Contributions of Hemolytic Proteins in Virulent Aeromonas hydrophila to Motile Aeromonas Septicemia Disease of Channel Catfish (Ictalurus punctatus).

IF 2.2 4区生物学 Q3 MICROBIOLOGY

Fems Microbiology Letters Pub Date : 2024-12-10 DOI:10.1093/femsle/fnae108

Dunhua Zhang, Jun Feng, Yi Wang, Craig A Shoemaker, Allison A Wise, Benjamin H Beck

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引用次数: 0

Abstract

Hemolytic proteins are a major group of virulence factors in pathogenic Aeromonas hydrophila. Six genes encoding presumable hemolytic proteins were revealed from the genome of virulent A. hydrophila (vAh) that caused severe disease in channel catfish. The aim of this study was to assess the contribution of these hemolytic proteins to the virulence of this bacterium. Genes coding for following six proteins were investigated: aerolysin (Arl), 21-kDa hemolysin (Hly1), thermostable hemolysin (Hly2), phospholipase/lecithinase-related hemolysin (Hly3), membrane-associated hemolysin III (Hly4), and cytolysin-associated hemolysin (Hly5). Individual genes were deleted from the bacterium using CRISPR-Cas9 mediated methods. Assessment showed that deletion of Arl gene (Δarl) completely abolished hemolytic activity of this mutant while Δhly1-Δhly5 mutants had the same activity as the wild vAh. Extracellular proteins (ECP) of the Δarl mutant caused significantly (p < 0.01) less cell death in vitro with viability increased by approximately 20%, compared to the wild vAh. ECPs of mutants Δhly1-Δhly5 remained the same cell toxicity as the wild vAh. A second deletion of hly5 from the Δarl mutant further lowered the cell toxicity of the ECP of the mutant (Δarl+Δhly5). Assays in vivo showed that both Δarl and Δhly5 mutants caused less fish mortality with reduction of 57% and 16%, respectively, compared to the wild vAh; the Δarl+Δhly5 mutant caused the least mortality with approximately 87% of reduction; and other mutants had the same virulence as the wild vAh. Analyses of SDS-PAGE and Western blotting evidently indicate that both Arl and Hly5 proteins formed hexamer-like stable structures post secretion from the bacterium. Arl and Hly5 apparently had synergistic action in cytotoxicity and causing disease and were the major virulence factors among the six hemolytic proteins analyzed in this study.

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来源期刊

Fems Microbiology Letters 生物-微生物学

CiteScore

4.30

自引率

0.00%

发文量

112

审稿时长

1.9 months

期刊介绍： FEMS Microbiology Letters gives priority to concise papers that merit rapid publication by virtue of their originality, general interest and contribution to new developments in microbiology. All aspects of microbiology, including virology, are covered. 2019 Impact Factor: 1.987, Journal Citation Reports (Source Clarivate, 2020) Ranking: 98/135 (Microbiology) The journal is divided into eight Sections: Physiology and Biochemistry (including genetics, molecular biology and ‘omic’ studies) Food Microbiology (from food production and biotechnology to spoilage and food borne pathogens) Biotechnology and Synthetic Biology Pathogens and Pathogenicity (including medical, veterinary, plant and insect pathogens – particularly those relating to food security – with the exception of viruses) Environmental Microbiology (including ecophysiology, ecogenomics and meta-omic studies) Virology (viruses infecting any organism, including Bacteria and Archaea) Taxonomy and Systematics (for publication of novel taxa, taxonomic reclassifications and reviews of a taxonomic nature) Professional Development (including education, training, CPD, research assessment frameworks, research and publication metrics, best-practice, careers and history of microbiology) If you are unsure which Section is most appropriate for your manuscript, for example in the case of transdisciplinary studies, we recommend that you contact the Editor-In-Chief by email prior to submission. Our scope includes any type of microorganism - all members of the Bacteria and the Archaea and microbial members of the Eukarya (yeasts, filamentous fungi, microbial algae, protozoa, oomycetes, myxomycetes, etc.) as well as all viruses.