The dissertation is devoted to the study of biochemical processes in Chlorella vulgaris Вeij. after adding selenium, zinc and chromium compounds in aquaculture in order to develop effective ways of regulating metabolism in the direction of lipid metabolism activation, production of lipids when these trace elements will be added into their composition, and assessment of the biological activity of the obtained lipid compounds (with added elements) in normal conditions and in rats with experimental diabetes mellitus (ED).
It was revealed that the Selenium concentration separately (Se (IV) 10.0 mg/dm3) and with Zinc (Zn (II) 5.0 mg/dm3) or with Chromium (Cr (III) 5.0 mg/dm3) and the duration of culture incubation in the altered medium for 7 days is the most optimal. The process of accumulation and inclusion of Selenium, Zinc and Chromium into cells and lipids of Ch. vulgaris has a concentration and time dependence. Under these conditions, compared to the control, there was both an increase of the total amount of lipids in the chlorella composition, and a redistribution of the content of their separate classes: an increase of phospholipids (PL) and a decrease of diacylglycerols (DAG) by the action of Se separately; an increase of DAG, non-esterified fatty acids (NEFA) and PL and a decrease of triacylglycerols (TAG) after adding Se + Zn; an increase of TAG and NEFA and a decrease of DAG and PL by the action of Se + Zn. There was also a general increase in the percentage of unsaturated fatty acids C 18:1 and C 18:2 and a decrease in the proportion of saturated C 16:0, whereas the content of C 18:0 was within the control values. It was found that the general trend in Ch. vulgaris is a decrease in the incorporation of Н14 СО-3 into TAG and an increase in PL and NEFA. The intensity of C-oleate incorporation by the action of selenium, zinc and chromium salts shows an increase in PL and TAG biosynthesis in Ch. vulgaris, and a decrease in DAG and partly NEFA biosynthesis. High glycerol-3-phosphatacyltransferase activity in Ch. vulgaris correlated with maintaining the cells' relative stationary TAG and PL content.
The investigation of the energy metabolism of Ch. vulgaris showed that under the experimental conditions (Se (IV) 10.0 mg/dm3 and Se (IV) 10.0 mg/dm3 + Cr (III) 5.0 mg /dm3) the increase in the activity of CO and SDH in algae was consistent with a decrease in the activity of GDG- (NAD(P)H), which confirms the determining role of TCA and ETC in energy production processes in algae cells. At the same time, under the influence of Se (IV) in a dose of 10.0 mg/dm3 + Zn (II) 5.0 mg/dm3, there was a decrease in the activity of SDH and CO, which was accompanied by an increase in the activity of GDH and the ratio of NADH-GDH/NADPH-GDH. It is also found that in the restructuring of the antioxidant status of Ch vulgaris cells under the action of all variants increases the role of GPx and reduces the participation of CAT and SOD.
The absence of a negative effect of Selenium, Zinc or Chromium on the genetic apparatus of Ch. vulgaris - fragment analysis using ISSR and IRAP markers showed the 38.5% level of polymorphism. The genetic distances according to Jacquard (Dj) for control were: for the action of Selenium – 0.232, for the action of Selenium and Zinc - 0.206, for the action of Selenium and Chromium – 0.300. Microscopic and morphometric studies revealed a thickening of the algal cell membrane by 1.5–2.2 times and during the change in activity of total ATP-ase in the range of 5.2% - 28.4%.
The analysis of Ch. vulgaris cultivation indicators in the constructed bioreactor shows the possibility of growing algae culture in a long-term mode with an average productivity of about 110.5 ± 4.1 mg of dry weight/dm3 (content of carbohydrates 60 mg, protein - 35 mg, lipids - 12 mg/dm3). At the same time, under the influence of solar insolation, the average biomass productivity in the steady state was about 212.4 ± 18.1 mg of dry biomass/dm3 and with the lipid content of 19.02 ± 0.4 mg/dm3.
The obtained results open the possibility for the usage of biologically active additives made from chlorella and enriched with trace elements Se (IV), Zn (II) and Cr (III), as promising therapeutic and prophylactic substances, which will contribute to the successful functioning of the antioxidant system, maintainance of energetic and metabolic homeostasis in the body for better correction of pathological processes.
