Isolation of extracellular antibiofilm polypeptides from filamentous fungi

Antibiotic resistance among microorganisms poses a great threat to human health. Since, discovery of new antibiotics is necessarily needed. Antimicrobial polypeptides (AMP), which are synthesized as part of the immune systems of prokaryotic and eukaryotic organisms, are emerging as new generation antibiotics. AMPs are amino acid sequences that are short chain and usually cationic. Antibiofilm peptides (ABP) are a subset of AMPs and are polypeptide sequences that inhibit biofilm formation. In this thesis study, the filamentous fungus was isolated from the soil, and the presence of ABP was detected in culture filtrates of these filamentous fungi. Two AMP-producing fungi were identified against Staphylococcus aureus (ATCC 25923) and methicillin resistant S. aureus (MRSA) by well diffusing, cross streak, radial inhibition and trypsin / proteinase K digestion methods. One of these fungi was ABP producer. Molecular characterization of ABP producer filamentous fungus was made and it was determined that this species is Aspergillus tubingensis. The proteins isolated by trichloroacetic acid (TCA) method and are shown by SDS-PAGE and tricine-PAGE. This ABP molecule was determined by MALDI-TOF/MS. The minimum inhibitory concentration (MIC) value for S. aureus was 32 mg / L, and the minimum biofilm inhibitory concentration (MIC) value was 2 mg / L. This protein is uncharacterized protein (A0A1L9MXD7_ASPTU) from UniProt database. In conclusion, the presence of ABP in filamentous fungi has been demonstrated for the first time and the potential ABP that can be used in biofilm related infections of S. aureus has been suggested.