The acute and chronic toxic effects of bifenthrin on Daphnia magna were studied. The results showed that 24 h-EC 50 , 48 h-LC 50 and 96 h-LC 50 of bifenthrin on D. magna were 3.24, 12.40 and 1.40 μg/L r...The acute and chronic toxic effects of bifenthrin on Daphnia magna were studied. The results showed that 24 h-EC 50 , 48 h-LC 50 and 96 h-LC 50 of bifenthrin on D. magna were 3.24, 12.40 and 1.40 μg/L respectively. And the LOEC and NOEC of bifenthrin were 0.02 and 0.004 μg/L respectively. The recovery test of bifenthrin on Daphnia magna was presented. Daphnia magna(F 0 generation) were exposed during 21 d to different bifenthrin concentrations. Offspring(animals from the first and third brood: F 1(1st) and F 1(3rd), respectively) were transferred to a free pesticide medium during a 21 d recovery period. In this recovery study, survival, growth, reproduction(mean total young per female, onset of reproduction and number broods per female) and the intrinsic rate of natural increase (r) were assessed as parameters. Reproduction such as number of young per female as well as length was still reduced in F 1(1st) generation daphnids from parentals(F 0) exposed to the bifenthrin. However F 1(3rd) individuals from parentals exposed to pesticide concentrations were able to restore reproduction when a recovery period of 21 d was allowed, but the length of F 1(3rd) from parentals exposed to the 0.5 and 0.75 μg/L bifenthrin concentration was still significantly effected(P<0.05).展开更多
PR-39 is a porcine antimicrobial pep- tide that plays an important role in the innate defense mechanism. We produced monoclonal antibodies （MAbs） against PR-39 by fusing mouse myeloma ceils with lymph node cells fro...PR-39 is a porcine antimicrobial pep- tide that plays an important role in the innate defense mechanism. We produced monoclonal antibodies （MAbs） against PR-39 by fusing mouse myeloma ceils with lymph node cells from BALB/c mice immu- nized with the reactive site sequence PR-11 of PR-39. Furthermore, we investigated the effect of lactoferrin on PR-39 gene levels and peptide concentrations in cultural supernatants of bone marrow granulocytes by RT-PCR and the competitive inhibition ELISA meth- od established in this study. Two hybridomas 3H5 and 5H7 were selected for developing ascites and con- tained MAbs against PR-11, which were used for screening the specificity to PR-39 by competitive inhi- bition ELISA. We found that MAbs were successfully produced against PR-11 and the MAbs had a strong reaction with PR-39 excreted by porcine marrow gran-ulocytes. The ascites had a relatively high titer and the purified MAbs were determined as IgG1. Incubation with 10 or 100 ixg/mL lactoferrin significantly in- creased （ P 〈 0.05 ） PR-39 mRNA levels in bone mar- row granulocytes after 3 h and 6 h, but 1000 pog/mL lactoferrin reduced （ P 〈 0.05） PR-39 mRNA expres- sion after 3 h and 6 h compared with control （ no lact- oferrin added）. The relative concentrations of PR-39 in supernatant secreted by marrow granulocytes were significantly increased by 1000 p,g/mL lactoferrin af- ter both 3 h and 6 h. These findings suggest a regula- tory role of lactoferrin for the antimicrobial peptide PR-39 in marrow cells in vitro. It is possible that the regulation of antimicrobial peptide PR-39 expression may be one of the protective mechanisms of lacto- ferrin in pigs.展开更多
文摘The acute and chronic toxic effects of bifenthrin on Daphnia magna were studied. The results showed that 24 h-EC 50 , 48 h-LC 50 and 96 h-LC 50 of bifenthrin on D. magna were 3.24, 12.40 and 1.40 μg/L respectively. And the LOEC and NOEC of bifenthrin were 0.02 and 0.004 μg/L respectively. The recovery test of bifenthrin on Daphnia magna was presented. Daphnia magna(F 0 generation) were exposed during 21 d to different bifenthrin concentrations. Offspring(animals from the first and third brood: F 1(1st) and F 1(3rd), respectively) were transferred to a free pesticide medium during a 21 d recovery period. In this recovery study, survival, growth, reproduction(mean total young per female, onset of reproduction and number broods per female) and the intrinsic rate of natural increase (r) were assessed as parameters. Reproduction such as number of young per female as well as length was still reduced in F 1(1st) generation daphnids from parentals(F 0) exposed to the bifenthrin. However F 1(3rd) individuals from parentals exposed to pesticide concentrations were able to restore reproduction when a recovery period of 21 d was allowed, but the length of F 1(3rd) from parentals exposed to the 0.5 and 0.75 μg/L bifenthrin concentration was still significantly effected(P<0.05).
文摘PR-39 is a porcine antimicrobial pep- tide that plays an important role in the innate defense mechanism. We produced monoclonal antibodies （MAbs） against PR-39 by fusing mouse myeloma ceils with lymph node cells from BALB/c mice immu- nized with the reactive site sequence PR-11 of PR-39. Furthermore, we investigated the effect of lactoferrin on PR-39 gene levels and peptide concentrations in cultural supernatants of bone marrow granulocytes by RT-PCR and the competitive inhibition ELISA meth- od established in this study. Two hybridomas 3H5 and 5H7 were selected for developing ascites and con- tained MAbs against PR-11, which were used for screening the specificity to PR-39 by competitive inhi- bition ELISA. We found that MAbs were successfully produced against PR-11 and the MAbs had a strong reaction with PR-39 excreted by porcine marrow gran-ulocytes. The ascites had a relatively high titer and the purified MAbs were determined as IgG1. Incubation with 10 or 100 ixg/mL lactoferrin significantly in- creased （ P 〈 0.05 ） PR-39 mRNA levels in bone mar- row granulocytes after 3 h and 6 h, but 1000 pog/mL lactoferrin reduced （ P 〈 0.05） PR-39 mRNA expres- sion after 3 h and 6 h compared with control （ no lact- oferrin added）. The relative concentrations of PR-39 in supernatant secreted by marrow granulocytes were significantly increased by 1000 p,g/mL lactoferrin af- ter both 3 h and 6 h. These findings suggest a regula- tory role of lactoferrin for the antimicrobial peptide PR-39 in marrow cells in vitro. It is possible that the regulation of antimicrobial peptide PR-39 expression may be one of the protective mechanisms of lacto- ferrin in pigs.
