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)

A wild-type Haemophilus influenzae type b (Hib) genomic DNA library was constructed in the plasmid shuttle vector pGJB103. A virulence-deficient lipooligosaccharide (LOS) mutant of Hib was used as a recipient for genetic transformation to screen this Hib genomic DNA library for genes involved in LOS expression. A recombinant plasmid containing a 7.8 kb PstI fragment of Hib DNA was shown to transform this LOS mutant to reactivity with a monoclonal antibody (mAb) specific for a wild-type LOS epitope. Transformation of two different virulence-deficient LOS mutants with a 4.4 kb BglII fragment of this recombinant plasmid yielded transformants which expressed LOS that bound the wild-type LOS-specific mAb and yielded profiles in sodium dodecyl sulphate/polyacrylamide gradient gel electrophoresis different from those of the original LOS mutants. These transformants with structurally altered LOS molecules also exhibited increased virulence in an animal model for invasive Hib disease. The virulence-transforming ability was further localized to a 1.8 kb BglII-AlwNI fragment of the Hib DNA insert. Nucleotide sequence analysis indicated the presence of a single large open reading frame within this fragment. This open reading frame contained 19 consecutive repeats of the tetramer CAAT near the 5' end. Linker insertion mutagenesis was used to demonstrate directly the involvement of this open reading frame in both LOS biosynthesis and virulence expression by Hib.
Mol Microbiol 1991 May
PMID:Molecular cloning of a gene involved in lipooligosaccharide biosynthesis and virulence expression by Haemophilus influenzae type B. 195 89

A Haemophilus influenzae DNA library was prepared in the vector lambda EMBL3, and recombinant phage were screened for the pilin gene (pil) using a synthetic oligonucleotide. Southern blot analysis of the positive clones revealed a 2.5kb PstI/PvuI fragment that hybridized with the oligonucleotide probe. This fragment was subcloned into pBR322 and sequenced. The nucleotide sequence disclosed an open reading frame of 653 bases. The deduced amino acid sequence corresponded with the known amino acid sequence of the purified pilin protein. Primer extension analysis using total RNA from piliated H. influenzae cells delineated a start site for the gene, -10 and -35 promoter regions, and a ribosome-binding site. No transcripts were seen with the RNA derived from a non-piliated strain. Southern blots of DNA from a number of H. influenzae strains revealed homology with the pil structural gene. DNA from a non-piliated strain of H. influenzae also hybridized with the pil probe. Transcriptional and translational studies were performed in Escherichia coli with plasmids containing: (i) the pil gene on the 2.5 kb PstI/PvuI fragment, (ii) the pil gene fused to the phoA gene, and (iii) the pil gene present on a 12.2 kb insert containing extensive H. influenzae DNA flanking the pil gene. The results suggest that the H. influenzae pil gene is expressed in Escherichia coli, but from a promoter other than the one used in H. influenzae.
Mol Microbiol 1990 Feb
PMID:Molecular analysis of the Haemophilus influenzae type b pilin gene. 197 Oct 86

A library of genomic DNA fragments from Haemophilus influenzae type b (Hib) DL42 was constructed in plasmid pBR322, transformed into Escherichia coli strain RR1, and screened for recombinant clones with haemin-binding activity by plating onto haemin-containing agar. Expression of haemin-binding activity by clones correlated with the expression of a protein with an apparent molecular weight of 51,000 (51K) that was also recognized by anti-Hib strain DL42 serum in immunoblots. One recombinant clone, designated pHM2, with the smallest DNA insert (3.62 kb) was characterized further. Ethanol inhibition of expression of pHM2 in minicells revealed that the 51K protein was the result of a processing event involving a larger precursor. E. coli RR1(pHM2) adsorbed haemin in liquid suspensions as well as from solid media. Subcloning of a 2.6 kb fragment of pHM2 into a shuttle vector permitted the construction of a recombinant Hib clone, DL42(pHM1002), which overexpressed the 51K haemin-binding protein. This 51K protein appears to be peripherally associated with the inner, and possibly outer, membranes of Hib. Affinity chromatography on haemin-agarose was utilized to purify the haemin-binding protein from both E. coli RR1(pHM2) and Hib DL42(pHM1002) to near homogeneity. The use of the antibiotic globomycin in a minicell expression system and radioimmunoprecipitation analysis of Hib proteins intrinsically radiolabelled with [3H]-palmitate indicated that the 51K haemin-binding protein is a lipoprotein.
Mol Microbiol 1991 Feb
PMID:Molecular cloning, partial purification, and characterization of a haemin-binding lipoprotein from Haemophilus influenzae type b. 204 70

The nucleotide sequence of a 5.1 kb region in the Haemophilus influenzae type b capsulation locus has been determined and found to contain four open reading frames: bexD, bexC, bexB, and bexA. Comparison of the deduced products of bexC, bexB, and bexA to known proteins, and TnphoA mutagenesis, suggests that they form components of an ATP-driven polysaccharide export apparatus. Furthermore, close sequence similarity between BexA and BexB and products of the kpsT and kpsM genes at the Escherichia coli K5 capsulation locus (Smith et al., 1990--accompanying paper) suggests that capsulation genes in these organisms may have a common ancestry.
Mol Microbiol 1990 Nov
PMID:The bex locus in encapsulated Haemophilus influenzae: a chromosomal region involved in capsule polysaccharide export. 208 45

The complete nucleotide sequence has been determined of a region of the Escherichia coli K5 antigen gene cluster postulated to encode functions for the translocation of capsular polysaccharide across the inner membrane. This revealed two genes, designated kpsM and kpsT, organized in a single transcriptional unit. Analysis of the predicted amino acid sequence of the KpsM and KpsT proteins indicates that they may function as dual components in a polysaccharide export system analogous to the periplasmic binding protein-dependent transport systems of Gram-negative bacteria. We propose that the KpsT protein acts as an energizer, coupling ATP hydrolysis to the transport process mediated by the KpsM protein. Extensive sequence homology between the KpsM and KpsT proteins and the products of the bexB and bexA genes present in the capsulation (cap) locus of Haemophilus influenzae, indicates that a common mechanism for the export of polysaccharide across the inner membrane may exist in these two micro-organisms.
Mol Microbiol 1990 Nov
PMID:Molecular analysis of the Escherichia coli K5 kps locus: identification and characterization of an inner-membrane capsular polysaccharide transport system. 208 46

Outer membranes from Haemophilus pleuropneumoniae grown under iron-replete and iron-restricted conditions in vitro were analysed by means of SDS-PAGE and immunoblotting. Iron restriction resulted in the appearance of two or more novel polypeptides in the molecular size range of 96-102 kD and an increased amount of a 79 kD polypeptide. These polypeptides were recognized by porcine immune sera indicating their production by H. pleuropneumoniae during growth in vivo. Although soluble siderophore production could not be detected, growth of the organisms on an iron-restricted medium was enhanced by the presence of porcine transferrin but not by bovine or human transferrin. The results suggest that H. pleuropneumoniae possesses a specific transferrin receptor, perhaps in the form of an iron-regulated outer membrane protein.
Mol Microbiol 1989 Aug
PMID:Responses of Haemophilus pleuropneumoniae to iron restriction: changes in the outer membrane protein profile and the removal of iron from porcine transferrin. 253 2

In previous studies, it has been demonstrated that outer membrane protein P2 from Haemophilus influenzae type b has porin activity and that antibody directed against P2 is protective in an infant rat bacteraemic model. Outer membrane protein subtyping has been employed to subclassify type b Haemophilus isolates. Strain MinnA has the outer membrane protein subtype 1H and is representative of the dominant clonal group of disease-producing isolates in the United States. In the present study, the P2 gene from strain MinnA was employed to probe EcoRI- and Pvull-digested chromosomal DNA from 24 Haemophilus influenzae type b isolates representative of the common outer membrane protein subtype groups observed throughout the world. Restriction fragment length polymorphisms were identified for the members of the outer membrane protein subtype 3L group, but not for the other subtypes examined. The P2 gene from each of four prototype isolates was then cloned, sequenced and compared to the previously reported sequence of the strain MinnA gene. The P2 gene from each of two isolates with the outer membrane protein subtype 3L was identical to the MinnA P2 sequence. The P2 gene from a subtype 2L isolate differed by a single nucleotide and the gene from a subtype 6U isolate differed by 13 nucleotides. Thus, the P2 protein is highly conserved among type b isolates.
Mol Microbiol 1989 Dec
PMID:Diversity of the outer membrane protein P2 gene from major clones of Haemophilus influenzae type b. 257 96

Nontypable Haemophilus influenzae (NTHI) is being increasingly recognized as a cause of both adult pneumonia and acute infectious exacerbations in chronic bronchitis. We used a mouse model to study the immune enhancement of pulmonary clearance of NTHI after a primary immunization. BALB/c mice were immunized with whole NTHI either by intraperitoneal (i.p.) or intratracheal (i.t.) routes. There was 10-fold more NTHI-directed antibody detected in the serum of the i.p.-immunized mice than in the serum from the i.t.-immunized animals. Western blot analysis revealed that these antibodies were directed against both NTHI lipooligosaccharide and the various outer membrane proteins of NTHI. The development of NTHI-directed antibodies in serum was associated with significant enhancement of early pulmonary clearance of NTHI. Six hours after delivery of an endobronchial challenge with NTHI, the i.p.-immunized mice had cleared most of the organisms from their lungs, while the i.t.-immunized mice did not clear NTHI any more rapidly than did unimmunized mice. Serum from the i.p.-immunized mice caused more than 99% uptake of NTHI in an in vitro opsonophagocytic assay, while serum from i.t.-immunized mice stimulated little or no phagocytosis of this organism. Opsonophagocytosis of NTHI was obtained with bronchoalveolar lavage (BAL) fluid collected from i.p.-immunized mice 6 h after, but not before, an endobronchial challenge with NTHI. Intravenous injection of an opsonic IgG monoclonal antibody directed against NTHI lipooligosaccharide resulted in both the appearance of this antibody in the alveolar spaces of the unperturbed lung and enhanced pulmonary clearance of NTHI. These data indicate that the i.p. (systemic) route of immunization is more effective than the i.t. route in establishing pulmonary immunity to NTHI in this model system. Furthermore, immune enhancement of clearance of NTHI from the lungs after a primary immunization apparently results from the exudation of opsonic and bactericidal antibodies from the serum into the alveolae in response to the inflammatory challenge.
Am J Respir Cell Mol Biol 1989 Sep
PMID:Effect of primary immunization on pulmonary clearance of nontypable Haemophilus influenzae. 262 60

Fluoranthene, a non-carcinogenic polycyclic aromatic hydrocarbon, inactivates Escherichia coli cells in the presence of near-ultraviolet light (NUV; 300-400 nm). E coli cells carrying defects in the uvrA6 or katF genes are sensitized to inactivation by the simultaneous treatment with fluoranthene and NUV, suggesting that DNA is a target and that hydrogen peroxide is generated. Haemophilus influenzae transforming DNA can be inactivated by the simultaneous treatment with fluoranthene and NUV confirming DNA as a target. Using the photooxidation of imidazole and histidine as probes, fluoranthene was found to generate singlet oxygen in organic and aqueous media. In water, it participated in electron transfer reactions, reducing nitro blue tetrazolium as well as ferricytochrome C. This reduction took place both in the presence of air, where superoxide anion was formed, and under argon. Simultaneous treatment with fluoranthene and NUV was incapable of inducing histidine-independent mutations. Simultaneous treatment with fluoranthene and NUV was incapable of inducing the uvrA gene product as evidenced by the absence of the induction of beta-galactosidase in an E coli operon fusion strain [uvrA215::Mud(Ap,lac)].
Environ Mol Mutagen 1987
PMID:Phototoxic effects of fluoranthene, a polycyclic aromatic hydrocarbon, on bacterial species. 282 96

The modification genes of Flavobacterium okeanokoites and Haemophilus galinarum have been cloned into the vector pBR322 and expressed in Escherichia coli cells. FokI methylase gene is contained on a 3.80 kb piece of F. okeanokoites DNA. Plasmid constructs carrying this fragment of DNA are resistant to digestion by FokI restriction endonuclease but are sensitive to cleavage by HindIII, EcoRI and PstI. Unmodified lambda DNA molecules, exposed in vitro to cell extracts prepared from cells habouring this plasmid, became resistant to digestion by FokI. The smallest HgaI methylase clone carries the pBR322 plasmid containing a 3.50 kb piece of H. galinarum DNA. This plasmid is resistant to digestion by HgaI. Neither the FokI nor the HgaI restriction endonuclease was detected in either clone. This is the first report of cloning modification genes whose protein products recognise asymmetric nucleotide sequences.
Mol Gen Genet 1987 Oct
PMID:Cloning of two type II methylase genes that recognise asymmetric nucleotide sequences: FokI and HgaI. 282 84


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