sentence: This finding is consistent with the study by Patzelt and colleagues on polyether antibiotics monensin A in Streptomyces cinnamonensis A3823.5 and nigericin in Streptomyces hygroscopicus V1327 and Streptomyces violaceusniger NRRL B-1865 , who demonstrated a clear stimulatory effect of heptakis-2 ,6 - di-O-methyl β - cyclodextrin ( DMCD ) on the production of these compounds in shaken liquid cultures .