Outer membrane protein A (OmpA) is a potential virulence factor of Vibrio alginolyticus strains isolated from diseased fish

Abstract

Vibrio alginolyticus is one of the most serious causative agents of diseases in cultured marine fish and shellfish. However, the characteristics of virulence factors in pathogenic V. alginolyticus are poorly known. To gain insight into fish diseases caused by V. alginolyticus, we carried out two-dimensional gel electrophoresis (2-DE) combined with MALDI-TOF mass spectrometry to identify uniquely expressed proteins in the disease-causing V. alginolyticus. V. alginolyticus strains were isolated from marine environments and diseased fish obtained from southern Thailand. We identified seven unique proteins in the disease-causing V. alginolyticus strain. Among those, the outer membrane protein A (OmpA) had the strongest expression. Therefore, the function of this protein was further analysed. To investigate the role of OmpA protein, an in-frame deletion mutant of ompA was constructed using the homologous recombination method. Although the ompA mutant V. alginolyticus strain (ΔompA) grew normally, the mutant exhibited a significant defect in the swarming ability and the biofilm formation. Furthermore, Galleria mellonella larvae injected with the mutant bacteria had a significantly greater survival percentage than those injected with the wild-type strain, demonstrating that OmpA protein is required for the pathogenicity of V. alginolyticus. Together, this study suggests a potential target for vaccine development against pathogenic V. alginolyticus strain. K E Y W O R D SGalleria mellonella, MALDI-TOF mass spectrometry, ompA, two-dimensional gel electrophoresis, Vibrio alginolyticus How to cite this article: Bunpa S, Chaichana N, Teng JLL, et al. Outer membrane protein A (OmpA) is a potential virulence factor of Vibrio alginolyticus strains isolated from diseased fish. J Fish Dis. 2020;43:275-284. https ://doi.

Strategies for Rapid Identification of Acinetobacter baumannii Membrane Proteins and Polymyxin B’s Effects

“…Among the 15 membrane proteins, the reduced expression of SurA (D0C7T2), which is important for the biogenesis of β-barrel outer membrane proteins (OMPs), would damage the homeostasis and functions of the cell envelope ( Behrens-Kneip, 2010 ; Humes et al., 2019 ). The expression level of OmpA family protein (D0C8N6), a major component of OMPs, is suppressed, which interrupts bacterial antibiotic resistance, infection, and immunomodulation ( Bunpa et al., 2020 ). What is more, OmpA was reported to be identified in the colistin-resistant Enterobacter asburiae ( Ayoub Moubareck, 2020 ), indicating the potential important roles of OmpA in the mechanism of actions and resistance development.…”

“…Membrane proteins play vital roles not only in defense and immunity but also in essential physiological functions, such as the generation or conversion of energy, the import or export of metabolites, the extrusion of toxic substances or antibiotics, and the homeostasis of metal ions ( Ansgar and Dirk, 2010 ). Many membrane proteins were found to be related to drug resistance or potential therapeutic targets, such as OmpA in A. baumannii ( Bunpa et al., 2020 ).…”

“…Many membrane proteins were found to be related to drug resistance or potential therapeutic targets, such as OmpA in A. baumannii (Bunpa et al, 2020).…”

Virulence of Vibrio alginolyticus Accentuates Apoptosis and Immune Rigor in the Oyster Crassostrea hongkongensis

“…Human infections by V. alginolyticus occur primarily through consumption of insufficiently cooked aquatic food products, with consequences such as diarrhea, gastroenteritis, and septicemia (2). More importantly, V. alginolyticus has been recognized as a dominant causative agent of lethal outbreaks of vibriosis in many marine species (3)(4)(5)(6). For example, the embryonic oyster is vulnerable to vibriosis, which causes massive mortality of larvae and thus heavy losses to the aquaculture industry (7)(8)(9).…”

“…Increasingly, economic casualties and health risks annually brought about by these pathogenic bacteria have aroused global concerns. In recent years, research on the pathogenic mechanisms of V. alginolyticus has gained momentum, which enables the identification of some key virulence factors including polar and lateral flagella, hemolysins, alternative sigma factor RpoX, outer membrane protein A (OmpA), type III secretion system, and so on (3,10,11). Among this, type III secretion system (T3SS) of V. alginolyticus has emerged as an important virulence determinant, whereby variable effectors are directly translocated into the host cytosol for manipulating cellular responses (10,(12)(13)(14).…”