88 research outputs found
Excretion of <scp>l</scp>-malic acid in the chicken
No full text The mechanism of excretion of malic acid has been studied during infusion of sodium salts of l-malic acid, succinic acid and malonic acid in the chicken. Infusion of preformed l-malate results in its filtration and reabsorption in the nephron; no renal tubular secretion is seen under these circumstances. However, when succinate is infused in the renal portal circulation, malate is excreted in larger amounts on the ipsilateral side than on the other. Malonate, a succinoxidase inhibitor, not only fails to abolish this excretion but actually enhances it. Infusion of malonate alone does not produce any excretion of malic acid. It is concluded that the renal tubular secretion of l-malate is limited to that which is synthesized in the tubular cells and does not occur even when large amounts of infused l-malate are present in the peritubular circulation. The enhancement of malate excretion by malonate during succinate infusion may occur from either malonate decarboxylation or malonate suppression of a malate reabsorptive limb in the nephron. </jats:p
Women\u27s goodwill tour to Weatherford on behalf of Fort Worth Frontier Centennial
No full textWomen\u27s goodwill tour to Weatherford on behalf of Fort Worth Frontier Centennial; Mrs. Edwin T. Phillips ties cowboy kerchief on R.G. Boger, president of Weatherford College; l. to r., Mrs. Whitehead, Miss Lotspeich, and Charlotte Max, 05/14/1936https://mavmatrix.uta.edu/specialcollections_startelegram1930s/2923/thumbnail.jp
Ditch Valley Irrigation Project
No full textPhotograph of (L-R): R.A. Lotspeich and Orvin Shuman, (Harper County farmers) and County Commissioner Oden Sheppard shown at the inlet of two large culverts installed under new farm-to-market road in Harper County. Culverts will be utilized to carry overhead water in the Ditch Valley Irrigation project
ASCORBATE-SENSING uORF CONTROLS GDP-L-GALACTOSE PHOSPHORYLASE (GGP) mRNA TRANSLATION
No full textAccording to the scanning model of eukaryotic translation initiation, ribosomes bind near the 5’ cap of an mRNA and then initiate translation at the first start codon they encounter as they progress down the mRNA. Upstream open reading frames (uORFs) can regulate translation initiation at downstream start codons. Recently, a uORF in the GDP-L-galactose phosphorylase (GGP) mRNA was reported to mediate autoregulation of ascorbate, or Vitamin C, production. Ascorbate is an essential enzymatic cofactor and antioxidant in plants and animals. Ascorbate concentrations are tightly regulated in plants through post-transcriptional repression of GGP, the major enzyme controlling ascorbate biosynthesis. Key attributes of the noncanonical GGP uORF include: (1) initiation at either a near-cognate start codon or an AUG codon in poor context; (2) it encodes a 32-65 residue peptide containing conserved motifs; and (3) ribosome profiling indicates the presence of an elongation pause at the uORF C-terminus. These attributes suggest that the GGP uORF is a novel upstream Conserved Coding region (uCC), a new paradigm of translational control involving a uORF whose initiation at a weak start site is triggered by queuing of scanning ribosomes behind an elongating ribosome paused at a conserved amino acid motif within the uCC. We hypothesize that ascorbate promotes pausing of translation elongation in the uORF to enhance uORF translation and to repress translation of GGP. To assess ascorbate mediated GGP repression by the uORF, we examined reporter constructs in mammalian cell lines and in rabbit reticulocyte lysate in vitro translation systems. Alignment of 20 algae species’ GGP uORFs shows absolute conservation of five amino acid motifs. Consistent with the GGP uORF being a uCC, conservation of all five motifs and their spacing is essential for regulation of GGP mRNA translation by ascorbate in vivo and in vitro, and the elongation pause is specific to ascorbate. Ribosome profiling from Chlamydomonas reinhardtii and Solanum lycopersicum showed an elongation pause at the C-terminal glycine repeat. In support of the queuing model, reducing ribosome loading by inserting a cap-proximal stem-loop in the GGP mRNA abolished ascorbate specific regulation of GGP expression. Taken together, these data indicate that the GGP uORF is a uCC. We propose that ascorbate interacts with conserved residues of the uCC nascent peptide within the ribosome exit tunnel, causing an elongation pause that regulates GGP mRNA translation
Effect of Various Amino Acids on the Renal Tubular Reabsorption of Inorganic Sulfate in the Dog
No full text Various amino acids depress the sulfate-Tm in the dog. The effects of l-alanine, glycine, d-alanine and l-arginine are compared. The capacity of any one of these amino acids to depress sulfate-Tm correlates directly with maximal rate of reabsorption of the amino acid. The nature of the amino acid inhibition, its relation to amino acid reabsorption, the amino-acidurias and some general problems of renal tubular reabsorption are discussed. </jats:p
THE EXCRETION OF l-MALIC ACID IN RELATION TO THE TRICARBOXYLIC ACID CYCLE IN THE KIDNEY*
No full text- …
