In order to thoroughly investigate the diversity of glacier microorganisms, four DNA extraction methods with differem lysis pat- terns were tested and two screened methods （the Bosshard-Bano method and the Zhou method） were optimized for the most ef- fective form of the filter membrane （cut vs. uncut）, the DNA extraction method, and the precipitation method. The two optimized methods were then compared with the commercial Mo-Bio DNA extraction kit, and the results showed that the kit was generally suitable for extraction of microorganism DNA fi＇om glacier surface snow. Procedurally, it was found that a modified Boss- hard-Bano method （i.e., cutting the filter membrane into pieces, using a specific lysis pattern [lysozyme （5 mg/mL）-protease K （ 1 mg/mL）-CTAB （ 1%）-SDS （ 1%）], performing the extraction only once by chloroform-isoamyl alcohol （24： 1）, and conducting DNA precipitation by pure ethanol） was also an effective and less expensive method for extraction of microorganism DNA from glacier surface snow.
PeiYing YanShuGui HouTuo ChenShuHong ZhangWeiJun Sun
In this paper, recent glacier and lake changes research on the Tibetan Plateau was reviewed. Emphasis was placed on a discussion of the relationship between glacier shrinkage and lake change. In the context of global climate change, the glaciers of the Tibetan Plateau have general y retreated, while the lakes have general y expanded. First, the research on glacial terminal retreat, glacial area and volume variations across the Tibetan Plateau over the last few decades are reviewed and analyzed; the temporal-spatial change characteristics of the glaciers are discussed. Secondly, the lake area, volume and water level changes are reviewed and analyzed;the temporal-spatial change characteristics of the glaciers are discussed. The results indicate that the retreat speed in the outer edge of the Tibean Plateau was overal faster than that in the inland area. The areas and water levels of the lakes that are fed by glacial water increased. Final y, the limitations of the present studies and future work are discussed.
Over the past 15 years there has been much effort invested in microorganisms of glacial snow and ice on the Tibetan Plateau.These studies include:phenotypic characteristics of recovered isolates;factors(dust,temperature,altitude)influencing microbial abundance,diversity and community in one glacier;distribution of bacterial number,diversity,community along ice core depth;similarities and differences of regionally distributed ice core isolates;seasonal variation of bacterial abundance and diversity.The following need further study.Better methods for more information about the diversity,survival mechanism of glacial microorganism;more research about archaea and fungi;microbial resources;relation of glacial microorganisms with biogeochemical cycle and mass balance;research on altitude distribution.
