LEXEN: Biology and Ecology of South Pole Snow Microbes

9713990泰勒项目摘要南极洲大陆内部的冰盖一直被认为没有土著生物。虽然植物、原生动物和细菌存在于大陆的边缘，但低温、长期黑暗和缺乏液态水的组合使大陆内部对生命极为敌视。然而，最近对南极降雪的检查表明，存在含有DNA和光合色素的微生物。1997年1月在南极站采集了雪样，并立即将其空运到麦克默多基地的克雷里实验室。在荧光显微镜下观察到融雪体的直径约为1×2.5微米的棒状颗粒，浓度为130个/ml(SD=)，在蓝色激发光下发出橙色荧光，在绿色激发下发出橙红色荧光，表明藻胆蛋白和叶绿素的存在。这些荧光信号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的分析证实，DNA中含有形状与荧光显微镜所见的自发荧光颗粒相同的微生物。进一步的研究将确认这些微生物是否是南极内陆的本土微生物，并调查它们的生物学和生态学。能够在南极洲内部生存的生物的发现将为我们提供对生命适应性的新见解。它们的生物分子和代谢必须是独一无二的，在分子工程研究中可能具有巨大的价值。

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.