A new regulator of proanthocyanidin (PA) biosynthesis in grapes was found by screening genes coordinately expressed with PA accumulation under different light conditions using a substantially improved method of serial analysis of gene expression (SuperSAGE). This R2R3-MYB transcription factor, VvMYBPAR, shows high protein sequence similarity with PA biosynthesis-regulating plant MYBs, such as VvMYBPA2 and TRANSPARENT TESTA2. Its transcript levels were relatively high in the skins of young berries, whereas the levels were higher in the seeds and at a maximum around veraison. In addition to its response to modified light conditions, the gene responded to abscisic acid application in the skins of cultured berries. Among the PA-specific branch genes, this transcript profile was not correlated with that of VvANR and VvLAR1 but was closely related to that of VvLAR2, suggesting different regulation of PA-specific branch genes from that of a known PA regulator, VvMYBPA2. The PA-specific regulation of VvMYBPAR was confirmed by VvMYBPAR constitutive expression in Arabidopsis in which the transgene specifically induced PA biosynthetic genes and resulted in PA accumulation in plants grown on sucrose-supplemented media to induce anthocyanin synthesis. A transient reporter assay using grapevine cells showed that VvMYBPAR activated the promoters on PA-specific branch genes and candidate genes associated with modification and transport of monomeric PA precursors, as well as the promoters of VvCHS3 and VvF3'5'Hd in the common flavonoid pathway, but not that of VvUFGT on the anthocyanin-specific branch. This new factor suggests the polygenic regulation of PA biosynthesis in grapes by closely related MYB transcription factors.
Five bitter-tasting peptides were isolated from charcoal-untreated sake, following a Sepabeads resin separation, an initial reverse-phase chromatography (RP-HPLC), a gel permeation-chromatography, and a second RP-HPLC. The isolated peptides consisted of six to thirteen amino acid residues. The N-termini were uniformly pyroglutamate residues. Based on the rice protein database, the peptides were derived from two di#erent N-termini of the rice glutelin acidic subunit. One of them was reported as a prolyl endopeptidase inhibitor. The thirteen amino acid peptides in charcoal-untreated ginjyo-type sakes were lower than that in charcoal-untreated jyunmai-type sakes. The thirteen amino acid peptides were not detected in the commercial ordinary-type sake analyzed. The concentration of analyzed peptides of nine to thirteen amino acid residues in charcoal-untreated sake exceeded their preliminary estimated sensory threshold values, suggesting that they contribute to the sensory quality of charcoal-untreated sake.
Six Oriental cultivars of Vitis vinifera, which are native to Japan or China, as well as 2 cultivars of V. labrusca as references, were characterized by 6 microsatellite markers with coded reference alleles. One allele in Oriental cultivars and 3 in V. labrusca have not been reported for Occidental cultivars. Assignment analysis using these data and reported data with grouping of V. labrusca, Oriental cultivars, and vine-growing regions of Occidental cultivars showed that 4 out of 8 Oriental cultivars, but only 3 out of 162 Occidental cultivars, were assigned to Oriental cultivars. These assignments are in accordance with the genetic distances calculated from microsatellite data. These results show that Oriental cultivars have a certain degree of genetic difference from Occidental cultivars within the species V. vinifera.
Retrogradation of starch in steamed rice grains under sake-making conditions was examined. The enthalpy change derived from retrogradation of amylopectin increased during the koji and sake mash processes. Ethanol in the sake mash accelerated retrogradation of amylopectin. Enzyme digestibility and properties of endosperm starches of 136 Japanese rice samples used for sake production were examined. A digestion test of steamed rice grains was conducted after 24 h storage at 15 C to estimate more accurately digestibility during the sake-making process. The ratio of short-to-long chain amylopectin exhibited a significant correlation with enzyme digestibility, suggesting that the structure of amylopectin may be used as a predictor of digestibility. The gelatinization temperature of brown milled rice and purified starch measured by DSC (differential scanning calorimetry) correlated well with the ratio of short-to-long chain amylopectin and with enzyme digestibility. Furthermore, the pasting temperature of milled rice as measured by RVA (Rapid Visco Analyser) correlated well with the ratio of short-to-long chain amylopectin and with enzyme digestibility. Therefore, DSC and RVA appear to be useful tools for estimating enzyme digestibility of steamed rice grains under sake-processing conditions because the measurements are done rapidly and require only small weights of brown milled rice flour samples.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.