Microbial community of the deep‐sea brine Lake Kryos seawater–brine interface is active below the chaotropicity limit of life as revealed by recovery of mRNA

Abstract

Microbial community of the deep-sea brine Lake Kryos seawater-brine interface is active below the chaotropicity limit of life as revealed by recovery of mRNA Yakimov, M. M., La Cono, V., Spada, G. L., Bortoluzzi, G., Messina, E., Smedile, F., ... Giuliano, L. (2015). Microbial community of the deep-sea brine Lake Kryos seawater-brine interface is active below the chaotropicity limit of life as revealed by recovery of mRNA. Environmental Microbiology, 17 (2) This is the accepted version of the following article: Microbial community of the deep-sea brine Lake Kryos seawater-brine interface is active below the chaotropicity limit of life as revealed by recovery of mRNA, Michail M. Yakimov, Violetta La Cono, Gina La Spada, Giovanni Bortoluzzi, Enzo Messina, Francesco Smedile, Erika Arcadi, Mireno Borghini, Manuel Ferrer, Phillippe Schmitt-Kopplin, Norbert Hertkorn, Jonathan A. Cray, John E. Hallsworth, Peter N. Golyshin andLaura Giuliano, which has been published in final form at ttp://onlinelibrary.wiley.com/doi/10.1111/1462-2920.12587/abstract. General rightsCopyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights.Take down policy The Research Portal is Queen's institutional repository that provides access to Queen's research output. Every effort has been made to ensure that content in the Research Portal does not infringe any person's rights, or applicable UK laws. If you discover content in the Research Portal that you believe breaches copyright or violates any law, please contact openaccess@qub.ac.uk. 25This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/1462-2920.12587 Accepted ArticleThis article is protected by copyright. All rights reserved. the microbiology of the seawater-Kryos brine interface and managed to recover mRNA from the 10 2.27-3.03 M MgCl 2 layer (equivalent to 0.747-0.631 water-activity) thereby expanding the established 11 chaotropicity window-for-life. The primary bacterial taxa present there were KB1 candidate division 12 and DHAL-specific group of organisms, distantly related to Desulfohalobium. Two euryarchaeal 13 candidate divisions MSBL1 and HC1, detected in minority in the overlaying layers, accounted for 14 more than 85% of the rRNA-containing archaeal clones analyzed in 2.27-3.03 M MgCl 2 layer. These 15 findings shed light on the plausibility of life in highly chaotropic environments, geochemical 16 windows for microbial extremophiles, and have implications for habitability elsewhere in the Solar 17 System.

Reduction of the Temperature Sensitivity of Halomonas hydrothermalis by Iron Starvation Combined with Microaerobic Conditions

“…An increasing body of evidence suggests that it is frequently the net effect of diverse stress parameters that defines the boundary space for life (8,(13)(14)(15)(16)(17)(18). The sea ice bacterium Shewanella gelidimarina, for example, has been shown to exhibit an increased temperature range for cell division when cultured at high (NaCl) salinity, with increases in membrane lipid packing and fatty acid content conferring tolerance of both conditions (13).…”

“…Despite our knowledge of the physicochemical boundaries for microbial cell division having been greatly advanced over the past three decades, we are only beginning to understand how interactions between different stressors define biological permissiveness for natural ecosystems (8,(13)(14)(15)(16)(17)(18). In particular, while several studies have identified minimal and maximal limits for microbial life in response to the surrounding environment (1,5,(19)(20)(21), there is a paucity of information on how rates of cell division are impacted by multiple stress parameters within extreme habitats.…”

Modulating Nucleation by Kosmotropes and Chaotropes: Testing the Waters

“…high cytosolic accumulation of these additives [86]. In this regard, the interactions between macromolecules and ions or ion-clusters are relevant toward defining the geochemical boundary conditions for life and predicting planetary habitability [69,87]. Such investigations indicate the non-additive nature of net chaotropic and kosmotrophic effects of solution mixtures of diverse salts and organic molecules.…”

“…Trehalose, sorbitol, ectoine, mannitol, and betaine induce increases in the pre-nucleation slope in comparison to the relative reference experiments at both pH values. At pH 9.0, this corresponds to percentage increases of about 87,44,29,26, and 20%, respectively. At higher pH (9.75), these effects are more pronounced, leading to corresponding increases of about 41,56,66,109, and 39% in the pre-nucleation slope.…”

A Halophilic Bacterium Inhabiting the Warm, CaCl 2 -Rich Brine of the Perennially Ice-Covered Lake Vanda, McMurdo Dry Valleys, Antarctica

“…The Discovery brine, the most extreme in this regard, contains about 16 times the amount of MgCl 2 of the Lake Vanda brine. However, the deep Mediterranean brines are nearly devoid of CaCl 2 , and most have high levels (3 to 4 M) of NaCl; hence, the chaotropic effects of MgCl 2 are offset somewhat by the kosmotropic effects of NaCl (47,50). Notably, however, the Discovery brine is an exception in this regard, as it contains low levels of NaCl; in terms of chaotropicity and water potential, the characteristics of this highly unusual brine are probably at or very near the limits of those that can support life (45)(46)(47)(48)(49)(50).…”