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南极冰藻是南大洋碳流和能量流的重要组成部分,在该区域的生态系统中发挥着极其重要的作用.低温、低光照和高盐度对类囊体膜光系统的伤害必将影响冰藻对光能的吸收、传递和转换,从而影响冰藻的正常生长繁殖.事实上,冰藻为了能够在这寒冷骤变的环境中生存、繁衍,类囊体膜光系统在生理、代谢和遗传上进行了复杂的适应性改变,冰藻在低光照条件下保持很高的光合效率.因此研究南极冰藻类囊体膜光系统具有重要的理论意义.综述了南极冰藻类囊体膜光系统的研究进展,以期为进一步了解南极冰藻光系统作用机理提供依据. 相似文献
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Screening and molecular classification of low-temperature protease from Antarctic microorganism and its characterization 
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下载免费PDF全文 <正> 107 strains producing protease were screened from 260 strains of Ant-arctic psychrophilic bacteria,among which proteolytic activity of five strains wasmore than 45 U ml~(-1).The 16S rRNA gene sequences homology and phylogenet-ic analysis of five Antarctic psychrophilic bacteria showed that NJ276、NJ5-9、NJ16-70、NJ345 belonged to the described genus Pseudoalteromonas and NJ341belonged to the genus Colwellia.The growth and the protease characteristic offour Antarctic psychrophilic bacteria had been studied,and the result showedthat the optimal temperature for growth and protease-producing of four strainswas about 10℃.Their growth and protease-producing were still high during in-cubating 2-5 days.The maximum proteolytic activity occurred at pH 9 for fourAntarctic psychrophilic bacteria.The optimal temperature of protease action ofboth strains NJ276 and NJ5-9 was about 50℃,however,the optimal temperatureof protease action of both strains NJ341 and NJ345 was about 40℃,and theirproteolytic activity under 0℃ exhibited nearly 30% of the maximum activity,but their thermal stabilities were weaker.These results indicated that proteasesfrom NJ341 and NJ345 were low-temperature proteases. 相似文献
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羟化酶是细菌降解烷烃的关键酶,本文以南极低温降解菌Shewanella sp.NJ49为研究对象,通过硫酸铵沉淀、超滤浓缩及葡聚糖凝胶Sephadex G-75柱层析方法,分离纯化NJ49的羟化酶,获得了单一羟化酶组分,研究了温度、p H、表面活性剂和盐度等环境因素对NJ49羟化酶酶活活性影响。结果表明,羟化酶组分由α、β、γ三个亚基组成,分子质量分别为56,45和36 k D。NJ49最适产酶条件为:温度15℃、p H7.2、盐度55;不同类型表面活性剂对酶的活性影响效应不一,两性离子表面活性剂、阳离子表面活性剂、非离子表面活性剂对酶活没有作用,阴离子表面活性剂+非离子表面活性剂混和剂和阳离子表面活性剂+非离子表面活性剂混和剂能提高羟化酶的活性。 相似文献
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The ability of cell to modulate the fluidity of plasma membrane was crucial to the survival of microorganism at low temperature.Plasma membrane proteins,fatty acids and carotenoids profiles of Antarctic psychrophilc yeast Rhodotorula sp.NJ298 were investigated at-3 ℃,0 ℃ and 8 ℃.The results showed that plasma membrane protein content was greater at-3 ℃ than that at 8 ℃,and a unique membrane polypeptide composition with an apparent molecular mass of 94.7 kDa was newly synthesized with SDS-PAGE analysis;GC analysis showed that the main changes of fatty acids were the percentage of unsaturated fatty acids(C18:1 and C18:2) and shorter chain saturated fatty acid(C10:0) increased along with the decrease of the culture temperature from 8 ℃ to-3 ℃;HPLC analysis indicated that astaxanthin was the major functional carotenoids of the plasma membrane,percentage of which increased from 54.6±1.5% at 8 ℃ to 81.9±2.1% at-3 ℃.However the fluidity of plasma membrane which was determined by measuring fluorescence anisotropy was similar at-3 ℃,0 ℃ and 8 ℃.Hence these changes in plasma membrane's characteristics were involved in the cellular cold-adaptation by which NJ298 could maintain normal plasma membrane fluidity at near-freezing temperature. 相似文献
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107 strains producing protease were screened from 260 strains of Antarctic psychrophilic bacteria, among which proteolytic activity of five strains was more than 45 U ml^-1. The 16S rRNA gcne sequences homology and phylogcnetic analysis of five Antarctic psychrophillc bacteria showed that NJ276, NJS-9, NJ16-70,NJ345 belonged tO the described genus Pseudoalteromonas and NJ341 belonged to the genus Colwellia. The growth and the protease characteristic of four Antarctic psychrophilic bacteria had been studied, and the result showed that the 6ptimal temperature for growth and protease-produeing of four strains was about 10℃. Their growth and protease-produeing were still high during incubatlng 2-5 days. The maximum proteolytic activity occurred at pH 9 for four Antarctic psychrophilic bacteria. The optimal temperature of protease action of both strains NJ276 and NJ5-9 was about 50℃, however, the optimal temperature of protease aetlon of both strains NJ341 and NJ345 was about 40 ℃, and their proteolytic activity under 0℃ exhibited nearly 30% of the maximum activity, but their thermal stabilities were weaker. These results indicated that proteases from NJ341 and NJ345 were low-temperature proteases. 相似文献
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The changes of plasmalemma permeability and some primary inorganic ions of Antarctic ice microalgae （ Chlamydomonas sp. ICE-L） in the low-temperature stress were examined. The plasmalemma of 1CE-L could maintain the stability at the freezing condition of -6 ℃. That signifies that it could maintain the proper function of plasmalemma and stability of the intracellular environment during sea ice formation. The function of inorganic ions on low-temperature adaptation of ICE-L was investigated by using the X-ray microanalysis method. Low temperature （0 - -6 ℃ ） induces Ca^2 ＋ concentration increment of cytoplasm, but after 24 h the content decrease quickly to normal value. As a matter of fact, Ca^2 ＋ plays an important role as the second messenger in the low temperature adaptation of ICE-L. In addition, low temperature also influences on the other primary inorganic ions transfer and the cell maintains activity by keeping ratio balance among different ions. Above all, it is necessary for Antarctic ice microalgae to survive and breed by maintaining the stability of K^ ＋ content and the balance of Na^ ＋/Cl^ -. 相似文献
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温度对南极衣藻ICE-L(Chlamydomonas sp. ICE-L)谷胱甘肽含量及其相关酶活性的影响 总被引：6，自引：2，他引：6
采用分光光度法研究了在不同温度下(包括最适温度、低于或高于最适温度)南极衣藻ICE-L(Chlamydomonassp.ICE-L)谷胱甘肽(GSH)含量、蛋白含量、谷胱甘肽过氧化物酶(GPx)、谷胱甘肽还原酶(GR)和谷胱甘肽硫转移酶(GST)活性,同时分析了已适应高温(16℃)的衣藻重新适应低温(8℃)时这些指标的变化,以期阐明谷胱甘肽系统与南极冰藻低温适应性的关系。结果表明,当温度低于对照组(最适温度8℃)时,蛋白含量降低,而GSH含量、GPx、GST和GR活性上升,已适应高温的衣藻重新适应低温时也出现类似的结果。但当温度高于最适温度时,GSH含量、GST和GPx活性下降,而蛋白含量和GR活力有上升的趋势,GR活力增长幅度比低于最适温度时的变化小。由此可见谷胱甘肽系统在南极衣藻低温适应过程中,GSH、GPx、GR、GST与低温适应呈正相关,同时除GR外其他因子与南极衣藻高温适应呈负相关,GSH及其相关酶在南极冰藻低温适应中具有重要作用。 相似文献
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对从南极地区采集的嗜冷菌NJ41和NJ289的对萘降解特性进行初步研究.确定其最适的培养条件,并在最适培养条件下测定菌株的生长曲线和萘降解曲线.经分子鉴定,NJ41属于动球菌属(Planococcus sp.)、NJ289属于假交替单胞菌属(Pseudoalteromonas sp.).实验表明:这2株嗜冷菌均可在以萘等芳香烃为唯一碳源的无机盐培养基中生长,并能够在低温环境(0～10℃)中高效地降解芳香烃;10℃,120 r/min,10 d时,NJ41对于萘的降解能力最高达48.8%,NJ289可达43.5%;温度对降解能力有很大的影响,NJ41和NJ289均在10℃时,具有最高的降解能力,温度升高降解能力下降,NJ41在超过25℃时则基本不具有降解能力,而NJ289在超过20℃时就不具备降解能力. 相似文献
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假交替单胞菌属归属于交替假单胞菌科。交替假单胞菌N289菌株分离自南极海冰,我们通过二代测序技术获得了其全基因组序列,组装后获得2条染色体和1条质粒,大小分别是3.2M、636kb和1.8kb。全基因组共包含3,589个ORF,GC含量为40.83%。基因功能分析表明,该菌酶活性高,具有很强的环境适应性。这项研究有助于了解生物多样性、该菌株的进化地位和微生物相互作用关系。 相似文献