김병식 교수

Up to 95% of deaths from seafood-borne infections in the United States are due solely to one pathogen, V. vulnificus. Among its various virulence factors, the MARTX(Vv) toxin has been characterized as a critical exotoxin for successful pathogenesis of V. vulnificus in mouse infection models. Similarly to MARTX toxins of other pathogens, MARTX(Vv) toxin is comprised of repeat-containing regions, central effector domains, and an autoprocessing cysteine protease domain. Yet how each of these region

Pathogenic <i>Vibrio</i> species cause diseases in diverse marine animals reared in aquaculture. Since their pathogenesis, persistence, and survival in marine environments are regulated by quorum sensing (QS), QS interference has attracted attention as a means to control these bacteria in aquatic settings. A few QS inhibitors of <i>Vibrio</i> species have been reported, but detailed molecular mechanisms are lacking. Here, we identified a novel, potent, and selective <i>Vibrio</i> QS inhibitor, n

The marine bacterium <i>Vibrio vulnificus</i> causes food-borne diseases, which may lead to life-threatening septicemia in some individuals. Therefore, identifying virulence factors in <i>V. vulnificus</i> is of high priority. We performed a transcriptome analysis on <i>V. vulnificus</i> after infection of human intestinal HT29-methotrexate cells and found induction of <i>plpA</i>, encoding a putative phospholipase, <i>Vv</i>PlpA. Bioinformatics, biochemical, and genetic analyses demonstrated th

The opportunistic pathogen V. parahaemolyticus is a major causative agent for seafood-borne illness worldwide. It also causes severe vibriosis in aquaculture animals, affecting seafood production with huge economic loss. These issues are getting worse due to the current global warming in oceans, spread of antibiotic resistance, and changes in consumer preference toward ready-to-eat (RTE) food items including seafood. To answer the urgent need for sustainable biocontrol agents against V. parahaem

The nan cluster of Vibrio vulnificus, a food-borne pathogen, consists of two divergently transcribed operons, nanT(PSL)AR and nanEK nagA, required for transport and catabolism of N-acetylneuraminic acid (Neu5Ac). A mutation of nanR abolished the extensive lag phase observed for the bacteria growing on Neu5Ac and increased transcription of nanT(P) and nanE, suggesting that NanR is a transcriptional repressor of both nan operons. Intracellular accumulation of Neu5Ac was dependent on the carbon sou

Many Gram-negative bacterial pathogens directly deliver numerous effector proteins from the bacterium to the host cell, thereby altering the target cell physiology. The already well-characterized effector delivery systems are type III, type IV, and type VI secretion systems. Multifunctional autoprocessing repeats-in-toxin (MARTX) toxins are another effector delivery platform employed by some genera of Gram-negative bacteria. These single polypeptide exotoxins possess up to five effector domains

Vibrio vulnificus infects humans and causes lethal septicemia. The primary virulence factor is a multifunctional-autoprocessing repeats-in-toxin (MARTX) toxin consisting of conserved repeats-containing regions and various effector domains. Recent genomic analyses for the newly emerged V. vulnificus biotype 3 strain revealed that its MARTX toxin has two previously unknown effector domains. Herein, we characterized one of these domains, Domain X (DmXVv ). A structure-based homology search revealed

<i>Vibrio vulnificus</i> is an environmental organism that causes septic human infections characterized by high morbidity and mortality. The annual incidence and global distribution of this pathogen are increasing as ocean waters warm. Clinical strains exhibit variations in the primary virulence toxin, suggesting a potential for the emergence of new strains with altered virulence properties. A clonal outbreak of tilapia-associated wound infections in Israel serves as a natural experiment for the

Sialic acids consist of nine-carbon keto sugars that are commonly found at the terminal end of mucins. This positional feature of sialic acids contributes to host cell interactions but is also exploited by some pathogenic bacteria in evasion of host immune system. Moreover, many commensals and pathogens use sialic acids as an alternative energy source to survive within the mucus-covered host environments, such as the intestine, vagina, and oral cavity. Among the various biological events mediate

Here, we investigated the novel bacteriophage BCC348 and its endolysin LysBCC348 as alternative antimicrobials against the major foodborne pathogen Bacillus cereus . The Becedseptimavirus genus phage BCC348 effectively inhibited the growth of B. cereus ATCC 27348 with a remarkable burst size of ∼600 PFU/infected cell. The cation-dependent amidase endolysin LysBCC348 lysed the host B. cereus and Listeria monocytogenes and EDTA-treated Gram-negative pathogens. In a cold storage model of Korean ric

After invading a host, bacterial pathogens secrete diverse protein toxins to disrupt host defense systems. To ensure successful infection, however, pathogens must precisely regulate the expression of those exotoxins because uncontrolled toxin production squanders energy. Furthermore, inappropriate toxin secretion can trigger host immune responses that are detrimental to the invading pathogens. Therefore, bacterial pathogens use diverse transcriptional regulators to accurately regulate multiple e

To understand toxin-stimulated host-pathogen interactions, we performed dual-transcriptome sequencing experiments using human epithelial (HT-29) and differentiated THP-1 (dTHP-1) immune cells infected with the sepsis-causing pathogen <i>Vibrio vulnificus</i> (either the wild-type [WT] pathogen or a <u>m</u>ultifunctional-<u>a</u>utoprocessing <u>r</u>epeats-in-<u>t</u>o<u>x</u>in [MARTX] toxin-deficient strain). Gene set enrichment analyses revealed MARTX toxin-dependent responses, including neg