Cytomegalovirus
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Classification: Cytomegalovirus (CMV) is a member of Betaherpesvirinae in the subfamily Herpesviridae. (emedicine)
Description and significance: Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.
Genome structure: There are many strains of CMV and each have different genotypes. Different strains share about 80% of the genome. CMV is a double-stranded linear DNA virus with 162 hexagonal protein capsomeres surrounded by a lipid membrane. CMV has the largest genome of the herpes viruses, ranging from 230-240 kilobase pairs. Of the betaherpesviruses, CMV is the only class E genome, making it similar to herpes simplex 1. Human CMV is composed of unique and inverted repeats that include the existence of 4 genome isomers caused by inversion of L-S genome components (class E). Replication may be divided into immediate early, delayed early, and late gene expression based on time of synthesis after infection. The DNA is replicated by rolling circles. In vitro, CMV replicates in human fibroblasts.(emedicine) Describe 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?
Cell structure and metabolism: Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.
Ecology: Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
Pathology: It is an enveloped DNA virus. When the host is infected, CMV DNA can be detected with polymerase chain reaction (PCR) in all the different cell lineages and organ systems in the body. Upon initial infection, CMV infects the epithelial cells of the salivary gland, resulting in a persistent infection and viral shedding.(emedicine) Clinically significant CMV disease most often develops in immunocompromised patients such as those with HIV,or those who have had organ or bone-marrow transplantations. When it is symptamatic, CMV can affect almost every organ of the body. This can result in fever of unknown origin, pneumonia, hepatitis, encephalitis, myelitis, colitis, uveitis, retinitis, and neuropathy. (emedicine) CMV, like other herpesviruses, can establish a latent infection in the host, where it remains dormant and does not cause symptoms to the host. (emedicine) Cell-mediated immunity is considered the most important factor in controlling CMV infection. Patients deficient in cell-mediated immunity are at greatest risk for CMV disease. CMV-specific CD4+ and CD8+ lymphocytes play an important role in immune protection after primary infection or reactivation of latent disease. Studies of bone marrow transplant patients have revealed that patients who do not develop CMV-specific CD4+ or CD8+ cells are at higher risk for CMV pneumonitis. Additionally, no cases of CMV pneumonia have been reported in allogeneic marrow transplant patients receiving infusions of CMV-specific CD8+ cells.(emedicine) 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:
[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. Retrieved from "http://en.citizendium.org/wiki/Biggius_microbia"
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