Mycobacterium smegmatis

From MicrobeWiki, the student-edited microbiology resource

A Microbial Biorealm page on the genus Mycobacterium smegmatis

Classification

Higher order taxa

Bacteria (Domain); Actinobacteria (Phylum); Actinobacteridae (Class); Actinomycetales (Order); Corynebacterineae (Suborder); Mycobacteriaceae(Family); Mycobacterium (Genus)

Species

Mycobacterium smegmatis.

Also known by: Mycobacterium paratuberculosis smegmatis, Bacterium smegmatis, Bacillus smegmatis, Mycobacterium paratuberculosis smegmatis, Bacterium smegmatis, Bacillus smegmatis, Mycobacterium smegmatis.

Description and significance

Mycobacterium smegmatis was first discovered in 1884 by Lustgarten. They are mostly found in the soil, marine, and freshwater environments. Mycobacterium smegmatis is classified as a saprophytic species that rarely causes disease and isn't dependent on living in an animal, unlike some pathogenic Mycobacterium. It is a very important bacteria because it is very useful for studying cultures of Mycobacterium. There are several Mycobacterium species that are harmful and are common diseases, like Mycobacterium leprea, Mycobacterium tuberculosis, and Mycobacterium bovis. Mycobacterium smegmatis is so important because it is fast growing and non-pathogenic compared to these species. Currently, there are many laboratories that are culturing this species to determine the pathological course of deleterious Mycobacteria.

Describe the appearance, habitat, etc. of the organism, Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.


Bacillus licheniformis is a bacterium that is commonly found in soil and bird feathers. Birds that tend to stay on the ground more than the air (i.e. sparrows) and on the water (i.e. ducks) are common carriers of this bacterium; it is mostly found around the bird's chest area and back plumage.

Bacillus licheniformis is part of the subtilis group along with Bacillus subtilis and Bacillus pumilus. These bacteria are commonly known to cause food poisoning and food spoilage. Bacillus licheniformis also is known for contaminating dairy products. Food borne outbreaks usually involve cases of cooked meats and vegetables, raw milk, and industrially produced baby food contaminated with Bacillus licheniformis.

Genome structure

The genome is 6,988,209 nucleotides long. It has a 67% GC content and a 33% AT content. 90% of the genome represents coding regions that encode for 6718 proteins. There are 6938 genes that are composed circularly. It doesn't contain any plasmids.

Other interesting features? What is known about its sequence?

Cell structure and metabolism

Mycobacterium smegmatis is a Gram-positive bacteria, characterized by an inner cell membrane and a thick cell wall. The Gram-positive bacteria is further classified as one with a high GC content and therefore a low AT content. This quality is used as a rude measure of similarity of different species of bacteria. Although this bacteria is Gram-positive, its cell wall contains mycolic acids, long, branched fatty acids that are normally present in Acid-fast bacteria. The acids prevent proper gram staining that would normally identify the cell as a gram positive cell because they create a waxy coating so the crystal violet has difficulty entering the cell, therefore making it seem gram negative.

Although it contains the similar structural features of Mycobacterium Tuberculosis, it grows much quicker in comparison. Mycobacterium smegmatis is an aerobic organism. It may grow on common substrates like sugars, organic acids, alcohols, and hydrocarbons. Small amounts of Mycobacterium smegmatis may also survive on chemolithoautotrophic growth on carbon dioxide and hydrogen gas. It requires a unique fatty acid biosynthesis to produce the mycolic acids that are present on the cell wall.

what important molecules it produces.

Ecology

Mycobacterium smegmatis may live in soil and degrade organic materials, including sterols. The bacteria lives in water, and tends to exist near large bodies of water.

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Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

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References

Dastur, A., Kumar, P., Ramesh, S., Vasanthakrishna, M., Varshney, U. "Analysis of the initiator tRNA genes from a slow- and a fast-growing Mycobacterium" Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560 012, India. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12209262&dopt=Abstract

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by Benjamin Yip, student of Rachel Larsen and Kit Pogliano