Checkpoint and physiological apoptosis in germ cells proceeds normally in spaceflown Caenorhabditis elegans

Abstract

It is important for human life in space to study the effects of environmental factors during spaceflight on a number of physiological phenomena. Apoptosis plays important roles in development and tissue homeostasis in metazoans. In this study, we have analyzed apoptotic activity in germ cells of the nematode C. elegans, following spaceflight. Comparison of the number of cell corpses in wild type or ced-1 mutants, grown under either ground or spaceflight conditions, showed that both pachytene-checkpoint apoptosis and physiological apoptosis in germ cells occurred normally under spaceflight conditions. In addition, the expression levels of the checkpoint and apoptosis related genes are comparable between spaceflight and ground conditions. This is the first report documenting the occurrence of checkpoint apoptosis in the space environment and suggests that metazoans, including humans, would be able to eliminate cells that have failed to repair DNA lesions introduced by cosmic radiation during spaceflight.

Analysis of the Effect of Space Radiations on the Nematode, <i> Caenorhabditis elegans </i>, through the Simulated Space Radiation

“…We also confirmed the same results as Nelson found: protons and gamma rays have different effects on C. elegans gene pattern through GO analysis. Short term (10 d) exposure to actual space radiation and microgravity on ICE-FIRST revealed that apoptosis proceeds normally [9] and that no significant increase in the rate of mutation occurs [10]. Decreased levels of myogenic transcription factor were observed [27].…”

“…The effects on nematodes that were grown for 3 -4 generations in CeMM media and in space for 10 d were analyzed. In this experiment, space-faring animals underwent normal development, apoptosis [9], and DNA repair [10], but experienced altered muscle development [11]. Because it can sustain a high degree of radiation damage, C. elegans can be used as a potential biological dosimeter [12].…”

The effect of high strength static magnetic fields and ionizing radiation on gene expression and DNA damage in Caenorhabditis elegans

“…For exposures below 40 Gy, most damage to the meiotic nuclei of C. elegans can be repaired by the meiotic homologous recombination system [Takanami et al, 2000[Takanami et al, , 2003. Apoptotic cell corpses in the pachytene region of dissected gonads were visualized by differential interference contrast microscopy [Deng et al, 2004;Higashitani et al, 2005;Sugimoto et al, 2006].…”

Hypergravity hinders axonal development of motor neurons inCaenorhabditis elegans

“…Moreover, because worms are easy to handle, studies using C. elegans have been conducted in space. Worms survive and grow well in space, and many functions of the worms are normal (Higashitani et al, 2005; Szewczyk et al, 2008; Zhao et al, 2006). Muscle gene expression is slightly altered in space (Higashibata et al, 2006), as well as markers for aging (Honda et al, 2012).…”