Ikumi Nakamura

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Honey bee queens produce a sophisticated array of chemical signals (pheromones) that influence both the behavior and physiology of their nest mates. Most striking are the effects of queen mandibular pheromone (QMP), a chemical blend that induces young workers to feed and groom the queen and primes bees to perform colony-related tasks. But how does this(More)
11beta-Hydroxysteroid dehydrogenases (11beta-HSDs) are important steroidogenic enzymes for catalyzing the interconversion of active glucocorticoid (cortisol and corticosterone) and inert 11-keto forms (cortisone and 11-dehydrocorticosterone) in mammals. In teleosts, 11beta-HSD also plays a role in the production of the predominant androgen,(More)
In salmonid fishes, estradiol-17beta (E2) and 17alpha,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P) are the major steroid hormones controlling oocyte growth (vitellogenesis) and final maturation (resumption of meiosis). The aim of this study was to determine changes in mRNAs encoding ovarian steroidogenic enzymes and steroidogenic acute regulatory protein(More)
The effect of gonadotropins, forskolin and IGF-I on steroidogenic enzyme gene expression and E2 production by the rainbow trout follicle were measured. The results indicate that 3β-HSD gene expression is regulated by gonadotropins partially through the cAMP/PKA mechanism. The effect of IGF-I on P450arom mRNA levels suggests that IGF-I is a major regulator(More)
Numerous recent reports have demonstrated effects of estrogenic chemicals on reproductive physiology of fish. However, there is little information available on the regulation of ovarian steroidogenesis by physiological levels of endogenous steroids in teleosts. Therefore, we analyzed the levels of mRNAs encoding steroidogenic proteins in ovaries of(More)
The white sturgeon, Acipenser transmontanus, is a primitive bony fish that is recognized as an important emerging species for aquaculture. However, many aspects of its stress and reproductive physiology remain unclear. These processes are controlled by various steroid hormones. In order to investigate the regulation of steroidogenesis associated with acute(More)
A 45-year-old man was referred to our hospital with a history of multiple erythematous skin lesions of several months' duration. Blood examination revealed extreme hypoproteinemia and hypoalbuminemia, as well as the presence of antinuclear antibodies. A skin biopsy specimen showed liquefaction degeneration at the dermoepidermal junction and dense lymphocyte(More)
In pepper plants (genus Capsicum), the resistance against Tobamovirus spp. is conferred by L gene alleles. The recently identified L variant L(1a) can recognize coat proteins (CPs) of Tobacco mild green mosaic virus Japanese strain (TMGMV-J) and Paprika mild mottle virus Japanese strain (PaMMV-J), but not of Pepper mild mottle virus (PMMoV), as the elicitor(More)
We cloned a cDNA encoding 11β-hydroxysteroid dehydrogenase (11β-HSD) from rainbow trout testis and head kidney. Homology search suggested that the rainbow trout 11β-HSD (rt11β-HSD) homologue was more like mammalian 11β-HSD type 2 than type 1. In order to investigate the enzymatic activity of rt11β-HSD, we conducted transient transfection assays using HEK293(More)
Numerous recent reports have demonstrated effects of estrogenic chemicals on reproductive physiology of fish. However, there is little information available on the regulation of ovarian steroidogenesis by physiological levels of endogenous steroids in teleosts. Therefore, we analyzed the levels of mRNAs encoding steroidogenic proteins in ovaries of(More)