Hiroshi Yokota

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Bisphenol A, an environmental oestrogenic chemical, was found to conjugate highly with glucuronic acid in male rat liver microsomes studied in vitro. In the various isoforms tested (1A1, 1A3, 1A5, 1A6, 1A7 and 2B1), glucuronidation of bisphenol A and of diethylstilboestrol, a synthetic crystalline compound possessing oestrogenic activity and known to be(More)
The bacterial chemotaxis receptors are transmembrane receptors with a simple signalling pathway which has elements relevant to the general understanding of signal recognition and transduction across membranes, how signals are relayed between molecules in a pathway, and how adaptation to a persistent signal is achieved. In contrast to many mammalian(More)
Small heat shock proteins (sHSPs) belong to a family of 12- to 43-kDa proteins that are ubiquitous and are conserved in amino acid sequence among all organisms. A sHSP homologue of Methanococcus jannaschii, a hyperthermophilic Archaeon, forms a homogeneous multimer comprised of 24 monomers with a molecular mass of 400 kDa in contrast to other sHSPs that(More)
Xenoestrogens, such as bisphenol A and diethylstilbestrol, are glucuronidated by an isoform of UDP-glucuronosyltransferase named UGT2B1 in the livers of adult male rats. In this study, we found that nonylphenol and octylphenol are also conjugated with glucuronic acid by adult rat liver microsomes. Although UDP-glucuronosyltransferase activities toward these(More)
  • H Cho, W Wang, +6 authors D Yan
  • Proceedings of the National Academy of Sciences…
  • 2001
Protein phosphoaspartate bonds play a variety of roles. In response regulator proteins of two-component signal transduction systems, phosphorylation of an aspartate residue is coupled to a change from an inactive to an active conformation. In phosphatases and mutases of the haloacid dehalogenase (HAD) superfamily, phosphoaspartate serves as an intermediate(More)
The pig and human dihydropyrimidine dehydrogenase (DPD) cDNAs were cloned and sequenced. The pig enzyme, expressed in Escherichia coli, catalyzed the reduction of uracil, thymine, and 5-fluorouracil with kinetics approximating those published for the enzyme purified from mammalian liver. DPD could be expressed in significant quantities only when uracil was(More)
The purpose of the present study was to investigate 1) whether activin A can cause primary follicles to become dormant at the resting stage, and 2) the role of the secondary follicle on follicular growth of primary follicles. Preantral follicles (100-120 microm in diameter) harvested from adult mice and cultured in in vitro follicle culture system showed a(More)
Despite the importance of short-chain fatty acids (SCFA) in maintaining the ruminant physiology, the mechanism of SCFA absorption is still not fully studied. The goal of this study was to elucidate the possible involvement of monocarboxylate transporter 1 (MCT1) in the mechanism of SCFA transport in the caprine rumen, and to delineate the precise cellular(More)
BACKGROUND D-Serine is a co-agonist of the N-methyl-D-aspartate subtype of glutamate receptors, a major neurotransmitter receptor family in mammalian nervous systems. D-Serine is converted from L-serine, 90% of which is the product of the enzyme phosphoserine phosphatase (PSP). PSP from M. jannaschii (MJ) shares significant sequence homology with human PSP.(More)
The environmental estrogen bisphenol A, orally introduced into the body, passes through the liver and modulates the endocrine system to elicit irreversible changes in the functioning of reproduction. To elucidate the actual and dynamic metabolism of bisphenol A in the liver before its arrival at target organs, this study evaluated the metabolism and(More)