By using acetonitrile as the sole nitrogen source, a microbial strain with high nitrilase activity, named as Alcaligenes sp. ECU0401, was newly isolated from soil, which could enantioselectively transform racemic mand...By using acetonitrile as the sole nitrogen source, a microbial strain with high nitrilase activity, named as Alcaligenes sp. ECU0401, was newly isolated from soil, which could enantioselectively transform racemic mandelonitrile into (R)-(?)-mandelic acid, with an enantiomeric excess of >99.9%.展开更多
Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis tha...Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis thaliana (L.) Heynh. by using cDNA an-ay and found that stress responsive genes, such as,Arabidopsis homolog of MEK kinase 1 (ATMEKK1), ReL/SpoT homolog 3 ( At-RSH3), Catalase 1 ( Cat1) and Ferritin 1 (Fer1), were down-regulated by auxin, indicating that auxin regulates ale expression of stress responsive genes. We also demonstrated that nitrilase genes, nitrilase I ( NIT]) and nitrilase 2 (NIT2) involving in indole-3-acetic acid (IAA) biosynthesis, were induced by salinity stress, suggesting that the level of IAA might increase in response to salinity stress. To dissect the signal pathway involved in the interaction, two auxin insensitive mutants, auxin resistant 2 (axr2) and auxin resistant 1-3 (axrl-3) were used. Stress responsive genes were induced by salt stress in wild type and axr2, but not in axr1-3. The result suggests that die interaction between auxin and stress responses may be linked in the ubiquitin pathway.展开更多
以抗稻瘟病品系 G2 0 5为材料 ,应用 c DNA微阵列分别获得了一个受稻瘟病菌诱导的含 NBS- L RR的 c DNA克隆 (暂命名为 RIM1,rice induced by Magnaporthe grisea)和一个受稻瘟病菌抑制的编码腈水解酶 (Nitrilase)的 c DNA克隆(暂命名为...以抗稻瘟病品系 G2 0 5为材料 ,应用 c DNA微阵列分别获得了一个受稻瘟病菌诱导的含 NBS- L RR的 c DNA克隆 (暂命名为 RIM1,rice induced by Magnaporthe grisea)和一个受稻瘟病菌抑制的编码腈水解酶 (Nitrilase)的 c DNA克隆(暂命名为 N IT) ,并通过 Northern得到证实。RFLP分析将 RIM1和 N IT分别定位于水稻第 2和第 3染色体上 ,它们均位于控制水稻稻瘟病部分抗性展开更多
Plants naturally produce cyanide （CN） which is maintained at low levels in their cells by a process of rapid assimilation. However, high concentrations of environmental CN associated with activities such as industri...Plants naturally produce cyanide （CN） which is maintained at low levels in their cells by a process of rapid assimilation. However, high concentrations of environmental CN associated with activities such as industrial pollution are toxic to plants. There is thus an interest in increasing the CN detoxification capacity of plants as a potential route to phytoremediation. Here, Arabidopsis seedlings overexpressing the Pseudomonas fluorescens β-cyanoalanine nitrilase pinA were compared with wild-type and a β-cyanoalanine nitrilase knockout line （△Atnit4） for growth in the presence of exogenous CN. After incubation with CN, ＋PfpinA seedlings had increased root length, increased fresh weight, and decreased leaf bleaching compared with wild-type, indicating increased CN tolerance. The increased tolerance was achieved without an increase in β-cyanoalanine synthase activity, the other enzyme in the cyanide assimilation pathway, suggesting that nitrilase activity is the limiting factor for cyanide detoxification. Labeling experiments with [^13C] KCN demonstrated that the altered CN tolerance could be explained by differences in flux from CN to Asn caused by altered β-cyanoalanine nitrilase activity. Metabolite profiling after CN treatment provided new insight into downstream metabolism, revealing onward metabolism of Asn by the photorespiratory nitrogen cycle and accumulation of aromatic amino acids.展开更多
文摘By using acetonitrile as the sole nitrogen source, a microbial strain with high nitrilase activity, named as Alcaligenes sp. ECU0401, was newly isolated from soil, which could enantioselectively transform racemic mandelonitrile into (R)-(?)-mandelic acid, with an enantiomeric excess of >99.9%.
文摘Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis thaliana (L.) Heynh. by using cDNA an-ay and found that stress responsive genes, such as,Arabidopsis homolog of MEK kinase 1 (ATMEKK1), ReL/SpoT homolog 3 ( At-RSH3), Catalase 1 ( Cat1) and Ferritin 1 (Fer1), were down-regulated by auxin, indicating that auxin regulates ale expression of stress responsive genes. We also demonstrated that nitrilase genes, nitrilase I ( NIT]) and nitrilase 2 (NIT2) involving in indole-3-acetic acid (IAA) biosynthesis, were induced by salinity stress, suggesting that the level of IAA might increase in response to salinity stress. To dissect the signal pathway involved in the interaction, two auxin insensitive mutants, auxin resistant 2 (axr2) and auxin resistant 1-3 (axrl-3) were used. Stress responsive genes were induced by salt stress in wild type and axr2, but not in axr1-3. The result suggests that die interaction between auxin and stress responses may be linked in the ubiquitin pathway.
文摘以抗稻瘟病品系 G2 0 5为材料 ,应用 c DNA微阵列分别获得了一个受稻瘟病菌诱导的含 NBS- L RR的 c DNA克隆 (暂命名为 RIM1,rice induced by Magnaporthe grisea)和一个受稻瘟病菌抑制的编码腈水解酶 (Nitrilase)的 c DNA克隆(暂命名为 N IT) ,并通过 Northern得到证实。RFLP分析将 RIM1和 N IT分别定位于水稻第 2和第 3染色体上 ,它们均位于控制水稻稻瘟病部分抗性
文摘Plants naturally produce cyanide （CN） which is maintained at low levels in their cells by a process of rapid assimilation. However, high concentrations of environmental CN associated with activities such as industrial pollution are toxic to plants. There is thus an interest in increasing the CN detoxification capacity of plants as a potential route to phytoremediation. Here, Arabidopsis seedlings overexpressing the Pseudomonas fluorescens β-cyanoalanine nitrilase pinA were compared with wild-type and a β-cyanoalanine nitrilase knockout line （△Atnit4） for growth in the presence of exogenous CN. After incubation with CN, ＋PfpinA seedlings had increased root length, increased fresh weight, and decreased leaf bleaching compared with wild-type, indicating increased CN tolerance. The increased tolerance was achieved without an increase in β-cyanoalanine synthase activity, the other enzyme in the cyanide assimilation pathway, suggesting that nitrilase activity is the limiting factor for cyanide detoxification. Labeling experiments with [^13C] KCN demonstrated that the altered CN tolerance could be explained by differences in flux from CN to Asn caused by altered β-cyanoalanine nitrilase activity. Metabolite profiling after CN treatment provided new insight into downstream metabolism, revealing onward metabolism of Asn by the photorespiratory nitrogen cycle and accumulation of aromatic amino acids.
