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Biomedical subjects

R Tao

Publications and source records attributed to R Tao.

At least 91 records · Page 5Linked to original sources
PubMed1987

Primary and secondary structure of bovine retinal S antigen (48-kDa protein).

The complete amino acid sequence of bovine S antigen (48-kDa protein) has been determined by cDNA and partial amino acid sequencing. A 1623-base-pair (bp) cDNA contains an open reading frame coding for a protein of 404 amino acids (45,275 Da). Tryptic peptides and cyanogen bromide peptides of native bovine S antigen were purified and partially sequenced. All of these peptides were accounted for in the long open reading frame. Searching of the National Biomedical Research Foundation data bank revealed no extensive sequence homology between S antigen and other proteins. However, there are local regions of sequence similarity with alpha transducin, including the sites subject to ADP-ribosylation by Bordetella pertussis and cholera toxins and the phosphoryl binding-sites. Secondary structure prediction and circular dichroic spectroscopy show that S antigen is composed predominantly of beta-sheet conformation. Acid-catalyzed methanolysis suggests the presence of low levels of carbohydrate in the molecule.

Amino Acid Sequence↗
PubMed1987

The structure of bovine retinal S-antigen: sequence analysis and identification of monoclonal antibody epitopes and uveitogenic site.

cDNA clones for bovine retinal S-antigen (48K protein) have been isolated and sequenced. Secondary structure prediction for the deduced amino acid sequence suggest that the protein has predominantly beta-conformation with a helical region at the C-terminus. Local regions of sequence similarity with alpha-transducin have been observed, including the sites subject to ADP-ribosylation by pertussis and cholera toxins. Thirty-nine tryptic peptides and ten CNBr peptides of native S-antigen were purified and partially sequenced, showing good agreement with the sequence deduced from the cDNA analysis. The locations of two monoclonal epitopes have been determined by different methods. Furthermore, one synthetic peptide corresponding to the determined amino acid sequence was found to be highly pathogenic for the induction of experimental autoimmune uveitis (EAU). Native S-antigen has further been shown to be glycosylated, which has implications for its antigenicity.

Amino Acid Sequence↗
PubMed1984

High arginine levels in intravenous hyperalimentation abrogate post-traumatic immune suppression.

Trauma victims often suffer immune system failure. Oral arginine has strong immune-enhancing properties. The metabolic, hormonal, and immune effects of increasing concentrations of arginine as part of post-trauma intravenous hyperalimentation (IVH) were studied. Groups of 11-14 rats, 275-350 g, underwent jugular vein catheterization and bilateral closed femoral fractures under anesthesia. IVH was started immediately postinjury at a rate of 0.8-1 ml/100 g body wt/hr and continued for 5 days. Twenty percent dextrose and three different amino acid mixtures were given as follows: (A) FreII (1.55 g ARG/1); (B) FreIII (4.05 g ARG/1); (C) modified FreIII (7.9 g ARG/1). All rats lost weight over the 5-day postinjury period; however, rats in groups B and C lost significantly less weight than rats in group A (-3.4 +/- 0.8% of initial body weight and -3.6 +/- 0.9% vs -6.1 +/- 1.2%, P less than 0.05). Rats in group A had negative cumulative nitrogen balance, while those in groups B and C were in highly positive balance. No significant difference in body weight change or nitrogen balance was noted between groups B and C. Trauma-induced thymic involution as assessed by thymic weight and lymphocyte content was greatest in group A, which received the lowest amount of arginine, and was linearly abrogated by increasing the amount of arginine administered (A less than B less than C). Thymocyte immune responsiveness increased with the amount of arginine given as assessed by mitogenesis in response to Con A (stimulation index: A--151.3 +/- 28.8 vs B--243.6 +/- 29.2, P less than 0.01 vs C--321.8 +/- 22.3, P less than 0.001 vs A and P less than 0.02 vs B) and PHA (A--65.0 +/- 14.3 vs B--67.7 +/- 15.3, NS, vs C--117 +/- 14.0, P less than 0.005 vs A and B).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗