Bacillus subtilis
A Microbial Biorealm page on the genus Bacillus subtilis
Classification
Domain: Bacteria Division/phylum: Firmicutes Class: Bacilli Order: Bacillales Family: Bacillaceae Genus: Bacillus Species: B. safensis
Genus
Bacillus safensis
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NCBI: Taxonomy |
Description and significance
Bacillus safensis is a Gram-positive, spore-forming, and rod bacterium. It is aerobic and highly resistant to UV and gamma rays and salt. It was first discovered in CAlifornia and Florida on spacecraft and so is believed to have been brought to the USA from Mars. There are numerous strains of this bacterium, everyone belonging to the Firmicutes phylum of Bacteria.
Genome structure
Bacillus safensis is a circular chromosome of 3.68 Mb, with approximately 3928 protein coding sequences and 39 contigs/overlapping DNA fragments greater than 200 base pairs in size. The genome also displays 73 tRNA genes. The strain FO-036b shows a guanine-cytosine content of 41.0-41.4 mol%.
Cell structure and metabolism
Bacillus safensis is an aerobic, mesophilic, gram positive, spore forming chemoheterotroph. Cell shape: rod Cell size: ranges from 0.5-0.7 μm in diameter and 1.0-1.2 μm in length Cell movement: motile, and use polar flagella for locomotion. Colony characteristics: dull white, undulate round, non-luminescent with irregular borders Growth: mesophillic, as they can grow in temperatures ranging between 10-50 °C. Salt tolerance: prefers 0-10% salt, and a pH of 4-8 Resistances: produce spores that are resistant to hydrogen peroxide and UV radiation.
Positive for oxidase and catalase, Vogues-Proskauer Negative for trypsin, mannitol, ed, but H2S, indole, amylase, agarase, lecithinase, DNase, urease, leucine arylamidase, cystine arylamidase, valine arylamidase, trypsin, α-galactosidase, N-acetyl-β-glucosamidase, α-fucosidase, tryptophan deaminase, phenylalanine deaminase, arginine dihydrolase, lysine decarboxylase and ornithine decarboxylase. Cells do not reduce nitrate, but do hydrolyse gelatin, aesculin and RNA. Negative for gas production from D-glucose. Acid is produced from D-glucose, glycerol, L-arabinose, ribose, D-xylose, galactose
Strain VK also contains genes that encode for 1-aminocyclopropane-1-carboxylate deaminase enzyme which enables the plant to tolerate salt, heavy metals, and polyaromatic hydrocarbons. Because it is so tolerant, Bacillus safensis VK is a powerful plant hormone producer.
Ecology
Because some strains of Bacillus safensis are resistant to UV rays, gamma rays and is highly salt resistant, it makes for a great plant growth-promoting rhizobacteria. This is very important in agriculture and crop health. Rhizobacteris is found on the root of the cumin plant.
Pathology
Bacillus safensis bacteria are non-pathogenic and are usually more helpful than harmful. The downside they present is that they can contaminate clean rooms (like NASA), where they can confuse test results. Certain strains are used on plants as way to stimulate root growth. Others are used to digest lipase.
Bacillus cereus. Bacillus cereus can cause gastrointestinal illness causing nausea, vomiting, severe cramping and diarrhea. It is often found in contaminated rice.
Bacillus subtilis can be used as a pesticide as it produces chemicals which are toxic to some insects,
Bacillus anthracis causes Anthrax. It was the first bacterial organism that was known to cause disease in humans. Bacillus anthracis spores can survive for very long periods of time are are often used for chemical warfare. Anthrax can be fatal and causes chest pain and high
Application to Biotechnology
Thirteen strains of a novel spore-forming, Gram-positive, mesophilic heterotrophic bacterium were isolated from spacecraft surfaces (Mars Odyssey Orbiter) and assembly-facility surfaces at the Jet Propulsion Laboratory in California and the Kennedy Space Center in Florida. Phylogenetic analysis of 16S rRNA gene sequences has placed these novel isolates within the genus Bacillus, the greatest sequence similarity (99.9 %) being found with Bacillus pumilus. However, these isolates share a mere 91.2 % gyrB sequence similarity with Bacillus pumilus, rendering their 16S rRNA gene-derived relatedness suspect. Furthermore, DNA–DNA hybridization showed only 54–66 % DNA relatedness between the novel isolates and strains of B. pumilus. rep-PCR fingerprinting and previously reported matrix-assisted laser desorption/ionization time-of-flight mass spectrometry protein profiling clearly distinguished these isolates from B. pumilus. Phenotypic analyses also showed some differentiation between the two genotypic groups, although the fatty acid compositions were almost identical. The polyphasic taxonomic studies revealed distinct clustering of the tested strains into two distinct species. On the basis of phenotypic characteristics and the results of phylogenetic analyses of 16S rRNA and gyrB gene sequences, repetitive element primer-PCR fingerprinting and DNA–DNA hybridization, the 13 isolates represent a novel species of the genus Bacillus, for which the name Bacillus safensis sp. nov. is proposed.
Current Research
Scientist Ram S. Singh and colleagues from the Punjabi University in India discovered one of the strains of Bacillus safensis to have unulase activity which is used for the production of high fructose corn syrup and fructooligosaccharides. This strain is found in the root tubers of asparagus plants.
Scientist Davender Kumar and his colleagues from Kurukshetra University in India found a strain of Bacillus safensis that was found to possess an enzyme for fat digestion called lipase. Lipases are also widely found in plants, microorganisms, and animals which are used in the production of bio deisel fuild, food, paper and detergents
Bharathiar University in India was able to isolate a strain of Bacillus safensis from soil samples contaminated with explosive residue. It has been cataloged but no use has been found for it yet.
References
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Edited by Margo Ucar, student of Rachel Larsen and Kit Pogliano
Edited by a student of M Glogowski at Loyola University
