Journal of Microbiology

Jung-Wan Kim

4 Articles

Characterization of a cold-adapted debranching enzyme and its role in glycogen metabolism and virulence of Vibrio vulnificus MO6-24/O: Ah-Reum Han , Haeyoung Kim , Jong-Tae Park , Jung-Wan Kim; J. Microbiol. 2022;60(4):375-386. Published online February 14, 2022; DOI: https://doi.org/10.1007/s12275-022-1507-3

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Vibrio vulnificus MO6-24/O has three genes annotated as debranching enzymes or pullulanase genes. Among them, the gene encoded by VVMO6_03032 (vvde1) shares a higher similarity at the amino acid sequence level to the glycogen debranching enzymes, AmyX of Bacillus subtilis (40.5%) and GlgX of Escherichia coli (55.5%), than those encoded by the other two genes. The vvde1 gene encoded a protein with a molecular mass of 75.56 kDa and purified Vvde1 efficiently hydrolyzed glycogen and pullulan to shorter chains of maltodextrin and maltotriose (G3), respectively. However, it hydrolyzed amylopectin and soluble starch far less efficiently, and β-cyclodextrin (β-CD) only rarely. The optimal pH and temperature of Vvde1 was 6.5 and 25°C, respectively. Vvde1 was a cold-adapted debranching enzyme with more than 60% residual activity at 5°C. It could maintain stability for 2 days at 25°C and 1 day at 35°C, but it destabilized drastically at 40°C. The Vvde1 activity was inhibited considerably by Cu2+, Hg2+, and Zn2+, while it was slightly enhanced by Co2+, Ca2+, Ni2+, and Fe2+. The vvde1 knock-out mutant accumulated more glycogen than the wild-type in media supplemented with 1.0% maltodextrin; however, the side chain length distribution of glycogen was similar to that of the wild-type except G3, which was much more abundant in the mutant. Therefore, Vvde1 seemed to debranch glycogen with the degree of polymerization 3 (DP3) as the specific target branch length. Virulence of the pathogen against Caenorhabditis elegans was attenuated significantly by the vvde1 mutation. These results suggest that Vvde1 might be a unique glycogen debranching enzyme that is involved in both glycogen utilization and shaping of glycogen molecules, and contributes toward virulence of the pathogen.

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Characterization of glycogen-related glycoside hydrolase glgX and glgB from Klebsiella pneumoniae and their roles in biofilm formation and virulence
Xinyue Liu, Jialin Li, Ruibing Wu, Liping Bai
Frontiers in Cellular and Infection Microbiology.2024;[Epub] CrossRef
Function of the mdxR gene encoding a novel regulator for carbohydrate metabolism and sporulation in Bacillus subtilis 168
Tianshi Wang, Jung-Wan Kim
Archives of Microbiology.2023;[Epub] CrossRef
Identification of a novel cyclomaltodextrinase annotated as a neopullulanase in the genome of Bacillus cereus
Bo-Ram Park, Davoodbasha MubarakAli, Jung-Wan Kim
Archives of Microbiology.2023;[Epub] CrossRef
Functional conservation of specialized ribosomes bearing genome-encoded variant rRNAs in Vibrio species
Younkyung Choi, Eunkyoung Shin, Minho Lee, Ji-Hyun Yeom, Kangseok Lee, Bashir Sajo Mienda
PLOS ONE.2023; 18(12): e0289072. CrossRef
Functional characterization of maltodextrin glucosidase for maltodextrin and glycogen metabolism in Vibrio vulnificus MO6-24/O
Hye-Young Kim, MubarakAli Davoodbasha, Jung-Wan Kim
Archives of Microbiology.2022;[Epub] CrossRef

Phosphate and Carbon Source Regulation of Alkaline Phosphatase and Phospholipase in Vibrio vulnificus: Wan-Seok Oh , Young-Sun Im , Kyu-Young Yeon , Young-Jun Yoon , Jung-Wan Kim; J. Microbiol. 2007;45(4):311-317.; DOI: https://doi.org/2567 [pii]

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Abstract PDF: In this study, the effects of phosphate concentration and carbon source on the patterns of alkaline phosphatase (APase) and phospholipase (PLase) expression in Vibrio vulnificus ATCC 29307 were assessed under various conditions. The activities of these enzymes were repressed by excess phosphate (4 mM) in the culture medium, but this repression was reversed upon the onset of phosphate starvation in low phosphate defined medium (LPDM) containing 0.2 mM of phosphate at approximately the end of the exponential growth phase. The expressions of the two enzymes were also influenced by different carbon sources, including glucose, fructose, maltose, glycerol, and sodium acetate at different levels. The APase activity was derepressed most profoundly in LPDM containing fructose as a sole carbon source. However, the repression/derepression of the enzyme by phosphate was not observed in media containing glycerol or sodium acetate. In LPDM-glycerol or sodium acetate, the growth rate was quite low. The highest levels of PLase activity were detected in LPDMsodium acetate, followed by LPDM-fructose. PLase was not fully repressed by high phosphate concentrations when sodium acetate was utilized as the sole carbon source. These results showed that multiple regulatory systems, including the phosphate regulon, may perform a function in the expression of both or either APase and PLC, in the broader context of the survival of V. vulnificus.

Expression of the Promoter for the Maltogenic Amylase Gene in Bacillus subtilis 168: Do-Yeon Kim , Choon-Hwan Cha , Wan-Seok Oh , Young-Jun Yoon , Jung-Wan Kim; J. Microbiol. 2004;42(4):319-327.; DOI: https://doi.org/2104 [pii]

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Abstract PDF: An additional amylase, besides the typical a-amylase, was detected for the first time in the cytoplasm of B. subtilis SUH4-2, an isolate from Korean soil. The corresponding gene (bbmA) encoded a maltogenic amylase (MAase) and its sequence was almost identical to the yvdF gene of B. subtilis 168, whose function was unknown. Southern blot analysis using bbmA as the probe indicated that this gene was ubiquitous among various B. subtilis strains. In an effort to understand the physiological function of the bbmA gene in B. subtilis, the expression pattern of the gene was monitored by measuring the [beta]-galactosidase activity produced from the bbmA promoter fused to the amino terminus of the lacZ structural gene, which was then integrated into the amyE locus on the B. subtilis 168 chromosome. The promoter was induced during the mid-log phase and fully expressed at the early stationary phase in defined media containing [beta]-cyclodextrin ([beta]-CD), maltose, or starch. On the other hand, it was kept repressed in the presence of glucose, fructose, sucrose, or glycerol, suggesting that catabolite repression might be involved in the expression of the gene. Production of the [beta]-CD hydrolyzing activity was impaired by the spo0A mutation in B. subtilis 168, indicating the involvement of an additional regulatory system exerting control on the promoter. Inactivation of yvdF resulted in a significant decrease of the [beta]-CD hydrolyzing activity, if not all. This result implied the presence of an additional enzyme(s) that is capable of hydrolyzing [beta]-CD in B. subtilis 168. Based on the results, MAase encoded by bbmA is likely to be involved in maltose and [beta]-CD utilization when other sugars, which are readily usable as an energy source, are not available during the stationary phase.

Genotyping of Six Pathogenic Vibrio Species Based on RFLP of 16S rDNAs for Rapid Identification: Young-Jun Yoon , Kyung-Hwan Im , Young-Hwan Koh , Seong-Kon Kim , Jung-Wan Kim; J. Microbiol. 2003;41(4):312-319.

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Abstract PDF: In an attempt to develop a method for rapid and accurate identification of six Vibrio species that are clinically important and most frequently detected in Korea, 16S rDNA restriction fragment length polymorphism (RFLP) of Vibrio type strains, as well as environmental isolates obtained from the Korean coastal area, was analyzed using ten restriction endonucleases. Digestion of the 16S rDNA fragments amplified by polymerase chain reaction (PCR) with the enzymes gave rise to 2~6 restriction patterns for each digestion for 47 Vibrio strains and isolates. An additional 2~3 restriction patterns were observed for five reference species, including Escherichia coli, Aeromonas hydrophila, A. salmonicida, Photobacterium phosphoreum, and Plesiomonas shigelloides. A genetic distance tree based on RFLP of the bacterial species correlated well with that based on 16S rDNA sequences. The very small 16S rDNA sequence difference (0.1%) between V. alginolyticus and V. parahaemolyticus was resolved clearly by RFLP with a genetic distance of more than 2%. RFLP variation within a species was also detected in the cases of V. parahaemolyticus, V. proteolyticus, and V. vulnificus. According to the RFLP analysis, six Vibrio and five reference species were assigned to 12 genotypes. Using three restriction endonucleases to analyze RFLP proved sufficient to identify the six pathogenic Vibrio species.

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