Biomedical subjects

Masayuki Kita

Publications and source records attributed to Masayuki Kita.

4 recordsLinked to original sources

PubMed2005

Molecular cloning and functional characterization of two apple S-adenosylmethionine decarboxylase genes and their different expression in fruit development, cell growth and stress responses.

Two full-length S-adenosylmethionine decarboxylase (SAMDC) cDNAs, MdSAMDC1 and MdSAMDC2, were isolated from apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.]. Both cDNAs encoded tiny and small ORFs in addition to the SAMDC ORFs, and genomic sequences of MdSAMDC1 and MdSAMDC2 contained two or three introns in the 5' upstream regions, respectively. Yeast complementation experiment indicated that two MdSAMDCs encoded functional proteins, and that the tiny and small ORFs possibly repressed their translation efficiency. RNA gel blot analysis showed that MdSAMDC1 were differentially regulated in fruits depending on the developmental stage and in cell suspension during the culture period, but MdSAMDC2 did not. In contrast, MdSAMDC2 was positively induced by cold and salt stresses, but MdSAMDC1 was not. These results suggest that MdSAMDC1 is mainly involved in fruit development and cell growth while MdSAMDC2 in stress responses, compared with their respective counterpart.

Adenosylmethionine Decarboxylase↗

PubMed2005

Acetate and ethanol production from H2 and CO2 by Moorella sp. using a repeated batch culture.

The growth inhibition of Moorella sp. HUC22-1 by undissociated acetic acid was analyzed using a non-competitive inhibition model coupled with a pH inhibition model. In the cells grown on H2 and CO2, the inhibition constant, K(p) of the undissociated acetic acid was 6.2 mM (164 mM as the total acetate at pH 6.2, pKa = 4.795, 55 degrees C), which was 1.5-fold higher than that obtained in cells grown on fructose. When a pH-controlled batch culture was performed using a fermentor at pH 6.2 with H2 and CO2, a maximum of 0.92 g/l of dry cell weight and 339 mM of acetate were produced after 220 h, which were 4.4- and 6.8-fold higher than those produced in the pH-uncontrolled batch culture, respectively. In order to reduce acetate inhibition in the culture medium, a repeated batch culture with cell recycling was performed at a constant pH with H2 and CO2. At a pH of 6.2, the total acetate production reached 840 mmol/l-reactor with 4.7 mmol/l-reactor of total ethanol production after 420 h. When the culture pH was maintained at 5.8, which was the optimum for ethanol production, the total ethanol production reached 15.4 mmol/l-reactor after 430 h, although the total acetate production was decreased to 675 mmol/l-reactor.

Acetates↗

PubMed2003

Putative PIP1 genes isolated from apple: expression analyses during fruit development and under osmotic stress.

To gain insight into the function of plasma membrane intrinsic protein (PIP) genes in apple, two genes, MdPIP1a and MdPIP1b, were isolated. MdPIP1 expression was in accordance with the volume increase during fruit development, which is a loading process of water and solutes. In addition, the expression of MdPIP1 was up-regulated in the stems by osmotic stress. These results indicate that MdPIP1 may play important roles not only in fruit expansion, but also in maintaining water homeostasis under stress conditions.

Carrier Proteins↗

PubMed2002

Flavonol synthase gene expression during citrus fruit development.

We isolated a cDNA clone (CitFLS) encoding flavonol synthase (FLS) from the satsuma mandarin (Citrus unshiu Marc.) fruit and investigated the steady state of CitFLS RNA expression during the fruit development. The CitFLS was 1274 bp long, encoded 335 amino acid residues, and belonged to a family of 2-oxoglutarate-dependent dioxygenases. The level of CitFLS transcript was higher in the young leaves than in the old leaves, and it was high at the early developmental stage and low at the mature stage in the juice sacs/segment epidermis (edible part). On the other hand, the CitFLS transcript increased in the peel during fruit maturation. These results indicated that the satsuma mandarin CitFLS was differentially regulated in the developmental stage and in a tissue-specific manner. Additionally, satsuma mandarin peel tissues produced rutin (a flavonol glycoside) from an exogenous dihydroquercetin (taxifolin), indicating the ability of these tissues to produce flavonols.

Journal Article↗