• Journal of Microbiology and Biotechnology
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• 제33권8호
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• pp.992-997
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• 2023

Ferroptosis is a new kind of programmed cell death of which occurrence in microorganisms is not clearly verified. The elevated level of reactive oxygen species (ROS) influences cellular metabolisms through highly reactive hydroxyl radical formation under the iron-dependent Fenton reaction. Iron contributes to ROS production and acts as a cofactor for lipoxygenase to catalyze poly unsaturated fatty acid (PUFA) oxidation, exerting oxidative damage in cells. While ferroptosis is known to take place only in mammalian cells, recent studies discovered the possible ferroptosis-like death in few specific microorganisms. Capacity of integrating PUFA into intracellular membrane phospholipid has been considered as a key factor in bacterial or fungal ferroptosis-like death. Vibrio species in bacteria and Saccharomyces cerevisiae in fungi exhibited certain characteristics. Therefore, this review focus on introducing the occurrence of ferroptosis-like death in microorganisms and investigating the mode of action underlying the cells based on contribution of lipid peroxidation and iron-dependent reaction.

• 한국식품과학회지
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• 제37권4호
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• pp.611-617
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• 2005

본 연구에서는 E. coli. Salmonella, Shigella, Vibrio 등 4속의 주요 식중독유발 그람 음성 세균들을 대상으로 반복성 염기서열인 REP DNA sequence를 응용한 REP-PCR을 실시하였다. 이전의 보고에서 이들 4속의 식중독 유발세균 중 각각 혹은 일부를 대상으로 반복성 염기서열을 이용한 PCR을 적용한 사례는 있지만 그때 적용한 primer, PCR 반응조건 및 전기영동조건 등이 다양하였다. 그러므로 본 연구에서는 이와같은 4속의 세균들에 대하여 최적화된 동일한 primer와 PCR 반응조건 및 전기영동조건을 표준조건으로서 적용하였다. 그 결과로서 모든 4속의 식중독 세균 균주마다 REP-PCR 후 생성되는 fingerprinting pattern에서 속마다 1-3개의 공통적이며 독특한 band가 생성되는 것이 확인되어 이러한 pattern을 이용한 속 수준의 분리 동정과 그와 같은 주요 band들 이외의 부수적인 band들을 고려하여 종 수준까지의 분리도 가능함을 확인하였다. 따라서 본 연구를 통하여 반복적 DNA 염기서열을 이용한 REP-PCR이 주요 식중독 세균의 분리 동정 방법으로 사용될 수 있음을 확인하였다. 또한 본 연구를 통하여 얻은 결과는 더 많은 속(genus)의 식중독세균을 대상으로 한 새로운 분리 동정 방법을 확립하기 위하여 사용될 수 있을 것이다.

• Journal of Species Research
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• 제7권1호
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• pp.24-35
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• 2018

During a series of extensive surveys of prokaryotic species diversity in Korea, bacterial strains belonging to Gammaproteobacteria were isolated from various sources of aquatic and terrestrial environments. A total of 39 isolates were obtained, which represented 39 unrecorded species in Korea belonging to 20 genera in 12 families. Enterobacteriaceae was the largest family, as eight species were assigned, which was followed by Moraxellaceae (6 species) and Pseudomonadaceae (5 species). At the genus level, Marinobacter (6 species), and Pseudomonas (5 species) were the main genera, and at least two species were obtained for Acinetobacter (3 species), Psychrobacter (3 species), Shewanella (2 species), Dickeya (2 species), Salinivibrio (2 species), Vibrio (2 species) and Rhodanobacter(2 species). The detailed description of each unrecorded species is provided.

• 한국수산과학회지
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• 제34권5호
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• pp.430-434
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• 2001

미세조류 증식 저해균 Shewanella sp. SR-14와 연안해역에서 우점종으로 분포하는 세균인 Vibrio alginolyticus가 규조, Chaetoceros calcitrans의 증식에 미치는 영향 그리고 V. ajginolyticus가 Shewanella sp. SR-14의 C. calcitrans 증식저해 활성에 미치는 영향을 혼합배양으로 측정하였다. Shewsnella sp. SR-14와 해수에서 분리한 V. alginolyticus는 미세조류 배양용 무기배지에서 단독 또는 혼합 배양하여도 잘 증식하였으며, C. calcitrans와 혼합배양시 Shewanella sp. SR-14는 조류증식을 저해한 반면 V alginolyticus는 이 조류의 증식을 촉진하였다. 조류가 첨가된 배지에 Shewanella sp. SR-14의 최초 접종균수가 V. alginolyticus와 거의 같거나 1 log 정도 적게 접종되었을 때에는 C. calcitrans에 대한 Shewanella sp. SR-14의 증식 저해활성이 유지되었으나 V. alginolricus의 최초균수가 Shewanella sp. SR-14보다 3 log 이상 많았을 때에는 조류증식 저해활성이 나타나지 않았다.

• 한국수산과학회지
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• 제12권1호
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• pp.19-26
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• 1979

패류에서 저온성 대장균군의 위생학적 의의 및 패류의 위상상태를 평가하기 위한 자료를 얻고자 1978년 1월부터 12월까지 매월 참굴, 바지락, 홍합, 고막을 시료로하여 실험한 결과를 요약하면 다음과 같다. 1. 균수의 범위는 생균수가 $1.3\times10^3-2.5\times10^6/g$, 대장균군이 $>\~5.5\times10^2/g$, E. coli MPN이 $2\~9$. $2\times10^2/100g$으로 생균수는 4월에서 10월사이에는 대부분의 시료에서 패류의 위생학적 기준치를 초과하였고 E. coli 최확수도 7검체에서 초과한 것으로 나타났다. 2. 대장균군 373균주중 298균주가 분류동정되었고 이 가운데서 E. coli 1이 138균주$(46\%)$, K. aerogenes 1이 71균주$(46\%)$였다. 3. $5^{\circ}C$에서 발육가능한 저온성 대장균군은 분리균 373균주중에서 186균주로 $50\%$였다. 4. 세균 flora는 분리균 453균주 가운데서 Vibrio가 240균주$(53\%)$, Pseudomonas가 91균주$(20\%)$로 이들 2균속이 우세한 세균류를 구성하고 있었다. 5. 세균류의 계절적 변동은 Vibrio가 5월에서 10월사이 분포도가 높은 경향을 나타냈고 Moraxella 동계아만 검출되었으며 그 외의 균속은 큰 변동이 보이지 않았다. (본 연구는 1977년도 문교부 학술연구 조성비에 의한 것임).

• 대한임상검사과학회지
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• 제36권2호
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• pp.69-75
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• 2004

Vibrio vulnificus is a halophilic bacterium frequently involved in human infection of seafood-associated primary septicemia and primary wound infection, mostly in men with over 40-years of age with underlying liver disease. The primary septicemia, which is the most common form of V. vulnificus infection in Korea, is defined as a systemic illness presenting fever or hypotension with recovery of V. vulnificus from blood or tissue without the apparent primary focus of infection. V. vulnificus typically do not produce acid from sucrose, but a case of primary septisemia was found in a patient at Chonnam K hospital in 1993 from whose blood a sucrose-fermenting strain was isolated. The patient was a 62-year-old man, heavy drinker, with underlying liver disease. He consumed a raw seafood dish two days before onset of the present illness. His symptoms were tenderness and swelling on the right foot. He rapidly developed septicemia, resulting in sudden death. V. vulnificus was isolated from the venous blood culture of the patient. On subculture, the isolate formed yellow colonies on TCBS and produced acid from sucrose. Because of these characteristics, species identification was not achieved by the API 20E and was delayed. Other characteristics of the isolate were identical to those of typical V. vulnificus. The isolate was common serotype O4A and possession of V. vulnificus-specific cytolysin gene was detected by PCR. The isolate was susceptible to all the antimicrobial agents tested including tetracycline, but was intermediate to colistin. In conclusion, it is important that microbiologists be aware of the presence of sucrose-positive V. vulnificus when he or she identifies gram-negative bacilli, which is isolated from the blood of patients with a recent history of raw seafood dish consumption.

• 한국임상수의학회지
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• 제34권4호
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• pp.261-267
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• 2017

The aim of this study was to investigate the antibacterial properties of chitosan silver nanocomposites (CAgNCs) using pathogenic Vibrio ichthyoenteri as a bacterial model. Results of agar disc diffusion and turbidimetric assays showed that CAgNCs could inhibit the growth of V. ichthyoenteri in concentration dependent manner. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CAgNCs were 75 and $125{\mu}g/mL$, respectively. Furthermore, CAgNCs treatment induced the reactive oxygen species (ROS) level in V. ichthyoenteri cells in concentration and time dependent manner, suggesting that it generates oxidative stress, leading to bacterial cell death. The field emission scanning electron microscope (FE-SEM) images of CAgNCs treated V. ichthyoenteri exhibited strong cell membrane damage than un-treated control bacteria. MTT assay results showed the highest cell viability (22%) at $75{\mu}g/mL$ of CAgNCs treated bacteria samples. The results from this study suggest that CAgNCs is a potential antibacterial agent to control fish pathogenic bacteria.

• 대한미생물학회지
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• 제35권3호
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• pp.225-237
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• 2000

Vibrio vulnificus, a halophilic vibrio is an estuarine gram-negative bacteria that is associated with severe and frequently fatal wound infections and life-threatening septicemia. Bacteriocins are defined as antibacterial substance produced by various species of bacteria which are usually active against closely related organisms. Bacteriocins have found widespread application in epidemiological studies as specific markers of bacteria. It was proposed by Ha et al. (1990. J. Korean. Soc. Microbiol. 25: 586.) to give the bacteriocins produced by V. vulnificus the name "vulnificins". In the present study, a total of 72 strains of V. vulnificus isolated from patients and oysters were subjected to screen potential producers and indicators of vulnificin, applying ultraviolet induction method. Sensitivity of several strains of Serratia marcesans, Pseudomonas aeruginosa, Shigella flexneri, Salmonella typhi and Yersinia enterocolitica to vulnificins were also examined out. All the tested strains of V. vulnificus produced vulnificins active against indicator strains with various different inhibitory patterns. The spectrum of vulnificin activity and sensitive spectrum of indicator strains were considerably broad. Interestingly, almost all strains of S. marcescens, P. aeruginosa, Salmonella sp., Shigella sp. and Y. enterocolitica tested were sensitive to 1-7 vulnificin(s). Taken together, the present study demonstrated that all of the isolates of V. vulnificus produced vulnificins and that 8 good vulnificin producers and 10 good indicators were detected. These strains can be employed efficiently for establishing vulnificin typing scheme of V. vulnificus and for the detection of bacteriocinogeny and sensitivity in V. vulnificus. Biological role of vulnificin remains to be further elucidated.

• Journal of Microbiology and Biotechnology
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• 제31권5호
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• pp.756-763
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• 2021

Agarose is a linear polysaccharide composed of ᴅ-galactose and 3,6-anhydro-ʟ-galactose (AHG). It is a major component of the red algal cell wall and is gaining attention as an abundant marine biomass. However, the inability to ferment AHG is considered an obstacle in the large-scale use of agarose and could be addressed by understanding AHG catabolism in agarolytic microorganisms. Since AHG catabolism was uniquely confirmed in Vibrio sp. EJY3, a gram-negative marine bacterial species, we investigated AHG metabolism in Streptomyces coelicolor A3(2), an agarolytic gram-positive soil bacterium. Based on genomic data, the SCO3486 protein (492 amino acids) and the SCO3480 protein (361 amino acids) of S. coelicolor A3(2) showed identity with H2IFE7.1 (40% identity) encoding AHG dehydrogenase and H2IFX0.1 (42% identity) encoding 3,6-anhydro-ʟ-galactonate cycloisomerase, respectively, which are involved in the initial catabolism of AHG in Vibrio sp. EJY3. Thin layer chromatography and mass spectrometry of the bioconversion products catalyzed by recombinant SCO3486 and SCO3480 proteins, revealed that SCO3486 is an AHG dehydrogenase that oxidizes AHG to 3,6-anhydro-ʟ-galactonate, and SCO3480 is a 3,6-anhydro-ʟ-galactonate cycloisomerase that converts 3,6-anhydro-ʟ-galactonate to 2-keto-3-deoxygalactonate. SCO3486 showed maximum activity at pH 6.0 at 50℃, increased activity in the presence of iron ions, and activity against various aldehyde substrates, which is quite distinct from AHG-specific H2IFE7.1 in Vibrio sp. EJY3. Therefore, the catabolic pathway of AHG seems to be similar in most agar-degrading microorganisms, but the enzymes involved appear to be very diverse.

• Journal of Microbiology and Biotechnology
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• 제31권12호
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• pp.1672-1683
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• 2021

Vibrio parahaemolyticus is recognized as one of the most important foodborne pathogens responsible for gastroenteritis in humans. The bla_CARB-17 gene is an intrinsic β-lactamase gene and a novel species-specific genetic marker of V. parahaemolyticus. In this study, a loop-mediated isothermal amplification (LAMP) assay combined with a lateral flow dipstick (LFD) was developed targeting this bla_CARB-17 gene. The specificity of LAMP-LFD was ascertained by detecting V. parahaemolyticus ATCC 17802 and seven other non-V. parahaemolyticus strains. Finally, the practicability of LAMP-LFD was confirmed by detection with V. parahaemolyticus-contaminated samples and natural food samples. The results showed that the optimized reaction parameters of LAMP are as follows: 2.4 mmol/l Mg²⁺, 0.96 mmol/l dNTPs, 4.8 U Bst DNA polymerase, and an 8:1 ratio of inner primer to outer primer, at 63℃ for 40 min. The optimized reaction time of the LFD assay is 60 min. Cross-reactivity analysis with the seven non-V. parahaemolyticus strains showed that LAMP-LFD was exclusively specific for V. parahaemolyticus. The detection limit of LAMP-LFD for V. parahaemolyticus genomic DNA was 2.1 × 10^-4 ng/μl, corresponding to 630 fg/reaction and displaying a sensitivity that is 100-fold higher than that of conventional PCR. LAMP-LFD in a spiking study revealed a detection limit of approximately 6 CFU/ml, which was similar with conventional PCR. The developed LAMP-LFD specifically identified the 10 V. parahaemolyticus isolates from 30 seafood samples, suggesting that this LAMP-LFD may be a suitable diagnostic method for detecting V. parahaemolyticus in aquatic foods.