Protopopova Marina V, Pavlichenko Vasiliy V, Luckenbach Till
Siberian Institute of Plant Physiology and Biochemistry SB RAS, Irkutsk, Russia.
Faculty of Biology and Soil Sciences, Irkutsk State University, Irkutsk, Russia.
PeerJ. 2020 Mar 9;8:e8635. doi: 10.7717/peerj.8635. eCollection 2020.
The induction of cellular stress response systems, heat shock protein /Hsp70 and multixenobiotic transporter , by cadmium chloride (CdCl) was explored in amphipod species with different stress adaptation strategies from the Lake Baikal area. Based on the lethal concentrations (LC) of CdCl, the sensitivities of the different species to CdCl were ranked (24 hr LC50 in mg/L CdCl (mean/95% confidence interval)): (1.7/1.3-2.4) < (2.9/2.1-4.0) < (5.7/3.8-8.7) < (18.1/12.4-26.6). Conjugated dienes, indicating lipid peroxidation, were significantly increased after 24 hr exposures to 5 mg/L CdCl only in the more CdCl-sensitive species and . Upon treatment with 0.54 to 5.8 mg/L CdCl for 1, 6 and 24 hrs, transcript levels were generally more increased after the longer exposure times and in the more CdCl-sensitive species. Relating the CdCl exposure concentrations to LCx values revealed that across the species the increases of transcript levels were comparatively low (up to 2.6-fold) at CdCl concentrations ≤LC50. Relative transcript levels were maximally increased in by 5 mg/L CdCl ( LC70) at 24 hrs (9.1-fold increase above the respective control). When was exposed to 5 mg/L CdCl ( LC90) for 24 hrs, the increase in was in comparison to considerably less pronounced (3.0-fold increase in levels relative to control). Upon exposure of amphipods to 5 mg/L CdCl, increases in Hsp70 protein levels compared to untreated controls were highest in at 1 and 6 hrs (5 mg/L CdCl LC70) and in at 24 hrs (5 mg/L CdCl LC45). Thus, when the fold increases in Hsp70 protein levels in the different amphipod species were related to the respective species-specific LCx values a similar bell-shaped trend as for transcript levels was seen across the species. Transcript levels of in CdClexposed individuals of the different amphipod species varied up to 4.7-fold in relation to the respective controls. In contrast to /Hsp70, transcripts in CdCl exposed individuals of the different amphipod species did not indicate similar levels of induction of at equal LCx levels across the species. Induction of and genes and Hsp70 proteins by CdCl in the lethal concentration range shows that these cellular responses are rather insensitive to CdCl stress in the examined amphipod species. Furthermore, the increase of expression of these cellular defense systems at such high stress levels suggests that induction of these genes is not related to the maintenance of normal metabolism but to mitigation of the effects of severe toxic stress.
在来自贝加尔湖地区具有不同应激适应策略的双足类物种中，研究了氯化镉（CdCl）对细胞应激反应系统、热休克蛋白/Hsp70和多异生物质转运蛋白的诱导作用。根据CdCl的致死浓度（LC），对不同物种对CdCl的敏感性进行了排序（24小时LC50，单位为mg/L CdCl（平均值/95%置信区间））：（1.7/1.3 - 2.4）<（2.9/2.1 - 4.0）<（5.7/3.8 - 8.7）<（18.1/12.4 - 26.6）。仅在对CdCl更敏感的物种和中，暴露于5 mg/L CdCl 24小时后，表明脂质过氧化的共轭二烯显著增加。在用0.54至5.8 mg/L CdCl处理1、6和24小时后，转录水平通常在暴露时间较长且对CdCl更敏感的物种中增加得更多。将CdCl暴露浓度与LCx值相关联发现，在所有物种中，当CdCl浓度≤LC50时，转录水平的增加相对较低（高达2.6倍）。在24小时时，5 mg/L CdCl（LC70）使中的相对转录水平最大增加（比各自对照增加9.1倍）。当暴露于5 mg/L CdCl（LC90）24小时时，与相比，中的增加明显不那么显著（水平相对于对照增加3.0倍）。将双足类动物暴露于5 mg/L CdCl后，与未处理的对照相比，Hsp70蛋白水平的增加在1和6小时时在中最高（5 mg/L CdCl LC70），在24小时时在中最高（5 mg/L CdCl LC45）。因此，当不同双足类物种中Hsp70蛋白水平的增加倍数与各自物种特异性的LCx值相关时，在所有物种中观察到与转录水平类似的钟形趋势。不同双足类物种中暴露于CdCl的个体中的转录水平相对于各自对照变化高达4.7倍。与/Hsp70相反，不同双足类物种中暴露于CdCl的个体中的转录本在相同LCx水平下并未显示出跨物种相似的诱导水平。在致死浓度范围内，CdCl对和基因以及Hsp70蛋白的诱导表明，这些细胞反应在所研究的双足类物种中对CdCl应激相当不敏感。此外，这些细胞防御系统在如此高的应激水平下表达的增加表明，这些基因的诱导与维持正常代谢无关，而是与减轻严重毒性应激的影响有关。
