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The Tibetan Plateau niche provides unprecedented opportunities to find microbes that are functional and commercial significance. The present study investigated the physiological and genomic characteristics of Planococcus halotolerans Y50 that was isolated from a petroleum-contaminated soil sample from the Qinghai-Tibet Plateau, and it displayed psychrotolerant, antiradiation, and oil-degraded characteristics. Whole genome sequencing indicated that strain Y50 has a 3.52 Mb genome and 44.7% G + C content, and it possesses 3377 CDSs. The presence of a wide range of UV damage repair genes uvrX and uvsE, DNA repair genes radA and recN, superoxide dismutase, peroxiredoxin and dioxygenase genes provided the genomic basis for the adaptation of the plateau environment polluted by petroleum. Related experiments also verified that the Y50 strain could degrade n-alkanes from C 11 -C 23 , and approximately 30% of the total petroleum at 25 °C within 7 days. Meanwhile, strain Y50 could withstand 5 × 10 3 J/m 2 UVC and 10 KGy gamma ray radiation, and it had strong antioxidant and high radical scavengers for superoxide anion, hydroxyl radical and DPPH. In addition, pan-genome analysis and horizontal gene transfers revealed that strains with different niches have obtained various genes through horizontal gene transfer in the process of evolution, and the more similar their geographical locations, the more similar their members are genetically and ecologically. In conclusion, P. halotolerans Y50 possesses high potential of applications in the bioremediation of alpine hydrocarbons contaminated environment., (Copyright © 2022 Elsevier B.V. All rights reserved.)

A bacterial strain, designated Y40 T , was isolated from sandy soil sampled on the Qinghai-Tibet Plateau. A polyphasic study confirmed the affiliation of the strain with the genus Mesobacillus . Strain Y40 T was found to be an aerobic, Gram-stain-positive, motile and rod-shaped bacterium. The strain grew at 10-42 °C, pH 6-9 and with 0-2 % (w/v) NaCl. The diagnostic amino acid was meso -diaminopimeilic acid. MK7 was predominant menaquinone, and iso-C 15:0 , iso-C 17:1 ω10 c and anteiso-C 15:0 were the major fatty acids. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified lipid. The DNA G+C content was 40.6 mol%. Based on he results of 16S rRNA gene sequence analysis, strain Y40 T was phylogenetically closely related to Mesobacillus zeae JJ-247 T and Mesobacillus foraminis CV53 T , with similarities of 98.0 and 97.7 %, respectively. The average nucleotide identity (ANIb) values between strain Y40 T and Mesobacillus zeae JJ-247 T and Mesobacillus foraminis CV53 T were 69.9 and 70.0 %, respectively. Based on the morphological, physiological, and chemotaxonomic data, it is proposed that strain Y40 T (=CICC 24459 T =JCM 32794 T ) should be classified into the genus Mesobacillus as Mesobacillus harenae sp. nov.

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 genus Planococcus. Strain Y74 T was able to grow between 4 and 42°C (with an optimum temperature of 28°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 ω7c 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 and Planococcus halotolerans SCU63 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 genus Planococcus, for which the name Planococcus antioxidans sp. 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 ., (© 2020 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

A bacterial strain, designated GEM5 T , was isolated from sand soil samples from the Qinghai-Tibet Plateau. The polyphasic study confirmed the affiliation of the isolate with the genus Massilia . GEM5 T had Gram-stain-negative, non-spore-forming and rod-shaped cells and grew at 4-30 °C, pH 6-8 and with 0-2 % (w/v) NaCl. Its cell wall contained ribose. Q8 was the predominant respiratory quinone, and summed feature 3 (C 16 : 1 ω6 c /ω7 c ) and C 16 : 0 were the major components of the fatty acids. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified phospholipid, an unidentified aminolipid and four unidentified lipids. The DNA G+C content was 65.1 mol%. The phylogenetic analysis based on the 16S rRNA gene showed a stable clade being formed by GEM5 T , Massilia timonae CCUG 45783 T (97.94 %) and Massilia oculi CCUG 43427A T (97.58 %). The average nucleotide identity (ANIb) values between GEM5 T and M. timonae CCUG 45783 T , M.oculi CCUG 43427A T were 91.3 and 91.7 %, respectively. On the basis of the morphological, physiological and chemotaxonomic pattern, it was proposed that strain GEM5 T (=JCM 32744 T =CICC 24458 T ) should be classified as representing a member of the genus Massilia with the name Massilia arenae sp. nov.

The Qinghai-Tibet Plateau glaciers are an important carrier of mercury (Hg). With global warming, Hg enters into the downstream ecosystem in the melt waters, threatening human health and ecosystem security in the region. Methylmercury (MeHg), which has higher toxicity than Hg itself, is converted from inorganic Hg. However, little is known about the process of Hg methylation and, in particular, microbial Hg methylation in high altitude mountain glaciers. We combined Hg speciation measurements and metagenomic analysis of 6 sample types from the terminus of Laohugou No.12 glacier to elucidate potential microbially mediated Hg methylation. We found higher Hg concentrations in supraglacial cryoconite (SC) and dusty layer (DL) samples which contain considerable debris and dust. In addition, MeHg concentrations were highest in some of these SC and DL samples. Bacterial hgcA Hg methylation genes were present in all samples except supraglacial ice but were of highest abundance in SC and DL. This suggested that microbial Hg methylation is most likely to occur in SC and DL. There were 8 phyla of potential Hg methylation microorganisms, but 37% of the sequences could not be classified into any known genus. Most of the hgcA sequences were closely related to sequences from previously reported Hg methylating genera within the Deltaproteobacteria and Firmicutes, but the common Hg methylating Methanomicrobia were absent in glacial samples., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A novel actinobacterial strain, designated Z022 T , isolated from a soil sample collected from Dangxiong in Tibet Autonomous Region (PR China), was determined by polyphasic taxonomic approach. The organism had chemotaxonomic and morphological properties consistent with its classification in the genus Streptomyces. Strain Z022 T showed high similarity value to Streptomyces lucensis NBRC 13056 T (98.87 %) and S. achromogenes subsp . achromogenes NBRC 12735 T (98.68 %) based on the 16S rRNA gene phylogenetic tree. The genomic DNA G+C content of strain Z022 T based on the genome sequence was 72.16 mol%. DNA-DNA relatedness values between strain Z022 T and strain Streptomyces lucensis NBRC 13056 T was 23.7±1.3 % and significantly lower than 70 %. Chemotaxonomic data revealed that strain Z022 T possessed MK-9(H 8 ) and MK-9(H 6 ) as the predominant menaquinone, ll-diaminopimelic acid as the diagnostic diamino acid, and galactose, glucose, xylose and ribose as whole cell sugars. Diphosphatidylglycerol (DPG) and phosphatidylethanolamine (PE) were the predominant polar lipids; anteiso-C 15 : 0 , iso-C 16 : 0 , and anteiso-C 17 : 0 were the major fatty acids. On the basis of these genotypic and phenotypic data, it is proposed that isolate Z022 T (=JCM 31053 T =CGMCC 4.7273 T ) should be classified in the genus Streptomyces as Streptomyces dangxiongensis sp. nov.

This study investigates the biodegradation of crude oil by a mixed culture of bacteria isolated from the Qinghai-Tibet plateau using gas chromatography-mass spectrometer (GC-MS) and the gravimetric method. The results showed that a mixed culture has a stronger ability to degrade hydrocarbon than pure cultures. Once both Nocardia soli Y48 and Rhodococcus erythropolis YF28-1 (8) were present in a culture, the culture demonstrated the highest crude oil removal efficiency of almost 100% after 10 days of incubation at 20 °C. Moreover, further analysis of the degradation mechanisms used by the above strains, which revealed utilization of different n-alkane substrates, indicated the diversity of evolution and variations in different strains, as well as the importance of multiple metabolic mechanisms for alkane degradation. Therefore, it is concluded that a mixed culture of Y48 and YF28-1 (8) strains can provide a more effective method for bioremediation of hydrocarbon-contaminated soil in permafrost regions.