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1.
适冷微生物及其适冷机制研究进展   总被引:7,自引:0,他引:7       下载免费PDF全文
地球上许多生境为永久低温或季节性低温环境,适冷微生物在自然界中广泛存在。适冷微生物在环境净化、饲料、食品、奶制品、化妆品、皮革加工、洗涤等行业中具有广泛的应用前景。对适冷微生物的多样性、适冷的分子基础和适冷代谢机制进行了综述。  相似文献   

2.
食品中低温微生物的适冷机制研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
低温贮藏是延长食品货架期、维持食品鲜度和质量安全的重要方法,然而仍有部分微生物能适应低温环境,使食品发生腐败变质。主要从细胞膜、适冷酶、冷休克蛋白、冷适应蛋白、代谢水平及低温防护剂等角度阐述国内外食品中低温微生物适冷机制的研究进展,为低温微生物在食品领域的应用与防护提供参考。  相似文献   

3.
昆虫冷驯化机制研究进展   总被引:1,自引:1,他引:0  
孔璐  郭建英  周忠实  万方浩 《昆虫知识》2012,49(6):1664-1669
昆虫耐寒性强弱决定其种群的发生、扩散和分布,因此低温胁迫下昆虫的抗寒对策成为近期研究的热点领域。冷驯化作为一种非常有效的耐寒策略,可显著增强昆虫的耐寒性。本文论述了冷驯化的2种基本形式:快速冷驯化和长时冷驯化,明确了二者在提升昆虫耐寒性中的作用;并从宏观到微观的角度概述了冷驯化的作用机制,如组织和细胞水平的特异性,低分子量抗冻保护剂的产生,热休克蛋白的表达及功能,以及阻止细胞程序性死亡的潜在机理等;讨论了不同研究方法所引起的结果差异性,并强调了冷驯化作用机制的整体效益和综合效益。最后通过分析2种冷驯化形式的联系与区别,以期较为全面地阐明昆虫冷驯化的潜在机制。  相似文献   

4.
低温微生物及其酶类的研究概况   总被引:8,自引:0,他引:8  
广泛分布在地球寒冷生境 ,如南北两极、高山、深海以及冰川中的低温微生物 ,不但为研究低温生态系统、生命起源与进化以及生物适冷机制提供了丰富的材料 ,同时在生物工程方面也具有潜在的巨大开发价值。国内外越来越多的科研人员对低温微生物及其产物的研究表现出了浓厚的兴趣。关于细胞膜和低温酶的研究 ,是目前微生物适冷机制研究中的 2个热点。就低温微生物的研究现状和适冷机制以及低温酶类的研究进行了综述。  相似文献   

5.
昆虫抗冻耐寒能力因其理论意义和实践价值成为当前生物学和生态学的重要研究内容。尤其昆虫抗冻耐寒能力的测定与分析是昆虫低温生物学的热点问题。本文从昆虫生态,及生理生化层面阐述了昆虫抗冻策略和耐寒机制类型。进一步介绍了昆虫抗冻耐寒能力的测定与分析方法:一方面,以昆虫种群为对象,分析低温对种群存活的胁迫作用,如低温实验中种群的存活率,致死中温度或致死中时间,冷伤害上限温度,冷害低温总和,以及低温冷伤害的死亡速率等。另一方面,以昆虫个体为对象,测定个体为适应低温环境而采取响应机制,如昆虫个体过冷却点、含水量、能量物质、抗冻小分子物质和抗冻蛋白含量等。在未来,从微观上看随着低温生物学拓展到基因组、转录组、蛋白质组及代谢组层次的研究,从宏观上看随着越冬代昆虫种群数量动态及其迁飞转移行为规律与栖息地微环境气候和区域性景观格局特征等的关系研究,有利于更全面地和深入地了解昆虫类群的抗冻策略或耐寒机制,从而为更系统地建立昆虫抗冻耐寒能力的测定与分析方法体系提供可靠指标。  相似文献   

6.
[目的]微生物在适应外界环境急剧降温的条件下都会发生应激反应,产生一系列蛋白质被称为冷休克蛋白.冷休克蛋白对乳酸菌适应低温环境和增强抗冻能力方面发挥着重要作用.本文目的是为了研究乳酸乳球菌中冷休克蛋白CspC、CspD的作用.[方法]将冷休克蛋白CspC、CspD基因分别重组到质粒pNZ8148,转化乳酸乳球菌NZ9000后,加入Nisin诱导,对表达产物进行SDS-PAGE电泳分析,比较重组菌与空白菌在30℃条件下菌体生长差异及反复冻融活菌数的差异.[结果]得出CspC、CspD的相对分子量分别为7.0、6.2 kDa.[结论]CspC使菌体更加迅速的恢复了生长;冷休克蛋白CspD增强了菌体的抗冻存活率(增加了30~40倍).  相似文献   

7.
生物圈的80%是由低温环境构成,大约90%的海水平均温度为5℃或者更低,这里孕育着极为丰富的微生物。根据微生物对环境温度的耐受性和其生长温度上限/下限的不同,将微生物分为嗜冷微生物和适冷微生物两大类。由这些微生物产生的适冷酶在低温下具有较高的催化效率和特异性,因而在生物技术领域具有巨大的应用潜力和开发价值。总结了近5年适冷酶新酶的筛选、发现及适冷酶稳定性的改造和低温表达系统等方面的最新研究进展,并对该领域的研究方向进行了展望。  相似文献   

8.
嗜冷酶及其工业应用   总被引:12,自引:0,他引:12  
史贤俊  林影 《生命的化学》2001,21(3):248-249
生物圈中超过 80 %的地方温度低于5℃ ,在生态学上低温环境的影响范围更广。生活在这些低温环境中的嗜冷菌对低温有特殊的适应性。相对于嗜温菌而言 ,嗜冷微生物在低温条件下调节其膜流动性和膜通透性的能力更强 ,含有更多的不饱和脂肪酸和短链脂肪酸 ,还可通过合成冷激蛋白来响应冷激作用。嗜冷菌也可通过基因调控和自身的抗生素作用来适应低温。近来有研究报道 ,南北极严寒地区的海洋鱼类依靠血液中的抗冻蛋白来适应低温。生物体内的大多数生化反应都是由酶催化而成的 ,所以考虑嗜冷微生物的适应机制时首先应研究嗜冷酶的适冷机制。1 .嗜…  相似文献   

9.
低温细菌与古菌的生物多样性及其冷适应机制   总被引:1,自引:0,他引:1  
低温细菌与古菌广泛分布于地球的低温环境,包括南极、北极及高山地带的冻土、低温土壤和荒漠、冰川、湖泊、海冰,以及深海、冰洞和大气平流层等.栖息在这些低温环境中的细菌与古菌具有丰富的多样性,主要为α,p和γ-Proteobacteria分支、CFB类群分支和革兰氏阳性细菌分支等.由于低温环境中的微生物流动性低,因而是研究微生物地理学理想的生态系统,有助于理解地球微生物的多样性、分布规律乃至形成机制.由于长期生活在冰冻环境中,低温细菌与古菌形成了多种适应低温环境的生理机制,如它们通过细胞膜脂类的组成来调节膜的流动性以维持正常的细胞生理功能;利用相容性溶质、抗冻蛋白、冰核蛋白及抗冰核形成蛋白等实现低温保护作用;产生冷激蛋白、冷适应蛋白和DEAD-box RNA解旋酶保持低温下RNA的正确折叠、蛋白质翻译等重要的生命活动;另外还产生低温酶,提高能量产生和储存效率等以适应低温环境.随着DNA序列分析技术的飞速发展,各类组学方法也用于揭示微生物全局性的冷适应机制.  相似文献   

10.
冷血脊椎动物冷适应研究   总被引:4,自引:0,他引:4  
环境温度是制约冷血脊椎动物分布、生存、繁殖、迁徙等活动最重要的生态因子之一.冷血脊椎动物在多种多样栖息环境中形成多种耐寒策略.本文重点从冷血脊椎动物冷适应行为生态、生理、冷冻诱导基因表达与抗冻物质获得、低温与性别决定等方面对国内外研究进展进行综述,以探讨低温生物学在冷血脊椎动物的发展趋势.  相似文献   

11.
嗜冷菌及耐冷菌是冷适应酶及生物活性物质的重要资源。本研究从内陆土壤筛得33株冷适应细菌,包括6株革兰氏阳性菌与27株革兰氏阴性菌。通过细胞膜脂肪酸分析表明,革兰氏阳性菌的膜脂肪酸主要为分支脂肪酸,推测分支结构是阳性菌膜脂的主要适冷机制。革兰氏阴性菌呈现了不饱和、分支、短链等多样的膜脂适冷调节方式。根据脂肪酸组分的多样性,选择并鉴定了17株嗜冷及耐冷菌分布在11个属中,细胞膜脂肪酸组成的变化规律与细菌16SrRNA的进化分布高度一致。研究还表明同为不饱和脂肪酸为主的革兰氏阴性菌呈现了不同的适冷机理。相关研究不仅阐述了冷适应细菌的细胞膜脂肪酸的适应机制,而且为相关适冷酶源的开发利用提供了宝贵的资源。  相似文献   

12.
Cold-adapted archaea   总被引:1,自引:0,他引:1  
Many archaea are extremophiles. They thrive at high temperatures, at high pressure and in concentrated acidic environments. Nevertheless, the largest proportion and greatest diversity of archaea exist in cold environments. Most of the Earth's biosphere is cold, and archaea represent a significant fraction of the biomass. Although psychrophilic archaea have long been the neglected majority, the study of these microorganisms is beginning to come of age. This review casts a spotlight on the ecology, adaptation biology and unique science that is being realized from studies on cold-adapted archaea.  相似文献   

13.
The effect of different growth temperatures on the production of 11 extracellular enzymes was studied in nine cold-adapted bacterial strains isolated from various cold environments. Ten of these enzymes displayed temperature-dependent production. Five different temperature-related production patterns were identified, which depended on neither the type of strain, nor the nature of the enzyme.  相似文献   

14.
To determine the role of the nutritional state in nonshivering thermogenesis during cold adaptation, cold adaptability was compared between cold-adapted (5 degrees C for 4-5 weeks) rats fed ad libitum and cold-adapted rats pair fed with warm controls having the same food intake. Cold-adapted pair-fed rats suffered a significant loss in body weight during cold exposure. However, brown adipose tissue (BAT) in both cold-adapted ad libitum fed and cold-adapted pair-fed rats was enlarged to the same extent as compared with that in control rats. Fat-free dry matter in BAT also increased in cold-adapted ad libitum fed and cold-adapted pair-fed rats to the same extent. Cold tolerance as assessed by the change in the colonic temperature at -5 degrees C was improved relative to control rats and was the same for cold-adapted ad libitum fed and cold-adapted pair-fed rats. Nonshivering thermogenesis as estimated by the noradrenaline-induced increase in oxygen consumption was significantly greater in the cold-exposed rats and there was no significant difference between cold-adapted ad libitum fed and cold-adapted pair-fed rats. These results suggest that an improved cold tolerance by means of nonshivering thermogenesis in brown adipose tissue is closely related to the low temperature itself but not the increased food intake which occurred in the cold.  相似文献   

15.
Low-temperature extremophiles and their applications   总被引:32,自引:0,他引:32  
Psychrophilic (cold-adapted) organisms and their products have potential applications in a broad range of industrial, agricultural and medical processes. In order for growth to occur in low-temperature environments, all cellular components must adapt to the cold. This fact, in combination with the diversity of Archaea, Bacteria and Eucarya isolated from cold environments, highlights the breadth and type of biological products and processes that might be exploited for biotechnology. Relative to this undisputed potential, psychrophiles and their products are under-utilised in biotechnology; however, recent advances, particularly with cold-active enzymes, herald rapid growth for this burgeoning field.  相似文献   

16.
Despite the presence and abundance of archaea in low-temperature environments, little information is available regarding their physiological and biochemical properties. In order to investigate the adaptation of archaeal proteins to low temperatures, we purified and characterized the elongation factor 2 (EF-2) protein from the Antarctic methanogen Methanococcoides burtonii, which was expressed in Escherichia coli, and compared it to the recombinant EF-2 protein from a phylogenetically related thermophile, Methanosarcina thermophila. Using differential scanning calorimetry to assess protein stability and enzyme assays for the intrinsic GTPase activity, we identified biochemical and biophysical properties that are characteristic of the cold-adapted protein. This includes a higher activity at low temperatures caused by a decrease of the activation energy necessary for GTP hydrolysis and a decreased activation energy for the irreversible denaturation of the protein, which indicates a less thermostable structure. Comparison of the in vitro properties of the proteins with the temperature-dependent characteristics of growth of the organisms indicates that additional cytoplasmic factors are likely to be important for the complete thermal adaptation of the proteins in vivo. This is the first study to address thermal adaptation of proteins from a free-living, cold-adapted archaeon, and our results indicate that the ability of the Antarctic methanogen to adapt to the cold is likely to involve protein structural changes.  相似文献   

17.
The genus Shewanella is one of the typical deep-sea bacterial genera. Two isolated deep-sea Shewanella species, Shewanella benthica and Shewanella violacea, were found to be able to grow better under high hydrostatic pressure conditions than at atmospheric pressure. These species are not only piezophilic (barophilic), but also psychrophilic. Many psychrophilic and psychrotolerant Shewanella species have been isolated and characterized from cold environments, such as seawater in Antarctica or the North Sea. Some of these cold-adapted Shewanella were shown to be piezotolerant, meaning that growth occurs in a high-pressure habitat. In this review, we propose that two major sub-genus branches of the genus Shewanella should be recognized taxonomically, one group characterized as high-pressure cold-adapted species that produce substantial amounts of eicosapentaenoic acid, and the other group characterized as mesophilic pressure-sensitive species.  相似文献   

18.
Growth of prokaryotes at reduced temperature results in the formation of a cold-adapted ribosome through association with de novo synthesized polypeptides. In vitro and in vivo phosphorylation studies combined with affinity purification and mass spectrometry identified that the phosphorylation status of translation elongation factor EF-Tu was altered in response to cold stress in the photosynthetic, Gram-negative cyanobacterium Anabaena sp. strain PCC 7120. In response to a temperature downshift from 30 to 20 degrees C, EF-Tu was rapidly and transiently hyperphosphorylated during the acclimation phase followed by a reduction in phosphorylation below background levels in response to prolonged exposure. EF-Tu was identified as a phosphothreonine protein. Unexpectedly, ribosomal protein S2 was also observed to be a phosphoprotein continuously phosphorylated during cold stress. The phosphorylation status of EF-Tu has previously been associated with translational regulation in other systems, with a reduction in translation elongation occurring in response to phosphorylation. These results provide evidence for a novel mechanism by which translation is initially downregulated in response to cold stress in Anabaena.  相似文献   

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