Bacterial Growth in Chloride and Perchlorate Brines: Halotolerances and Salt Stress Responses of Planococcus halocryophilus
| Autor: | Armando Alibrandi, Janosch Schirmack, Alessandro Airo, Annemiek C. Waajen, Jacob Heinz, Dirk Schulze-Makuch |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Extraterrestrial Environment
010504 meteorology & atmospheric sciences growth halotolerance Salt (chemistry) Mars Bacterial growth perchlorate Salt Stress 01 natural sciences Chloride Extremophiles Perchlorate chemistry.chemical_compound Chlorides ddc:570 0103 physical sciences medicine salt Planococcus halocryophilus 010303 astronomy & astrophysics Research Articles 0105 earth and related environmental sciences chemistry.chemical_classification Perchlorates Cold-Shock Response Osmolar Concentration brines 520 Astronomie und zugeordnete Wissenschaften Agricultural and Biological Sciences (miscellaneous) Cold Temperature chemistry Space and Planetary Science Planococcaceae Environmental chemistry Halotolerance ddc:520 Salts Earth (classical element) Extreme Environments medicine.drug 570 Biowissenschaften Biologie |
| Zdroj: | Astrobiology |
| DOI: | 10.14279/depositonce-8917 |
| Popis: | Extraterrestrial environments encompass physicochemical conditions and habitats that are unknown on Earth, such as perchlorate-rich brines that can be at least temporarily stable on the martian surface. To better understand the potential for life in these cold briny environments, we determined the maximum salt concentrations suitable for growth (MSCg) of six different chloride and perchlorate salts at 25°C and 4°C for the extremotolerant cold- and salt-adapted bacterial strain Planococcus halocryophilus. Growth was measured through colony-forming unit (CFU) counts, while cellular and colonial phenotypic stress responses were observed through visible light, fluorescence, and scanning electron microscopy. Our data show the following: (1) The tolerance to high salt concentrations can be increased through a stepwise inoculation toward higher concentrations. (2) Ion-specific factors are more relevant for the growth limitation of P. halocryophilus in saline solutions than single physicochemical parameters like ionic strength or water activity. (3) P. halocryophilus shows the highest microbial sodium perchlorate tolerance described so far. However, (4) MSCg values are higher for all chlorides compared to perchlorates. (5) The MSCg for calcium chloride was increased by lowering the temperature from 25°C to 4°C, while sodium- and magnesium-containing salts can be tolerated at 25°C to higher concentrations than at 4°C. (6) Depending on salt type and concentration, P. halocryophilus cells show distinct phenotypic stress responses such as novel types of colony morphology on agar plates and biofilm-like cell clustering, encrustation, and development of intercellular nanofilaments. This study, taken in context with previous work on the survival of extremophiles in Mars-like environments, suggests that high-concentrated perchlorate brines on Mars might not be habitable to any present organism on Earth, but extremophilic microorganisms might be able to evolve thriving in such environments. |
| Databáze: | OpenAIRE |
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