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)

Five strains of Haemophilus pleuropneumoniae, out of eight strains tested, produced extracellular haemolysin(s) when grown in liquid culture in the presence, but not in the absence, of RNA. The haemolysin produced by the neotype strain was unstable, heat labile, and sensitive to degradation by pronase, trypsin, and chymotrypsin; moreover, trypan blue treated haemolysin preparations were less effective at causing erythrocyte lysis than were untreated preparations. Following growth in the absence of RNA, washed suspensions of the neotype strain produced extracellular haemolysin when incubated in the presence of RNA, glucose, and casein acid hydrolysate; extracellular haemolysin could not be detected if the incubation mixture contained chloramphenicol. The haemolysin produced by washed bacterial suspensions was similar to that produced by growing cultures in that it was unstable, heat labile, and sensitive to inactivation by the same complement of enzymes. Erythrocyte lysis induced by either haemolysin preparation was preceded by a prelytic phase, the duration of which was dependent upon haemolysin concentration and the initial temperature of the haemolysin--erythrocyte mixture. It is concluded that the haemolysin(s) produced by the neotype strain of H. pleuropneumoniae is distinct from, but closely related to both streptolysin S and the haemolysin produced by Treponema hyodysenteriae.
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PMID:Production of RNA-dependent haemolysin by Haemophilus pleuropneumoniae. 240 20

Differences in the major outer membrane protein b,c (molecular weight, 39,000 to 41,000) of related Haemophilus influenzae strains isolated from the sputum of patients with chronic obstructive pulmonary disease were analyzed biochemically and immunologically. Protein b,c was isolated from a total of six related H. influenzae strains from two chronic obstructive pulmonary disease patients. After CNBr digestion of the proteins, the differences in size appeared in the larger of the two fragments. Trypsin and chymotrypsin digests of proteins from related H. influenzae strains showed that proteins differed by only a few peptides or were very similar, in contrast to the peptide maps of proteins from nonrelated strains. Peptide analysis of b,c proteins from related H. influenzae strains by high-performance liquid chromatography after Staphylococcus aureus V8 protease digestion and amino acid analysis of corresponding fractions revealed highly comparable patterns, indicating only minor differences in the amino acid sequences of these proteins. Immunization of rabbits with intact bacteria of four related H. influenzae strains resulted in a strong anti-protein b,c antibody response in all animals. In three of four rabbits, antibodies specific for the b,c protein of the strain used for immunization were elicited, indicating that the changed proteins contained specific immunodominant epitopes. Anti-protein b,c antibodies promoted strain-specific, complement-dependent, bactericidal activity. From these results, we conclude that H. influenzae shows antigenic drift in immunodominant epitopes, caused by small changes in amino acid composition of the b,c protein. Antibodies to these epitopes promote complement-dependent bactericidal activity.
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PMID:Antigenic drift of Haemophilus influenzae in patients with chronic obstructive pulmonary disease. 278 92

Iron-saturated human transferrin was digested with either chymotrypsin or trypsin to produce C-lobe and N-lobe protein fragments. Individual protein fragments were purified by a combination of gel filtration and Concanavalin A affinity chromatographic procedures. The C-lobe and N-lobe fragments of human transferrin were then used in binding assays to assess their ability in binding to the bacterial transferrin receptors. Competitive binding assays demonstrated that the C-lobe fragment of human transferrin binds as well as intact human transferrin to bacterial transferrin receptors from Neisseria meningitidis, Neisseria gonorrhoeae and Haemophilus influenzae. Using isogenic mutants of N. meningitidis deficient in either of the transferrin-binding proteins (Tbps), we demonstrated that both transferrin-binding proteins were able to bind to the C-lobe fragment of human transferrin.
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PMID:The region of human transferrin involved in binding to bacterial transferrin receptors is localized in the C-lobe. 836 58

Cystic fibrosis (CF) is a severe disorder, whose main characteristics are, in addition to congenital absence of the vas deferens (CAVD), progressive lung disease, pancreatic insufficiency and elevated sweat chloride levels; CAVD without any other manifest clinical evidence is commonly suggested to be a form of CF with primarily genital expression. We undertook this study to test the hypothesis that men with a CAVD phenotype could be more CF-like than it is usually assumed. Each subject from a population of 42 patients suffering from CAVD was screened for a panel of 16 mutations plus the intron 8 5-thymidine allele of the CF gene (5T), and underwent a thorough clinical evaluation which included a detailed anamnesis, anthropometric data, chest and paranasal sinuses X-rays, pulmonary function tests, sputum cultures, stool chymotrypsin determination, sweat test and, in a limited number of patients, Nasal Potential Difference (NPD) measurement. The genotype analysis detected one compound heterozygote, 23 heterozygotes and 15 individuals carrying the 5T allele; sweat chloride was positive in six, borderline in 11 and negative in 25 subjects; NPD was abnormal in 2/12 patients. Medical history and clinical examination were consistent with respiratory disease in 20 cases; there was radiological evidence of pulmonary hyperinflation in 37/39 and of sinus disease in 20/42 patients; Staphylococcus aureus was cultivated in the sputum of 9/36, Haemophilus influentiae in 3/36 subjects and three patients showed functional evidence of airway obstruction. These findings were equally distributed among sweat positive, borderline and negative patients. These results raise questions about the supposed benignancy of the CAVD condition. A close follow-up of men with CAVD could ascertain potential complications.
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PMID:Evidence of mild respiratory disease in men with congenital absence of the vas deferens. 1065 48

The Hemophilus influenzae Hap adhesin is an autotransporter protein that undergoes an autoproteolytic cleavage event resulting in extracellular release of the adhesin domain (Hap(s)) from the membrane-associated translocator domain (Hap(beta)). Hap autoproteolysis is mediated by Ser(243) and occurs at LN1036-7 and to a lesser extent at more COOH-terminal alternate sites. In the present study, we sought to further define the mechanism of Hap autoproteolysis. Site-directed mutagenesis of residues His(98) and Asp(140) identified a catalytic triad conserved among a subfamily of autotransporters and reminiscent of the SA (chymotrypsin) clan of serine proteases. Amino-terminal amino acid sequencing of histidine-tagged Hap(beta) species and site-directed mutagenesis established that autoproteolysis occurs at LT1046-7, FA1077-8, and FS1067-8, revealing a consensus target sequence for cleavage that consists of ((Q/R)(A/S)X(L/F)) at the P4 through P1 positions. Examination of a recombinant strain co-expressing a Hap derivative lacking all cleavage sites (HapDelta1036-99) and a Hap derivative lacking proteolytic activity (HapS243A) demonstrated that autoproteolysis occurs by an intermolecular mechanism. Kinetic analysis of Hap autoproteolysis in bacteria expressing Hap under control of an inducible promoter demonstrated that autoproteolysis increases as the density of Hap precursor in the outer membrane increases, confirming intermolecular cleavage and suggesting a novel mechanism for regulation of bacterial adherence and microcolony formation.
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PMID:The Hemophilus influenzae Hap autotransporter is a chymotrypsin clan serine protease and undergoes autoproteolysis via an intermolecular mechanism. 1150 35

Ultraviolet-inactivated Hemophilus influenzae transforming DNA recovers its activity when mixed with cell-free extracts of bakers' yeast and exposed to visible light. The active agent in the extract is not used up in the reaction, and purification has not separated it into more than one non-dialyzable component. It differs from the agent in Escherichia coli extract, which produces very similar photoreactivation, but which can be resolved into non-dialyzable and dialyzable components, the latter being used up during illumination. The yeast agent can be salted out of solution and recovered quantitatively; it is inactivated by crystalline trypsin and chymotrypsin and by brief heating at 60 degrees C.-all facts suggesting that it is an enzyme for which ultraviolet lesions in the DNA serve as substrate. The kinetics of recovery are also consistent with such an assumption. This enzyme is unusual both because it is involved in a light-dependent reaction and because it has a non-destructive action on DNA outside an intact cell.
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PMID:Photoreactivation of transforming DNA by an enzyme from bakers' yeast. 1444 Feb 10

The acute phase reactant and protease inhibitor alpha(1)-antichymotrypsin is considered to play a protective role in the airways, but whether it interacts with respiratory bacteria is not known. We analyzed whether the common respiratory pathogens Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and other bacterial species interact with antichymotrypsin. M. catarrhalis was the only species that bound antichymotrypsin among 25 bacterial species tested by flow cytometry and direct binding assay. We compared a series of clinical isolates in addition to wild-type and ubiquitous surface protein-deficient Moraxella to study the nature of antichymotrypsin binding by the bacteria. Experiments with Moraxella mutants revealed that ubiquitous surface proteins A1 and A2 were responsible for the interaction, and using recombinant fragments, a consensus sequence within ubiquitous surface proteins A1 and A2 was defined. Binding of iodine-labeled antichymotrypsin was dose dependent and strong (dissociation constant [K(d)] 24.9-44.8 nM). Moreover, a chymotrypsin activity assay showed that antichymotrypsin, when bound to the bacterial surface, was neutralized. Moraxella antichymotrypsin neutralization is a novel microbial virulence mechanism that may induce excessive inflammation resulting in more exposed extracellular matrix that is beneficial for bacterial colonization.
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PMID:Moraxella-dependent alpha 1-antichymotrypsin neutralization: a unique virulence mechanism. 1809 71