Preferential Induction of Alcohol Dehydrogenase in Coleoptiles of Rice Seedlings Germinated in Submergence Condition

Difference in the growth response to submergence between coleoptiles and roots of rice (Oryza sativa L.) was investigated in 9-d-old rice seedlings. The coleoptile length in the submergence condition was much greater than that in aerobic condition, whereas the root length in the submergence condition was less than that in the aerobic condition. Alcohol dehydrogenase (ADH) activity in the coleoptiles in the submergence condition was much greater than that in the aerobic condition, but ADH activity in the roots in the submergence condition increased slightly. These results suggest that the preferential ADH induction in rice seedlings may contribute to the difference in the growth response between the coleoptiles and roots under low oxygen conditions.     

Effects of ethanol on growth of rice seedlings

Effects of ethanol, the end product of ethanolic fermentation, on the growth of rice (Oryza sativa L.) seedlings were determined as a means of evaluating growth responses under anoxia. The ethanol concentrations in roots and coleoptiles of the seedlings subjected to 48 h-anoxia, and in their culture medium were 23 and 32 µmol g^–1 fresh weight, and 19 µmol ml^–1, respectively. The growth of the roots and coleoptiles of the seedlings was restricted by exogenous ethanol at concentrations above 50 mM and 100 mM, respectively, suggesting that the roots are more sensitive to ethanol than the coleoptiles.     

Novel method using phytase for separating soybean beta-conglycinin and glycinin

A novel method for separating soybean beta-conglycinin and glycinin from defatted soymilk by a phytase treatment was developed. Phytase was added to defatted soymilk (1000FYT/100 g of protein) at pH 6.0, and the mixture incubated for 1 h at 40 degrees C. This procedure separated beta-conglycinin and glycinin without needing a reducing agent or cooling into the soluble and insoluble fractions, respectively. Simultaneously, most of the phytate in both proteins was removed.     

Poly-L-glutamine forms cation channels: relevance to the pathogenesis of the polyglutamine diseases

We report that long-chain poly-L-glutamine forms cation-selective channels when incorporated into artificial planar lipid bilayer membranes. The channel was permeable to alkali cations and H(+) ions and virtually impermeable to anions; the selectivity sequence based on the single-channel conductance was H(+) > Cs(+) > K(+) > Na(+). The cation channel was characterized by long-lived open states (often lasting for several minutes to tens of minutes) interrupted by brief closings. The appearance of the channel depended critically on the length of polyglutamine chains; ion channels were observed with 40-residue stretches, whereas no significant conductance changes were detected with 29-residue tracts. The channel-forming threshold length of poly-L-glutamine was thus between 29 and 40 residues. A molecular mechanics calculation suggests a mu-helix (. Biophys. J. 69:1130-1141) as a candidate molecular structure of the channel. The channel-forming nature of long-chain poly-L-glutamine may provide a clue to the elucidation of the pathogenetic mechanism of the polyglutamine diseases, a group of inherited neurodegenerative disorders including Huntington's disease.     

Relationships between structure and molting hormonal activity of tebufenozide, methoxyfenozide, and their analogs in cultured integument system of Chilo suppressalis Walker

The molting hormonal activity of methoxyfenozide (RH-2485), tebufenozide (RH-5992), five analogs with various alkyl groups, and 18 acyl analogs was measured by using cultured integument of rice stem borers, Chilo suppressalis Walker. The hormonal activity of methoxyfenozide was remarkably high (EC(50) = 1.1 x 10(-9) M), being equivalent to that of tebufenozide (RH-5992). The hormonal activity of several tebufenozide analogs with varying alkyl groups such as CH(3), n-C(3)H(7), i-C(3)H(7), n-C(4)H(9) and n-C(5)H(11) at the para-position of the benzene ring furthest from the tert-butyl group was lower than that of tebufenozide (alkyl group is C(2)H(5)). The activity decreased to varying degrees as a result of replacement of the 3,5-dimethylphenyl moiety of tebufenozide with either a phenyl, naphthyl, or cyclohexyl group. Both 1- and 2-naphthyl derivatives were very active (EC(50) = 4.3 x 10(-8) M and 3.2 x 10(-8) M, respectively) without any significant difference between them. The activity of the 1-cyclohexenyl analog (EC(50) = 1.0 x 10(-7) M) was about 40x that of the corresponding 3-cyclohexenyl analog (EC(50) = 4.4 x 10(-6) M), but 1/100 that of tebufenozide. The activity varied parabolically with respect to the molecular hydrophobicity, and decreased with longer acyl moieties.     

Effect of NADH dehydrogenase-disruption and over-expression on respiration-related metabolism in <Emphasis Type="Italic">Corynebacterium glutamicum</Emphasis> KY9714

The function of type II NADH dehydrogenase (NDH-2) in Gram-positive Corynebacterium glutamicum was investigated by preparing strains with ndh, the NDH-2 gene, disrupted and over-expressed. Although disruption showed no growth defects on glucose minimum medium, the growth rate of the over-expressed strain was lower compared with its parent, C. glutamicum KY9714. Ndh-disruption and over-expression did not lead to a large change in the respiratory chain and energetics, including the cytochrome components and the H⁺/O ratio. However, in the strain that lacked NDH-2, membrane l-lactate oxidase activity increased, while NDH-2 over-expression led to decreased l-lactate and malate oxidase activities. In addition, relatively high cytoplasmic lactate dehydrogenase (LDH) activity was always present as was malate dehydrogenase, irrespective of NDH-2 level. Furthermore, l-lactate or malate-dependent NADH oxidase activity could be reproduced by reconstitution with the membranes and the cytoplasmic fraction isolated from the disruptant. These results suggest that coupling of LDH and the membrane l-lactate oxidase system, together with the malate-dependent NADH oxidase system, operates to oxidize NADH when the NDH-2 function is defective in C. glutamicum.