Polyphenol-induced inhibition of the response of na(+)/glucose cotransporter expressed in Xenopus oocytes

To study the effects of polyphenols on the Na(+)/glucose cotransporter (SGLT1) response, SGLT1 was expressed in Xenopus oocytes by injecting cRNA synthesized from the cloned cDNA of the small intestine cotransporter of rats, and the electrical response elicited by glucose or galactose was measured by a voltage clamping method. Most phenol derivatives had no effect on the response. However, the polyphenols (+)-catechin, (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gallate (EGCg), which are components of green tea, caused an inhibition of the response, which was almost independent of glucose concentration. The inhibition constants were estimated to be 2.3 mM for (+)-catechin and 0.45 mM for both ECg and EGCg, assuming the noncompetitive inhibition mechanism. Saponin prepared from tea seeds also inhibited the response significantly. Tannic acid and aqueous extracts of teas induced nonspecific electrical responses in both cRNA-injected and noninjected oocytes at lower concentrations than those that caused an inhibition of the SGLT1 response when their dose-dependent effects were examined. These results are possibly helpful in the development of a dietary supplement for diabetic patients.     

Phylogenetic differentiation of cultivated rice,XXIII. Potentiality of wild progenitors to evolve the Indica and Japonica types of rice cultivars

Summary Studies of intermediate wild-cultivated plants suggested that the Indica-Japonica differentiation of cultivars of Oryza sativa L. has taken place with the domestication of wild plants. The wild progenitor, which is considered to be the Asian form of O. perennis Moench, shows no trace of differentiation into two such types as the Indica and Japonica. To elucidate the potentiality of the wild progenitor to evolve the two types when domesticated, the selfed progenies from an Indica × wild and a japonica × wild cross were examined with regard to three characters known to be useful for distinguishing between the two types. The data showed that Japonica-like plants were derived from the Indica × wild cross and Indica-like plants from the Japonica × wild cross. The Indica-Japonica differentiation was considered to have resulted from selection of incipient domesticates having such potentiality under different climatic conditions; the dynamics was discussed.     

Cold pre-treatment is effective for 1-MCP efficacy in ‘Tsugaru’ apple fruit

1-Methylcyclopropene (1-MCP) treatment maintains apple fruit quality during storage, but its efficacy is dependent on a number of conditions. ‘Tsugaru’ apples are a major early season cultivar in Japan, but because ‘Tsugaru’ fruit produce abundant ethylene, they have a short shelf-life, and efficacy of 1-MCP is not as high with ‘Tsugaru’ as with other cultivars. To improve 1-MCP efficacy, ‘Tsugaru’ fruit were pre-cooled at −1 °C or −3 °C for 24 h before 1-MCP treatment. Ethylene production decreased with the cold treatment, resulting in better storage after 1-MCP treatment. Although ethylene production was low at the end of 24 h of the cold pre-treatment, expression of ACS1, the ethylene receptor genes ERS1, ETR1(a), ETR1b, ETR2 and ETR5, and the cell wall degradation-related gene PG1 all increased with a 24 h cold treatment. It is assumed that these elevated gene expression levels were not caused by ethylene, but more directly by cold stimulus. Thus, a short period of cold stimulus suppresses ethylene production, but induces expression of some genes. 1-MCP treatment was more effective with some initial fruit chilling.     

Trehalose may prevent postsurgical adhesions in a rabbit model of hysterotomy

The adhesion-preventing effect of trehalose in visceral organs was evaluated in a rabbit model. All rabbits underwent a hysterotomy, during which mild abrasion and desiccation was induced on the surfaces of visceral organs. In the control group, the intestines were kept dry during hysterotomy. In the saline and trehalose groups, saline solution and 7% trehalose solution, respectively, were sprayed on the organ surfaces. Adhesion formation on organ surfaces on which abrasion and desiccation were induced declined significantly in the trehalose group compared with the other groups. In contrast, at the hysterotomy site, there was no significant difference in adhesions between groups, suggesting that trehalose prevents adhesions in organs that have developed minor inflammation by abrasion and desiccation.     

Mycobacterium ulcerans infection in an Indian flap-shelled turtle (Lissemys punctata punctata)

We report an atypical mycobacterial infection in an Indian flap-shelled turtle, Lissemys punctata punctata, that died in an aquarium in Japan. At necropsy, the turtle showed multiple white nodules on the capsular surface and parenchyma of various organs such as the liver, spleen, intestine, and lung. Histologically, granulomatous inflammation surrounding a central zone of necrosis was observed. Sections stained by the Ziehl-Neelsen method revealed numerous acid-fast bacilli in the cytoplasm of macrophages and in the central area of necrosis. The organisms were identified as a mycobacterial species by PCR and nucleotide sequence analysis and revealed 98-100% homology to M. ulcerans. This is, to our knowledge, the first report of mycobacteriosis due to M. ulcerans in a turtle.     

Selecting the desirable method for predicting 305‐day lactation yields in Mongolia

In Mongolia, milk production must be improved both quantitatively and qualitatively, and we must find the most desirable method for predicting 305‐day milk yields for cows in Mongolia. Therefore, the predicted 305‐day milk yield from the test interval method (TIM), multiple‐trait prediction (MTP) and the random regression model (RRM) were compared. The daily milk production records during 305 days for cows calving from 1986 to 2007 from the National Livestock Breeding Center in Japan, and the test day records every month for cows calving from 1985 to 2005 from the Hokkaido Dairy Milk Recording and Testing Association were used. Wilmink's model for the average of lactation curve in MTP was adopted. A cubic Legendre polynomials and the parameters of Wilmink's function were used for RRM. The results suggested that RRM was the most desirable method for predicting 305‐day milk yields in Mongolia because estimates by RRM were the most accurate when using over four records. Further analyses will be required to examine the properties of RRM when predicting 305‐day milk yields using test day records in Mongolia.     

Characterization of gelatinolytic enzymes in the skeletal muscle of red sea bream Pagrus major

Gelatinolytic enzymes were partially purified from the skeletal muscle of red sea bream Pagrus major and characterized to obtain information on post mortem tenderization of fish muscle. Four gelatinolytic activities, G1 (90 kDa), G2 (65 kDa), G3 (60 kDa), and G4 (100 kDa), were detected in the Q Sepharose column. G1, the major gelatinolytic enzyme, and G4 were identified as serine proteinases from results of inhibitor spectrum and substrate specificity. By contrast, G2 and G3 were found to be metalloproteinases since these were inhibited by ethylenediamine tetraacetic acid and o-phenanthroline, and activated by 4-aminophenylmercuric acetate. The optimum pH and temperature of these enzymes were in the ranges of 7–9 and 20–40°C, respectively.