Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The hrmA locus, isolated from Pseudomonas syringae pv. syringae 61, is essential for phenotypic expression of the P. s. pv. syringae 61 hrp cluster in Escherichia coli strains and enables bacteria carrying the hrp/hrm gene cluster to elicit the hypersensitive response (HR) associated with plant disease resistance. The phenotype of P. s. pv syringae 61 hrmA mutants (pathogenicity+, delayed HR) was distinct from that of hrp mutants. The locus was localized to a 3.6-kb BamH1-EcoR1 fragment whose nucleotide sequence was determined. A single open reading frame was identified that encodes for a 41,457-Da protein of unknown biochemical function. Production of the deduced protein product was confirmed by using T7 RNA polymerase-directed expression of the locus and N-terminal sequence analysis of the isolated HrmA. The deduced protein product did not exhibit homology with any of the characterized avr genes or the hrpN product of Erwinia amylovora. Transcription was shown to initiate 37 nucleotides upstream of the translational start from an apparent sigma 70 promoter. Two hrp genes were shown to act as positive transcriptional factors for hrmA expression. Expression of hrmA in P. syringae pv. glycinea race 4 did not exhibit the phenotypic properties of an avr gene or HrpN, but suggested that this locus may serve a regulatory function. A homolog to hrmA was present in strains of only three of the 23 P. syringae pathovars tested.
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PMID:Nucleotide sequence and properties of the hrmA locus associated with the Pseudomonas syringae pv. syringae 61 hrp gene cluster. 827 70

Zwittermicin A is a novel aminopolyol antibiotic that represents a new structural class of antibiotic and has diverse biological activities, including the suppression of plant disease and the ability to inhibit prokaryotic and eukaryotic cells. To enhance our fundamental understanding and applications of zwittermicin A, we elucidated mechanisms of zwittermicin A resistance in Escherichia coli. Two classes of zwittermicin A-resistant mutants of E. coli were selected and characterized. One class included mutants altered in hemA, hemB, hemL, ubi, cydAB or atp, which were defective in generating a proton motive force (PMF) and resistant to aminoglycosides. The mutant analysis, coupled with physiological data, indicated an association between the electrical membrane potential (deltapsi) component of PMF and zwittermicin A sensitivity. A second class of zwittermicin A-resistant mutants was aminoglycoside sensitive and was affected in rpoB and rpoC, genes that encode subunits of RNA polymerase. The rpoB and rpoC mutants suggested that zwittermicin A might inhibit transcription, DNA replication, DNA gyrase or topoisomerase I; however, we found no further evidence to support any of these as the target for zwittermicin A. This study elucidated the genetic mechanisms of zwittermicin A resistance in E. coli. The results suggest that deltapsi drives zwittermicin A uptake, and that, unlike other antibiotics for which resistance maps in rpoB or rpoC, zwittermicin A does not cause the rapid cessation of DNA or RNA synthesis, suggesting a unique mechanism of antibiosis.
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PMID:Genetic analysis of zwittermicin A resistance in Escherichia coli: effects on membrane potential and RNA polymerase. 948 87

The Fusarium solani species complex (FSSC) is the most common group of fusaria associated with superficial and life-threatening infections in humans. Here we formally introduce Fusarium metavorans sp. nov., widely known as FSSC6 (Fusarium solani species complex lineage 6), one of the most frequent agents of human opportunistic infections. The species is described with multilocus molecular data including sequences of internal transcribed spacer region (ITS), portions of the translation elongation factor 1-a gene (TEF1), and the partial RNA polymerase II gene (rPB2). A phylogenetic approach was used to evaluate species delimitation. Topologies of the trees were concordant. Phylogenetic analyses suggest that the FSSC consists of three major clades encompassing a large number of phylogenetic species; Fusarium metavorans corresponds to phylogenetic species 6 within FSSC clade 3. The species has a global distribution and a wide ecological amplitude, also including strains from soil and agents of opportunistic plant disease; it was also isolated from the gut of the wood-boring cerambycid beetle Anoplophora glabripennis.
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PMID:Fusarium metavorans sp. nov.: The frequent opportunist 'FSSC6'. 2953 34

A survey to determine the prevalence of potyviruses on yams, Dioscorea alata and D. cayenensis-rotundata, was undertaken in Colombia. Two hundred fifty leaf samples showing mottling symptoms were collected on the Atlantic coast and analyzed by antigen-coated plate enzyme-linked immunosorbent assay with universal potyvirus monoclonal antibodies (Agdia, Elkhart, IN). Potyviruses were detected in 70% (165/235) of the D. alata and in 66% (10/15) of the D. cayenensis-rotundata samples. The presence of Yam mild mosaic virus (YMMV) was indicated in some of these samples by immunocapture reverse-transcriptase polymerase chain reaction performed as previously reported (1). A 600-bp fragment that included the core and C-terminal region of the coat protein gene (CP) and the 3' untranslated region (3'UTR) was amplified from a D. alata isolate using universal potyvirus primers (1), cloned, and sequenced (EMBL Acc. AJ311725). Comparison with the two previously published YMMV sequences revealed 96.1 and 97.4% identity for the deduced amino acid sequence in the CP region, 74.1 and 83.2% nucleotide identity in the 3'UTR for Papua New Guinea (AB022424 [2]) and Martinique (AJ250336) isolates, respectively. YMMV is known to be widespread on D. alata in Africa and the South Pacific and has been recently identified in the Caribbean (1). To our knowledge, this is the first report of its occurrence in Colombia. A study of its incidence and genetic diversity in South America has been undertaken. References: (1) M. Bousalem and S. Dallot. Plant Disease 84:200, 2000. (2) S. Fuji et al. Arch Virol. 144:1415, 1999.
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PMID:Occurrence of Potyviruses on Yam (Dioscorea spp.) in Colombia and First Molecular Characterization of Yam mild mosaic virus. 3082 20