Genome of a thermophilic bacterium Geobacillus sp. TFV3 from Deception Island, Antarctica

Thermophilic microorganisms have always been an important part of the ecosystem,particularly in a hot environment,as they play a key role in nutrient recycling at high temperatures where most microorganisms cannot cope.While most of the thermophiles are archaea,thermophiles can also be found among some species of bacteria.These bacteria are very useful in the fundamental study of heat adaptation,and they are also important as potential sources of thermostable enzymes and metabolites.Recently,we have isolated a Gram-positive thermophilic bacterium,Geobacillus sp.TFV3 from a volcanic soil sample from Deception Island,Antarctica.This project was undertaken to analyze the genes of this thermophilic Antarctic bacterium and to determine the presence of thermal-stress adaptation proteins in its genome.The genome of Geobacillus sp.TFV3 was first purified,sequenced,assembled,and annotated.The complete genome was found to harbor genes encoding for useful thermal-stress adaptation proteins.The majority of these proteins were categorized under the family of molecular chaperone and heat shock protein.This genomic information could eventually provide insights on how the bacterium adapts itself towards high growth temperatures.

Alicyclobacillus sp. strain CC2, a thermo-acidophilic bacterium isolated from Deception Island(Antarctica) containing a thermostable superoxide dismutase enzyme

A gram-positive, rod-shaped, aerobic, thermo-acidophilic bacterium CC2 （optimal temperature 55℃ and pH 4.0）, belonging to the genus Alicyclobacillus was isolated from geothermal soil collected from ＂Cerro Caliente＂, Deception Island, Antarctica. Owing to the harsh environmental conditions found in this territory, microorganisms are exposed to conditions that trigger the generation of reactive oxygen species （ROS）. They must have an effective antioxidant defense system to deal with this oxidative stress. We focused on one of the most important enzymes： superoxide dismutase, which was partially purified and characterized. This study presents the first report of a thermo-acidophilic bacterium isolated from Deception lsland with a thermostable superoxide dismutase （SOD）.

Microbes in the area of the South Shetland Islands

Investigations were made on the microbes in the air, bottom sediments, surface seawater in the sea area of the South Shetland Islands during December, 1986～March, 1987.The results obtained show that: from the air over the South Shetland Islands and the Maxwell Bay,the detection rate of terrigenous microbes was more than 90% and their amount was generally a few CFU/m3; the detection rate of marine microbes was more than 50% and their amount only 1 CFU/m3. The amounts of air-borne microbes over the surveyed area were the witness to their diurnal variations. They were influenced to some extent by nearby islands. Air temperature and relative humidity,etc. were factors affecting their quantitative variations.The bacterial amount of the outshore surface sea water in the Great Wall Bay, Antarctica was about n×10 CUF/cm3 (0≤n<10, the same below), the amount of microbes decreased with the monthly dropping of seawater temperature and showed a state of diurnal variations. The seawater in the Bay has been fairly clean. The microbial community consisted of at least thirteen genera,in which pseudomonas was common. In the intertidal zone of the Deception Island,there were only a few CFU of bacteria per cubic meter in seawater; and n×10 CFU/g (w. w) in the surface sediment;and n×10 CFU/g(w. w) in the volcano ash.The results reveal the general features of the microbes from the air,sea and land in the South Shetland Islands, Antarctica. It provides data for further study of microbial resources in that area.