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1.
Aequorivita iocasae sp. nov., a halophilic bacterium isolated from sediment collected at a cold seep field in the South China Sea.
Zhang, H, Wang, H, Cao, L, Chen, H, Zhong, Z, Wang, M, Lian, C, Liu, R, Zhou, L, Li, C
International journal of systematic and evolutionary microbiology. 2022;(2)
Abstract
A moderately halophilic bacterium, designated strain KX20305T, was isolated from sediment collected from a cold seep field in the South China Sea. Cells of strain KX20305T were Gram-stain-negative, rod-shaped, non-motile, facultatively anaerobic, oxidase- and catalase-positive, and grew optimally at 25-30 °C, pH 6.0-8.0 and with 3-6 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain KX20305T grouped with members of the genus Aequorivita, including Aequorivita aquimaris D-24T (98.3 % sequence similarity), Aequorivita vladivostokensis KMM 3516T (98.1 %) and Aequorivita echinoideorum CC-CZW007T (97.5 %). Genome sequencing of strain KX20305T revealed a genome size of 3.35 Mb and a DNA G+C content of 38.71 mol%. Genomic average nucleotide identity (orthoANI) values of strain KX20305T with A. aquimaris D-24T, A. vladivostokensis KMM 3516T and A. echinoideorum JCM 30378T were 83.8, 81.7 and 75.4 %, respectively, while in silico DNA-DNA hybridization (GGDC) values for strain KX20305T with these strains were 27.2, 25.0 and 19.6 %, respectively. The major fatty acids of strain KX20305T were iso-C15 : 0, iso-C17 : 0 3-OH and 10-methyl C16 : 0/iso-C17 : 1 ω9c. The predominant respiratory quinone was menaquinone-6 (MK-6). The polar lipids mainly comprised phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids. Based on comparative analysis of phylogenetic, phylogenomic, phenotypic and chemotaxonomic characteristics, strain KX20305T represents a novel species of the genus Aequorivita, for which the name Aequorivita iocasae sp. nov. is proposed. The type strain is KX20305T (=KCTC 82699T=MCCC 1K06238T=JCM 34635T).
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2.
Formation of cadmium sulfide nanoparticles mediates cadmium resistance and light utilization of the deep-sea bacterium Idiomarina sp. OT37-5b.
Ma, N, Sha, Z, Sun, C
Environmental microbiology. 2021;(2):934-948
Abstract
Heavy metal is one of the major factors threatening the survival of microorganisms. Here, a deep-sea bacterium designated Idiomarina sp. OT37-5b possessing strong cadmium (Cd) tolerance was isolated from a typical hydrothermal vent. Both the Cd-resistance and removal efficiency of Idiomarina sp. OT37-5b were significantly promoted by the supplement of cysteine and meanwhile large amount of CdS nanoparticles were observed. Production of H2 S from cysteine catalysed by methionine gamma-lyase was further demonstrated to contribute to the formation of CdS nanoparticles. Proteomic results showed the addition of cysteine effectively enhanced the efflux of Cd, improved the activities of reactive oxygen species scavenging enzymes, and thereby boosted the nitrogen reduction and energy production of Idiomarina sp. OT37-5b. Notably, the existence of CdS nanoparticles obviously promoted the growth of Idiomarina sp. OT37-5b when exposed to light, indicating this bacterium might grab light energy through CdS nanoparticles. Proteomic analysis revealed the expression levels of essential components for light utilization including electron transport, cytochrome complex and F-type ATPase were significantly up-regulated, which strongly suggested the formation of CdS nanoparticles promoted light utilization and energy production. Our results provide a good model to investigate the uncovered mechanisms of self-photosensitization of nonphotosynthetic bacteria for light-to-chemical production in the deep biosphere.
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3.
The Complexity of Spills: The Fate of the Deepwater Horizon Oil.
Passow, U, Overton, EB
Annual review of marine science. 2021;:109-136
Abstract
The Deepwater Horizon oil spill was the largest, longest-lasting, and deepest oil accident to date in US waters. As oil and natural gas jetted from release points at 1,500-m depth in the northern Gulf of Mexico, entrainment of the surrounding ocean water into a buoyant plume, rich in soluble hydrocarbons and dispersed microdroplets of oil, created a deep (1,000-m) intrusion layer. Larger droplets of liquid oil rose to the surface, forming a slick of mostly insoluble, hydrocarbon-type compounds. A variety of physical, chemical, and biological mechanisms helped to transform, remove, and redisperse the oil and gas that was released. Biodegradation removed up to 60% of the oil in the intrusion layer but was less efficient in the surface slick, due to nutrient limitation. Photochemical processes altered up to 50% (by mass) of the floating oil. The surface oil expression changed daily due to wind and currents, whereas the intrusion layer flowed southwestward. A portion of the weathered surface oil stranded along shorelines. Oil from both surface and intrusion layers were deposited onto the seafloor via sinking marine oil snow. The biodegradation rates of stranded or sedimented oil were low, with resuspension and redistribution transiently increasing biodegradation. The subsequent research efforts increased our understanding of the fate of spilled oil immensely, with novel insights focusing on the importance of photooxidation, the microbial communities driving biodegradation, and the formation of marine oil snow that transports oil to the seafloor.
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4.
New Microbial Biodiversity in Marine Sediments.
Baker, BJ, Appler, KE, Gong, X
Annual review of marine science. 2021;:161-175
Abstract
Microbes in marine sediments represent a large portion of the biosphere, and resolving their ecology is crucial for understanding global ocean processes. Single-gene diversity surveys have revealed several uncultured lineages that are widespread in ocean sediments and whose ecological roles are unknown, and advancements in the computational analysis of increasingly large genomic data sets have made it possible to reconstruct individual genomes from complex microbial communities. Using these metagenomic approaches to characterize sediments is transforming our view of microbial communities on the ocean floor and the biodiversity of the planet. In recent years, marine sediments have been a prominent source of new lineages in the tree of life. The incorporation of these lineages into existing phylogenies has revealed that many belong to distinct phyla, including archaeal phyla that are advancing our understanding of the origins of cellular complexity and eukaryotes. Detailed comparisons of the metabolic potentials of these new lineages have made it clear that uncultured bacteria and archaea are capable of mediating key previously undescribed steps in carbon and nutrient cycling.
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5.
Shewanella nanhaiensis sp. nov., a marine bacterium isolated from sediment of South China Sea, and emended descriptions of Shewanella woodyi, Shewanella hanedai and Shewanella canadensis.
Cao, WR, Li, X, Sun, YY, Jiang, MY, Xu, XD, Li, YJ
International journal of systematic and evolutionary microbiology. 2021;(12)
Abstract
A Gram-stain-negative, motile, facultative anaerobic and rod-shaped bacterium, designated strain NR704-98T, was isolated from marine sediment of the northern South China Sea. Cells were positive for oxidase and catalase activity. Growth was observed at 4-30 °C (optimum 20-25 °C), at pH 6-9 (pH 7) and with 0.5-7 % NaCl (2 %). The 16S rRNA gene-based phylogenetic analysis revealed that the nearest phylogenetic neighbours of strain NR704-98T were Shewanella woodyi MS32T (97.9 %), Shewanella hanedai 281T (97.1 %), Shewanella sediminis HAW-EB3T (96.8 %) and Shewanella canadensis HAW-EB2T (96.7 %). Based on the results of phylogenomic analysis, the average nucleotide identity and the digital DNA-DNA hybridization values between strain NR704-98T and the previously mentioned type strains of species of the genus Shewanella were in the range of 74.9-93.1 % and 20.6-51.4 %, respectively. The respiratory quinones were Q-7 and Q-8. The predominant fatty acids (>10 %) of strain NR704-98T were C16 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and iso-C15 : 0. Phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminophospholipids and five unidentified lipids were detected in strain NR704-98T. Based on the phylogenetic and phenotypic characteristics, strain NR704-98T is considered to represent a novel species of the genus Shewanella, for which the name Shewanella nanhaiensis sp. nov. is proposed. The type strain is NR704-98T (=KCTC 82799T=MCCC 1K06091T).
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6.
Functional characterisation of substrate-binding proteins to address nutrient uptake in marine picocyanobacteria.
Ford, BA, Sullivan, GJ, Moore, L, Varkey, D, Zhu, H, Ostrowski, M, Mabbutt, BC, Paulsen, IT, Shah, BS
Biochemical Society transactions. 2021;(6):2465-2481
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Abstract
Marine cyanobacteria are key primary producers, contributing significantly to the microbial food web and biogeochemical cycles by releasing and importing many essential nutrients cycled through the environment. A subgroup of these, the picocyanobacteria (Synechococcus and Prochlorococcus), have colonised almost all marine ecosystems, covering a range of distinct light and temperature conditions, and nutrient profiles. The intra-clade diversities displayed by this monophyletic branch of cyanobacteria is indicative of their success across a broad range of environments. Part of this diversity is due to nutrient acquisition mechanisms, such as the use of high-affinity ATP-binding cassette (ABC) transporters to competitively acquire nutrients, particularly in oligotrophic (nutrient scarce) marine environments. The specificity of nutrient uptake in ABC transporters is primarily determined by the peripheral substrate-binding protein (SBP), a receptor protein that mediates ligand recognition and initiates translocation into the cell. The recent availability of large numbers of sequenced picocyanobacterial genomes indicates both Synechococcus and Prochlorococcus apportion >50% of their transport capacity to ABC transport systems. However, the low degree of sequence homology among the SBP family limits the reliability of functional assignments using sequence annotation and prediction tools. This review highlights the use of known SBP structural representatives for the uptake of key nutrient classes by cyanobacteria to compare with predicted SBP functionalities within sequenced marine picocyanobacteria genomes. This review shows the broad range of conserved biochemical functions of picocyanobacteria and the range of novel and hypothetical ABC transport systems that require further functional characterisation.
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7.
Impact of intensifying nitrogen limitation on ocean net primary production is fingerprinted by nitrogen isotopes.
Buchanan, PJ, Aumont, O, Bopp, L, Mahaffey, C, Tagliabue, A
Nature communications. 2021;(1):6214
Abstract
The open ocean nitrogen cycle is being altered by increases in anthropogenic atmospheric nitrogen deposition and climate change. How the nitrogen cycle responds will determine long-term trends in net primary production (NPP) in the nitrogen-limited low latitude ocean, but is poorly constrained by uncertainty in how the source-sink balance will evolve. Here we show that intensifying nitrogen limitation of phytoplankton, associated with near-term reductions in NPP, causes detectable declines in nitrogen isotopes (δ15N) and constitutes the primary perturbation of the 21st century nitrogen cycle. Model experiments show that ~75% of the low latitude twilight zone develops anomalously low δ15N by 2060, predominantly due to the effects of climate change that alter ocean circulation, with implications for the nitrogen source-sink balance. Our results highlight that δ15N changes in the low latitude twilight zone may provide a useful constraint on emerging changes to nitrogen limitation and NPP over the 21st century.
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8.
Aurantimonas marina sp. nov., isolated from deep-sea sediment.
Song, L, Liu, H, Sun, Q, Dong, X, Zhou, Y
International journal of systematic and evolutionary microbiology. 2021;(8)
Abstract
A novel bacterial strain, designated SW136T, was isolated from a deep-sea sediment sample collected from the South China Sea. Cells were Gram-stain-negative, aerobic, catalase-positive and oxidase-positive. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SW136T represented a novel member of the genus Aurantimonas, forming a distinct cluster with 'Aurantimonas litoralis', Aurantimonas coralicida and Aurantimonas manganoxydans (98.2, 98.1 and 97.9% sequence similarity, respectively). The predominant cellular fatty acid of strain SW136T was C18 : 1 ω7c. Strain SW136T contained ubiquinone-10 as the dominant respiratory quinone, and diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. The genomic DNA G+C content was 64.3 mol%. The average nucleotide identity and digital DNA-DNA hybridization values of strain SW136T with A. coralicida CGMCC 1.12222T and A. manganoxydans CGMCC 1.12225T were 78.8 and 78.6 % and 21.5 and 25.5 %, respectively. On the basis of phylogenetic inference and phenotypic characteristics, we propose that strain SW136T represents a novel species of the genus Aurantimonas, with the name Aurantimonas marina sp. nov. The type strain is SW136T (=CGMCC 1.17725T=KCTC 82366T).
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9.
Description of Novosphingopyxis iocasae sp. nov., isolated from deep sea sediment from the Mariana Trench, and emended description of the genus Novosphingopyxis.
Zhou, HZ, Zhang, J, Sun, QL
International journal of systematic and evolutionary microbiology. 2021;(7)
Abstract
In this study, we reported a Gram-stain-negative, orange-coloured, rod-shaped, motile and faculatively anaerobic bacterium named strain PB63T, which was isolated from the deep-sea sediment from the Mariana Trench. Growth of PB63T occurred at 10-35 °C (optimum, 28 °C), pH 5.0-8.0 (optimum, 5.0-6.0) and with 0-7 % (w/v) NaCl (optimum, 2-3 %). The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that PB63T represented a member of the genus Novosphingopyxis and was closely related to Novosphingopyxis baekryungensis DSM 16222T (97.9 % sequence similarity). PB63T showed tolerance to a variety of heavy metals, including Co2+, Zn2+, Mn2+ and Cu2+. The complete genome of PB63T was obtained, and many genes involved in heavy metal resistance were found. The genomic DNA G+C content of PB63T was 62.8 mol%. The predominant respiratory quinone of PB63T was ubiquinone-10 (Q-10). The polar lipids of PB63T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, glycolipid, phosphatidylcholines and three unidentified lipids. The major fatty acids of PB63T included summed feature 8 (C18 : 1ω7c or/and C18 : 1ω6c), C14 : 0 2-OH, 11-methyl C18 : 1ω7c, C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C17 : 1ω6c. The results of phylogenetic, physiological, biochemical and morphological analyses indicated that strain PB63T represents a novel species of the genus Novosphingopyxis, and the name Novosphingopyxis iocasae sp. nov. is proposed with the type species PB63T (=CCTCC AB 2019195T=JCM 34178T).
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10.
Thermococcus aciditolerans sp. nov., a piezotolerant, hyperthermophilic archaeon isolated from a deep-sea hydrothermal vent chimney in the Southwest Indian Ridge.
Li, XG, Tang, HZ, Zhang, WJ, Qi, XQ, Qu, ZG, Xu, J, Wu, LF
International journal of systematic and evolutionary microbiology. 2021;(8)
Abstract
A hyperthermophilic, strictly anaerobic archaeon, designated strain SY113T, was isolated from a deep-sea hydrothermal vent chimney on the Southwest Indian Ridge at a water depth of 2770 m. Enrichment and isolation of strain SY113T were performed at 85 °C at 0.1 MPa. Cells of strain SY113T were irregular motile cocci with peritrichous flagella and generally 0.8-2.4 µm in diameter. Growth was observed at temperatures between 50 and 90 °C (optimum at 85 °C) and under hydrostatic pressures of 0.1-60 MPa (optimum, 27 MPa). Cells of SY113T grew at pH 4.0-9.0 (optimum, pH 5.5) and a NaCl concentration of 0.5-5.5 % (w/v; optimum concentration, 3.0 % NaCl). Strain SY113T was an anaerobic chemoorganoheterotroph and grew on complex proteinaceous substrates such as yeast extract and tryptone, as well as on maltose and starch. Elemental sulphur stimulated growth, but not obligatory for its growth. The G+C content of the genomic DNA was 55.0 mol%. Phylogenetic analysis of the 16S rRNA sequence of strain SY113T showed that the novel isolate belonged to the genus Thermococcus. On the basis of physiological characteristics, average nucleotide identity values and in silico DNA-DNA hybridization results, we propose a novel species, named Thermococcus aciditolerans sp. nov. The type strain is SY113T (=MCCC 1K04190T=JCM 39083T).