No abstract

Waxy rice is used for staple and processed foods, and for its effective breeding an evaluation selection index has been required. Here, the chain-length distribution of amylopectin from japonica waxy rice varieties with different hardness of rice cake were analyzed by the fluorescent labeling HPSEC method, and the relation of the unit chain-length distribution to the hardness was examined. The difference among varietals was found in the amylopectin structure. Waxy rice producing soft cake, such as Hakuchoumochi, has more short chains (A B 1), and fewer long chains (B 2 B 3), than that producing hard cake, such as Koganemochi. The molar ratio of short chains (A B 1) long chains (B 2 B 3), which is considered to be the number of chains comprising a cluster of amylopectin, was 10.1 11.7, being different among the varieties tested. The molar ratio determined by fluorescent response was much more reliable than the weight ratio determined by IR response because of the stable base line during HPLC. A negative correlation was found between the molar ratio and the hardening of rice cake. Therefore, the molar ratio (A B 1) (B 2 B 3) of amylopectin unitchains seemed to be one of useful evaluation selection indexes for breeding of waxy rice. An index, or molar ratio, lower than 11 appeared to be suitable for processing use, and one higher than 11.5 for principal food use.

No abstract

AM -toxins are host-specific phytotoxins of the Alternaria alternata apple pathotype, which induce necrosis on apple leaves. In this study, we developed a new assay to measure the necrotic activity of AM -toxin analogs using cultured leaves from meristem cells. This method was not only more sensitive to AM -toxin I, but also more reliable than the previous one that used tree leaves due to the homogeneous nature of cultured leaves and to the method of application of toxins. U sing this assay method we investigated a structure-activity relationship of AM -toxin analogs synthesized in this study. Most residues and the macrocyclic ring structure were strictly recognized by AM -toxin putative receptor, whereas the L-Ala binding subsite of the receptor allowed for side chain structures with various stereoelectronic properties. These findings are important for designing ligands for further experimental probing of the nature of the receptor.

JvaAThe cyclic depsipeptides, AM-toxins I and II and AMtoxin I analogs, were eMciently and rapidly prepared by the Fmoc-based solid-phase method for the synthesis of iine2r depsipeptides, with IVL[(dimethylamino)-IHLI,2,3-triazolo[4,5-blpyridin-1-ylmethylene]-IVLmethylmethanaminium hexafiuorophosphate IVLoxide (HATU) being used for their subsequentcyclization. CH211CHs1 R CV3,CH3