Julia Elledge - Bacillus pumilus

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Classification

Domain: Bacteria

Kingdom: Eubacteria

Phylum: Firmicutes

Class: Bacilli

Order: Bacillales

Family: Bacillaceae

Genus: Bacillus

Species: B. Pumilus

Species

NCBI: Taxonomy

Bacillus pumilus

Habitat Information

B. pumilus can be found in a wide variety of soils, plants, and surfaces. My particular sample was found in an area of Lewisville soils and Urban land, with 0 to 2 percent slopes. The temperature and humidity when the sample was taken were 73º F and 22%. Pressure was 30.03 in. and the solar radiation was at 17.55 MJm2. There had been no rainfall in the previous 24 hours. The specific location was a grassy area between my apartment building and the parking lot. The address is 2703 Manor Rd, Austin, TX, 78722.

Description and Significance

Colonial morphology: B. pumilus colonies are opaque and off-white. They are roughly circular, but with an irregular margin, and have a slight filamentous appearance.

Cellular morphology: B. pumilus is a gram positive rod bacterium with endospores and peritrichous flagella.

It is being evaluated for use in the commercial production of cellulase, which is an enzyme that can convert cellulolytic (plant) materials into soluble sugars or solvents. [1]

Genome Structure

B. pumilus has a single circular chromosome. There are 3,681 protein genes and 93 RNA genes for a total of 3,704,465 nucleotides. 41% of its base pairs are G-C. [2]

Forward sequence: ACGGAGCAACGCCGCGTGAGTGATGAAGGTTTTCGGAT CGTAAAGCTCTGTTGTTAGGGAAGAACAAGTGCGAGAGTAACTGCTCGCACCTTGACGGTACCTAACCAGAAAGCCACGG CTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGCAAGCGTTGTCCGGAATTATTGGGCGTAAAGGGCTCGCAGGC GGTTTCTTAAGTCTGATGTGAAAGCCCCCGGCTCAACCGGGGAGGGTCATTGGAAACTGGGAAACTTGAGTGCAGAAGAG GAGAGTGGAATTCCACGTGTAGCGGTGAAATGCGTAGAGATGTGGAGGAACACCAGTGGCGAAGGCGACTCTCTGGTCTG TAACTGACGCTGAGGAGCGAAAGCGTGGGGAGCGAACAGGATTAGATACCCTGGTAGTCCACGCCGTAAACGATGAGTGC TAAGTGTTAGGGGGTTTCCGCCCCTTAGTGCTGCAGCTAACGCATTAAGCACTCCGCCTGGGGAGTACGGTCGCAAGACT GAAACTCAAAGGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGAAGCAACGCGAAGAACCTTACC AGGTCTTGACATCCTCTGACAACCCTAGAGATAGGGCTTTCCCTTCGGGGACAGAGTGACAGGTGGTGCATGGTTGTCGT CAGCTCGTGTCGTGAGATGTCATAGNCTGGTTTC

Reverse sequence: ACGGAGCAACGCCGCGTGAGTGATGAAGGTTTTCGGAT CGTAAAGCTCTGTTGTTAGGGAAGAACAAGTGCGAGAGTAACTGCTCGCACCTTGACGGTACCTAACCAGAAAGCCACGG CTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGCAAGCGTTGTCCGGAATTATTGGGCGTAAAGGGCTCGCAGGC GGTTTCTTAAGTCTGATGTGAAAGCCCCCGGCTCAACCGGGGAGGGTCATTGGAAACTGGGAAACTTGAGTGCAGAAGAG GAGAGTGGAATTCCACGTGTAGCGGTGAAATGCGTAGAGATGTGGAGGAACACCAGTGGCGAAGGCGACTCTCTGGTCTG TAACTGACGCTGAGGAGCGAAAGCGTGGGGAGCGAACAGGATTAGATACCCTGGTAGTCCACGCCGTAAACGATGAGTGC TAAGTGTTAGGGGGTTTCCGCCCCTTAGTGCTGCAGCTAACGCATTAAGCACTCCGCCTGGGGAGTACGGTCGCAAGACT GAAACTCAAAGGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGAAGCAACGCGAAGAACCTTACC AGGTCTTGACATCCTCTGACAACCCTAGAGATAGGGCTTTCCCTTCGGGGACAGAGTGACAGGTGGTGCATGGTTGTCGT CAGCTCGTGTCGTGAGATGTCATAGNCTGGTTTC

Cell Structure, Metabolism and Life Cycle

B. pumilus is a gram positive bacterium that forms endospores. It is motile due to peritrichous flagella, and aerobic, requiring oxygen for respiration. Based on the results of the phenol red broth tests, it can ferment sucrose and glucose, but not lactose. This was confirmed with positive result for mixed acid fermentation in the MR test (with the accompanying negative VP result). B. pumilus also tested positive for cytochrome c oxidase and catalase. It does not hydrolyze esculin in the presence of bile.

The life cycle of B. pumilus follows that of most spore-forming Bacillus species. It consists of three phases: vegetative growth, sporulation, and germination. The vegetative growth phase occurs when there are sufficient nutrients available to the organism. It grows by asexual reproduction, with each cell dividing. When the conditions become less favorable (lack of nutrients, wrong temperature, high cell density), some of the cells will enter the sporulation phase. They divert their resources into the production of an endospore. Then, once the environmental conditions are once again favorable, the spore enters the germination phase. The spore matures into a vegetative cell, and the process repeats.

Physiology and Pathogenesis

Tests for the presence of lipase and casease were negative, but B. pumilus did test positive for DNase. It does not hydrolyze starch or urea. It doesn't hydrolyze tryptophan either, and it cannot reduce sulfur. However, B. pumilus is motile. It cannot utilize citrate as a source of carbon, and it does not reduce nitrate.

Being gram positive, B. pumilus does not grow on Eosin Methylene Blue agar, Hektoen Enteric agar, or MacConkey agar. It cannot decarboxylate arginine, lysine, or ornithine, and it does not deaminate the amino acid phenylalanine.

B. pumilus does not grow on blood agar, or phenylethyl alcohol agar. It is not salt tolerant, so it will not grow on a Mannitol Salt agar or in a 6.5% NaCl broth.

Infection of B. pumilus in humans is very rare, but it is possible. Its presence in rice has cause three cases of food poisoning. [3] The symptoms included dizzyness, chills, stomach cramps, and diarrhea. There have also been three reported cases of cutaneous infection. [4] The lesions that developed were similar to those caused by a cutaneous anthrax infection.

In testing, B. pumilus showed susceptibility to a both Bacitracin and Optichin. Its growth is also inhibited by bleach, clove oil, and Lysol, but not lavendar oil.

B. pumilus can inhibit nematodes and fungal diseases once it colonizes a plant's root system. In fact, strain GB34 is used as an active ingredient in agricultural fungicides, so it has a significant environmental impact. [1]

References

1. http://www.ncbi.nlm.nih.gov/genome/?term=bacillus%20pumilus

2. http://www.genome.jp/kegg-bin/show_organism?org=bpu

Author

Page authored by Julia Elledge, student of Prof. Kristine Hollingsworth at Austin Community College.