titrations did not discriminate as well between pyelonephritis and cystitis as do the determinations with the indirect hemagglutination technique. The increase of antibody titer and avidity detected by the ASP method in some of the cystitis patients suggested a deeper tissue involvement in some cases resulting in antibodies demonstrable with this technique. Since control patients also showed a somewhat heterogenous antibody response regarding titer and avidity it cannot be excluded that stimulation by Escherichia coli antigens in the gut is detected by the ASP method. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Immunoglobulin-bearing lymphocytes: their demonstration in adult sheep and ontogeny in the sheep fetus.? [/INST] A method for the preparation of lymphocytes from sheep blood is described. Lymphocytes from adult and fetal sheep have been examined by immunofluorescence for surface immunoglobulin (sIg) determinants. Young adults (1.5 years) had a mean of 23.2% sIg cells, older adults (8.75 years) a mean of 9.7% sIg cells. Pregnancy did not influence these values. The earliest lymphocytes with sIg in fetal lambs were demonstrable at 52 days (96 mm crown-rump length) and countable by 56 days (110 mm CRL) at 0.3% sIg. The percentage rose rapidly to 15.1% between 78 and 87 days, followed by a fall to 2.1% around 117 days with a second increase thereafter. The significance of this spontaneous appearance of fetal sIg cells is discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [A system to aid decision-making. Application to automatic interpretation of vectorcardiograms].? [/INST] This paper presents a complete and autonomous system for the automated diagnosis (heuristic approach). The system was worked out by means of a small computer. A flexible, evolutive, quasi-universal system is achieved through original procedures. A specialised language enables the users to describe diagnoses and their criteria in symbolic form. A suitable compiler translates this symbolic writing into an interpretable object program. This, with the Interpreter program, constitutes the 'Automated Diagnosis Program'. Our data are vectorcardiograms recorded according to the Frank orthogonal system. After an interactive pre-processing process, 180 parameters--mostly spatial--are computed. The data, the computed parameters and additional information are stored in a data bank. Finally, the medical interpretation is automatically selected from 125 possibilities. The user could also utilise a data bank interrogation language. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Attitudes toward alcohol and drug use and abuse. I. Demographic and correlational data.? [/INST] Research concerning drug- and alcohol-related attitudes was reviewed. Demographic variables were not generally consistently related to attitudes. Most personality variables were also not consistently correlated with attitudes. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Chronic cerebral effects of alcohol and drug abuse.? [/INST] A minority of alcohol abusers develop severe cerebral dysfunction in the form of Wernicke-Korsakoff syndrome. There is also evidence to suggest that cerebral dysfunction, particularly impaired abstracting ability, occurs in that larger population of heavy drinkers who do not go on to develop the Wernicke-Korsakoff syndrome. There is no consistent evidence that long-term marijuana, hallucinogen, or sedative use causes lasting neuropsychological disturbance. The deficits in abstract thinking reported by some LSD studies are similar to deficits others have reported among alcoholics. Since the LSD studies were not controlled for alcohol use, their interpretation is difficult. It appears that cerebrovascular accidents occur more frequently and at a younger age among amphetamine abusers. There is no reliable information about possible other long-term effects of stimulants on the brain per se (i.e., nonvascular complications). Abuse of intravenous narcotics has been associated with case reports of transverse myelitis and encephalitis. It is not known whether this pathology is a direct or hypersensitivity effect of narcotic drugs, of adulterants, or of infection. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Methods of assessing gingival and periodontal disease: a review.? [/INST] There has been an effort by the dental profession working in the field of gingival and periodontal disease to find a method of recording the extent and degree of pathological change in tissues leading from gingivitis to periodontitis and to measure reversible as well as irreversible changes. It is obvious that some form of index is required and it should have the following well-defined criteria: (1) Simplicity, (2) Accuracy, (3) Quantitativeness, (4) Reproducibility, (5) Speed, (6) Objectivity, and (7) Amenability to statistical analysis. Indices, as well as determining the prevalence of disease in the group under investigation at a given period in time, must also provide information on incidence of disease, i.e. at different periods of time. Indices must also give data that make it possible to verify the nature, severity and aetiology of the disease process and to evaluate therapeutic measures. Indices yield information about the success or failure of control and prevention of disease, affecting the gingivae and the periodontal tissues. A review of methods of assessing and recording gingival and periodontal disease is presented starting from the early investigations of the century. It is shown that subsequently many variations evolved, often with the same inherent difficulties of interpretation or application. Usually the initial stages of inflammation of the gingivae are more difficult to recognize than established disease. Present methods of recording as objectively and as quickly as possible the gingival state in population groups are discussed with emphasis upon the necessity for providing effective preventive measures based upon assessment of schoolchildren. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Enzyme cytochemistry of blood and marrow cells.? [/INST] Diseases of the blood and bone marrow are commonly associated with abnormalities of oxido-reductase and lysosomal enzymes within individual erythrocytes and leucocytes. There are considerable technical difficulties, however, in adapting enzyme histochemical techniques to the study of haemopoietic tissue since individual cells are readily disrupted during processing, show variable enzyme activity according to the stage of maturation, and possess a lipoprotein cytoplasmic membrane which hinders reagent penetration. Cytochemical techniques for the study of oxido-reductase systems are of importance in the study of the neutrophil in infected patients, the erythrocyte in glucose-6-phosphate dehydrogenase deficiency, and the primitive blast cell in acute leukaemia. Lysosomal enzymes are of importance in the study of the neutrophil in infected patients and in the differential diagnosis of acute leukaemia. Some examples of recent studies of these enzyme systems are given to illustrate technical procedures involving cytocentrifugation of cells on to glass slides, adjustment of the osmolality of the reaction mixture, and the study of smeared cells as opposed to cells incubated in suspension. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Postnatal development of pyrogenic sensitivity in guinea pigs.? [/INST] Despite evidence of thermoregulatory ability from birth, neonates generally are unable to develop fever when challenged with endotoxin. This could be due to their small capacity for heat storage. To test this possibility, the pyrogenicity of S. enteritidis endotoxin (2 mug/kg, iv) was measured at both room (Ta = 25 degrees C) and neutral (Tn = 29-33 degrees C, depending on age) temperatures in 0- to 32-day-old unanesthetized guinea pigs, reared from birth at about 24 degrees C. Control guinea pigs received sterile saline injections in concurrent experiments. Shivering, O2 uptake, and colonic (Tre) and subcutaneous [over the interscapular fat pad (Tbat) and the sacrospinalis muscle (Tsc)] temperatures were recorded continuously for 4 h after injection. Endotoxin generally produced no febrile responses at both ambient temperaturess rises in animals aged 8 or more days; Tbat increased before the other sites in the 8- and 16-day-old animals, and shivering did not occur; by 32 days of age, however, Tbat no longer increased first, and there was shivering. In Tn significant febrile rises were not evident until 32 days of age; control temperatures, however, were elevated during this exposure as compared to at Ta. These results showed therefore that pyrogenic sensitivity is not apparent in guinea pigs during the first postnatal week; thereafter fever responses are evocable, but their detection may be masked by environmentally produced changes in body temperature. The data also indicated that the site of the heat production underlying, in part, endotoxic fevers gradually shifts from brown fat so skeletal muscle during the first month of life. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Stability in lobar ventilation distribution during change in thoracic configuration.? [/INST] Stability in lobar ventilation was examined in dogs during bilateral electrophrenic respiration (BEPR) and positive pressure-assisted ventilation (PPAV). Bilateral prior ligation of the lower and middle lobe pulmonary arteries monitoring of upper lobe ventilation as alveolar minute ventilation (VA), middle and lower lobe ventilation as dead space (VD), and VD/VT ratio, both calculated by the Bohr equation. As documented by chest films, transverse and anteroposterior thoracic diameters during BEPR decreased below FRC values whereas thoracic cephalocaudal dimension greatly increased. During PPAV, all thoracic dimensions increased. Despite these dissimilar regional chest movements, VA, VD, and VD/VT ratio were comparable between PPAV and BEPR under conditions of matched tidal volume and respiratory frequency. Stability in upper lobe ventilation during BEPR was maintained by caudal displacement despite the compression of the rib cage, as documented by tantalum bronchography. Lobar-interdependence appears to be the mechanism transmitting negative pleural pressure developed by the diaphragm to the upper lobes via lower and middle lobe inflation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Determination of plasma volume by 113min-labeled transferrin.? [/INST] The binding property of ionic indium (In3+) with plasma transferrin was utilized for determination of plasma volumes (PV) of whole body and individual organs in small animals. Plasma transferrin from a donor rat was labeled with 15-17 muCi 113mIn/ml plasma and injected into the tested rats. PV were determined either by extrapolation to the dilution at time zero (for whole animals) or by calculation of the ratio, organ radiation: radiation of a plasma unit volume (for organs). The reliability of the method for determination of whole-body PV was ascertained by comparing the results obtained with those obtained simultaneously by the Evans blue dilution method. Whole body PV values obtained by the two methods were similar, with a correlation coefficient (r) of 0.997. The short half life of 113mIn enables it to be used with other nuclides which have similar or different energies in the same sample; indium radiation was counted first and after it had disappeared the activity of the other nuclide could be measured. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Maltose transport in Escherichia coli K-12: involvement of the bacteriophage lambda receptor.? [/INST] Mutants affected in lamB, the structural gene for phage lambda receptor, are unable to utilize maltose when it is present at low concentrations (less than or equal 10 muM). During growth in a chemostat at limiting maltose concentrations, the lamB mutants tested were selected against in the presence of the wild-type strain. Transport studies demonstrate that most lamB mutants have deficient maltose transport capacities at low maltose concentrations. When antibodies against purified phage lambda receptor are added to a wild-type strain, transport of maltose at low concentrations is significantly reduced. These results strongly suggest that the phage lambda receptor molecule is involved in maltose transport. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Role of the receptor for bacteriophage lambda in the functioning of the maltose chemoreceptor of Escherichia coli.? [/INST] Chemotaxis towards maltose is specifically defective in many strains of Escherichia coli carrying mutations affecting lamB, the gene coding for the outer membrane receptor for bacteriophage lambda. However, with one exception, the most extreme effect of lamB mutants on the maltose response as determined in the capillary assay is a shift to higher sugar concentrations and a reduction in the number of bacteria accumulated to about 25% of the wild-type level. The severity of the taxis defect is strongly correlated with reduced ability of the cells to take up the maltose present at 1 and 10 muM. Evidence presented here and in the accompanying paper indicates that the lambda receptor is involved in the transport of maltose at these concentrations. The effects of lamB mutations on maltose taxis can be explained by postulating that the high-affinity maltose transport system in which the lambda receptor participates transfers maltose from the surrounding medium across the outer membrane and into the periplasmic space. If the maltose chemoreceptor detects sugar present in the periplasmic space, and not molecules external to the outer membrane, then defective transport of low concentrations of maltose into the periplasm would result in the observed apparent reduction in the sensitivity of the maltose receptor. Thus, the lambda receptor protein would participate in maltose chemorecepton only indirectly through its role in maltose transport. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Isolation of an Escherichia coli mutant deficient in glutathione synthesis.? [/INST] A mutant of Escherichia coli that contains essentially no detectable glutathione has been isolated. The mutant contains a very low level of the enzyme glutathione synthetase and accumulates lambda-glutamyl cysteine at a concentration approximately equal to the level of glutathione found in its parent. No significant differences in growth were observed between the mutant and its parent. However, the activity of at least one enzyme was found to be affected by the absence of glutathione; the specific activity of the B1 subunit of ribonucleoside diphosphate reductase was greatly reduced. The possibility that the decreased B1 activity is due to a mutation in the structural gene coding for B1 or its regulatory gene could be eliminated. This suggests that one role of glutathione in the cell is to maintain at least this one protein in an active state. We propose the designation gshB for the gene coding for glutathione synthetase. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Escherichia coli deoxyribonucleic acid synthesis mutants: their effect upon bacteriophage P2 and satellite bacteriophage P4 deoxyribonucleic acid synthesis.? [/INST] Escherichia coli C strains containing different deoxyribonucleic acid (DNA) synthesis mutations have been tested for their support of the DNA synthesis of bacteriophage P2 and its satellite phage P4. Bacteriophage P2 requires functional dnaB, dnaE, and dnaG E. coli gene products for DNA synthesis, whereas it does not require the products of the dnaA, dnaC, or dnaH genes. In contrast, the satellite virus P4 requires functional dnaE and dnaH gene products for DNA synthesis and does not need the products of the dnaA, dnaB, dnaC, and dnaG genes. Thus the P2 and P4 genomes are replicated differently, even though they are packaged in heads made of the same protein. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Indirect selection of bacterial plasmids lacking identifiable phenotypic properties.? [/INST] A procedure is described that uses an indicator plasmid (pSC201) to identify cells in a bacterial population that have been co-transformed with a second plasmid lacking detectable phenotypic properties. Under appropriate conditions of indirect selection, between 50 and 85% of transformants carrying the indicator plasmid also contain the nonselected plasmid. A temperature-sensitive mutation in the replication functions of the indicator plasmid enables its elimination from doubly transformed bacteria. Using this procedure, we have isolated bacteria that carry only the small cryptic plasmid. P15A, of the Escherichia coli strain 15. This genetic element, which contains only 2,300 nucleotide pairs, is thus capable of functioning as a replicon independently of the two larger plasmids normally associated with it in E. coli 15 strains (Ikeda, Inuzuka, and Tomizawa, 1970). </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Growth rate of Enterobacteriaceae at elevated temperatures: limitation by methionine.? [/INST] The effect of elevated temperatures on growth rate was studied in five strains of Enterobacteriaceae. In all the strains tested a shift to the elevated temperature resulted in an immediate decrease in growth rate which was due to limitation in the availability of endogenous methionine. The first biosynthetic enzyme of the methionine pathway-homoserine transsuccinylase-was studied in extracts of Aerobacter aerogenes, Salmonella typhimurium, and Escherichia coli and was shown to be temperature sensitive in all of them. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Role of methionine in the regulation of serine hydroxymethyltransferase in Eschericia coli.? [/INST] Significant derepression of serine hydroxymethyltransferase is observed when metE or metF mutants of Escherichia coli K-12 are grown on D-methionine sulfoxide instead of L-methionine. The derepression is not prevented by addition of glycine, adenosine, guanosine, guanosine, and thymidine to the growth medium of methionine-limited metF cells showing that the effect is not due to a secondary deficiency of these nutrients. On the other hand, methionine-limited growth of a metA mutant leads to derepression of met regulon enzymes, but only a marginal increase in serine hydroxymethyltransferase activity. A prototrophic metJ strain grown on minimal medium has about the same serine hydroxymethyltransferase as the wild type. The enzyme activity of the metJ strain is not influenced by methionine, but it is partially repressed by glycine, adenosine, and thymidine. metK strains have about twice as much serine hydroxymethyltransferase activity as wild-type cells when grown on minimal medium; but when both types of cells are grown on medium supplemented with glycine, adenosine, guanosine, and thymidine, their enzyme activities are about the same. The results show that methionine limitation can lead to depression of serine hydroxymethyltransferase, but that the regulatory system is different from the one which controls the methionine regulon. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Mutations affecting transport of the hexitols D-mannitol, D-glucitol, and galactitol in Escherichia coli K-12: isolation and mapping.? [/INST] Mutants of Escherichia coli K-12 unable to grow on any of the three naturally occurring hexitols D-manitol, D-glucitol, and galactitol and, among these specifically, mutants with altered transport and phosphorylating activity have been isolated. Different isolation procedures have been utilized, including suicide by D-[3H]mannitol, chemotaxis, and resistance to the toxic hexitol analogue 2-deoxy-arabino-hexitol. Mutations thus obtained have been mapped in four distinct operons. (i) Mutations affecting an enzyme II-complexmt1 activity of the phosphoenolpyruvate-dependent phosphotransferase system all map in gene mtlA. This gene has previously been shown (Solomon and Lin, 1972) to be part of an operon, mtl, located at 71 min on the E. coli linkage map containing, in addition to mtlA, the cis-dominant regulatory gene mtlC and mtlD, the structural gene for the enzyme D-mannitol-1-phosphate dehydrogenase. The gene order in this operon, induced by D-mannitol, is mtlC A D. (ii) Mutations in gene gutA affecting a second enzyme II-complexgut of the phosphotransferase system map at 51 min, clustered in operon gutC A D together with the cis-dominant regulatory gene gutC and the structural gene gutD for the enzyme D-glucitol-6-phosphate dehydrogenase. The gut operon, previously called sbl or srl, is induced by D-glucitol. (iii) Mutations affecting the transport and catabolism of galactitol are clustered in a third operon, gatC A D, located at 40.5 min. This operon again contains a cis-dominant regulatory gene, gatC, the structural gene gatD for galactitol-1-phosphate dehydrogenase, and gene gatA coding for a thrid hexitol-specific enzyme II-complexgat. Other genes coding for two additional enzymes involved in galactitol catabolism apparently are not linked to gatC A D. (iv) A fourth class of mutants pleiotropically negative for hexitol growth and transport maps in the pts operon. Triple-negative mutants (mtlA gutA gatA) do not have further transport or phosphorylating activity for any of the three hexitols. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about "Killer" character does not influence the transmission of mitochondrial genes in Saccharomyces cerevisiae.? [/INST] Three cytoplasmic genetic elements have been shown to be separate from mitochondrial deoxyribonucleic acid (DNA), [rho], in Saccharomyces cerevisiae: the killer character [k], omicron-DNA, and psi [psi]. Griffiths has suggested genetic interactions between [VENR] and [TETR] mutants possibly located on omicron-DNA and mitochondrial genetic markers, but possible interactions between the best characterized of the three, the killer character, and mitochondrial DNA have not been investigated. To test this we isolated cycloheximide-induced nonkiller segregants (NKS) of killer cells with suitable genetic markers and mated them in [k] x [k], [k] x [k], and (NKS) x (NKS) combinations. No differences in quantitative mitochondrial marker transmission between these groups were found in crosses illustrating the mitochondrial phenomena of bias, polarity, and suppressiveness. Our studies show that no intercellular interactions between [k] and (NKS) cells influence mitochondrial transmission genetics. Intracellular interactions between the smaller double-stranded ribonucleic acid of [k] and mitochondrial DNA also were not detected. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Genetic mapping of a mutation that causes ribonucleases III deficiency in Escherichia coli.? [/INST] the mutation that causes ribonuclease III (RNase III) deficiency in strain AB301-105 of Kindler et al. (1973) has been mapped by use of F' merodiploids, Hfr matings, and P1 transduction. This mutation, rnc-105, lies close to nadB, near 49 min on the genetic map of Escherichia coli. The rnc-105 mutation has been transferred from its original genetic background by transduction and conjugation, and these new strains have the same defects in ribonucleic acid processing reported previously for AB301-105. Strains that carry rnc-105 grow more slowly than parental rnc+ strains, but the difference in growth rate seems to depend on the genetic background of each strain. Bacteriophage T7 grows about equally well in RNase III+ and III- female strains of E. coli, even though the specific cuts that RNase III makes in T7 ribonucleic acid are not made in the RNase III- strains. A low-phosphate defined medium in which most E. coli strains seem to grow well was developed. This medium is equally useful for labeling ribonucleic acids with 32PO4 and as a selective medium for genetic manipulations. It was used to determine the growth requirements of strain AB301-105, which are biotin and succinate in addition to the methionine and histidine requirements of the parental strain. The biotin mutation lies near the position expected from known mutations of E. coli, but the succinate mutation apparently does not. The possibility that the succinate requirement could be due to the RNase III deficiency is discussed. A uraP mutation was isolated for use in transferring rnc-105 between strains by conjugation. It lies near 47 min, somewhat removed from the commonly accepted position for uraP. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Mapping and characterization of a mutation in Escherichia coli that reduces the level of ribonuclease III specific for double-stranded ribonucleic acid.? [/INST] Localization of a mutation affecting ribonuclease III activity (an enzyme specific for double-stranded ribonucleic acid) in Escherichia coli was attempted. By a series of matings and transduction experiments, the mutation rnc-105 was mapped near the nadB gene. In strains carrying this mutation, another mutation (ranA2074) was also found. Based on available data, their order on the E. coli chromosome appears to be tyrA, ranA, nadB, rnc, purI. Strains carrying either the ranA2074 or the rnc-105 mutation fail to grow at 45 C in enriched medium, whereas strains carrying only the rnc-105 mutation are defective in ribonuclease III activity. Strains carrying either of these mutations grow more slowly than corresponding wild-type strains in all media tested at all temperatures; the rnc-105 mutation reduces the growth rate more than the ranA2074 mutation. T4 and T7 bacteriophages form plaques with a lower efficiency on strains carrying the rnc-105 mutation than on other strains. Thus we suggest that ribonuclease III is beneficial for normal growth of E. Coli and that at higher temperatures it becomes indispensable. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Transfer ribonucleic acid methylase deficiency found in UGA supressor strains.? [/INST] Extracts of recessive UGA suppressor strains, designated supK, are deficient in transfer ribonucleic acid (tRNA)-methylating activity when compared to wild-type extracts. Moreover, the tRNA from suppressor strains is methyl deficient when compared to wild-type tRNA. This deficiency is due to the lack of a single tRNA methylase activity in suppressor strains. UGA suppressor activity may be caused by the miscoding of one or more methyl-deficient tRNA's in supK strains. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Nature and properties of hexitol transport systems in Escherichia coli.? [/INST] In Escherichia coli K-12 the naturally occurring hexitols D-mannitol, D-glucitol, and galactitol are taken up and phosphorylated via three distinct transport systems by a mechanism called either group translocation or vectorial phosphorylation. For every system, a membrane-bound enzyme II-complex of the phosphoenolpyruvate-dependent phosphotransferase system has been found, each requiring phosphoenolpyruvate, enzyme I, and HPr or alternatively P-HPr as the phosphate donor. Cells with a constitutive synthesis of all hexitol transport systems but with low P-HPr levels have very low transport and phosphorylating activities in vivo, although 40 to 90% of the enzyme II-complex activities are detected in cell extracts of such mutants. No indications for additional hexitol transport systems, especially for systems able to transport and accumulate free hexitols as in Klebsiella aerogenes, have been found. Substrate Km, and Vmax of the three transport systems for several hexitols and hexitol analogues have been determined by growth rates, transport activities, and in vitro phosphorylating activities. Each system was found to take up several hexitols, but only one hexitol serves as the inducer. This inducer invariably is the substrate with the highest affinity. Since bacterial transport systems, as a general rule, seem to have a relatively broad substrate specificity, in contrast to a more restricted inducer specificity, we propose to name the system inducible by D-mannitol and coded by the gene mtlA the D-mannitol transport system, the system inducible by D-glucitol and coded by gutA the D-glucitol transport system, and the system inducible by galactitol and coded by gatA the galactitol transport system. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effects on specific antibodies on the catalytic activity of L-asparaginase from Serratia marcescens and Escherichia coli.? [/INST] Rabbit antisera against highly purified L-asparaginase from Serratia marcescens and from Escherichia coli showed up to 60% inhibition of the catalytic amidohydrolysis of L-asparagine when combined with the homologous enzyme. This inhibition was diminished somewhat against the heterologous enzyme. Kinetic studies in the presence of these antisera showed an increased Kmapp for both homologous and heterologous enzymes using L-asparagine as substrate. In contrast, kinetic studies employing the poor substrate, L-glutamine, showed activation attributable to specific antibodies. This was seen in lower Kmapp values and up to twofold increases in the Vmax over the normal rabbit serum controls. The high degree of cross-inhibition (approximately 80%) and the low degree of cross-reactivity in the quantitative precipitin test (approximately 34%) suggest that these two enzymes possess structural similarities located mainly in the regions of the catalytic sites. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Lag in adaptation to lactose as a probe to the timing of permease incorporation into the cell membrane.? [/INST] If bacteria are incapable of forming and incorporating proteins into the cytoplasmic membranes in all phases of the cell cycle, then not all cells from an asynchronous culture should be capable of growth when switched to a new carbon and energy source whose metabolism requires new membrane function. The transfer of an inducible culture to low lactose provides such a situation since the cells cannot grow unless galactoside permease can function to concentrate the lactose internally. From such experiments, it was concluded that the Y gene product of the lac operon is synthesized, incorporated, and can start functioning in active transport, at any time throughout the bulk of the cell cycle. Not only were the lags before growth re-ensued much shorter than would be expected if the membrane transport capability could only be developed in a small portion of the cycle, but brief pulses of a gratuitous inducer shortened the lags much further. Three types of Escherichia coli ML 30 culture were studied: cells that had exhausted the limiting glucose; cells taken directly from glucose-limited chemostats; and a washed suspension of highly catabolite repressed cells from cultures grown in high levels of glucose and gluconate. The growth studies reported here were performed on-line with a minicomputer. They represent at least an order of magnitude increase in accuracy in estimating growth parameters over previous instrumentation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Isolation of plasmid deoxyribonucleic acid from two strains of Bacteroides.? [/INST] Two clinical isolates of Bacteroides contained covalently closed circular deoxyribonucleic acid (DNA) as shown by sedimentation in an alkaline sucrose gradient, CsCl ethidium bromide equilibrium centrifugation, and electron microscopy. Bacteriodes fragilis N1175 contained a homogeneous species of plasmid DNA with a molecular weight of 25 x 10(6). Bacteroides ochraceus 2228 contained two distinct, covalently closed circular DNA elements. The larger cosedimented with the covalently closed circular DNA form of the R plasmid, R100, corresponding to a molecular weight of 70 x 10(6); the smaller sedimented as a 58S molecule with a calculated molecular weight of 25 x 10(6). The roles of these plasmids are unknown. Neither strain transferred antibiotic resistance to plasmid-negative Bacteroides or Escherichia coli, and neither produced bacteriocins active against other Bacteroides or sensitive indicator strains of E. coli. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Behavior of spindles and spindle plaques in the cell cycle and conjugation of Saccharomyces cerevisiae.? [/INST] The interdependence of spindle plaque with other aspects of cell division and conjugation in Saccharomyces cerevisiae has been investigated. Three forms of the spindle plaque appear sequentially before the formation of the complete, intranuclear spindle. The single plaque is present initially in the mitotic cycle; it becomes transformed into a satellite-bearing single plaque during the latter part of G1. Subsequently, plaque duplication yields the double plaque characteristic of the early phase of budding, which coincides with the period of chromosome replication (S). The eventual separation of these plaques to form a complete spindle, with a single plaque at each pole, is nearly coincident with the completion of S. The form of the plaque differs in two independent cases of G1 arrest: the single plaque is found in a cell in stationary arrest of growth, whereas a cell arrested by mating factors in preparation for conjugation contains a satellite-bearing single plaque. The latter form is retained during zygote formation, where it serves as the initial site of fusion of each prezygotic nuceus with the other. This fusion results in the formation of a single zygotic nucleus with a satellite-bearing single plaque, which is subsequently transformed into a double plaque as the zygote buds. The double plaque is situated adjacent to the site of bud emergence in both vegetative cells and zygotes. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Sizing of bdellovibrio during growth.? [/INST] A technique for the counting and relative sizing of host-independent bdellovibrio during growth, with the aid of a modified Coulter counter, is described. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Recipient ability of bacteriophage-resistant mutants of Escherichia coli K-12.? [/INST] The ability of a wide range of bacteriophage-resistant mutants to act as recipients in conjugation with F'lac pro and R100-1 donors has been studied. A number of mutant types defective in recipient ability with F'lac pro, as well as mutants which were hyperrecptive with R100-1, have been detected. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Bacteriophage Mu-1-induced permeability mutants in Escherichia coli K-12.? [/INST] Apparent permeability mutations were produced in Escherichia coli K-12 by bacteriophage mu-1 mutagenesis. They are pleiotropic mutations showing sensitivity to a number of detergents and unrelated antibiotics, and presumably they affect cell wall or membrane biosynthesis. One of the mutations was genetically mapped at a site in or near the acrA and mtc loci at approximately 10.5 min on the Taylor and Trotter map (1972). </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Characterization of V-prime factors in Escherichia coli K-12.? [/INST] An episome derived from an Hfr(v) (Hfr isolated from a V colicinogenic parent) strain of Escherichia coli K-12 was isolated and characterized. The direction of gene transfer was inverted from that in the original parental strain. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Transductional mapping of gene trmA responsible for the production of 5-methyluridine in transfer ribonucleic acid of Escherichia coli.? [/INST] The gene trmA, responsible for the production of 5-methyluridine (ribothymidine) in transfer ribonucleic acid, has been located at 79 min on the chromosomal map of Escherichia coli K-12. In five-factor crosses the gene order was shown to be argH-trmA-rif-thiA-metA. The co-transduction frequency between argH and trmA was 65%. Furthermore, the trmA5 mutation was shown to be recessive, in agreement with the notion that the trmA gene is the structural gene for the transfer tibonucleic acid (5-methyluridine) methyltransferase. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Physiological and biochemical studies on the function of 5-methyluridine in the transfer ribonucleic acid of Escherichia coli.? [/INST] Matched pairs of transductant strains differing by the presence of absence of 5-methyluridine (ribothymidine) (m5U) in their transfer ribonucleic acid (tRNA) were used to study the function of this modified nucleoside in Escherichia coli. Ordinary measurements of growth rate in different media revealed no effect of the loss of m5U in tRNA. A gene located close to trmA (the structural cistron for the methyltransferase that produces m5U in tRNA), however, was found to reduce the growth rates significantly, depending on the medium and the temperature of cultivation. Measurement of codon recognition, macromolecular composition, tRNA binding to the ribosome, and the rate of protein chain elongation in vivo indicated no disadvantage caused by the lack of m5U. The regulation of ilv and his operons seemed also to be unaffected by the absence of m5U in the tRNA. In a mixed population experiment, however, cells possessing m5U in their tRNA seemed to have a distinct advantage over cells lacking this modified nucleoside. This experiment provides the first indication of the overall value of m5U in tRNA. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A comparison of iliac marrow and biodegradable ceramic in periodontal defects.? [/INST] Defects were created in the tooth-supporting bone of six beagle dogs. Biodegradable tricalcium phosphate was compared to cancellous marrow as a treatment method. The findings indicated that ankylosis and resorption of the tooth can occur when using marrow. The ceramic-filled defects healed slower; but the material itself was well tolerated by the tissues, initiated new bone formation, filled in the defect, and has good potential for the treatment of advanced periodontitis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Thermodynamic considerations of the setting reaction in Ag3Sn amalgams.? [/INST] The setting reaction of Ag3Sn amalgams may be thought of as a liquid phase sintering problem in which the reactants seek to form products with the lowest thermodynamic potential. We discuss the thermodynamic and kinetic considerations of this reaction. The lowering of free energy has been given as the reason for the formation of the gamma1, gamma2,and beta1 phases and a qualitative reaction coordinate diagram has been hypothesized. The barrier height for the formation of the beta1 phase has been determined to be 137 kJ/mol. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Use of PMMA in expansion dental implants.? [/INST] The Polymer Expansion Implant System, which is a system for the substitution of missing dental roots in natural or surgical alveolus, has been developed by the author. The polymer used is poly (methyl methacrylate) (PMMA). A material is sought that has three of the basic physical and mechanical qualities of human dentine: low modulus of elasticity, thermal and electrical passiveness, and ideal porosity. In addition it should be resistant, easily worked, biocompatible, and of low cost. Of the biomedical polymers, PMMA has these qualities, and it can be used as a substitute for dental roots. The design of bodies to be implanted as substitutes for dental roots requires: anatomical measurements of the maxilla and sockets; methods of retention by the bone tissue; and methods of insertion. The formation of lamina dura around an implanted body is a reply of the organism to the forces acting on it and a demonstration of the good interaction of the porosity of the material, the peri-implant collagenous fibers and bone. X-rays that demonstrate the behavior of bone to a PMMA implant are shown. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A failed vitallium/stainless steel total hip replacement: a case report with histological and metallurgical examination.? [/INST] A case of a failed total hip replacement consisting of a Vitallium hip socket and a stainless steel femoral head prosthesis is presented. The mixed-metal combination and inadequate design resulted in severe abrasive wear and fretting corrosion of the bearing surface, and the accumulation of stainless steel wear debris and corrosion products in the periarticular tissues was extensive. The tissue response was primarily fibrotic scarring with severe histiocytic and mild foreign body giant cell reaction. Despite the massive accumulation of wear debris and corrosion products, however, there was minimal chronic inflammation and no acute inflammation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of prolonged LH-releasing hormone administration on gonadotropin response in patients with hypothalamic and pituitary tumors.? [/INST] The effect of prolonged administration of synthetic LH-RH (400 mug daily im for 5 days) on gonadotropin response to LH-RH (100 mug single injection iv) was compared in 13 patients with pituitary tumors or suprasellar tumors. No patients with pituitary tumors exhibited an augmented response on serum FSH and LH after prolonged LH-RH administration. A paradoxical fall in response to LH-RH test occurred in 3 patients with pituitary tumors and in a patient with hypothalamic tumor in whom gonadotropin responses were normal on the first LH-RH test. On the other hand, 2 patients with suprasellar tumors with a low response to the initial LH-RH test showed significant increase on a second LH-RHtest after consecutive LH-RH administration. Consecutive administration of LH-RH may help to distinguish between the hypogonadism of pituitary origin and that of hypothalamic origin when the initial LH response to a single dose of LH-RH is subnormal. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Pituitary response to synthetic luteinizing hormone-releasing hormone in patients with Turner's syndrone.? [/INST] Synthetic luteinizing hormone-releasing hormone (LHRH) was administered intravenously in a dose of 25 mug to 9 patients with Turner's syndrome of 45,XO karyotypes, 5 normal menstruating women, and 5 postmenopausal women. In patients with Turner's syndrome, the basal serum LH level was higher than that of the normal subjects and lower than that of postmenopausal women. The LH response to LHRH, when expressed as a percent of control, was comparable to that of the normal luteal phase and significantly higher than that of postmenopausal women. The basal FSH level was more elevated than the basal LH level. The FSH response to LHRH, when expressed as a percent of control, was similar to that of postmenopausal women and lower than that of normal subjects. The results suggest that pituitary function is preserved in patients with Turner's syndrome. I interpret the pituitary responsiveness and/or reserve of patients with Turner's syndrome as larger than that of postmenopausal women. A greater response of LH than of FSH to LHRH was observed in this study and is contrary to findings reported by others on teenage patients with Turner's syndrome. This suggests that the sensitivity of gonadotropins changes with age in Turner's syndrome. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Detection of bacteriuria by luciferase assay of adenosine triphosphate.? [/INST] A selective method for distinguishing bacterial and nonbacterial adenosine triphosphate (ATP) in clinical bacteriological specimens was studied. The method involved incubation of samples with the detergent Triton X-100 and the ATP-hydrolyzing enzyme apyrase. The incubation selectively destroyed ATP in suspensions of various human cells while not affecting the ATP content in microbial cells. ATP remaining in the sample after incubation was extracted in boiling buffer and assayed by the firefly luciferase assay. Application of the method to 469 clinical urine specimens showed that the ATP level after treatment with Triton/apyrase was correlated to bacterial counts and that the sensitivity of the assay was sufficient for the detection of 10(5) bacteria/ml. The ATP levels per bacterial cell remaining in the urine specimen after treatment with Triton/apyrase were close to values observed in laboratory-grown cultures. The specificity and sensitivity of the luciferase assay for the detection of urinary bacteria and its possible use as a bacteriuria screening method are discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Unusual Enterobacteriaceae: a Salmonella cubana that is urease positive.? [/INST] This is the first report of a naturally occurring Salmonella that is urea positive. The strain was identified as Salmonella cubana and it was typical in all biochemical, serological, and bacteriophage reactions, except that is produced urease strongly. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Evaluation of the Bactrol Disks, a set of quality control cultures.? [/INST] A set of commercially available quality control cultures was evaluated. These cultures were found to be an acceptable alternate to lyophilized or continuously subcultured cultures for a quality control program. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Rapid hippurate hydrolysis method for presumptive identification of group B streptococci.? [/INST] A rapid test to detect the hydrolysis of sodium hippurate by beta-hemolytic streptococci within 2 h was developed. All group B streptococci tested were positive using this method and all other groups were negative. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Comparison of four methods for determining nitrate utilization by cryptococci.? [/INST] This study evaluated the following methods for determining nitrate utilization: Wickerham broth, a special nitrate broth, Delft plate, and nitrate strip. With 236 isolates of cryptococci as test organisms, the special nitrate broth method gave 99% correct results and the Wickerham broth method gave 98%. The nitrate strip and Delft plate methods gave correct results in 94 and 86% of tests, respectively. The special nitrate broth method is judged superior because it provides accurate results within 48 h, compared to 14 days with the Wickerham broth method. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of acetone fixation on infectivity and antigenicity of respiratory syncytial virus and adenovirus in the fluorescent antibody test.? [/INST] An investigation was made on the effect of acetone fixation on infectivity and immunofluorescent antigenicity of respiratory syncytial virus and adenovirus type 5, lipid- and nonlipid-containing viruses, respectively. Viruses were allowed to replicate in HEp-2 cells, and the cells were then fixed in acetone at 5 C for periods ranging from 30 s to 7 days. Treatment for 10 min was sufficient to inactivate respiratory syncytial virus, whereas infectious adenovirus type 5 could be isolated from cells immersed in acetone for 7 days. There was a gradual reduction, to 50% of that observed at 30 s, in the intensity of fluorescent antibody staining of both viruses with increasing fixation time, but no significant decreases in fluorescent antibody end-point titers of antisera to either virus were observed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Standardization and evaluation of the CAMP reaction for the prompt, presumptive identification of Streptococcus agalactiae (Lancefield group B) in clinical material.? [/INST] Primary cultures of clinical material were screened for the presence of colonies suspected of being Streptococcus agalactiae (Lancefield group B). Sixty-three such cultures and 108 other isolates of beta-hemolytic streptococci (groups A, C, and G), encountered during the first 3 months of the investigation, were studied by Lancefield grouping, sodium hippurate hydrolysis, and a standardized CAMP test. All streptococci were inoculated perpendicularly to streaks of a beta-toxin-producing staphylococcus on sheep blood agar plates and incubated aerobically in a candle jar and anaerobically at 37 C. Plates were examined after 5 to 6 and 18 h of incubation. The production of a distinct "arrowhead" of hemolysis was indicative of a positive CAMP reaction. All group B streptococci produced a positive CAMP reaction in the candle jar or anaerobically, usually within 5 to 6 h, and aerobically after 18 h of incubation. All group A streptococci produced a positive reaction only under anaerobic conditions. Groups C and G streptococci were negative under all atmospheres. The CAMP reaction is a prompt and reliable procedure for the presumptive identification of group B streptococci when a candle jar atmosphere is used during incubation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Rapid identification of group B streptococci by counterimmunoelectrophoresis.? [/INST] Beta-hemolytic streptococcal isolates have been examined by counterimmunoelectrophoresis (CIE) with group B antiserum to determine whether this techinque is of value in the rapid identification of group B strains. Ninety stock cultures and 100 clinical isolates of beta-hemolytic streptococci including representatives of groups A, D, C, G, and B were inoculated into Todd-Hewitt broth; after incubation at 37 C for 1, 2, 3, and 4 h, aliquots of the whole broth cultures were removed and tested by CIE. Antigen was not regularly detected in the 1-, 2-, and 3-h samples, but after 4 h all 126 group B streptococcal strains identified by the capillary precipitin reaction gave CIE precipitin bands with group B antiserum. None of the 58 non-group B strains gave precipitin reactions with this antiserum. Cerebrospinal fluid from an infant with group B streptococcal meningitis and peritoneal fluid from a patient with group B streptococcal peritonitis had free group B antigen detected by the CIE technique. CIE of broth cultures and direct body fluids appears to be a rapid and sensitive method for the identification of group B streptococcal strains. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Pagano-Levin Candida test medium: evaluation using vaginal samples.? [/INST] Since 1958 pagano-Levin medium (PLM) has been used as an aid in the identification of Candida albicans. However, no statistical analysis of its effectiveness based on large number of random human specimens has been reported. The present study compared PLM (now called Candida test) with Sabouraud's plus antimicrobials and Littman's ox-gall agar without antimicrobials. Of 500 random vaginal samples 24.8 were true positives, 71.9% were true negatives, 2.2% were false positives, and 1.2% were false negatives on PLM. If only samples identified as C. albicans were considered, 95.4% were true positives and 4.6% were false negatives. PLM did not inhibit C. albicans from the vagina. No one medium was found superior to the others for the purpose of isolating and identifying C. albicans. Of the five strains of C. parapsilosis, the only other Candida species isolated, all the samples grew on PLM but most were inhibited on Sabouraud's medium plus antimicrobials. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Serotyping and biotyping of 160 Escherichia coli strains: comparative study.? [/INST] One hundred and sixty Escherichia coli strains were serotyped and biotyped. Serotyping revealed 68 different types, with 25 strains not typable. Biotyping was possible in all strains but revealed 55 different types. One biotype could be subdivided into 35 different serotypes, indicating that for this biotype the series of biochemical and fermentation reactions could be extended for further differentiation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Sensitivity of bhk-21 cells supplemented with diethylaminoethyl-dextran for detection of street rabies virus in saliva samples.? [/INST] A tissue culture system for detecting rabies virus from saliva samples of suspected animals was developed and compared to suckling mouse inoculation. Swab samples were obtained from the mouth of the animal heads received for rabies diagnosis; these swabs were submerged in maintenance medium. The maintenance medium was inoculated intracerebrally into suckling mice and onto BHK-21 cells with diethylaminoethyl (DEAE)-dextran (BHK/DEAE) and without (BHK). Rabies immunofluorescence was performed on the brain of the mice dying during the observation period and also on both tissue culture systems every day after infection. The BHK-DEAE system detected 28 positive samples obtained from 48 rabid animals and the BHK system detected 18. By suckling mouse inoculation only 11 of the same positive samples were detected. A total of 90 samples was studied by the three methods. Rabies virus was detected by the tissue culture methods earlier than by suckling mouse inoculation. The BHK-DEAE method was an economic and fast method for rabies virus detection in saliva samples, which could be used for ecological and pathogenesis studies, as well for rabies diagnosis before the death of the suspected animal. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Suitability of peracetic acid for sterilization of media for mycoplasma cultures.? [/INST] The utility of peracetic acid for sterilization of serum and yeast extract additions to mycoplasma medium was studied by culturing six Mycoplasma species. Culture media containing additions that had been sterilized with peracetic acid proved to be as good as filtered components. The use of 0.05 to 0.1% peracetic acid is recommended to sterilize the serum and yeast extract additions since savings in time and equipment can be accomplished. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Simplified microimmunofluorescence test with trachoma-lymphogranuloma venereum (Chlamydia trachomatis) antigens for use as a screening test for antibody.? [/INST] A simplified microimmunofluorescence test with trachoma-lymphogranuloma venereum (Chlamydia trachomatis) antigens has been devised as a screening test for antibody in human sera. The test differs from our standard procedure by amalgamating 15 different immunotypes into nine antigen pools, by using only three serum dilutions, and by dropping use of duplicate slides. The screening test could be performed on at least six times as many sera as the standard test for a given unit of effort. It was shown to have a sensitivity equal to the standard test and an ability to determine specific immunotype on the basis of antibody pattern (72%) only slightly reduced from the standard test (84%). The screening test was carried out on 876 patients from different population groups in the Seattle area. The tests showed that antibody was present frequently in persons attending venereal disease clinics (60%) and commonly (25%) in a group of adults without venereal disease. Nine percent of children under 15 years of age tested had antibody; the significance of this finding is unknown. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Identification of streptococci: serogrouping by immunofluorescence.? [/INST] This paper deals with the fluorescent antibody (FA) method for identifying six commonly occuring and two rare groups of streptococci by using commercially prepared (Difco) conjugates. We have shown that group-specific FA produced frequent cross-reactions with heterologous groups of organisms. These reactions varied with different strains of the same serogroup. Nonetheless, there was distinct overall patterns in the intensity and appearance of the homologous and heterologous reactions. When monitored by the precipitin test with Rantz and Randall extracts, these patterns led to the correct identification of 90 to 100% of specimens of serogroup A, B, C, and G streptococci. Many members of groups D and F also showed distinctive reaction patterns. However, there was a significant number of strains of both groups D and F that either failed to strain or stained poorly with the homologous conjugate. As a result, the identification of these serogroups by FA was less reliable. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Antibody response of patients with malignancies to bacteremia with gram-negative bacteria.? [/INST] Antibody response, determined by means of the indirect bacterial hemagglutination tests, was studied in 58 consecutive patients with various malignancies whose blood culture yielded growth of Enterobacteriaceae or Pseudomonas and from whom serum specimens were obtained. Of these patients 59% had a significant antibody response. The invading microorganisms were Escherichia coli in 33 and Klebsiella in 19 subjects, an antibody response being documented with essentially equal frequency (60 and 57% of the subjects, respectively). Two patients had positive blood cultures for both E. coli and Klebsiella, one of whom had a significant response to one isolate only. A specific antibody resonse was documented in 67% of the subjects from whom blood for antibody titration was obtained at least 5 days after the blood culture, but from only 21% of patients whose serum was procured during the first 5 days after the blood culture. Similarly, such an antibody response was identified in 73% of subjects with two consecutive serum specimens, but in only 28% of the patients with a single serum specimen for antibody titration. Documentation of the immune response may be of diagnostic aid in differentiating between infection and contamination even in patients with underlying malignancy and under potentially immunosuppressive therapy. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Laboratory experience with a radiometric method for detecting bacteremia.? [/INST] Two bacteriologic systems for detecting bacteria in blood were compared; the automated radiometric BACTEC and the conventional method used in our laboratory for many years. BACTEC consisted of two bottles with 30 ml and the conventional method with 50 ml of media for aerobes and anaerobes. The BACTEC bottles were inoculated with 2 to 3 ml and the conventional with 4 to 5 ml of blood at the patient's bedside. Out of the 3,045 blood specimens cultured (804 patients), 262 (117 patients) were positive by one or both methods. The conventional system detected 5more cultures. The explanation of the differences is discussed. Positive blood cultures were detected by the BACTEC procedure as early as 6 h after the blood collection. In the first 24 h, on the average, 77% of aerobic organisms were detected by the BACTEC as compared to 48% by the conventional system. All anaerobic BACTEC cultures were positive within 4 days, whereas the conventional system detected at that time 74%. At day 4, 67% of fungi were detected by the BACTEC and only 27% by the conventional system. Of the 3,045 blood cultures examined by the BACTEC, 208 were recorded as false positive with growth index readings ranging from 30 to 59. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Assessment of virus infectivity by the immunofluorescent and immunoperoxidase techniques.? [/INST] The immunofluorescent and immunoperoxidase cell-counting techniques were comparable in precision and reproducibility for the quantitative assessment of influenza virus infectivity. The dose-response function was linear with each procedure, and comparable results were obtained for estimating neutralizing antibodies in antiviral serum. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A simple test system for the separation of staphylococci from micrococci.? [/INST] A simple test system for the separation of staphylococci from micrococci is described, which is based on the ability of staphylococci to produce acid aerobically from glycerol in the presence of 0.4 mug of erythromycin per ml and on their sensitivity to lysostaphin. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Fluorescent antibody studies in chlamydial infections.? [/INST] Irradiated McCoy cells infected with genital strains of Chlamydia trachomatis were grown in wells on slides coated with polytetrafluoroethylene. The inclusions produced in this system formed the antigen in an indirect immunofluorescence test, which detected group-specific chlamydial antibodies in sera from patients attending veneral disease clinics. Chlamydial antibodies were found more frequently and in higher titer in sera from women attending veneral disease clinics then in sera from a less promiscuous population attending a Family Planning Association clinic. Paired sera from 13 patients with nongonococcal urethritis from whom chylamydiae had been isolated were tested against the homologous isolates; seroconversion was demonstrated in only one instance, and antibody was present in the first serum specimens of all the other patients. Chlamydia-specific immunoglobulin M was found in four of eight patients with psittacosis and in a proportion of sera from patients attending veneral disease and Family Planning Association clinics. The antigen for this immunofluorescence test can easily be prepared in laboratories with cell culture facilities for the isolation of C. trachomatis, and the test should be useful for laboratories which cannot undertake the micro-immunofluorescence test. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A more complete evaluation of the color-coded antigen for the automated reagin test.? [/INST] A comparative study, on 500 samples, of the toluidine red antigen, one of the low-cost, color-coded antigens for the Automated Reagin Test, shows a greater sensitivity than the rapid plasma reagin card antigen. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Recovery of Cryptococcus neoformans from modified Dubos liquid medium utilized for isolation of mycobacteria.? [/INST] Cryptococcus neoformans was isolated from nine pathological specimens cultured for mycobacteria. Five of these were recovered only in liquid TBC medium in the absence of growth on conventional substrates. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Serological diagnosis of California (La Crosse) encephalitis by immunofluorescence.? [/INST] A method of indirect immunofluorescence was developed and examined retrospectively as a serological test for the laboratory diagnosis of California encephalitis (CE). LaCrosse virus immunofluorescence immunoglobulin (Ig) G and IgM studies were done on paired sera from 50 patients with acute central nervous system infections. CE had been documented in 25 patients by hemagglutination inhibition, neutralizing, complement fixing, and/or precipitin tests. Five (20%) of the acute and 16 (64%) of the convalescent sera from CE patients had La Crosse IgM antibodies. Seven (28%) of the acute and all of the convalescent CE specimens had La Crosse IgG antibodies. Titers ranged from less than 4 to 256. IgG antibodies were present in all 11 sera collected 1 to 2 years after CE, but IgM antibodies were absent. The 25 serum pairs from patients who did not have CE were negative for IgM and IgG antibodies. This study indicated that La Crosse immunofluorescence antibody tests were as sensitive and specific for CE as conventional hemagglutination-inhibition tests, and would detect at least 20% of patients during their acute illness. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Rapid identification of swarming Proteus using the PathoTec ornithine decarboxylase test strip.? [/INST] The PathoTec ornithine decarboxylase test strip was evaluated for use in identification of swarming Proteus. All 181 strains tested were accurately identified within 4 h. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Growth potential of cottonseed culture media for various clinically significant aerobic bacteria.? [/INST] Enzymatic hydrolysates of various cottonseed flours were prepared with the proteolytic enzymes bromelain, HT-200, Pronase, and trypsin. The growth of various aerobic bacteria of clinical significance in these hydrolysates was compared to that obtained with a standard casein-soybean peptone culture medium, Trypticase soy. The generation times of the majority of bacteria grown in the bromelain cottonseed flour hydrolysate were shorter than that obtained with the standard control broth. A bromelain cottonseed flour hydrolysate agar preparation supported the growth of the bacteria comparably to that of the casein-soybean agar substrate. All the bacterial colonies were larger on the bromelain cottonseed flour hydrolysate blood agar medium than those grown on the control agar. The peptones derived from the enzymatic hydrolysis of cottonseed flour are sufficient to promote the rapid and luxuriant growth of a wide spectrum of aerobic bacteria without the addition of peptone from other sources. It is suggested that cottonseed flour peptones be utilized as a nutrient source in general-purpose media for the clinical microbiology laboratory. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Pigment production by Cryptococcus neoformans from para- and ortho-Diphenols: effect of the nitrogen source.? [/INST] Cryptococcus neoformans produced pigments when p-diphenols were substrates in a glucose-amino acid-salts medium. The best substrates were 2.5-dihydroxybenzoic acid and 2,5-dihydroxybenzenesulfonic acid. In contrast to the cellular pigment production from o-diphenols (hydroxyl groups in the 2,3- or 3,4-position of phenyl ring), the p-diphenols (1,4- or 2,5-positions for the hydroxyl groups) produced large amounts of soluble pigments that diffused into the medium. When an optimal source of nitrogen (glutamine, glycine, and asparagine) was used, 89% of the C. neoformans strains produced pigments from p-diphenols. In contrast, 0 to 67% of the strains produced pigments when a suboptimal nitrogen source (proline, ammonium sulfate, ornithine, and methionine) was used. When glutamine-glycine-asparagine was the nitrogen source, 100% of the C. neoformans strains produced pigments from o0diphenols, whereas 77 to 100% of the strains produced pigment when proline-ammonium sulfate-ornithine-methionine was the nitrogen source. Cryptococcus species other than C. neoformans and all tested Candida species failed to produce pigments from any of the substrates except when hydroquinone was used. A combination of glutamine-glycine-asparagine and 3,4-dihydroxyphenylalanine allowed differentiation of colonies of C. neoformans from C. albicans in 3 to 6 days. These data showed that pigment production from o- and p-diphenols served as an excellent biochemical test for the identification of C. neoformans. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Construction of an interpretive pattern directory for the API 10 S kit and analysis of its diagnostic accuracy.? [/INST] A directory of test patterns and their interpretations has been prepared for identification of Enterobacteriaceae by using the 11-test API 10 S kit. The diagnostic accuracy of the directory and kit were evaluated by using records of test results for 37,476 isolates studied with the 21-test API 20 Enteric kit. Analysis indicates that 96.9% of the isolates would have been correctly identified at the genus level and 95.9% at the species level by using only the subset of tests included in the API 10 S. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Anaerobic bag culture method.? [/INST] In a new method of anaerobic culture, a transparent, gas-impermeable bag is used and the anaerobic environment is established with copper sulfate-saturated steel wool. An Alka-Seltzer tablet generates carbon dioxide. The agar plate surface can be inspected through the bag at any time without interrupting the anaerobic atmosphere or disturbing other specimens. Methylene blue indicator strips are completely reduced by 4 h after the bag is set up and have remained reduced for as long as 3 weeks. Growth of 16 different stock culture anaerobes was generally equivalent by the bag and GasPak jar methods. Yield and growth of anaerobic isolates also were equivalent with 7 of 10 clinical specimens; from the other 3 specimens, 13 isolates were recovered, 5 by both the bag and jar methods and the rest by one method or the other. No consistent differences were found between the anaerobic bag and GasPak jar methods in the yield of anaerobes from clinical specimens. Early growth (24 h of incubation) of anaerobes from one specimen was detected with the bag method. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Analysis of acetoin and diacetyl in bacterial culture supernatants by gas-liquid chromatography.? [/INST] The acetoin and diacetyl contents of culture supernatants of Voges-Proskauer-positive "viridans" streptotocci, Klebsiella pneumoniae and Staphylococcus aureus, were determined by a gas liquid chromatographic procedure, in which supernatants were extracted with diethyl ether and diacetyl was measured on columns of 10% (wt/wt) polyethylene glycol 400 (PEG 400) at 73 C. Acetoin was converted to diacetyl, before analysis, by a simple oxidation procedure with ferric chloride and without a distillation step. Streptococcal culture supernatants were shown by this method to contain only acetoin; supernatants of K. pneumoniae and S. aureus contained both acetoin and diacetyl. </s>