Bacillus cereus biol 2402

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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

Genus: Bacillus

Species Group: Bacillus cereus group

NCBI: Taxonomy

Habitat Information

The dirt sample that the B. cereus came from was collected on September 3, 2015 in Lakeway, Texas. The dirt was in a shady area underneath some trees between a creek and a small field. It was 91 degrees Fahrenheit, 44% humidity, and had not rained in the past 24 hours. The dirt was collected from about 2 inches below the surface. Approximate grid coordinates from the NRCS soil map are 3359230 x 598060. Soil type according to the NRCS soil map is volente silty clay loam, 1 to 8% slopes.

Description and Significance

Describe the appearance (colonial and cellular), possible antimicrobial activity etc. of the organism, and why the organism might be significant.

Colony Appearance: Matte, white, flat colonies with irregular to lobate margins.
Cellular Appearance: Rod-shaped, endospore forming, and Gram-positive.

Genome Structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Include S Ribosomal sequence that you obtained from PCR and sequencing here.

GENOME OVERVIEW
The chromosome of B. cereus is circular with about 5,411,809 nucleotides [2].
The following make up the genomic structure of B. cereus [2]:

• 5481 genes
• 5234 protein coding genes
• 147 structural RNAs
• 5, 366 RNA operons

S RIBOSOMAL SEQUENCE
Through PCR, we determined that our soil organism's S Ribosomal sequence is:

Forward sequence:

 ACGGAGCACGCCGCGTGAGTGATGAAGGCTTTCGGGT
 CGTAAAACTCTGTTGTTAGGGAAGAACAAGTGCTAGTTGAATAAGCTGGCACCTTGACGGTACCTAACCAGAAAGCCACG
 GCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGCAAGCGTTATCCGGAATTATTGGGCGTAAAGCGCGCGCAGG
 TGGTTTCTTAAGTCTGATGTGAAAGCCCACGGCTCAACCGTGGAGGGTCATTGGAAACTGGGAGACTTGAGTGCAGAAGA
 GGAAAGTGGAATTCCATGTGTAGCGGTGAAATGCGTAGAGATATGGAGGAACACCAGTGGCGAAGGCGACTTTCTGGTCT
 GTAACTGACACTGAGGCGCGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCGTAAACGATGAGTG
 CTAAGTGTTAGAGGGTTTCCGCCCTTTAGTGCTGAAGTTAACGCATTAAGCACTCCGCCTGGGGAGTACGGCCGCAAGGC
 TGAAACTCAAAGGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGAAGCAACGCGAAGAACCTTAC
 CAGGTCTTGACATCCTCTGAAAACCCTAGAGATAGGGCTTCTCCTTCGGGAGCAGAGTGACAGGTGGTGCATGGTTGTCG
 TCAGCTCGTGCCGTGAGATGTCATANNNTNGTTTTCC

Reverse Sequence:

 ACCTGTCACTCTGCTCCCGAAGGAGAAGCCCTATCTCTAGGGTTTTCAGAGGATGTCAAGACCTGG
 TAAGGTTCTTCGCGTTGCTTCGAATTAAACCACATGCTCCACCGCTTGTGCGGGCCCCCGTCAATTCCTTTGAGTTTCAG
 CCTTGCGGCCGTACTCCCCAGGCGGAGTGCTTAATGCGTTAACTTCAGCACTAAAGGGCGGAAACCCTCTAACACTTAGC
 ACTCATCGTTTACGGCGTGGACTACCAGGGTATCTAATCCTGTTTGCTCCCCACGCTTTCGCGCCTCAGTGTCAGTTACA
 GACCAGAAAGTCGCCTTCGCCACTGGTGTTCCTCCATATCTCTACGCATTTCACCGCTACACATGGAATTCCACTTTCCT
 CTTCTGCACTCAAGTCTCCCAGTTTCCAATGACCCTCCACGGTTGAGCCGTGGGCTTTCACATCAGACTTAAGAAACCAC
 CTGCGCGCGCTTTACGCCCAATAATTCCGGATAACGCTTGCCACCTACGTATTACCGCGGCTGCTGGCACGTAGTTAGCC
 GTGGCTTTCTGGTTAGGTACCGTCAAGGTGCCAGCTTATTCAACTAGCACTTGTTCTTCCCTAACAACAGAGTTTTACGA
 CCCGAAAGCCTTCATCACTCACGCGGCGTTGCTCCGTCAGACTTTCGTCCATTGCGGAAGATTCCCTACTGCTGCCNCNC
 GTANAGTACTGG

Cell Structure, Metabolism and Life Cycle

Interesting features of cell structure; how it gains energy; what important molecules it produces.

Physiology and Pathogenesis

Biochemical characteristics, enzymes made, other characteristics that may be used to identify the organism; contributions to environment (if any).
If relevant, how does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

OVERVIEW
B. Cereus is motile, catalase positive, able to ferment glucose, unable to ferment lactose, able to reduce nitrate to non gaseous nitrogenous compounds, produces amylase, and has alpha hemolytic activity.

We tested our sample of B. cereus for antimicrobial sensitivity with bacitracin, optochin, nafcillin, novobiocin, cefoxitin, and oxacillin. Of all of those, only novobiocin was a successful antimicrobial and produced a zone of inhibition. We also tested four disinfectants, 70% isopropyl alcohol, 10% bleach, orange, and 100% lysol. Lysol was the only disinfectant that produced a zone of inhibition.

While B. cereus is associated mainly with food poisoning, it is being increasingly reported to be a cause of serious and potentially fatal non-gastrointestinal-tract infections.The pathogenicity of B. cereus, whether intestinal or nonintestinal, is intimately associated with the production of tissue-destructive exoenzymes. Among these secreted toxins are four hemolysins, three distinct phospholipases, an emesis-inducing toxin, and proteases. [1].

BIOCHEMICAL TEST RESULTS

• Phenol Red Broth: glucose: positive; lactose: degradation of peptone, alkaline end products; sucrose: degradation of peptone, alkaline end products
• Starch Hydrolysis: positive
• Casein Hydrolysis: slight positive
• Gelatin Hydrolysis: positive
• DNA Hydrolysis: negative
• Lipid Hydrolysis: negative
• Methyl Red: negative
• Voges Proskauer: negative
• Citrate Test: negative
• SIM Tests: negative for sulfur reduction, positive for motility
• Nitrate Reduction: organism reduced nitrate to nongaseous nitrogenous compounds
• Urea Hydrolysis: negative
• Triple Sugar Iron Agar: negative for fermentation and sulfur reduction; peptone was catabolized aerobically with alkaline products

References

[1] Bottone, E. (2010). Bacillus cereus, a Volatile Human Pathogen. CMR, 382-398. doi:10.1128

[2] "Bacillus cereus". MicrobeWiki site. Accessed December 3, 2015.

Author

Page authored by Zaneta Wu and Desiree Weinstock, students of Prof. Kristine Hollingsworth at Austin Community College.