sentence: These observations point to fungal biofilm as a source of potential receptors for P. gingivalis cell surface components and support the hypothesis that these biofilms form a protective environment for bacterial growth.The preliminary gene expression analysis in our current study revealed that the expression of genes encoding the main fungal adhesins increased significantly under normoxia , whereas the aspartic protease-encoding genes , among which SAP5 and SAP6 have been identified as the major biofilm-related genes , seemed to be mainly involved in fungal cell protection or defense against the bacterial neighborhood under anoxic conditions.The following surface components of P. gingivalis were previously identified to be involved in cell-to-cell interactions : lipopolysaccharides ( LPS ) , fimbriae , internalines and cysteine proteinases , i.e. gingipains .