Vibrio alginolyticus is one of the Vibrio pathogens common to humans and marine animals. During infection and induction of the host immune response, outer membrane proteins of bacteria play an important role. In this study, an outer membrane protein gene (ompW) was cloned from V. alginolyticus and expressed in Escherichia coli. The 645 bp open reading frame (ORF) encodes a protein of 214 amino acid residues with a predicted molecular weight of 23.3 kDa. The amino acid sequence showed a high identity with that of Photobacterium damselae (96.2%) and Vibrio parahaemolyticus (94.4%). The alignment analysis indicated that OmpW was highly conserved. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the gene was over-expressed in E. coli BL21(DE3). Western blot analysis revealed that the expressed protein had immunoreactivity. The recombinant protein was purified by affinity chromatography on Ni-NTA Superflow resin. Large yellow croaker vaccinated with the purified OmpW showed significantly increased antibody to OmpW, which could resist the infection by V. alginolyticus. A specific antibody was detected by enzyme-linked immunosorbent assay. This study suggested that the conserved OmpW could be an effective vaccine candidate against infection by V. alginolyticus.
Vibrio harveyi is a causative agent of vibriosis in the large yellow croaker Pseudosciaena crocea and causes severe losses to the aquaculture industry in China. The vaccines based on the outer membrane proteins (OMPs) of the pathogens are considered to be the optimum intervention for this disease. In this study, two V. harveyi OMP genes, OmpK* and glyceraldehyde-3-phosphate dehydrogenase (GAPDH*), were cloned, sequenced, and characterized. The recombinant proteins (r-OmpK and r-GAPDH) were expressed by the prokaryotic expression vector pET-30a(+) and purified with nickel-nitrilotriacetic acid affinity chromatography. Western blots showed that rabbit antisera against purified r-OmpK and r-GAPDH specifically reacted with the native OMP of V. harveyi. Large yellow croakers were immunized with r-OmpK and r-GAPDH. Specific antibody titer assessed by enzyme-linked immunosorbent and phagocytosis assays demonstrated that specific and innate immunity was stimulated in response to the OMPs of V. harveyi. Challenge results indicated that vaccination of large yellow croakers with r-OmpK and r-GAPDH increased relative survival (37.7% and 40.0%, respectively) against wild V. harveyi.
Antibiotic resistance in Helicobacter pylori has been growing worldwide with current treatment regimens. Development of new compounds for treatment of H. pylori infections is urgently required to achieve a successful eradication therapy in the future. Armeniaspirols, a novel class of natural products isolated from Streptomyces armeniacus, have been previously identified as antibacterial agents against Gram-positive pathogens. In this study, we found that armeniaspirol A (ARM1) exhibited potent antibacterial activity against H. pylori, including multidrug-resistant strains, with MIC range values of 4-16 lg ml -1 . The underlying mechanism of action of ARM1 against H. pylori involved the disruption of bacterial cell membranes. Also, ARM1 inhibited biofilm formation, eliminated preformed biofilms and killed biofilm-encased H. pylori in a dose-dependent manner. In a mouse model of multidrug-resistant H. pylori infection, dual therapy with ARM1 and omeprazole showed efficient in vivo killing efficacy comparable to the standard triple therapy, and induced negligible toxicity against normal tissues. Moreover, at acidic pH 2.5, ARM1 exhibited a much more potent anti-H. pylori activity than metronidazole. Thus, these findings demonstrated that ARM1 is a novel potent anti-H. pylori agent, which can be developed as a promising drug lead for treatment of H. pylori infections.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.