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)

Cytochromes of the a-, b-, c- and d-type become reduced when intact cells of Hemophilus parainfluenzae have become anaerobic following respiration with substrates such as formate or succinate, as shown previously (J. Biol. Chem. (1970) 254, 5096-5100). In the presence of formate after depletion of O2, there is an unusual two-step time course of reduction of the membrane-bound cytochrome c. The proportion of the cytochrome c which is reduced during the second stage is oxidizable by either nitrate or H2O2 and is reduced again when the nitrate or H2O2 have been depleted. We conclude that the observed two-stage reduction of cytochrome c results from the presence of an oxidant, probably H2O2, produced by reaction of formate dehydrogenase with O2. This was shown by the effects of cyanide, catalase and O2. In addition, no evidence for the production of the oxidant is seen when succinate is the substrate oxidized. Although measurements of absorption spectra indicated only one species of cytochrome c, kinetic evidence is presented for some separation of the cytochrome c into more than one electron transport pathway.
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PMID:Oxidation and reduction of membrane-bound cytochrome c in Hemophilus parainfluenzae. Reaction with oxygen, hydrogen peroxide and nitrate. 18 42

The natural product 2-chloro-3,11-tridecadiene-5,7,9-triyn-1-ol (1) photosensitized the inactivation of Escherichia coli in the presence of near-ultraviolet light (320-400 nm; NUV) under both aerobic and anaerobic conditions. A series of E. coli strains differing in DNA repair capabilities and catalase proficiency exhibited indistinguishable inactivation kinetics following treatment with the chemical plus NUV. The presence of carotenoids did afford some protection to E. coli against inactivation under aerobic conditions, consistent with the involvement of singlet oxygen. The photosensitized hemolysis of human erythrocytes occurred more rapidly in the absence than in the presence of oxygen. Aerobically, the onset of hemolysis was partially inhibited by NaN3 and by 2,6-di-t-butyl-4-methylphenol (BHT) but not by superoxide dismutase (SOD). The aerobic lipid peroxidation observed in the membranes of erythrocyte ghosts was completely inhibited by BHT, and partially by NaN3, but not by SOD. These results suggest that either lipid peroxidation of the membrane is not the main cause of photohemolysis or that BHT has insufficient access to intact erythrocyte lipids to protect them. Aerobically, crosslinking of membrane proteins was also observed; it was not affected by SOD, but was partially inhibited by BHT and NaN3. The anaerobic photosensitized hemolysis of erythrocytes was more rapid; a radical mechanism was suggested since BHT inhibited the hemolysis to a greater extent than under aerobic conditions. Neither lipid peroxidation nor protein crosslinking was observed under conditions believed to be anaerobic. A light-dependent electron transfer to cytochrome c was obtained under argon but not under oxygen. Although induced mutations were not observed in the experiments with E. coli, 1 was capable of damaging both supercoiled pBR322 and Haemophilus influenzae transforming DNA in a manner that seemed to be equivalent under aerobic and anaerobic conditions. In conclusion, 1 can behave as typical photodynamic molecule under aerobic conditions but, in contrast to most photodynamic molecules, it is also phototoxic under anaerobic conditions. The extent to which the radical reactions detected under anaerobic reactions compete with the photodynamic processes when oxygen is present is not known.
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PMID:Photosensitization by 2-chloro-3,11-tridecadiene-5,7,9-triyn-1-ol: damage to erythrocyte membranes, Escherichia coli, and DNA. 160 51

Anthracene is a photodynamic compound in vitro. In the presence of oxygen, it is known to generate singlet oxygen and participate in Type II reactions. In aqueous solution, it also participates in Type I reactions, such as in the photoreduction of cytochrome c, which can be suppressed by superoxide dismutase. In argon, direct photoreduction of cytochrome c also takes place. Anthracene induces the photodynamic hemolysis of human erythrocytes and inactivates Escherichia coli cells photodynamically. By using a series of E. coli strains differing in DNA repair capabilities and catalase proficiency, sensitivity to inactivation by anthracene plus NUV was correlated with catalase deficiency rather than with particular repair deficiencies. The fact that carotenoid genes cloned and expressed in E. coli offered partial protection suggests that the membrane may be one possible target for inactivation by anthracene plus NUV. Anthracene plus NUV inactivated Haemophilus influenzae transforming DNA and led to nicking of supercoiled pBR322 DNA in vitro. In vivo, therefore, anthracene is a phototoxic molecule whose cytotoxicity could be the result of damage to more than one target.
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PMID:Light-dependent cytotoxic reactions of anthracene. 196 59

Photoreactivation repair (Phr) activities in cell extracts of 13 different yeast species were measured by the Haemophilus influenzae transformation assay. Five species including Schizosaccharomyces pombe showed no or low enzymatic activity. In contrast to the other species, chromosomal DNAs of these 5 species did not show detectable hybridization using a DNA fragment of the photolyase PHR1 gene of Saccharomyces cervisiae as a probe even at a low stringency condition. When the PHR1 gene was attached to the 5'-flanking sequence of the iso-1-cytochrome c (CYC-1) gene of S. cerevisiae and introduced into S. pombe cells, the transformants acquired a high Phr activity, indicating that the PHR1 gene alone can provide a Phr-negative species with this repair activity and the light-absorbing cofactor(s) must be present in S. pombe. Our results also demonstrated that the 5'-flanking sequence of the S. cerevisiae CYC-1 gene works in S. pombe as a regulatory element.
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PMID:Existence and expression of photoreactivation repair genes in various yeast species. 291 Dec 65

Although Haemophilus influenzae requires heme for growth, the source of heme during invasive infections is not known. We compared heme, lactoperoxidase, catalase, cytochrome c, myoglobin, and hemoglobin as sources of heme for growth in defined media. The minimum concentration of heme permitting unrestricted growth of strain E1a, an H. influenzae type b isolate from cerebrospinal fluid, was 0.02 micrograms/ml. Using molar equivalents of heme as lactoperoxidase, catalase, cytochrome c, myoglobin, and hemoglobin, we determined that myoglobin and hemoglobin permitted unrestricted growth at this concentration. To determine the ability of host defenses to sequester heme from H. influenzae, we used affinity chromatography to purify human haptoglobin and hemopexin, serum proteins which bind hemoglobin and heme. Plate assays revealed that 12 strains of H. influenzae acquired heme from hemoglobin, hemoglobin-haptoglobin, heme-hemopexin, and heme-albumin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membrane proteins of strain E1a grown in heme-replete and heme-restricted conditions revealed a heme-repressible outer membrane protein with an apparent molecular mass of 38 kilodaltons. These results demonstrated that, unlike Escherichia coli, H. influenzae may acquire heme from hemoglobin-haptoglobin. H. influenzae also may acquire heme from hemopexin and albumin, which have not been previously investigated. The role of outer membrane proteins in the acquisition of heme is not yet clear.
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PMID:Protein sources of heme for Haemophilus influenzae. 302 98

The catabolism of glucose by Haemophilus parainfluenzae affected the formation of the primary dehydrogenases of the membrane-bound electron transport system. The formation of other components of the respiratory system, 2-demethyl vitamin K(2), cytochrome b(1), cytochrome c(1), and the cytochrome oxidases a(1), a(2), and o, is not affected by the catabolism of glucose. The formation of all components of the electron transport system is controlled by the identity and concentration of the terminal electron acceptors present in the growth medium.
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PMID:Effect of glucose on the formation of the membrane-bound electron transport system in Haemophilus parainfluenzae. 428 51

The composition of the membrane-bound electron transport system of Haemophilus parainfluenzae underwent modification in response to the terminal electron acceptor in the growth medium. H. parainfluenzae was able to grow with O(2), nitrate, fumarate, pyruvate, and substrate amounts of nicotinamide adenine dinucleotide (NAD) as electron acceptors. When O(2) served as the electron acceptor and its concentration was lowered below 20 mum, the bacteria formed more cytochromes b, c, a(1), a(2), and o than were present in the cells grown at 150 to 200 mum O(2). Nitrate and nitrite reductase activities also appeared during growth at the low O(2) concentrations in the absence of added nitrate. Cytochrome levels in cells grown anaerobically with fumarate, pyruvate, or NAD as terminal acceptors were similar to those formed in cells grown at low O(2) concentrations. Cells grown with nitrate had higher levels of cytochromes c, b, and o, and of nitrate and nitrite reductases, than did cells grown with the other acceptors. The formation of cytochrome oxidase a(2) was repressed by the presence of nitrate in the growth medium. The critical O(2) concentration (the O(2) concentration at which the rate of O(2) uptake becomes demonstrably dependent on the O(2) concentration) was about 100 mum in cells grown with nitrate and about 15 mum in cells grown with the other acceptors. A mutant of H. parainfluenzae was found to make about 10% as much cytochrome c as the wild type, and its formation of cytochrome a(2) was not repressed by nitrate. The critical O(2) concentration of the mutant was high when it was grown with nitrate, suggesting that the high levels of cytochrome c and the absence of cytochrome a(2) from the wild type are not responsible for the high critical O(2) concentration. The modifications of the respiratory system induced by changing the terminal electron acceptor were inhibited by the presence of chloramphenicol, which suggests that protein synthesis is involved.
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PMID:Effect of nitrate, fumarate, and oxygen on the formation of the membrane-bound electron transport system of Haemophilus parainfluenzae. 431 51

Logarithmically growing Haemophilus parainfluenzae lost 15 to 20% of the phospholipids, demethyl vitamin K(2), cytochrome b, and cytochrome c, and 50% of the lipopolysaccharide when incubated in ethylenediaminetetraacetic acid (EDTA)-tris-(hydroxymethyl)aminomethane (Tris) for 10 min. This loss of membrane components occurred without loss in viability, and the lost components were recovered as membrane fragments in the surrounding buffer. The phospholipids recovered in the membrane fragments had a slightly lower specific activity than the phospholipids in the residue. Lysis of a portion of the cells could not account for the release of membrane components, as the cells lost neither glucose-6-phosphate dehydrogenase activity not deoxyribonucleic acid. The treated cells were osmotically stable and contained the same proportions of the individual phospholipids as pretreatment cells. Prolongation of the EDTA-Tris treatment did not induce further loss of phospholipid or demethyl vitamin K(2), but caused a decrease in viability. If the cells were returned to the growth medium after 10 min, the cells immediately resumed growth at the pretreatment rate. During growth in the recovery period, the phospholipids increased logarithmically in the pretreatment rate. During growth in the recovery period, the phospholipids increased logarithmically in the pretreatment proportions, although there was a marked decrease in the turnover and a shift from the use of extracellular lipid precursors to the use of intracellular pools of precursors.
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PMID:Release of membrane components from viable Haemophilus parainfluenzae by ethylenediaminetetraacetic acid-tris(hydroxymethyl)-aminomethane. 498 95

Spectral analyses with subcellular fractions derived from Haemophilus parasuis demonstrated that this organism could synthesize membrane-bound and soluble CO- and NO-binding c-type cytochromes in addition to the membrane-bound cytochromes d, a1, b, and c; cytochromes d, a1, and o were identified as potential oxidases. The membrane-bound and soluble CO- and NO-binding cytochromes c were not spectrally variant cytochromes c, and the redox properties of the soluble cytochrome (reducible by NADH but not by succinate or ascorbate plus N,N,N',N'-tetramethyl-p-phenylenediamine) suggested that it, at least, was a low-potential cytochrome; up to 68% of the soluble cytochrome c could be released from the organisms by osmotic-shock treatment, demonstrating its extracytoplasmic location. The cytochrome content of H. parasuis was influenced by both the composition of the growth medium and the phase of growth; it is suggested that the bacterial concentration and growth rate, and therefore the availability of oxygen, regulated cytochrome synthesis.
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PMID:The cytochrome complement of Haemophilus parasuis. 648 1

The napB gene of the pathogenic bacterium Haemophilus influenzae encodes a dihaem cytochrome c, the small subunit of a heterodimeric periplasmic nitrate reductase (Nap). Recombinant NapB was overproduced in Escherichia coli, purified to near-homogeneity and crystallized using the hanging-drop method. Thin quadrilateral plates were grown under various conditions but proved to be unsuitable for X-ray analysis. However, a single crystal was grown using 1.75 M ammonium sulfate in 0.1 M sodium acetate pH 5.5, from which a native data set could be collected to 1.8 A resolution using synchrotron radiation. Using the same conditions, further crystals were obtained by microseeding. The space group was determined to be P42(1)2, with unit-cell parameters a = 77.55, b = 77.55, c = 28.64 A and an unusually low solvent content of 16.5%, assuming there to be one molecule of NapB in the asymmetric unit. Analysis of the dissolved crystals indicated that partial proteolysis of the protein had occurred. Taking the molecular mass of the crystallized form ( approximately 8500 Da) into account, the solvent content was estimated to be 53%, with a V(M) value of 2.64 A(3) Da(-1).
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PMID:Crystallization and preliminary X-ray analysis of the recombinant dihaem cytochrome c (NapB) from Haemophilus influenzae. 1122 19


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