Journal of Microbiology

Host–microbial interactions in metabolic diseases: from diet to immunity: Ju-Hyung Lee , Joo-Hong Park; J. Microbiol. 2022;60(6):561-575. Published online May 5, 2022; DOI: https://doi.org/10.1007/s12275-022-2087-y

Abstract: Growing evidence suggests that the gut microbiome is an important contributor to metabolic diseases. Alterations in microbial communities are associated with changes in lipid metabolism, glucose homeostasis, intestinal barrier functions, and chronic inflammation, all of which can lead to metabolic disorders. Therefore, the gut microbiome may represent a novel therapeutic target for obesity, type 2 diabetes, and nonalcoholic fatty liver disease. This review discusses how gut microbes and their products affect metabolic diseases and outlines potential treatment approaches via manipulation of the gut microbiome. Increasing our understanding of the interactions between the gut microbiome and host metabolism may help restore the healthy symbiotic relationship between them.

NOTE] Isolation and Characterization of Histamine-Producing Bacteria from Fermented Fish Products: Jin Seok Moon , So-Young Kim , Kyung-Ju Cho , Seung-Joon Yang , Gun-Mook Yoon , Hyun-Ju Eom , Nam Soo Han; J. Microbiol. 2013;51(6):881-885. Published online December 19, 2013; DOI: https://doi.org/10.1007/s12275-013-3333-0

Abstract: Histamine is mainly produced by microorganisms that are found in fermented foods, and is frequently involved in food poisoning. Two histamine-producing bacteria were isolated from fermented fish products, anchovy sauce, and sand lance sauce by using a histidine decarboxylating medium. The species were identified as Bacillus licheniformis A7 and B. coagulans SL5. Multiplex PCR analysis showed the presence of the conserved histidine decarboxylase (hdc) gene in the chromosome of these bacteria. B. licheniformis A7 and B. coagulans SL5 produced the maximum amount of histamine (22.3±3.5 and 15.1±1.5 mg/L, respectively). As such, they were determined to be potential histamine-producing bacteria among the tested cultures.

Protein-Protein Interactions between Histidine Kinases and Response Regulators of Mycobacterium tuberculosis H37Rv: Ha-Na Lee , Kwang-Eun Jung , In-Jeong Ko , Hyung Suk Baik , Jeong-Il Oh; J. Microbiol. 2012;50(2):270-277. Published online April 27, 2012; DOI: https://doi.org/10.1007/s12275-012-2050-4

Abstract: Using yeast two-hybrid assay, we investigated protein-protein interactions between all orthologous histidine kinase (HK)/response regulator (RR) pairs of M. tuberculosis H37Rv and identified potential protein-protein interactions between a noncognate HK/RR pair, DosT/NarL. The protein interaction between DosT and NarL was verified by phosphotransfer reaction from DosT to NarL. Furthermore, we found that the DosT and DosS HKs, which share considerable sequence similarities to each other and form a twocomponent system with the DosR RR, have different crossinteraction capabilities with NarL: DosT interacted with NarL, while DosS did not. The dimerization domains of DosT and DosS were shown to be sufficient to confer specificity for DosR, and the different cross-interaction abilities of DosS and DosT with NarL were demonstrated to be attributable to variations in the amino acid sequences of the α2-helices of their dimerization domains.

Ligand-Receptor Recognition for Activation of Quorum Sensing in Staphylococcus aureus: Li-Chun Chen , Li-Tse Tsou , Feng-Jui Chen; J. Microbiol. 2009;47(5):572-581. Published online October 24, 2009; DOI: https://doi.org/10.1007/s12275-009-0004-2

Abstract: The accessory gene regulator (agr) locus controls many of the virulence toxins involved in Staphylococcus aureus pathogenesis, and can be divided into four specificity groups. AgrC is the only group-specific receptor to mediate both intra-group activation and inter-group inhibition. We studied the ligand-receptor recognition of the agr system in depth by using a luciferase reporter system to identify the key residues responsible for AgrC activation in two closely related agr groups, AgrC-I, and AgrC-IV. Fusion PCR and site-directed mutagenesis were used to screen for functional residues of AgrC. Our data suggest that for AgrC-IV activation, residue 101 is critical for activating the receptor. In contrast, the key residues for the activation of AgrC-I are located at residues 49~59, 107, and 116. However, three residue changes, T101A, V107S, I116S, are sufficient to convert the AIP recognizing specificity from AgrC-IV to AgrC-I.

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.

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