Oxidative burst is one of the earliest responses in plant resistance to pathogen attack. Studies indicate that the oxidative burst is composed of two phases. The first burst is weak and biologically nonspecific, where...Oxidative burst is one of the earliest responses in plant resistance to pathogen attack. Studies indicate that the oxidative burst is composed of two phases. The first burst is weak and biologically nonspecific, whereas the phase Ⅱ burst is massive and produced only as an incompatible interaction. The rapid transient production of active oxygen species plays an important role in plant defense strategy against diseases. It involves: 1) antimicrobial activity, 2) substrate for oxidative cross_linking of cell wall, 3) triggering factor of hypersensitive response, 4) mobile signal inducing local and systemic acquired resistance by itself or its derivatives, 5) induction of phytoalexin accumulation, and 6) regulation of gene transcription. Emerging data indicate that the oxidative burst initiates from the activation of NADPH oxidase system resembling that of animal phagocytes. The generation of active oxygen species by a pH_dependent peroxidase is also present in some plants. Further, there is a complete system in plants to regulate the accumulation and scavenging of active oxygen species to protect plants from secondary infection, and at the same time to avoid the oxidative stress.展开更多
Phytochrome has fascinated plant scientists since its discovery in 1959-1960 by the Beltsville research group of the United States Department of Agriculture. Studies in the first 20 years had evidenced that phytochrom...Phytochrome has fascinated plant scientists since its discovery in 1959-1960 by the Beltsville research group of the United States Department of Agriculture. Studies in the first 20 years had evidenced that phytochrome acts as an universal regulator in plant life adapting its behavior to the environmental light, and developed widely the physiological understanding of phytochrome action. In the following 20 years, some thirty world_wide major laboratories have published over two hundred papers a year on various aspects of the subject, and they are making steady progress. The authors’ work has also contributed to the following aspects: coaction of phytochrome and phytohormone in photomorphogenesis, phytochrome purification, phytochrome regulation of male fertility, as well as phytochrome A gene analysis and expression in photoperiod sensitive genic male sterile rice. In the recent decade significant advances have been made in studies on phytochrome molecules, genes and signal transduction in phytochrome response. This is largely due to the advances in molecular genetics, where experiments using mutants and transgenic plants, particularly in Arabidopsis, that have led to the significant insights at the molecular level. The topics in this review include:(1) Discovery of phytochrome; (2) Functions of phytochrome; (3) Phytochrome molecules; (4) Phytochrome regulation in gene expression.展开更多
AIM To study the effect of phosphorylation ofMAPK and Stat3 and the expression of c-fos andc-jun proteins on hepatocellular carcinogenesisand their clinical significance.METHODS SP immunohistochemistry was usedto dete...AIM To study the effect of phosphorylation ofMAPK and Stat3 and the expression of c-fos andc-jun proteins on hepatocellular carcinogenesisand their clinical significance.METHODS SP immunohistochemistry was usedto detect the expression of p42/44MAPK, p-Stat3,c-fos and c-jun proteins in 55 hepatocellularcarcinomas (HCC) and their surrounding livertissues.RESULTS The positive rates and expressionlevels of p42/44MAPK, p-Stat3, c-fos and c-junproteins in HCCs were significantly higher thanthose in pericarcinomatous liver tissues (PCLT).A positive correlation was observed between theexpression of p42/44MAPK and c-fos proteins, andbetween p-Stat3 and c-jun, but there was nosignificant correlation between p42/44MAPK and p-Stat3 in HCCs and their surrounding livertissues.CONCLUSION The abnormalities of Ras/Rat/MAPK and JAKs/ Stat3 cascade reaction maycontribute to malignant transformation ofhepatocytes. Hepatocytes which are positive forp42/ 44MAPK, c-fos or c-jun proteins may bepotential malignant pre-cancerous cells.Activation of MAPK and Stat3 proteins may be anearly event in hepatocellular carcinogenesis.展开更多
文摘Oxidative burst is one of the earliest responses in plant resistance to pathogen attack. Studies indicate that the oxidative burst is composed of two phases. The first burst is weak and biologically nonspecific, whereas the phase Ⅱ burst is massive and produced only as an incompatible interaction. The rapid transient production of active oxygen species plays an important role in plant defense strategy against diseases. It involves: 1) antimicrobial activity, 2) substrate for oxidative cross_linking of cell wall, 3) triggering factor of hypersensitive response, 4) mobile signal inducing local and systemic acquired resistance by itself or its derivatives, 5) induction of phytoalexin accumulation, and 6) regulation of gene transcription. Emerging data indicate that the oxidative burst initiates from the activation of NADPH oxidase system resembling that of animal phagocytes. The generation of active oxygen species by a pH_dependent peroxidase is also present in some plants. Further, there is a complete system in plants to regulate the accumulation and scavenging of active oxygen species to protect plants from secondary infection, and at the same time to avoid the oxidative stress.
文摘Phytochrome has fascinated plant scientists since its discovery in 1959-1960 by the Beltsville research group of the United States Department of Agriculture. Studies in the first 20 years had evidenced that phytochrome acts as an universal regulator in plant life adapting its behavior to the environmental light, and developed widely the physiological understanding of phytochrome action. In the following 20 years, some thirty world_wide major laboratories have published over two hundred papers a year on various aspects of the subject, and they are making steady progress. The authors’ work has also contributed to the following aspects: coaction of phytochrome and phytohormone in photomorphogenesis, phytochrome purification, phytochrome regulation of male fertility, as well as phytochrome A gene analysis and expression in photoperiod sensitive genic male sterile rice. In the recent decade significant advances have been made in studies on phytochrome molecules, genes and signal transduction in phytochrome response. This is largely due to the advances in molecular genetics, where experiments using mutants and transgenic plants, particularly in Arabidopsis, that have led to the significant insights at the molecular level. The topics in this review include:(1) Discovery of phytochrome; (2) Functions of phytochrome; (3) Phytochrome molecules; (4) Phytochrome regulation in gene expression.
文摘AIM To study the effect of phosphorylation ofMAPK and Stat3 and the expression of c-fos andc-jun proteins on hepatocellular carcinogenesisand their clinical significance.METHODS SP immunohistochemistry was usedto detect the expression of p42/44MAPK, p-Stat3,c-fos and c-jun proteins in 55 hepatocellularcarcinomas (HCC) and their surrounding livertissues.RESULTS The positive rates and expressionlevels of p42/44MAPK, p-Stat3, c-fos and c-junproteins in HCCs were significantly higher thanthose in pericarcinomatous liver tissues (PCLT).A positive correlation was observed between theexpression of p42/44MAPK and c-fos proteins, andbetween p-Stat3 and c-jun, but there was nosignificant correlation between p42/44MAPK and p-Stat3 in HCCs and their surrounding livertissues.CONCLUSION The abnormalities of Ras/Rat/MAPK and JAKs/ Stat3 cascade reaction maycontribute to malignant transformation ofhepatocytes. Hepatocytes which are positive forp42/ 44MAPK, c-fos or c-jun proteins may bepotential malignant pre-cancerous cells.Activation of MAPK and Stat3 proteins may be anearly event in hepatocellular carcinogenesis.
