Mechanism for deformation of wood as a honeycomb structure II: First buckling mechanism of cell walls under radial compression using the generalized cell model

Coniferous woods were modeled as honeycomb cellular solids consisting of hexagonal-prism tracheids to examine the mechanism for radial compression. Because of the abrupt breaks of radial cell walls, it was assumed that the flrst break followed Euler's equation of buckling. The nominal stress at the buckling of the radial cell wall was theoretically obtained based on this assumption, and the actual nominal stress was obtained experimentally. The theoretical stress was found to correspond almost to the experimental value. This finding suggests that the abrupt first break that occurs in wood under radial compression can be mainly attributed to the buckling of radial cell walls.Part of this work was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, April 1997 and at the 1997 meeting of the Research Society of Rheology in the Japan Wood Research Society, Tsukuba, December 1997     

Purification and characterization of two novel cysteine protease inhibitors, Eel-CPI-2 and Eel-CPI-3, in the skin mucus of the Japanese eel Anguilla japonica

We have discovered multiple acidic cysteine protease inhibitors, in addition to the known Eel-CPI-1, in the skin mucus extract of the Japanese eel Anguilla japonica by using the two-dimensional gel system of gelatin reverse zymography. Two of the acidic inhibitors, which we have named Eel-CPI-2 and Eel-CPI-3, were purified to homogeneity by anion exchange chromatography on a column of DEAE-Sepharose CL-6B, followed by fast protein liquid chromatography on Superdex 75 10/300 GL and HiTrap Q HP columns. The amino acid compositions of Eel-CPI-2 and Eel-CPI-3 were found to be almost identical and closely similar to that of the eel galectin AJL1. The molecular masses of Eel-CPI-2 and Eel-CPI-3 were elucidated to be 16,089.080 and 16,089.137 Da, respectively, by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The apparent dissociation constant of Eel-CPI-2 and Eel-CPI-3 for cysteine protease papain was determined to be 1.79 × 10⁻⁷ and 1.05 × 10⁻⁷ M, respectively, by a quartz crystal microbalance technique.     

Novel 1,3,5-triazine derivatives with herbicidal activity

New fluoroalkyl-substituted 1,3,5-triazine derivatives were synthesized and screened for herbicidal activity using a greenhouse pot test. Surprisingly, a series of 2-alkyl-4-fluoroalkyl-6-aralkylamino-1,3,5-triazines e.g. 6-(4-bromobenzylamino)-2-methyl-4-trifluoromethyl-1,3,5-triazine was found to possess strong pre- and post-emergence herbicidal activities, although the conventional herbicidal 1,3,5-triazines generally should have a 2-substituted-4,6-diamino-1,3,5-triazine structure for herbicidal activity. Our compounds show strong Photosynthetic Electron Transport inhibitory activity (PI₅₀ c 7). Although their herbicidal effect is considered to be caused by a process similar to that for the conventional 1,3,5-triazine herbicide atrazine, they can control atrazine-resistant Chenopodium album effectively, and will thus form promising trial compounds for new triazine herbicide design.     

Role of the rice blast resistance gene Pi-cd in rice (Oryza sativa) breeding programmes

A series of DNA markers for various agronomic traits may accelerate the success of marker-assisted selection in practical plant breeding programmes. Here, we developed DNA markers for the blast resistance gene Pi-cd. In this study, we examined the effects of the Pi-cd locus on not only blast resistance but also agronomic traits in agriculture. We developed three pyramiding lines (PLs) coupling Pi-cd with three blast resistance genes, pi21, Pi35 and Pi39. The effect of Pi-cd on blast resistance was dependent on the coupled resistance genes. Then, we evaluated the effects of Pi-cd on 13 agronomic traits. Amylose content and 1,000-grain weight showed significant differences between the PLs and current commercial varieties, which had no negative effects on agronomic trait values. Furthermore, we investigated the distribution of genotype for the Pi-cd locus among varieties of upland rice. The KT genotype specific to rice blast resistance may be predominant in the varieties. The results suggested that Pi-cd has the potential to be useful for improving blast resistance in rice breeding programmes.