Hasan Md Mahbub, Todoriki Setsuko, Miyanoshita Akihiro, Imamura Taro, Hayashi Toru
Laboratory for Stored Product Protection, Department of Zoology, Rajshahi University, Rajshahi 6205, Bangladesh.
J Econ Entomol. 2006 Oct;99(5):1912-9. doi: 10.1093/jee/99.5.1912.
The soft-electron beam (low-energy electrons) and gamma-radiation sensitivities of phosphine-resistant (PHR) and -susceptible (PHS) strains of adults lesser grain borer Rhyzopertha dominica (F.) were studied, with particular reference to DNA damage assessed using single-cell electrophoresis (comet assay). Results showed that mortality in adult R. dominica varied significantly between both PHR and PHS strains. Adults of the PHR strain were found to be more tolerant toward soft-electron and gamma radiation than adults of the PHS strain. Studies on the longevity of strains showed that mean survival time and dose rate were highly correlated with both strains and treatments. Results also showed that adults of the PHR strain lived longer than adults of PHS strain for both treatments. Radiation sensitivity indices, however, decreased as radiation dose increased in both strains. Analysis of DNA damage, after 40- and 160-Gy gamma radiation, was carried out using cells obtained from both strains. Gamma-irradiated adults of both strains showed typical DNA fragmentation, compared with cells from nonirradiated adults, which showed more intact DNA. Investigations using the comet assay showed that tail length, moment, olive-tail moment, percentage of tail DNA, and percentage of DNA damage were all greater in the PHS strain compared with the PHR strain and the control insects. Results also showed that DNA damage remained at a constant level for up to 24 h after irradiation. The results have been discussed in relation to the observed strain differences in radiation sensitivity and resistance to phosphine.
研究了谷蠹成虫磷化氢抗性（PHR）和敏感（PHS）品系对软电子束（低能电子）和γ辐射的敏感性，特别参考了使用单细胞电泳（彗星试验）评估的DNA损伤情况。结果表明，谷蠹成虫的死亡率在PHR和PHS品系之间存在显著差异。发现PHR品系的成虫比PHS品系的成虫对软电子和γ辐射更具耐受性。对品系寿命的研究表明，平均存活时间和剂量率与品系和处理方式高度相关。结果还表明，两种处理下PHR品系的成虫比PHS品系的成虫寿命更长。然而，辐射敏感性指数在两个品系中均随着辐射剂量的增加而降低。使用从两个品系获得的细胞对40 Gy和160 Gyγ辐射后的DNA损伤进行了分析。与未辐照成虫的细胞相比，两个品系经γ辐照的成虫均显示出典型的DNA片段化，未辐照成虫的细胞显示出更多完整的DNA。使用彗星试验的研究表明，与PHR品系和对照昆虫相比，PHS品系的尾长、矩、橄榄尾矩、尾DNA百分比和DNA损伤百分比均更高。结果还表明，辐照后长达24小时DNA损伤保持在恒定水平。已结合观察到的品系在辐射敏感性和对磷化氢抗性方面的差异对结果进行了讨论。
