User:HilbrichS

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A Microbial Biorealm page on the genus HilbrichS

Classification

Higher order taxa

Bacteria; Proteobacteria; Delta/Epsilon subdivision; Campylobacterales; Campylobacteraceae [NCBI]

Species

C. coli, C. concisus, C.curvus, C.fetus subsp. fetus, C. fetus subsp venerealis, C. gracilis, C. helveticus, C.hominis, C. hyointestinalis subsp hyointestinalis, C. hyointestinalis subsp lawsonii, C.jejuni subsp doylei, C. jejuni jejuni, C. lanienae, C.lari, C. mucosalis, C.rectus, C. showae, C. spoterum, C. upsaliensis, B. ureolyticus [Ketley, Julian M., and Michael E. Konkel. Campylobacter: Molecular and Cellular Biology. Wymondham, UK: Horizon Bioscience, 2005. Print]



Campylobacter

Description and significance

Campylobacter is microaerophilic meaning it needs oxygen to survive, but the level of oxygen must be lower than the atmospheric levels. Too much oxygen and the bacterium could be killed. It is spiral in shape, a flagellate, and is very fragile. Campylobacter can be killed in high levels of oxygen or drying. Most Campylobacter is found within the intestinal tract of animals such as dogs, cats, poultry, swine, cattle, monkeys, rodents, wild birds, and even within humans. In humans the bacteria can live and survive without causing illness although often it does. The bacteria cycles through the environment by traveling through the intestinal tracts of animals and exiting the body through feces. The feces is then incorporated into the soil which maintains the low level of oxygen. The animals eat plants and sometimes soil containing the bacteria and the cycle continues. Campylobacter can be found in untreated water that is contaminated with fecal matter and therefore contributes to the cycle of the bacteria. [1] and [2]

Genome structure

Campylobacter species have varying genomes, but one of the most common species that affects humans and livestock is Campylobacter jejuni. Using C. jejuni as an example for the genomic structures, it has a circular chromosome made up of 1.6 million base pairs. The large number of base pairs allows for C. jejuni to code for 1,654 proteins that lead to 54 RNA species that are stable. The C. jejuni species genome is unusual because there is no insertion sequence or phage- associated sequence within it. Within the genome, there is also very little repetition of sequences, but hypervariable regions have been found. The short sequences of homopolymeric nucleotides that are varaible, are often found in regions that code for biosynthesis or for modification to the cell surface structures. It is believed that the hypervariability of the short runs is one of C. jejuni's main survival strategy. [3]

Cell structure and metabolism

Interesting features of cell structure; how it gains energy; what important molecules it produces. Campylobacter are microscopic helically-shaped cells. They look to have a "gulled-wing" appearance due to their spiral shape. Campylobacter have flagella and are describes as having rapid darting motility due to a long polar flagellum at either one or both ends of the cell. The flagellum is very long, often several times the longer than the length of the cell. Motility is slower in a wet environment due to it's sensitivity to levels of oxygen. Campylobacter has an outer covering of lipopolysaccharides due to its Gram negative protperty. The cell surface contains porins that are associated with the peptidoglycan layer as well as adhesive binding proteins. The cells can morph to cocci or elongated cells if left in a prolonged culture, or are exposed to oxygen. [4]

Campylobacter produces oxidase and catalase as a result of metabolism. It does not utilize carbohydrates for metabolism and are super sensitive to free radicals as well as superoxides. Not only are they sensitive to superoxides and free radicals, but also chemical and physical agents. [5]

Ecology

Campylobacter typically colonizes in the mucous overlying the mucosal surfaces of mammals and birds. The mucous allows the cells to dart about by using their flagella to maintain a colony within a mucosal flow. Most species of Campylobacter are thermophilic, such as C. jejuni. C. jejuni colonizes in mucous lining in the intestines of birds, specifically the cecum of birds which is roughly 42 degrees Celsius. Campylobacter is usually isolated to chickens and other birds and is passed from bird to bird by a common water source, but it can also inhibit other animals that have a lower body temperature or individuals with a weak immune system. Although Campylobacter are typically found in their intestinal niches, it can also be found isolated from fecal contamination. The fecal contamination can occur in water and food products like meat and milk causing humans to become infected. Although Campylobacter can be found in other environments, it is mostly found within the intestines of mammals and birds. [Dworkin, Martin M., and Stanley Falkow. Proteobacteria: Delta and Epsilon Subclasses, Deeply Rooting Bacteria. New York, NY: Springer, 2006. Print.] [6]

Pathology

Illness caused by Campylobacter is usually caused by the ingestion of a contaminated food product like meat or milk, or by drinking contaminated water. Two of the most common pathologies caused by Campylobacter are Gastroenteritis, also called Campylobacteriosis, and Guillain-Barre Syndrome (GBS). Gastroenteritis is caused primarily by C.jejuni and C. coli but can be attributed to others too. It is an inflammatory bacterial diarrhea which causes damage to the mucosal surface layer of the intestine divisions of the jejenum, ileum, and colon. The symptoms are diarrhea, malaise (fatigue), fever, abdominal pain with nausea but no actual vomiting. Onset of the symptoms occur after an incubation period of 1 to 7 days. The first symptoms to appear are abdominal cramps and diarrhea. There are also other less common symptoms that can be associated with Gastroenteritis which affect roughly 1/3 the patient population. The less common symptoms are prodronal fever, headache, dizziness, myalagia. The symptoms previously mention mimic flu-like symptoms, but will occur within 12-24 hours prior to intestinal symptoms. The diarrhea symptoms can range in severity from loose stool, to intense water diarrhea that can account for up to 10 bowl movements a day. Stool may often contain mucous or blood depending on the severity of the case. Normally the symptoms will subside in a few days to a week. Late onset of gastroenteritis can lead to complications such as Guillain-Barre Syndrome. Guillain-Barre Syndrome (GBS) is a reactive autoimmune disease that is self-regulated. GBS is mostly associated with C.jejuni. GBS targets the Schwann-cells and myelin by causing acute inflammatory demyelinating neuropathy due to a cross reaction. The axons of nerve cells may also be targeted by GBS and are affected by molecular mimicry of axonal membranes. [7]

Current Research and or Application to Biotechnology

Enter summaries of the most recent research and/or application to biotechnology here--at least three required

References

[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 student of Dr. Lynn M Bedard, DePauw University http://www.depauw.edu

Dworkin, Martin M., and Stanley Falkow. Proteobacteria: Delta and Epsilon Subclasses, Deeply Rooting Bacteria. New York, NY: Springer, 2006. Print.

Nachamkin, Irving, and Martin J. Blaser. Campylobacter. Washington, D.C.: ASM, 2000. Print.