• Title/Summary/Keyword: Cold-adaptation

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Effect of Cold Adaptation on the Improved Viability of Lactobacillus crispatus KLB46 (Lactobacillus crispatus KLB46의 생균제제화를 위한 저온 전처리시 증지의 효과)

  • 김주현;이석용;장정은;김승철;윤현식;소재성
    • KSBB Journal
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    • v.16 no.6
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    • pp.626-631
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    • 2001
  • Lactobacilli have been considered to play important roles in the health of human vagina. They secrete inhibitory substances to prevent vaginal infection by pathogenic organisms. In a previous study, we have isolated several lactobacilli from Korean woman and one of them (KLB46) was selected and indentified as Lactobacillu crispatus which showed high antimicrobial activity. In this study. cold adaptation prior to subsequent stresses exposure was examined whether L. crispatus KLB46 maintain the viability better than the non-adapted calls under stresses. For pharmaceutical formulation, the lyophilization process is required where stresses such as freezing/thawing and dehydration are routinely applied. Formulated L. crispatus KLB46 can be used for ecological treatment of bacterial vaginosis. The response of cold-adapted cells to other environmental stresses such as acid, heat, ethanol, NaCl, and H$_2$O$_2$ was also examined. The results showed that cold-adapted cells maintained higher survival rate compared with the non-adapted cells (freezing-thawing. 3-folds; dehydration: 3-folds; acid, 3-folds; heat, 10-folds). However, we did net observe any positive effect of cold adaptation on other stresses such as ethanol, NaCl and H$_2$O$_2$. When chloramphenicol was added during cold adaptation, adaptation effect was abolished. This confirms that de novo protein synthesis is necessary during the adaptation process. Moreover, we have identified cold shock protein homolog that codes for a major cold shock protein by PCR amplification using degenerate primers.

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Supercooling Pretreatment Improves the Shelf-Life of Freeze-Dried Leuconostoc mesenteroides WiKim32

  • Seul-Gi Jeong;In Seong Choi;Ho Myeong Kim;Ji Yoon Chang;Hae Woong Park
    • Journal of Microbiology and Biotechnology
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    • v.32 no.12
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    • pp.1599-1604
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    • 2022
  • Storage stability of freeze-dried lactic acid bacteria is a critical factor for their cost-effectiveness. Long-term storage of lactic acid bacteria enables microbial industry to reduce distribution costs. Herein, we investigated the effect of cold adaptation under supercooling conditions at -5℃ on the viability of Leuconostoc mesenteroides WiKim32 during the freeze-drying process and subsequent storage. Cold adaptation increased the thickness of exopolysaccharides (EPS) and improved the viability of freeze-dried Leu. mesenteroides WiKim32. Compared to non-adapted cells, cold-adapted cells showed a 35.4% increase in EPS thickness under supercooling conditions. The viability of EPS-hydrolyzed cells was lower than that of untreated cells, implying that EPS plays a role in protection during the freeze-drying process. Cold adaptation increased the storage stability of freeze-dried Leu. mesenteroides WiKim32. Fifty-six days after storage, the highest viability (71.3%) was achieved with cold adaptation at -5℃. When EPS-containing broth was added prior to the freeze-drying process, the viability further increased to 82.7%. These results imply that cold adaptation by supercooling pretreatment would be a good strategy for the long-term storage of Leu. mesenteroides WiKim32.

Cloning, Expression, and Characterization of a Cold-Adapted Shikimate Kinase from the Psychrophilic Bacterium Colwellia psychrerythraea 34H

  • Nugroho, Wahyu Sri Kunto;Kim, Dong-Woo;Han, Jong-Cheol;Hur, Young Baek;Nam, Soo-Wan;Kim, Hak Jun
    • Journal of Microbiology and Biotechnology
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    • v.26 no.12
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    • pp.2087-2097
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    • 2016
  • Most cold-adapted enzymes possess higher $K_m$ and $k_{cat}$ values than those of their mesophilic counterparts to maximize the reaction rate. This characteristic is often ascribed to a high structural flexibility and improved dynamics in the active site. However, this may be less convincing to cold-adapted metabolic enzymes, which work at substrate concentrations near $K_m$. In this respect, cold adaptation of a shikimate kinase (SK) in the shikimate pathway from psychrophilic Colwellia psychrerythraea (CpSK) was characterized by comparing it with a mesophilic Escherichia coli homolog (EcSK). The optimum temperatures for CpSK and EcSK activity were approximately $30^{\circ}C$ and $40^{\circ}C$, respectively. The melting points were $33^{\circ}C$ and $45^{\circ}C$ for CpSK and EcSK, respectively. The ${\Delta}G_{H_2O}$ (denaturation in the absence of denaturing agent) values were 3.94 and 5.74 kcal/mol for CpSK and EcSK, respectively. These results indicated that CpSK was a cold-adapted enzyme. However, contrary to typical kinetic data, CpSK had a lower $K_m$ for its substrate shikimate than most mesophilic SKs, and the $k_{cat}$ was not increased. This observation suggested that CpSK may have evolved to exhibit increased substrate affinity at low intracellular concentrations of shikimate in the cold environment. Sequence analysis and homology modeling also showed that some important salt bridges were lost in CpSK, and higher Arg residues around critical Arg 140 seemed to increase flexibility for catalysis. Taken together, these data demonstrate that CpSK exhibits characteristics of cold adaptation with unusual kinetic parameters, which may provide important insights into the cold adaptation of metabolic enzymes.

The Effect of Cold-adaptation on Stress Responses and Identification of a Cold Shock Gene, capA in Bradyrhizobium japonicum (Bradyrhizobium japonicum의 저온 전처리에 의한 환경스트레스 내성 증진에 대한 연구)

  • 유지철;노재상;오은택;소재성
    • Korean Journal of Microbiology
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    • v.38 no.1
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    • pp.45-49
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    • 2002
  • Bradyrhizobium japonicum is a soil bacterium with a unique ability to infect the roots of leguminous plants and establish a nitrogen-fixing symbiosis, which has been used as a microbial manure. In this study, we examined the stress response after pretreatment of cells with cold temperature. When pre-treated with cold temperature ($4^{\circ}C$) for 16 hr, B. japonicum increased the viability in subsequent stress-conditions such as alcohol, $H_2O_2$, heat, and dehydration. For cold adpatation, cultured B. japonicum was exposed to $4^{\circ}C$. Upon subsequent exposure to various conditions, the number of adapted cells pretreated by cold adaptation was 10-1000 fold higher than that of non-adaptated ones. It appeared de novo protein synthesis occurred during adaptation, because a protein synthesis inhibitor, chloramphenicol abolished the increased stress tolerance. By using a degenerate PCR primer set, a csp homolog was amplified from B. japonicum genome and sequenced. The deduced partial amino acid sequence of the putative Csp (Cold shock protein) shares a significant similarity with known Csp proteins of other bacteria.

Characterization of 5-Enolpyruvylshikimate-3-Phosphate Synthase from Colwellia psychrerythraea

  • Kim, Hak Jun
    • Microbiology and Biotechnology Letters
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    • v.50 no.2
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    • pp.235-239
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    • 2022
  • Psychrophiles have evolved to produce cold-adapted enzymes to enable survival in low-temperature environments. In this study, the cold adaptation of 5-enolpyruvylshikimate-3-phosphate synthase (CpsEPSPS) from Colwellia psychrerythraea, a model psychrophile, was analyzed. The optimum temperature for the activity of CpsEPSPS was found to be 25℃, with 35% activity remaining at 5℃. However, the unfolding temperature of CpsEPSPS was 54℃. This phenomenon is frequently observed in cold-active enzymes. As is the cases for most cold-active enzymes, the Km values of CpsEPSPS for its substrates were higher than those of Escherichia coli EPSPS. These results indicate that CpsEPSPS is cold-adapted, but not perfectly.

Cold Perception Responses according to Body Parts and Wearing Behaviors of College Students (대학생의 신체부위별 추위지각 반응과 착의 행동)

  • Zhang, Chong;Jun, Dae Geun;Jeong, Woon Seon
    • The Korean Journal of Community Living Science
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    • v.26 no.4
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    • pp.775-783
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    • 2015
  • This study investigates gender differences in cold perceptions and wearing behaviors for cold adaptation. A questionnaire composed of items on cold perceptions, intentions toward wearing additional clothing, and clothing for outdoor environments, among others, was used. Each item in the survey targeted 260 male (MS) and female (FS) college students evaluated using a five-point Likert-type scale. Data were statistically analyzed using the independent sample t-test and correlations. Main results can be summarized as follows: MS subjects showed lower dependence on the thermal insulation of clothing because they felt less cold and had the better ability to cope with cold. MS subjects had higher dependence on underwear during cold seasons, and FS subjects tended to wear heavier clothing to compensate for their cold feet with insufficient insulation. In addition, it was preferable to estimate thermal effects of actual wear by taking into account gender differences in the physique. The study is limited in that the room temperature and the actual amount of clothing were not measured, which offers an avenue for future research.

Cryobiological Perspectives on the Cold Adaptation of Polar Organisms (극지 생물의 저온적응 기작과 저온 생물학적 응용 연구)

  • Kang, Sung-Ho;Joo, Hyung-Min;Park, Seung-Il;Jung, Woong-Sic;Hong, Sung-Soo;Seo, Ki-Won;Jeon, Mi-Sa;Choi, Han-Gu;Kim, Hak-Jun
    • Ocean and Polar Research
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    • v.29 no.3
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    • pp.263-271
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    • 2007
  • The survival strategies of polar organisms at permanently or extremely cold temperatures and their application to cryobiology were reviewed here. In addition, ongoing studies on psychrophiles also were described. Psychrophiles are extremophiles that can grow and reproduce in cold temperatures, typically at -10 to $20^{\circ}C$. These organisms developed various mechanisms of adaptation to extremely cold environments. Polar organisms cope with these extreme physicochemical conditions using strategies such as avoidance, protection and partnership with other organisms. Understanding on the strategies adopted by polar organisms may provide insight on the physiological process that cells can go through during freezing. Cryopreservation may be able to take advantage of the findings described above. Currently, genomes of many cold-loving organisms have been sequenced and comparative genomics has revealed, at a molecular level, the characteristics of these organisms. The investigation of microorganisms on the polar glaciers may expand our understanding on the origin of life on Earth and other planets.

Effect of Clothing Habit on Climatic Adaptation by Female High School Students (여고생 착의습관이 기후적응에 미치는 영향)

  • 안필자
    • Journal of the Korean Society of Clothing and Textiles
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    • v.18 no.5
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    • pp.615-621
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    • 1994
  • This study was carried out to investigate the effect of clothing habit on physiological adaptation to the change of season. The survey of clothing weight in fall '||'&'||' winter for 2 years, the frequency of cold infection in winter and degree of fatigue was performed with 110 female high school students. The actual condition of clothing and the correlations between clothing weight and cold infection, and between the clothing weight and degree of fatigue were suveyed. The results are followed as; 1. The clothing insulation was nearly same to indoor standard clothing insulation in H hun wearing normal clothing, but was higher 2 clo in S hun clothed uniform. Especially in spite of similar enviromental condition the clothing weight, minimum '||'&'||' maximum and variation of clothing weight for 2 years were showed to be heavier in S hun than H hun. Also indoor thermal sensation felt by the subjects indicated "cold", and the difference between clothing insulation and standard clothing insulation showed increase gradually. 2. L group was indicated to be lower in cold infaction ratio than M '||'&'||' H group, and the correlation between clothing group and cold infection ratio was recognized to be significant (p<0.05). And H hun and L-H group showed to be lower in cold infection ratio than S hun, H-L group. 3. The coefficience between clothing weight and degree of fatigue was recognized to be significant (p<0.05).

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The Oxygen-Transport System of Polar Fish: The Evolution of Hemoglobin

  • Verde Cinzia;Prisco Guido di
    • Ocean and Polar Research
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    • v.25 no.4
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    • pp.617-623
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    • 2003
  • Organisms living in the Arctic and Antarctic regions are exposed to strong constraints, of which temperature is a driving factor. Evolution has led to special adaptations, some with important implications at the biochemical, physiological, and molecular levels. The northern and southern polar oceans have very different characteristics. Tectonic and oceanographic events have played a key role in delimiting the two polar ecosystems and influencing evolution. Antarctica has been isolated and cold longer than the Arctic; its ice sheet developed at least 10 million years earlier. As an intermediate system, the Arctic is a connection between the more extreme, simpler Antarctic system and the very complex temperate and tropical systems. By studying the molecular bases of cold adaptation in polar fish, and taking advantage of the information available on hemoglobin structure and function, we analysed the evolutionary history of the ${\alpha}\;and\;{\beta}globins$ of Antarctic and Arctic hemoglobin using the molecular clock hypothesis as a basis for reconstructing the phylogenetic relationships among species.

Improved Viability and Proteome Analysis of Lactobacillus fermentum KLB12 upon Heat Stress (Lactobacillus fermentum KLB12의 열 전처리에 따른 열 스트레스 내성 증진 및 프로테옴 변화)

  • 김주현;박미영;김승철;윤현식;소재성
    • KSBB Journal
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    • v.18 no.4
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    • pp.294-300
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    • 2003
  • In the previous study, we have isolated several vaginal lactobacilli from Korean woman and selected one of them (KLB12) for further study, which was indentified as Lactobacillus fermentum by sequence analysis of 16S rRNA gene. Formulated L. fermentum KLB12 can be used for ecological treatment of bacterial vaginosis. For pharmaceutical formulation, the spray-drying process is required where stress such as high temperature is routinely applied. In this study, we found that heat stress at 60$^{\circ}C$ for 20∼30min reduced the viable cell population of KLB12 by 10$\sub$6/~10$\sub$9/. However, adaptation of KLB12 cells at 52$^{\circ}C$ made them more thermotolerant upon exposure to 60$^{\circ}C$. The level of thermal protection in RSM (reconstituted skim milk) by adaptation in acid (pH 5), cold (4$^{\circ}C$), ethanol (3%), NaCI (0.3M) was also examined. Although not as efficient as the homologous stress, adaptations in both cold and NaCI gave considerable cross protection against heat stress. When chloramphenicol was added during heat adaptation, adaptation effect was abolished. This suggests that de novo protein synthesis is necessary during the adaptation process. Important changes in proteome during heat adaptation was examined with two-dimensional gel electrophoresis.