Stress-Tolerance and Taxonomy of Culturable Bacterial Communities Isolated from a Central Mojave Desert Soil Sample

Abstract

The arid Mojave Desert is one of the most significant terrestrial analogue objects for astrobiological research due to its genesis, mineralogy, and climate. However, the knowledge of culturable bacterial communities found in this extreme ecotope’s soil is yet insufficient. Therefore, our research has been aimed to fulfil this lack of knowledge and improve the understanding of functioning of edaphic bacterial communities of the Central Mojave Desert soil. We characterized aerobic heterotrophic soil bacterial communities of the central region of the Mojave Desert. A high total number of prokaryotic cells and a high proportion of culturable forms in the soil studied were observed. Prevalence of Actinobacteria, Proteobacteria, and Firmicutes was discovered. The dominance of pigmented strains in culturable communities and high proportion of thermotolerant and pH-tolerant bacteria were detected. Resistance to a number of salts, including the ones found in Martian regolith, as well as antibiotic resistance, were also estimated.

Bacterial Communities of Novaya Zemlya Archipelago Ice and Permafrost

“…It is also remarkable that representatives of Agrococcus, Arthrobacter, Bacillus, Brachybacterium, Brevibacillus, Brevibacterium, Glutamicibacter, Leucobacter, Microbacterium, Micrococcus, Planomicrobium, Pseudoarthrobacter, Pseudochrobactrum, Rhodococcus, Sphingomonas, Streptomyces genera and Leucobacter aridicollis, Microbacterium oxydans, Planomicrobium okeanokoites, Pseudomonas putida, Stenotrophomonas maltophilia species were isolated under the identical culturing conditions from non-freezing semi-arid and arid desert soils earlier [6,15] as well as from ice and permafrost samples in the current study. On the one hand, it could be caused by the same culturing conditions performed in these studies.…”

“…To assess the potential metabolic activity of the [Nz 2] sample microbial community, the multisubstrate testing (MST) was performed ( [6] and references therein). The testing was carried out with 47 substrates including sugars, alcohols, amino acids, salts of organic acids, and polymers (all substrates are listed in Reference [56]; all tests were performed in two replicates).…”

“…Peptone Yeast Glucose (PYG) medium rich in various carbon sources and nutrients (glucose: 1 g/L, peptone: 2 g/L, yeast extract: 1 g/L, tryptone: 1 g/L, agar: 20 g/L) and modified Czapek (CM) medium (glucose: 2 g/L, sucrose: 2 g/L, starch: 2 g/L, NaNO 3 : 2 g/L, KH 2 PO 4 : 1 g/L, MgSO 4 : 0.5 g/L, KCl: 0.2 g/L, agar: 20 g/L) [6] were used for bacteria culturing and isolation. These media were used to increase the proportion of culturable bacteria analysed from the samples studied.…”

“…If the procedure failed to obtain the PCR product by the first primer system, the next primer system with the same DNA matrix was used and of 27 so on until a product that can be used for further sequencing was acquired. The detailed protocol is described in Reference [6].…”

“…The objective of this study was to investigate the structure and stress tolerance of bacterial communities associated with virtually microbiologically unexplored Arctic sediments and ice collected in the northern part of Novaya Zemlya archipelago. The present study is a part of a research project that aims to reveal the structure and physiological properties of bacterial communities (especially culturable bacteria) associated with different extreme environments [6,15].…”