Tina Torres Bacillus thuringiensis

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Classification

Domain: Bacteria, Phylum: Firmicutes, Class: Bacilli, Order: Bacillales, Family: Bacillaceae [Others may be used. Use NCBI link to find]

Species

NCBI: Taxonomy

Bacillus thuringiensis

Habitat Information

This soil sample was collected at 289 Spring Lane, Dripping Springs, TX 78620 Temperature: 60 F Humidity: 40% Wind Speed: NE 14G 22 mph Dewpoint: 35 F GPS coordinates: Latitude - 30.29001624465091, Longitude - -97.7299631715784

Description and Significance

When streaked on an LB plate, the colonies that formed were opaque in appearance and flat. When tested for antimicrobial properties the one antibiotic that showed the most susceptibility was Sulfisoxazole, also a small zone of inhibition was seen with Ampicillin. Linezolid and Cefamandole showed no zone of inhibition.

Bacillus thuringiensis is a gram positive, soil dwelling bacterium that is commonly used as a biological pesticide.

Genome Structure

This is the forward sequence I used to determine that my soil sample was Bacillus thuringiensis:

GACGGAGCAACGCCGCGTGAGTGATGAAGGCTTTCGGGTCGTAAAACTCTGTTGTTAGGGAAGAACAAGTGCTAGTTGAATAAGCTGGCACCTTGACGGTACCTAACCAGAAAGCCACGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGCAAGCGTTATCCGGAATTATTGGGCGTAAAGCGCGCGCAGGTGGTTTCTTAAGTCTGATGTGAAAGCCCACGGCTCAACCGTGGAGGGTCATTGGAAACTGGGAGACTTGAGTGCAGAAGAGGAAAGTGGAATTCCATGTGTAGCGGTGAAATGCGTAGAGATATGGAGGAACACCAGTGGCGAAGGCGACTTTCTGGTCTGTAACTGACACTGAGGCGCGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCGTAAACGATGAGTGCTAAGTGTTAGAGGGTTTCCGCCCTTTANTGCTGAAGTTAACGCATTAAGCACTCCGCCTGGGGAGTACGGCCGCAAGGCTGAAACTCNNAGGAATTGACNGGGGCCCGCACAANCGGTGGANCATGTGGTTTAATT ACCAGGTNTTGAAATCCTCTGANAACCCTANAGATACGGCNTCTCNCNTCTNNAACATANTGAC

Consists of a 5.5-Mb chromosome and nine plasmids.

This organism is gram positive and forms endospores.

It is also found naturally in the gut of caterpillars, moths and butterflies.

Cell Structure, Metabolism and Life Cycle

This gram positive microorganism has a thick, cross linked peptidoglycan layer in the bacterial cell wall. It is harmful to many insects which is why it is commonly used as a pesticide.

During sporulation it produces crystal proteins or endotoxins. It is also closely related to Bacillus anthrasis, which is the cause of anthrax.

Physiology and Pathogenesis

Using various biochemical tests I was able to determine the following about this organism:

Citrate: test used to test an organism's ability to use carbon as it's only source

        *soil sample - negative for citrate

SIM (Sulfar, Indole, Motility)

        *soil sample - negative for sulfar, indole and motility

Nitrate

        *soil sample - positive for nitrite reduction (nitrate --> nitrite)

Urea: tests an organism's ability to break down or convert urea to amonia

        *soil sample - negative for urea

TSI (Triple Sugar Iron)

        *soil sample - glucose fermentation with acid production

Decarboxylation: tests organism's ability to produce an enzyme called decarboxylase

        *soil sample - Argine: positive for decarboxylase
                       Lysine: positive for fermentation
                       Ornithine: positive for decarboxylase

Phenylalanine Deaminase: tests organism's ability to produce enzyme deaminase

        *soil sample - negative

Oxidase: identifies organisms that produce enzyme cytochrome oxidase, which participates in the electron transport chain

        *soil sample - positive for cytochrome oxidase

Hektoen Enteric Agar: this media is selective and differential that is used to isolate Salmonella and Shigella species

        *soil sample - negative and negative for fermentation

MacConkey Agar: selective and differential media that is used to isolate organisms based on their ability to ferment lactose

        *soil sample - negative and negative for fermentation

Eosin Methylene Blue Agar: selective and differential media used to isolate fecal coliforms

        *soil sample - positive for fermentation

Blood Agar: helps to determine the hemolytic capabilities of an organism

        *soil sample - alpha hemolysis (incomplete)

Mannitol Salt Agar: is selective for the genus Staphylococcus and differential for the fermentation of mannitol

        *soil sample - negative for fermentation, positive for growth

Phenylethyl Alcohol Agar: selective media used to grow gram positive organisms

        *soil sample - positive for growth

Catalase Test: enzyme (catalase) breaks down hydrogen peroxide to water and oxygen

        *soil sample - negative

6.5% Salt Tolerance: broth is made using tryptic soy broth and table salt to create high salt concentration, most organisms can't survive in high salt environments

        *soil sample - positive (turbid)

Bile Esculin Test: used to identify enterococci and group D streptococci based on their ability to hydrolize esculin

        *soil sample - positive for esculin hydrolysis

References

http://www.eol.org/pages/975750/overview

http://en.wikipedia.org/wiki/Bacillus_thuringiensis

Author

Page authored by Tina Torres, student of Prof. Kristine Hollingsworth at Austin Community College.