[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the t...[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the test material, the field control efficiencies of four pesticides including PrGV · Bt WP 1 000 times dilution, NPV · Bt SC 750 times dilution, 0.5% azadirachtin EC 750 times dilution, and 0.3% matrine AS 500 times dilution against P. rapae were studied, and their impacts on yield and planting benefits of Chinese cabbage were also determined. Using foliar spray method, the pesticides were sprayed for the first time when the second or third instar larvae of P. rapae first occurred in fields, and sprayed for the second time with the interval of 15 d. The fields sprayed with beta-cypermethrin EC （organic chemical pesticide） and water were set as control. [ Result] NPV · Bt SC 750 times dilution had the best effect after spraying for two times： the control efficiency against P. rapae at 15 d after spraying was 90.11% ; the damage rate of Chinese cabbage was only 0.21%, while the commodity rate reached 100% ; compared with chemical pesticide spraying, the commodity yield （177 262.5 kg/hm2 ） and the income after deducting spraying cost （48 858.5 yuan/hm2 ） were increased by 14.7% and 13.75%, respectively. [ Conclusion] Although biological pesticides are more expensive, they have long persistence and good control effect, resulting in green and safe Chinese cabbage with high commodity rate and yield, and higher eventual economic benefit after deducting spraying cost.展开更多
[Objective]The paper was to study the field control effects of different formulae of plant extracts against cabbage worm Pieris rapae,and to provide a basis for promotion and application of insecticides in production....[Objective]The paper was to study the field control effects of different formulae of plant extracts against cabbage worm Pieris rapae,and to provide a basis for promotion and application of insecticides in production.[Method]With the leaching solution of radix anemones rivularis,Artemisia carvifolia and Nicotiana rustica,and lime and salt water as the materials,field efficacy test was conducted for consecutive two years.[Method]When the mass ratios of radix anemones rivularis mother liquid,A.carvifolia mother liquid,N.rustica mother liquid,lime water and salt water were 4:2:2:1:1:6,4:2:0:1:1:8,4:0:2:1:1:8 and 0:4:2:1:1:8,the control effects were 82.7%-89.8%,38.3%-42.0%,41.0%-45.4%and 52.9%-56.4%,respectively.The insecticide showed the best control effect when the mass ratio of radix anemones rivularis mother liquid,A.carvifolia mother liquid,N.rustica mother liquid,lime water and salt water was 4:2:2:1:1:6.[Conclusion]The optimal formula has good control effect against P.rapae,and the technology has obtained national invention patent.展开更多
To better understand the origination and evolution of lef-3 gene from baculovirus genome and determine the relationships between various viruses at molecular level, late expression factor 3 gene （lef-3） fragments of...To better understand the origination and evolution of lef-3 gene from baculovirus genome and determine the relationships between various viruses at molecular level, late expression factor 3 gene （lef-3） fragments of Pieris rapae granulovirus were obtained through conventional PCR method and sequenced after cloned into T-vector. Then, bioinformatics analysis on lef-3 gene and its encoding sequences were conducted by using bid-softs. Four mutations were appeared in the ORF of cloned lef-3 gene, which did not alter the characteristics of amino acids. It was inferred that PiraGV LEF-3 protein contained 399 amino acids, the molecular weight of which was 3.99 kD. Prediction of the LEF-3 advanced structure and homology comparison between other LEF-3 from various baculoviruses showed that the lef-3 gene might encode the single-stranded DNA-binding protein. The result of BLAST revealed that the lef-3 gene only existed in Lepidoptera host for the baculovirus genome, and the evolution analysis illustrated that lef-3 gene could be divided into 3 groups including one granulovirus （GV） group and 2 nucleopolyhedrovirus （NPV） groups. The selection pressure analysis of GV lef-3 gene coding region showed that the majority of lef-3 genes performed negative selection, while the Ka/Ks differed from different lef-3 gene, to some extent, which also performed positive selection. The origination analysis revealed that lef-3 gene of baculovirus might derive from bacteria. The lef-3 gene of PiraGV was cloned successfully and the possible patterns of origination and evolution were speculated through bioinformatics analysis.展开更多
Field efficacy trials of different pesticides against Pieris rapae and Plutella xylostella showed that seven pesticides had certain control effects against P.rapae and P. xylostella. 240 g/L Chlorfenapyr SC had the mo...Field efficacy trials of different pesticides against Pieris rapae and Plutella xylostella showed that seven pesticides had certain control effects against P.rapae and P. xylostella. 240 g/L Chlorfenapyr SC had the most ideal control effect,with quick effect and long persistence,and the control effects against P. rapae and P. xylostella were 91. 96% and 95. 73% after application for 7 d,respectively. 25% Thiamethoxam WDG 3 000 times dilution had the poorest control effect,and quick effect and persistence were not ideal; the control effects against P. rapae and P. xylostella were 49. 21% and 57. 20% after application for 7 d,respectively. The remaining pesticides had good control effect against both P. rapae and P. xylostella,with certain persistence. Slight injury such as yellowing tender leaves appeared in the area treated with 50% thiocyclam SP,although the injury was reversible,it was still not recommended to use; no other treatments had adverse effects on growth of cabbage.展开更多
A molecular genetic map of Chinese cabbage was constructed with a 102 recombinant inbred (RI) population from a cross of two cultivated Chinese cabbage lines 177 and 276, using AFLP and RAPD markers. 352 markers inclu...A molecular genetic map of Chinese cabbage was constructed with a 102 recombinant inbred (RI) population from a cross of two cultivated Chinese cabbage lines 177 and 276, using AFLP and RAPD markers. 352 markers including 265 AFLP markers and 87 RAPD markers were integrated into 17 linkage groups. It covered a total of 2 665. 7 cM with an average interval of 7. 6 cM. AFLP marker is efficient for map construction while it easily forms clusters to cause big gaps in map. A total of 13.92 % abnormal segregation markers distributed in the map. The molecular genetic map is fundamental for gene localization, comparative genomics, and QTL mapping of important agronomic traits.展开更多
We conducted plant growth experiments in microbe-free vermiculite to study the effects of four types of fermented seaweed liquid fertilizer (SLF) made from nori (Pyropia yezoensis) seaweed on the germination, plant gr...We conducted plant growth experiments in microbe-free vermiculite to study the effects of four types of fermented seaweed liquid fertilizer (SLF) made from nori (Pyropia yezoensis) seaweed on the germination, plant growth characteristics, SPAD value, and nutrient content and uptake of komatsuna (Brassica rapa L. var. wakana komatsuna). The four types of fermented nori SLF used in this study were prepared by anaerobic fermentation of unwashed nori (SLF1), aerobic fermentation of unwashed nori (SLF2), anaerobic fermentation of washed nori (SLF3), and aerobic fermentation of washed nori (SLF4). Komatsuna seeds treated with 200-, 300-, and 400-fold dilutions of SLFs exhibited improved relative germination ratios (RGRs) at 3 and 4 days after sowing (DAS). At 4 DAS, the RGRs of seeds treated with 10-, 100-, 200-, 300-, and 400-fold SLF dilutions showed no differential effect. Seeds treated with undiluted SLFs did not germinate by 4 DAS. SLF1 may promote komatsuna seed germination. The nitrogen (N), calcium, magnesium, sodium (Na), and iodine (I) contents of plants treated with SLF1 were significantly increased relative to plants treated with the other SLFs. Moreover, the I and Na contents of plants were significantly increased by foliar spray application of different dilutions of SLF1. However, SLF treatment markedly reduced the shoot dry weight compared with 1/2-strength modified Hoagland nutrient (MHN) solution, although the same amounts of N and K were applied. SPAD values of the plants treated with SLFs were significantly higher than those of plants treated with MHN. Foliar treatment with SLFs had no significant effect on plant growth, SPAD value, or uptake of nutrients (except Na) relative to the control, but the I content was increased. Plants treated with SLF1 and SLF2 exhibited the highest Na uptake. Foliar spray treatments with SLF1 resulted in the highest I contents in plants. Based on our results, SLF1 is suitable for use as a liquid fertilizer to promote germination and increase nutrient content in komatsuna. These results need to be followed up in soil experiments in the presence of microbes in the rhizosphere.展开更多
The kinetic parameters of partially purified phenoloxidase （PO, EC. 1.14.18.1） from the 5th instar larvae of Pieris rapae （Lepidoptera） were determined, using L-3, 4- dihydroxyphenylalanine （L-DOPA） as substrate...The kinetic parameters of partially purified phenoloxidase （PO, EC. 1.14.18.1） from the 5th instar larvae of Pieris rapae （Lepidoptera） were determined, using L-3, 4- dihydroxyphenylalanine （L-DOPA） as substrate. The optimal pH and temperature of the enzyme for the oxidation of L-DOPA were determined to be at pH 7.0 and at 42℃, respectively. The enzyme was stable between pH 6.5 and 7.4 and at temperatures lower than 37℃. At pH 6.8 and 37℃, the Michaelis constant （Kin） and maximal velocity （V） of the enzyme for the oxidation of L-DOPA were determined to be 0.80 mmol/L and 1.84 μmol/ L/min, respectively. Tetra-hexylresorcinol and 4-dodecylresorcinol effectively inhibited activity of phenoloxidase and this inhibition was reversible and competitive, with the IC50 of 1.50 and 1.12 μmol/L, respectively. The inhibition constants were estimated to be 0.50 and 0.47μmol/L, respectively.展开更多
Parasitism by the endoparasitic wasp Pteromalus puparum （Hymenoptera： Pteromalidae） by using only its associated venom, can suppress the immunal responses of Pieris rapae （Lepidoptera： Pieridae）. However, up to ...Parasitism by the endoparasitic wasp Pteromalus puparum （Hymenoptera： Pteromalidae） by using only its associated venom, can suppress the immunal responses of Pieris rapae （Lepidoptera： Pieridae）. However, up to now, current knowledge of the mech- anisms has been limited. The response of host hemocytes to parasitism was investigated using a combination of light and transmission electron microscopy （TEM）. Five hemocyte types, prohemocytes （PRs）, granulocytes （GRs）, plasmatocytes （PLs）, oenocytoids （OEs） and coagulocytes （COs）, were observed and characterized from both unparasitized and parasitized Pieris rapae pupae. Light microscopy showed that both GRs and PLs became more round and spread abnormally after parasitism, whereas the shape of other types of hemocytes remained unaffected. In addition, the size of PRs and PLs became larger while OEs became smaller. The proportion of PRs significantly increased after parasitism and that of PLs decreased by 43.9%, but there was no significant increase of GRs and OEs. TEM showed that all types of hemocytes except COs were damaged to various degrees after parasitism, especially resulting in electron opaque cytoplasm and nucleus, fewer cell organelles of rough endoplasmic reticulum, mitochondria and vesicles. Our results indicate that parasitism by P. puparum affects differential hemocyte counts and structures of host hemocytes, particularly for GRs and PLs, which may be the main cause of the parasitoid suppressing host cellular immune responses.展开更多
This report presents the cDNA cloning of a storage protein, PraAry, from Pieris rapae and investigates its expression regulated by parasitism of an endoparasitoid wasp Pteromalus puparum. The full-length eDNA of PraAr...This report presents the cDNA cloning of a storage protein, PraAry, from Pieris rapae and investigates its expression regulated by parasitism of an endoparasitoid wasp Pteromalus puparum. The full-length eDNA of PraAry is 2 270 nucleotides and contains a 2 121 nucleotide open reading frame encoding 707 amino acids with calculated molecular weights of approximately 83 kDa. Analysis of the primary protein sequence revealed that it possesses a signal peptide of 16 amino acids at the N-terminus and contains two highly conserved storage protein signature motifs. According to both phylogenetic analysis and the criteria for amino acid composition, PraAry belongs to the subfamily of arylphorin-type storage protein （1.42% methionine and 18.82% aromatic amino acids）. Reverse transcription- polymerase chain reaction analysis indicated that the transcriptional level of PraAry mRNA in P. rapae pupae fat body is inducible in response to parasitism by P. puparum.展开更多
Polyphenol oxidase （PPO） is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO a metalloenzyme oxidase...Polyphenol oxidase （PPO） is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO a metalloenzyme oxidase, catalyzes the oxidation of o-diphenol to o-quinone. The present paper describes the effects of benzaldehyde and its p-substituted derivatives on the activity of PPO from the fifth instar of Pieris rapae L. PPO from the fifth instar of Pieris rapae L. was purified using ammonium sulfate fractionation and chromatography on Sephadex G-100. The enzyme kinetics was characterized using L-3,4-dihydroxyphenylalanine （L-DOPA） as substrate. The results show that benzaldehyde, phydroxybenzaldehyde, p-chlorobenzaldehyde, and p-cyanobenzaldehyde can inhibit the PPO activity for the oxidation of L-DOPA. The inhibitor concentration leading to 50% activity lost, IC50, was estimated to be 5.90, 5.62, 2.83, and 2.91 mmol/L for the four tested inhibitors, respectively. Kinetic analyses show that the inhibitory effects of these compounds are reversible. Benzaldehyde, phydroxybenzaldehyde, and p-chlorobenzaldehyde are noncompetitive inhibitors while p-cyanobenzaldehyde is a mixed-type inhibitor. The inhibition constants were determined for all four inhibitors. p-chlorobenzaldehyde and p-cyanobenzaldehyde were more potent inhibitors than the other compounds. These results provide a basis for developing PPO inhibition-based pesticides.展开更多
基金Supported by Science and Technology Research and Development Program of Chengde City in 2011(201121167)
文摘[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the test material, the field control efficiencies of four pesticides including PrGV · Bt WP 1 000 times dilution, NPV · Bt SC 750 times dilution, 0.5% azadirachtin EC 750 times dilution, and 0.3% matrine AS 500 times dilution against P. rapae were studied, and their impacts on yield and planting benefits of Chinese cabbage were also determined. Using foliar spray method, the pesticides were sprayed for the first time when the second or third instar larvae of P. rapae first occurred in fields, and sprayed for the second time with the interval of 15 d. The fields sprayed with beta-cypermethrin EC （organic chemical pesticide） and water were set as control. [ Result] NPV · Bt SC 750 times dilution had the best effect after spraying for two times： the control efficiency against P. rapae at 15 d after spraying was 90.11% ; the damage rate of Chinese cabbage was only 0.21%, while the commodity rate reached 100% ; compared with chemical pesticide spraying, the commodity yield （177 262.5 kg/hm2 ） and the income after deducting spraying cost （48 858.5 yuan/hm2 ） were increased by 14.7% and 13.75%, respectively. [ Conclusion] Although biological pesticides are more expensive, they have long persistence and good control effect, resulting in green and safe Chinese cabbage with high commodity rate and yield, and higher eventual economic benefit after deducting spraying cost.
基金Supported by National Staple Vegetable Industrial Technical System(CARS-23-G37)Vegetable Agricultural Industry Research System of Yunnan Province(2017KJTX0011)Key Science and Technology Project of Yunnan Province "Key Green Technology Research and Integrated Demonstration of Major Exported Vegetables in Yunnan Province"(2019ZG001)
文摘[Objective]The paper was to study the field control effects of different formulae of plant extracts against cabbage worm Pieris rapae,and to provide a basis for promotion and application of insecticides in production.[Method]With the leaching solution of radix anemones rivularis,Artemisia carvifolia and Nicotiana rustica,and lime and salt water as the materials,field efficacy test was conducted for consecutive two years.[Method]When the mass ratios of radix anemones rivularis mother liquid,A.carvifolia mother liquid,N.rustica mother liquid,lime water and salt water were 4:2:2:1:1:6,4:2:0:1:1:8,4:0:2:1:1:8 and 0:4:2:1:1:8,the control effects were 82.7%-89.8%,38.3%-42.0%,41.0%-45.4%and 52.9%-56.4%,respectively.The insecticide showed the best control effect when the mass ratio of radix anemones rivularis mother liquid,A.carvifolia mother liquid,N.rustica mother liquid,lime water and salt water was 4:2:2:1:1:6.[Conclusion]The optimal formula has good control effect against P.rapae,and the technology has obtained national invention patent.
基金supported by the National High Technology Research and Development Program of China(2006AA10A118)
文摘To better understand the origination and evolution of lef-3 gene from baculovirus genome and determine the relationships between various viruses at molecular level, late expression factor 3 gene （lef-3） fragments of Pieris rapae granulovirus were obtained through conventional PCR method and sequenced after cloned into T-vector. Then, bioinformatics analysis on lef-3 gene and its encoding sequences were conducted by using bid-softs. Four mutations were appeared in the ORF of cloned lef-3 gene, which did not alter the characteristics of amino acids. It was inferred that PiraGV LEF-3 protein contained 399 amino acids, the molecular weight of which was 3.99 kD. Prediction of the LEF-3 advanced structure and homology comparison between other LEF-3 from various baculoviruses showed that the lef-3 gene might encode the single-stranded DNA-binding protein. The result of BLAST revealed that the lef-3 gene only existed in Lepidoptera host for the baculovirus genome, and the evolution analysis illustrated that lef-3 gene could be divided into 3 groups including one granulovirus （GV） group and 2 nucleopolyhedrovirus （NPV） groups. The selection pressure analysis of GV lef-3 gene coding region showed that the majority of lef-3 genes performed negative selection, while the Ka/Ks differed from different lef-3 gene, to some extent, which also performed positive selection. The origination analysis revealed that lef-3 gene of baculovirus might derive from bacteria. The lef-3 gene of PiraGV was cloned successfully and the possible patterns of origination and evolution were speculated through bioinformatics analysis.
基金Supported by Special Project on Development of Agricultural Industry in Hangzhou City"Integration and Demonstration of Key Technology for Green Control against Pests and Diseases of Vegetables"
文摘Field efficacy trials of different pesticides against Pieris rapae and Plutella xylostella showed that seven pesticides had certain control effects against P.rapae and P. xylostella. 240 g/L Chlorfenapyr SC had the most ideal control effect,with quick effect and long persistence,and the control effects against P. rapae and P. xylostella were 91. 96% and 95. 73% after application for 7 d,respectively. 25% Thiamethoxam WDG 3 000 times dilution had the poorest control effect,and quick effect and persistence were not ideal; the control effects against P. rapae and P. xylostella were 49. 21% and 57. 20% after application for 7 d,respectively. The remaining pesticides had good control effect against both P. rapae and P. xylostella,with certain persistence. Slight injury such as yellowing tender leaves appeared in the area treated with 50% thiocyclam SP,although the injury was reversible,it was still not recommended to use; no other treatments had adverse effects on growth of cabbage.
文摘A molecular genetic map of Chinese cabbage was constructed with a 102 recombinant inbred (RI) population from a cross of two cultivated Chinese cabbage lines 177 and 276, using AFLP and RAPD markers. 352 markers including 265 AFLP markers and 87 RAPD markers were integrated into 17 linkage groups. It covered a total of 2 665. 7 cM with an average interval of 7. 6 cM. AFLP marker is efficient for map construction while it easily forms clusters to cause big gaps in map. A total of 13.92 % abnormal segregation markers distributed in the map. The molecular genetic map is fundamental for gene localization, comparative genomics, and QTL mapping of important agronomic traits.
文摘We conducted plant growth experiments in microbe-free vermiculite to study the effects of four types of fermented seaweed liquid fertilizer (SLF) made from nori (Pyropia yezoensis) seaweed on the germination, plant growth characteristics, SPAD value, and nutrient content and uptake of komatsuna (Brassica rapa L. var. wakana komatsuna). The four types of fermented nori SLF used in this study were prepared by anaerobic fermentation of unwashed nori (SLF1), aerobic fermentation of unwashed nori (SLF2), anaerobic fermentation of washed nori (SLF3), and aerobic fermentation of washed nori (SLF4). Komatsuna seeds treated with 200-, 300-, and 400-fold dilutions of SLFs exhibited improved relative germination ratios (RGRs) at 3 and 4 days after sowing (DAS). At 4 DAS, the RGRs of seeds treated with 10-, 100-, 200-, 300-, and 400-fold SLF dilutions showed no differential effect. Seeds treated with undiluted SLFs did not germinate by 4 DAS. SLF1 may promote komatsuna seed germination. The nitrogen (N), calcium, magnesium, sodium (Na), and iodine (I) contents of plants treated with SLF1 were significantly increased relative to plants treated with the other SLFs. Moreover, the I and Na contents of plants were significantly increased by foliar spray application of different dilutions of SLF1. However, SLF treatment markedly reduced the shoot dry weight compared with 1/2-strength modified Hoagland nutrient (MHN) solution, although the same amounts of N and K were applied. SPAD values of the plants treated with SLFs were significantly higher than those of plants treated with MHN. Foliar treatment with SLFs had no significant effect on plant growth, SPAD value, or uptake of nutrients (except Na) relative to the control, but the I content was increased. Plants treated with SLF1 and SLF2 exhibited the highest Na uptake. Foliar spray treatments with SLF1 resulted in the highest I contents in plants. Based on our results, SLF1 is suitable for use as a liquid fertilizer to promote germination and increase nutrient content in komatsuna. These results need to be followed up in soil experiments in the presence of microbes in the rhizosphere.
基金Acknowledgments The present investigation was supported in part by grant N0. 30270887, 30571237 of the National Natural Science Foundation of China for W. C. Luo.
文摘The kinetic parameters of partially purified phenoloxidase （PO, EC. 1.14.18.1） from the 5th instar larvae of Pieris rapae （Lepidoptera） were determined, using L-3, 4- dihydroxyphenylalanine （L-DOPA） as substrate. The optimal pH and temperature of the enzyme for the oxidation of L-DOPA were determined to be at pH 7.0 and at 42℃, respectively. The enzyme was stable between pH 6.5 and 7.4 and at temperatures lower than 37℃. At pH 6.8 and 37℃, the Michaelis constant （Kin） and maximal velocity （V） of the enzyme for the oxidation of L-DOPA were determined to be 0.80 mmol/L and 1.84 μmol/ L/min, respectively. Tetra-hexylresorcinol and 4-dodecylresorcinol effectively inhibited activity of phenoloxidase and this inhibition was reversible and competitive, with the IC50 of 1.50 and 1.12 μmol/L, respectively. The inhibition constants were estimated to be 0.50 and 0.47μmol/L, respectively.
文摘Parasitism by the endoparasitic wasp Pteromalus puparum （Hymenoptera： Pteromalidae） by using only its associated venom, can suppress the immunal responses of Pieris rapae （Lepidoptera： Pieridae）. However, up to now, current knowledge of the mech- anisms has been limited. The response of host hemocytes to parasitism was investigated using a combination of light and transmission electron microscopy （TEM）. Five hemocyte types, prohemocytes （PRs）, granulocytes （GRs）, plasmatocytes （PLs）, oenocytoids （OEs） and coagulocytes （COs）, were observed and characterized from both unparasitized and parasitized Pieris rapae pupae. Light microscopy showed that both GRs and PLs became more round and spread abnormally after parasitism, whereas the shape of other types of hemocytes remained unaffected. In addition, the size of PRs and PLs became larger while OEs became smaller. The proportion of PRs significantly increased after parasitism and that of PLs decreased by 43.9%, but there was no significant increase of GRs and OEs. TEM showed that all types of hemocytes except COs were damaged to various degrees after parasitism, especially resulting in electron opaque cytoplasm and nucleus, fewer cell organelles of rough endoplasmic reticulum, mitochondria and vesicles. Our results indicate that parasitism by P. puparum affects differential hemocyte counts and structures of host hemocytes, particularly for GRs and PLs, which may be the main cause of the parasitoid suppressing host cellular immune responses.
文摘This report presents the cDNA cloning of a storage protein, PraAry, from Pieris rapae and investigates its expression regulated by parasitism of an endoparasitoid wasp Pteromalus puparum. The full-length eDNA of PraAry is 2 270 nucleotides and contains a 2 121 nucleotide open reading frame encoding 707 amino acids with calculated molecular weights of approximately 83 kDa. Analysis of the primary protein sequence revealed that it possesses a signal peptide of 16 amino acids at the N-terminus and contains two highly conserved storage protein signature motifs. According to both phylogenetic analysis and the criteria for amino acid composition, PraAry belongs to the subfamily of arylphorin-type storage protein （1.42% methionine and 18.82% aromatic amino acids）. Reverse transcription- polymerase chain reaction analysis indicated that the transcriptional level of PraAry mRNA in P. rapae pupae fat body is inducible in response to parasitism by P. puparum.
基金Supported by the Science and Technology Foundation of Fujian Province (No. 2004N002)the National Natural Science Foundation of China (No. 30570408)
文摘Polyphenol oxidase （PPO） is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO a metalloenzyme oxidase, catalyzes the oxidation of o-diphenol to o-quinone. The present paper describes the effects of benzaldehyde and its p-substituted derivatives on the activity of PPO from the fifth instar of Pieris rapae L. PPO from the fifth instar of Pieris rapae L. was purified using ammonium sulfate fractionation and chromatography on Sephadex G-100. The enzyme kinetics was characterized using L-3,4-dihydroxyphenylalanine （L-DOPA） as substrate. The results show that benzaldehyde, phydroxybenzaldehyde, p-chlorobenzaldehyde, and p-cyanobenzaldehyde can inhibit the PPO activity for the oxidation of L-DOPA. The inhibitor concentration leading to 50% activity lost, IC50, was estimated to be 5.90, 5.62, 2.83, and 2.91 mmol/L for the four tested inhibitors, respectively. Kinetic analyses show that the inhibitory effects of these compounds are reversible. Benzaldehyde, phydroxybenzaldehyde, and p-chlorobenzaldehyde are noncompetitive inhibitors while p-cyanobenzaldehyde is a mixed-type inhibitor. The inhibition constants were determined for all four inhibitors. p-chlorobenzaldehyde and p-cyanobenzaldehyde were more potent inhibitors than the other compounds. These results provide a basis for developing PPO inhibition-based pesticides.
