7-fold. The molecular mass of the enzyme
was estimated to be 35 kDa, determined by SDS-PAGE and by gel filtration. The alpha-L-arabinofuranosidase exhibited maximal activity selleck compound at pH 6.0-7.0 and an optimal temperature at 55 degrees C. The half-life of the a-L-arabinofuranosidase at 60 degrees C was approximately 2 h and it was very stable over a wide pH range for 24h at 4 degrees C. The apparent Michaelis constant K-m value of the a-L-arabinofuranosidase was 0.77 mM for p-nitropenyL-alpha-L-arabinofuranoside. The turnover number (K-cat) and catalytic efficiency (K-cat/K-m) were found to be 14.3 s(-1) and 1.8 104 M-1 s(-1), respectively. Metal ions such as Hg2+ and Cu2+ inhibited enzyme activity, whereas it was strongly activated by Mn2+. The alpha-L-arabinofuranosidase was specific for the alpha-linked arabinoside in the furanoside configuration and can also retain 52% of its activity in the presence of p-nitropheny1-beta-D-xylopyranoside as substrate. alpha-L-arabinofuranosidase acted synergistically with the immobilized endo-beta-1,4-xylanase for the breakdown of alkali-extracted arabinoxylan and in the improvement of xylobiose and monosaccharide production. (c) 2010 Elsevier B.V. All rights reserved.”
“A
high-efficiency plant regeneration check details protocol based on somatic embryo formation for Huining Roquette, an interesting ecotype of Eruca sativa Mill, was established for future transgenic applications. On Murashige and Skoog (MS) medium containing 2,4-dichlorophenoxyacetic acid (2,4-D), SB273005 mouse alone or in combination with 6-benzylaminopurine (BA) or kinetin (KT), the cotyledon explants, cotyledon petioles, and hypocotyls all produced embryogenic callus
(ECs) or somatic embryos (SEs) to different extents. After transferring onto hormone-free MS medium, the ECs or SEs from the different explants and media, all of them developed shoots with a frequency of 6-48%, and then produced roots with a frequency of 2-29%. As regards the probability of shoot differentiation, cotyledon explants appeared similar to hypocotyls, but superior to cotyledon petioles; 2,4-D+KT worked more effectively than 2,4-D alone and 2,4-D+BA for callus induction and shoot differentiation. The optimal hormone combinations for plant regeneration of cotyledon, cotyledon petiole, and hypocotyl explants were 1.0mg/l 2,4-D+0.1mg/l KT, 0.8mg/l 2,4-D+0.3mg/l BA, and 1.0mg/l 2,4-D+0.3mg/l KT, respectively. MS medium with 60-80 g/l sucrose was the most effective for improving SE maturation and germination.”
“A new homologous series of intermetallic compounds containing three-dimensional (3-d) tetrahedral frameworks of gold atoms, akin to hexagonal diamond, have been discovered in four related Sr-Au-Al systems: (I) hexagonal SrAl3-x,Au4+x (0.06(1) smaller than = x smaller than = 0.46(1), P (6) over bar 2m, Z = 3, a = 8.633(1)-8.664(1) angstrom, c = 7.083(2)-7.107(1) angstrom); (II) orthorhombic SrAl2-yAu5+y (y smaller than = 0.05(1); Pnma, Z = 4, a = 8.