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Mutation in Enterovirus 71 Capsid Protein VP1 Confers Resistance to the Inhibitory Effects of Pyridyl Imidazolidinone. Shin-Ru Shih, 2004.Enterovirus 71 is one of the most important pathogens in the family of Picornaviridae that can cause severe complications in the postpoliovirus era, such as encephalitis, pulmonary edema, and even death . Pyridyl imidazolidinone is a novel class of potent and selective human enterovirus 71 inhibitor . Pyridyl imidazolidinone was identified by using computer-assisted drug design . This virologic investigation demonstrates that BPR0Z-194, one of the pyridyl imidazolidinones, targets enterovirus 71 capsid protein VP1 . Time course experiments revealed that BPR0Z-194 effectively inhibited virus replication in the early stages, implying that the compound can inhibit viral adsorption and/or viral RNA uncoating . BPR0Z-194 was used to select and characterize the drug-resistant viruses . Sequence analysis of the VP1 region showed that the resistant variants differed consistently by seven amino acids in VP1 region from their parental drug-sensitive strains . Site-directed mutagenesis of enterovirus 71 infectious cDNA revealed that a single amino acid alteration at the position 192 of VP1 can confer resistance to the inhibitory effects of BPR0Z-194 . Global Gene Expression Profiles of the Cyanobacterium Synechocystis sp . Strain PCC 6803 in Response to Irradiation with UV-B and White Light. Lixuan Huang, 2002.We developed a transcript profiling methodology to elucidate expression patterns of the cyanobacterium Synechocystis sp . strain PCC 6803 and used the technology to investigate changes in gene expression caused by irradiation with either intermediate-wavelength UV light (UV-B) or high-intensity white light . Several families of transcripts were altered by UV-B treatment, including mRNAs specifying proteins involved in light harvesting, photosynthesis, photoprotection, and the heat shock response . In addition, UV-B light induced the stringent response in Synechocystis, as indicated by the repression of ribosomal protein transcripts and other mRNAs involved in translation . High-intensity white light- and UV-B-mediated expression profiles overlapped in the down-regulation of photosynthesis genes and induction of heat shock response but differed in several other transcriptional processes including those specifying carbon dioxide uptake and fixation, the stringent response, and the induction profile of the high-light-inducible proteins . These two profile comparisons not only corroborated known physiological changes but also suggested coordinated regulation of many pathways, including synchronized induction of D1 protein recycling and a coupling between decreased phycobilisome biosynthesis and increased phycobilisome degradation . Overall, the gene expression profile analysis generated new insights into the integrated network of genes that adapts rapidly to different wavelengths and intensities of light . Differences in Genetic and Transcriptional Organization of the glpTQ Operons between Haemophilus influenzae Type b and Nontypeable Strains. Xin-Ming Song, 2003.The glpTQ operon of Haemophilus influenzae type b (Hib) and nontypeable H . influenzae (NTHi) strains is highly conserved, except for a 1.4-kb glpTQ intergenic region that was found in most Hib strains . The presence of this intergenic region results in divergent glpTQ transcriptional profiles for Hib and NTHi where Hib strains appear to have evolved an alternative promoter for glpQ expression . Based on the intergenic region's low G+C content, we speculate that this DNA fragment was acquired by lateral transfer . 2-Hydroxypenta-2,4-dienoate Metabolic Pathway Genes in a Strong Polychlorinated Biphenyl Degrader, Rhodococcus sp . Strain RHA1. Masayuki Sakai, 2003.A gram-positive polychlorinated biphenyl (PCB) degrader, Rhodococcus sp . strain RHA1, metabolizes biphenyl through the 2-hydroxypenta-2,4-dienoate (HPD) and benzoate metabolic pathways . The HPD metabolic pathway genes, the HPD hydratase (bphE1), 4-hydroxy-2-oxovalerate aldolase (bphF1), and acetaldehyde dehydrogenase (acylating) (bphG) genes, were cloned from RHA1 . The deduced amino acid sequences of bphGF1E1 have 30 to 58% identity with those of the HPD metabolic pathway genes of gram-negative bacteria . The order of these genes, bphG-bphF1-bphE1, differs from that of the HPD metabolic pathway genes, bphE-bphG-bphF, in gram-negative degraders of PCB, phenol, and toluene . Reverse transcription-PCR experiments indicated that the bphGF1E1 genes are inducibly cotranscribed in cells grown on biphenyl and ethylbenzene . Primer extension analysis revealed that the transcriptional initiation site exists within the bphR gene located adjacent to and upstream of bphG, which is deduced to code a transcriptional regulator . The respective enzyme activities of bphGF1E1 gene products were detected in Rhodococcus erythropolis IAM1399 carrying a bphGF1E1 plasmid . The insertional inactivation of the bphE1, bphF1, and bphG genes resulted in the loss of the corresponding enzyme activities and diminished growth on both biphenyl and ethylbenzene . Severe growth interference was observed during growth on biphenyl . The growth defects were partially restored by the introduction of plasmids containing the respective intact genes . These results indicated that the cloned bphGF1E1 genes are not only responsible for the primary metabolism of HPD during growth on both biphenyl and ethylbenzene but are also involved in preventing the accumulation of unexpected toxic metabolites, which interfere with the growth of RHA1 . Coaggregation among Nonflocculating Bacteria Isolated from Activated Sludge. Anushree Malik, 2003.Thirty-two strains of nonflocculating bacteria isolated from sewage-activated sludge were tested by a spectrophotometric assay for their ability to coaggregate with one other in two-membered systems . Among these strains, eight showed significant (74 to 99%) coaggregation with Acinetobacter johnsonii S35 while only four strains coaggregated, to a lesser extent (43 to 65%), with Acinetobacter junii S33 . The extent and pattern of coaggregation as well as the aggregate size showed good correlation with cellular characteristics of the coaggregating partners . These strains were identified by sequencing of full-length 16S rRNA genes . A . johnsonii S35 could coaggregate with strains of several genera, such as Oligotropha carboxidovorans, Microbacterium esteraromaticum, and Xanthomonas spp . The role of Acinetobacter isolates as bridging organisms in multigeneric coaggregates is indicated . This investigation revealed the role of much-neglected nonflocculating bacteria in floc formation in activated sludge .
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