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Biomedical subjects

Y Koresawa

Publications and source records attributed to Y Koresawa.

7 recordsLinked to original sources
PubMed2001

A synthetic dDAF (CD55) gene based on optimal codon usage for transgenic animals.

The human DAF (CD55) gene was chosen as a representative molecule in a xenotransplantation study. The gene was synthesized in order to adapt its codons to those which are more frequent in mammals, especially pigs, and the expression levels were then examined in Chinese hamster ovarian (CHO) cells, swine endothelial cell (SEC) and transgenic mice. A significant increase in protein production with no detectable mRNA elevation was observed in the transfectants of synthetic DAF (sDAF), compared with the wild-type DAF (wtDAF) and delta-SCR1 wild-type DAF (Delta1wtDAF). Consistent with the in vitro data, the expression of DAF in mice that carry sDAF was higher than Delta1wtDAF in many organs, especially the pancreas. The sDAF showed a high level of expression in SEC and transgenic mice, suggesting that it will be useful in the development of transgenic pigs with high levels of expression.

Animals↗
PubMed2000

Synthesis of a new Cre recombinase gene based on optimal codon usage for mammalian systems.

The origin of the Cre recombinase gene is bacteriophage P1, and thus the codon usages are different from in mammals. In order to adapt this codon usage for mammals, we synthesized a "mammalian Cre recombinase gene" and examined its expression in Chinese hamster ovarian tumor (CHO) cells. Significant increases in protein production as well as mRNA levels were observed. When the recombination efficiency was compared using CHO cell transfectants having a cDNA containing loxP sites, the "mammalian Cre recombinase gene" recombined the loxP sites much more efficiently than the wild-type Cre recombinase gene.

Amino Acid Sequence↗
PubMed1999

Adverse effects of excess DL-methionine in calves with different body weights.

Adverse effects of excess methionine were examined using 12 Holstein bull calves trained to maintain reflex closure of the reticular groove even after weaning at 5 wk of age. Two nitrogen balance experiments were conducted for 2 wk each from 6 wk (Stage 1; BW = 62 kg) and 12 wk of age (Stage 2; BW = 103 kg) by dividing the calves into three groups at each stage. Calves were fed a corn-soybean meal diet at 62 g/kg of metabolic BW at both stages. At Stage 1, feed efficiency (gain:feed intake) and nitrogen retention did not differ between the group supplemented with .333 g of DL-methionine and .111 g of L-lysine monohydrochloride/kg BW per day and the group supplemented with isonitrogenous diammonium citrate, although the level of DL-methionine was considered to be enough to induce toxicity. Conversely, administration of isonitrogenous casein increased nitrogen retention. At Stage 2, administration of the same levels of methionine and lysine resulted in reduced feed intake, depressed nitrogen retention, and BW loss. Conversely, administration of the isonitrogenous casein did not increase nitrogen retention compared with the supplement of isonitrogenous diammonium citrate. Administration of excess methionine and lysine increased plasma methionine concentrations up to 230 (Stage 1) or 190 micromol/dL (Stage 2). Plasma lysine concentrations were less than 24 micromol/dL at every stage. Administration of the amino acid mixture decreased plasma concentrations of branched-chain amino acids and phenylalanine more obviously at Stage 2 than at Stage 1. These results indicated that abomasal administration of .333 g of DL-methionine/kg BW per day induced methionine toxicity at Stage 2 but methionine imbalance at Stage 1.

Animals↗
PubMed1995

[Study of biochemical gene markers in the Mongolian gerbil (Meriones unguiculatus)].

The present study was conducted to analyze biochemical marker genes and to clarify genetic variation in 4 Mongolian gerbil (Meriones unguiculatus) strains (MGS/Sea, MON/Jms Gbs, Kwl: Mongolian Gerbil and Hos: Mongolian gerbil) maintained in Japan. Cellulose acetate, starch gel or agar gel electrophoresis was used. Of the 23 kinds of proteins detected, variation was found only in liver acid phosphatase (Acp2); no variation in other proteins was found within or among strains. The results suggest that these 4 Mongolian gerbil strains are genetically similar. A strain difference was found in the Acp2 locus of liver acid phosphatase. The Kwl: Mongolian Gerbil strain had a band of Acp2 locus, whereas MGS/Sea, MON/Jms and Hos: Mongolian gerbil strains did not.

Acid Phosphatase↗