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

A total of 314 strains of Haemophilus, isolated from clinical samples, were studied for the production of beta-galactosidase and beta-xylosidase. None of the H. influenzae strains studied (9 beta-lactamase positive strains and 129 beta-lactamase negative strains) possessed these enzymes. Both enzymes were almost constantly observed among strains of H. paraphrophilus (10 strains studied) and of H. paraphrohaemolyticus (9 strains studied). Among the other species (H. parainfluenzae, 55 strains; H. haemolyticus, 5 strains; H. parahaemolyticus, 97 strains), beta-galactosidase was present in about 30% of the strains studied whereas beta-xylosidase was detected occasionally (3% of the strains studied). Detection of these two enzymes could be a valuable test for the taxonomic study of the genus Haemophilus. However, the type of substrate used for the detection of beta-xylosidase is important: use of the para-nitro-phenyl-beta-xylopyranoside yielded more positive results than the use of its ortho-isomer.
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PMID:Significance of the detection of beta-galactosidase and of beta-xylosidase in the taxonomic study of the genus Haemophilus. 11 91

Twenty-two Haemophilus cultures of types prevalent in swine and of different geographic origins were subjected to biochemical and cultural examinations. Three subgroups were identified: One was unrease-positive, produced porphyrin from delta-aminolevulinic acid, and grew on infusion mediums supplemented only with V factor; the 2nd was unrease-negative, porphyrin-positive, and grew only on serum-enriched mediums with added V factor; and the 3rd was unrease-negative, porphyrin-negative, and grew only on serum-enriched mediums with added V and X factors. The groups generally corresponded to Haemophilus parahaemolyticus, Haemophilus parasuis, and Haemophilus suis, respectively. By means of the unrease and porphyrin tests, it was possible to assign, presumptively, porcine haemophilus cultures to 1 of the 3 species. Other tests, such as beta-galactosidase, hemolysis, and fermentation of carbohydrates were of secondary value in differentiating between these species.
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PMID:Cultural and biochemical criteria for the identification of haemophilus spp from swine. 18 48

Strains of Bisgaard taxon 31, isolated from chickens in South Africa suffering from a respiratory disease with clinical symptoms and gross lesions similar to infectious coryza, showed great phenotypical similarities with Haemophilus paragallinarum infection except for NAD requirement, beta-galactosidase activity and maltose fermentation. Deoxyribonucleic acid-deoxyribonucleic acid hybridization confirmed a high level of genetic relatedness (DNA binding value, 89%) with Haemophilus paragallinarum. Guanine + cytosine content and genome size data also support the classification of taxon 31 strains within the species Haemophilus paragallinarum.
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PMID:Occurrence of V-factor (NAD) independent strains of Haemophilus paragallinarum. 149 9

Possible Haemophilus influenzae colonies in cultures of sputum samples are currently identified by tests for dependence on X and V factors. This method requires further overnight culture and may give a relatively high number of false negative results. Identification of suspected H. influenzae colonies by a 5-min test for production of indole and beta-galactosidase followed by a 1-h porphyrin test was compared with tests for dependence on X and V factors. A commercially produced form of the rapid tests (Haemstrip, Lab M, Bury, Lancs) was used to test 252 potential haemophilus colonies from cultures of sputum samples on heated blood agar. Colonies that were beta-galactosidase-positive after 5 min were considered to be non-H. influenzae and those that were beta-galactosidase-negative but indole-positive were considered to be H. influenzae. At this stage the test had a sensitivity of 99.4% and a specificity of 90.9%. After 1 h, only colonies that were beta-galactosidase- and porphyrin-negative were considered to be H. influenzae, the sensitivity was then 99.5% and the specificity 100%. Similar results were found with colonies from sputum cultures on selective heated blood agar containing bacitracin. The X and V dependence and Haemstrip results were in 97.6% agreement in a double blind test. Of 100 non-haemophilus colonies tested by Haemstrip, two pseudomonads could have been identified as H. influenzae by this method. The high positive predictive value of Haemstrip results depends partly on the initial recognition of potential haemophilus colonies.
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PMID:Provisional identification of Haemophilus influenzae from sputum cultures within 1 h by rapid enzyme tests. 190 45

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)].
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PMID:Phototoxic effects of fluoranthene, a polycyclic aromatic hydrocarbon, on bacterial species. 282 96

The biochemical properties of 39 strains of Haemophilus avium from chickens were determined. All the strains produced acid from fructose, galactose, glucose and mannose but not from lactose. Variable reactions were found for arabinose, maltose, mannitol, sorbitol, trehalose and xylose. No strains showed urease activity or produced indole, while beta-galactosidase and/or ornithine decarboxylase activity was present in some strains. This variability allowed the recognition of 15 biochemical biovars including some not previously recognized in H. avium. Only 25 (64%) of the H. avium strains could be assigned to the three species (Pasteurella avium, P. volantium and Pasteurella species A) recently proposed to replace H. avium.
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PMID:Biochemical properties of catalase-positive avian haemophili. 315 Dec 6

Five tests--satellitism, synthesis of porphyrins, acid production from sucrose, beta-galactosidase activity (ONPG), and indole production--to differentiate between strains of Haemophilus influenzae and strains of V-dependent Haemophilus species were evaluated. Six per cent of strains of H influenzae were misidentified as H parainfluenzae by a test for satellitism using filter paper discs impregnated with X factor, V factor, or both, applied to Columbia Agar. None of seven nutrient agars tested grew Haemophilus species, and determined accurately the X factor requirement. Synthesis of porphyrins from delta-aminolaevulinic acid provided a reliable means of demonstrating that X factor was required. A test for the production of acid from sucrose discriminated successfully between strains of V-dependent Haemophilus species (positive) and H influenzae (negative). Most isolates were identified correctly by the ONPG test, but occasional V-dependent strains were negative and could be misidentified as H influenzae. The discriminative value of the indole test was unsatisfactorily low. The results of the tests are discussed in relation to the identification of H influenzae in the diagnostic laboratory.
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PMID:Evaluation of some methods for the laboratory identification of Haemophilus influenzae. 641 74

The API ZYM system (Analytab Products, Plainview, N.Y.), containing 19 chromogenic substrates, was utilized semiquantitatively to detect extracellular acid and alkaline phosphatases, aminopeptidases, proteases, esterase-lipase, phosphoamidase, and glycosidases in 128 oral and nonoral isolates of black-pigmented Bacteroides, Actinobacillus, Haemophilus aphrophilus, Capnocytophaga, Fusobacterium nucleatum, Wolinella recta, and Veillonella parvula. In the black-pigmented Bacteroides group of organisms, a strong trypsin reaction was present in Bacteroides gingivalis (oral species) but not in Bacteroides asaccharolyticus (nonoral species). Bacteroides melaninogenicus subsp. melaninogenicus, in contrast to Bacteroides melaninogenicus subsp. intermedius, exhibited strong N-acetyl-beta-glucosaminidase activity. H. aphrophilus produced beta-galactosidase and alpha-glucosidase, but the closely related Actinobacillus actinomycetemcomitans did not. Capnocytophaga was distinct with respect to strong aminopeptidase reactions. This study showed that a wide range of enzymes which have the potential of causing tissue injury and inflammation can be elaborated from major oral gram-negative species. Also, the API ZYM system appears to be a valuable adjunct to traditional biochemical testing in identifying oral gram-negative species.
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PMID:Enzymatic characterization of some oral and nonoral gram-negative bacteria with the API ZYM system. 702 98

DNA sequencing, RNA mapping, and protein expression experiments revealed the presence of a gene, tfoX+, encoding a 24.9-kDa polypeptide, that is transcribed divergently from a common promoter region with the Haemophilus influenzae rec-1+ gene. H. influenzae strains mutant for tfoX failed to bind transforming DNA and were transformation deficient. Primer extension experiments utilizing in vivo total RNA from precompetent and competent H. influenzae cells demonstrated that transcription of tfoX+ increased immediately upon competence induction, suggesting that tfoX+ is an early competence gene. Similar experiments showed that the expression of the late competence-specific gene, com101A+, was tfoX+ dependent. Moreover, expression of plasmid-borne tfoX+ in H. influenzae resulted in constitutive competence. The addition of cyclic adenosine monophosphate (cAMP) to strains carrying a tfoX::lacZ operon fusion resulted in an immediate increase in beta-galactosidase activity that correlated with an increase in genetic transformability. Collectively, our results suggest that TfoX may play a key role in the development of genetic competence by regulating the expression of late competence-specific genes.
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PMID:Identification of a DNA transformation gene required for com101A+ expression and supertransformer phenotype in Haemophilus influenzae. 772 7

The 2'-N-acetyltransferase [AAC(2')-Ia] in Providencia stuartii has a dual function where it is involved in the acetylation of peptidoglycan and certain aminoglycosides. A search for negative regulators of the aac(2')-Ia gene has resulted in the identification of aarC. A missense allele (aarC1) resulted in an 8.9-fold increase in beta-galactosidase accumulation from an aac(2')-lacZ transcriptional fusion. Northern blot analysis demonstrated an increase in aac(2')-Ia mRNA accumulation that was specific to cells at high density. In addition, the aarC1 allele also resulted in a substantial increase in the expression of aarP, a transcriptional activator of the aac(2')-Ia gene. The wild-type aarC gene was isolated by complementation and encodes a predicted protein of 365 amino acids with a molecular mass of 39,815 Da. The predicted AarC protein exhibited 88% amino acid homology to the previously identified GcpE protein of Escherichia coli and 86% homology to a gene product from Haemophilus influenzae. The E. coli gcpE gene was able to functionally complement the aarC1 allele in P. stuartii. The aarC1 allele was identified as a T to G transversion that resulted in a valine to glycine substitution at position 136 in the AarC protein. The aarC gene appears to be essential for cell viability as construction of a disrupted copy (aarC::lacZ) was possible only in cells that carried an episomal copy of aarC or gcpE.
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PMID:aarC, an essential gene involved in density-dependent regulation of the 2'-N-acetyltransferase in Providencia stuartii. 907 12


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