• Fisheries and Aquatic Sciences
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• 제15권1호
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• pp.83-89
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• 2012

Flavobacterium johnsoniae was isolated from farmed rainbow trout Oncorhynchus mykiss in Korea, and its biochemical and molecular characterization was determined. Yellow-pigmented bacterial colonies were isolated from 18 of 64 fish samples (28.1%) on trypticase soy agar plates, and their biochemical profiles were characterized by API 20E and API 20NE test kits. F. johnsoniae was identified by biochemical phenotyping of factors including rapid gliding motility, Gram-negative condition, oxidase- and catalase-positive status, Congo red absorption, nitrate reduction, ${\beta}$-galactosidase production, acid production from glucose, and gelatin and casein hydrolysis. PCR and subsequent sequencing of 16S rRNA confirmed that the yellow-pigmented colonies were most similar to F. johnsoniae. The alignment analysis of 16S rRNA sequences also showed that all 18 rainbow trout isolates had highly similar homologies (97-99% identity). One isolate was selected and named FjRt09. This isolate showed 98% homology with previously reported F. johnsoniae isolates, and in phylogenetic analysis was more closely grouped with F. johnsoniae than with F. psychrophilum, F. columnare, or F. branchiophilum. This is the first report on the occurrence and biochemical characterization of F. johnsoniae isolated from rainbow trout in Korea.

• Journal of Ginseng Research
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• 제36권4호
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• pp.418-424
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• 2012

This study focused on the enzymatic biotransformation of the major ginsenoside Rb1 into Rd for the mass production of minor ginsenosides using a novel recombinant ${\beta}$-glucosidase from Flavobacterium johnsoniae. The gene (bglF3) consisting of 2,235 bp (744 amino acid residues) was cloned and the recombinant enzyme overexpressed in Escherichia coli BL21(DE3) was characterized. This enzyme could transform ginsenoside Rb1 and gypenoside XVII to the ginsenosides Rd and F2, respectively. The glutathione S-transferase (GST) fused BglF3 was purified with GST-bind agarose resin and characterized. The kinetic parameters for ${\beta}$-glucosidase had apparent $K_m$ values of $0.91{\pm}0.02$ and $2.84{\pm}0.05$ mM and $V_{max}$ values of $5.75{\pm}0.12$ and $0.71{\pm}0.01{\mu}mol{\cdot}min^{-1}{\cdot}mg$ of $protein^{-1}$ against p-nitrophenyl-${\beta}$-D-glucopyranoside and Rb1, respectively. At optimal conditions of pH 6.0 and $37^{\circ}C$, BglF3 could only hydrolyze the outer glucose moiety of ginsenoside Rb1 and gypenoside XVII at the C-20 position of aglycon into ginsenosides Rd and F2, respectively. These results indicate that the recombinant BglF3 could be useful for the mass production of ginsenosides Rd and F2 in the pharmaceutical or cosmetic industry.

• 미생물학회지
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• 제45권1호
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• pp.74-81
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• 2009

2007년 7월부터 12월까지 총 5회 전라북도 군산에 위치한 초등학교의 정수기 물을 대상으로 미생물학적 수질에 대하여 조사하였다. 조사기간 중 정수기 물의 종속영양세균의 분포는 $0{\sim}1.2{\pm}0.2{\times}10^4CFU/ml$의 범주에서 나타났는데, 이 중 최대값은 우리나라 먹는 물 수질기준을 120배 초과하는 값을 나타냈다. 월별 수질기준을 초과하는 정수기 물의 백분율은 7월과 9월에 90%, 10월과 11월에 87.2%, 12월에 93.7%로 조사되었다. 한편 총대장균군과 병원성 세균인 Salmonella와 Shigella는 정수기 물과 수돗물에서 모두 검출되지 않았다. 총 5회의 실험 중 정수기 물에서 분리한 세균을 분자생물학적인 방법으로 동정한 결과, Sphingomonas, Methylobacterium, Caulobacter, Novosphingobium, Bosea, Brevundimonas, Aminobacter, Ralstonia, Mitsuaria, Variovorax, Acidovorax, Massilia, Pseudomonas, Acinetobacter, Aeromonas, Bacillus, Staphylococcus, Brevibacillus, Microbacterium, Lapillicoccus, Micrococcus, Arthrobacter, Janibacter, Flavobacterium, Chryseobacterium, Hymenobacter 등 26개 속이 동정되었다. 검출된 세균의 대부분은 일반 환경에서 다량 존재하는 세균들로서 병원성이 없으나, Pseudomonas fluorescens, Staphylococcus epidermidis, Flavobacterium johnsoniae, Acinetobacter johnsonii 등은 기회감염균으로 면역력이 낮은 초등학교 학생들의 경우 감염의 가능성이 있다.

• Journal of Ginseng Research
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• 제42권4호
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• pp.412-418
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• 2018

Background: Ginsenoside Rg3(S) and compound K (C-K) are pharmacologically active components of ginseng that promote human health and improve quality of life. The aim of this study was to produce Rg3(S) and C-K from ginseng extract using recombinant Lactococcus lactis. Methods: L. lactis subsp. cremoris NZ9000 (L. lactis NZ9000), which harbors ${\beta}$-glucosidase genes (BglPm and BglBX10) from Paenibacillus mucilaginosus and Flavobacterium johnsoniae, respectively, was reacted with ginseng extract (protopanaxadiol-type ginsenoside mixture). Results: Crude enzyme activity of BglBX10 values comprised 0.001 unit/mL and 0.003 unit/mL in uninduced and induced preparations, respectively. When whole cells of L. lactis harboring pNZBglBX10 were treated with ginseng extract, after permeabilization of cells by xylene, Rb1 and Rd were converted into Rg3(S) with a conversion yield of 61%. C-K was also produced by sequential reactions of the permeabilized cells harboring each pNZBgl and pNZBglBX10, resulting in a 70% maximum conversion yield. Conclusion: This study demonstrates that the lactic acid bacteria having specific ${\beta}$-glucosidase activity can be used to enhance the health benefits of Panax ginseng in either fermented foods or bioconversion processes.