Journal of Microbiology

Journal Article

The type II histidine triad protein HtpsC facilitates invasion of epithelial cells by highly virulent Streptococcus suis serotype 2: Yunjun Lu , Shu Li , Xiaodong Shen , Yan Zhao , Dongming Zhou , Dan Hu , Xushen Cai , Lixia Lu , Xiaohui Xiong , Ming Li , Min Cao; J. Microbiol. 2021;59(10):949-957. Published online September 7, 2021; DOI: https://doi.org/10.1007/s12275-021-1129-1

Abstract: Streptococcus suis serotype 2 (S. suis 2) is an important zoonotic pathogen that presents a significant threat both to pigs and to workers in the pork industry. The initial steps of S. suis 2 pathogenesis are unclear. In this study, we found that the type II histidine triad protein HtpsC from the highly virulent Chinese isolate 05ZYH33 is structurally similar to internalin A (InlA) from Listeria monocytogenes, which plays an important role in mediating listerial invasion of epithelial cells. To determine if HtpsC and InlA function similarly, an isogenic htpsC mutant (ΔhtpsC) was generated in S. suis by homologous recombination. The htpsC deletion strain exhibited a diminished ability to adhere to and invade epithelial cells from different sources. Double immunofluorescence microscopy also revealed reduced survival of the ΔhtpsC mutant after cocultivation with epithelium. Adhesion to epithelium and invasion by the wild type strain was inhibited by a monoclonal antibody against E-cadherin. In contrast, the htpsC-deficient mutant was unaffected by the same treatment, suggesting that E-cadherin is the host-cell receptor that interacts with HtpsC and facilitates bacterial internalization. Based on these results, we propose that HtpsC is involved in the process by which S. suis 2 penetrates host epithelial cells, and that this protein is an important virulence factor associated with cell adhesion and invasion.

Research Support, Non-U.S. Gov't

Establishment and Characterization of the Epithelioma Papulosum Cyprini (EPC) Cell Line Persistently Infected with Infectious Pancreatic Necrosis Virus (IPNV), an Aquabirnavirus: Hyoung Jun Kim , Jae-Kwon Cho , Hyung-Kyu Hwang , Myung-Joo Oh , Toyohiko Nishizawa; J. Microbiol. 2012;50(5):821-826. Published online November 4, 2012; DOI: https://doi.org/10.1007/s12275-012-2364-2

Abstract: Infectious pancreatic necrosis virus (IPNV), a type species of aquabirnaviruses in the family Birnaviridae, is an etiological agent of infectious pancreatic necrosis and has been isolated from epizootics of cultured salmonids. In the present study, an epithelioma papulosum cyprini (EPC) cell line persistently infected with IPNV (PI-EPC) was experimentally established by subculturing EPC cells surviving IPNV infection, and was characterized. PI-EPC cells were morphologically indistinguishable from EPC, but continued to grow and yield IPNV. PI-EPC cells showed no cytopathic effect due to IPNV inoculation, and susceptibility of PI-EPC cells against heterologous viruses was not different from that of EPC cells. Only one cell of 103.5 PI-EPC cells produced IPNV at approximately 100.5 50% tissue culture infectious dose (TCID50)/cell/day, which was approximately 1,000 times lower than that of normal EPC cells. PI-EPC cells that did not yield IPNV (N-PI-EPC) were screened. The IPNV genome was detected from both PI-EPC and N-PI-EPC cells, and the IPNV VP2 structural protein was detected from both cell lines, but no other IPNV proteins were observed by Western blot analysis with anti-IPNV serum. Thus, multiplication of IPNV in PI-EPC cells was regulated by some host cell factors, except interferon.

Chemical Midification of Purin Nucleoside Phosphorulase in Serratia marcescens: Choi , Hye Seon; J. Microbiol. 1998;36(2):74-79.

Abstract: Serratia marcescens purine nucleoside phosphorylase (PNP) has been purified and characterized. The physical and kinetic properties have been previously described(Choi, H.S. 1998. Biosci. Biotechnol. Biochem. 62, 667-671). Chemical modification of the enzyme was attempted to gain insight on the active site. The enzyme was inactivated in a time dependent manner by phenylglyoxal or diethylpyrocarbonate (DEPC). There was a linear relationship between the observed rate of inactivation and the phenylglyoxal or DEPC concentration. At 30℃ the bimolecular rate constant for the modification was 0.22 mM^-1 min^-1 in 50 mM NaHCO_3 buffer, pH 7.5, for phenylglyoxal and 1.33 mM^-1min^-1 in 50 mM sodium cotrate, pH 6.0, for DEPC. Preincubation with saturated solutions of substrates protected the enzyme from inhibition by kphenylglyoxal and DEPC, indicating that reactions with these reagents were directed at arginyl and histidyl residues, respectively, which are essential for the catalytic function of the enzyme.

Search