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)

The P2 protein from pathogenic Haemophilus influenzae type b (Hib) functions as a bacterial porin and is one of several immunogenic outer membrane proteins. The P2 gene was expressed in Escherichia coli and the recombinant P2 protein (re-P2) purified to facilitate functional and immunologic studies. P2 was obtained from Hib strain Eagan using PCR and the pET vectors (17b and 11a) were used to produce re-P2 at levels exceeding 30% of the total E. coli proteins. Since previous reports had indicated that P2 was toxic to E. coli, steps were taken to control the toxicity. The plasmid was stabilized by tightly controlling the synthesis of re-P2 prior to induction. Subsequent to induction, re-P2 was sequestered into inclusion bodies rather than to membrane compartments. The refolding of the denatured re-P2 into the trimeric form involved high salt and calcium ions. re-P2 was then purified to homogeneity using gel-filtration and ion-exchange chromatography.
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PMID:Production of Haemophilus influenzae type-b porin in Escherichia coli and its folding into the trimeric form. 782 34

The major outer membrane protein of Haemophilus influenzae type b (Hib) is porin (M(r) 37,782; 341 amino acids). Porins were purified from Hib strains representative of the three outer membrane protein subtypes 1H, 2L and 6U, reconstituted into artificial planar bilayers, and tested for their voltage dependency. At membrane potentials of 50-80 mV, individual Hib 2L and 6U porin channels showed a high probability of undergoing a reversible change to one of several lower conducting substates. Such behaviour was not observed for Hib 1H porin with transmembrane potentials up to 80 mV. The voltage dependence of Hib 2L and 6U porins was asymmetric: it occurred at only one polarity. The asymmetry was also observed for membranes with numerous porins incorporated, suggesting that Hib porin inserted asymmetrically into the bilayer. At macroscopic levels the voltage gating reduced the conductance by 25-50%, implying that the channels closed only partially. Hib 2L porin differs from Hib 1H porin by the substitution Arg166Gln and Hib 6U porin differs from Hib 1H porin by substitutions at ten amino acids including the change Arg166Leu. We conclude that substitutions at Arg166 residue, which is localized to surface-exposed loop number four, are associated with a lowered threshold potential for the voltage gating of Hib porin. This surface-exposed loop may play some role in the conformational changes that occur during voltage gating.
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PMID:Voltage gating of porins from Haemophilus influenzae type b. 829 26

In contrast to studies of many other extremophiles, the molecular characterization of the barophilic or high-pressure-adapted bacteria of the deep ocean is virtually nonexistent. One exception is the discovery that the moderate barophile Photobacterium SS9 preferentially synthesizes a 37-kDa outer membrane protein, designated OmpH, in response to elevated hydrostatic pressure. We report here on the molecular characterization of the ompH gene. The deduced amino acid sequence of mature OmpH is similar to a number of porin proteins, including significant similarity to porin protein P2 from Haemophilus influenzae. It appears likely that OmpH is a unique porin whose synthesis is responsive to changes in the pressure regime of the deep-sea bacterium.
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PMID:Sequence of the ompH gene from the deep-sea bacterium Photobacterium SS9. 839 46

We purified the major outer membrane protein (MOMP), which is the most abundant OMP (with an apparent molecular mass of 40 kDa), from Haemophilus somnus strain 8025. The method involves solubilization of the MOMP with Zwittergent 3-14 and further purification accomplished by ion-exchange and molecular-sieve chromatographies. The amino-terminal sequence of the MOMP showed considerable similarity to those of porin proteins from other gram-negative bacteria. The MOMP of H. somnus is immunogenic to rabbits and calves. Hyperimmune sera from rabbits and calves reacted with both the MOMP and lipopolysaccharides in enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis. The rabbit antiserum to the MOMP was cross-reactive with whole-cell preparations from strains 8025, D1238, NT2301, and 540 at a band with a molecular mass of 40 kDa in immunoblot analysis, although the reactivity of the rabbit antiserum with strain 540 was lower than those with the other strains tested. Two murine monoclonal antibodies (MAbs) to the MOMP were developed. ELISA with the OMP fractions as the antigens showed that one MAb was cross-reactive with the four strains but that the other MAb was reactive with the three strains other than strain 540. These results indicate that the MOMP of H. somnus possesses at least two antigenic determinants and that the MOMP of strain 540 is antigenically different from those of the other strains. The antigenic heterogeneity of the H. somnus MOMP has implications regarding the development of a serotyping system with MAbs that is based on the MOMP epitopes.
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PMID:Purification and partial characterization of the major outer membrane protein of Haemophilus somnus. 841 69

Haemophilus ducreyi contains a major outer membrane protein (MOMP) whose apparent molecular weight is 39,000 to 42,000 for all strains tested. Two monoclonal antibodies (MAbs), designated 9D12 and 2C7, bound to the MOMP for all strains of H. ducreyi tested. As reported previously, MAb 9D12 was H. ducreyi specific (E. J. Hansen and T. A. Loftus, Infect. Immun. 44:196-198, 1984). MAb 2C7 bound to all members of the family Pasteurellaceae tested, suggesting that the MAbs bound to distinct epitopes on the MOMP. The MOMP was purified by extraction of whole cells with Zwittergent and ion-exchange chromatography. A peak eluted from a cation-exchange column contained three bands. All three species bound both MAbs, and the fraction yielded a single N-terminal amino acid sequence, suggesting that the bands represented different conformations of the MOMP. The MOMP was heat modifiable, contained two cysteine residues, and was cationic at pH 8.0, features not usually associated with classical porin proteins. The N-terminal amino acid sequence and total amino acid content of the MOMP were homologous to the OmpA proteins of members of the family Enterobacteriaceae and the OmpA-like protein of Actinobacillus actinomycetemcomitans. An OmpA-specific polyclonal serum bound to the MOMP, and MAb 2C7 bound to Haemophilus influenzae protein 5, an OmpA-like protein, indicating that the MOMP was antigenically related to OmpA. These data indicated that the most abundant protein in the outer membrane of H. ducreyi was not a classical porin and belonged to the OmpA family of proteins.
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PMID:The major outer membrane protein of Haemophilus ducreyi is a member of the OmpA family of proteins. 845 37

We previously demonstrated a close relationship between the outer membranes of Haemophilus parainfluenzae (HP) antigens (OMHP) and IgA nephropathy (IgAN). Our objective was to clarify the relationship among IgA, IgG, and IgM class antibody against OMHP in the sera of 44 patients with IgAN and 62 patients with other glomerular diseases (OGD) by ELISA. Patients with IgAN showed a significantly higher level of IgA antibodies (P less than 0.0005) and IgG antibodies (P less than 0.001) against OHMP, than did patients with OGD. Positive correlations were observed between IgA and IgG antibodies, between IgA and IgM antibodies, and between IgG and IgM antibodies against OMHP in the sera of patients with IgAN. Immunoblotting showed that IgA, IgG, or IgM antibodies against OMHP in the sera of all patients with IgAN bound to components of OMHP. Amino acid sequences of three components of OMHP recognized by the sera from patients with IgAN revealed homology with those reported for outer membrane protein (OMP) P6 precursor, OMP P5, and P2 porin protein of H. influenzae. Results suggest that patients with IgAN have glomerular deposits of OMP P6 precursor, OMP P5, or P2 porin protein of HP, and a specific increase in the production of IgA antibodies against OMHP via polyclonal activation against these, with switching of production from one isotype to another, e.g. from IgM to IgA.
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PMID:Circulating IgA, IgG, and IgM class antibody against Haemophilus parainfluenzae antigens in patients with IgA nephropathy. 862 25

The major diffusion channel in the outer membrane of Haemophilus influenzae type b (Hib) is porin (341 amino acids; Mr 37 782). The Hib porin gene was cloned and overexpressed in Bacillus subtilis. Recombinant Hib porin (Bac porin), having aggregated into inclusion bodies, was purified under denaturing conditions and subsequently refolded. To compare Bac porin that is intrinsically devoid of lipooligosaccharides versus native Hib porin, the properties of Bac porin were assessed by the following four criteria: circular dichroism spectroscopy, channel formation in planar bilayers, resistance to trypsin digestion and formation of the conformational epitope recognized by an anti-Hib porin monoclonal antibody. We conclude that in the absence of lipooligosaccharides, Bac porin was refolded into a functional form which closely resembled the structure of Hib porin.
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PMID:Purification and refolding of recombinant Haemophilus influenzae type b porin produced in Bacillus subtilis. 877 68

A polyclonal antibody prepared against the 35 kDa outer membrane protein (a putative porin) of Pasteurella (P.) multocida revealed binding to the 36 kDa major outer membrane protein (major Omp) of Haemophilus (H.) paragallinarum, to the 38 kDa major Omp of P.gallinarum, to the 39 kDa major Omp of P.volantium and to the 38.5 kDa major Omp of P. avium in immunoblotting studies. Comparison of N-terminal amino acid sequences also confirmed the relationship between the major Omps of most of the members of the family Pasteurellaceae.
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PMID:A comparative study of the major outer membrane proteins of the avian haemophili and Pasteurella gallinarum. 883 67

We have recently demonstrated glomerular deposition of outer membranes of Haemophilus parainfluenzae (HP) antigens (OMHP) and the presence of IgA antibody against OMHP in patients with IgA nephropathy (IgA-N). In this study, we analyzed IgA-, IgG-, and IgM-classes of antibodies against OMHP, and the relationship between these antibodies and renal lesions in IgA-N. The subjects included 44 patients with IgA-N and 62 patients with outer glomerular diseases (OGD); the latter group consisted of 23 patients with predominantly IgG or IgM deposits and small amounts of IgA in the mesangium (group A), and 39 with IgG or IgM deposits without IgA (group B). IgA, IgG, and IgM antibodies against OMHP in patients sera were detected by enzyme-linked immunosorbent assay (ELISA). Immunoblotting demonstrated that the IgA, IgG, and IgM antibodies against OMHP in the sera of IgA-N patients bound to components of OMHP with molecular weights of 19.5, 30, and 40.5 kD. The amino acid compositions of these three OMHP components were similar to those reported for the outer membrane protein (OMP) P6 precursor, OMP P5, and OMP P2 (porin) of Haemophilus influenzae. Both IgA-N and group A patients, (i.e. those with IgA-related renal disease), demonstrated a significantly higher level of IgA antibodies against OMHP than did group B patients. However, only IgA-N patients revealed a significant correlation between the IgA-antibody titer and degree of glomerular changes. IgA-N patients with macroscopic hematuria or arterio(lo)sclerosis had a significantly higher IgA antibody titer than other IgA-N patients. There was no relationship between renal lesions and IgG or IgM antibody titers in any group. These findings suggest that IgA antibodies against OMHP are significantly increased in patients with IgA-related renal disease compared to those without mesangial IgA deposits and that a significant relationship between these antibodies and renal lesions exists only in patients with IgA-N.
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PMID:Role of IgA, IgG, and IgM antibodies against Haemophilus parainfluenzae antigens in IgA nephropathy. 895 16

Aboriginal infants in the Northern Territory of Australia experience recurrent otitis media from an early age. Nonencapsulated Haemophilus influenzae (NCHi) colonization of the nasopharynx initially occurs within weeks of birth, persists throughout infancy and most of childhood, and contributes to otitis media. We established previously that the high carriage rates of NCHi in these infants result from concurrent and successive colonization with multiple strains, with sequential elimination of dominant strains. We have now sequenced loops 4, 5, and 6 of the NCHi P2 porin gene and characterized several strains with prolonged carriage times. Furthermore, despite a wide diversity of P2 gene sequences, we have four examples of P2 gene identity for strains with different genetic backgrounds as characterized by PCR ribotyping and randomly amplified polymorphic DNA typing, which leads us to suggest that the P2 gene has been transferred between strains. We also discuss the possibility that the paradoxical observation of cocolonization and prolonged carriage of P2-identical strains is related to immune suppression or tolerance in the host.
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PMID:Nonencapsulated Haemophilus influenzae in Aboriginal infants with otitis media: prolonged carriage of P2 porin variants and evidence for horizontal P2 gene transfer. 911 89


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