ABSTRACT
Two Gram-stain-negative, aerobic, rod-shaped, non-endospore-forming and motile bacterial strains, designated IT1137T and S025T, were isolated from an intertidal sediment sample collected from the Fildes Peninsula (King George Island, Maritime Antarctica) and a soil sample under red snow in the Ny-Ålesund region (Svalbard, High Arctic), respectively. The 16S rRNA gene sequence similarity values grouped them in the genus Pseudomonas. The two strains were characterized phenotypically using API 20E, API 20NE, API ZYM and Biolog GENIII tests and chemotaxonomically by their fatty acid contents, polar lipids and respiratory quinones. Multilocus sequence analysis (concatenated 16S rRNA, gyrB, rpoB and rpoD sequences), together with genome comparisons by average nucleotide identity and digital DNA-DNA hybridization, were performed. The results showed that the similarity values of the two isolates with the type strains of related Pseudomonas species were below the recognized thresholds for species definition. Based on polyphasic taxonomy analysis, it can be concluded that strains IT1137T and S025T represent two novel species of the genus Pseudomonas, for which the names Pseudomonas paeninsulae sp. nov. (type strain IT1137T=PMCC 100533T=CCTCC AB 2023226T=JCM 36637T) and Pseudomonas svalbardensis sp. nov. (type strain S025T=PMCC 200367T= CCTCC AB 2023225T=JCM 36638T) are proposed.
Subject(s)
Bacterial Typing Techniques , DNA, Bacterial , Fatty Acids , Geologic Sediments , Multilocus Sequence Typing , Nucleic Acid Hybridization , Phylogeny , Pseudomonas , RNA, Ribosomal, 16S , Sequence Analysis, DNA , Soil Microbiology , RNA, Ribosomal, 16S/genetics , Pseudomonas/genetics , Pseudomonas/classification , Pseudomonas/isolation & purification , Geologic Sediments/microbiology , DNA, Bacterial/genetics , Arctic Regions , Antarctic Regions , Fatty Acids/analysis , Svalbard , Base Composition , Quinones/analysisABSTRACT
To understand carbon sequestration capacity of grasslands, the changes of CO2 flux in Xilinhot grasslands and the influence of environmental factors were analyzed by using the eddy data of Xilinhot National Climate Observatory in 2018-2021, and the distribution of flux source areas was analyzed. The results showed that the southwest wind prevailed in the study area throughout the year, the source area in the growing season was larger than that in the non-growing season, and the source area under stable atmospheric conditions was larger than that under unstable conditions. The maximum length of source region with a contribution rate of 90% was close to 400 m, which was consistent with the length estimated by the classical law. The net ecosystem exchange (NEE) of Xilinhot grasslands had obvious diurnal and seasonal dynamics, which was manifested as a carbon sink in the daytime and a carbon source at night during the growing season and weak carbon source in the non-growing season. From 2018 to 2021, the annual total NEE were -15.59, -46.28, -41.94, and -78.14 g C·m-2·a-1, respectively, with an average value of -45.49 g C·m-2·a-1, indicating that Xilinhot grassland had strong carbon sequestration capacity. Vapor pressure deficit and photosynthetically active radiation helped grasslands absorb atmospheric CO2. At night, when temperature was above 0 â, the increases in air and soil temperature promoted vegetation respiration to release CO2.
Subject(s)
Carbon Dioxide , Ecosystem , Grassland , China , CarbonABSTRACT
BACKGROUND: Biological denitrification has been commonly adopted for the removal of nitrogen from sewage effluents. However, due to the low temperature during winter, microorganisms in the wastewater biological treatment unit usually encounter problems such as slow cell growth and low enzymatic efficiency. Hence, the isolation and screening of cold-tolerant aerobic denitrifying bacteria (ADB) have recently drawn attention. In our previous study, two Pseudomonas strains PMCC200344 and PMCC200367 isolated from Arctic soil demonstrated strong denitrification ability at low temperatures. The two Arctic strains show potential for biological nitrogen removal from sewage in cold environments. However, the genome sequences of these two organisms have not been reported thus far. RESULTS: Here, the basic characteristics and genetic diversity of strains PMCC200344 and PMCC200367 were described, together with the complete genomes and comparative genomic results. The genome of Pseudomonas sp. PMCC200344 was composed of a circular chromosome of 6,478,166 bp with a G + C content of 58.60% and contained a total of 5,853 genes. The genome of Pseudomonas sp. PMCC200367 was composed of a circular chromosome of 6,360,061 bp with a G + C content of 58.68% and contained 5,801 genes. Not only prophages but also genomic islands were identified in the two Pseudomonas strains. No plasmids were observed. All genes of a complete set of denitrification pathways as well as various putative cold adaptation and heavy metal resistance genes in the genomes were identified and analyzed. These genes were usually detected on genomic islands in bacterial genomes. CONCLUSIONS: These analytical results provide insights into the genomic basis of microbial denitrification in cold environments, indicating the potential of Arctic Pseudomonas strains in nitrogen removal from sewage effluents at low temperatures.
Subject(s)
Denitrification , Sewage , Comparative Genomic Hybridization , Genomics , Nitrogen , Pseudomonas/geneticsABSTRACT
BACKGROUND: Ferroptosis, which is characterized by lipid peroxidation and iron accumulation, is closely associated with the pathogenesis of acute renal injury (AKI). Cyanidin-3-glucoside (C3G), a typical flavonoid that has anti-inflammatory and antioxidant effects on ischemiaâreperfusion (I/R) injury, can induce AMP-activated protein kinase (AMPK) activation. This study aimed to show that C3G exerts nephroprotective effects against I/R-AKI related ferroptosis by regulating the AMPK pathway. METHODS: Hypoxia/reoxygenation (H/R)-induced HK-2 cells and I/R-AKI mice were treated with C3G with or without inhibiting AMPK. The level of intracellular free iron, the expression of the ferroptosis-related proteins acyl-CoA synthetase long chain family member 4 (ACSL4) and glutathione peroxidase 4 (GPX4), and the levels of the lipid peroxidation markers 4-hydroxynonenal (4-HNE), lipid reactive oxygen species (ROS) and malondialdehyde (MDA) were examined. RESULTS: We observed the inhibitory effect of C3G on ferroptosis in vitro and in vivo, which was characterized by the reversion of excessive intracellular free iron accumulation, a decrease in 4-HNE, lipid ROS, MDA levels and ACSL4 expression, and an increase in GPX4 expression and glutathione (GSH) levels. Notably, the inhibition of AMPK by CC significantly abrogated the nephroprotective effect of C3G on I/R-AKI models in vivo and in vitro. CONCLUSION: Our results provide new insight into the nephroprotective effect of C3G on acute I/R-AKI by inhibiting ferroptosis by activating the AMPK pathway.
Subject(s)
Acute Kidney Injury , Ferroptosis , Reperfusion Injury , Animals , Mice , AMP-Activated Protein Kinases , Reactive Oxygen Species , Acute Kidney Injury/drug therapy , Acute Kidney Injury/etiology , Reperfusion Injury/drug therapy , Iron , Ischemia , LipidsABSTRACT
Members of the genus Pseudomonas have been frequently isolated from the marine environment, indicating their ecological role in native habitats. One bacterial strain, Pseudomonas sp. BSw22131, was isolated from seawater in Kongsfjorden, Svalbard. The bacterium can grow with algae-derived dimethylsulfoniopropionate (DMSP) as the sole carbon source. Here, we sequenced the complete genome of strain BSw22131, which contained a single circular chromosome of 5,739,290 (G + C content of 58.23 mol%) without any plasmids. A total of 5362 protein-coding genes, 65 tRNA genes, and 16 rRNA genes were obtained. Genome sequence analysis revealed that strain BSw22131 was not only a potential novel species of the genus Pseudomonas but also different from Pseudomonas sp. DMSP-1 that was isolated from the same habitat and also utilized DMSP as the sole carbon source for growth. The results can be helpful for understanding the catabolism of the genus Pseudomonas in sulfur cycling in the Arctic fjord ecosystem.
Subject(s)
Ecosystem , Sulfonium Compounds , Bacteria/genetics , Seawater/microbiology , Sulfonium Compounds/metabolism , PhylogenyABSTRACT
Members of the genus Devosia are known for their abilities to degrade deoxynivalenol (DON). The type strain Devosia beringensis S02T (= JCM 33772 = CCTCC AB 2019343) was isolated from sediment of the Bering Sea and identified in 2021. However, the genome sequence of D. beringensis S02T remains unclear, which complicates the exploration into the function and ecological role of this strain in marine sediment. The genome of D. beringensis S02T contained a 4,048,765 bp chromosome with a G + C content of 63.84 mol%. Potential genes involved in DON degradation were found in the genome. In addition, multiple genes involved in polysaccharide degradation, including agarose, chitin, carrageen, pectate, starch, and xylan, were also annotated in the genome. These findings indicated the potential of strain S02T to be used for DON degradation and its ecological function in the carbon cycle in marine sediment.
Subject(s)
Hyphomicrobiaceae , DNA, Bacterial/genetics , Hyphomicrobiaceae/genetics , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , TrichothecenesABSTRACT
Cisplatin is widely used in the treatment of solid tumors, but its application is greatly limited due to its nephrotoxicity; thus, there is still no effective medicine for the treatment of cisplatin-induced acute kidney injury (Cis-AKI). We previously identified that polydatin (PD) exerts nephroprotective effects by antioxidative stress in AKI models. Recent evidence suggests that oxidative stress-induced molecular events overlap with the process of ferroptosis and that there are common molecular targets, such as glutathione (GSH) depletion and lipid peroxidation. Nevertheless, whether the nephroprotective effect of PD is related to anti-ferroptosis remains unclear. In this study, the inhibitory effect of PD on ferroptosis was observed in both cisplatin-treated HK-2 cells (20 µM) in vitro and a Cis-AKI mouse model (20 mg/kg, intraperitoneally) in vivo, characterized by the reversion of excessive intracellular free iron accumulation and reactive oxygen species (ROS) generation, a decrease in malondialdehyde (MDA) content and GSH depletion, and an increase in glutathione peroxidase-4 (GPx4) activity. Remarkably, PD dose-dependently alleviated cell death induced by the system Xc- inhibitor erastin (10 µM), and the effect of the 40 µM dose of PD was more obvious than that of ferrostatin-1 (1 µM) and deferoxamine (DFO, 100 µM), classical ferroptosis inhibitors. Our results provide insight into nephroprotection with PD in Cis-AKI by inhibiting ferroptosis via maintenance of the system Xc--GSH-GPx4 axis and iron metabolism.
Subject(s)
Acute Kidney Injury/chemically induced , Cisplatin/adverse effects , Drugs, Chinese Herbal/therapeutic use , Ferroptosis/drug effects , Glucosides/therapeutic use , Stilbenes/therapeutic use , Animals , Drugs, Chinese Herbal/pharmacology , Glucosides/pharmacology , Humans , Male , Mice , Stilbenes/pharmacologyABSTRACT
Strain S02T was isolated from a surface sediment sample collected from the Bering Sea (64.3361° N, 170.9541° W). The cells were Gram-stain-negative, motile and rod-shaped. The temperature range for growth was 4-25 °C and the pH for growth was 5.5-9.0, with optimum growth occurring at 20-25 °C and pH 7.0-8.0. Growth occurred in the presence of 0-7â% (w/v) NaCl (optimum, 2-5â%). Strain S02T had menaquinone-8 as the major respiratory quinone and summed feature 8 (C18â:â1 ω7c and/or C18â:â1 ω6c), C16:0, C17â:â0 cyclo, summed feature 3 (C16â:â1 ω7c /C16â:â1 ω7c), C17â:â0 and C18â:â0 as major fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and two glycolipids. The genomic DNA G+C content was approximately 63.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S02T belonged to the genus Devosia. Strain S02T showed the highest sequence similarities to Devosia psychrophila Cr7-05T (97.5â%), Devosia naphthalenivorans CM5-1T (97.7â%), Devosia submarina KMM 9415T (97.4â%), Devosia epidermidihirudinis E84T (97.44â%), Devosia euplotis LIV5T (97.1â%) and Devosia limi DSM 17137T (96.7â%). On the basis of phylogenetic analyses and phenotypic characteristics, a novel species of the genus Devosia, Devosia beringensis sp. nov., is proposed, with the type strain S02T (=JCM 33772=CCTCC AB 2019343).
Subject(s)
Hyphomicrobiaceae/classification , Phylogeny , Seawater/microbiology , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/genetics , Fatty Acids/chemistry , Hyphomicrobiaceae/isolation & purification , Phospholipids/chemistry , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Vitamin K 2/analogs & derivatives , Vitamin K 2/chemistryABSTRACT
BACKGROUND: An epidemic of thunderstorm asthma in pediatric patients occurred in Yulin, a northwest city of China, on 11 September 2018. We described the epidemic and retrospectively analyzed the demographic and clinical aspects of the involved children. METHODS: The caseload data of patients were collected from the hospital information system in Yulin Pediatric Hospital. The detailed document of hospitalized children with thunderstorm asthma was sourced from the medical records. RESULTS: The mean number of daily visits to emergency/outpatient department and the daily admission to hospital were 2.7 and 16 times, respectively, than on the other days of September. A gender prominence of males was observed in both emergency/outpatient and inpatient department. Among the 51 hospitalized children with detailed medical records, 56% of them had never experienced or were diagnosed with asthma and 25% had confirmed diagnosis of asthma. Sixty-seven percent had a history of allergic rhinitis during August and September. Seventy-six percent of the hospitalized children presented as moderate asthma. Ninety-four percent of the pediatric patients had positive IgE against mugwort pollen and 78% were monosensitized to pollen. CONCLUSION: Thunderstorm asthma can affect children, especially who has allergic rhinitis or asthma without preventive management. Mugwort is also an aeroallergen in thunderstorm asthma attacks. IMPACT: Thunderstorm can induce asthma attacks in children with allergic rhinitis owing to mugwort and aggravate symptoms in children with confirmed diagnosis of asthma. Children with mugwort allergy are susceptible to thunderstorm asthma and a preponderance of boys was observed. Better identification of allergic children to mugwort, giving suitable protective measures during thunderstorm and standard therapy to existing allergic situation could be a benefit for children at risk of thunderstorm asthma.
Subject(s)
Asthma/epidemiology , Climatic Processes , Hospitalization , Pollen/immunology , Adolescent , Allergens , Child , Child, Preschool , China/epidemiology , Emergency Service, Hospital , Epidemics , Female , Humans , Immunoglobulin E , Inpatients , Male , Outpatients , Retrospective Studies , Risk Factors , Sex FactorsABSTRACT
A Gram-stain-negative, aerobic, non-motile, non-gliding, yellow-pigmented and rod-shaped bacterial strain, designated 1KV19T, was isolated from a surface sediment sample collected near a bay in the Arctic. Growth of strain 1KV19T occurred in 1-4â% (w/v) NaCl (optimum, 2â%), at 4-35 °C (optimum, 25-30 °C) and at pH 6.5-8.0 (optimum, pH 7.0-7.5). The phylogenetic trees based on the 16S rRNA gene sequences showed that strain 1KV19T was associated with the genus Lutibacter and had the highest 16S rRNA gene sequence similarity to Lutibacter oceani 325-5T with 98.1â% similarity. Similarity values between strain 1KV19T and the type strains of other Lutibacter species were in the range 95.9-97.6â%. The average nucleotide identity and digital DNA-DNA hybridization values between strain 1KV19T and related species of the genus Lutibacter were 76.4-79.1 and 19.9-22.3â%, respectively. The major cellular fatty acids of strain 1KV19T were iso-C15â:â0 3-OH, iso-C15â:â0 and iso-C16â:â1 H. The respiratory quinone was MK-6. The major polar lipids of strain 1KV19T were phosphatidylethanolamine, one unidentified aminolipid and two unidentified polar lipids. The phenotypic, genotypic and chemotaxonomic differences between strain 1KV19T and its phylogenetic relatives indicate that strain 1KV19T should be regarded as representing a novel species in the genus Lutibacter, for which the name Lutibacter citreus sp. nov. is proposed. The type strain is 1KV19T (=KCTC 62595T=MCCC 1H00307T).
Subject(s)
Flavobacteriaceae/classification , Geologic Sediments/microbiology , Phylogeny , Seawater/microbiology , Animals , Arctic Regions , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/genetics , Fatty Acids/chemistry , Flavobacteriaceae/isolation & purification , Nucleic Acid Hybridization , Phosphatidylethanolamines/blood , Pigmentation , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Svalbard , Vitamin K 2/analogs & derivatives , Vitamin K 2/chemistryABSTRACT
The genus Sulfitobacter has been mostly found in marine and hypersaline environments. Members of this genus were observed to be associated with marine microalgae by inducing cell death of algae and degrading of algae-derived dimethylsulfoniopropionate (DMSP). Here we reported the complete genome sequence of strain Sulfitobacter sp. BSw21498 isolated from seawater of Kongsfjorden, an Arctic fjord in Svalbard. The strain contained a circular chromosome of 3,097,372 bp with G+C content of 58.55 mol% and a plasmid of 147,547 bp with G+C content of 56.53 mol%. In particular, a gene for DMSP lyase DddL was found in the genome, rendering Sulfitobacter sp. strain BSw21498 one of the Rhodobacterales bacteria equipped with the potential for DMSP degradation.
Subject(s)
Genome, Bacterial , Rhodobacteraceae/genetics , Seawater/microbiology , Svalbard , Whole Genome SequencingABSTRACT
BACKGROUND: Spontaneous formation of urinoma is a rare condition, especially for pregnant women. We report a patient in the third trimester of pregnancy with a spontaneous renal rupture who then develops a urinoma from urine leaking into the perinephric space. CASE PRESENTATION: A 23-year-old primagravida was diagnosed with a spontaneous renal rupture and acute left loin pain accompanied by hematuria when she was 35 weeks pregnant. A sub-capsular perinephric cyst then developed to a size of 319 × 175 × 253 mm, and because of discomfort to the patient, we performed Cesarean section. After a healthy male newborn was delivered, fluid was suctioned from a large perirenal cyst that had an estimated size of 300 × 200 × 300 mm. A percutaneous nephrostomy tube was left in the cyst until CT showed no remaining fluid. In the six-month follow-up, the patient showed no perirenal extravasation according to an ultrasound scan, and the urine analysis and renal function tests were normal. CONCLUSION: Close follow-up should be recommended for the patient who has renal rupture after conservative therapy, especially for pregnant woman. CT or MRI should be considered in addition to utilizing ultrasound in the management of pregnant women who present with urinomas. Percutaneous nephrostomy is suggested as an appropriate treatment for large urinomas.
Subject(s)
Kidney Diseases/pathology , Pregnancy Complications/pathology , Urinoma/pathology , Cesarean Section , Female , Humans , Infant, Newborn , Kidney Diseases/complications , Live Birth , Male , Pregnancy , Pregnancy Complications/etiology , Pregnancy Trimester, Third , Rupture, Spontaneous , Urinoma/etiology , Young AdultABSTRACT
A Gram-stain-negative, non-motile, aerobic, short rod-shaped bacterium, designated OD32T, was isolated from a soil sample taken from the rhizosphere of Silene acaulis collected from the Arctic tundra. The novel strain, OD32T, was able to grow at 15-37 °C (optimum, 33 °C), pH 6.5-9.5 (pH 7.5-8.0) and 0-0.5â% NaCl (0â%, w/v). A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain OD32T was most closely related to the genus Deinococcus; it shared the highest sequence similarity (95.7â%) with Deinococcus grandis ATCC 43672T. Genomic DNA G+C content of the strain OD32T was 68.2 mol%. The predominant respiratory quinone was menaquinone 8 (MK-8). The major fatty acids were summed feature 3 (C16â:â1 ω7c/C16â:â1 ω6c), C15â:â1 ω6c, C17â:â1 ω6c, C17â:â0, C16â:â0 and iso-C17â:â0. Based on phylogenetic inference and genotypic characteristics, strain OD32T represents a novel species of the genus Deinococcus, for which the name Deinococcus arcticus sp. nov. is proposed. The type strain is OD32T (=KCTC 33972T=CICC 24671T).
Subject(s)
Deinococcus/classification , Phylogeny , Rhizosphere , Silene/microbiology , Soil Microbiology , Tundra , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/genetics , Deinococcus/isolation & purification , Fatty Acids/chemistry , Genotype , Phospholipids/chemistry , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , SvalbardABSTRACT
A Gram-stain-negative, rod-shaped, red-coloured and aerobic bacterium, designated 2b14T, was isolated from rhizosphere soil of Saxifraga oppositifolia sampled at the Chinese Arctic Yellow River Station in Norway. Optimal growth occurred at 28 °C (range, 4-37 °C) and pH 7.0-7.5 (pH 6.5-8.5). The strain could tolerate up to 2.5â% (w/v) NaCl concentration. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 2b14Thad the highest similarity value of 96.0â% to Pontibacter diazotrophicus CCTCC AB 2013049T. The major fatty acids were summed feature 4 (anteiso-C17â:â1 B and/or iso-C17â:â1 I), iso-C15â:â0 and iso-C17â:â0 3-OH. The major polar lipid was found to be phosphatidylethanolamine. The genomic DNA G+C content of strain 2b14T was 45.5 mol%. The sole respiratory quinone was MK-7. The combined results of physiological, genotypic, phylogenetic and chemotaxonomic analyses showed that strain 2b14T represents a novel species within the genus Pontibacter, for which the name Pontibacter arcticus sp. nov. is proposed. The type strain is 2b14T (=KCTC 62596T=MCCC 1H00304T).
Subject(s)
Bacteroidetes/classification , Phylogeny , Rhizosphere , Saxifragaceae/microbiology , Soil Microbiology , Bacterial Typing Techniques , Bacteroidetes/isolation & purification , Base Composition , DNA, Bacterial/genetics , Fatty Acids/chemistry , Norway , Phosphatidylethanolamines/chemistry , Pigmentation , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Vitamin K 2/analogs & derivatives , Vitamin K 2/chemistryABSTRACT
A Gram-negative, aerobic, non-motile, pink and rod-shaped bacterium, designated E01020T, was isolated from soil collected from the Chinese Great Wall Station, Antarctica. Comparative analysis of 16S rRNA gene sequences revealed that strain E01020T is a member of the genus Pedobacter, related to Pedobacter alluvionis DSM 19624T (96.8% similarity), Pedobacter agri JCM 15120T (96.5% similarity) and Pedobacter chinensis JDX94T (96.3% similarity). The dDDH values and ANI values of strain E01020T with closely related strains indicate that it can be distinguished from them as a novel species. The DNA G+C content was determined to be 35.2 mol%. The growth of strain E01020T was observed at 4-25 °C (optimal 20 °C), in the presence of 0-1% NaCl (w/v, optimal 0%) and at pH 6.0-8.0 (optimal pH 7.0). Strain E01020T was found to contained menaquinon-7 (MK-7) as only respiratory quinone, iso-C15:0, iso-C17:0 3-OH and Summed feature 3 (C16:1ω6c and/or C16:1ω7c) as major fatty acids. The major polar lipids were phosphatidylethanolamine, one unidentified lipid and two unidentified aminolipids. On the basis of the results of the phylogenetic and phenotypic analyses, it was suggested that strain E01020T represents a novel species of the genus Pedobacter, for which the name Pedobacter changchengzhani sp. nov. is proposed. The type strain is E01020T (= KCTC 62990T = MCCC 1H00357T).
Subject(s)
Bacterial Typing Techniques , Pedobacter/classification , Pedobacter/isolation & purification , Phylogeny , Soil Microbiology , Aerobiosis , Antarctic Regions , Base Composition , Cluster Analysis , Cytosol/chemistry , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Fatty Acids/analysis , Hydrogen-Ion Concentration , Pedobacter/genetics , Pedobacter/physiology , Quinones/analysis , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Sodium Chloride/metabolism , TemperatureABSTRACT
Fjords and continental shelves represent distinct marine ecosystems in the pan-arctic region. Kongsfjorden is a glacial fjord that is located on the west coast of Svalbard, and is influenced by both Atlantic and Arctic water masses. The Bering Sea consists of a huge continental shelf in the northeast and a deep ocean basin in the southwest, and is influenced by Pacific water. Microbial community compositions of Arctic sediment samples BJ4 from outer basin and BJ36 from inner basin of Kongsfjorden and sub-Arctic samples NEC5 from shallow shelf and DBS1 from deep basin region of the northern Bering Sea were investigated using 454 pyrosequencing of archaeal and bacterial 16S rRNA genes. Most archaeal sequences in the sediments were related to Thaumarchaeota, though Euryarchaeota were more abundant in the Arctic glacier-influencing inner basin sediment BJ36. Thaumarchaeota Group C3 was the dominant archaeal population in all samples. Proteobacteria and Bacteroidetes dominated the sediment bacterial communities. Acidobacteria and Actinobacteria were also dominant in the northern Bering Sea samples. Alphaproteobacteria and Epsilonproteobacteria were the two main classes in Kongsfjorden sediment bacterial communities while Deltaproteobacteria and Gammaproteobacteria were dominant in the northern Bering Sea sediments. Differences in the presence and abundance of other dominant archaeal and bacterial populations were observed among sediment samples. In contrast to archaeal community differences that the Arctic BJ36 archaeal community was distinct from the sub-Arctic sediments and the Arctic outer basin sediment BJ4, cluster analysis based on bacterial OTU (operational taxonomic unit) distributions indicated that the Arctic and sub-Arctic bacterial communities segregated from one another. These results suggest that the sediment archaeal and bacterial community compositions can be driven by different environmental factors. Differences in the presence and abundance of particular archaeal species (e.g., Candidatus Nitrosopumilus and Methanococcoides) or bacterial species (e.g., Sulfurimonas, Sulfurovum, and Desulfobulbaceae) involved in biogeochemical cycles were also observed among sediment samples. At the same time, despite the community variation, some phylotypes (e.g., Marinicella) were dominant in all sediments. This study indicates diverse microbial communities inhabiting pan-arctic marine sediments, and highlights potential roles for Archaea and Bacteria in global biogeochemical cycles in these environments.
ABSTRACT
Dimethylsulfoniopropionate (DMSP), which is the major source of organic sulfur in the world's oceans, plays a significant role in the global sulfur cycle. This compound is rapidly degraded by marine bacteria either by cleavage to dimethylsulfide (DMS) or demethylation to 3-methylmercaptopropionate (MMPA). The diversity of genes encoding bacterial demethylation (dmdA) and DMS production (dddL and dddP) were measured in Arctic Kongsfjorden. Both dmdA and dddL genes were detected in all stations along a transect from the outer to the inner fjord, while dddP gene was only found in the outer and middle parts of the fjord. The dmdA gene was completely confined to the Roseobacter clade, while the dddL gene was confined to the genus Sulfitobacter. Although the dddP gene pool was also dominated by homologs from the Roseobacter clade, there were a few dddP genes showing close relationships to both Alphaproteobacter and Gammaproteobacter. The results of this study suggest that the Roseobacter clade may play an important role in DMSP catabolism via both demethylation and cleavage pathways in surface waters of Kongsfjorden during summer.
Subject(s)
Genes, Bacterial , Seawater/microbiology , Sulfonium Compounds/metabolism , Arctic Regions , Bacteria/genetics , Bacteria/isolation & purification , Bacteria/metabolism , Biodegradation, Environmental , DNA, Bacterial/genetics , Genetic Variation , Phylogeny , Propionates/metabolism , Rhodobacteraceae/genetics , Rhodobacteraceae/metabolism , Roseobacter/genetics , Roseobacter/metabolism , Sulfhydryl Compounds/metabolism , Sulfides/metabolism , Sulfur/metabolism , Water Pollutants, Chemical/metabolismABSTRACT
A Gram-stain-negative, non-motile, non-spore-forming, non-pigmented, oxidase- and catalase-positive bacterial strain, designated BIc20019T, was isolated from the ice core of Austre Lovénbreen in Ny-Ålesund, Svalbard. The temperature and NaCl ranges for growth were 4-34 °C (optimum, 25-29 °C) and 0-8% (w/v) (optimum, 2-4%). Analysis of the 16S rRNA gene sequence indicated that strain BIc20019T belonged to the genus Psychrobacter and was closely related to Psychrobacter arcticus 273-4T, Psychrobacter cryohalolentis K5T, 'Psychrobacter fjordensis' BSw21516B, Psychrobacter fozii LMG 21280T, Psychrobacter luti LMG 21276T and Pyschrobacter okhotskensis MD17T at greater than 99% similarity. Phylogenetic analysis based on gyrB gene sequences revealed highest similarity (93.6%) to P. okhotskensis MD17T. However, DNA hybridization experiments revealed a low level of DNA-DNA relatedness (<59%) between strain BIc20019T and its closest relatives. Strain BIc20019T contained ubiquinone-8 (Q-8) as the predominant respiratory quinone, and C18:1ω9c and summed feature 3 (C16:1ω7c and/or iso-C15:0 2-OH) as the major fatty acids. It had a DNA G+C content of 46.3âmol%. The polar lipid profile of strain BIc20019T was mainly composed of phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Owing to the differences in phenotypic and chemotaxonomic characteristics, phylogenetic analysis based on 16S rRNA gene and gyrB gene sequences, and DNA-DNA relatedness data, the isolate merits classification within a novel species for which the name Psychrobacter glaciei sp. nov. is proposed. The type strain is BIc20019T (=KCTC 42280T = CCTCC AB 2014019T).
Subject(s)
Ice Cover/microbiology , Phylogeny , Psychrobacter/classification , Arctic Regions , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/genetics , Fatty Acids/chemistry , Genes, Bacterial , Molecular Sequence Data , Nucleic Acid Hybridization , Phospholipids/chemistry , Psychrobacter/genetics , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Svalbard , Ubiquinone/chemistryABSTRACT
A Gram-negative, non-motile, non-spore-forming, psychrotolerant and halotolerant bacterium designated BSw21516B(T), was obtained from seawater in Kongsfjorden, a glacial fjord in the Arctic Svalbard and subjected to taxonomic analysis using a polyphasic approach. This bacterium was observed to optimally grow at 25-29 °C; between at 4 and 34 °C, but not at >35 °C; and in the presence of 0-8 % (w/v) NaCl at an optimum concentration of 2-5 % (w/v) NaCl. Strain BSw21516B(T) was found to contain Ubiquinone-8 (Q-8) as a predominant respiratory lipoquinone and C18:1 ω9c and summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH) as predominant cellular fatty acids. Phylogenetic analysis of 16S rRNA and gyrB gene sequences showed that this isolate belongs to the genus Psychrobacter and is closely related to Psychrobacter fozii LMG 21280(T), which was isolated from a sediment sample in Antarctica. DNA hybridization experiments revealed a low level of DNA-DNA relatedness (less than 58.6 %) between strain BSw21516B(T) and its closest relatives. Based on these results a new species Psychrobacter fjordensis sp. nov. is proposed (type strain BSw21516B(T) = KCTC 42279(T) = CCTCC AB 2014020(T)).
Subject(s)
Psychrobacter/classification , Psychrobacter/isolation & purification , Seawater/microbiology , Arctic Regions , Bacterial Typing Techniques , Cluster Analysis , Cytosol/chemistry , DNA Gyrase/genetics , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Estuaries , Fatty Acids/analysis , Molecular Sequence Data , Nucleic Acid Hybridization , Phylogeny , Psychrobacter/genetics , Psychrobacter/physiology , Quinones/analysis , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Sodium Chloride/metabolism , Svalbard , TemperatureABSTRACT
A pink-pigmented, non-motile, coccoid bacterial strain, designated G3-6-20(T), was isolated from a soil sample collected in the Grove Mountains, East Antarctica. This strain was resistant to UV irradiation (810 J m(-2)) and slightly more sensitive to desiccation as compared with Deinococcus radiodurans. Phylogenetic analyses based on the 16S rRNA gene sequence of the isolate indicated that the organism belongs to the genus Deinococcus. Highest sequence similarities were with Deinococcus ficus CC-FR2-10(T) (93.5 %), Deinococcus xinjiangensis X-82(T) (92.8 %), Deinococcus indicus Wt/1a(T) (92.5 %), Deinococcus daejeonensis MJ27(T) (92.3 %), Deinococcus wulumuqiensis R-12(T) (92.3 %), Deinococcus aquaticus PB314(T) (92.2 %) and Deinococcus radiodurans DSM 20539(T) (92.2 %). Major fatty acids were C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), anteiso-C15 : 0 and C16 : 0. The G+C content of the genomic DNA of strain G3-6-20(T) was 63.1 mol%. Menaquinone 8 (MK-8) was the predominant respiratory quinone. Based on its phylogenetic position, and chemotaxonomic and phenotypic characteristics, strain G3-6-20(T) represents a novel species of the genus Deinococcus, for which the name Deinococcus antarcticus sp. nov. is proposed. The type strain is G3-6-20(T) (â=âDSM 27864(T)â= CCTCC AB 2013263(T)).