Lack of correlation of desiccation and radiation tolerance in microorganisms from diverse extreme environments tested under anoxic conditions

Abstract

Four facultative anaerobic and two obligate anaerobic bacteria were isolated from extreme environments (deep subsurface halite mine, sulfidic anoxic spring, mineral-rich river) in the frame MASE (Mars Analogues for Space Exploration) project. The isolates were investigated under anoxic conditions for their survivability after desiccation up to 6 months and their tolerance to ionizing radiation up to 3000 Gy. The results indicated that tolerances to both stresses are strain-specific features. Yersinia intermedia MASE-LG-1 showed a high desiccation tolerance but its radiation tolerance was very low. The most radiation-tolerant strains were Buttiauxella sp. MASE-IM-9 and Halanaerobium sp. MASE-BB-1. In both cases, cultivable cells were detectable after an exposure to 3 kGy of ionizing radiation, but cells only survived desiccation for 90 and 30 days, respectively. Although a correlation between desiccation and ionizing radiation resistance has been hypothesized for some aerobic microorganisms, our data showed that there was no correlation between tolerance to desiccation and ionizing radiation, suggesting that the physiological basis of both forms of tolerances is not necessarily linked. In addition, these results indicated that facultative and obligate anaerobic organisms living in extreme environments possess varied species-specific tolerances to extremes.

Biomolecular self-assembly under extreme Martian mimetic conditions

“…However there exists no direct evidence of what its concentration may be. While it is shown that Mg(ClO4)2 can become highly bactericidal when irradiated by UV flux levels consistent with what would be expected at the Martian surface [19], or when desiccated [20], this subsurface briny water would offer an environment where these bactericidal effects would be significantly diminished. It has been shown that several organisms, such as the microorganism Halorubrum lacusprofundi isolated from Deep Lake in Antarctica, are capable of anaerobic growth in 0.04 M Mg(ClO4)2 [21,22], hence the presence of this salt alone does not eliminate the possibility for life.…”

MARSBOx: Fungal and Bacterial Endurance From a Balloon-Flown Analog Mission in the Stratosphere

“…This negative result was consistent with previous Mars analog experiments where Buttiauxella sp. MASE-IM-9, a facultative anaerobe, survived a maximum of 3 months of desiccation ( Beblo-Vranesevic et al, 2018 , 2020 ).…”

Anther‐smut fungi from more contaminated sites in Chernobyl show lower infection ability and lower viability following experimental irradiation

“…Although there is considerable variation among species, cell type, and life history stage, the lethal dose needed to kill 50% of cells (i.e., LD50) ranges from 1 to over 3,000 Gy averaging around 1,500 Gy, while the LD100 (i.e., dose required to sterilize) can exceed 15,000 Gy in some species (Sommer, 1973). Studies on bacteria have found survival rates following 500 Gy radiation exposure that varied from about 10 –1 to as low as 10 –6 (Beblo‐Vranesevic et al., 2018). Bacteria associated with bird feathers from the Chernobyl area showed similar viability reduction at 500 Gy, but these bacteria were more resistant to higher doses of radiation than was M. lychnidis‐dioicae (Ruiz‐González et al., 2016).…”