China is a great agricultural country with large population, limited soilresources and traditional farming mode, so the central government has been attaching greatimportance to the development of agriculture and put f...China is a great agricultural country with large population, limited soilresources and traditional farming mode, so the central government has been attaching greatimportance to the development of agriculture and put forward a new agricultural technologyrevolution ― the transformation from traditional agriculture to modern agriculture and fromextensive farming to intensive farming. Digital agriculture is the core of agriculturalinformatization. The enforcement of digital agriculture will greatly promote agricultural technologyrevolution, two agricultural transformations and its rapid development, and enhance China'scompetitive power after the entrance of WTO. To carry out digital agriculture, the frame system ofdigital agriculture is required to be studied in the first place. In accordance with the theory andtechnology of digital earth and in combination with the agricultural reality of China, this articleoutlines the frame system of digital agriculture and its main content arid technology support.展开更多
Vitellogenin (Vtg) is the precursor of yolk protein. Its expression and secretion are estrogen-regulated and are crucial for oocyte maturation. An in vitro xenoestro- gen screening model was established by measuring V...Vitellogenin (Vtg) is the precursor of yolk protein. Its expression and secretion are estrogen-regulated and are crucial for oocyte maturation. An in vitro xenoestro- gen screening model was established by measuring Vtg in- duction in cultured primary hepatocytes from crucian carp. Vtg production was detected by biotin-avidin sandwich ELISA method while Vtg and cytochrome P4501A1 (CYP1A1) mRNA induction were measured by semi- quan- titative PCR-primer dropping technique. Vtg and Vtg mRNA were dose-dependently induced by diethylstilbestrol (DES, 0.2—200 ng/mL) in hepatocytes of crucian carp. Co-treatment of the DES-induced hepatocytes with either 2,3,7,8-TCDD (TCDD, 0.1—4 pg/mL) or benzo[a]pyrene (B[a]P, 5—1000 ng/mL) resulted in a reduction of Vtg pro- duction and an increment of CYP1A1 mRNA expression both in a dose dependent manner, indicating the anti-estro- genic effects of the compounds. However, at lower tested concentrations, TCDD (0.1, 0.2 pg/mL), B[a]P (5 ng/mL) seemed to have a potentiating effect on Vtg expression and secretion, although by their own these compounds had no observable estrogenic effect on Vtg induction. Tamoxifen (a selective estrogen receptor modulators, 1 nmol/L—1 μmol/L), and β-naphtho-flavone (β-NF, an aryl hydrocarbon receptor inducing compounds, 2.5—1000 ng/mL) also were employed to study the possible interactions in DES-induced Vtg ex- pression. In co-treatment of the DES-induced hepatocytes with β-NF or tamoxifen, the decrease in Vtg production did parallel induction of CYP1A1 for β-NF, but tamoxifen inhib- ited Vtg induction did not parallel induced CYP1A1 expres- sion in all test concentrations. On the contrary, it was found that in co-treatment of the TCDD-induced hepatocytes with DES, TCDD induced CYP1A1 mRNA production was inhib- ited by DES also. These results implicated a possible cross talk between estrogen receptor- and aryl hydrocarbon re- ceptor-mediated pathways in the hepatocytes.展开更多
A novel method was developed to use glutinous broomcorn millets (Panicum miliaceum L.) as solid substrate to make cultures of the entomophthoralean fungus Pandora delphacis specifically pathogenic to planthoppers, lea...A novel method was developed to use glutinous broomcorn millets (Panicum miliaceum L.) as solid substrate to make cultures of the entomophthoralean fungus Pandora delphacis specifically pathogenic to planthoppers, leafhop-pers and aphids. Steamed millets with water content of 45% were inoculated with a liquid culture of P. delphacis at a ratio of 20% (v/w) and then incubated at 25℃ and L:D 12:12. The millets cultured for 3—17 d exhibited high potential for co-nidial production. The 5-d-old millet culture sporulated most abundantly, discharging up to 17.12 (1.31) 104 conidia/ millet. The cultures incubated for 7—11 d also had a satis-factory sporulation capability, yielding 13.00—13.90 104 conidia/millet. Compared to 2.32 (0.34) 104 conidia dis-charged from each of Myzus persicae adults killed by P. del-phacis and a ≤60-h duration of sporulation, each of the millets cultured for 5—11 d produced 5.6—7.4 times more conidia with an over doubled duration for conidial discharge (144 h). Among 106 M. persicae adults exposed to the shower of conidia discharged from the cultured millets, a total mor-tality of 69.8% caused by P. delphacis infection was observed within 7 d after exposure, but no death was attributed to the fungal infection in the aphids unexposed. The results indi-cate that the millet cultures of P. delphacis are biologically similar to aphid cadavers killed by the same fungus. Due to the superiority of the cultured millets to the cadavers in sporulation potential and duration, the method for making cultures of P. delphacis on the broomcorn millets is highly recommended for use in study of entomophthoralean fungi for microbial control. This is the first report on the success of the solid culture of Pandora species on cereals.展开更多
文摘China is a great agricultural country with large population, limited soilresources and traditional farming mode, so the central government has been attaching greatimportance to the development of agriculture and put forward a new agricultural technologyrevolution ― the transformation from traditional agriculture to modern agriculture and fromextensive farming to intensive farming. Digital agriculture is the core of agriculturalinformatization. The enforcement of digital agriculture will greatly promote agricultural technologyrevolution, two agricultural transformations and its rapid development, and enhance China'scompetitive power after the entrance of WTO. To carry out digital agriculture, the frame system ofdigital agriculture is required to be studied in the first place. In accordance with the theory andtechnology of digital earth and in combination with the agricultural reality of China, this articleoutlines the frame system of digital agriculture and its main content arid technology support.
文摘Vitellogenin (Vtg) is the precursor of yolk protein. Its expression and secretion are estrogen-regulated and are crucial for oocyte maturation. An in vitro xenoestro- gen screening model was established by measuring Vtg in- duction in cultured primary hepatocytes from crucian carp. Vtg production was detected by biotin-avidin sandwich ELISA method while Vtg and cytochrome P4501A1 (CYP1A1) mRNA induction were measured by semi- quan- titative PCR-primer dropping technique. Vtg and Vtg mRNA were dose-dependently induced by diethylstilbestrol (DES, 0.2—200 ng/mL) in hepatocytes of crucian carp. Co-treatment of the DES-induced hepatocytes with either 2,3,7,8-TCDD (TCDD, 0.1—4 pg/mL) or benzo[a]pyrene (B[a]P, 5—1000 ng/mL) resulted in a reduction of Vtg pro- duction and an increment of CYP1A1 mRNA expression both in a dose dependent manner, indicating the anti-estro- genic effects of the compounds. However, at lower tested concentrations, TCDD (0.1, 0.2 pg/mL), B[a]P (5 ng/mL) seemed to have a potentiating effect on Vtg expression and secretion, although by their own these compounds had no observable estrogenic effect on Vtg induction. Tamoxifen (a selective estrogen receptor modulators, 1 nmol/L—1 μmol/L), and β-naphtho-flavone (β-NF, an aryl hydrocarbon receptor inducing compounds, 2.5—1000 ng/mL) also were employed to study the possible interactions in DES-induced Vtg ex- pression. In co-treatment of the DES-induced hepatocytes with β-NF or tamoxifen, the decrease in Vtg production did parallel induction of CYP1A1 for β-NF, but tamoxifen inhib- ited Vtg induction did not parallel induced CYP1A1 expres- sion in all test concentrations. On the contrary, it was found that in co-treatment of the TCDD-induced hepatocytes with DES, TCDD induced CYP1A1 mRNA production was inhib- ited by DES also. These results implicated a possible cross talk between estrogen receptor- and aryl hydrocarbon re- ceptor-mediated pathways in the hepatocytes.
基金supported by the National Natural Science Foundation of China(Grant No.30070514)the Special Fund for Graduate Study Programs in Chinese Universities(Grant No.200203335041)the‘Cheung Kong Scholars Programme’,Ministry of Education,China.
文摘A novel method was developed to use glutinous broomcorn millets (Panicum miliaceum L.) as solid substrate to make cultures of the entomophthoralean fungus Pandora delphacis specifically pathogenic to planthoppers, leafhop-pers and aphids. Steamed millets with water content of 45% were inoculated with a liquid culture of P. delphacis at a ratio of 20% (v/w) and then incubated at 25℃ and L:D 12:12. The millets cultured for 3—17 d exhibited high potential for co-nidial production. The 5-d-old millet culture sporulated most abundantly, discharging up to 17.12 (1.31) 104 conidia/ millet. The cultures incubated for 7—11 d also had a satis-factory sporulation capability, yielding 13.00—13.90 104 conidia/millet. Compared to 2.32 (0.34) 104 conidia dis-charged from each of Myzus persicae adults killed by P. del-phacis and a ≤60-h duration of sporulation, each of the millets cultured for 5—11 d produced 5.6—7.4 times more conidia with an over doubled duration for conidial discharge (144 h). Among 106 M. persicae adults exposed to the shower of conidia discharged from the cultured millets, a total mor-tality of 69.8% caused by P. delphacis infection was observed within 7 d after exposure, but no death was attributed to the fungal infection in the aphids unexposed. The results indi-cate that the millet cultures of P. delphacis are biologically similar to aphid cadavers killed by the same fungus. Due to the superiority of the cultured millets to the cadavers in sporulation potential and duration, the method for making cultures of P. delphacis on the broomcorn millets is highly recommended for use in study of entomophthoralean fungi for microbial control. This is the first report on the success of the solid culture of Pandora species on cereals.
