Investigation on microgravity-driven effects to facilitate space exploration: focus on human cell lines and cyanobacteria

Microgravity or weightlessness is one of the predominant problems for human in space and due to the increasing interest in this field it is necessary to study what concerning space on earth. The random positioning machine allows precisely to simulate the conditions of microgravity on earth. In this thesis the effect of microgravity and the changing occurring under extreme conditions in different cell lines both human and cyanobacteria, was investigated. Specifically, the investigation was focused on the changes that occur in the structure and function of erythrocyte, neuroblastoma cells and cyanobacteria under simulated microgravity, compared to terrestrial conditions, at different time points using different techniques. When exposed to simulated microgravity erythrocytes showed morphological changes, a constant increase in reactive oxygen species and in malondialde-hyde levels, a significant reduction in total antioxidant capacity and in total glutathione concentra-tion, over times. Experiments performed to evaluate the lipid profile of erythrocyte membranes showed an upregulation in several membrane phosphocholines as: PC16:0_16:0, PC 33:5, PC18:2_18:2, PC 15:1_20:4 and SM d42:1. In addition, experiments carried out with cyanobacteria A. platensis showed a higher biomass productivity in a medium containing up to 40 %vol of Martian Medium compared with the Zarrouk’s Medium a classical cultivation medium using the random po-sitioning machine both with and without the addiction of CO2. Moreover, experiments in simulated microgravity condition were also performed using two different models of neuroblastoma cell lines, the SH-SY5Y and M17 3K-SNCA, where cells showed a rapidly increase in -synuclein aggregation with an increasing level of reactive oxygen species that are counterbalanced by high level of cata-lase. In conclusion, there has been an increasing interest towards the understanding of the biochem-ical and structural alterations that occur when biosystems, and in particular cells, are maintained in zero-gravity or microgravity conditions. Microgravity can be used as a model for different patholo-gies and studies related to the investigation on human health during space exploration. This interest is certainly stimulated by the increasing human activities on the international space station (ISS) and in foreseeable long-term space missions.