Thiomicrorhabdus streamers and sulfur cycling in perennial hypersaline cold springs in the Canadian high Arctic

Abstract

The Gypsum Hill (GH) springs on Axel Heiberg Island in the Canadian high Arctic are host to chemolithoautotrophic, sulfur-oxidizing streamers that flourish in the high Arctic winter in water temperatures from −1.3 to 7 C with~8% salinity in a high Arctic winter environment with air temperatures commonly less than −40 C and an average annual air temperature of −15 C. Metagenome sequencing and binning of streamer samples produced a 96% complete Thiomicrorhabdus sp. metagenome-assembled genome representing a possible new species or subspecies. This is the most cold-and salt-extreme source environment for a Thiomicrorhabdus genome yet described. Metaproteomic and metatranscriptomic analysis attributed nearly all gene expression in the streamers to the Thiomicrorhabdus sp. and suggested that it is active in CO 2 fixation and oxidation of sulfide to elemental sulfur. In situ geochemical and isotopic analyses of the fractionation of multiple sulfur isotopes determined the biogeochemical transformation of sulfur from its source in Carboniferous evaporites to biotic processes occurring in the sediment and streamers. These complementary molecular tools provided a functional link between the geochemical substrates and the collective traits and activity that define the microbial community's interactions within a unique polar saline habitat where Thiomicrorhabdus-dominated streamers form and flourish.

Hot in Cold: Microbial Life in the Hottest Springs in Permafrost

“…Hydrothermal springs located in permafrost are not a unique phenomenon, though they are rather fascinating. The most northern among currently known terrestrial geothermal springs are located in Canada [7,8] and Norway (Svalbard Island) [9] permafrost areas at a latitude of almost 80 • N. Water temperatures there do not exceed 7 and 26 • C, respectively. Springs in Greenland (Denmark) are heated to 55-62 • C [10].…”

MinION sequencing from sea ice cryoconites leads to de novo genome reconstruction from metagenomes

“…Proper protein folding is maintained in Hybrid_5 by peptidyl-prolyl cis–trans isomerase and tig 8 . Membrane fluidity is negatively impacted at cold temperatures, and Hybrid_5 appears to compensate for this effect with several membrane, pepetidoglycan, and polysaccharide capsule alteration and production genes including peptidoglycan synthesis genes murABCDEF, fatty acid elongation genes fabBFGH , and exopolysaccharide biosynthesis gene epsC 68 , 69 , 73 , 74 .…”

The Methods of Digging for “Gold” within the Salt: Characterization of Halophilic Prokaryotes and Identification of Their Valuable Biological Products Using Sequencing and Genome Mining Tools

“…Thanks to their use, it is possible to identify active metabolic pathways in the environmental niche, which gives a unique insight into its characteristics. The best results are achieved by combining metagenomics with metatranscriptomics analysis, where the former one identifies genes in the studied microbiome and allows the creation of MAGs (metagenome-assembled genomes), while the latter one allows assessing the expression level of the detected genes [115,116]. Despite the great potential of obtaining significantly valuable data in this way, still relatively unpopular experiments due to the great difficulties in receiving the appropriate quality material for research from saline environments due to the low available biomass and a high diversity of the samples are observed [117].…”

“…Recently, there have been attempts to use proteomics to directly analyse environmental samples, but this is difficult and still rarely applied. The main reason for the difficulties in using proteomics is the low biomass of proteins in the analyzed samples [115]. In the following part of this article, we will focus on characterising the methods based on nucleic acid sequencing and their role in understanding the biodiversity and biotechnological potential of microorganisms living in saline environments.…”