Listeria monocytogenes
A Microbial Biorealm page on the genus Listeria monocytogenes
Classification
Higher order taxa
Bacteria; Firmicutes; Bacilli; Bacillales; Listeriaceae; Listeria; L.monocytogenes
Species
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NCBI: Taxonomy |
Listeria Monocytogenes
Description and significance
Listeria monocytogenes are a Gram-positive rod-shaped bacterium that form single short chains (1), and can be resistant to the effects of freezing, drying, and heat (2) surprisingly well for a nonsporeforming bacterium. Listeria are mainly found in the soil, though Listeria monocytogenes, a pathogen, may specifically be found in raw foods, such as pasteurized fluid milk (5), raw vegetables, raw and cooked poultry (4). It has the ability to grow at low temperatures; thus, allowing it to grow in refrigerated foods. Listeria monocytogenes was thought to be exclusively associated as infections in animals, but recently, this pathogenic species has also been isolated, in its dormant form, in the intestinal tract of small percentage of the human population (3). Because Listeria monocytogenes is an agent of listeriosis, a serious disease where the overt form has a severe mortality greater than 25 percent (3), sequencing of the bacterium’s genome is of significant importance. Sequencing the genome of this organism allows for the measurement and study of traits such as new aspects regarding virulence and evolution using comparative genomics and DNA arrays (6). 16S rRNA cataloging studies have also been conducted to demonstrate Listeria monocytogenes’ close relationship to different stains of listeriae, based on genome size, GC-content and other various characters (7), which also helped place the bacterium within the bacterial phylogeny constructed by Woese (3).
Genome structure
Thermoplasma volcanium has a circular DNA with 1,584,804 nucleotides. It does not contain any plasmids. However, it possesses about 70 proteins not found in any other archaea’s genome.
Cell structure and metabolism
This microbe has a unique cell membrane that contains tetraether lipids. It lacks any kind of cell wall, which causes it to have irregular shapes and is capable of assuming different shapes. The microbe uses multiple flagella for high motility. Thermoplasma volcanium is heterotrophic and therefore requires it to obtain nutrients from other organisms especially those who cannot survive in acidic or high temperature environments. Depending on its living conditions, the microbe is both anaerobic and aerobic. It is anaerobic in the presence of elemental sulfur.
Ecology
Due to its evolutionary ties to eukaryotes, Thermoplasma genus can be used as model organism for researches.
Pathology
There is no known pathogen among different strains of Thermoplasma volcanium.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Current Research
Enter summaries of the most recent research here--at least three required
References
Edited by student of Rachel Larsen and Kit Pogliano
