Acid Resistance - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

Acid Resistance

The Experts below are selected from a list of 209874 Experts worldwide ranked by ideXlab platform

Acid Resistance – Free Register to Access Experts & Abstracts

Akio Kuroda – One of the best experts on this subject based on the ideXlab platform.

  • The Silicon Layer Supports Acid Resistance of Bacillus cereus Spores
    Journal of bacteriology, 2009
    Co-Authors: Ryuichi Hirota, Yumehiro Hata, Takeshi Ikeda, Takenori Ishida, Akio Kuroda
    Abstract:

    Silicon (Si) is considered to be a “quasiessential” element for most living organisms. However, silicate uptake in bacteria and its physiological functions have remained obscure. We observed that Si is deposited in a spore coat layer of nanometer-sized particles in Bacillus cereus and that the Si layer enhances Acid Resistance. The novel Acid Resistance of the spore mediated by Si encapsulation was also observed in other Bacillus strains, representing a general adaptation enhancing survival under Acidic conditions.

Jian Zhou – One of the best experts on this subject based on the ideXlab platform.

  • HF/HCl Acid Resistance mechanisms of alumina ceramics in the Al2O3-MgO-CaO-SiO2-Y2O3 system
    Ceramics International, 2019
    Co-Authors: Jian Zhou
    Abstract:

    Abstract Silicon compounds in raw materials are the main reason for the low HF/HCl Acid Resistance of alumina ceramics. Y2O3 can improve the Acid Resistance of alumina ceramics. This work aimed to reveal the mechanisms of the effects of Y2O3 on the form of Si and the durability of the ceramic. An experiment on a high-temperature reaction between Y3Al5O12 and a polycrystalline alumina ceramic was designed. The effect of corrosion time on the Acid solubility of the alumina ceramic was investigated. The results show that Si can dissolve in Y3Al5O12 to generate solid solutions, impeding the generation of Si-containing compounds with bad Acid Resistance, and decreasing the content of amorphous Si. The Acid solubility of the ceramic was only 0.95%, even when the corrosion time was extended to 60 times the industry standard. This revelation of the Acid Resistance mechanisms can provide a new idea for designing corrosion-resistant ceramics.

  • Effect of Y2O3 on Acid Resistance of alumina ceramic
    Ceramics International, 2017
    Co-Authors: Jian Zhou
    Abstract:

    Abstract This work aimed to improve the Acid Resistance of an alumina ceramic. Acid corrosion of alumina ceramic composed of Al 2 O 3 -CaCO 3 -SiO 2 -MgO-Y 2 O 3 (ACSMY) was investigated in a hydrochloric-hydrofluoric Acid solution at 65 °C for 30 min. The effect of Y 2 O 3 content on sintering temperature, density, and Acid solubility were discussed. The composition and microstructure of this material were analyzed. The Acid solubilities of minor crystal phases (Y 3 Al 5 O 12 , CaAl 12 O 19 , Ca 2 Al 2 SiO 7 , and CaAl 2 Si 2 O 8 ) and the effect of them on Acid Resistance of this alumina ceramic were studied. The results showed that Y 2 O 3 additive can enhance density and change the type of phases. Phases with good Acid Resistance and dense structure lead to a crust formed on the surface of ceramic during Acid corrosion. The crust can effectively protect the interior structure of the sample from Acid solution, and then improve the Acid Resistance of the material.

  • Effect of Sc2O3 on the Acid Resistance of alumina ceramic
    Materials Letters, 2016
    Co-Authors: Jian Zhou
    Abstract:

    Abstract A ceramic proppant was created in an Al 2 O 3 -CaO-MgO-SiO 2 -Sc 2 O 3 (ACMSS) system to increase Acid Resistance. The impacts of corrosion on the properties of proppants were investigated using a 12 wt% HCl +3 wt% HF Acid mixture. The microstructure and phase of samples were analyzed. The Acid Resistance of silicon-containing alumina ceramic can be effectively improved by adding Sc 2 O 3 . The results show that the Acid solubility of sample added a small amount of Sc 2 O 3 can be as low as 0.307%. The corrosion Resistance mechanism of this ceramic material is revealed.

Ryuichi Hirota – One of the best experts on this subject based on the ideXlab platform.

  • The Silicon Layer Supports Acid Resistance of Bacillus cereus Spores
    Journal of bacteriology, 2009
    Co-Authors: Ryuichi Hirota, Yumehiro Hata, Takeshi Ikeda, Takenori Ishida, Akio Kuroda
    Abstract:

    Silicon (Si) is considered to be a “quasiessential” element for most living organisms. However, silicate uptake in bacteria and its physiological functions have remained obscure. We observed that Si is deposited in a spore coat layer of nanometer-sized particles in Bacillus cereus and that the Si layer enhances Acid Resistance. The novel Acid Resistance of the spore mediated by Si encapsulation was also observed in other Bacillus strains, representing a general adaptation enhancing survival under Acidic conditions.

John W. Foster – One of the best experts on this subject based on the ideXlab platform.

  • Escherichia coli Acid Resistance: tales of an amateur Acidophile
    Nature Reviews Microbiology, 2004
    Co-Authors: John W. Foster
    Abstract:

    There are four known AcidResistance systems present in pathogenic and non-pathogenic strains of Escherichia coli . The two most effective systems involve the decarboxylation of glutamate or arginine, a process that consumes an intracellular proton. In combination with cognate amino Acid antiporters, the amino-Acid-dependent systems increase intracellular pH and reverse transmembrane potential. Cl^−/H^+ antiporters are also important in this process. Genetic regulation of the glutamate-dependent AcidResistance system involves a complex regulatory network of at least 10 proteins that mediate induction of gadE , the direct activator of the glutamate decarboxylase and antiporter genes. Glutamate-dependent Acid Resistance seems to be important for the survival of E. coli O157:H7 in the bovine gastrointestinal tract. Gastrointestinal pathogens are faced with an extremely Acidic environment. Within moments, a pathogen such as Escherichia coli O157:H7 can move from the nurturing pH 7 environment of a hamburger to the harsh pH 2 milieu of the stomach. Surprisingly, certain microorganisms that grow at neutral pH have elegantly regulated systems that enable survival during excursions into Acidic environments. The best-characterized AcidResistance system is found in E. coli .

  • escherichia coli Acid Resistance tales of an amateur Acidophile
    Nature Reviews Microbiology, 2004
    Co-Authors: John W. Foster
    Abstract:

    Gastrointestinal pathogens are faced with an extremely Acidic environment. Within moments, a pathogen such as Escherichia coli O157:H7 can move from the nurturing pH 7 environment of a hamburger to the harsh pH 2 milieu of the stomach. Surprisingly, certain microorganisms that grow at neutral pH have elegantly regulated systems that enable survival during excursions into Acidic environments. The best-characterized AcidResistance system is found in E. coli.

  • Acid Resistance in Escherichia coli.
    Advances in applied microbiology, 2003
    Co-Authors: Hope Richard, John W. Foster
    Abstract:

    To colonize and cause disease, enteric pathogens must overcome environmental challenges that include Acid stress in the host’s stomach as well as short-chain fatty Acid stress in the intestine of the host and reservoir. Three known inducible systems have evolved for stationary phase Acid Resistance in E. coli. These systems each provide a different level of protection with different requirements and induction conditions. Acid Resistance system 1 (AR1) is Acid induced in stationary phase, requires the presence of RpoS, and provides the least level of protection at pH 2.5. Acid Resistance system 2 (AR2) is glutamate dependent and stationary phase induced, requires the presence of glutamate decarboxylase and a putative glutamate:GABA antiporter, and provides the highest level of protection. Acid Resistance system 3 (AR3) is arginine dependent and Acid induced under anaerobic conditions, requires the presence of arginine decarboxylase (AdiA), and provides only a modest level of protection. These three systems along with log phase Acid tolerance protect cells from the Acid stresses in both the reservoir and host, which can range from pH 2 to 4.5. They also protect against Acid stress involved in food processing and facilitate the low infectious dose characteristic of E. coli, significantly contributing to the pathogenesis of this organism.

Michael G Ganzle – One of the best experts on this subject based on the ideXlab platform.

  • glutamine glutamate and arginine based Acid Resistance in lactobacillus reuteri
    Food Microbiology, 2014
    Co-Authors: Januana S Teixeira, Arisha Seeras, Alma Fernanda Sanchezmaldonado, Chonggang Zhang, Marcia Shuwei Su, Michael G Ganzle
    Abstract:

    This study aimed to determine whether glutamine deamidation improves Acid Resistance of Lactobacillus reuteri, and to assess whether arginine, glutamine, and glutamate-mediated Acid Resistance are redundant or complementary mechanisms of Acid Resistance. Three putative glutaminase genes, gls1, gls2, and gls3, were identified in L. reuteri 100-23. All three genes were expressed during growth in mMRS and wheat sourdough. L. reuteri consistently over-expressed gls3 and the glutamate decarboxylase gadB. L. reuteri 100-23ΔgadB over-expressed gls3 and the arginine deiminase gene adi. Analysis of the survival of L. reuteri in Acidic conditions revealed that arginine conversion is effective at pH of 3.5 while glutamine or glutamate conversion were effective at pH of 2.5. Arginine conversion increased the pHin but not ΔΨ; glutamate decarboxylation had only a minor effect on the pHin but increased the ΔΨ. This study demonstrates that glutamine deamidation increases the Acid Resistance of L. reuteri independent of glutamate decarboxylase activity. Arginine and glutamine/glutamate conversions confer Resistance to lactate at pH of 3.5 and phosphate at pH of 2.5, respectively. Knowledge of L. reuteri’s Acid Resistance improves the understanding of the adaptation of L. reuteri to intestinal ecosystems, and facilitates the selection of probiotic and starter cultures.

  • contribution of glutamate decarboxylase in lactobacillus reuteri to Acid Resistance and persistence in sourdough fermentation
    Microbial Cell Factories, 2011
    Co-Authors: Sabine Schlicht, Michael G Ganzle
    Abstract:

    Background Acid stress impacts the persistence of lactobacilli in industrial sourdough fermentations, and in intestinal ecosystems. However, the contribution of glutamate to Acid Resistance in lactobacilli has not been demonstrated experimentally, and evidence for the contribution of Acid Resistance to the competitiveness of lactobacilli in sourdough is lacking. It was therefore the aim of this study to investigate the ecological role of glutamate decarboxylase in L. reuteri.