AUTHOR=Du Hechao , Pang Maoda , Dong Yuhao , Wu Yafeng , Wang Nannan , Liu Jin , Awan Furqan , Lu Chengping , Liu Yongjie 

TITLE=Identification and Characterization of an Aeromonas hydrophila Oligopeptidase Gene pepF Negatively Related to Biofilm Formation

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.01497

DOI=10.3389/fmicb.2016.01497

ISSN=1664-302X

ABSTRACT=<p>Bacterial biofilms are involved in adaptation to complex environments and are responsible for persistent bacterial infections. Biofilm formation is a highly complex process during which multifarious genes work together regularly. In this study, we screened the EZ-Tn5 transposon mutant library to identify genes involved in biofilm formation of <italic>Aeromonas hydrophila</italic>. A total of 24 biofilm-associated genes were identified, the majority of which encoded proteins related to cell structure, transcription and translation, gene regulation, growth and metabolism. The mutant strain TM90, in which a gene encoding oligopeptidase F (<italic>pepF</italic>) was disturbed, showed significant upregulation of biofilm formation compared to the parental strain. The TM90 colony phenotype was smaller, more transparent, and splendent. The adhesive ability of TM90 to HEp-2 cells was significantly increased compared with the parental strain. Fifty percent lethal dose (LD<sub>50</sub>) determinations in zebrafish demonstrated that the enhanced-biofilm mutant TM90 was highly attenuated relative to the wild-type strain. In conclusion, the <italic>pepF</italic> gene is demonstrated for the first time to be a negative factor for biofilm formation and is involved in <italic>A. hydrophila</italic> pathogenicity.</p>