Department of Animal Physiology and Ecotoxicology, University of Silesia in Katowice, Bankowa 9, 40-007 Katowice, Poland.
Department of Animal Physiology and Ecotoxicology, University of Silesia in Katowice, Bankowa 9, 40-007 Katowice, Poland.
Ecotoxicol Environ Saf. 2018 Dec 30;166:138-145. doi: 10.1016/j.ecoenv.2018.09.016. Epub 2018 Sep 25.
The growth and development of living organisms is programmed in genes, but exogenous factors (e.g. cadmium) may modulate endogenous information. Heavy metals may disturb physiological functions and accumulate in the tissues. The insects under prolonged heavy metal stress show some modifications in their metabolism management. The aim of this study was to compare the reproduction and development between individuals of S. exigua from the strain, exposed over 130 generations to sublethal concentration of cadmium (44 mg Cd/kg dry weight of larval diet), and the individuals from the control strain, both additionally exposed to different concentration of cadmium (22-704 mg Cd/kg dry weight of larval diet). The exposure to various cadmium concentrations in the diet revealed survival difference between the cadmium and the control animals at the larvae stage. The differences between adults were not evident. The telomere length (responsible for the duration of a lifespan) in the cadmium strain was shorter in the females than in the males and the individuals from the control strain. TERF1 gene expression (indirectly responsible for the telomere length) was higher in the individuals from the cadmium strain 24 hrs after eclosion. The significant reduction in the larvae body mass was observed in both strains, when the metal concentration was equal to or higher than 264 mg/kg dry weight of larval diet. The EC50 values (defined as of body mass loss), calculated 48 hours after cadmium exposure of individuals from control and cadmium strains, were respectively 632 and 725 mg Cd/kg dry weight of diet. However, some difference in reproduction (the total number of eggs laid and the oviposition time) between the strains appeared only in the groups fed on the uncontaminated diet. The control females laid almost two times more eggs than those from the cadmium strain, and the control ones had more than two times longer oviposition time than the females from the cadmium strain. The fluctuation was also noted in the size of eggs and the hatching success on the following days when both strains were compared, while the hatching success was higher for the insects from the cadmium strain. In conclusion, the insects from the cadmium strain are more resistant to cadmium contamination, as it is evidenced by the EC50 parameter. However, the females from the cadmium strain start laying eggs statistically later, have shorter telomeres and slightly reduced TERF1 gene expression, but hutching success in the strain is significantly higher when compared with the control individuals.
生物体的生长和发育是由基因编程的，但外源性因素（如镉）可能会调节内源性信息。重金属可能会干扰生理功能并在组织中积累。在长期重金属胁迫下，昆虫的新陈代谢管理会发生一些变化。本研究的目的是比较暴露于亚致死浓度镉（44mgCd/kg 幼虫饮食干重）超过 130 代的 S.exigua 个体与对照品系个体之间的繁殖和发育，以及同时暴露于不同浓度镉（22-704mgCd/kg 幼虫饮食干重）的个体。饮食中不同浓度的镉暴露导致幼虫阶段镉和对照动物的存活率存在差异。成虫之间的差异不明显。镉株的端粒长度（决定寿命长短）在雌性中比在雄性中和对照株的个体更短。TERF1 基因表达（间接负责端粒长度）在刚羽化 24 小时后镉株个体中更高。当金属浓度等于或高于 264mg/kg 幼虫饮食干重时，两种品系的幼虫体重均显著减轻。在暴露于镉的个体中，控制株和镉株的 EC50 值（定义为体重损失）分别为 632 和 725mgCd/kg 饮食干重。然而，在未受污染饮食喂养的组中，仅在两种品系之间观察到繁殖（产卵总数和产卵时间）的一些差异。对照品系的雌性产卵数几乎是镉株的两倍，而对照品系的产卵时间是镉株的两倍多。当比较两种品系时，还注意到了卵的大小波动和随后几天的孵化成功率，而镉株的孵化成功率更高。总之，与 EC50 参数相比，镉株的昆虫对镉污染更具抵抗力。然而，镉株的雌性产卵时间统计上较晚，端粒较短，TERF1 基因表达略有降低，但与对照个体相比，该品系的孵化成功率显著提高。
