A Novel Cold-adapted Methylovulum species, with a High C16:1ω5c Content, Isolated from an Arctic Thermal Spring in Spitsbergen.
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SUBMITTER: Islam T
PROVIDER: S-EPMC7511782 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundGypsum Hill Spring, located in Nunavut in the Canadian High Arctic, is a rare example of a cold saline spring arising through thick permafrost. It perennially discharges cold (~ 7 °C), hypersaline (7-8% salinity), anoxic (~ 0.04 ppm O2), and highly reducing (~ - 430 mV) brines rich in sulfate (2.2 g.L-1) and sulfide (9.5 ppm), making Gypsum Hill an analog to putative sulfate-rich briny habitats on extraterrestrial bodies such as Mars.ResultsGenome-resolved metagenomics and metatranscriptomics were utilized to describe an active microbial community containing novel metagenome-assembled genomes and dominated by sulfur-cycling Desulfobacterota and Gammaproteobacteria. Sulfate reduction was dominated by hydrogen-oxidizing chemolithoautotrophic Desulfovibrionaceae sp. and was identified in phyla not typically associated with sulfate reduction in novel lineages of Spirochaetota and Bacteroidota. Highly abundant and active sulfur-reducing Desulfuromusa sp. highly transcribed non-coding RNAs associated with transcriptional regulation, showing potential evidence of putative metabolic flexibility in response to substrate availability. Despite low oxygen availability, sulfide oxidation was primarily attributed to aerobic chemolithoautotrophic Halothiobacillaceae. Low abundance and transcription of photoautotrophs indicated sulfur-based chemolithoautotrophy drives primary productivity even during periods of constant illumination.ConclusionsWe identified a rare surficial chemolithoautotrophic, sulfur-cycling microbial community active in a unique anoxic, cold, hypersaline Arctic spring. We detected Mars-relevant metabolisms including hydrogenotrophic sulfate reduction, sulfur reduction, and sulfide oxidation, which indicate the potential for microbial life in analogous S-rich brines on past and present Mars. Video Abstract.
| S-EPMC10494364 | biostudies-literature
Project description:In many studied plants, typical responses to cold treatment include up-regulating the hydrophilic COR/LEA genes and down-regulating photosynthesis-related genes, carbohydrate metabolism, GDSL-motif lipase, hormone metabolism and oxidative regulation genes. However, next to nothing is known about gene expression in arctic plants, which are actually adapted to a harsh, cold environment. The molecular mechanisms behind the many specific adaptations of arctic plants, such as slow growth, well-developed root systems and short stature, are not well understood. In this study, we examine whole plantlet transcriptome differences between two arctic and two temperate Oxytropis (Fabaceae) species, grown under their respective controlled environmental conditions. Gene expression differences are analyzed using cDNA library subtraction followed by expressed sequence tags sequencing and annotation. Sequences from a total of nearly 2,000 clones cluster into 121 and 368 unique genes from the arctic and from the temperate plants, respectively. The predominant biological process for genes from the arctic-enriched library is "response to stimulus". A concurrent overexpression of pathogenesis-related class 10 proteins (PR-10), plant defensin and cold dehydrin genes is a novel feature for species adapted to stressful growth environment. The temperate-enriched genes are involved in photosynthesis, translation and nucleosome assembly. Interestingly, both arctic and temperate-enriched libraries also contain genes involved in ribosome biogenesis and assembly, however of different types. Real-time reverse transcription PCR of cold dehydrin and two PR-10 genes, as well as the light harvesting complex b1 genes demonstrates that the gene expression is dependent on species and growth conditions.
| S-EPMC3156302 | biostudies-literature
Project description:The Arctic is warming at approximately twice the global rate, with well-documented indirect effects on wildlife. However, few studies have examined the direct effects of warming temperatures on Arctic wildlife, leaving the importance of heat stress unclear. Here, we assessed the direct effects of increasing air temperatures on the physiology of thick-billed murres (Uria lomvia), an Arctic seabird with reported mortalities due to heat stress while nesting on sun-exposed cliffs. We used flow-through respirometry to measure the response of body temperature, resting metabolic rate, evaporative water loss and evaporative cooling efficiency (the ratio of evaporative heat loss to metabolic heat production) in murres while experimentally increasing air temperature. Murres had limited heat tolerance, exhibiting: (1) a low maximum body temperature (43.3°C); (2) a moderate increase in resting metabolic rate relative that within their thermoneutral zone (1.57 times); (3) a small increase in evaporative water loss rate relative that within their thermoneutral zone (1.26 times); and (4) a low maximum evaporative cooling efficiency (0.33). Moreover, evaporative cooling efficiency decreased with increasing air temperature, suggesting murres were producing heat at a faster rate than they were dissipating it. Larger murres also had a higher rate of increase in resting metabolic rate and a lower rate of increase in evaporative water loss than smaller murres; therefore, evaporative cooling efficiency declined with increasing body mass. As a cold-adapted bird, murres' limited heat tolerance likely explains their mortality on warm days. Direct effects of overheating on Arctic wildlife may be an important but under-reported impact of climate change.
| S-EPMC8278010 | biostudies-literature
Project description:The oxidative challenge represents an important factor affecting the adaptive strategies in Antarctic fish, but their impact on the protein degradation machinery still remains unclear. The previous analysis of the first 26S proteasome from the Antarctic red-blooded fish Trematomus bernacchii, evidenced improved antioxidant functions necessary to counteract the environmental pro-oxidant conditions. The purpose of this work was to carry out a study on 26S proteasomes from the temperate red-blooded Dicenthrarcus labrax and the icefish Chionodraco hamatus in comparison with the isoform already described from T. bernacchii, to better elucidate the cold-adapted physiological functions of this complex. Therefore, the 26S isoforms were isolated and the complementary DNAs (cDNAs) codifying the catalytic subunits were cloned. The biochemical characterization of Antarctic 26S proteasomes revealed their significantly higher structural stability and resistance to H?O? with respect to that of the temperate counterpart, as also suggested by a comparative modeling analysis of the catalytic subunits. Moreover, in contrast to that observed in T. bernacchii, the 26S systems from C. hamatus and D. labrax were incapable to hydrolyze oxidized proteins in a ubiquitin-independent manner. Therefore, the 'uncommon' properties displayed by the Antarctic 26S proteasomes can mirror the impact exercised by evolutionary pressure in response to richly oxygenated environments.
| S-EPMC5577997 | biostudies-literature
Project description:Organisation EGAO00000000257
| EGAO00000000257 | EGA
Project description:Species expand towards higher latitudes in response to climate warming, but the pace of this expansion is related to the physiological capacity to resist cold stress. However, few studies exist that have quantified the level of inter-population local adaptation in marine species freeze tolerance, especially in the Arctic. We investigated the importance of cold adaptation and thermal window width towards high latitudes from the temperate to the Arctic region. We measured upper and lower lethal air temperatures (i.e. LT and LT50) in temperate and Arctic populations of blue mussels (Mytilus edulis), and analysed weather data and membrane fatty acid compositions, following emersion simulations. Both populations had similar upper LT (~38 °C), but Arctic mussels survived 4°C colder air temperatures than temperate mussels (-13 vs. -9°C, respectively), corresponding to an 8% increase in their thermal window. There were strong latitudinal relationships between thermal window width and local air temperatures, indicating Arctic mussels are highly adapted to the Arctic environment where the seasonal temperature span exceeds 60°C. Local adaptation and local habitat heterogeneity thus allow leading-edge M. edulis to inhabit high Arctic intertidal zones. This intraspecific pattern provides insight into the importance of accounting for cold adaptation in climate change, conservation and biogeographic studies.
| S-EPMC6933310 | biostudies-literature
Project description:The marine genus Pseudoalteromonas is known for its versatile biotechnological potential with respect to the production of antimicrobials and enzymes of industrial interest. We have sequenced the genomes of three Pseudoalteromonas sp. strains isolated from different deep sea sponges on the Illumina MiSeq platform. The isolates have been screened for various industrially important enzymes and comparative genomics has been applied to investigate potential relationships between the isolates and their host organisms, while comparing them to free-living Pseudoalteromonas spp. from shallow and deep sea environments. The genomes of the sponge associated Pseudoalteromonas strains contained much lower levels of potential eukaryotic-like proteins which are known to be enriched in symbiotic sponge associated microorganisms, than might be expected for true sponge symbionts. While all the Pseudoalteromonas shared a large distinct subset of genes, nonetheless the number of unique and accessory genes is quite large and defines the pan-genome as open. Enzymatic screens indicate that a vast array of enzyme activities is expressed by the isolates, including ?-galactosidase, ?-glucosidase, and protease activities. A ?-glucosidase gene from one of the Pseudoalteromonas isolates, strain EB27 was heterologously expressed in Escherichia coli and, following biochemical characterization, the recombinant enzyme was found to be cold-adapted, thermolabile, halotolerant, and alkaline active.
| S-EPMC5484134 | biostudies-literature
Project description:A novel Gram-stain-positive, aerobic bacterial strain, designated AK-R2A1-2 T, was isolated from the surface-sterilized needle leaves of an Abies koreana tree. Strain AK-R2A1-2 T had 97.3% and 96.7% 16S rRNA gene sequence similarities with Subtercola boreus K300T and Subtercola lobariae 9583bT, respectively, but formed a distinct phyletic lineage from these two strains. Growth of strain AK-R2A1-2 T was observed at 4-25 °C at pH 5.0-8.0. Strain AK-R2A1-2 T contained menaquinone 9 (MK-9) and menaquinone 10 (MK-10) as the predominant respiratory quinones. The major cellular fatty acids were anteiso-C15:0 and summed feature 8 (C18:1ω7c or/and C18:1ω6c), and the polar lipids included diphosphatidylglycerol (DPG) and three unknown aminolipids, AKL2, AKL3, and AKL4. The complete genome of strain AK-R2A1-2 T was sequenced to understand the genetic basis of its survival at low temperatures. Multiple copies of cold-associated genes involved in cold-active chaperon, stress response, and DNA repair supported survival of the strain at low temperatures. Strain AK-R2A1-2 T was also able to significantly improve rice seedling growth under low temperatures. Thus, this strain represents a novel species of the genus Subtercola, and the proposed name is Subtercola endophyticus sp. nov. The type strain is AK-R2A1-2 T (= KCTC 49721 T = GDMCC 1.2921 T).
| S-EPMC9287328 | biostudies-literature
Project description:Arctic charr is an especially attractive aquaculture species given that it features the desirable tissue traits of other salmonids, but can be bred and grown at inland freshwater tank farms year round. It is therefore of interest to develop upper temperature tolerant (UTT) strains of Arctic charr to increase the robustness of the species in the face of climate change, as well as to enable production in more southern regions. We conducted an acute temperature trial to identify temperature tolerant and intolerant Arctic charr individuals. Specifically, approximately 200 fish were transferred to an experimental tank (diameter: 1.86 m, depth 50 cm) and left to acclimate for 48 h at ambient temperature. After acclimation, 10 fish were removed to act as a control group, then water that had been diverted through a heat exchanger was added to the flow-through system to increase the water temperature in the tank by 6°C/h until it reached 22°C, then 0.5°C every 30 min until the water reached 25°C, the observed lethal temperature for these fish. When the water temperature reached 25°C, the temperature was held constant and the fish were closely monitored for signs of stress. The first and last 10 individuals to show loss of balance were quickly removed from the tank for sampling, thus representing the 5% least and most temperature tolerant fish, respectively. A reference design microarray study was then performed with the cGRASP 32K microarray using six samples from each group (Intolerant, Tolerant, Control) to identify genes differentially expressed between groups. The results of this study will feed into an ongoing Arctic charr marker-assisted selection based broodstock development program, and may contribute to population-based conservation initiatives for salmonids in general.
2011-06-01 | GSE26306 | GEO
Project description:The capacity of ectotherms to cope with rising temperatures associated with climate change is a significant conservation concern as the rate of warming is likely too rapid to allow for adaptative responses in many populations. Transgenerational plasticity (TGP), if present, could potentially buffer some of the negative impacts of warming on future generations. We examined TGP in lake trout to assess their inter-generational potential to cope with anticipated warming. We acclimated adult lake trout to cold (10°C) or warm (17°C) temperatures for several months, then bred them to produce offspring from parents within a temperature treatment (cold-acclimated and warm-acclimated parents) and between temperature treatments (i.e. reciprocal crosses). At the fry stage, offspring were also acclimated to cold (11°C) or warm (15°C) temperatures. Thermal performance was assessed by measuring their critical thermal maximum (CTM) and the change in metabolic rate during an acute temperature challenge. From this dataset, we also determined their resting and peak (highest achieved, thermally induced) metabolic rates. There was little variation in offspring CTM or peak metabolic rate, although cold-acclimated offspring from warm-acclimated parents exhibited elevated resting metabolic rates without a corresponding increase in mass or condition factor, suggesting that transgenerational effects can be detrimental when parent and offspring environments mismatch. These results suggest that the limited TGP in thermal performance of lake trout is unlikely to significantly influence population responses to projected increases in environmental temperatures.
| S-EPMC8071478 | biostudies-literature