Contents lists available at ScienceDirect Life Sciences in Space Research journal homepage: www.elsevier.com/locate/lssr Effects of simulated microgravity on gene expression and biological phenotypes of a single generation Caenorhabditis elegans cultured on 2 different media Ling Fei Tee a , Hui-min Neoh a , Sue Mian Then b , Nor Azian Murad a , Mohd Fairos Asillam c , Mohd Helmy Hashim c , Sheila Nathan d , Rahman Jamal a, * a UKM Medical Molecular Biology Institute, Universiti Kebangsaan Malaysia, Malaysia b Department of Biomedical Sciences, The University of Nottingham, Malaysia c National Space Agency, Ministry of Science, Technology & Innovation, Malaysia d Faculty of Science & Technology, Universiti Kebangsaan Malaysia, Malaysia ARTICLE INFO Keywords: Caenorhabditis elegans Microgravity simulation Random Positioning Machine (RPM) C. elegans Maintenance Medium (CeMM) Gene expression Biological phenotype ABSTRACT Studies of multigenerational Caenorhabditis elegans exposed to long-term spaceflight have revealed expression changes of genes involved in longevity, DNA repair, and locomotion. However, results from spaceflight ex- periments are difficult to reproduce as space missions are costly and opportunities are rather limited for re- searchers. In addition, multigenerational cultures of C. elegans used in previous studies contribute to mixture of gene expression profiles from both larvae and adult worms, which were recently reported to be different. Usage of different culture media during microgravity simulation experiments might also give rise to differences in the gene expression and biological phenotypes of the worms. In this study, we investigated the effects of simulated microgravity on the gene expression and biological phenotype profiles of a single generation of C. elegans worms cultured on 2 different culture media. A desktop Random Positioning Machine (RPM) was used to simulate microgravity on the worms for approximately 52 to 54 h. Gene expression profile was analysed using the Affymetrix GeneChip® C. elegans 1.0 ST Array. Only one gene (R01H2.2) was found to be downregulated in nematode growth medium (NGM)-cultured worms exposed to simulated microgravity. On the other hand, eight genes were differentially expressed for C. elegans Maintenance Medium (CeMM)-cultured worms in microgravity; six were upregulated, while two were downregulated. Five of the upregulated genes (C07E3.15, C34H3.21, C32D5.16, F35H8.9 and C34F11.17) encode non-coding RNAs. In terms of biological phenotype, we observed that microgravity-simulated worms experienced minimal changes in terms of lifespan, locomotion and re- productive capabilities in comparison with the ground controls. Taking it all together, simulated microgravity on a single generation of C. elegans did not confer major changes to their gene expression and biological phenotype. Nevertheless, exposure of the worms to microgravity lead to higher expression of non-coding RNA genes, which may play an epigenetic role in the worms during longer terms of microgravity exposure. 1. Introduction Caenorhabditis elegans, a model organism for research in molecular biology, has been the subject of study in various spaceflight experi- ments. Phenotypically, the nematode was observed to be able to de- velop, copulate and reproduce normally in space, where no mutant phenotype was observed from worm cultures (Nelson 1994). On the other hand, space flown C. elegans were found to experience altered expressions of muscle-(hlh-1, myo-3, unc-54, egl-19, mua-3, col-97, col- 109 and col-113), DNA repair-(rad-51 and him-6) and longevity-(ins-35, glc-4, unc-17, shk-1, gar-3, F57A8.4, cha-1, dod-3 and dod-19) associated genes (Wang et al., 2008a; Then et al., 2014; Honda et al., 2012). A few concerns arise from previous C. elegans spaceflight experi- ments. Firstly, spaceflight experiment results are difficult to reproduce, as space missions are costly and rare. Secondly, the C. elegans used in most previous experimental packages were of multigenerational cul- tures consisting mixtures of larvae and adult worms. Gene expression of larvae and adult worms have been reported to be different, hence might contribute to errors in gene expression profiling experiments (Hendriks et al., 2014). Thirdly, various C. elegans culture media have http://dx.doi.org/10.1016/j.lssr.2017.06.002 Received 13 April 2017; Received in revised form 15 June 2017; Accepted 22 June 2017 * Corresponding author. E-mail addresses: hui-min@ppukm.ukm.edu.my (H.-m. Neoh), rahmanj@ppukm.ukm.edu.my (R. Jamal). Life Sciences in Space Research 15 (2017) 11–17 2214-5524/ © 2017 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved. MARK