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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ampicillin-resistant Haemophilus influenzae strain Ve445 which caused purulent meningitis and septicaemia in a newborn child in Germany contained a 4.4 megadalton (Mdal) plasmid (pVe445) and produced a TEM type beta-lactamase. The transformation to ampicillin resistance of a sensitive Escherichia coli strain with isolated pVe445 DNA proved that the structural gene for the beta-lactamase resided on this plasmid genome. Molecular DNA-DNA hybridization studies and electron microscope DNA heteroduplex analysis indicated that pVe445 probably contained 38 to 41% of the ampicillin translocation DNA segment (TnA) found on R factors of enteric origin. The TnA fragment present in pVe445 most likely does not contain both of the inverted repeat sequences of TnA. DNA-DNA polynucleotide sequence studies indicated that the 4.4 Mdal plasmid pVe445 was unrelated to the 30 to 38 Mdal H. influenzae R plasmids but was closely related to the 4.1 Mdal ampicillin resistance specifying H. influenzae plasmid RSF0885 isolated in the U.S.A. The H. influenzae plasmid pVe445 shared 91% of its base sequences with the beta-lactamase specifying Neisseria gonorrhoeae plasmid pMR0360 (4.4 Mdal) and had 85% of its base sequences in common with the beta-lactamase specifying N. gonorrhoeae plasmid pMR0200 (3.2 Mdal). All of the four 3.2 to 4.4 Mdal beta-lactamase specifying R plasmids of H. influenzae and N. gonorrhoeae investigated probably have a common evolutionary origin.
J Gen Microbiol 1979 Mar
PMID:Molecular characterization of a small Haemophilus influenzae plasmid specifying beta-lactamase and its relationship to R factors from Neisseria gonorrhoeae. 11 Sep 7

Six strains of Haemophilus species, pathogenic to chickens, required 1-0 to 1-5% (w/v) NaCl for optimum growth. The requirement was for Na+ rather than NaCl. A sodium salt buffer influenced the optimum NaCl requirement and enhanced growth. Each strain required a different concentration of NADH for an optimum rate of growth.
J Gen Microbiol 1977 Feb
PMID:The effect of sodium chloride and NADH on the growth of six strains of haemophilus species pathogenic to chickens. 19 32

The nutritional requirements of 43 strains of Haemophilus influenzae isolated from clinical and normal flora sources were investigated. Two defined minimal media were developed by modifying the medium of Herriott et al. (1970):74% of the strains could grow on the minimal media and Herriott's medium; the remaining strains could not grow on any of these media.
J Gen Microbiol 1979 Aug
PMID:Simplified media for the growth of Haemophilus influenzae from clinical and normal flora sources. 31 98

A mutant of Haemophilus influenzae which does not discriminate between low efficiency (LE) and high efficiency (HE) markers has been isolated. The mutant does not differ wild type in its sensitivity to ultraviolet radiation, methyl methanesulfonate (MMS) mitomycin C, and nitrous acid. Spontaneous mutation frequencies for three loci studied are 10- to 30-fold higher in the mutant than in the wild type strain. Low- and high-efficiency transforming markers are equally UV-resistant when assayed on this mutant. This mutant is thus similar to the hex mutant of Streptococcus pneumoniae.
Mol Gen Genet 1979 Sep
PMID:A hex mutant of Haemophilus influenzae. 31 97

The tetracycline-resistant Haemophilus influenzae strains LU121 and FR16017, recently isolated in West Germany, each harbour a plasmid; that of the former (pLU12U) has a mol. wt of 31.5 X 10(6) and that of the latter (pFR16017) has a mol. wt of 33 X 10(6). Conjugation and DNA-DNA hybridization studies have shown that both plasmids are self-transmissible and carry tetracycline-resistance genes. The purified plasmid DNA of H. influenzae strain LU121 transformed a sensitive Escherichia coli strain to tetracycline resistance. The two R factors are closely related to the H. influenzae plasmid specifying ampicillin resistance (pKRE5367). Electron microscope DNA heteroduplex analysis indicated that pLU121 and pFR15017 probably carry the tetracycline-resistance transposon TnD and that pKRE5367 probably carries the ampicillin-resistance transposon TnA. There is more than one integration site for the insertion which probably represents TnD in pFR15017. All three plasmids have a similar plasmid core and could have a common evolutionary origin.
J Gen Microbiol 1978 Apr
PMID:Molecular properties of transmissible R factors of Haemophilus influenzae determing tetracycline resistance. 34 29

A collection of 426 Haemophilus strains isolated from people with infectious diseases and from the normal flora of mucous membranes in humans and various animal species was studied in an attempt to revise and improve the taxonomy of the genus Haemophilus. The examinations included the determination of a number of biochemical and physiological properties, of which several had not previously been applied to the taxonomy of haemophili. The resulting data reavealed many hitherto unrecognized characters of taxonomic significance and several of the species can now be more accurately defined. The classification presented is supported by the DNA base composition of a large number of representative strains. A diagnostic key to the different taxa is presented. Haemophilus influenzae and H. parainfluenzae have been subdivided into a number of biotypes. It is possible to demonstrate a relationship between the individual biotypes of H. influenzae and the origin of the strains assigned to them. The results indicate that H. aegyptius, H. parahaemolyticus and H. paraphrohaemolyticus do not merit specific status. Four unnamed taxa of V-factor-dependent haemophili have been recognized. The name Haemophilus segnis is proposed for one of these taxa, which consists mainly of strains isolated from the human oral cavity. It is demonstrated that the name H. Ducreyi has been used for different groups of bacteria, and that only one of these groups can legitimately be assigned to the genus Haemophilus. Haemolytic V-factor-dependent strains from swine, previously included in H. parahaemolyticus, are significantly different from strains of human origin and should be named H. pleuropneumoniae. None of the strains from swine and fowls were haemin-dependent. The relationships of these strains to the species H. suis and H. gallinarum, and to H. parasuis and H. paragallinarum are discussed. Haemophilus piscium is shown not to belong to the genus Haemophilus. The taxonomic position of H. aphrophilus is uncertain and its possible relationship to Actinobacillus actinomycetemcomitans requires further study. The positive correlation found between the ecology of the strains studied and their affiliation with the different taxa is discussed.
J Gen Microbiol 1976 Mar
PMID:A taxonomic study of the genus Haemophilus, with the proposal of a new species. 77 68

Restriction endonuclease R from Bacillus subtilis strain R cleaves nonmodified SPP 1 DNA in approximately 80, and lambda DNA in about 200 different sites. DNA digests with this endonuclease and with endonuclease Hae III from Haemophilus aegyptius show identical fragmentation patterns on gel electrophoresis, indicating that the two enzymes recognise the same nucleotide sequence. The polynucleotide kinase reaction was used in conjunction with two-dimensional ionophoretic nucleotide mapping methods to identify the 5'-nucleotide sequences at the sites of cleavage by the B. subtilis restriction endonuclease. The results show that the recognition sequence is (see article) where arrows indicate the points of strand scission. Each of the four possible nucleotides can occur in the positions flanking the recognition site.
Mol Gen Genet 1975 Dec 30
PMID:Restriction and modification in B. subtilis. Nucleotide sequence recognised by restriction endonuclease R. Bsu R from strain R. 81 3

A strain of Haemophilus influenzae, called hpm- inhibits the growth of phage HP1c1 but not S2. This inhibition is overcome by HP1c1ph mutants. Phage HP1c1 adsorbs normally to hpm- cells but only a small fraction of infected cells produce phage with a normal burst size or become lysogenic. When hpm- strains lysogenic for HP1c1 are induced, 100 percent of the cells yield phage. There is no degradation of phage DNA after infection of hpm- cells and HP1c1 can normally grow when its DNA is introduced into hpm- by transfection. The most probable explanation is that in hpm- cells the penetration of phage DNA is blocked. The hpm- property behaves as as unstable mutation.
Mol Gen Genet 1975 Aug 05
PMID:An Haemophilus influenzae mutant which inhibits the growth of HP1c1 phage. 108 Aug 31

Vegtative recombination of temperature-sensitive mutants of Haemophilus influezae bacteriophage N3 was measured in wild-type H. influenzae strain Rd9 and in recombination-defective mutants of the Rd strain. Recombinants are formed with low but equal frequency in wild-type cells and recombination-defective mutants of the Rd strain. It is concluded that this phage can carry information in its own genome for vegetative recombination. Lysogenization readily takes place in both strains.
Mol Gen Genet 1976 Aug 10
PMID:Bacteriophage N3 of Haemophilus influenzae. I. Independence of vegetative recombination among Haemophilus influenzae bacteriophage on the host cell. 108 11

Transposon Tn916 was shown to be capable of direct conjugative transfer in broth and membrane matings between strains of Escherichia coli K12 and between E. coli K12 and Haemophilus influenzae type b. Only Tn916 was transferred, but Tn916 donor ability was not itself inheritable by the recipients and seemed to be associated with the presence of Tn916 on a non-conjugative pBR322-derived vector in the original donor strain. Transfer of Tn916 by conjugation was found to be an efficient method for producing insertion mutations in the chromosome of recipient cells. Although such insertions were unstable when the cells were grown under non-selective conditions, it was possible to show that over 40% of the isolated Tn916 insertions in the chromosome of E. coli K12 were in gene(s) concerned with histidine biosynthesis, implying that there is a partial hot-spot for Tn916 insertion on the E. coli K12 chromosome. When a strain of H. influenzae type b was used as a recipient, out of approximately 1500 transconjugants tested, two mutants were isolated with insertions in genes controlling the expression of iron-regulated transferrin-binding proteins. These mutants constitutively produced major 76 kDa and minor 90 kDa proteins which bound transferrin, even when grown under iron-sufficient conditions. Tn916 insertion mutagenesis, following transfer by conjugation, is a convenient method for isolating mutations in genes concerned with iron acquisition by this important human pathogen.
J Gen Microbiol 1992 Mar
PMID:Tn916 insertion mutagenesis in Escherichia coli and Haemophilus influenzae type b following conjugative transfer. 131 5


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