The Experts below are selected from a list of 783 Experts worldwide ranked by ideXlab platform

Rodney A. Moxley - One of the best experts on this subject based on the ideXlab platform.

  • Glucose significantly enhances enterotoxigenic Escherichia coli adherence to intestinal epithelial cells through its effects on heat-labile enterotoxin production. PLoS One 9:e113230. doi
    2016
    Co-Authors: Prageeth Wijemanne, Rodney A. Moxley
    Abstract:

    The present study tested whether exposure of enterotoxigenic Escherichia coli (ETEC) to glucose at different concentrations in the media results in increased bacterial adherence to host cells through increased heat-labile enterotoxin (LT) production, thereby suggesting the effects are physiological. Porcine-origin ETEC strains grown in Casamino Acid yeast extract medium containing different concentrations of glucose were washed and inoculated onto IPEC-J2 porcine intestinal epithelial cells to test for effects on adherence and host cell cAMP concentrations. Consistent with previous studies, all LT+ strains had higher ETEC adherence to IPEC-J2 cells than did LT2 strains. Adherence of the LT2 but not the LT+ strains was increased by pre-incubating the IPEC-J2 cells with LT and decreased by co-incubation with GM1 ganglioside in a dose-dependent manner (P,0.05). To determine whether the glucose concentration of the cell culture media has an effect on adherence, IPEC-J2 cells were inoculated with LT+ or LT2 strains in cell culture media containing a final glucose concentration of 0, 0.25, 0.5, 1.0 or 2.0%, and incubated for 4 h. Only media containing 0.25 % glucose resulted in increased adherence and cAMP levels, and this was limited to IPEC-J2 cells inoculated with LT+ strains. This study supports the hypothesis that glucose, at a concentration optimal for LT expression, enhances bacterial adherence through the promotion of LT production. Hence, these results establish the physiological relevance of the effects of glucose on LT production and provide a basis for ho

  • glucose significantly enhances enterotoxigenic escherichia coli adherence to intestinal epithelial cells through its effects on heat labile enterotoxin production
    PLOS ONE, 2014
    Co-Authors: Prageeth Wijemanne, Rodney A. Moxley
    Abstract:

    The present study tested whether exposure of enterotoxigenic Escherichia coli (ETEC) to glucose at different concentrations in the media results in increased bacterial adherence to host cells through increased heat-labile enterotoxin (LT) production, thereby suggesting the effects are physiological. Porcine-origin ETEC strains grown in Casamino Acid yeast extract medium containing different concentrations of glucose were washed and inoculated onto IPEC-J2 porcine intestinal epithelial cells to test for effects on adherence and host cell cAMP concentrations. Consistent with previous studies, all LT+ strains had higher ETEC adherence to IPEC-J2 cells than did LT− strains. Adherence of the LT− but not the LT+ strains was increased by pre-incubating the IPEC-J2 cells with LT and decreased by co-incubation with GM1 ganglioside in a dose-dependent manner (P<0.05). To determine whether the glucose concentration of the cell culture media has an effect on adherence, IPEC-J2 cells were inoculated with LT+ or LT− strains in cell culture media containing a final glucose concentration of 0, 0.25, 0.5, 1.0 or 2.0%, and incubated for 4 h. Only media containing 0.25% glucose resulted in increased adherence and cAMP levels, and this was limited to IPEC-J2 cells inoculated with LT+ strains. This study supports the hypothesis that glucose, at a concentration optimal for LT expression, enhances bacterial adherence through the promotion of LT production. Hence, these results establish the physiological relevance of the effects of glucose on LT production and provide a basis for how glucose intake may influence the severity of ETEC infection.

Prageeth Wijemanne - One of the best experts on this subject based on the ideXlab platform.

  • Glucose significantly enhances enterotoxigenic Escherichia coli adherence to intestinal epithelial cells through its effects on heat-labile enterotoxin production. PLoS One 9:e113230. doi
    2016
    Co-Authors: Prageeth Wijemanne, Rodney A. Moxley
    Abstract:

    The present study tested whether exposure of enterotoxigenic Escherichia coli (ETEC) to glucose at different concentrations in the media results in increased bacterial adherence to host cells through increased heat-labile enterotoxin (LT) production, thereby suggesting the effects are physiological. Porcine-origin ETEC strains grown in Casamino Acid yeast extract medium containing different concentrations of glucose were washed and inoculated onto IPEC-J2 porcine intestinal epithelial cells to test for effects on adherence and host cell cAMP concentrations. Consistent with previous studies, all LT+ strains had higher ETEC adherence to IPEC-J2 cells than did LT2 strains. Adherence of the LT2 but not the LT+ strains was increased by pre-incubating the IPEC-J2 cells with LT and decreased by co-incubation with GM1 ganglioside in a dose-dependent manner (P,0.05). To determine whether the glucose concentration of the cell culture media has an effect on adherence, IPEC-J2 cells were inoculated with LT+ or LT2 strains in cell culture media containing a final glucose concentration of 0, 0.25, 0.5, 1.0 or 2.0%, and incubated for 4 h. Only media containing 0.25 % glucose resulted in increased adherence and cAMP levels, and this was limited to IPEC-J2 cells inoculated with LT+ strains. This study supports the hypothesis that glucose, at a concentration optimal for LT expression, enhances bacterial adherence through the promotion of LT production. Hence, these results establish the physiological relevance of the effects of glucose on LT production and provide a basis for ho

  • glucose significantly enhances enterotoxigenic escherichia coli adherence to intestinal epithelial cells through its effects on heat labile enterotoxin production
    PLOS ONE, 2014
    Co-Authors: Prageeth Wijemanne, Rodney A. Moxley
    Abstract:

    The present study tested whether exposure of enterotoxigenic Escherichia coli (ETEC) to glucose at different concentrations in the media results in increased bacterial adherence to host cells through increased heat-labile enterotoxin (LT) production, thereby suggesting the effects are physiological. Porcine-origin ETEC strains grown in Casamino Acid yeast extract medium containing different concentrations of glucose were washed and inoculated onto IPEC-J2 porcine intestinal epithelial cells to test for effects on adherence and host cell cAMP concentrations. Consistent with previous studies, all LT+ strains had higher ETEC adherence to IPEC-J2 cells than did LT− strains. Adherence of the LT− but not the LT+ strains was increased by pre-incubating the IPEC-J2 cells with LT and decreased by co-incubation with GM1 ganglioside in a dose-dependent manner (P<0.05). To determine whether the glucose concentration of the cell culture media has an effect on adherence, IPEC-J2 cells were inoculated with LT+ or LT− strains in cell culture media containing a final glucose concentration of 0, 0.25, 0.5, 1.0 or 2.0%, and incubated for 4 h. Only media containing 0.25% glucose resulted in increased adherence and cAMP levels, and this was limited to IPEC-J2 cells inoculated with LT+ strains. This study supports the hypothesis that glucose, at a concentration optimal for LT expression, enhances bacterial adherence through the promotion of LT production. Hence, these results establish the physiological relevance of the effects of glucose on LT production and provide a basis for how glucose intake may influence the severity of ETEC infection.

Mark A Jackson - One of the best experts on this subject based on the ideXlab platform.

  • Impact of carbon and nitrogen nutrition on the quality, yield and composition of blastospores of the bioinsecticidal fungus Paecilomyces fumosoroseus
    Journal of Industrial Microbiology and Biotechnology, 2005
    Co-Authors: Sophie Cliquet, Mark A Jackson
    Abstract:

    The impact of growing cultures of Paecilomyces fumosoroseus in liquid media containing four combinations of glucose and Casamino Acids (8 g l^−1 or 80 g l^−1 glucose, 1.32 g l^−1 or 13.2 g l^−1 Casamino Acids) was evaluated, based on blastospore production, germination rate, viability after freeze-drying and short-term storage stability. When blastospores were produced using a high Casamino Acid concentration, blastospore yields and germination rates were significantly higher (13.2–18.5×10^7 blastospores ml^−1, 50–60% germination after 4 h), compared to cultures grown in media containing lower Casamino Acid concentrations (0.4–2.3×10^7 blastospores ml^−1, 10–20% germination after 4 h). Chemical analyses of blastospore composition showed that accelerated blastospore germination may be related to increased proteinaceous reserves rather than to glycogen or lipid accumulation. Tolerance to freeze-drying by blastospores suspended in spent medium was enhanced by a high initial Casamino Acid concentration in the culture medium (75% survival) and by the residual glucose concentrations in the spent medium. Under the conditions of this study, the storage stability of blastospores of P. fumosoroseus was unaffected by the nutritional condition in which they were produced.

  • liquid culture production of desiccation tolerant blastospores of the bioinsecticidal fungus paecilomyces fumosoroseus
    Fungal Biology, 1997
    Co-Authors: Mark A Jackson, Michael R Mcguire, Lawrence A Lacey, Stephen P Wraight
    Abstract:

    Liquid media with differing carbon concentrations and carbon-to-nitrogen ratios were tested for production of desiccation tolerant blastospores of Paecilomyces fumosoroseus. While all media tested supported sporulation in submerged culture, high blastospore concentrations (5·8 × 108) spores ml−) were produced in media containing 80 g glucose l− and 13·2 g Casamino Acids l− (MS medium) and a significantly higher percentage (79%) of these blastospores survived air drying. Media containing glucose concentrations greater than 20 g l − and Casamino Acid concentrations between 13·2 and 40 g l− supported maximal production of desiccation tolerant blastospores. All 23 isolates of P. fumosoroseus grown in MS media produced high concentrations of desiccation tolerant blastospores. When stored at 4 °C, more than 60% of the lyophilized blastospores produced in MS medium were still viable after 7 months storage while less than 25% of the air-dried blastospores survived after 90 d storage. Standard whitefly bioassays were performed to compare air-dried blastospores of P. fumosoroseus ARSEF 4491 with solid substrate-produced conidia of Beauveria bassiana ARSEF 252. Air-dried blastospores of P. fumosoroseus gave LD50s of 60 and 113 blastospores mm− for the silverleaf whitefly (Bemisia argentifolii) in two separate bioassays with potency ratios (LD50 B. bassiana/LD50 P. fumosoroseus)of 3·9 and 3·8, respectively. These results have demonstrated that high concentrations of blastospores of P. fumosoroseus can be rapidly produced in liquid culture, remain viable following drying, and infect and kill silverleaf whitefly.

Hari Sharan Karki - One of the best experts on this subject based on the ideXlab platform.

  • Diversities in Virulence, Antifungal Activity, Pigmentation and DNA Fingerprint among Strains of
    2016
    Co-Authors: Burkholderia Glumae, Rebecca A Melanson, M C Rush, Donald E Groth, Inderjit K. Barphagha, Hari Sharan Karki, Bishnu K Shrestha, Jae Woo Han, Beom Seok Kim, Jong Hyun Ham
    Abstract:

    Burkholderia glumae is the primary causal agent of bacterial panicle blight of rice. In this study, 11 naturally avirulent and nine virulent strains of B. glumae native to the southern United States were characterized in terms of virulence in rice and onion, toxofalvin production, antifungal activity, pigmentation and genomic structure. Virulence of B. glumae strains on rice panicles was highly correlated to virulence on onion bulb scales, suggesting that onion bulb can be a convenient alternative host system to efficiently determine the virulence of B. glumae strains. Production of toxoflavin, the phytotoxin that functions as a major virulence factor, was closely associated with the virulence phenotypes of B. glumae strains in rice. Some strains of B. glumae showed various levels of antifungal activity against Rhizoctonia solani, the causal agent of sheath blight, and pigmentation phenotypes on Casamino Acid-peptone-glucose (CPG) agar plates regardless of their virulence traits. Purple and yellow-green pigments were partially purified from a pigmenting strain of B. glumae, 411gr-6, and the purple pigment fraction showed a strong antifungal activity against Collectotrichum orbiculare. Genetic variations were detected among the B. glumae strains from DNA fingerprinting analyses by repetitive element sequence-based PCR (rep-PCR) for BOX-A1R-based repetitive extragenic palindromic (BOX) or enterobacterial repetitive intergenic consensus (ERIC) sequences of bacteria; and close genetic relatedness among virulent but pigment-deficient strains were revealed by clustering analyse

  • diversities in virulence antifungal activity pigmentation and dna fingerprint among strains of burkholderia glumae
    PLOS ONE, 2012
    Co-Authors: Hari Sharan Karki, M C Rush, Donald E Groth, Inderjit K. Barphagha, Bishnu K Shrestha, Rebecca A Melanson
    Abstract:

    Burkholderia glumae is the primary causal agent of bacterial panicle blight of rice. In this study, 11 naturally avirulent and nine virulent strains of B. glumae native to the southern United States were characterized in terms of virulence in rice and onion, toxofalvin production, antifungal activity, pigmentation and genomic structure. Virulence of B. glumae strains on rice panicles was highly correlated to virulence on onion bulb scales, suggesting that onion bulb can be a convenient alternative host system to efficiently determine the virulence of B. glumae strains. Production of toxoflavin, the phytotoxin that functions as a major virulence factor, was closely associated with the virulence phenotypes of B. glumae strains in rice. Some strains of B. glumae showed various levels of antifungal activity against Rhizoctonia solani, the causal agent of sheath blight, and pigmentation phenotypes on Casamino Acid-peptone-glucose (CPG) agar plates regardless of their virulence traits. Purple and yellow-green pigments were partially purified from a pigmenting strain of B. glumae, 411gr-6, and the purple pigment fraction showed a strong antifungal activity against Collectotrichum orbiculare. Genetic variations were detected among the B. glumae strains from DNA fingerprinting analyses by repetitive element sequence-based PCR (rep-PCR) for BOX-A1R-based repetitive extragenic palindromic (BOX) or enterobacterial repetitive intergenic consensus (ERIC) sequences of bacteria; and close genetic relatedness among virulent but pigment-deficient strains were revealed by clustering analyses of DNA fingerprints from BOX-and ERIC-PCR.

  • a conserved two component regulatory system pids pidr globally regulates pigmentation and virulence related phenotypes of burkholderia glumae
    Molecular Plant Pathology, 2012
    Co-Authors: Hari Sharan Karki, Inderjit K. Barphagha
    Abstract:

    SUMMARY Burkholderia glumae is a rice pathogenic bacterium that causes bacterial panicle blight. Some strains of this pathogen produce dark brown pigments when grown on Casamino-Acid peptone glucose (CPG) agar medium. A pigment-positive and highly virulent strain of B. glumae, 411gr-6, was randomly mutagenized with mini-Tn5gus, and the resulting mini-Tn5gus derivatives showing altered pigmentation phenotypes were screened on CPG agar plates to identify the genetic elements governing the pigmentation of B. glumae. In this study, a novel two-component regulatory system (TCRS) composed of the PidS sensor histidine kinase and the PidR response regulator was identified as an essential regulatory factor for pigmentation. Notably, the PidS/PidR TCRS was also required for the elicitation of the hypersensitive response on tobacco leaves, indicating the dependence of the hypersensitive response and pathogenicity (Hrp) type III secretion system of B. glumae on this regulatory factor. In addition, B. glumae mutants defective in the PidS/PidR TCRS showed less production of the phytotoxin, toxoflavin, and less virulence on rice panicles and onion bulbs relative to the parental strain, 411gr-6. The presence of highly homologous PidS and PidR orthologues in other Burkholderia species suggests that PidS/PidR-family TCRSs may exert the same or similar functions in different Burkholderia species, including both plant and animal pathogens.

Inderjit K. Barphagha - One of the best experts on this subject based on the ideXlab platform.

  • Diversities in Virulence, Antifungal Activity, Pigmentation and DNA Fingerprint among Strains of
    2016
    Co-Authors: Burkholderia Glumae, Rebecca A Melanson, M C Rush, Donald E Groth, Inderjit K. Barphagha, Hari Sharan Karki, Bishnu K Shrestha, Jae Woo Han, Beom Seok Kim, Jong Hyun Ham
    Abstract:

    Burkholderia glumae is the primary causal agent of bacterial panicle blight of rice. In this study, 11 naturally avirulent and nine virulent strains of B. glumae native to the southern United States were characterized in terms of virulence in rice and onion, toxofalvin production, antifungal activity, pigmentation and genomic structure. Virulence of B. glumae strains on rice panicles was highly correlated to virulence on onion bulb scales, suggesting that onion bulb can be a convenient alternative host system to efficiently determine the virulence of B. glumae strains. Production of toxoflavin, the phytotoxin that functions as a major virulence factor, was closely associated with the virulence phenotypes of B. glumae strains in rice. Some strains of B. glumae showed various levels of antifungal activity against Rhizoctonia solani, the causal agent of sheath blight, and pigmentation phenotypes on Casamino Acid-peptone-glucose (CPG) agar plates regardless of their virulence traits. Purple and yellow-green pigments were partially purified from a pigmenting strain of B. glumae, 411gr-6, and the purple pigment fraction showed a strong antifungal activity against Collectotrichum orbiculare. Genetic variations were detected among the B. glumae strains from DNA fingerprinting analyses by repetitive element sequence-based PCR (rep-PCR) for BOX-A1R-based repetitive extragenic palindromic (BOX) or enterobacterial repetitive intergenic consensus (ERIC) sequences of bacteria; and close genetic relatedness among virulent but pigment-deficient strains were revealed by clustering analyse

  • diversities in virulence antifungal activity pigmentation and dna fingerprint among strains of burkholderia glumae
    PLOS ONE, 2012
    Co-Authors: Hari Sharan Karki, M C Rush, Donald E Groth, Inderjit K. Barphagha, Bishnu K Shrestha, Rebecca A Melanson
    Abstract:

    Burkholderia glumae is the primary causal agent of bacterial panicle blight of rice. In this study, 11 naturally avirulent and nine virulent strains of B. glumae native to the southern United States were characterized in terms of virulence in rice and onion, toxofalvin production, antifungal activity, pigmentation and genomic structure. Virulence of B. glumae strains on rice panicles was highly correlated to virulence on onion bulb scales, suggesting that onion bulb can be a convenient alternative host system to efficiently determine the virulence of B. glumae strains. Production of toxoflavin, the phytotoxin that functions as a major virulence factor, was closely associated with the virulence phenotypes of B. glumae strains in rice. Some strains of B. glumae showed various levels of antifungal activity against Rhizoctonia solani, the causal agent of sheath blight, and pigmentation phenotypes on Casamino Acid-peptone-glucose (CPG) agar plates regardless of their virulence traits. Purple and yellow-green pigments were partially purified from a pigmenting strain of B. glumae, 411gr-6, and the purple pigment fraction showed a strong antifungal activity against Collectotrichum orbiculare. Genetic variations were detected among the B. glumae strains from DNA fingerprinting analyses by repetitive element sequence-based PCR (rep-PCR) for BOX-A1R-based repetitive extragenic palindromic (BOX) or enterobacterial repetitive intergenic consensus (ERIC) sequences of bacteria; and close genetic relatedness among virulent but pigment-deficient strains were revealed by clustering analyses of DNA fingerprints from BOX-and ERIC-PCR.

  • a conserved two component regulatory system pids pidr globally regulates pigmentation and virulence related phenotypes of burkholderia glumae
    Molecular Plant Pathology, 2012
    Co-Authors: Hari Sharan Karki, Inderjit K. Barphagha
    Abstract:

    SUMMARY Burkholderia glumae is a rice pathogenic bacterium that causes bacterial panicle blight. Some strains of this pathogen produce dark brown pigments when grown on Casamino-Acid peptone glucose (CPG) agar medium. A pigment-positive and highly virulent strain of B. glumae, 411gr-6, was randomly mutagenized with mini-Tn5gus, and the resulting mini-Tn5gus derivatives showing altered pigmentation phenotypes were screened on CPG agar plates to identify the genetic elements governing the pigmentation of B. glumae. In this study, a novel two-component regulatory system (TCRS) composed of the PidS sensor histidine kinase and the PidR response regulator was identified as an essential regulatory factor for pigmentation. Notably, the PidS/PidR TCRS was also required for the elicitation of the hypersensitive response on tobacco leaves, indicating the dependence of the hypersensitive response and pathogenicity (Hrp) type III secretion system of B. glumae on this regulatory factor. In addition, B. glumae mutants defective in the PidS/PidR TCRS showed less production of the phytotoxin, toxoflavin, and less virulence on rice panicles and onion bulbs relative to the parental strain, 411gr-6. The presence of highly homologous PidS and PidR orthologues in other Burkholderia species suggests that PidS/PidR-family TCRSs may exert the same or similar functions in different Burkholderia species, including both plant and animal pathogens.