• 미생물학회지
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• 제19권4호
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• pp.179-185
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• 1981

한강 수계에서 SDBS (Sodium Dodecyl Benzene Sulfonate)를 유일한 탄소원으로 가지는 최소배지에서 서란 120 균주중 $4^{\circ}C$에서 생장이 좋은 8균주를 선택하여 동정하였으며. 이들의 온도에 따른 생장파 분해능을 흡광도 분석기를 이용하여 측정하였다. 동정 결과. Ps. fluorescens가 4균주, Ps. putida가 2균주 이었다. 이들중 Ps. fluorescens LP6, Ps. lido Lei, Ps. fluorescens LS 6의 비생장율은 모두 $25^{\circ}C$에서 가장 높은 값을 나타냈으나 정체기에서의 균체량은 $5^{\circ}C$ 에서 가장 높았다. 따라서 이들 3 균주는 faculfative psychrophilic bacteria로 사료된다. 한편 SDBS의 분해는 세포가 정체기에 들어가면서 시작되었으며, 분해능은 $25^{\circ}C$C에서 가장 좋았다.

• 한국환경보건학회지
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• 제19권2호
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• pp.10-15
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• 1993

Hygienic condition of farm waters has an effect on the hygiene of dairy foods. So we examined Standard Plate Count, coliform, E. coli, heat-resistant bacteria, psychrophilic bacteria, Pseudomonas aeruginosa and enterococcus for the bacterial sanitation of 78 farm waters in Kyunggi Province. Of the 78 farm waters, the average number of psychrophilic bacteria was 750 $\pm$ 170/ml, SPC 440 $\pm$ 130/ml, Pseudomonas aeruginosa 130 $\pm$ 97/100/ml, Coliform 22 $\pm$ 17/ml, E. coli 10 $\pm$ 6/100/ml, Heatresistant bacteria 5 $\pm$ 1ml, and Enterococcus 2 $\pm$ 1/100/ml. The percent of over than 1000/ml in SPC and psychrophilic bacteria of 78 farm water was 11.5% and 23.1%, respectively. The rate of over than 10/ml in coliform and heat-resistant bacteria was 12.8% and 15.4%, respectively and the rate of over than 10/100 ml in E. coli, Pseudomonas aeruginosa and enterococcus was 8.9%, 33.3%, and 2.6%, respectively. Pseudomonas aeruginosa was no significant between any other indicator organisms, and psychrophilic bacteria was significant with only SPC but other indicator organisms were highly significant with each other.

• Ocean and Polar Research
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• 제27권2호
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• pp.221-230
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• 2005

Recently there has been a rapid accumulation of knowledge of microbial life in cold and frozen ecosystems. This understanding has revealed the extensive diversity of psychrophilic prokaryotes. Cultivation-based and molecular-based surveys have been performed in Antarctic habitats ranging from glacial ice to continental shelf sediments. Results indicate that psychrophilic taxa permeate throughout the Bacteria while they represent a more mysterious element of diversity in the Archaea owing to a notable lack of cultured strains. In certain cold climate ecosystems the diversity of psychrophilic populations reach levels comparable to the richest temperate equivalents. Within these communities must exist tremendous genetic diversify that is potentially of fundamental and of practical value. So far this genetic pool has been hardly explored. Only recently have genomic data become available for various psychrophilic prokaryotes and more is required. This owes to the fact that psychrophilic microbes possess manifold mechanisms for cold adaptations, which not only Provide enhanced survival and Persistence but Probably also contributes to niche specialisation. These mechanisms, including cold-active and ice-active proteins, polyunsaturated lipids and exopolysaccharides also have a great interest to biotechnologists.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2647-2650
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• 2009

Cold shock proteins (Csps) are a subgroup of the cold-induced proteins on reduction of the growth temperature below the physiological temperature. They preferentially bind to single-stranded nucleic acids to translational regulation via RNA chaperoning. Csp plays important role in cold adaptations for the psychrophilic microorganism. Recently, Cold shock protein from psychrophilic bacteria, Colwellia psychrerythraea (CpCsp) has been identified. Three dimensional structures of a number of Csps from various microorganisms have been solved by NMR spectroscopy or X-ray crystallography, but structures of psychrophilic Csps were not studied yet. Therefore, cloning and purification protocols for further structural study of psychrophilic Csp have been optimized in this study. CpCsp was expressed in E. coli with pET-11a vector system and purified by ion exchange, size exclusion, and reverse phase chromatography. Expression and purification of CpCsp in M9 minimal media was carried out and $^{15}N$-labeled proteins with high purity over 90% was obtained. Further study will be carried out to investigate the tertiary structure and dynamics of CpCsp.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2410-2412
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• 2010

• 한국가정과학회지
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• 제5권2호
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• pp.45-54
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• 2002

Packaged Backsulgi cooked by steam/convection oven and then rapidly chilled was examined by research of microbiological test and sensory evaluation while storing them at the temperatures of 3$^{\circ}C$ and 3$0^{\circ}C$ for 0, 2, 4, 6, 10 days . The pH and reducing sugar content were seemed to change little at 3$^{\circ}C$. However the pH was rapidly reduced until 4 days and then decreased a little at 3$0^{\circ}C$, the reducing sugar content was inclosed little by little. In the microbiological test, any microbial growth in total aerobic, psychrophilic, anaerobic, spore forming bacteria, yeast and molds was not observed until 10 days at 3$^{\circ}C$, but microbial changes of aerobic, psychrophilic and anaerobic bacteria increased to 6 logCFU/g until 10 days at 3$0^{\circ}C$. However microbial changes of them decreased from 6 logCFU/g to 5 logCFU/g. As a result of the sensory evaluation, appearance, taste, color, softness, chewiness and overall Quality were significantly decreased during storage times(p<0.05), but scores of taste and overall quality on 6th days were 7.38${\pm}$1.06, 7.00${\pm}$0.93. Therefore we concluded that there was no problem about stability of storage 6 days at 3$^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2405-2409
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• 2011

The psychrophilic bacteria Psychromonas arctica survives at subzero temperatures by having adapted several protective mechanisms against freezing and oxidative stresses. Many reactive oxygen species are likely generated in P. arctica as a result of reduced metabolic turnover rates. A previous study identified the pasod gene for superoxide dismutase from P. arctica using a series of PCR amplifications. Here, upon cloning into a His-tag fused plasmid, the sod gene from P. arctica (pasod) was successfully expressed by IPTG induction. His-tagged PaSOD was subsequently purified by $Ni^{2+}$-NTA affinity chromatography. The purified PaSOD exhibited a higher SOD activity than that of Escherichia coli (EcSOD) at all temperatures. The difference in activity between PaSOD and EcSOD becomes even more significant at 4$^{\circ}C$, indicating that PaSOD plays a functional role in the cold adaptation of P. arctica in the Arctic.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1925-1930
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• 2011

Psychrophilic bacteria have acquired cold-resistance in order to protect themselves against freezing temperatures, which would otherwise be lethal. DnaK/DnaJ/GrpE systems are molecular chaperones which facilitate proper folding of newly synthesized proteins. Efficient folding processes are of great importance especially in a cold environment, such as the Arctic. In order to understand the protection mechanisms of psychrophilic bacteria against cold temperatures, we have explored a genome of KOPRI22215, tentatively identified as Psychromonas arctica, whose genome sequence has not yet been discovered. With an aim of searching for a coding gene of DnaK from KOPRI22215, we have applied a series of polymerase chain reactions (PCR) with homologous primers designed from other Psychromonas species and LA PCR in vitro cloning. 1917 bp complete coding sequence of dnaK from KOPRI22215 was identified including upstream promoter sites. Recombinant plasmids to overexpress PaDnaK along with EcDnaK (DnaK of E. coli) were then constructed in pAED4 vector and the pET-based system to induce PaDnaK expression by IPTG. Characterization assays of expressed PaDnaK were carried out by measuring survival rates upon 4 day incubation at 4 $^{\circ}C$: a refolding assay as molecular chaperone, and ATPase assay for functional activity. Taking account of all the data together, we conclude that PaDnaK was identified, successfully expressed, and found to be more efficient in providing cold-resistance for bacterial cells.

• 한국식품과학회지
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• 제34권5호
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• pp.927-930
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• 2002

시금치를 한국 식단의 식자재로 사용하기 위해 cook-chill 가공과 sous vide 기술을 사용하였다. 시금치는 500 g 단위로 차단성 필름을 사용하여 진공포장하고 Listeria monocytogenes의 6D 사멸조건에서 저온살균하고 $3^{\circ}C$에서 급속히 냉각한 다음 $3^{\circ}C$와 $10^{\circ}C$에서 저장하면서 품질을 측정하였다. 오염지표균은 중온성세균, 저온성세균, 혐기성세균, 내열성세균, 대장균군, 효모 및 곰팡이, Enterobacteriacea 및 분원성연쇄상구균을 측정하였다. 원료 시금치에서는 $2.2{\times}10^8\;cfu/g$로 높은 분포를 보였고, cook-chill 가공 후에는 $6.0{\times}10^3\;cfu/g$로 감소하였으며 저장기간 동안 서서히 증가하였다. 저온성세균과 혐기성세균은 거의 같은 양상을 보였으며, 효모 및 곰팡이, 대장균군, 분원성연쇄상구균 및 Enterobacteriacea는 cook-chill 가공 후에는 검출되지 않았다. 그람음성의 병원성세균은 Aeromonas hydrophila, Escherichia coli O157:H7, Plesiomonas shigelloides, Pseudomonas aeruginosa, Salmonella spp., Shigella spp., Yersinia enterocolitica, 그람양성균은 Bacillus cereus, Campylococcus spp., Clostridium perfringens, Listeria monocytogenes, Staphylococcus aureus을 분리시험하였다. A. hydrophila는 수세한 시금치에서 분리되었으나, 원료 시금치와 cook-chill한 시금치에서는 분리되지 않았다. B. cereus와 C. perfringens는 원료 시금치, 수세한 시금치와 cook-chill 가공한 시금치에서 분리된 반면 S. aureus는 원료 시금치와 수세한 시금치에서만 분리되었다. 그 외의 다른 병원성세균은 cook-chill 과정에서 분리되지 않았다.

• 한국수산과학회지
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• 제28권4호
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• pp.401-411
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• 1995

일본의 Sagami bay와 Suruga bay의 810-4,000m되는 심해에서 채취한 시료에서 Flavvobacterium sp., Pseudomonas sp., Vibrio sp. 균종을 분리하였다. 이들 중 barophilic과 psychrophilic bacteria인 sp.-86과 sp.-87를 분리동정하고 압력단계별 성장속도를 조사한 결과 400기압에서도 잘 성장하였고 특히 100기압에서 가장 성장속도가 좋았다. 균의 형태는 1기압의 균 형태에 비하여 400기압에서 성장한 간균이 30-50배 이상 긴 간균 형태였으나(Fig. 3), 다시 1기압에 방치하면 단간균으로 균괴(flock)를 형성한다(Fig. 4) 이들 균의 발육온도 범위는 $5-37^{\circ}C$까지 발육하며, NaCl 농도의 범위는 sp.-86은 $0.5-9\%$이고 최적성장 농도가 $3\%$, sp.-87 균주의 지방산 조성은 $C_{20-22}\;C_{16:1},\;C_{16:0}$ 순으로 높은 함량이었고 400기압에서는 $C_{18:1}\;C_{18:0},\;C_{20-22:0}$ 의 함량순을 보였다. sp.-87균주는 $C_{16:1}\;C_{14:0},\;C_{20-22:0}$의 순이었고 400기압에서는 $C_{14:1}\;C_{12:0},\;C_{16:1}$의의 순으로 함량조성이 변하였다. 아미노산 조성은 sp.-86의 깅우 aspartic acid, methionine, glutamic acid 함량순이었고 400기압에서는methionine, glutamic acid, aspartic acid 함량순이었다. sp.-87의 균주는 methionine, glutamic acid, aspratic acid 순이었고 400기압에서는 methionine이 가장 높은 함량이고 glutamic acid, isoleucine 순으로 높은 함량이었다.