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

Several properties of Haemophilus influenzae outer membrane proteins were analyzed to define related proteins in various isolates. H. influenzae type b 760705 had six major outer membrane proteins with the following characteristics. Protein a (Mr, 47,000) demonstrated heat modifiability in sodium dodecyl sulfate; its apparent molecular weight was 34,000 at temperatures below 60 degrees C. This protein was extracted from cell envelopes by using Triton X-100-10 mM MgCl2; in cell envelope preparations, the protein was degraded by trypsin. Proteins b (Mr, 41,000) and c (Mr, 40,000) were insensitive to trypsin degradation, were not heat modifiable in sodium dodecyl sulfate, and were peptidoglycan associated in 0.5% Triton X-100-0.2% sodium dodecyl sulfate. The amount of protein b was reduced in ultrasonically obtained cell envelopes. Protein d (Mr, 37,000) was heat modifiable in sodium dodecyl sulfate with an Mr of 28,000 at temperatures below 100 degrees C and was degraded by trypsin, leaving a membrane-bound fragment of Mr, 27,000. Both the intact and degraded proteins were immunologically cross-reactive with the heat-modifiable OmpA protein of Escherichia coli K-12. Protein d was absent in LiCl-EDTA extracts of cells. Protein e (Mr, 30,000), invariably present in all H. influenzae strains tested, was insensitive to trypsin and absent in LiCl-EDTA extracts of cells. Protein k (Mr, 58,000) was extracted from cell envelopes with 2% Triton X-100-10 mM MgCl2 and, in cell envelopes, appeared to be sensitive to trypsin degradation. Proteins with similar properties to those of proteins a to k were found in 10 other H. influenzae b strains, reference strains with serotype a, c, d, e, and f capsules, and 18 of 20 nonencapsulated strains. Their relative molecular weights, however, varied.
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PMID:Characteristics of major outer membrane proteins of Haemophilus influenzae. 660 58

The mechanism of non-beta-lactamase-mediated beta-lactam resistance in a clinical isolate of Haemophilus influenzae type b was studied. This clinical isolate showed up to a 32-fold increase in MICs of a wide variety of beta-lactams, including moxalactam and cefotaxime, although no beta-lactamase activity was detected, even after attempted induction. Transformation of broad-spectrum beta-lactam resistance into ampicillin-susceptible H. influenzae RDnov was accomplished. Examination of the outer membrane protein profile of the resistant parent by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of Triton X-100-extracted membranes revealed an unusual major outer membrane protein band at a molecular weight of 45,000. This outer membrane protein profile did not transform with beta-lactam resistance. Permeability differences were noted between the resistant strain and the nonisogenic susceptible strain of H. influenzae, although these penetration differences were not transformed. Comparison of the penicillin-binding protein profile of a resistant transformant with that of a susceptible parent with both whole-membrane preparations and whole-cell labeling, revealed a major reduction in binding affinity to penicillin-binding proteins 3a and 3b (molecular weights, 68,000 and 65,000, respectively). Thus, alteration in penicillin-binding proteins 3a and 3b correlated with the beta-lactam resistance.
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PMID:Mechanism of resistance of an ampicillin-resistant, beta-lactamase-negative clinical isolate of Haemophilus influenzae type b to beta-lactam antibiotics. 661 Nov 36

To examine the role of surface tension lowering substances (STLSs), we measured changes in passive opening pressure (OP) and closing pressure (CP) in eustachian tubes of guinea pigs before and after washing the tubes with various solutions (saline solution, artificial pulmonary surfactant, synthetic phospholipids, and detergent)). The percent decreases in OP and CP in tubes washed with artificial surfactant were significantly higher than those washed with saline solution. Those washed with synthetic phospholipids or detergent (Triton X-100) did not differ from those washed with saline solution. In guinea pigs with experimental otitis media produced by inoculation of formalin-killed Haemophilus influenzae into the middle ear cavity, the percent decreases in OP and CP in tubes washed with artificial pulmonary surfactant were significantly higher than in those washed with saline solution. Artificial pulmonary surfactant was injected into the middle ear cavity of the guinea pigs with otitis media. At 5 days after inoculation, the inflammatory changes of the middle ear were much milder in animals with intratemporal application of artificial pulmonary surfactant than in those with saline application. These results suggest the possible efficacy of treatment with artificial pulmonary surfactant for otitis media.
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PMID:[Role of surface tension lowering substances in the function of normal and diseased eustachian tubes of guinea pigs]. 850 40

We report the purification, molecular cloning, and characterization of a 40-kDa glycerophosphodiester phosphodiesterase homolog from Borrelia hermsii. The 40-kDa protein was solubilized from whole organisms with 0.1% Triton X-100, phase partitioned into the Triton X-114 detergent phase, and purified by fast-performance liquid chromatography (FPLC). The gene encoding the 40-kDa protein was cloned from a B. hermsii chromosomal DNA lambda EXlox expression library and identified by using affinity antibodies generated against the purified native protein. The deduced amino acid sequence included a 20-amino-acid signal peptide encoding a putative leader peptidase II cleavage site, indicating that the 40-kDa protein was a lipoprotein. Based on significant homology (31 to 52% identity) of the 40-kDa protein to glycerophosphodiester phosphodiesterases of Escherichia coli (GlpQ), Bacillus subtilis (GlpQ), and Haemophilus influenzae (Hpd; protein D), we have designated this B. hermsii 40-kDa lipoprotein a glycerophosphodiester phosphodiesterase (Gpd) homolog, the first B. hermsii lipoprotein to have a putative functional assignment. A nonlipidated form of the Gpd homolog was overproduced as a fusion protein in E. coli BL21(DE3)(pLysE) and was used to immunize rabbits to generate specific antiserum. Immunoblot analysis with anti-Gpd serum recognized recombinant H. influenzae protein D, and conversely, antiserum to H. influenzae protein D recognized recombinant B. hermsii Gpd (rGpd), indicating antigenic conservation between these proteins. Antiserum to rGpd also identified native Gpd as a constituent of purified outer membrane vesicles prepared from B. hermsii. Screening of other pathogenic spirochetes with anti-rGpd serum revealed the presence of antigenically related proteins in Borrelia burgdorferi, Treponema pallidum, and Leptospira kirschneri. Further sequence analysis both upstream and downstream of the Gpd homolog showed additional homologs of glycerol metabolism, including a glycerol-3-phosphate transporter (GlpT), a glycerol-3-phosphate dehydrogenase (GlpD), and a thioredoxin reductase (TrxB).
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PMID:Sequence analysis and characterization of a 40-kilodalton Borrelia hermsii glycerophosphodiester phosphodiesterase homolog. 907 9

Whereas mammalian cells produce PS by a base exchange reaction from preexisting phospholipids, yeast cells synthesize PS from CDP-diacylglycerol and serine by the PS synthase reaction. Yeast PS synthase was purified to homogeneity and shown to have a molecular mass of 23 kDa. The activity is dependent on either Mg2+ or Mn2+ and Triton X-100. The enzyme specifically transfers the phosphatidyl group from CDP-diacylglycerol or dCDP-diacylglycerol to L-serine, but not to threonine, cysteine and ethanolamine. The PSS/CHO1 gene encoding the enzyme was cloned by the complementation of the choline auxotrophic pss/cho1 mutant. The deduced protein comprises 279 amino acids with a calculated molecular mass of 30,804. The primary translate undergoes proteolytic processing to the enzymatically more active 23-kDa enzyme. The deduced amino acid sequence contains several putative membrane-spanning regions and resembles that of the Bacillus subtilis enzyme, but not those of the E. coli and Haemophilus influenzae enzymes. The sequence also contains the local, conserved region found in enzymes catalyzing the transfer of the phosphoalcohol moiety from CDP-alcohol, such as PI synthase, cholinephosphotransferase and phosphatidylglycerolphosphate synthase. The activity of PS synthase is maximal in the exponential phase, but decreases when cells enter the stationary phase. The enzyme is phosphorylated at a single serine residue by cyclic AMP-dependent protein kinase with a 60-70% decrease in enzymatic activity, but the primary translation product is not phosphorylated. PS synthase is inhibited by CTP, probably due to the chelation of the divalent cations, Mg2+ and Mn2+, and also by sphingoid bases, such as sphinganine and phytosphingosine. Phosphatidate, phosphatidylcholine and phosphatidylinositol are stimulatory, whereas cardiolipin and diacylglycerol are inhibitory. The expression of yeast PS synthase is transcriptionally repressed by myo-inositol and choline in a coordinate manner with other phospholipid-synthesizing enzymes. The upstream regulatory region of the PSS/CHO1 gene responsible for the myo-inositol-choline regulation was identified. An octameric sequence, CATRTGAA (R = A or G), plays an important role in the conferral of the myo-inositol-choline transcriptional regulation.
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PMID:Phosphatidylserine synthase from yeast. 937 Mar 37

The function of the streptococcal cytoplasmic membrane lipoprotein, LppC, was identified with isogenic Streptococcus equisimilis H46A and Escherichia coli JM109 strain pairs differing in whether they contained [H46A and JM109(pLPP2)] or lacked (H46A lppC::pLPP10 and JM109) the functional lppC gene for comparative phosphatase determinations under acidic conditions. lppC-directed acid phosphatase activity was demonstrated zymographically and by specific enzymatic activity assays, with whole cells or cell membrane preparations as enzyme sources. LppC acid phosphatase showed optimum activity at pH 5, and the enzyme activity was unaffected by Triton X-100, L-(+)-tartaric acid, or EDTA. Database searches revealed significant structural homology of LppC to the Streptococcus pyogenes LppA, Flavobacterium meningosepticum OplA, Helicobacter pylori HP1285, and Haemophilus influenzae Hel [e (P4)] proteins. These results suggest a possible function for these proteins and establish a novel function of streptococcal cell membrane lipoproteins.
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PMID:Cytoplasmic membrane lipoprotein LppC of Streptococcus equisimilis functions as an acid phosphatase. 964 12

The prenyltransferase undecaprenyl pyrophosphate synthetase (di-trans,poly-cis-decaprenylcistransferase; EC 2.5.1.31) was purified from the soluble fraction of Escherichia coli by TSK-DEAE, ceramic hydroxyapatite, TSK-ether, Superdex 200, and heparin-Actigel chromatography. The protein was labeled with the photolabile analogue of the farnesyl pyrophosphate analogue (E, E)-[1-3H]-(2-diazo-3-trifluoropropionyloxy)geranyl diphosphate and was detected on a sodium dodecyl sulfate-polyacrylamide gel as a protein with an apparent molecular mass of 29 kDa. This protein band was cut out from the gel, trypsin digested, and subjected to matrix-assisted laser desorption ionization mass spectrometric analysis. Comparison of the experimental data with computer-simulated trypsin digest data for all E. coli proteins yielded a single match with a protein of unassigned function (SWISS-PROT Q47675; YAES_ECOLI). Sequences with strong similarity indicative of homology to this protein were identified in 25 bacterial species, in Saccharomyces cerevisiae, and in Caenorhabditis elegans. The homologous genes (uppS) were cloned from E. coli, Haemophilus influenzae, and Streptococcus pneumoniae, expressed in E. coli as amino-terminal His-tagged fusion proteins, and purified over a Ni2+ affinity column. An untagged version of the E. coli uppS gene was also cloned and expressed, and the protein purified in two chromatographic steps. We were able to detect Upp synthetase activity for all purified enzymes. Further, biochemical characterization revealed no differences between the recombinant untagged E. coli Upp synthetase and the three His-tagged fusion proteins. All enzymes were absolutely Triton X-100 and MgCl2 dependent. With the use of a regulatable gene disruption system, we demonstrated that uppS is essential for growth in S. pneumoniae R6.
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PMID:Use of genomics to identify bacterial undecaprenyl pyrophosphate synthetase: cloning, expression, and characterization of the essential uppS gene. 988 62

UDP-2,3-diacylglucosamine hydrolase is believed to catalyze the fourth step of lipid A biosynthesis in Escherichia coli. This reaction involves pyrophosphate bond hydrolysis of the precursor UDP-2,3-diacylglucosamine to yield 2,3-diacylglucosamine 1-phosphate and UMP. To identify the gene encoding this hydrolase, E. coli lysates generated with individual lambda clones of the ordered Kohara library were assayed for overexpression of the enzyme. The sequence of lambda clone 157[6E7], promoting overproduction of hydrolase activity, was examined for genes encoding hypothetical proteins of unknown function. The amino acid sequence of one such open reading frame, ybbF, is 50.5% identical to a Haemophilus influenzae hypothetical protein and is also conserved in most other Gram-negative organisms, but is absent in Gram-positives. Cell extracts prepared from cells overexpressing ybbF behind the T7lac promoter have approximately 540 times more hydrolase activity than cells with vector alone. YbbF was purified to approximately 60% homogeneity, and its catalytic properties were examined. Enzymatic activity is maximal at pH 8 and is inhibited by 0.01% (or more) Triton X-100. The apparent K(m) for UDP-2,3-diacylglucosamine is 62 microm. YbbF requires a diacylated substrate and does not cleave CDP-diacylglycerol. (31)P NMR studies of the UMP product generated from UDP-2,3-diacylglucosamine in the presence of 40% H(2)180 show that the enzyme attacks the alpha-phosphate group of the UDP moiety. Because ybbF encodes the specific UDP-2,3-diacylglucosamine hydrolase involved in lipid A biosynthesis, it is now designated lpxH.
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PMID:The Escherichia coli gene encoding the UDP-2,3-diacylglucosamine pyrophosphatase of lipid A biosynthesis. 1200 Jul 70

The identification of Brachyspira hyodysenteriae outer membrane proteins (OMPs) that may stimulate immunity to swine dysentery is important for vaccine development. We report here the analysis of a novel locus, blpGFEA, encoding four tandem paralogous proteins of approximately 30 kDa from B. hyodysenteriae. The four proteins share 31-39% sequence identity with lipoproteins from several species of bacterial pathogens, but the locus possesses a unique genetic organization. Using antisera raised to recombinant versions of each of these proteins, only BlpA and BlpE were found to be immunologically cross-reactive with the other proteins encoded by the locus. Northern hybridization indicated that only blpA was expressed under in vitro growth conditions. In addition, convalescent swine serum recognized recombinant BlpA in immunoblotting experiments, demonstrating that it is also expressed during infection. Analysis of the translated sequences of each of the genes revealed atypical spirochetal signal peptidase II recognition sites, and BlpA was shown to be a lipoprotein by incorporation of tritiated palmitic acid. Native BlpA was completely extracted by Triton X-114 (TX-114) and partitioned exclusively into the detergent phase during extraction of whole B. hyodysenteriae cells, implicating it as a component of the brachyspiral outer membrane. Consistent with the transcriptional and immunological data, analysis of the brachyspiral outer membrane proteome also revealed expression of only BlpA. Notably, inactivation of blpA homologs in Haemophilus influenzae and Salmonella enteritidis resulted in attenuation of virulence.
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PMID:Characterization of a locus encoding four paralogous outer membrane lipoproteins of Brachyspira hyodysenteriae. 1270 40

Three strains of nontypeable Haemophilus influenzae namely NTHi-I, NTHi-II and NTHi-III were isolated from the sputum of patients with bronchitis and identified by biochemical, serological and electron microscopy. The polypeptide patterns of isolates were compared and found to have similar sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) polypeptide patterns, although some of the bands were specific in some strains. A similar comparison was made on extracted outer membrane proteins (OMPs) on the above mentioned strains, using Triton X-100 and sodium dodecyle sulphate (SDS). It was found that the polypeptides with molecular weights of 70, 42, 33 and 27 KDa were identified as P1, P2, P4 and P5 respectively. The protein estimation of crude OMPs from the three strains were calculated, and OPM-I prepared from NTHi-I showed the highest amount of protein and was chosen for its immunogenicity in a rat respiratory model. The efficacy of immunization with OMP was determined by enhancement of pulmonary clearance of live bacteria in the rat lung. A significant protective immune response induced by OMP was observed by enhanced respiratory clearance of nontypeable H. influenzae following mucosal immunization.
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PMID:Efficacy of immunization with outer membrane proteins for induction of pulmonary clearance of nontypeable Haemophilus influenzae in a rat respiratory model. 1723 77


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