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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two isogenic mutants of Haemophilus influenzae type b (Hib) strain A2 were prepared by random m-Tn3(Cm) insertions into the 7.4-kb lsg (lipooligosaccharide synthesis genes) region of Hib DNA, which consists of seven complete and one partial open reading frame (orfs). Compared to the parent A2 strain which produces a complex mixture of lipooligosaccharides (LOS), the mutant strains 281.25 and 276.4 produced only a few LOS species. The precise locations of transposon insertions into the lsg loci of these mutants were determined (base 3546 in orf 4 for strain 281.25 and base 4402 in orf 5 for strain 276.4), and the effects of these mutations on LOS biosynthesis and epitope expression were evaluated. When the O-deacylated LOS were analyzed by mass spectrometry, both strains contained major LOS species of M(r) 2601, 2439, and 2277, which consisted of a common heptose trisaccharide core structure [Hep3(PEA)Kdo(P)-lipid A, where Hep is L-glycero-D-manno-heptose, Kdo is 3-deoxy-D-manno-octulosonic acid, and PEA is phosphoethanolamine] and four, three, or two hexoses, respectively. These species represent the smallest components of the wild-type LOS mixture. The major LOS oligosaccharide obtained from the strain 281.25 by mild acid hydrolysis was dephosphorylated and shown by composition analysis, methylation analysis, mass spectrometry, and 2D NMR studies to be a triantennary structure consisting of a heptose trisaccharide core with two glucose disaccharide branches: Hep alpha 1 --> (Glc beta 1 --> 4Glc alpha 1 --> 3) 2Hep alpha 1 --> (Glc beta 1 --> 4Glc beta 1 --> 4)3Hep alpha 1 --> anhydroKdo. Unlike the parent A2 strain, mutant strain 281.25 cannot add galactoses to the branches of this octasaccharide. Strain 276.4 is similarly deficient, except that it can still utilize a minor biosynthetic pathway leading to the addition of sialyl-N-acetyllactosamine.
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PMID:Characterization of two transposon mutants from Haemophilus influenzae type b with altered lipooligosaccharide biosynthesis. 863 56

Treponema pallidum, the agent of syphilis, cannot be continuously cultivated in vitro. To identify treponemal genes encoding exported proteins, we performed TnphoA mutagenesis of a T. pallidum genomic DNA library in Escherichia coli. Clone 6D2 was chosen for further study based on partial nucleotide sequence obtained from p6D2 containing a TnphoA insertion. A complete open reading frame (orf1) and a truncated orf (orf2) were identified in the treponemal DNA of p6D2. Orf1 encodes a hydrophobic protein of 531 amino acids with a calculated M(r) of 57,882 Da. The deduced amino acid sequence of Orf1 has homology to the MglC proteins of E. coli, Haemophilus influenzae, and Salmonella typhimurium. T. pallidum Orf1 (MglC) contains a conserved motif that is found in integral cytoplasmic membrane proteins of ATP-binding cassette (ABC) transport systems. T. pallidum orf2 encodes a protein of 496 amino acids with a calculated M(r) of 55,547 Da. The deduced amino acid sequence of Orf2 has homology to the MglA proteins of S. typhimurium, E. coli, H. influenzae, and Mycoplasma genitalium. Orf2 (MglA) contains two consensus ATP-binding motifs. T. pallidum mglA and mglC are located downstream of mglB, consistent with the gene order of previously identified mgl operons. The putative T. pallidum mgl operon encodes the first high-affinity ABC transport system identified in this spirochete.
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PMID:Identification and sequences of the Treponema pallidum mglA and mglC genes. 898 65

Comparison of the nucleotide sequences of the left arms of two Haemophilus influenzae phages, S2 and HP1 is presented. They exhibit a characteristic mosaic pattern of homologous and non-homologous regions. The homology extends over the attP site and int, orf 5 to 9, rep and the 3' part of cI genes. Two major non-homologous regions were detected. One is found between the int and cI genes; the other spans the region of promoters and the cox gene. Variations in the region of the promotors which is involved in the choice between a lysogenic and a lytic pathway and some divergences in the cI coding sequences are probably responsible for the observed immunity differences between the two phages. Distinctions in the distribution of consensus sequences for an integration host factor (IHF) and integrase-binding sites and promoters are described. These data offer an explanation of the relationship between three types of S2/HP1 phages. It allows in turn a final settlement of the nomenclature variation in the literature. The results presented, which are similar to those obtained for other phage groups, suggest that the mosaic structure of phage genomes is a normal outcome of phage divergence.
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PMID:The relationship between HP1 and S2 bacteriophages of Haemophilus influenzae. 932 51

We report the construction of physical and genetic maps of the chromosome of Leptospira interrogans serovar icterohaemorrhagiae strain Ictero No.1 using pulsed-field gel electrophoresis of DNA fragments generated by digestion with enzymes SrfI, AscI, FseI, and NotI and using reciprocal hybridization. We also sequenced the 19-kilobase (kb) DNA segment including the one gene for 5S rRNA (rrf) of pathogenic Leptospira. The size of the chromosome of the strain Ictero No.1 was estimated to be 4673kb and was found to be similar to those of the chromosomes of the leptospira strains Verdun (serovar icterohaemorrhagiae) and RZ11 (serovar pomona). The strains Verdun and RZ11 carry a small 350-kb replicon (minichromosome), and the strain Ictero No.1 also contained the same kind of molecule together with the chromosome. The physical maps of the strains Ictero No.1 and Verdun were almost identical, as were the locations of the selected genes, except for the location of one of the 16S rRNA genes. Overall, the genetic organization appeared to be conserved within the serovar icterohaemorrhagiae strains. In the sequenced region, we identified 10 putative ORFs and one rrf sequence, and the transcription orientations were all the same. A homology search for the products deduced from the sequenced data revealed that the orf H exhibited high similarity to malic acid enzyme of Haemophilus influenzae and fumarate hydratase of Escherichia coli (orf J). The rest of the putative products encoded by ORFs in the sequenced region showed little similarity with the proteins contained in the databases and were considered to be unknown proteins.
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PMID:Physical and genetic maps of the Leptospira interrogans serovar icterohaemorrhagiae strain Ictero no.1 chromosome and sequencing of a 19-kb region of the genome containing the 5S rRNA gene. 966 70

Members of the bacterial families Haemophilus and Neisseria, important human pathogens that commonly colonize the nasopharynx, are naturally competent for DNA uptake from their environment. In each genus this process is discriminant in favor of its own and against foreign DNA through sequence specificity of DNA receptors. The Haemophilus DNA uptake apparatus binds a 29-bp oligonucleotide domain containing a highly conserved 9-bp core sequence, whereas the neisserial apparatus binds a 10-bp motif. Each motif ("uptake sequence", US) is highly over-represented in the chromosome of the corresponding genus, particularly concentrated with core sequences in inverted pairs forming gene terminators. Two Haemophilus core USs were unexpectedly found forming the terminator of sodC in Neisseria meningitidis (meningococcus), and sequence analysis strongly suggests that this virulence gene, located next to IS1106, arose through horizontal transfer from Haemophilus. By using USs as search strings in a computer-based analysis of genome sequence, it was established that while USs of the "wrong" genus do not occur commonly in Neisseria or Haemophilus, where they do they are highly likely to flag domains of chromosomal DNA that have been transferred from Haemophilus. Three independent domains of Haemophilus-like DNA were found in the meningococcal chromosome, associated respectively with the virulence gene sodC, the bio gene cluster, and an unidentified orf. This report identifies intergenerically transferred DNA and its source in bacteria, and further identifies transformation with heterologous chromosomal DNA as a way of establishing potentially important chromosomal mosaicism in these pathogenic bacteria.
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PMID:Natural genetic exchange between Haemophilus and Neisseria: intergeneric transfer of chromosomal genes between major human pathogens. 977 Apr 95

Bacteriophage SfV is a temperate serotype-converting phage of Shigella flexneri. SfV encodes the factors involved in type V O-antigen modification, and the serotype conversion and integration-excision modules of the phage have been isolated and characterized. We now report on the complete sequence of the SfV genome (37,074 bp). A total of 53 open reading frames were predicted from the nucleotide sequence, and analysis of the corresponding proteins was used to construct a functional map. The general organization of the genes in the SfV genome is similar to that of bacteriophage lambda, and numerous features of the sequence are described. The superinfection immunity system of SfV includes a lambda-like repression system and a P4-like transcription termination mechanism. Sequence analysis also suggests that SfV encodes multiple DNA methylases, and experiments confirmed that orf-41 encodes a Dam methylase. Studies conducted to determine if the phage-encoded methylase confers host DNA methylation showed that the two S. flexneri strains analyzed encode their own Dam methylase. Restriction mapping and sequence analysis revealed that the phage genome has cos sites at the termini. The tail assembly and structural genes of SfV show homology to those of phage Mu and Mu-like prophages in the genome of Escherichia coli O157:H7 and Haemophilus influenzae. Significant homology (30% of the genome in total) between sections of the early, regulatory, and structural regions of the SfV genome and the e14 and KpLE1 prophages in the E. coli K-12 genome were noted, suggesting that these three phages have common evolutionary origins.
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PMID:Complete genomic sequence of SfV, a serotype-converting temperate bacteriophage of Shigella flexneri. 1188 6

Objective of the present paper is to review microbial diseases of the genital system of male small ruminants. The paper reviews the infections and the diseases by taking an organ approach within the genital system, whilst relevant health management actions are also discussed. Diseases of the genital organs of male small ruminants include orchitis, of bacterial or viral aetiology, epididymitis, primarily caused by Brucella ovis, by other bacteria as well (e.g., Actinobacillus seminis, Haemophilus somni), infections of the accessory glands, orf, other infections of the penis or prepuce and infections of the scrotum. The health management of rams/bucks include the appropriate diagnostic investigations, the relevant therapeutic approaches and, finally, the preventive measures.
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PMID:Microbial diseases of the genital system of rams or bucks. 2620 19