Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The measurement of pH of a physiological buffer is an integral part of clinical diagnosis. For the standardization of pH and control of acidity in the physiological region of pH 7 to 9, as found in blood and plasma. Good et al., Ferguson et al., and Bellini et al. have listed hydrogen buffers which are N-substituted amino acids compatible with common biological media. Recently, the acid base behavior of BICINE, in aqueous solution and in different solvent mixtures has been studied by us. Other investigators reported similar results for (CAPS and CAPSO), (BES), (ACES and CHES), TRICINE, TES, ADA, (HEPPS and MOPSO), (MOPS), and (MOBS and HEPBS). These studies have provided precise knowledge about the suitability of a biological buffer. No work seems to have been done on the determination of second stage dissociation constants of 2-(4-Morphlinomethyl)propenoic acid, 2-[bis(2-hydroxyethyl)amino methyl]propenoic acid, 2-[bis(2-hydroxypropyl)aminomethyl]propenoic acid, and 2-[N-ethyl-N-(2-hydroxyethyl)aminomethyl]propenoic acid in aquo-organic solvent mixtures.
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PMID:Buffers for the physiological pH range: acidic dissociation constants of zwitterionic compounds in various hydroorganic media. 1580 Nov 82

Acidity levels greatly affect the taste and flavor of fruit, and consequently its market value. In mature apple fruit, malic acid is the predominant organic acid. Several studies have confirmed that the major quantitative trait locus Ma largely controls the variation of fruit acidity levels. The Ma locus has recently been defined in a region of 150 kb that contains 44 predicted genes on chromosome 16 in the Golden Delicious genome. In this study, we identified two aluminum-activated malate transporter-like genes, designated Ma1 and Ma2, as strong candidates of Ma by narrowing down the Ma locus to 65-82 kb containing 12-19 predicted genes depending on the haplotypes. The Ma haplotypes were determined by sequencing two bacterial artificial chromosome clones from G.41 (an apple rootstock of genotype Mama) that cover the two distinct haplotypes at the Ma locus. Gene expression profiling in 18 apple germplasm accessions suggested that Ma1 is the major determinant at the Ma locus controlling fruit acidity as Ma1 is expressed at a much higher level than Ma2 and the Ma1 expression is significantly correlated with fruit titratable acidity (R (2) = 0.4543, P = 0.0021). In the coding sequences of low acidity alleles of Ma1 and Ma2, sequence variations at the amino acid level between Golden Delicious and G.41 were not detected. But the alleles for high acidity vary considerably between the two genotypes. The low acidity allele of Ma1, Ma1-1455A, is mainly characterized by a mutation at base 1455 in the open reading frame. The mutation leads to a premature stop codon that truncates the carboxyl terminus of Ma1-1455A by 84 amino acids compared with Ma1-1455G. A survey of 29 apple germplasm accessions using marker CAPS(1455) that targets the SNP(1455) in Ma1 showed that the CAPS(1455A) allele was associated completely with high pH and highly with low titratable acidity, suggesting that the natural mutation-led truncation is most likely responsible for the abolished function of Ma for low pH or high acidity in apple.
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PMID:A natural mutation-led truncation in one of the two aluminum-activated malate transporter-like genes at the Ma locus is associated with low fruit acidity in apple. 2280 45