Geobacillus stearothermophilus (basonym Bacillus stearothermophilus ) is a Gram-positive, rod-shaped bacterium and member of the Firmicutes division. Bacteria are thermophils and are widely distributed in soils, hot springs, marine sediments, and are a cause of decay in food products. It will grow in the temperature range 30-75 degrees Celsius. Some strains are able to oxidize carbon monoxide aerobically. This is usually used as a challenge organism for sterilization validation studies and periodic sterilization cycle checks. Biological indicators contain spores of organisms on filter paper in bottles. After sterilization, the lid is closed, the growth media ampoule in the bottle is crushed and the whole vial is incubated. The discoloration and/or turbidity indicates the result of the sterilization process; no change indicates that the sterilization conditions are achieved, whereas spore growth indicates that the sterilization process has not been met. Recently, the fluorescent-tagged strain, Rapid Readout (tm), is used to verify sterilization, since blue fluorescence appears to appear about a tenth of the time required for pH indicator color changes, and inexpensive light sensors can detect colony growth.
Biological indicators are used in conjunction with chemical indicators and process indicators to validate the sterilization process.
It was first described in 1920 as Bacillus stearothermophilus, but, together with Bacillus thermoglucosidasius, it was reclassified as a member of the genus Geobacillus in 2001. [.
Video Geobacillus stearothermophilus
Polymerase
Recently, polymerase DNA derived from this bacterium, Bst polymerase, has become important in the application of molecular biology.
Bst polymerase has activity like helicase, making it capable of releasing DNA strands. The optimum functional temperature is between 60 and 65 ° C and denatured at temperatures above 70 ° C. These features make it useful in loop-mediated (LAMP) isothermal amplification. LAMP is similar to polymerase chain reaction (PCR) but does not require the high-temperature step (96 Â ° C) needed to denature the DNA.
Maps Geobacillus stearothermophilus
References
External links
- Type the strain Geobacillus stearothermophilus in Bac Dive - Metadatabase Bacterial Diversity
Source of the article : Wikipedia
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