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Showing 1 to 20 of 27 for “"acid resistance"”.
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Acid resistance of sewer pipe concrete
… in which biogenically generated sulphuric acid attacks the concrete and lowers its structural integrity. The Virginia Experimental Sewer is a ‘live sewer’ in South Africa for investigating acid resistance of concrete made with different cement/aggregate combinations...
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Acid resistance of sewer pipe concrete
A hydrochloric acid solution laboratory test was developed to assess the resistance of concrete used in the manufacture of pipes to sulphuric acid environments encountered in sewers. A hydrochloric acid solution (pH of 1,00) simulates the attack on concrete sewer pipes at the average daily sewage …
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Mechanistic characterization of acetic acid resistance enzymes of Acetobacer aceti
… (<em>A. aceti</em>) is a Gram-negative, acidophilic bacterium that is used for the industrial production of acetic acid from ethanol. Oxidation of ethanol by membrane-bound oxidoreductases provides energy for A. aceti and the production of high concentrations of acetic acid is an …
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Identification and characterization of farR and farE as a regulator and effector of fatty acid resistance in Staphylococcus aureus
… aureus is exposed to antimicrobial fatty acids on the skin, in nasal secretions and in abscesses, specific mechanisms for regulating gene expression and intrinsic resistance in response to these fatty acids have not been reported. Through in vitro selection for increased resistance of S. …
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Elucidation of weak organic acid resistance mechanisms in non-Saccharomyces yeast: a case study of Zygosaccharomyces parabailii and Kluyveromyces marxianus
… including bulk chemicals such as organic acids. However, efficient and economically viable production of organic acids has to face problems related to low productivity/titer and toxicity of the final product. Therefore, the exploration of yeast biodiversity to exploit unique native …
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A Specialized Citric Acid Cycle Requiring Succinyl-Coenzyme A (CoA):Acetate CoA-Transferase (AarC) Confers Acetic Acid Resistance on the Acidophile Acetobacter aceti
The characteristic ability of acetic acid bacteria to aerobically oxidize ethanol to acetic acid has been harnessed for millennia to produce vinegar. Acetic acid permeates cell membranes at low pH and generally inhibits bacterial growth at low millimolar concentrations. The strains used for vinegar …
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Relative fluoride response of caries lesions created in fluorotic and sound teeth studied underremineralizing conditions
… formation, and b) To investigate the acquired acid resistance of pH-cycled lesions relative to their fluorosis severity. Materials and Methods: Three hundred sixty (360) extracted human molars (sound and fluorosed) were collected and divided into four main groups based on their TF score (0; 1; …
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The Functional Characterization of QSEC a Bacterial Adrenergic Receptor and the LuxR Homologue SDIA in EHEC
… reports have indicated that glutamate-dependent acid resistance (AR2) is required for EHEC to survive in cattle. qPCR comparing WT EHEC to ΔsdiA showed a decreased expression of AR2 genes. When AHL was added to WT EHEC an increase was seen in AR2 gene expression. This effect was absent in ΔsdiA. …
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Acid adaptation of Escherichia coli O157:H7 in fermented goat milk
… study was undertaken to determine the effect of acid adaptation on the survival and growth of Escherichia coli in broth and fermented goat milk. In the first phase of the study, acid resistance of E. coli O157:H7 strain UT 10 and E. coli ATCC 25922 was determined in brain heart infusion broth at …
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Performance assessment of stabilised/solidified waste-forms
… pH of these soils did not exceed 1 mg/1. The acid resistance of the aged SIS soil was low to moderate and was mainly assured by the carbonates present. This fact will impact on the durability of SIS soils; however, estimates from the literature indicate that the acid resistance of carbonated …
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Transcriptomic and proteomic analysis of lycopene-overproducing Escherichia coli strains
… biosynthesis (hisH); the quinone pool (wrbA); acid resistance (ydeO and gadE); the glyoxylate pathway (iclR); NADPH redox balance (pntB); growth rate reduction; and membrane composition. In the pre-engineered background strain, deleting pntB (~20-25%) and ydeO (~30%) each led to moderately …
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ΚΑΘΑΡΙΣΜΟΣ ΚΑΙ ΙΔΙΟΤΗΤΕΣ ΤΡΙΩΝ ΚΥΤΤΑΡΟΠΛΑΣΜΑΤΙΚΩΝ ΡΙΒΟΝΟΥΚΛΕΑΣΩΝ ΑΠΟ ΣΥΚΩΤΙ ΠΟΝΤΙΚΟΥ
AN ACIDIC, A NEUTRAL AND AN ALKALINE RIBONUCLEASE WERE ISOLATED FROM MOUSE LIVER CYTOPLASM, BY GEL FILTRATION, ION EXCHANGE AND AFFINITY CHROMATOGRAPHY. THE ACIDIC RIBONUCLEASE HYDROLYSES RNA OPTIMALLY AT PH 6.2, IN THE ABSENCE OF SALTS AND AT PH 5.5 IN SOLUTIONS WITH 150 MM OF MONOVALENT SALTS. IT …
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Elucidating mechanisms of toxicity and engineering Escherichia coli for tolerance of short chain fatty acids
… in the production of short chain carboxylic acids during bacterial fermentation is described. This work offers new insights into carboxylic acid toxicity and methods for improvement of microbial tolerance that is important for improving productivity, titer, and yields for economical …
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Autoinducer-2-based quorum sensing of foodborne pathogenic bacteria under food related conditions
… under aerobic conditions. Under heat (55°C) and acid stress (pH 3.0 or 3.5), surviving cell counts of Salmonella were not different (P≥0.05) in the presence and absence of AI-2 activity, indicating that AI-2-based quorum sensing of Salmonella may not be involved in heat and acid stress response. …
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Microstructure, Quasi-Static, And High-Strain Rate Dynamic Characterization Of Metakaolin And Fly Ash Based Geopolymers For Structural Applications
… system, including durability, freeze/thaw, acid resistance, and high temperature resistance [3]. Class F fly ash-based mortar geopolymers provide added fire retardation, reduces crack formation, etc., when added to a concrete mix or used as a mortar system. This thesis compares the …
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The Role of Urease in the Pathogenesis of Edwardsiella ictaluri
… requires the ability to tolerate or alter the acidic environment of the phagolysosome. Growth curves performed at acidic pH and survival assays following extreme acid shock indicate that E. ictaluri is naturally acid resistant and is able to utilize urea to enhance growth and replication at …
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High level indole signalling in Escherichia coli
… coli, including regulation of biofilm formation, acid resistance and pathogenicity. In these cases, E. coli responds to a low, persistent level of indole (0.5-1 mM), similar to the concentration found in an E. coli culture supernatant in stationary phase (typically 0.3-0.8 mM). Recently, it has …
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Physiological characterisation of the neonatal meningitic bacterium Cronobacter sakazakii
… included desiccation stress, heat tolerance, acid resistance and serum resistance assays. The desiccation and serum resistance assays indicated that all of the tested C. sakazakii CC4 and non-CC4 strains showed equal resistance against desiccation and serum. The experiments also indicated that …
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