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The arid soils of the Antarctic Dry Valleys constitute some of the oldest, coldest, driest and most oligotrophic soils on Earth. Early studies suggested that the Dry Valley soils contained, at best, very low levels of viable microbiota. However, recent applications of molecular methods have revealed a dramatically contrasting picture - a very wide diversity(More)
An organism growing at 88 degrees C that closely resembles Desulfurococcus mucosus produced a single extracellular proteinase. We have purified this enzyme and carried out a preliminary characterization. The proteinase, which is a serine-type enzyme, had a molecular mass of 52,000 Da by SDS/polyacrylamide-gel electrophoresis, but only 10,000-13,000 Da by(More)
Nitrilase activity was induced in the thermophilic bacterium Bacillus pallidus strain Dac521 by growth on benzonitrile-supplemented minimal medium. The enzyme had a subunit relative molecular mass of 41 kDa but was purified as a complex with a putative GroEL protein (total M r, 600 kDa). The enzyme catalyzed the hydrolysis of aliphatic, aromatic, and(More)
Hypolithic communities represent important reservoirs of microbial life in hyper-arid deserts. A number of studies on the diversity and ecology of these communities from different geographic areas have been reported in the past decade, but the spatial distribution of the different components of these communities is still not understood. Moss- and(More)
A haloalkaliphilic archaeon (strain DS12T) isolated from Lake Zabuye, the Tibetan Plateau, China, was characterized to elucidate its taxonomy. The strain was aerobic, chemo-organotrophic, and grew optimally at 40 degrees C, pH 9.5-10.0 and 3.4 M NaCl. Cells of strain DS12T were non-motile cocci and stained Gram-variable. The major polar lipids of strain(More)
Strain EJ-46T, a novel pleomorphic, aerobic, extremely halophilic member of the Archaea was isolated from sediment of the saline Lake Ejinor, in Inner Mongolia, China. This organism was neutrophilic and required at least 15 % (2.5 M) NaCl for growth. MgCl2 was not required. The isolate was able to grow at pH 6.0-9.0. Optimum growth occurred in media(More)
The Miers Valley within the McMurdo Dry Valleys of Antarctica supports abundant quartz and marble substrates for hypolithons—microbial colonists on the underside of these translucent rocks. Three physically distinct hypolithic community types have been identified: cyanobacteria dominated (Type I), fungus dominated (Type II) or moss dominated (Type III). The(More)
Three Gram-positive, moderately halophilic, spore-forming rods, designated XH-63T, XH-62 and EJ-15, were isolated from two salt lakes located near Xilin Hot and Ejinor, in Inner Mongolia, China. The strains were strictly aerobic and motile, with spherical, terminal and deforming endospores. They grew at pH 5.0-9.0 (optimal growth at pH 7.5), between 4 and(More)
We used cultivation-independent methods to investigate the prokaryotic biogeography of the water column in six salt lakes in Inner Mongolia, China, and a salt lake in Argentina. These lakes had different salt compositions and pH values and were at variable geographic distances, on both local and intercontinental scales, which allowed us to explore the(More)
Much of the Earth's surface, both marine and terrestrial, is either periodically or permanently cold. Although habitats that are largely or continuously frozen are generally considered to be inhospitable to life, psychrophilic organisms have managed to survive in these environments. This is attributed to their innate adaptive capacity to cope with cold and(More)