Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A Haemophilus influenzae gene encoding a protein with high homology to ArcB receptor protein from Escherichia coli has been cloned. An error in the previously reported sequence of this gene has been found, thus increasing its open reading frame. The cloned gene comprising the entire open reading frame restores oxygen-dependent regulation of succinate dehydrogenase in an ArcB-deficient E. coli strain. Thus, this gene is a functional analog of ArcB from E. coli. By screening partially sequenced bacterial genomes using the BLAST program, proteins with high homology to ArcB protein from E. coli were found in Salmonella typhi, Yersinia pestis, Vibrio cholerae, and Pasteurella multocida. Comparison of these proteins with ArcB protein from E. coli and H. influenzae revealed conserved amino acid regions. Transmembrane helix II was shown to be highly homologous in all the ArcB-type proteins. The involvement of this region in ArcB-mediated oxygen-dependent regulation is suggested.
 ...
PMID:Analysis of HI0220 protein from Haemophilus influenzae, a novel structural and functional analog of ArcB protein from Escherichia coli. 1111 51

The comparative approach is a powerful tool for the analysis of gene regulation in bacterial genomes. It can be applied to the analysis of regulons that have been studied experimentally as well as that of regulons for which no known regulatory sites are available. It is assumed that the set of co-regulated genes and the regulatory signal itself are conserved in related genomes. Here, we use genomic comparisons to study the regulation of transport and utilization systems for sugar acids in gamma purple bacteria Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, Yersinia pestis, Erwinia chrysanthemi, Haemophilus influenzae and Vibrio cholerae. The variability of the operon structure and the location of the operator sites for the main transcription factors are demonstrated. The common metabolic map is combined with known and predicted regulatory interactions. It includes all known and predicted members of the GntR, UxuR/ExuR, KdgR, UidR and IdnR regulons. Moreover, most members of these regulons seem to be under catabolite repression mediated by CRP. The candidate UxuR/ExuR signal is proposed, the KdgR consensus is extended, and new operators for all transcription factors are identified in all studied genomes. Two new members of the KdgR regulon, a hypothetical ATP-dependent transport system OgtABCD and YjgK protein with unknown function, are detected. The former is likely to be the transport system for the products of pectin degradation, oligogalacturonides.
 ...
PMID:Transcriptional regulation of transport and utilization systems for hexuronides, hexuronates and hexonates in gamma purple bacteria. 1111 4

In Yersinia pestis, the causative agent of plague, two inorganic iron transport systems have been partially characterized. The yersiniabactin (Ybt) system is a siderophore-dependent transport system required for full virulence. Yfe is an ABC transport system that accumulates both iron and manganese. We have identified and cloned a Y. pestis yfuABC operon. The YfuABC system is a member of the cluster of bacterial ABC iron transporters that include Sfu of Serratia, Hit of Haemophilus, and Yfu of Yersinia enterocolitica. The Y. pestis KIM6+ system is most homologous to that in Y. enterocolitica, showing identities of 84% for YfuA (periplasmic binding protein), 87% for YfuB (inner membrane permease), and 75% for YfuC (ATP hydrolase). We constructed a yfuABC promoter-lacZ fusion to examine regulation of transcription. This promoter contains a potential Fur binding sequence and is iron and Fur regulated. Significant expression from the yfuABC promoter occurred during iron-deficient growth conditions. In vitro transcription and translation of a recombinant plasmid encoding yfuABC indicates that YfuABC proteins are expressed. Escherichia coli 1017 (an enterobactin-deficient mutant) carrying this plasmid was able to grow in an iron-restrictive complex medium. We constructed a deletion encompassing the yfuABC promoter and most of yfuA. This mutation was introduced into strains with mutations in Ybt, Yfe, or both systems to examine the role of Yfu in iron acquisition in Y. pestis. Growth of the yfu mutants in a deferrated, defined medium (PMH2) at 26 and 37 degrees C failed to identify a growth or iron transport defect due to the yfu mutation. Fifty percent lethal dose studies in mice did not demonstrate a role for the Yfu system in mammalian virulence.
 ...
PMID:Characterization of the Yersinia pestis Yfu ABC inorganic iron transport system. 1129 95

Computational comparative techniques were applied to analysis of the aromatic amino acid regulons in gamma-proteobacteria. This resulted in characterization of the TrpR and TyrR regulons in the genomes of Yersinia pestis, Haemophilus influenzae, Vibrio cholerae and other bacteria and identification of new members of the PhhR regulon in the genome of Pseudomonas aeruginosa. Candidate attenuators were constructed for all studied genomes, including the trpBA operon of the very distantly related bacterium Chlamidia trachomatis. The pheA attenuator of Y. pestis is an integration site for the insertion element IS-200. It was shown that the triplication of the DAHP-synthase genes occurred prior to the divergence of families Enterobacteriaceae, Vibrionaceae and Alteromonadaceae. The candidate allosteric control site of the DAHP-syntheases was identified. This site is deteriorated in AroH of Buchnera sp. APS. The known DAHP-synthase of Bordetella pertussis is likely to be feedback-inhibited by phenylalanine, and the DAHP-synthase of Corynebacterium glutamicum could be inhibited by tyrosine. Overall, the most extensive regulation was observed in Escherichia coli, whereas the regulation in other genomes seems to be less developed. At the extreme, the tryptophan production in the aphid endosymbiont Buchnera sp. APS is free from transcriptional, attenuation, and allosteric control.
 ...
PMID:Regulation of aromatic amino acid biosynthesis in gamma-proteobacteria. 1154 72

A putative LysR-type transcriptional activator, Hre20, was identified previously in an in vivo expression technology screen designed to identify factors which are expressed early during infection by Yersinia enterocolitica (G. M. Young and V. L. Miller, Mol. Microbiol. 25:319-328, 1997). An insertion in hre20, now designated rscR, resulted in increased splenic dissemination of bacteria during infection in a BALB/c mouse model. A nonpolar mutation was generated in rscR, and examination of this strain in the BALB/c mouse model demonstrated that the mutation in rscR was responsible for the increased dissemination to the spleen that was seen in the original experiments. RscR is homologous to the LysR family of transcriptional regulators; thus, a screen was undertaken to identify genes regulated by RscR. A strain containing an insertion in the chromosomal rscR gene and carrying rscR on a plasmid under the control of the inducible araBAD promoter was mutagenized with an mTn5Km-2 transposon containing a promoterless lacZY. Eighteen insertions were identified which appeared to respond to levels of RscR, and these were classified into four allelic groups based on Southern blot hybridization analysis. Representative members were sequenced from three allelic groups. Sequencing revealed insertions in an ORF with no known homologues, a homologue of OmpF of Serratia marcescens, and a locus (designated rscBAC) with similarity to the hmwABC locus of Haemophilus influenzae. The hmwABC locus promotes adherence of H. influenzae to host cells (S. J. Barenkamp and J. W. St. Geme III, Infect. Immun. 62:3320-3328, 1994; J. W. St. Geme III, S. Falkow, and S. J. Barenkamp, Proc. Natl. Acad. Sci. USA 90:2875-2879, 1993). A strain containing a deletion mutant of rscA, the hmwA homologue, exhibits increased splenic dissemination of bacteria during infection in a BALB/c mouse model, similar to the rscR mutant. This suggests that the phenotype of an rscR mutant is due to the loss of RscA.
 ...
PMID:Identification of a locus involved in systemic dissemination of Yersinia enterocolitica. 1155 61

Sickle cell anaemia (SCA) predisposes a child to infections for various reasons, including increased bone marrow turnover, poor perfusion and functional asplenia leading to decreased opsonisation of polysaccharide encapsulated organisms. Bacteria and viruses that most frequently cause serious infections in children with sickle cell disease are Streptococcus pneumoniae, Haemophilus influenzae type b, Salmonella spp., Escherichia coli, Staphylococcus aureus, Mycoplasma pneumoniae, Chlamydia pneumoniae, parvovirus B19 and hepatitis A, B and C viruses. Penicillin prophylaxis has decreased the incidence of infection-related morbidity and mortality significantly in children with SCA. Children <3 years of age are administered oral penicillin 125mg twice daily, and the dose is increased to 250mg twice daily for the >3 to 5 year age group. Adherence to the penicillin prophylactic regimen is recommended for children with SCA who are >5 years of age. For children with SCA who have recurrent invasive pneumococcal infections, an effort is made to keep the child on penicillin prophylaxis indefinitely. The administration of various childhood vaccines has also made an appreciable impact on the overall morbidity and mortality associated with infection in children with SCA. The administration of the heptavalent conjugate pneumococcal vaccine (PCV7) has provided control of invasive pneumococcal infections, and the prophylactic use of the H. influenzae type b conjugate vaccine has reduced the incidence of septicaemia and meningitis caused by this organism. Other vaccines used prophylactically in children with SCA include hepatitis A and B, and vaccines against influenza and varicella viruses. The immediate administration of intravenous antibacterials, after appropriate blood and urine cultures, is of great importance in the treatment of the febrile child with SCA. Ceftriaxone and cefotaxime have been recommended for the treatment of septic episodes in SCA associated with S. pneumoniae, Haemophilus and Salmonella spp. Infection with Yersinia enterocolitica may be treated with cefotaxime or an aminoglycoside. The prevalence of Helicobacter pylori infection in SCA is unknown. Effective therapies include metronidazole, tetracycline or amoxicillin. Parvovirus infections require supportive care and specific antiviral therapy is not indicated. The judicious use of antimicrobials is encouraged in view of the worldwide emergence of multidrug-resistant strains. The long term sequelae associated with infections in children with SCA can be decreased with the implementation of immunisation programmes and effective and prompt treatment with appropriate antibacterials.
 ...
PMID:Prevention and management of infection in children with sickle cell anaemia. 1173 65

Invasive bacterial pathogens intervene at various stages and by various mechanisms with the mammalian plasminogen/plasmin system. A vast number of pathogens express plasmin(ogen) receptors that immobilize plasmin(ogen) on the bacterial surface, an event that enhances activation of plasminogen by mammalian plasminogen activators. Bacteria also influence secretion of plasminogen activators and their inhibitors from mammalian cells. The prokaryotic plasminogen activators streptokinase and staphylokinase form a complex with plasmin(ogen) and thus enhance plasminogen activation. The Pla surface protease of Yersinia pestis resembles mammalian activators in function and converts plasminogen to plasmin by limited proteolysis. In essence, plasminogen receptors and activators turn bacteria into proteolytic organisms using a host-derived system. In Gram-negative bacteria, the filamentous surface appendages fimbriae and flagella form a major group of plasminogen receptors. In Gram-positive bacteria, surface-bound enzyme molecules as well as M-protein-related structures have been identified as plasminogen receptors, the former receptor type also occurs on mammalian cells. Plasmin is a broad-spectrum serine protease that degrades fibrin and noncollagenous proteins of extracellular matrices and activates latent procollagenases. Consequently, plasmin generated on or activated by Haemophilus influenzae, Salmonella typhimurium, Streptococcus pneumoniae, Y. pestis, and Borrelia burgdorferi has been shown to degrade mammalian extracellular matrices. In a few instances plasminogen activation has been shown to enhance bacterial metastasis in vitro through reconstituted basement membrane or epithelial cell monolayers. In vivo evidence for a role of plasminogen activation in pathogenesis is limited to Y. pestis, Borrelia, and group A streptococci. Bacterial proteases may also directly activate latent procollagenases or inactivate protease inhibitors of human plasma, and thus contribute to tissue damage and bacterial spread across tissue barriers.
 ...
PMID:Bacterial plasminogen activators and receptors. 1174 90

One of the main trends in the prokaryote genomics is the comparative analysis of metabolic pathways. This method can be used for the analysis of experimentally studied systems of co-regulated genes, as well as genes with unknown regulatory signals. In this study we apply the comparative analysis of regulatory signals to the genes of the enzymes for fatty acid metabolism from Escherichia coli, Haemophilus influenzae, Vibrio cholerae, Yersinia pestis. Transcription of these genes is regulated by the FadR protein. We describe the FadR regulation of the long-chain fatty acid oxidation and partially that of the fatty acid biosynthesis. We also demonstrate that the gene yafH encoding acyl-CoA dehydrogenase is identical to the gene fadE, previously identified by genetic techniques.
 ...
PMID:[Study on regulation of long-chain fatty acid metabolism with the use of computer analysis of complete bacterial genomes]. 1177 Nov 24

A prospective study was carried out on 210 cases of children under 10 years of age with fever. Cases of gastroenteritis, respiratory tract infections, and suspected sepsis in children seen or admitted to the pediatric hospital were studied. Clinical and microbiological data were recorded in a questionnaire or obtained from patient medical records. Most of the children with septicemia (71.3 per cent) were less than 1 year old. Focal source of bacteremia was gastroenteritis (40.4 per cent), pneumonia or bronchopneumonia (20 per cent), meningitis (7.4 per cent), and urinary tract infections (7.4 per cent). The predominant pathogens isolated from blood or stool specimens were gram-positive bacteria (53.3 per cent), mainly Streptococcus pneumoniae and coagulase-negative Staphylococcus spp. The gram-negative bacteria (45.6 per cent) were mainly Escherichia coli, Klebsiella pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and Yersinia spp. One case of Candida albicans (1.1 per cent) was reported. Pasteurella pneumotropica was reported in two cases for the first time. The mortality rate was 4 per cent, mostly from septicemia cases. Long duration of hospitalization (> 10 days) and parenteral feeding were identified as risk factors. Resistance of the isolated pathogens to several commonly used antibiotics was observed. Empirical treatment with antibiotics is recommended only in life-threatening cases.
 ...
PMID:Bacteremia in children: etiologic agents, focal sites, and risk factors. 1182 4

The polymerase chain reaction (PCR) offers a sensitive and specific way of detecting microbial DNA in clinical samples. The aims of the present study were to develop an assay, based on a single-tube, nested PCR, for identifying Brucella in samples of human blood and then to explore the use of this test in diagnosis. The primers chosen were derived from IS711, the insertion sequence gene found in all species of Brucella. The assay amplified a 52-bp final product which was detected colorimetrically. The PCR was sensitive and specific, giving positive reactions with 14 strains of Brucella from five species. The lower limit of detection in vitro was 30 organisms. There were no false-positive reactions either with a range of bacteria known to evoke serological cross-reactions with Brucella (Vibrio cholerae, Yersinia enterocolitica, Serratia marcescens, Haemophilus influenzae, Pseudomonas aeruginosa and Escherichia coli K12) or with organisms producing similar clinical syndromes (Mycobacterium tuberculosis and Salmonella typhi). The results of a preliminary field trial of the assay in Kuwait indicate that the assay may be a valuable technique in the diagnosis of human brucellosis, meriting further study with larger numbers of cases. All 28 subjects with brucellosis (diagnosed on the basis of typical clinical features and confirmed by positive serology and, in three cases, by positive blood cultures) were PCR-positive whereas 28 healthy controls and 28 patients with febrile illness attributable to infections other than brucellosis were PCR-negative.
 ...
PMID:Single-tube, nested PCR for the diagnosis of human brucellosis in Kuwait. 1217 21


<< Previous 1 2 3 4 5 6 7 8 9 Next >>