Campylobacter jejuni
A Microbial Biorealm page on the genus Campylobacter jejuni
Classification
Higher order taxa
Kingdom: Bacteria, Phylum: Proteobacteria, Class: Epsilon Proteobacteria, Order: Campylobacterales, Family: Campylobacteraceae.
Species
Genus: Campylobacter, Species: C. jejuni.
Description and significance
Campylobacter jejuni is a gram negative bacteria that is curved and rod-shaped. It is most commonly found in animal feces, especially in wombat, kangaroo and bird feces. Campylobacter jejuni is a microaerophilic organism, this means that it requires an environment that contains reduced concentration of oxygen (~3-5% of oxygen and ~2-10% of carbon dioxide). Because of this requirement, it is very sensitive to stress in the environment. For example, too much oxygen, acidic condition, heating, and drying. Campylobacter jejuni is the number one cause of foodborn illness in the United States. Therefore, it is very important to sequence its genome to determine its role in these foodborne illnesses and effective treatments can be developed. Campylobacter jejuni is present in high levels in diarrhea stools of an infected individual as well as animal feces. This bacteria can be isolated from humans and animals. Isolation requires special antibiotic-containing media and an environment that contains optimal level of oxygen for microaerophilic organims.
Genome structure
The genome of Campylobacter jejuni consists of circular DNA and 1,616,554 nucleotides. It has 1707 genes and 1653 coding proteins. The GC content of Campylobacter jejuni is about 30% and the percentage coding of the bacteria is about 93%. The sequence of Campylobacter jejuni is variable. The eight distribution of variable sequences showed that they can use alternative terminal electron acceptor for oxygen. This represents the diverse life sources for Campylobacter jejuni. According to MLST type, the correlation of clonal complex and distribution of the genes is strong. However, these distribution of genes showed no evidence for their host preferences. Therefore, widespread horizontal gene transfer between clonal complexes is not supported.
Cell structure and metabolism
Campylobacter jejuni is a gram negative bacteria like bacilli. It is microaerophilic and non-fermentive organism. Its structure is similar to most gram negative bacteria. It has one flagellum at one pole or both poles of the cell. The cell contains an outer membrane and an inner membrane with periplasm in between the two membranes. The outer membrane consist of lipopolysaccharide which are endotoxic. Membrane proteins are embedded on the outer membrane surface, they are antigenic and are used for invation of the host. Campylobacter jejuni uses oxygen as its final electron acceptor. This is expected since it is a microaerophilic organism and it gows in its optimal rate with ~5% of oxygen level plus ~10% carbon dioxide. The bacteria is very sensitive to environmental stress such as heating, drying and over concentrated levels of oxygen.
Ecology
Campylobacter jejuni is an interesting bacteria because it resembls some eukaryotic-like system for N-linked protein glycosylation. Because there are limited experiments can be designed to isolated the glycosylate proteinis, little is known about the structual context of the glycosylated sequon. The disease Camylobacter jejuni caused is known as campylobacer enteritis or gasteroenteritis. The illness leads to severe diarrhea and fecal leukocytes. These symptoms are usually combined with fever, headaches and muscle pain. Children under 5 and young adults are more vulnerable to get the disease more than other groups. Although Campylobacter is the number one cause of foodborne illness, it is the least deadly. The case/fatality ratio is about 1/1000 which is very low.
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
Enter summaries of the most recent research here--at least three required
References
1) [http://en.wikipedia.org/wiki/Campylobacter_jejuni, "Campylobacter Jejuni" Wekipedia
2) [http://www.cfsan.fda.gov/~ebam/bam-7.html, Jan M. Hunt, Carlos Abeyta and Tony Tran, "Bacteriological Analytical Manual, 8th Edition, Revision A, 1998 Chapter 7" March 2001
3) [http://www.cfsan.fda.gov/~mow/chap4.html, "Foodborne Pathogenic Microorganisms and Natural Toxins Handbook" January 1992
Edited by LiJie Shi student of Rachel Larsen[lshi@ucsd.edu]
