Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To identify antigenic peptides of the parasite Cryptosporidium parvum, an expression library that allows for the production of chimeric proteins fused with a 6-histidine tag was made. The library was screened with C. parvum sporozoite rabbit anti-serum, and three positive clones (sa20, sa35, and sa40) were identified. The corresponding recombinant proteins (SA20, SA35, and SA40) were expressed in Escherichia coli and purified by metal-affinity chromatography. The sequence of sa20 and sa35 clones did not show any homology with known genes or proteins, whereas the 5' end of the sa40 clone showed homology with two previously identified C. parvum sequences. Hybridisations to intact chromosomes fractionated by pulsed-field gel electrophoresis revealed that the sa35 and sa40 sequences are localised on chromosome VII, whereas the sa20 sequence is localised on chromosome VI. Reverse transcriptase-PCR experiments showed the presence of mRNAs for sa35 and sa40 in the oocyst, whereas the sa20 mRNA was undetectable in this stage. The serological response to the three proteins was assayed in C. parvum-immunised rabbits and in immunocompetent individuals with cryptosporidiosis. The Western blot results indicated that rabbits, challenged with a sporozoite crude antigen or with an oocyst crude antigen, were highly responsive to these three antigens. Human serum samples showed a response to the three proteins, although the response to SA20 appeared to be unrelated to a recent C. parvum infection. These results suggest that the SA35 and the SA40 proteins may be useful in detecting C. parvum infections.
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PMID:Identification and characterisation of three antigenic proteins from Cryptosporidium parvum sporozoites using a DNA library expressing poly-histidine tagged peptides. 1096 48

Reoviruses are nonenveloped, segmented, double-stranded RNA viruses capable of infecting a wide range of invertebrate, vertebrate, fungus, and plant hosts. Though sporadic infection has been reported in a variety of reptilian species, infection of rough green snakes (Opheodrys aestivus) has not been previously described. Five wild-caught, adult rough green snakes were obtained by a zoological institution. Clinical deterioration was first noted in all snakes after 3 weeks in quarantine. Despite treatment, clinical decline progressed, and all 5 snakes died or were euthanized by 48 days post-arrival. Moderate, multifocal, acute, necrotizing hepatitis with hepatocellular syncytia was diagnosed in 1 snake. Two additional snakes had severe, diffuse, subacute to chronic pancreatitis. All 5 snakes had gastroenteric cryptosporidiosis. Electron microscopic examination of liver from the snake with hepatic lesions revealed scattered hepatocytes containing 1 or more intranuclear clusters of approximately 90 nm in diameter viral particles arranged in loose arrays. Polymerase chain reaction (PCR) amplification of a segment of the reovirus RNA-dependent RNA polymerase gene was performed on RNA extracted from tissues of all 5 snakes. PCR amplification of samples extracted from the snake with hepatic lesions resulted in a 109-base pair (bp) product. Phylogenetic analyses indicated the virus was a novel strain distinct from other reoviruses at a level consistent with species difference. The source of infection was unknown. PCR amplification of samples extracted from the other 4 snakes was negative.
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PMID:Orthoreovirus infection and concurrent cryptosporidiosis in rough green snakes (Opheodrys aestivus): pathology and identification of a novel orthoreovirus strain via polymerase chain reaction and sequencing. 2009 80