LEXEN: Biology and Ecology of South Pole Snow Microbes

[9713990]泰勒计划摘要南极洲大陆的内部冰原一直被认为没有本土生物。虽然植物、原生动物和细菌存在于大陆的边缘，但低温、长时间的黑暗和缺乏液态水的结合，使大陆内部对生命极为不利。然而，最近对南极雪的研究表明，其中存在含有DNA和光合色素的微生物。1997年1月在南极站收集了雪样，并立即空运到麦克默多基地的克雷实验室。用荧光显微镜检查雪融水，发现存在棒状颗粒，大小约为1 X 2.5 um，浓度为130 （sd=64）个细胞/ ml。这些颗粒在蓝色激发光下发出橙色荧光，在绿色激发光下发出红橙色荧光，表明存在藻胆蛋白和叶绿素。这些荧光特征结合颗粒的形状表明它们是蓝藻。随后使用荧光DNA染色和扫描电子显微镜进行分析，证实了含有微生物的DNA的存在，其形状与用荧光显微镜观察到的自荧光颗粒相同。进一步的研究将证实这些微生物是否是南极内陆的土著，并调查它们的生物学和生态学。能够在南极洲内陆生存的生物的发现将使我们对生命的适应性有新的认识。它们的生物分子和代谢一定是独特的，在分子工程研究中有很大的价值。

9713990 Taylor PROJECT SUMMARY The interior ice sheets of the continent of Antarctica have always been assumed to be devoid of indigenous organisms. While plants, protozoa, and bacteria are present at the fringes of the continent, the combination of low temperatures, long periods of darkness, and the absence of liquid water make the interior extremely hostile to life. However, recent examination of snow from the South Pole indicates the presence of microbes which contain DNA and photosynthetic pigments. Snow samples were collected at South Pole station in January 1997 and flown immediately to the Crary Lab at McMurdo Base. Examination of snowmelt using epifluorescence microscopy showed the presence of rod shaped particles approximately 1 X 2.5 um in size and a concentration of 130 (sd=64) cells per ml. The particles fluoresced orange under blue excitation light and reddish-orange under green excitation, indicating the presence of phycobiliproteins and chlorophyll. These fluorescence signatures combined with the particles' shape suggests that they are cyanobacteria. Subsequent analysis using fluorescent DNA stains and scanning electron microscopy confirmed the presence of DNA containing microbes identical in shape to the autofluorescing particles seen with epifluorescent microscopy. Further research will confirm whether these microbes are indigenous to the Antarctic interior and investigate their biology and ecology. The discovery of organisms capable of survival in interior Antarctica would provide us with new insight into the adaptability of life. Their biomolecules and metabolism must be unique and could have great value for molecular engineering research.