掺氮碳量子点对光合细菌生长过程的影响

Effect of nitrogen-doped carbon quantum dots on the growth of photosynthetic bacteria

以柠檬酸为碳源?乙二胺为修饰剂,一步水热合成了掺氮碳量子点(N-CQDs).通过分析光合色素?蛋白质和丙二醛等生理指标,研究了N-CQDs对光合细菌Rhodopseudomonas acidophila生长的影响.结果表明N-CQDs抑制了R.acidophila的生长并呈现浓度-效应关系;光合色素分析表明N-CQDs促使R.acidophila菌体的类胡萝卜素含量提高,菌绿素含量降低;光谱分析表明N-CQDs导致了胞内物质(如光合色素?蛋白质等)的泄漏.N-CQDs较强的光诱导电子转移能力导致R.acidophila培养体系中产生过量自由基,自由基引发一系列脂质过氧化反应,进而导致生物膜的破裂?物质外泄和细菌衰亡.光照下N-CQDs对R.acidophila表现出较高的毒性.研究结果对于认识N-CQDs的光致毒性及其生态环境效应具有一定的参考价值.

Nitrogen-doped carbon quantum dots(N-CQDs)were formed by one-step hydrothermal synthesis,using citric acid as carbon source and ethylene diamine as modifier in this study.The effects of N-CQDs on the growth of photosynthetic bacteria Rhodopseudomonas acidophila were investigated by analyzing the physiological indexes of photosynthetic pigment,protein and malondialdehyde.The results showed that N-CQDs inhibited the growth of R.acidophila and showed a concentration-effect relationship.Additionally,N-CQDs increased the content of carotenoid in R.acidophila while it decreased the content of bacteriochlorophyll.Furthermore,spectra analysis results showed that N-CQDs led to the leakage of intracellular sbustances such as photosynthetic pigment and protein.The strong light-induced electron transfer ability of N-CQDs resulted in excessive free radicals in the culture system of R.acidophila,which led to a series of lipid peroxidation reactions,which in turn led to the rupture of biofilms,material leakage and bacterial death.N-CQDs had a high toxicity on R.acidophila under light.The results of this study are valuable for understanding the phototoxicity and ecological effects of N-CQDs.