This study was designed to explore the possibility of using ascitic mouse sarcoma cell line (S180) to validate the mouse tumor cell attachment assay for developmental toxicants, and to test the inhibitory effects of v...This study was designed to explore the possibility of using ascitic mouse sarcoma cell line (S180) to validate the mouse tumor cell attachment assay for developmental toxicants, and to test the inhibitory effects of various developmental toxicants. The results showed that 2 of 3 developmental toxicants under consideration, sodium pentobarbital and ethanol, significantly inhibited S180cells attachment to Concanavalin A-coaed surfaces. Inhibition was dependent on concentration, and the IC50 (the concentration tha reduced attachment by 50% ), of these 2 chemicals was 1.2×10-3mol/L and 1 .0 mol/L, respectively. Anoher developmental toxiant, hydmiortisone, did not show inhibitory activity. Two non-developmental toxicants, sodium chloride and glycine were also tested and these did not decrease attachment rates. The main results reported here were generally sindlar to those obtained with ascitic mouse ovdrian tumor cells as a model. Therefore, this study added further evidence to the conclusion that cell specificity does not lindt attachment inhibition to Con A-coated surfaces, so S180 cell may serve as an altemative cell model, especially when other cell lines are unavailable. Furthermore, after optimal validation, it can be suggested that an S180 cell attachment assay may be a candidate for a series of assays to detect developmental toxicants.展开更多
The phenyl and methyl phenyl free radicals,formed in the oxidation-hydrolysis process of N’-acyl-N-phenylhydrazine, have been studied by ESR spectrometry.It was found that the free radical is the chief cause which pr...The phenyl and methyl phenyl free radicals,formed in the oxidation-hydrolysis process of N’-acyl-N-phenylhydrazine, have been studied by ESR spectrometry.It was found that the free radical is the chief cause which produces the feed-back inhibition effect in the hydrazine-promoted infectious development of silver halide.展开更多
The two-spotted spider mite,Tetranychus urticae Koch,is one of the most harmful pests in many agroecosystems worldwide.To effectively manage this pest,there is an urgent need to develop novel bio-active acaricides tha...The two-spotted spider mite,Tetranychus urticae Koch,is one of the most harmful pests in many agroecosystems worldwide.To effectively manage this pest,there is an urgent need to develop novel bio-active acaricides that support integrated pest management strategies targeting T.urticae.In this study,we explored the acaricidal effects of xenocoumacin 1 (Xcn1) on T.urticae and its predator Neoseiulus californicus using the highly puri?ed compound.Xcn1 was extracted and purified from the cell-free supernatant of the Xenorhabdus nematophila CB6 mutant constructed by the easy promoter activated compound identi?cation (easyPACId) method.When the concentration of Xcn1 exceeded 100μg mL~(–1),the survival rate of spider mite adults declined to below 40%and the fecundity was decreased by 80%at six days post-application.At concentrations of 25 and 50μg mL~(–1),Xcn1 signi?cantly impeded spider mite development by inhibiting the molt.However,neither concentration had any adverse effects on the survival or reproduction of the predatory mite N.californicus.The results from laboratory and semi-?eld experiments consistently demonstrated the effectiveness of the antimicrobial metabolite Xcn1 in controlling pest mites at both the molecular and physiological levels.Our study offers a promising possibility that combines the compatible biocontrol agents of Xcn1 and predatory mites for integrated pest mite control.展开更多
文摘This study was designed to explore the possibility of using ascitic mouse sarcoma cell line (S180) to validate the mouse tumor cell attachment assay for developmental toxicants, and to test the inhibitory effects of various developmental toxicants. The results showed that 2 of 3 developmental toxicants under consideration, sodium pentobarbital and ethanol, significantly inhibited S180cells attachment to Concanavalin A-coaed surfaces. Inhibition was dependent on concentration, and the IC50 (the concentration tha reduced attachment by 50% ), of these 2 chemicals was 1.2×10-3mol/L and 1 .0 mol/L, respectively. Anoher developmental toxiant, hydmiortisone, did not show inhibitory activity. Two non-developmental toxicants, sodium chloride and glycine were also tested and these did not decrease attachment rates. The main results reported here were generally sindlar to those obtained with ascitic mouse ovdrian tumor cells as a model. Therefore, this study added further evidence to the conclusion that cell specificity does not lindt attachment inhibition to Con A-coated surfaces, so S180 cell may serve as an altemative cell model, especially when other cell lines are unavailable. Furthermore, after optimal validation, it can be suggested that an S180 cell attachment assay may be a candidate for a series of assays to detect developmental toxicants.
文摘The phenyl and methyl phenyl free radicals,formed in the oxidation-hydrolysis process of N’-acyl-N-phenylhydrazine, have been studied by ESR spectrometry.It was found that the free radical is the chief cause which produces the feed-back inhibition effect in the hydrazine-promoted infectious development of silver halide.
基金supported by the National Natural Science Foundation of China(32070402)the Beijing Natural Science Foundation,China(6222052)。
文摘The two-spotted spider mite,Tetranychus urticae Koch,is one of the most harmful pests in many agroecosystems worldwide.To effectively manage this pest,there is an urgent need to develop novel bio-active acaricides that support integrated pest management strategies targeting T.urticae.In this study,we explored the acaricidal effects of xenocoumacin 1 (Xcn1) on T.urticae and its predator Neoseiulus californicus using the highly puri?ed compound.Xcn1 was extracted and purified from the cell-free supernatant of the Xenorhabdus nematophila CB6 mutant constructed by the easy promoter activated compound identi?cation (easyPACId) method.When the concentration of Xcn1 exceeded 100μg mL~(–1),the survival rate of spider mite adults declined to below 40%and the fecundity was decreased by 80%at six days post-application.At concentrations of 25 and 50μg mL~(–1),Xcn1 signi?cantly impeded spider mite development by inhibiting the molt.However,neither concentration had any adverse effects on the survival or reproduction of the predatory mite N.californicus.The results from laboratory and semi-?eld experiments consistently demonstrated the effectiveness of the antimicrobial metabolite Xcn1 in controlling pest mites at both the molecular and physiological levels.Our study offers a promising possibility that combines the compatible biocontrol agents of Xcn1 and predatory mites for integrated pest mite control.
