Relation Between Motility, Accelerated Aging and Gene Expression in Selected Drosophila Strains under Hypergravity Conditions

Abstract

Motility and aging in Drosophila have proven to be highly modified under altered gravity conditions (both in space and ground simulation facilities). In order to find out how closely connected they are, five strains with altered geotactic response or survival rates were selected and exposed to an altered gravity environment of 2g. By analysing the different motile and behavioural patterns and the median survival rates, we show that altered gravity leads to changes in motility, which will have a negative impact on the flies' survival. Previous results show a differential gene expression between sessile samples and adults and confirm that environmentally-conditioned behavioural patterns constrain flies' gene expression and life span. Therefore, hypergravity is considered an environmental stress factor and strains that do not respond to this new environment experience an increment in motility, which is the major cause for the observed increased mortality also under microgravity conditions. The neutral-geotaxis selected strain (strain M) showed the most severe phenotype, unable to respond to variations in the gravitational field. Alternatively, the opposite phenotype was observed in positive-geotaxis and long-life selected flies (strains B and L, respectively), suggesting that these populations are less sensitive to alterations in the gravitational load. We conclude that the behavioural response has a greater contribution to aging than the modified energy consumption in altered gravity environments.

Ground-Based Facilities for Simulation of Microgravity: Organism-Specific Recommendations for Their Use, and Recommended Terminology

“…Furthermore, for a particular strain, the influence of microgravity was found to be dependent on the age and gender of the flies and closely related with environmental conditions (Serrano et al, 2010;Serrano et al, 2012). Consequently, not only the facility and environmental condition but also the biological state (i.e., age, gender, strain) of the organisms should be carefully considered in the experiment design.…”

Genome-Wide Gene Expression in relation to Age in Large Laboratory Cohorts ofDrosophila melanogaster

“…As described above, C. elegans has been used for such research, for example, McCarroll et al [ 3 ]. Moreover, relevant studies have been conducted using D. melanogaster specific body parts [ 10 ], quantitative trait loci [ 11 ], specific tissues [ 12 ], overexpression of a heat shock protein [ 13 ], different developmental stages [ 14 ], selection for mated longevity [ 15 ], low dose radiation [ 16 ], selection for starvation resistance [ 17 ], response to heat stress, oxidative stress, and ionizing radiation [ 18 ], lines selected for late-age fertility and life span [ 19 ], selection under hypergravity [ 20 ], and selection for postponed senescence [ 21 ]. The present study extends this category of aging research on D. melanogaster by relatively frequent sampling during the adult fly aging process.…”

Alterations in the activity and sleep of Drosophila melanogaster under simulated microgravity

“…In our previous study 36 mentioned above, we used Canton-S males under LD condition only, to provide the feasibility of RPM, and found that Canton-S males were more sensitive to short-time simulated microgravity, and the alterations of activity and sleep were different between day and night, suggesting the light might play an important role. In addition, some studies have also shown that the influence of microgravity on motility varies among different strains, ages, and sexes 23 , 37 , 60 , but the reasons remain speculative. Therefore, we think that to reveal the effects of simulated microgravity on activity and sleep of fruit fly might also need to carefully consider the influences of other key elements such as light conditions, strains, and sexes.…”

“…Drosophila melanogaster is a convenient model for in-orbit research due to its small body size, fast reproduction, short life cycle, and relatively low life support requirements 23 , 37 , 38 . A number of studies have shown that fruit flies are sensitive to the space environment, which results in certain physiological and genetic responses 22 , 34 , 38 – 42 .…”