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Deinococcus species, noted for their exceptional resistance to DNA-damaging environmental stresses, have piqued scientists' interest for decades. This study dives into the complex mechanisms underpinning radiation resistance in the Deinococcus genus. We have examined the genomes of 82 Deinococcus species and classified radiation-resistance proteins manually into five unique curated categories: DNA repair, oxidative stress defense, Ddr and Ppr proteins, regulatory proteins, and miscellaneous resistance components. This classification reveals important information about the various molecular mechanisms used by these extremophiles which have been less explored so far. We also investigated the presence or lack of these proteins in the context of phylogenetic relationships, core, and pan-genomes, which offered light on the evolutionary dynamics of radiation resistance. This comprehensive study provides a deeper understanding of the genetic underpinnings of radiation resistance in the Deinococcus genus, with potential implications for understanding similar mechanisms in other organisms using an interactomics approach. Finally, this study reveals the complexities of radiation resistance mechanisms, providing a comprehensive understanding of the genetic components that allow Deinococcus species to flourish under harsh environments. The findings add to our understanding of the larger spectrum of stress adaption techniques in bacteria and may have applications in sectors ranging from biotechnology to environmental research.

期刊论文 2024-10-01 DOI: 10.1016/j.compbiolchem.2024.108161 ISSN: 1476-9271

为研究埋地二氧化碳管道周围土壤温度场的分布规律,基于齐鲁石化-胜利油田百万吨级CCUS示范项目二氧化碳输送管道,建立管道周围土壤温度场数值模型,采用Fluent软件对二氧化碳三种输送相态(低压液相、高压液相、超临界)下的典型工况土壤温度场进行计算。在低压液相输送的基础上分析管道周围土壤冻结范围的季节变化规律及不同埋深、不同运行温度对管道周围土壤冻结范围的影响,研究结果表明:随着埋深增大,管道周围多年冻土范围增大,季节性冻土范围受影响较小;而随着起点温度的升高,管道周围多年冻土和季节性冻土范围都减小,当温度升高至0℃时将不再形成冻土。在高压液相输送和超临界输送的基础上,以小麦为例分析管道运行温度变化对地表植被的影响,研究结果表明:为使土壤温度能满足沿线农作物生长需求,二氧化碳高压液相输送时,其管输介质温度不宜低于5℃,超临界输送时不宜高于50℃。

期刊论文 2024-08-21

为研究埋地二氧化碳管道周围土壤温度场的分布规律,基于齐鲁石化-胜利油田百万吨级CCUS示范项目二氧化碳输送管道,建立管道周围土壤温度场数值模型,采用Fluent软件对二氧化碳三种输送相态(低压液相、高压液相、超临界)下的典型工况土壤温度场进行计算。在低压液相输送的基础上分析管道周围土壤冻结范围的季节变化规律及不同埋深、不同运行温度对管道周围土壤冻结范围的影响,研究结果表明:随着埋深增大,管道周围多年冻土范围增大,季节性冻土范围受影响较小;而随着起点温度的升高,管道周围多年冻土和季节性冻土范围都减小,当温度升高至0℃时将不再形成冻土。在高压液相输送和超临界输送的基础上,以小麦为例分析管道运行温度变化对地表植被的影响,研究结果表明:为使土壤温度能满足沿线农作物生长需求,二氧化碳高压液相输送时,其管输介质温度不宜低于5℃,超临界输送时不宜高于50℃。

期刊论文 2024-08-21

为研究埋地二氧化碳管道周围土壤温度场的分布规律,基于齐鲁石化-胜利油田百万吨级CCUS示范项目二氧化碳输送管道,建立管道周围土壤温度场数值模型,采用Fluent软件对二氧化碳三种输送相态(低压液相、高压液相、超临界)下的典型工况土壤温度场进行计算。在低压液相输送的基础上分析管道周围土壤冻结范围的季节变化规律及不同埋深、不同运行温度对管道周围土壤冻结范围的影响,研究结果表明:随着埋深增大,管道周围多年冻土范围增大,季节性冻土范围受影响较小;而随着起点温度的升高,管道周围多年冻土和季节性冻土范围都减小,当温度升高至0℃时将不再形成冻土。在高压液相输送和超临界输送的基础上,以小麦为例分析管道运行温度变化对地表植被的影响,研究结果表明:为使土壤温度能满足沿线农作物生长需求,二氧化碳高压液相输送时,其管输介质温度不宜低于5℃,超临界输送时不宜高于50℃。

期刊论文 2024-08-21

Background The bacterial mechanisms responsible for hydrogen peroxide (H2O2) scavenging have been well-reported, yet little is known about how bacteria isolated from cold-environments respond to H2O2 stress. Therefore, we investigated the transcriptional profiling of the Planomicrobium strain AX6 strain isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China, in response to H2O2 stress aiming to uncover the molecular mechanisms associated with H2O2 scavenging potential. Methods We investigated the H2O2-scavenging potential of the bacterial Planomicrobium strain AX6 isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China. Furthermore, we used high-throughput RNA-sequencing to unravel the molecular aspects associated with the H2O2 scavenging potential of the Planomicrobium strain AX6 isolate. Results In total, 3,427 differentially expressed genes (DEGs) were identified in Planomicrobium strain AX6 isolate in response to 4 h of H2O2 (1.5 mM) exposure. Besides, Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology analyses revealed the down- and/or up-regulated pathways following H2O2 treatment. Our study not only identified the H2O2 scavenging capability of the strain nevertheless also a range of mechanisms to cope with the toxic effect of H2O2 through genes involved in oxidative stress response. Compared to control, several genes coding for antioxidant proteins, including glutathione peroxidase (GSH-Px), Coproporphyrinogen III oxidase, and superoxide dismutase (SOD), were relatively up-regulated in Planomicrobium strain AX6, when exposed to H2O2. Conclusions Overall, the results suggest that the up-regulated genes responsible for antioxidant defense pathways serve as essential regulatory mechanisms for removing H2O2 in Planomicrobium strain AX6. The DEGs identified here could provide a competitive advantage for the existence of Planomicrobium strain AX6 in H2O2-polluted environments.

期刊论文 2024-07-01 DOI: http://dx.doi.org/10.1186/s12866-022-02677-w ISSN: 1471-2180

Evidence of stable liquid water oceans beneath the ice crust of moons within the Solar System is of great interest for astrobiology. In particular, subglacial oceans may present hydrothermal processes in their abysses, similarly to terrestrial hydrothermal vents. Therefore, terrestrial extremophilic deep life can be considered a model for putative icy moon extraterrestrial life. However, the comparison between putative extraterrestrial abysses and their terrestrial counterparts suffers from a potentially determinant difference. Indeed, some icy moons oceans may be so deep that the hydrostatic pressure would exceed the maximal pressure at which hydrothermal vent organisms have been isolated. While terrestrial microorganisms that are able to survive in such conditions are known, the effect of high pressure on fundamental biochemical processes is still unclear. In this study, the effects of high hydrostatic pressure on DNA synthesis catalyzed by DNA polymerases are investigated for the first time. The effect on both strand displacement and primer extension activities is measured, and pressure tolerance is compared between enzymes of various thermophilic organisms isolated at different depths.

期刊论文 2024-02-01 DOI: 10.1089/ast.2021.0201 ISSN: 1531-1074

A bacterial strain, designated S9-5(T), was isolated from moraine samples collected from the north slope of Mount Everest at an altitude of 5500 m above sea level. A polyphasic study confirmed the affiliation of the strain with the genus Sphingomonas. Strain S9-5(T) was an aerobic, Gram-stain-negative, non-spore-forming, non-motile and rod-shaped bacterium that could grow at 10-40 degrees C, pH 5-8 and with 0-9% (w/v) NaCl. Q-10 was its predominant respiratory menaquinone. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminophospholipid and eight unidentified lipids comprised the polar lipids of strain S9-5(T). Its major fatty acids were summed feature 8 (C-18:1 omega 7c and/or C-18:1 omega 6c) and C-16:0. The G+C content was 65.75mol%. Phylogenetic analysis based on 16S rRNA sequences showed that strain S9-5(T) was phylogenetically closely related to Sphingomonas panaciterrae DCY91(T) (98.17%), Sphingomonas olei K-1-16(T) (98.11%) and Sphingomonas mucosissima DSM 17494(T) (97.39%). The average nucleotide identity values among strain S9-5(T) and Sphingomonas panaciterrae DCY91(T), Sphingomonas olei K-1-16(T) and Sphingomonas mucosissima DSM 17494(T) were 78.82, 78.87 and 78.29%, respectively. Based on the morphological, physiological and chemotaxonomic data, strain S9-5(T) (=JCM 34750(T)=GDMCC 1.2714(T)) should represent a novel species of the genus Sphingomonas, for which we propose the name Sphingomonas radio-durans sp. nov.

期刊论文 2020-08-01 DOI: http://dx.doi.org/10.1099/ijsem.0.005312 ISSN: 1466-5026

Strain Y74(T)was an isolate from the sandy soil in the town of Huatugou, Qinghai-Tibet Plateau, China. An analysis of this strain's phenotypic, chemotaxonomic, and genomic characteristics established the relationship of the isolate with the genusPlanococcus. Strain Y74(T)was able to grow between 4 and 42 degrees C (with an optimum temperature of 28 degrees C) at pH values of 6-8.5 and in 0%-7% (w/v) NaCl. The dominant quinones were MK-8 and MK-7. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and an unknown phospholipid. The majority of the fatty acid content was anteiso-C-15:0(28.8%) followed by C-16:1 omega 7c alcohol (20.9%) and iso-C-14:0(13.4%). The 16S rRNA gene sequence similarity analysis demonstrated a stable branch formed by strain Y74(T)andPlanococcus halotoleransSCU63(T)(99.66%). The digital DNA-DNA hybridization between these two strains was 57.2%. The G + C content in the DNA of Y74(T)was 44.5 mol%. In addition, the morphological, physiological, and chemotaxonomic pattern clearly differentiated the isolates from their known relatives. In conclusion, the strain Y74(T)(=JCM 32826(T) = CICC24461(T)) represents a novel member of the genusPlanococcus,for which the namePlanococcus antioxidanssp. nov. is proposed. Strain Y74(T)was found to have potent antioxidant activity via its hydrogen peroxide tolerance and its 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity. The DPPH radical-scavenging activity was determined to be 40.2 +/- 0.7%. The genomic analysis indicated that six peroxidases genes, one superoxide dismutase gene, and one dprA (DNA-protecting protein) are present in the genome of Y74(T).

期刊论文 2020-06-01 DOI: http://dx.doi.org/10.1002/mbo3.1028 ISSN: 2045-8827
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