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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

virR is the central regulatory locus required for coordinate temperature-regulated virulence gene expression in the human enteric pathogens of Shigella species. Detailed characterization of VirR+ clones revealed that virR consisted of a 411 bp open reading frame (ORF) that mapped to a chromosomally located 1.8kb EcoRI-AccI DNA fragment from Shigella flexneri. Insertional inactivation of the virR ORF at a unique HpaI restriction site resulted in a loss of VirR+ activity. The virR ORF nucleotide sequence was virtually identical to the Escherichia coli hns gene, which encodes the histone-like protein, H-NS. Based on the predicted amino acid sequence of E. coli H-NS, only a single conservative base-pair change was identified in the virR gene. An additional clone, designated VirRP, which only partially complemented the virR mutation, was also characterized and determined by Southern hybridization and nucleotide sequence analysis to be unique from virR. Subclone mapping of this clone indicated that the VirRP phenotype was a result of the multiple copy expression of the S. flexneri gene for tRNA(Tyr). These data constitute the first direct genetic evidence that virR is an analogue of the E. coli hns gene, and suggest a model for temperature regulation of Shigella species virulence via the bacterial translational machinery.
Mol Microbiol 1992 Aug
PMID:Temperature regulation of Shigella virulence: identification of the repressor gene virR, an analogue of hns, and partial complementation by tyrosyl transfer RNA (tRNA1(Tyr)). 140 52

The adherence mechanisms of enteropathogenic Escherichia coli (EPEC) to epithelial cells are still not understood. To study the molecular basis of the diffuse adherence (DA) phenotype exhibited by diarrhoeagenic E. coli expressing classical EPEC serotypes we investigated strain 2787 (O126:H27) isolated from a case of infantile diarrhoea. A 6.0 kb plasmid-derived DNA fragment mediates the DA phenotype and encodes the 100 kDa adhesin protein AIDA-I (adhesin involved in diffuse adherence). Sequencing of the entire fragment revealed two open reading frames which encoded proteins of 45 kDa and 132 kDa, respectively. The 132 kDa protein has been identified as an AIDA-I precursor protein. After cleavage of the signal sequence further processing at the C-terminus of the 132 kDa precursor leads to the mature approximately 100 kDa AIDA-I. While the exact function of the cytoplasmic 45 kDa protein is not known, preliminary evidence indicates that it is necessary for the correct maturation of AIDA-I. The AIDA-I precursor exhibits significant homology with the virG(icsA) protein of Shigella flexneri which seems to be involved in the intercellular spread of invasive Shigella organisms.
Mol Microbiol 1992 Jun
PMID:AIDA-I, the adhesin involved in diffuse adherence of the diarrhoeagenic Escherichia coli strain 2787 (O126:H27), is synthesized via a precursor molecule. 162 82

Detection of pathogens (Legionella species) and indicator bacteria (coliform bacteria) was achieved by multiplex (simultaneous) PCR amplification of diagnostic gene sequences and by hybridization to immobilized poly-dT-tailed capture probes using a dot- or slot-blot approach. Complex manipulations of primer concentrations and staggered additions of primers were required in order to achieve equal amplification of multiple genes. Multiplex PCR amplification of two different Legionella genes, one specific for L. pneumophila (mip) and the other for the genus Legionella (5S rRNA), was achieved by staggered amplification. Multiplex PCR amplification using differing amounts of primers specific for lacZ and lamB genes permitted the detection of coliform bacteria and those associated with human faecal contamination, including the indicator bacterial species E. coli and enteric pathogens Salmonella and Shigella. Hybridization of biotin-labelled amplified DNA, in which the biotin was incorporated during PCR amplification from biotinylated-dUTP, to immobilized 400-dT-tailed capture probes permitted specific and sensitive detection of target gene sequences. The sensitivity of colorimetric detection achieved by PCR amplification of target DNA was at a level equivalent to 1-2 bacterial cells, which is the same level of sensitivity obtained with radioactive detection. The simultaneous amplification of several genes and hybridization to immobilized capture probes with colorimetric detection is an effective, efficient and rapid detection method for various human bacterial pathogens.
Mol Cell Probes 1990 Oct
PMID:Multiplex PCR amplification and immobilized capture probes for detection of bacterial pathogens and indicators in water. 228 Jul 81

Iron limitation, a condition encountered within mammalian hosts, induces the synthesis of a number of proteins in pathogenic Shigella species. These include several outer membrane proteins, Shiga toxin, and proteins involved in the biosynthesis and transport of high-affinity iron-binding compounds or siderophores. Although siderophores have been shown to play a major role in the virulence of some bacterial pathogens, these compounds do not appear to be essential for the virulence of Shigella species. Unlike those pathogens which are restricted to the extracellular compartments of the host, the Shigella species invade and multiply within host cells. Alternative iron-acquisition systems, such as the ability to utilize haem-iron, permit growth of the intracellular bacteria. Virulent shigellae also possess a cell-surface haem-binding protein, and synthesis of this protein correlates with infectivity and virulence. This protein does not appear to be involved in iron acquisition. Rather, it may allow the bacteria to coat themselves with haem compounds, thus enhancing their ability to interact with target host cells.
Mol Microbiol 1989 Sep
PMID:Iron and virulence in Shigella. 267 8

We have constructed a novel promoter probe plasmid pSB40, containing a unique lac-alpha-tetracycline marker gene tandem, which allows for both positive and negative selection of active promoters. Promoters cloned in pSB40 can be readily mobilized as EcoRI cassettes. Using this vector we have performed a non-invasive analysis of the E. coli chromosome for promoters regulated by osmotic upshift. Only one such promoter, subsequently identified as part of the proU operon, was isolated. A sequence of 253 bp, sufficient to mediate osmotic regulation of the proU promoter, was defined. This E. coli promoter was normally regulated in Salmonella typhimurium, Klebsiella and Citrobacter but not in Shigella. A proU-luxAB fusion plasmid was constructed and used to monitor in vivo real-time kinetics of proU induction following osmotic upshock.
Mol Microbiol 1989 Aug
PMID:A novel, non-invasive promoter probe vector: cloning of the osmoregulated proU promoter of Escherichia coli K12. 269 37

Enterotoxigenic Escherichia coli (ETEC) and Shigella account for a substantial proportion of acute diarrhoeal illnesses among Third-World children. Rapid detection of these infectious agents in faeces followed by the prompt implementation of public health measures could help reduce their spread during the early phase of epidemics. Towards this end, three pairs of synthetic oligonucleotide primers were prepared and shown to hybridize specifically to the genes encoding the heat-stable (ST) and the heat-labile (LT) enterotoxins of ETEC and to invasion-associated loci (ial) of the large Shigella virulence plasmid. When the three primer pairs were used together in the polymerase chain reaction (PCR), the three corresponding genetic loci could be simultaneously amplified using DNA extracted directly from stool; the amplified products were readily detected by ST-, LT- and ial-specific, alkaline phosphatase-labelled oligonucleotide probes (AP probes). The performance of this system was evaluated in a Mayan community in southeastern Mexico, where diarrhoeal illnesses are a common cause of childhood morbidity and mortality. Using only simple and inexpensive laboratory equipment, multigene amplification with these primers and probes led to the identification of ETEC and/or Shigella in the stools of 20 out of 71 children with diarrhoea; the procedure could be completed in seven hours and was more sensitive than conventional diagnostic tests or DNA probes used without amplification.
Mol Microbiol 1989 Dec
PMID:Multi-gene amplification: simultaneous detection of three virulence genes in diarrhoeal stool. 269 45

Shigella pathogenicity is a multi-genic phenomenon involving the participation of genes on both the 230 kilobase virulence plasmid and the chromosome. A key feature of the regulation of Shigella virulence is its response to growth temperature. Genes in the virulence regulon are fully expressed at 37 degrees C, the normal temperature of Shigella's mammalian host, and the regulon is repressed at lower temperatures. Virulence gene expression is regulated in both a positive and a negative fashion by several plasmid-encoded activators and at least one chromosomally encoded repressor. The use of a variety of molecular tools including gene fusions, cloning, complementation, DNA sequencing and mRNA analysis, has provided a more complete understanding of how various, unlinked genetic loci contribute in a co-ordinated fashion to the pathogenic phenotype expressed by Shigella.
Mol Biol Med 1989 Oct
PMID:Regulation of virulence genes in Shigella. 269 59

PaeI, a new restriction endonuclease from Pseudomonas aeruginosa clinical strain was isolated and characterized. It recognizes and cleaves the sequence 5'-GCATG reduced C-3' generating DNA fragments with 3'-tetranucleotide sticky ends. DNAs of pBR322, SV40 and bacteriophage lambda have one, two and six PaeI recognition sites, respectively. Seventy-two strains of Pseudomonas, Clostridium, Escherichia coli, Shigella, Proteus and Saccharomyces were screened for the presence of site-specific endonucleases. Here we describe the PaeI restriction enzyme found in Pseudomonas aeruginosa; other data will be published elsewhere. Earlier Hinkle and Miller isolated from P. aeruginosa a PaeR7 restriction endonuclease recognizing and cleaving a sequence 5'-C reduced TCGAG-3' (1). Sequence analysis of DNAs cleaved by PaeI shows that the enzyme is the isoschizomer of SphI (2).
Mol Biol Rep 1985 Apr
PMID:A site-specific endonuclease from Pseudomonas aeruginosa. 299 50

Because bifunctional enzymes are distinctive and highly conserved products of relatively infrequent gene-fusion events, they are particularly useful markers to identify clusters of organisms at different hierarchical levels of a phylogenetic tree. Within the subdivision of gram-negative bacteria known as superfamily B, there are two distinctive types of tyrosine-pathway dehydrogenases: (1) a broad-specificity dehydrogenase (recently termed cyclohexadienyl dehydrogenase [CDH]) that can utilize either prephenate or L-arogenate as alternative substrates and (2) a bifunctional CDH that also posseses chorismate mutase activity. (T-proteins). The bifunctional T-protein, thought to be encoded by fused ancestral genes for chorismate mutase and CDH, was found to be present in enteric bacteria (Escherichia, Shigella, Salmonella, Citrobacter, Klebsiella, Erwinia, Serratia, Morganella, Cedecea, Kluyvera, Hafnia, Edwardsiella, Yersinia, and Proteus) and in Aeromonas and Alteromonas. Outside of the latter "enteric lineage," the T-protein is absent in other major superfamily-B genera, such as Pseudomonas (rRNA homology group I), Xanthomonas, Acinetobacter, and Oceanospirillum. Hence, the T-protein must have evolved after the divergence of the enteric and Oceanospirillum lineages. 3-Deoxy-D-arabino-heptulosonate 7-phosphate synthase-phe, an early-pathway isozyme sensitive to feedback inhibition by L-phenylalanine, has been found in each member of the enteric lineage examined. The absence of both the T-protein and DAHP synthase-phe elsewhere in superfamily B indicates the emergence of these character states at approximately the same evolutionary time.
Mol Biol Evol 1988 May
PMID:The phylogenetic origin of the bifunctional tyrosine-pathway protein in the enteric lineage of bacteria. 338 29

Topology of the products of the genes 34, 35, 36 and 37 of the bacteriophage T4D long tail fibers were determined with the aid of monospecific antibodies. The antibodies against gene product 34 were the only to interact with the proximal part of long tail fibers, but the distal part bound the antibodies against 35, 36 and 37. Product of the gene 35 is located at the joint-site with the distal part and binds the distance not more than 75 A long. Gene product 36 is located between these of 35 and 37 and occupy the region about 150 A. The capability of the antibodies obtained against the above-mentioned proteins were tested ot bind with long tail fibers diagnostic phages DDVIh+ and DDVIh Shigella disentheriae. We could'nt mark any difference in binding of the antibodies against gene 34, 35 and 36 product with DDVI phages and T4D. The distal part of the fibers of DDVIh bound the antibodies against product of gene 37 as T4D. Nevertheless DDVIh+ possesses only few antigenic sites relative to product of gene 37 of T4. The changes in the distal part of long tail fibers of h-strain DDVI may lead to the broadening of the host specifity of this virus.
Mol Biol (Mosk)
PMID:[Topology of the structural proteins of long tail fibers of phages T4D, DDVIh+ and DDVIh]. 635 21


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