Pseudoalteromonas atlantica: Difference between revisions
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==Current Research== | ==Current Research== | ||
One recent research showed that the ECP of P. atlantica lead to fatality in edible crabs, Cancer Pagurus. ECP functions by causing rapid decline in the circulating hemocytes. The blood cells would begin to clump together(as shown in slide B). The diseased crabs show symptoms such as limb paralysis, eyestalk retraction, and marked decrease or lack of antennal sensitivity. These symptoms suggest an attack of the nervous system. ECP is not inactivated with high heat treatments or proteinase K digestion. The lipopolysaccharide(LPS) of Pseudoalteromonas atlantica was studied as a possible candidate for the main virulence factor. LPS was injected into healthy crabs and shown to cause the same symptoms and eventual death in an average of 90 minutes. However, with injection of LPS, no decline of hematocytes was observed. Instead of clumping, the hematocytes degranulated (shown in slide C) and eventually lysed. Results show that LPS from Pseudalteromonas atlantica is the main virulence factor for edible crabs. | |||
One most recent research on Pseudoalteromonas atlantica was done by Higgins, Carpenter, and Karls in the Department of Microbiology of the University of Georgia. These researchers found that the precise excision of mobile element IS492 on the P. atlantica chromosome regulated the EPS production on-off switch. | One most recent research on Pseudoalteromonas atlantica was done by Higgins, Carpenter, and Karls in the Department of Microbiology of the University of Georgia. These researchers found that the precise excision of mobile element IS492 on the P. atlantica chromosome regulated the EPS production on-off switch. |
Revision as of 07:19, 3 June 2007
Pseuderomonas Atlantica A Microbial Biorealm page on the genus Pseudoalteromonas atlantica
Classification
Higher order taxa
Bacteria; Proteobacteria; Gammaproteobacteria; Alteromonadales; Pseudoalteromonadaceae; Pseudoalteromonas Domain; Phylum; Class; Order; family [Others may be used. Use NCBI link to find]
Species
Pseudoalteromonas atlantica T6c Description and significance
Genome structureDescribe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle? The size of its genome is 5.187007 megabases, and its GC content is 45%. Cell structure and metabolismPseudoalteromonas is psychrotrophic, as well as chemoorganotrophic. It is capable of aerobic metabolism for energy, but not fermentation. Some important molecules it produces include acidic extracellular polysaccharide(EPS), enzymes that hydrolyze agar, alginate, and carrageenan(such as agarase), signalling molecules, such as homoserine lactones, and proteases. It produces EPS in large amounts in order to concentrate nutrients and provide substrates within its biofilm for other marine microorganisms. In order to do this, it gains energy for EPS production by colonizing solid surfaces quickly, using its secreted enzymes to process and take up substrates. Another interesting ability of this bacteria is that it has the ability to switch adhesin extracellular polysaccharide on and off. The on-off switch is essential to this bacteria's life cycle because of its need to migrate from open ocean to solid surface. Adhesins are switched off when the bacteria needs to loose its attachments to a solid surface and travel the ocean. Once a favorable surface is found, the bacteria needs adhesin for attachment. After attachment, it begins to form biolfilms. Pseudoalteromonas atlantica grows on D-glucose, D-mannitol, and maltose, and produces acid from glucose, maltose, galactose, and mannitol, and is capable of gelatin and casein hydrolysis. It can not metabolize DL-malate, D-sorbitol, or m-hydroxybenzoate, and does not perform nitrate reduction, indole production,anr argine dihydrolase activity. This particular strain is susceptible to all antibiotics. EcologyPseudoalteromonas atlantica's production of acidic extracellular polysaccharide in its biofim is particularly useful in bioremediation. The biofilm can be important in controlling toxic metal concentrations in marine environments because it can absorb 20-40% of trace metal lead. The bacteria has an unusual ability to regulate its EPS production. It has a DNA recombination system that involves reversible insertion of a mobile element, called IS 492. The insertion of IS 492 at an E{S site makes variable expressions of EPS possible. This system is responsive to changes in environmental conditions, therefore the bacteria can regulate its production of EPS in terms of the present environmental condition. PathologyPseudoalteromonas atlantica has been shown to cause shell disease-infected edible crabs. Studies show that the extracellular products or ECP of Pseudoalteromonas atlantica causes rapid death when injected into healthy crabs. The research is outlined in detail in the next section. There are no studies that show that Pseudoalteromonas atlantica is in any way harmful to humans. Current ResearchOne recent research showed that the ECP of P. atlantica lead to fatality in edible crabs, Cancer Pagurus. ECP functions by causing rapid decline in the circulating hemocytes. The blood cells would begin to clump together(as shown in slide B). The diseased crabs show symptoms such as limb paralysis, eyestalk retraction, and marked decrease or lack of antennal sensitivity. These symptoms suggest an attack of the nervous system. ECP is not inactivated with high heat treatments or proteinase K digestion. The lipopolysaccharide(LPS) of Pseudoalteromonas atlantica was studied as a possible candidate for the main virulence factor. LPS was injected into healthy crabs and shown to cause the same symptoms and eventual death in an average of 90 minutes. However, with injection of LPS, no decline of hematocytes was observed. Instead of clumping, the hematocytes degranulated (shown in slide C) and eventually lysed. Results show that LPS from Pseudalteromonas atlantica is the main virulence factor for edible crabs. One most recent research on Pseudoalteromonas atlantica was done by Higgins, Carpenter, and Karls in the Department of Microbiology of the University of Georgia. These researchers found that the precise excision of mobile element IS492 on the P. atlantica chromosome regulated the EPS production on-off switch. -frequency of transposase-dependent precise excision is very high -this results in nonmutagenic repair of donor DNA, which is unusual for transposable elemnts - ReferencesEdited by student of Rachel Larsen and Kit Pogliano |