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)

Covalently closed-circular, superhelical DNAs, including viral DNAs, bacterial plasmid DNAs, and bacteriophage replicative-form DNA, were treated with a small amount of Haemophilus gallinarum DNA-relaxing enzyme to generate incompletely relaxed DNA molecules. Each sample consisted of a set of closed-circular DNA molecules differing by one turn in their number of superhelical turns. The DNA samples were analyzed by agarose gel electrophoresis under conditions such that the electrophoretic mobility was a function of the number of turns. The numbers of superhelical turns (at 37 degrees C in 20 mM Tris-HCl (pH 7.5)-5 mM MgCl2) in the DNAs of pSC101 (5.8 megadaltons), Colicin E1 (4.2 megadaltons), pMR4 (4.0 megadaltons; recombinant between pBR322 and lambda DNA fragment), phi X174 replicative-form (RF) I, Simian virus 40 (SV40), and polyoma virus (3.4--3.6 megadaltons each), and lambda dv021 (2.05 megadaltons) were estimated to be 36, 27, 23--24, 20--21, 20--21, 20--21, and 11--13, respectively. It appears that the number of superhelical turns is mainly a function of the molecular weight of the DNA, at least in the substrates tested here.
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PMID:The use of Haemophilus gallinarum DNA-relaxing enzyme to investigate the relationship between the number of superhelical turns and the molecular weight in a negatively twisted DNA. 22

Purified lipopolysaccharide (LPS) from Haemophilus influenzae type b (Hib) was examined for its capacity to interact with human hemolytic complement, generate conversion products of C3, C4, and factor B, stimulate C5a activity, and affect human neutrophil chemiluminescence and phagocytosis. Salmonella typhimurium LPS and Salmonella minnesota Rb LPS (R345 mutant) were examined for comparison. Incubation of Hib LPS with human serum deficient in gamma-globulin or with normal human serum containing 10 mM EGTA and 7 mM MgCl2 resulted in some depletion of hemolytic complement and conversion of C3 to degradation products (determined by inhibition of passive hemolysis and electrophoresis/immunofixation, respectively), indicating that complement activation occurred by the alternative pathway. Complement activation by Hib LPS and S. minnesota Rb LPS was similar, but significantly less effective than by S. typhimurium LPS (p less than 0.01). Solubilized Hib lipid A, but not LPS, induced conversion products of C4 in hypogammaglobulinemic serum, indicating activation of the classical pathway. Similar levels of C5a activity were generated by incubation of Hib LPS and S. typhimurium LPS in hypogammaglobulinemic serum, as determined by neutrophil shape change and neutrophil aggregation. Hib LPS directly stimulated neutrophil chemiluminescence, whereas S. typhimurium LPS had little effect. Phagocytosis of radiolabeled, opsonized Hib by neutrophils was diminished by S. minnesota Rb LPS, Hib LPS, or solubilized Hib lipid A (p less than 0.001), but was slightly increased by S. typhimurium LPS. Neither the oligosaccharide of Hib LPS or Hib capsular polysaccharide was capable of interacting with complement or altering neutrophil chemiluminescence or phagocytosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of Haemophilus influenzae type b lipopolysaccharide on complement activation and polymorphonuclear leukocyte function. 332 33

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

An evaluation was made of the role of the outer membrane of Haemophilus influenzae type b as a permeability barrier against beta-lactam antibiotics. Sonic extracts of H. influenzae containing beta-lactamase were assayed for the rates of hydrolysis of benzylpenicillin, ampicillin, cloxacillin, cephacetrile, cefazolin, cefamandole, cephalothin, cephaloridine, cephaloglycin, and cefaclor. Benzylpenicillin was hydrolyzed most rapidly, whereas cephacetrile, cephaloridine, and cephaloglycin were the poorest substrates for the beta-lactamase. The hydrolysis of these ten beta-lactams by intact cells was also determined; it was necessary to stabilize the cells with MgCl2 to prevent lysis and thereby to maintain the beta-lactamase in the periplasm. Calculations were made of the concentration of the antibiotics which had accumulated in the periplasm. The transmembrane permeability coefficient, C, was determined for the ten beta-lactam antibiotics. All of the compounds tested were able to diffuse across the outer membrane of H. influenzae type b very efficiently. The values of the permeability coefficient were compared with the partition coefficients of the antibiotics in a two-phase isobutanol/water mixture. For a ten-fold increase in hydrophobicity, there was a ten-fold decrease in the permeability coefficient. The outer membrane of haemophilus was not an effective barrier against the penetration of penicillins or cephalosporins. The activity of these compounds could be attributed either to their low hydrolysis by beta-lactamase or to the high affinity of binding to their sensitive targets.
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PMID:The permeability barrier of Haemophilus influenzae type b against beta-lactam antibiotics. 660 14

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