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CHIRIAC, Tatiana; DJUR (MAXACOVA), Svetlana; CODREANU, Svetlana; DUMBRĂVEANU, Veronica. Monitoring of the adaptive capacity of different age spirulina to oxidative stress induced by hypothermia in the presence of chemical stimulators under laboratory conditions. In: Microbial Biotechnology. Ediția 4, 11-12 octombrie 2018, Chișinău. Chișinău, Republica Moldova: Institutul de Microbiologie şi Biotehnologie, 2018, pp. 89-90. ISBN 978-9975-3178-8-7.
Ediția 4, 2018
Conferința "Microbial Biotechnology" |
Chișinău, Moldova, 11-12 octombrie 2018
In order to determine the impact of the inclusion of coordination compounds in biosynthetic activity of cyanobacterium Spirulina platensis, it was studied the change of protein content into biomass in the presence of zinc acetate under short-duration hypothermia. Hypothermic stress was induced by continued cultivation of spirulina at 40C over a period of 1, 2 and 3 hours. Spirulina has been subjected to hypothermic stress at the beginning of lag phase or one day culture, at the beginning of exponential phase or three days culture and at the end of exponential phase or six days culture. Spirulina was cultivated under optimum conditions in the presence of zinc acetate concentration of 15 mg/l. The compound has been added to mineral medium from the first day of cultivation. As a control sample, spirulina culture of the appropriate age was grown under optimal conditions (continuous illumination regime, temperature 28-320C) in the absence of chemical stimulator and in the presence of chemical stimulators. Hypothermic conditions were induced for spirulina cultivated in the absence and presence of zinc acetate. As a result, it was determined that in spirulina grown in the presence of zinc acetate on the first day of cultivation, hypothermia did not alter the protein content in the first two hours of heat stress. The reduction in the protein content has been insignificant after three hours of hypothermia. In control, reducing protein content in biomass with 16% was established after the first hour and three hours of heat stress. Spirulina culture of 3 days, in the absence of chemical stimulator, reacted to hypothermia by reducing the protein content with 28% after two hours of hypothermic stress without subsequent reduction. In the culture of spirulina grown in the presence of zinc acetate hypothermia also has altered protein content after two hours of heat stress, its value being with 24% lower compared to control sample. After three hours of hypothermia, protein content in biomass was reduced by 30% relative to control. Spirulina culture, control sample, at the end of exponential phase (day 6 of cultivation), reacting to hypothermia by reducing the protein content with 15% after the first hour of hypothermic stress and 13% - after a two-hours exposure to low temperatures. Protein content in biomass decreased with 21% after three hours of hypothermia. In spirulina grown in the presence of zinc acetate, at the age of six days, hypothermia significantly modified the protein content. Thus, after the first hour the protein content was reduced by 64%, after two hours of heat stress –with 55%. After three hours of hypothermia, reduction of protein content in biomass was lower by 44% relative to control. Therefore, the most resistant to hypothermia in terms of protein synthesis was culture at the beginning of lag phase and exponential phase. The most vulnerable age for spirulina culture was the end of exponential phase. The most significant reductions in the levels of protein were determined after the first and the third hour of hypothermia. For the experimental variant of spirulina cultivation in the presence of zinc acetate, it was established that hypothermia induced over a period of three hours did not altered the protein content in spirulina biomass at the beginning of lag phase. Spirulina, at the beginning of exponential phase, lost proteins after two hours of hypothermia. The most vulnerable has proved to be spirulina in stationary phase, which lost more than half of the protein content. Zinc acetate from cultivation medium prevented protein loss in spirulina biomass, being in adaptation period and subject to hypothermic stress. In the case of spirulina at the beginning of stationary phase, involvement of zinc acetate in biosynthetic processes has weakened the culture of spirulina which, under hypothermic conditions, lost more than half of protein content.