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Insecticide-mediated up-regulation of cytochrome P450 genes in the red flour beetle (Tribolium castaneum).

Liang X, Xiao D, He Y, Yao J, Zhu G, Zhu KY - Int J Mol Sci (2015)

Bottom Line: Reverse transcription quantitative PCR (RT-qPCR) revealed that CYP4G7 and CYP345A1 can be significantly up-regulated by cypermethrin (1.97- and 2.06-fold, respectively), permethrin (2.00- and 2.03-fold) and lambda-cyhalothrin (1.73- and 1.81-fold), whereas CYP4BR3 and CYP345A1 can be significantly up-regulated by imidacloprid (1.99- and 1.83-fold) when 20-day larvae were exposed to each of these insecticides at the concentration of LC20 for 24 h.Our study demonstrated that up-regulation of these CYP genes was rapid and only required low concentrations of insecticides, and the up-regulation not only depended on the CYP genes but also the type of insecticides.Our results along with those from previous studies also indicated that there were no specific patterns for predicting the up-regulation of specific CYP gene families based on the insecticide classification.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029, China. liangxiaozju@126.com.

ABSTRACT
Some cytochrome P450 (CYP) genes are known for their rapid up-regulation in response to insecticide exposures in insects. To date, however, limited information is available with respect to the relationships among the insecticide type, insecticide concentration, exposure duration and the up-regulated CYP genes. In this study, we examined the transcriptional response of eight selected CYP genes, including CYP4G7, CYP4Q4, CYP4BR3, CYP12H1, CYP6BK11, CYP9D4, CYP9Z5 and CYP345A1, to each of four insecticides in the red flour beetle, Tribolium castaneum. Reverse transcription quantitative PCR (RT-qPCR) revealed that CYP4G7 and CYP345A1 can be significantly up-regulated by cypermethrin (1.97- and 2.06-fold, respectively), permethrin (2.00- and 2.03-fold) and lambda-cyhalothrin (1.73- and 1.81-fold), whereas CYP4BR3 and CYP345A1 can be significantly up-regulated by imidacloprid (1.99- and 1.83-fold) when 20-day larvae were exposed to each of these insecticides at the concentration of LC20 for 24 h. Our studies also showed that similar levels of up-regulation can be achieved for CYP4G7, CYP4BR3 and CYP345A1 by cypermethrin, permethrin, lambda-cyhalothrin or imidacloprid with approximately one fourth of LC20 in 6 h. Our study demonstrated that up-regulation of these CYP genes was rapid and only required low concentrations of insecticides, and the up-regulation not only depended on the CYP genes but also the type of insecticides. Our results along with those from previous studies also indicated that there were no specific patterns for predicting the up-regulation of specific CYP gene families based on the insecticide classification.

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Cypermethrin concentration and time dependent up-regulation of CYP4G7 and CYP345A1 in 20-day larvae. Controls were normalized as 1.0, and the relative transcript levels of CYP genes were calculated based on their corresponding controls. (A) Cypermethrin concentration dependent up-regulation as measured at 2 and 0.5 μg/mL with the exposure time of 24 h. Different letters above the standard error bars indicate significant differences based on the one-way ANOVA followed by Tukey’s HSD multiple comparison test (p < 0.05); (B) Time dependent up-regulation of CYP4G7 by cypermethrin (0.5 μg/mL) as measured at 6, 12, 24 and 48 h; and (C) Time dependent up-regulation of CYP345A1 by cypermethrin (0.5 μg/mL) as measured at 6, 12, 24 and 48 h. Dash lines represent relative transcript level of the control (larvae treated with the insecticide solvent only) as 1.0. Statistical analysis was conducted to compare the expression levels between the control and the insecticide-treated insects within the same time duration by using Student’s t test. Asterisk above the standard error bars indicates significant difference whereas NS indicates no significant difference.
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ijms-16-02078-f004: Cypermethrin concentration and time dependent up-regulation of CYP4G7 and CYP345A1 in 20-day larvae. Controls were normalized as 1.0, and the relative transcript levels of CYP genes were calculated based on their corresponding controls. (A) Cypermethrin concentration dependent up-regulation as measured at 2 and 0.5 μg/mL with the exposure time of 24 h. Different letters above the standard error bars indicate significant differences based on the one-way ANOVA followed by Tukey’s HSD multiple comparison test (p < 0.05); (B) Time dependent up-regulation of CYP4G7 by cypermethrin (0.5 μg/mL) as measured at 6, 12, 24 and 48 h; and (C) Time dependent up-regulation of CYP345A1 by cypermethrin (0.5 μg/mL) as measured at 6, 12, 24 and 48 h. Dash lines represent relative transcript level of the control (larvae treated with the insecticide solvent only) as 1.0. Statistical analysis was conducted to compare the expression levels between the control and the insecticide-treated insects within the same time duration by using Student’s t test. Asterisk above the standard error bars indicates significant difference whereas NS indicates no significant difference.

Mentions: Because only CYP4G7 and CYP345A1 can be up-regulated by the three pyrethroids, and only CYP4BR3 and CYP345A1 can be up-regulated by imidacloprid (Figure 3), our studies on the concentration and time-dependent effect on the up-regulation focused on only three CYP genes (CYP4G7, CYP345A1 and CYP4BR3). Two different concentrations of cypermethrin, 2 μg/mL (approximate LC20) and 0.5 μg/mL (one fourth of the approximate LC20), were used to expose 20-day larvae for 24 h followed by RT-qPCR analysis of CYP4G7 and CYP345A1. The insects exposed to the two concentrations showed approximately 2-fold up-regulation in both genes, and the levels of the up-regulation did not show significant differences between the two insecticide concentrations (Figure 4A). Therefore, we used cypermethrin at 0.5 μg/mL for subsequent analyses.


Insecticide-mediated up-regulation of cytochrome P450 genes in the red flour beetle (Tribolium castaneum).

Liang X, Xiao D, He Y, Yao J, Zhu G, Zhu KY - Int J Mol Sci (2015)

Cypermethrin concentration and time dependent up-regulation of CYP4G7 and CYP345A1 in 20-day larvae. Controls were normalized as 1.0, and the relative transcript levels of CYP genes were calculated based on their corresponding controls. (A) Cypermethrin concentration dependent up-regulation as measured at 2 and 0.5 μg/mL with the exposure time of 24 h. Different letters above the standard error bars indicate significant differences based on the one-way ANOVA followed by Tukey’s HSD multiple comparison test (p < 0.05); (B) Time dependent up-regulation of CYP4G7 by cypermethrin (0.5 μg/mL) as measured at 6, 12, 24 and 48 h; and (C) Time dependent up-regulation of CYP345A1 by cypermethrin (0.5 μg/mL) as measured at 6, 12, 24 and 48 h. Dash lines represent relative transcript level of the control (larvae treated with the insecticide solvent only) as 1.0. Statistical analysis was conducted to compare the expression levels between the control and the insecticide-treated insects within the same time duration by using Student’s t test. Asterisk above the standard error bars indicates significant difference whereas NS indicates no significant difference.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4307350&req=5

ijms-16-02078-f004: Cypermethrin concentration and time dependent up-regulation of CYP4G7 and CYP345A1 in 20-day larvae. Controls were normalized as 1.0, and the relative transcript levels of CYP genes were calculated based on their corresponding controls. (A) Cypermethrin concentration dependent up-regulation as measured at 2 and 0.5 μg/mL with the exposure time of 24 h. Different letters above the standard error bars indicate significant differences based on the one-way ANOVA followed by Tukey’s HSD multiple comparison test (p < 0.05); (B) Time dependent up-regulation of CYP4G7 by cypermethrin (0.5 μg/mL) as measured at 6, 12, 24 and 48 h; and (C) Time dependent up-regulation of CYP345A1 by cypermethrin (0.5 μg/mL) as measured at 6, 12, 24 and 48 h. Dash lines represent relative transcript level of the control (larvae treated with the insecticide solvent only) as 1.0. Statistical analysis was conducted to compare the expression levels between the control and the insecticide-treated insects within the same time duration by using Student’s t test. Asterisk above the standard error bars indicates significant difference whereas NS indicates no significant difference.
Mentions: Because only CYP4G7 and CYP345A1 can be up-regulated by the three pyrethroids, and only CYP4BR3 and CYP345A1 can be up-regulated by imidacloprid (Figure 3), our studies on the concentration and time-dependent effect on the up-regulation focused on only three CYP genes (CYP4G7, CYP345A1 and CYP4BR3). Two different concentrations of cypermethrin, 2 μg/mL (approximate LC20) and 0.5 μg/mL (one fourth of the approximate LC20), were used to expose 20-day larvae for 24 h followed by RT-qPCR analysis of CYP4G7 and CYP345A1. The insects exposed to the two concentrations showed approximately 2-fold up-regulation in both genes, and the levels of the up-regulation did not show significant differences between the two insecticide concentrations (Figure 4A). Therefore, we used cypermethrin at 0.5 μg/mL for subsequent analyses.

Bottom Line: Reverse transcription quantitative PCR (RT-qPCR) revealed that CYP4G7 and CYP345A1 can be significantly up-regulated by cypermethrin (1.97- and 2.06-fold, respectively), permethrin (2.00- and 2.03-fold) and lambda-cyhalothrin (1.73- and 1.81-fold), whereas CYP4BR3 and CYP345A1 can be significantly up-regulated by imidacloprid (1.99- and 1.83-fold) when 20-day larvae were exposed to each of these insecticides at the concentration of LC20 for 24 h.Our study demonstrated that up-regulation of these CYP genes was rapid and only required low concentrations of insecticides, and the up-regulation not only depended on the CYP genes but also the type of insecticides.Our results along with those from previous studies also indicated that there were no specific patterns for predicting the up-regulation of specific CYP gene families based on the insecticide classification.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029, China. liangxiaozju@126.com.

ABSTRACT
Some cytochrome P450 (CYP) genes are known for their rapid up-regulation in response to insecticide exposures in insects. To date, however, limited information is available with respect to the relationships among the insecticide type, insecticide concentration, exposure duration and the up-regulated CYP genes. In this study, we examined the transcriptional response of eight selected CYP genes, including CYP4G7, CYP4Q4, CYP4BR3, CYP12H1, CYP6BK11, CYP9D4, CYP9Z5 and CYP345A1, to each of four insecticides in the red flour beetle, Tribolium castaneum. Reverse transcription quantitative PCR (RT-qPCR) revealed that CYP4G7 and CYP345A1 can be significantly up-regulated by cypermethrin (1.97- and 2.06-fold, respectively), permethrin (2.00- and 2.03-fold) and lambda-cyhalothrin (1.73- and 1.81-fold), whereas CYP4BR3 and CYP345A1 can be significantly up-regulated by imidacloprid (1.99- and 1.83-fold) when 20-day larvae were exposed to each of these insecticides at the concentration of LC20 for 24 h. Our studies also showed that similar levels of up-regulation can be achieved for CYP4G7, CYP4BR3 and CYP345A1 by cypermethrin, permethrin, lambda-cyhalothrin or imidacloprid with approximately one fourth of LC20 in 6 h. Our study demonstrated that up-regulation of these CYP genes was rapid and only required low concentrations of insecticides, and the up-regulation not only depended on the CYP genes but also the type of insecticides. Our results along with those from previous studies also indicated that there were no specific patterns for predicting the up-regulation of specific CYP gene families based on the insecticide classification.

Show MeSH
Related in: MedlinePlus