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Rhesus Cytomegalovirus Is Similar to Human Cytomegalovirus in Susceptibility to Benzimidazole Nucleosides. Thomas W. North, 2004.Rhesus and human cytomegalovirus (RhCMV and HCMV, respectively) exhibit comparable inhibition by benzimidazole nucleosides, including 2,5,6-trichloro-(1-ß-D-ribofuranosyl)benzimidazole (TCRB), and pyrrolo[2,3-d]pyrimidines . The two HCMV protein targets of TCRB, UL89 and UL56, are highly conserved with their RhCMV homologues . These data indicate that infection of rhesus macaques with RhCMV represents a useful model to test novel anti-HCMV drugs . Endogenous Xylose Pathway in Saccharomyces cerevisiae. Mervi H. Toivari, 2004.The baker's yeast Saccharomyces cerevisiae is generally classified as a non-xylose-utilizing organism . We found that S . cerevisiae can grow on D-xylose when only the endogenous genes GRE3 (YHR104w), coding for a nonspecific aldose reductase, and XYL2 (YLR070c, ScXYL2), coding for a xylitol dehydrogenase (XDH), are overexpressed under endogenous promoters . In nontransformed S . cerevisiae strains, XDH activity was significantly higher in the presence of xylose, but xylose reductase (XR) activity was not affected by the choice of carbon source . The expression of SOR1, encoding a sorbitol dehydrogenase, was elevated in the presence of xylose as were the genes encoding transketolase and transaldolase . An S . cerevisiae strain carrying the XR and XDH enzymes from the xylose-utilizing yeast Pichia stipitis grew more quickly and accumulated less xylitol than did the strain overexpressing the endogenous enzymes . Overexpression of the GRE3 and ScXYL2 genes in the S . cerevisiae CEN.PK2 strain resulted in a growth rate of 0.01 g of cell dry mass liter–1 h–1 and a xylitol yield of 55% when xylose was the main carbon source . Functional Analysis of the Erwinia herbicola tutB Gene and Its Product. Takane Katayama, 2002.The tutB gene, which lies just downstream of tpl, has been cloned from Erwinia herbicola, and its product was analyzed . Despite its high sequence similarity to tryptophan transporters, TutB was found to be a tyrosine-specific transporter . Tryptophan acted as a competitive inhibitor of tyrosine transport . Unlike the tryptophanase operon, the tpl and tutB genes do not constitute an operon . Real-Time PCR for Quantification of Giardia and Cryptosporidium in Environmental Water Samples and Sewage. Rebecca A. Guy, 2003.The protozoan pathogens Giardia lamblia and Cryptosporidium parvum are major causes of waterborne enteric disease throughout the world . Improved detection methods that are very sensitive and rapid are urgently needed . This is especially the case for analysis of environmental water samples in which the densities of Giardia and Cryptosporidium are very low . Primers and TaqMan probes based on the ß-giardin gene of G . lamblia and the COWP gene of C . parvum were developed and used to detect DNA concentrations over a range of 7 orders of magnitude . It was possible to detect DNA to the equivalent of a single cyst of G . lamblia and one oocyst of C . parvum . A multiplex real-time PCR (qPCR) assay for simultaneous detection of G . lamblia and C . parvum resulted in comparable levels of detection . Comparison of DNA extraction methodologies to maximize DNA yield from cysts and oocysts determined that a combination of freeze-thaw, sonication, and purification using the DNeasy kit (Qiagen) provided a highly efficient method . Sampling of four environmental water bodies revealed variation in qPCR inhibitors in 2-liter concentrates . A methodology for dealing with qPCR inhibitors that involved the use of Chelex 100 and PVP 360 was developed . It was possible to detect and quantify G . lamblia in sewage using qPCR when applying the procedure for extraction of DNA from 1-liter sewage samples . Numbers obtained from the qPCR assay were comparable to those obtained with immunofluorescence microscopy . The qPCR analysis revealed both assemblage A and assemblage B genotypes of G . lamblia in the sewage . No Cryptosporidium was detected in these samples by either method .
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