Nowadays, emerging nanotechnologies are intensively implemented in the various fields of applied biology. Detonation nanodiamonds (ND) are particles with size of approximately 5 nm, which have crystal structure of a diamond. In order to improve solubility in aqueous solution, ND surface is functionalized with hydrophilic functional groups that bring new physical and chemical properties. It has recently been shown that functionalized ND possess oxidase-, peroxidase-, and catalase-like activity in aqueous solutions [1], which open the possibility to exploit ND for cell protection in algal biotechnology. Nutrient deprivation is often used in biotechnology to switch cell metabolism from growth towards production of lipids (biofuel), molecular hydrogen, or carotenoids (astaxanthin). But this stimulus also causes overgeneration of reactive oxygen species thus reducing photosynthetic activity, culture viability, and the yield of valuable products. In the present work, we investigated the protection effects of ND functionalized with carboxyl group in the model green alga Chlamydomonas reinhardtii (cell-wall deficient strain CC-400) exposed to the oxidative stress. In order to induce oxidative stress, cell cultures were either exposed to strong light (photoinhibition), sulfur deficiency, or treated with methyl viologen or dye Rose Bengal to generate superoxide anion radicals or singlet oxygen, respectively. Photosynthetic capacity was assessed by recording the chlorophyll fluorescence parameter FV/FM which refers to the maximum efficiency of PS II photochemistry. We showed that the addition of ND to algal suspension results in apparent PS II protection under oxidative stress. The highest extent of ND based protection of the PS II activity was observed under the stress induced by methyl viologen, indicating particular efficiency of ND for deactivation of the superoxide anion radical and related reactive oxygen species in the cell. The obtained results allowed us to conclude that ND can serve to improve photosynthetic stability and performance in the algal cell upon oxidative stress thus facilitating culture viability. References: 1. T. M. Chen, X. M. Tian, L. Huang, J. Xiao and G. W. Yang, Nanoscale, 2017, 9, 15673-15684
Photoprotective effect of nanodiamonds in green microalgae Chlamydomonas reinhardtii
Maya D Lambreva;
2019
Abstract
Nowadays, emerging nanotechnologies are intensively implemented in the various fields of applied biology. Detonation nanodiamonds (ND) are particles with size of approximately 5 nm, which have crystal structure of a diamond. In order to improve solubility in aqueous solution, ND surface is functionalized with hydrophilic functional groups that bring new physical and chemical properties. It has recently been shown that functionalized ND possess oxidase-, peroxidase-, and catalase-like activity in aqueous solutions [1], which open the possibility to exploit ND for cell protection in algal biotechnology. Nutrient deprivation is often used in biotechnology to switch cell metabolism from growth towards production of lipids (biofuel), molecular hydrogen, or carotenoids (astaxanthin). But this stimulus also causes overgeneration of reactive oxygen species thus reducing photosynthetic activity, culture viability, and the yield of valuable products. In the present work, we investigated the protection effects of ND functionalized with carboxyl group in the model green alga Chlamydomonas reinhardtii (cell-wall deficient strain CC-400) exposed to the oxidative stress. In order to induce oxidative stress, cell cultures were either exposed to strong light (photoinhibition), sulfur deficiency, or treated with methyl viologen or dye Rose Bengal to generate superoxide anion radicals or singlet oxygen, respectively. Photosynthetic capacity was assessed by recording the chlorophyll fluorescence parameter FV/FM which refers to the maximum efficiency of PS II photochemistry. We showed that the addition of ND to algal suspension results in apparent PS II protection under oxidative stress. The highest extent of ND based protection of the PS II activity was observed under the stress induced by methyl viologen, indicating particular efficiency of ND for deactivation of the superoxide anion radical and related reactive oxygen species in the cell. The obtained results allowed us to conclude that ND can serve to improve photosynthetic stability and performance in the algal cell upon oxidative stress thus facilitating culture viability. References: 1. T. M. Chen, X. M. Tian, L. Huang, J. Xiao and G. W. Yang, Nanoscale, 2017, 9, 15673-15684I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
