Response of extreme haloarchaeon Haloarcula argentinensis RR10 to simulated microgravity in clinorotation

Abstract

Gravity is the fundamental force that may have operated during the evolution of life on Earth. It is thus important to understand as to what the effects of gravity are on cellular life. The studies related to effect of microgravity on cells may provide greater insights in understanding of how the physical force of gravity shaped life on Earth. The present study focuses on a unique group of organisms called the Haloarchaea, which are known for their extreme resistance to survive in stress-induced environments. The aim of the present investigation was to study the effect of simulated microgravity on physiological response of extremely halophilic archaeon, Haloarcula argentinensis RR10, under slow clinorotation. The growth kinetics of the archaeon in microgravity was studied using the Baryani model and the viable and apoptotic cells were assessed using propidium iodide fluorescent microscopic studies. The physiological mechanism of adaptation was activation of ‘salt-in’ strategy by intracellular sequestration of sodium ions as detected by EDAX. The organism upregulated the production of ribosomal proteins in simulated microgravity as evidenced by Matrix-assisted laser desorption ionization Time of flight–Mass Spectrophotometry. Simulated microgravity altered the antibiotic susceptibility of the haloarchaeon and it developed resistance to Augmentin, Norfloxacin, Tobramycin and Cefoperazone, rendering it a multidrug resistant strain. The presence of antibiotic efflux pump was detected in the haloarchaeon and it also enhanced production of protective carotenoid pigment in simulated microgravity. The present study is presumably the first report of physiological response of H. argentinensis RR10 in microgravity simulated under slow clinorotation.

How the space environment influences organisms: an astrobiological perspective and review

“…A significant number of studies have investigated the growth response of different microorganisms, including bacteria, fungi, archaea and microalgae, to real and simulated microgravity conditions. Studies with Escherichia coli (Bouloc and D'Ari, 1991; Thévenet et al ., 1996; Kacena et al ., 1997; 1999b; Brown et al ., 2002; Benoit and Klaus, 2005; Tucker et al ., 2007; Arunasri et al ., 2013; Tirumalai et al ., 2017), Bacillus subtilis (Kacena et al ., 1997; 1999b), Salmonella typhimurium (Wilson et al ., 2002a), Pseudomonas aeruginosa (England et al ., 2003; Kim et al ., 2013a; 2013b), Staphylococcus (Rosado et al ., 2010), Streptococcus (Allen et al ., 2007; Orsini et al ., 2017), Streptomyces (Fang et al ., 1997c; 2000), Saccharomyces cerevisiae (Purevdorj-Gage et al ., 2006; van Mulders et al ., 2011), Candida albicans (Altenburg et al ., 2008; Crabbé et al ., 2013; Jiang et al ., 2014), Deinococcus radiodurans (Ott et al ., 2019), Haloarchaea (Dornmayr-Pfaffenhuemer et al ., 2011; Thombre et al ., 2017), Euglena (Häder et al ., 2005; Nasir et al ., 2014; Krüger et al ., 2019), Chlamydomonas (Yoshimura et al ., 2003; Häder et al ., 2005), etc., have been conducted. Most studies have reported reduced lag phase and increased cell population across several bacterial species in the space environment (Benoit and Klaus, 2007; Horneck et al ., 2010; Huang et al ., 2018).…”

“…An increase in resistance to antibiotics and various stresses, such as acid, thermal and osmotic, is also observed in a real and simulated space environment (Leys et al ., 2004; Klaus and Howard, 2006; Horneck et al ., 2010; Taylor, 2015; Thombre et al ., 2017; Aunins et al ., 2018). Higher concentrations of antibiotics are required to inhibit bacterial growth in microgravity.…”

“…This is probably due to the lower transport rate (mass transport is limited to diffusion) and changes in cell proliferation, membrane permeability, rate and morphology (Klaus et al ., 1997, 2004; Kacena and Todd, 1999; Sieber et al ., 2014; Zea et al ., 2016, 2017; Kohn et al ., 2017; Aunins et al ., 2018; Kohn and Hauslage, 2019). In a study with the halophilic archaeon, Haloarcula argentinensis under simulated microgravity condition (clinostat), an increase in the activity of antibiotic efflux pumps resulting in the development of multi-drug resistance to antibiotics, such as augmentin, norfloxacin, tobramycin and cefoperazone was observed (Thombre et al ., 2017). Studies have also indicated the involvement of global regulators ( hfq and rpoS ) in cross-resistance to antibiotics in Salmonella and E. coli under microgravity conditions (Wilson et al ., 2002a; Lynch et al ., 2004; Horneck et al ., 2010).…”

“…thioredoxin, catalase, peroxiredoxin, thiol peroxidase, sulfoxide reductase MsrA) in space-exposed Bacillus spores, E. coli , Rhodospirillum rubrum and S. typhimurium , indicating the up-regulation of antioxidant defence mechanisms to cope with the space-induced oxidative damage occurring during long-term spaceflight (Wilson et al ., 2008; Mastroleo et al ., 2009; Nicholson et al ., 2012; Vaishampayan et al ., 2012). Increased synthesis of protective carotenoids has been reported in simulated-microgravity-exposed H. argentinensis against the oxidative damage caused by the harmful effects of stress (Thombre et al ., 2017). Studies also show that cells activate pathways similar to those induced during osmotic stress and produce osmoprotective compounds (e.g.…”

Survival of Extremotolerant Bacteria from the Mukundpura Meteorite Impact Crater

“…Control consisted of incubation of the culture at static conditions (1 g) (Thombre et al, 2017b). After every 24 h, one microfuge tube was withdrawn, and growth was measured in terms of absorbance at 600 nm (Thombre et al, 2016c) with a UV-Vis spectrophotometer (UV-1800, Shimadzu, Japan).…”