Veterinary and Agricultural Sciences Collected Works - Research Publications

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    A virally induced autoimmune reaction may be important in the pathogenesis of multiple sclerosis. The role that glycolipids and myelin basic protein presented to the virus may play in this process is considered. The most likely cells to be the source of autoantigens are neurons, myelin and oligodendrocytes. Viral infection of class II-expressing cells and association of the viral envelope autoantigens and the class II molecules could trigger an autoimmune reaction. It is suggested that for MS to develop following a virus infection the virus will need to cause expression of class II antigens on brain cells as well as fulfill the same role as an antigen presenting cell. The part which T-lymphotrophic viruses (HTLVs) and other enveloped viruses may play in this phenomenon is discussed.
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    Computer analysis suggests a role for signal sequences in processing polyproteins of enveloped RNA viruses and as a mechanism of viral fusion.
    Fazakerley, JK ; Ross, AM (Springer Science and Business Media LLC, 1989-05)
    We have used a computer program to scan the entire sequence of viral polyproteins for eucaryotic signal sequences. The method is based on that of von Heijne (1). The program calculates a score for each residue in a polyprotein. The score indicates the resemblance of each residue to that at the cleavage site of a typical N-terminal eucaryotic signal sequence. The program correctly predicts the known N-terminal signal sequence cleavage sites of several cellular and viral proteins. The analysis demonstrates that the polyproteins of enveloped RNA viruses--including the alphaviruses, flaviviruses, and bunyaviruses--contain several internal signal-sequence-like regions. The predicted cleavage site in these internal sequences are often known cleavage sites for processing of the polyprotein and are amongst the highest scoring residues with this algorithm. These results indicate a role for the cellular enzyme signal peptidase in the processing of several viral polyproteins. Not all high-scoring residues are sites of cleavage, suggesting a difference between N-terminal and internal signal sequences. This may reflect the secondary structure of the latter. Signal sequences were also found at the N-termini of the fusion proteins of the paramyxoviruses and the retroviruses. This suggests a mechanism of viral fusion analogous to that by which proteins are translocated through the membranes of the endoplasmic reticulum at synthesis.
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    An Introduction to Working Animals
    Falvey, JL (lindsay falvey, 1985)
    The book aimed to raise the profile of such economic outputs in development projects in poor countries where well-meaning but myopic development policies from international agencies assumed such animal products were of low value and would ...