India is the first country outside Africa where an HIV-2 epidemic is running in parallel to an HIV-1 epidemic, resulting in a significant proportion of double infections. HIV is spreading rapidly, mainly by heterosexual contact, but also among intravenous drug users. Genetic analyses of the HIV variants circulating in India point towards HIV-1 and HIV-2 having been introduced into the country recently.
Knowing how mycobacteria exploit host cytokines to survive and which cytokines have important roles in host defense against mycobacteria should allow the use of these molecules in the treatment of mycobacterial infections. Both interleukin 2 and interferon γ have been used to treat patients with leprosy, and granulocyte-macrophage colony-stimulating factor is presently being administered to AIDS...
The rice blast fungus Magnaporthe grisea has an exquisite level of pathogenic specialization, allowing it to infect and colonize rice, subvert the metabolism of the host and spread to new hosts. Through a combination of cytology and molecular-genetic analysis, a picture is gradually emerging of the many interlinked processes that are required for successful infection of the plant.
Polyoma virus middle T antigen duplicates the actions of growth-factor receptors in binding the signalling molecules phosphatidylinositol 3'-OH kinase and Shc. These properties indicate that middle T is mitogenic and may be required to overcome inhibition of DNA replication during the lytic life cycle of the virus.
The ability of Mycobacterium tuberculosis to sustain a chronic infection and cause disease in a subset of those infected depends on its products - virulence factors - that enable the organism to enter and survive indefinitely inside mononuclear phagocytic cells by subverting cellular antimicrobial mechanisms. Characterizing these factors is essential to understanding the pathogenesis of M. tuberculosis.
Two of the three recently discovered aquatic morbilliviruses have been responsible for mass mortalities among marine mammals; both affect more than one host species, but susceptibility to infection varies considerably between species. Apparent differences between the dynamics of aquatic morbilliviruses and their terrestrial counterparts may be a consequence of high levels of interspecific transmission.
Although widely used, tissue-culture assays cannot be exact models of the conditions that are met in vivo by pathogenic bacteria. However, recent studies of specific mutants suggest that the model is good for highly invasive bacteria, but it remains to be seen if this is true for weakly invasive bacteria.
Adult periodontitis is a chronic inflammatory disease that affects over 49 million people in the USA alone. Porphyromonas (formerly Bacteroides) gingivalis, a Gram-negative anaerobe, has a diverse repertoire of virulence factors that may be involved in the induction or progression of periodontitis.
Since its discovery in 1957, Friend viral erythroleukemia has been the major model for understanding host genetic barriers to retroviral diseases and has facilitated the discovery of many polymorphic leukemia-control genes of mice. Some of these genes limit helper-virus replication, target-cell (erythroblast) pools or immune responses. At least one host gene appears to block the viral oncoprotein.
The cause of Borna disease, a neurological syndrome affecting mammals and birds, has recently been shown to be infection with an RNA virus. Molecular genetic analysis suggests that Borna disease virus represents a new viral taxon. It has a wide host range and is tropic for specific circuits in the central nervous system. There is indirect evidence that links it to diseases of the human central nervous...
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