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Zhu L, Feng S, Li Y, Sun X, Sui Q, Chen B, Qu K, Xia B. Physiological and transcriptomic analysis reveals the toxic and protective mechanisms of marine microalga Chlorella pyrenoidosa in response to TiO 2 nanoparticles and UV-B radiation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169174. [PMID: 38072255 DOI: 10.1016/j.scitotenv.2023.169174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/28/2023] [Accepted: 12/05/2023] [Indexed: 12/17/2023]
Abstract
Concerns have been raised regarding the adverse effects of nanoparticles (NPs) on marine organisms, as an increasing number of NPs inevitably enter the marine environment with the development of nanotechnology. Owing to the photocatalytic properties, TiO2 NPs' toxicity may be aggravated by enhanced UV-B resulting from stratospheric ozone depletion. However, the molecular mechanisms of phytoplankton in response to TiO2 NPs under UV-B remains poorly understood. In this study, we integrated whole transcriptome analysis with physiological data to provide understanding on the toxic and protective mechanisms of marine Chlorella pyrenoidosa in response to TiO2 NPs under UV-B. The results indicated that the changes in gene expression could be related to the growth inhibition and TiO2 NP internalization in C. pyrenoidosa, and several molecular mechanisms were identified as toxicity response to TiO2 NPs and UV-B. Differential expression of genes involved in glycerophospholipids metabolism indicated that cell membrane disruption allowed TiO2 NPs to enter the algal cell under UV-B exposure, although the up-regulation of genes involved in the general secretory dependent pathway and the ATP-binding cassette transporter family drove cellular secretion of extracellular polymeric substances, acting as a barrier that prevent TiO2 NP internalization. The absence of changes in gene expression related to the antioxidant system may be responsible for the severe oxidative stress observed in algal cells following exposure to TiO2 NPs under UV-B irradiation. Moreover, differential expression of genes involved in pathways such as photosynthesis and energy metabolism were up-regulated, including the light-harvesting, photosynthetic electron transport coupled to photophosphorylation, carbon fixation, glycolysis, pentose phosphate pathway, tricarboxylic acid cycle, and oxidative phosphorylation, indicating that more energy and metabolites were supplied to cope with the toxicity of TiO2 NPs and UV-B. The obtained results provide valuable information on the molecular mechanisms of response of marine phytoplankton exposed to TiO2 NPs and UV-B.
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Affiliation(s)
- Lin Zhu
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China
| | - Sulan Feng
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; School of Marine Technology and Geomatics, Jiangsu Ocean University, Lianyungang 222005, China
| | - Yu Li
- School of Marine Technology and Geomatics, Jiangsu Ocean University, Lianyungang 222005, China.
| | - Xuemei Sun
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China
| | - Qi Sui
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China
| | - Bijuan Chen
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China
| | - Keming Qu
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Bin Xia
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China.
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2
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Zhang X, Han W, Fan X, Wang Y, Xu D, Sun K, Wang W, Zhang Y, Ma J, Ye N. Gene duplication and functional divergence of new genes contributed to the polar acclimation of Antarctic green algae. MARINE LIFE SCIENCE & TECHNOLOGY 2023; 5:511-524. [PMID: 38045541 PMCID: PMC10689623 DOI: 10.1007/s42995-023-00203-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 10/12/2023] [Indexed: 12/05/2023]
Abstract
Psychrophilic microalgae successfully survive in the extreme and highly variable polar ecosystems, which represent the energy base of most food webs and play a fundamental role in nutrient cycling. The success of microalgae is rooted in their adaptive evolution. Revealing how they have evolved to thrive in extreme polar environments will help us better understand the origin of life in polar ecosystems. We isolated a psychrophilic unicellular green alga, Microglena sp. YARC, from Antarctic sea ice which has a huge genome. Therefore, we predicted that gene replication may play an important role in its polar adaptive evolution. We found that its protein-coding gene number significantly increased and the duplication time was dated between 37 and 48 million years ago, which is consistent with the formation of the circumpolar Southern Ocean. Most duplicated paralogous genes were enriched in pathways related to photosynthesis, DNA repair, and fatty acid metabolism. Moreover, there were a total of 657 Microglena-specific families, including collagen-like proteins. The divergence in the expression patterns of the duplicated and species-specific genes reflects sub- and neo-functionalization during stress acclimation. Overall, key findings from this study provide new information on how gene duplication and their functional novelty contributed to polar algae adaptation to the highly variable polar environmental conditions. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-023-00203-z.
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Affiliation(s)
- Xiaowen Zhang
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
- Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, 266200 China
| | - Wentao Han
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
| | - Xiao Fan
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
| | - Yitao Wang
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
| | - Dong Xu
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
| | - Ke Sun
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
| | - Wei Wang
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
| | - Yan Zhang
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
| | - Jian Ma
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
| | - Naihao Ye
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071 China
- Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, 266200 China
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Ren X, Yu Z, Song X, Zhu J, Wang W, Cao X. Effects of modified clay on the formation of Phaeocystis globosa colony revealed by physiological and transcriptomic analyses. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155985. [PMID: 35597349 DOI: 10.1016/j.scitotenv.2022.155985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/11/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
The harmful algal bloom (HAB) species Phaeocystis globosa is commonly observed in global temperate and tropical oceans, and colonies of P. globosa exhibit a dominant morphotype during blooms. The use of polyaluminium chloride modified clay (PAC-MC) is an effective mitigation strategy for P. globosa blooms. Although previous studies have found that PAC-MC can stimulate P. globosa colony formation at low concentrations and inhibit it at higher concentrations, the underlying mechanisms of these effects are poorly understood. Here, we comprehensively compared the physiochemical indices and transcriptomic response of residual P. globosa cells after treatment with two concentrations of PAC-MC. The results showed that PAC-MC induced oxidative stress, photosynthetic inhibition, and DNA damage in residual cells. Moreover, it could activate antioxidant responses and enhance the repair of photosynthetic structure and DNA damage in cells. The biosynthesis of polysaccharides was enhanced and genes associated with cell motility were down-regulated after treatment with PAC-MC, resulting in the accumulation of colonial matrixes. After treatment with a low concentration of PAC-MC (0.1 g/L), the residual cells were slightly stressed, including physical damage, oxidative stress and other damage, and polysaccharide synthesis was enhanced to promote colony formation to alleviate environmental stress. Moreover, the damage to residual cells was slight; thus, normal cell function provided abundant energy and matter for colony formation. After treatment with a high concentration of PAC-MC (0.5 g/L), the residual cells suffered severe damage, which disrupted normal physiological processes and inhibited cell proliferation and colony formation. The present study elucidated the concentration-dependent mechanism of PAC-MC affecting the formation of P. globosa colonies and provided a reference for the application of PAC-MC to control P. globosa blooms.
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Affiliation(s)
- Xiangzheng Ren
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Zhiming Yu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Xiuxian Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Jianan Zhu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Wentao Wang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Xihua Cao
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
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4
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The role of zinc in the adaptive evolution of polar phytoplankton. Nat Ecol Evol 2022; 6:965-978. [PMID: 35654896 DOI: 10.1038/s41559-022-01750-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/28/2022] [Indexed: 12/20/2022]
Abstract
Zinc is an essential trace metal for oceanic primary producers with the highest concentrations in polar oceans. However, its role in the biological functioning and adaptive evolution of polar phytoplankton remains enigmatic. Here, we have applied a combination of evolutionary genomics, quantitative proteomics, co-expression analyses and cellular physiology to suggest that model polar phytoplankton species have a higher demand for zinc because of elevated cellular levels of zinc-binding proteins. We propose that adaptive expansion of regulatory zinc-finger protein families, co-expanded and co-expressed zinc-binding proteins families involved in photosynthesis and growth in these microalgal species and their natural communities were identified to be responsible for the higher zinc demand. The expression of their encoding genes in eukaryotic phytoplankton metatranscriptomes from pole-to-pole was identified to correlate not only with dissolved zinc concentrations in the upper ocean but also with temperature, suggesting that environmental conditions of polar oceans are responsible for an increased demand of zinc. These results suggest that zinc plays an important role in supporting photosynthetic growth in eukaryotic polar phytoplankton and that this has been critical for algal colonization of low-temperature polar oceans.
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Gilbertson R, Langan E, Mock T. Diatoms and Their Microbiomes in Complex and Changing Polar Oceans. Front Microbiol 2022; 13:786764. [PMID: 35401494 PMCID: PMC8991070 DOI: 10.3389/fmicb.2022.786764] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/23/2022] [Indexed: 11/17/2022] Open
Abstract
Diatoms, a key group of polar marine microbes, support highly productive ocean ecosystems. Like all life on earth, diatoms do not live in isolation, and they are therefore under constant biotic and abiotic pressures which directly influence their evolution through natural selection. Despite their importance in polar ecosystems, polar diatoms are understudied compared to temperate species. The observed rapid change in the polar climate, especially warming, has created increased research interest to discover the underlying causes and potential consequences on single species to entire ecosystems. Next-Generation Sequencing (NGS) technologies have greatly expanded our knowledge by revealing the molecular underpinnings of physiological adaptations to polar environmental conditions. Their genomes, transcriptomes, and proteomes together with the first eukaryotic meta-omics data of surface ocean polar microbiomes reflect the environmental pressures through adaptive responses such as the expansion of protein families over time as a consequence of selection. Polar regions and their microbiomes are inherently connected to climate cycles and their feedback loops. An integrated understanding built on “omics” resources centered around diatoms as key primary producers will enable us to reveal unifying concepts of microbial co-evolution and adaptation in polar oceans. This knowledge, which aims to relate past environmental changes to specific adaptations, will be required to improve climate prediction models for polar ecosystems because it provides a unifying framework of how interacting and co-evolving biological communities might respond to future environmental change.
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Affiliation(s)
- Reuben Gilbertson
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Emma Langan
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom.,The Earlham Institute, Norwich Research Park, Norwich, United Kingdom
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
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6
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Li YP, You LX, Yang XJ, Yu YS, Zhang HT, Yang B, Chorover J, Feng RW, Rensing C. Extrapolymeric substances (EPS) in Mucilaginibacter rubeus P2 displayed efficient metal(loid) bio-adsorption and production was induced by copper and zinc. CHEMOSPHERE 2022; 291:132712. [PMID: 34715104 DOI: 10.1016/j.chemosphere.2021.132712] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 10/18/2021] [Accepted: 10/24/2021] [Indexed: 06/13/2023]
Abstract
Strains of the genus Mucilaginibacter, belonging to the phylum Bacteroidetes, have been noted for exhibiting high genome plasticity and for the vigorous production of extracellular polymeric substances (EPS). Here we analyzed the composition and properties of EPS generated by M. rubeus P2, isolated from a gold-copper mine and exhibiting extremely high resistance to multiple heavy metals. Production of EPS increased significantly upon exposure to elevated concentrations of Cu(II) and Zn(II), but not Au(III). In addition, the EPS produced by M. rubeus P2 displayed extremely high bio-adsorption of As(III), Cu(II) and Au(III), but not of Zn(II). Moreover, EPS production in Mucilaginibacter rubeus P2 exposed to 1 mM of Cu(II) was 8.5 times higher than EPS production in the same strain without metal (loid)-exposure. These findings constitute the basis for a future use of these EPS-overproducing bacteria in bioremediation of heavy metal contaminated environments. The functional groups, especially -SH, CO, and N-H/C-N in the fingerprint zone of glutathione (GSH) and polysaccharides-like components of EPS, were the main components of EPS involved in both Zn(II) and Cu(II) binding and removal. Around 31.22% and 5.74% of Cu(II)-treated EPS was shown to exist as (CO) structures and these structures were converted into C-OH and O-C-O upon exposure to Cu(II), respectively. In contrast, (C-OH/C-O-C/P-O-C) groups in EPS were observed to be positively correlated to increasing concentrations of Zn(II) in strain P2. Furthermore, the complete genome of M. rubeus P2 helped us to identify 350 genes involved in carbohydrate metabolism, some of which are predicted to be involved in EPS production and modification. This work describes the first detailed biochemical and biophysical analysis of EPS from any strain of Mucilaginibacter with unique heavy metal binding properties. The results will be useful for a better understanding of how microorganisms such as M. rubeus P2 adapt to heavy metal polluted environments and how this knowledge can potentially be harnessed in biotechnological applications such as industrial waste water purification, bioremediation of heavy metal contaminated soil and beneficial plant microbe interactions. The toolbox provided in this paper will provide a valuable basis for future studies.
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Affiliation(s)
- Yuan Ping Li
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Le Xing You
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Xiao Jun Yang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Yan Shuang Yu
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Hai Ting Zhang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Bing Yang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Jon Chorover
- Department of Environmental Science, University of Arizona, Tucson, AZ, 85719, USA
| | - Ren Wei Feng
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.
| | - Christopher Rensing
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.
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7
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Bilcke G, Osuna-Cruz CM, Santana Silva M, Poulsen N, D'hondt S, Bulankova P, Vyverman W, De Veylder L, Vandepoele K. Diurnal transcript profiling of the diatom Seminavis robusta reveals adaptations to a benthic lifestyle. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:315-336. [PMID: 33901335 DOI: 10.1111/tpj.15291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 06/12/2023]
Abstract
Coastal regions contribute an estimated 20% of annual gross primary production in the oceans, despite occupying only 0.03% of their surface area. Diatoms frequently dominate coastal sediments, where they experience large variations in light regime resulting from the interplay of diurnal and tidal cycles. Here, we report on an extensive diurnal transcript profiling experiment of the motile benthic diatom Seminavis robusta. Nearly 90% (23 328) of expressed protein-coding genes and 66.9% (1124) of expressed long intergenic non-coding RNAs showed significant expression oscillations and are predominantly phasing at night with a periodicity of 24 h. Phylostratigraphic analysis found that rhythmic genes are enriched in highly conserved genes, while diatom-specific genes are predominantly associated with midnight expression. Integration of genetic and physiological cell cycle markers with silica depletion data revealed potential new silica cell wall-associated gene families specific to diatoms. Additionally, we observed 1752 genes with a remarkable semidiurnal (12-h) periodicity, while the expansion of putative circadian transcription factors may reflect adaptations to cope with highly unpredictable external conditions. Taken together, our results provide new insights into the adaptations of diatoms to the benthic environment and serve as a valuable resource for the study of diurnal regulation in photosynthetic eukaryotes.
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Affiliation(s)
- Gust Bilcke
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
- Department of Biology, Protistology and Aquatic Ecology, Ghent University, Ghent, 9000, Belgium
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Ghent, 9000, Belgium
| | - Cristina Maria Osuna-Cruz
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
- Bioinformatics Institute Ghent, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
| | - Marta Santana Silva
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
| | - Nicole Poulsen
- B CUBE Center for Molecular Bioengineering, Technical University of Dresden, Tatzberg 41, Dresden, 01307, Germany
| | - Sofie D'hondt
- Department of Biology, Protistology and Aquatic Ecology, Ghent University, Ghent, 9000, Belgium
| | - Petra Bulankova
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
| | - Wim Vyverman
- Department of Biology, Protistology and Aquatic Ecology, Ghent University, Ghent, 9000, Belgium
| | - Lieven De Veylder
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
| | - Klaas Vandepoele
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
- Bioinformatics Institute Ghent, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
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8
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Pi S, Ma F, Cui D, Feng L, Zhou L, Li A. Catalytic reduction of 4-nitrophenol by green silver nanocomposites assembled using microbial extracellular polymer substances. ENVIRONMENTAL RESEARCH 2021; 197:111006. [PMID: 33722525 DOI: 10.1016/j.envres.2021.111006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/26/2021] [Accepted: 03/06/2021] [Indexed: 06/12/2023]
Abstract
Silver (Ag) nanocomposites were prepared via a facile and eco-friendly route using microbial extracellular polymer substances (EPSs) as green substrates for the catalytic reduction of 4-nitrophenol. Batch adsorption experiments demonstrated the binding of microbial EPSs to silver ions (Ag+), which was promoted by UV light, as was evident in the kinetics and thermodynamics analyses. The assembly mechanism of Ag nanocomposites prepared using microbial EPSs in the presence of UV light was investigated using the spectral analysis. The results showed that Ag+ was reduced and transformed into Ag0 by the hemiacetal groups in the microbial EPSs, and that UV light accelerated the nucleation and growth of Ag0 to form Ag nanoparticles (diameter about 12 nm), followed by loading on the surface of microbial EPSs. Catalytic reduction of 4-nitrophenol over Ag nanocomposites was almost completed within 60 s without stirring, and the kinetic rate constant (k) was 49.9 × 10-3 s-1. The recyclability test showed that Ag nanocomposites stably maintained the efficiency of catalytic reduction through five repeated reaction cycles. This work proved that Ag nanocomposites assembled using microbial EPSs have great catalytic activity in the reduction of 4-nitrophenol, providing the green and efficient catalyst for the reduction of organic pollutants in the environment.
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Affiliation(s)
- Shanshan Pi
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Fang Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Di Cui
- Pharmaceutical Engineering Technology Research Center, Harbin University of Commerce, Harbin, 150076, PR China
| | - Liang Feng
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Lu Zhou
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Ang Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
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9
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Zhang M, Xing Y, Wang F, Mi T, Zhen Y. Responses of triacylglycerol synthesis in Skeletonema marinoi to nitrogen and phosphate starvations. JOURNAL OF PHYCOLOGY 2020; 56:1505-1520. [PMID: 32602937 DOI: 10.1111/jpy.13044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/09/2020] [Indexed: 06/11/2023]
Abstract
Skeletonema marinoi is one of the most widespread marine planktonic diatoms in temperate coastal regions and sometimes can form massive blooms. Yet, the molecular mechanisms of triacylglycerol (TAG) synthesis in nutrient-deficient conditions for this species are still unknown. This study aimed to investigate how the TAG biosynthetic pathway of S. marinoi reacts to the culture age and nitrogen (N) or phosphorus (P) deficiency at molecular levels. Meanwhile, we also described the physiological and biochemical changes of S. marinoi in response to N or P starvation over time. To obtain reliable qRT-PCR data, six putative reference genes were identified for assessing expression stability using geNorm and BestKeeper software, and Actin exhibited the most stable expression across 45 tested S. marinoi samples. We found that the expression of TAG biosynthesis-related genes and ACCase enzyme activity varied in response to the different nutrient conditions and culture age. Taken together, we speculated that the capacity of TAG biosynthesis in S. marinoi is induced by N or P stress, and increases with culture age. Furthermore, TAG biosynthesis appears to respond more strongly to P deficiency than to N deficiency. Our study provides important insights into how diatoms regulate the TAG biosynthetic pathway when stressed by nutrient limitation. Besides, the data obtained from this study also provide useful clues for further exploring genes that can be used for metabolic engineering to enhance lipid production.
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Affiliation(s)
- Mei Zhang
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, 266100, China
| | - Yongze Xing
- Fourth Institute of Oceanography, Ministry of Natural Resources, Beihai, 536002, China
| | - Fuwen Wang
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, 266100, China
| | - Tiezhu Mi
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, 266100, China
| | - Yu Zhen
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, 266100, China
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Tisserand L, Dadaglio L, Intertaglia L, Catala P, Panagiotopoulos C, Obernosterer I, Joux F. Use of organic exudates from two polar diatoms by bacterial isolates from the Arctic Ocean. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190356. [PMID: 32862822 PMCID: PMC7481660 DOI: 10.1098/rsta.2019.0356] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Global warming affects primary producers in the Arctic, with potential consequences for the bacterial community composition through the consumption of microalgae-derived dissolved organic matter (DOM). To determine the degree of specificity in the use of an exudate by bacterial taxa, we used simple microalgae-bacteria model systems. We isolated 92 bacterial strains from the sea ice bottom and the water column in spring-summer in the Baffin Bay (Arctic Ocean). The isolates were grouped into 42 species belonging to Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. Forty strains were tested for their capacity to grow on the exudate from two Arctic diatoms. Most of the strains tested (78%) were able to grow on the exudate from the pelagic diatom Chaetoceros neogracilis, and 33% were able to use the exudate from the sea ice diatom Fragilariopsis cylindrus. 17.5% of the strains were not able to grow with any exudate, while 27.5% of the strains were able to use both types of exudates. All strains belonging to Flavobacteriia (n = 10) were able to use the DOM provided by C. neogracilis, and this exudate sustained a growth capacity of up to 100 times higher than diluted Marine Broth medium, of two Pseudomonas sp. strains and one Sulfitobacter strain. The variable bioavailability of exudates to bacterial strains highlights the potential role of microalgae in shaping the bacterial community composition. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.
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Affiliation(s)
- Lucas Tisserand
- Sorbonne Université, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, 66650 Banyuls/mer, France
| | - Laëtitia Dadaglio
- Sorbonne Université, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, 66650 Banyuls/mer, France
| | - Laurent Intertaglia
- Sorbonne Université, CNRS, FR3724, Observatoire Océanologique, 66650 Banyuls/Mer, France
| | - Philippe Catala
- Sorbonne Université, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, 66650 Banyuls/mer, France
| | | | - Ingrid Obernosterer
- Sorbonne Université, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, 66650 Banyuls/mer, France
| | - Fabien Joux
- Sorbonne Université, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, 66650 Banyuls/mer, France
- e-mail:
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11
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Young JN, Schmidt K. It's what's inside that matters: physiological adaptations of high-latitude marine microalgae to environmental change. THE NEW PHYTOLOGIST 2020; 227:1307-1318. [PMID: 32391569 DOI: 10.1111/nph.16648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 03/23/2020] [Indexed: 05/13/2023]
Abstract
Marine microalgae within seawater and sea ice fuel high-latitude ecosystems and drive biogeochemical cycles through the fixation and export of carbon, uptake of nutrients, and production and release of oxygen and organic compounds. High-latitude marine environments are characterized by cold temperatures, dark winters and a strong seasonal cycle. Within this environment a number of diverse and dynamic habitats exist, particularly in association with the formation and melt of sea ice, with distinct microalgal communities that transition with the season. Algal physiology is a crucial component, both responding to the dynamic environment and in turn influencing its immediate physicochemical environment. As high-latitude oceans shift into new climate regimes the analysis of seasonal responses may provide insights into how microalgae will respond to long-term environmental change. This review discusses recent developments in our understanding of how the physiology of high-latitude marine microalgae is regulated over a polar seasonal cycle, with a focus on ice-associated (sympagic) algae. In particular, physiologies that impact larger scale processes will be explored, with an aim to improve our understanding of current and future ecosystems and biogeochemical cycles.
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Affiliation(s)
- Jodi N Young
- School of Oceanography, University of Washington, Seattle, WA, 98195, USA
| | - Katrin Schmidt
- School of Oceanography, University of Washington, Seattle, WA, 98195, USA
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12
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Differences in the Formation Mechanism of Giant Colonies in Two Phaeocystis globosa Strains. Int J Mol Sci 2020; 21:ijms21155393. [PMID: 32751329 PMCID: PMC7432625 DOI: 10.3390/ijms21155393] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 07/14/2020] [Accepted: 07/27/2020] [Indexed: 12/27/2022] Open
Abstract
Phaeocystis globosa has become one of the primary causes of harmful algal bloom in coastal areas of southern China in recent years, and it poses a serious threat to the marine environment and other activities depending upon on it (e.g., aquaculture, cooling system of power plants), especially in the Beibu Gulf. We found colonies of P. globosa collected form Guangxi (China) were much larger than those obtained from Shantou cultured in lab. To better understand the causes of giant colonies formation, colonial cells collected from P. globosa GX strain (GX-C) and ST strain (ST-C) were separated by filtration. Morphological observations, phylogenetic analyses, rapid light-response curves, fatty acid profiling and transcriptome analyses of two type cells were performed in the laboratory. Although no differences in morphology and 18S rRNA sequences of these cells were observed, the colonies of GX strain (4.7 mm) are 30 times larger than those produced by the ST strain (300 μm). The rapid light-response curve of GX-C was greater than that of ST-C, consistent with the upregulated photosynthetic system, while the fatty acid content of GX-C was lower than that of ST-C, also consistent with the downregulated synthesis of fatty acids and the upregulated degradation of fatty acids. In summary, the increased energy generated by GX-C is allocated to promote the secretion of extracellular polysaccharides for colony formation. We performed a physiological and molecular assessment of the differences between the GX-C and ST-C strains, providing insights into the mechanisms of giant colonies formation in P. globosa.
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13
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Hoffmann L, Eggers SL, Allhusen E, Katlein C, Peeken I. Interactions between the ice algae Fragillariopsis cylindrus and microplastics in sea ice. ENVIRONMENT INTERNATIONAL 2020; 139:105697. [PMID: 32334123 DOI: 10.1016/j.envint.2020.105697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 03/23/2020] [Accepted: 03/26/2020] [Indexed: 06/11/2023]
Abstract
High concentrations of microplastics have been found in sea ice but the mechanisms by which they get captured into the ice and which role ice algae might play in this process remain unknown. Similarly, we do not know how the presence of microplastics might impact the colonization of sea ice by ice algae. To estimate the ecological impact of microplastics for Polar ecosystems, it is essential to understand their behaviour during ice formation and possible interactions with organisms inhabiting sea ice. In this study we tested the interaction between the ice algae Fragillariopsis cylindrus and microplastic beads with and without sea ice present and, in a third experiment, during the process of ice formation. With sea ice present, we found significantly less algae cells in the ice when incubated together with microplastics compared to the incubation without microplastics. However, during ice formation, the presence of microplastics did not impact the colonisation of the ice by F. cylindrus cells. Further, we observed a strong correlation between salinity and the relative amount of beads in the water and ice. With increasing salinity of the water, the relative amount of beads in the water decreased significantly. At the same time, the relative amount of beads in the ice increased significantly with increasing ice salinity. Both processes were not influenced by the presence of F. cylindrus. Also, we found indications that the presence of algae can affect the amount of microplastic beads sticking to the container walls. This could indicate that EPS produced by ice algae plays a significant role in surface binding properties of microplastics. Overall, our results highlight that the interactions between algae and microplastics have an influence on the uptake of microplastics into sea ice with possible implications for the sea ice food web.
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Affiliation(s)
- Linn Hoffmann
- University of Otago, Department of Botany, New Zealand.
| | - Sarah Lena Eggers
- Alfred-Wegener Institute Helmholtz Zentrum für Polar und Meeresforschung, Germany
| | - Erika Allhusen
- Alfred-Wegener Institute Helmholtz Zentrum für Polar und Meeresforschung, Germany
| | - Christian Katlein
- Alfred-Wegener Institute Helmholtz Zentrum für Polar und Meeresforschung, Germany
| | - Ilka Peeken
- Alfred-Wegener Institute Helmholtz Zentrum für Polar und Meeresforschung, Germany
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14
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Kamyab E, Goebeler N, Kellermann MY, Rohde S, Reverter M, Striebel M, Schupp PJ. Anti-Fouling Effects of Saponin-Containing Crude Extracts from Tropical Indo-Pacific Sea Cucumbers. Mar Drugs 2020; 18:E181. [PMID: 32244281 PMCID: PMC7231054 DOI: 10.3390/md18040181] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 12/21/2022] Open
Abstract
Sea cucumbers are bottom dwelling invertebrates, which are mostly found on subtropical and tropical sea grass beds, sandy reef flats, or reef slopes. Although constantly exposed to fouling communities in these habitats, many species are surprisingly free of invertebrate epibionts and microfouling algae such as diatoms. In our study, we investigated the anti-fouling (AF) activities of different crude extracts of tropical Indo-Pacific sea cucumber species against the fouling diatom Cylindrotheca closterium. Nine sea cucumber species from three genera (i.e., Holothuria, Bohadschia, Actinopyga) were selected and extracted to assess their AF activities. To verify whether the sea cucumber characteristic triterpene glycosides were responsible for the observed potent AF activities, we tested purified fractions enriched in saponins isolated from Bohadschia argus, representing one of the most active anti-fouling extracts. Saponins were quantified by vanillin-sulfuric acid colorimetric assays and identified by LC-MS and LC-MS/MS analyses. We were able to demonstrate that AF activities in sea cucumber extracts were species-specific, and growth inhibition as well as attachment of the diatom to surfaces is dependent on the saponin concentration (i.e., Actinopyga contained the highest quantities), as well as on the molecular composition and structure of the present saponins (i.e., Bivittoside D derivative was the most bioactive compound). In conclusion, the here performed AF assay represents a promising and fast method for selecting the most promising bioactive organism as well as for identifying novel compounds with potent AF activities for the discovery of potentially novel pharmacologically active natural products.
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Affiliation(s)
- Elham Kamyab
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany; (N.G.); (M.Y.K.); (S.R.); (M.R.); (M.S.)
| | - Norman Goebeler
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany; (N.G.); (M.Y.K.); (S.R.); (M.R.); (M.S.)
- Tvärminne Zoological Station, University of Helsinki, J.A. Palmènin tie 260, 10900 Hanko, Finland
| | - Matthias Y. Kellermann
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany; (N.G.); (M.Y.K.); (S.R.); (M.R.); (M.S.)
| | - Sven Rohde
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany; (N.G.); (M.Y.K.); (S.R.); (M.R.); (M.S.)
| | - Miriam Reverter
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany; (N.G.); (M.Y.K.); (S.R.); (M.R.); (M.S.)
| | - Maren Striebel
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany; (N.G.); (M.Y.K.); (S.R.); (M.R.); (M.S.)
| | - Peter J. Schupp
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany; (N.G.); (M.Y.K.); (S.R.); (M.R.); (M.S.)
- Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstrasse 231, D-26129 Oldenburg, Germany
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15
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Response of dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) cell quotas to salinity and temperature shifts in the sea-ice diatom Fragilariopsis cylindrus. Polar Biol 2020. [DOI: 10.1007/s00300-020-02651-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Zhang W, Tang X, Yang Y, Zhang X, Zhang X. Elevated pCO 2 Level Affects the Extracellular Polymer Metabolism of Phaeodactylum tricornutum. Front Microbiol 2020; 11:339. [PMID: 32194534 PMCID: PMC7064563 DOI: 10.3389/fmicb.2020.00339] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/17/2020] [Indexed: 01/08/2023] Open
Abstract
Extracellular polymeric substances (EPS) play an important role in diatom physiology and carbon biogeochemical cycling in marine ecosystems. Both the composition and yield of EPS in diatom cells can vary with environmental changes. However, information on intracellular pathways and controls of both biochemical and genetic of EPS is limited. Further, how such changes would affect their critical ecological roles in marine systems is also unclear. Here, we evaluated the physiological characteristics, EPS yields, EPS compositions, and gene expression levels of Phaeodactylum tricornutum under elevated pCO2 levels. Genes and pathways related to EPS metabolism in P. tricornutum were identified. Carbohydrate yields in different EPS fractions increased with elevated pCO2 exposure. Although the proportions of monosaccharide sugars among total sugars did not change, higher abundances of uronic acid were observed under high pCO2 conditions, suggesting the alterations of EPS composition. Elevated pCO2 increased PSII light energy conversion efficiency and carbon sequestration efficiency. The up-regulation of most genes involved in carbon fixation pathways led to increased growth and EPS release. RNA-Seq analysis revealed a number of genes and divergent alleles related to EPS production that were up-regulated by elevated pCO2 levels. Nucleotide diphosphate (NDP)-sugar activation and accelerated glycosylation could be responsible for more EPS responding to environmental signals. Further, NDP-sugar transporters exhibited increased expression levels, suggesting roles in EPS over-production. Overall, these results provide critical data for understanding the mechanisms of EPS production in diatoms and evaluating the metabolic plasticity of these organisms in response to environmental changes.
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Affiliation(s)
- Wei Zhang
- Department of Marine Ecology, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xuexi Tang
- Department of Marine Ecology, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory of Oceanology for Marine Science and Technology, Qingdao, China
| | - Yingying Yang
- Department of Marine Ecology, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xin Zhang
- Department of Marine Ecology, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xinxin Zhang
- Department of Marine Ecology, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory of Oceanology for Marine Science and Technology, Qingdao, China
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Metabolic activity analyses demonstrate that Lokiarchaeon exhibits homoacetogenesis in sulfidic marine sediments. Nat Microbiol 2019; 5:248-255. [PMID: 31873205 DOI: 10.1038/s41564-019-0630-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/04/2019] [Indexed: 01/09/2023]
Abstract
The genomes of the Asgard superphylum of Archaea hold clues pertaining to the nature of the host cell that acquired the mitochondrion at the origin of eukaryotes1-4. Representatives of the Asgard candidate phylum Candidatus Lokiarchaeota (Lokiarchaeon) have the capacity for acetogenesis and fermentation5-7, but how their metabolic activity responds to environmental conditions is poorly understood. Here, we show that in anoxic Namibian shelf sediments, Lokiarchaeon gene expression levels are higher than those of bacterial phyla and increase with depth below the seafloor. Lokiarchaeon gene expression was significantly different across a hypoxic-sulfidic redox gradient, whereby genes involved in growth, fermentation and H2-dependent carbon fixation had the highest expression under the most reducing (sulfidic) conditions. Quantitative stable isotope probing revealed that anaerobic utilization of CO2 and diatomaceous extracellular polymeric substances by Lokiarchaeon was higher than the bacterial average, consistent with higher expression of Lokiarchaeon genes, including those involved in transport and fermentation of sugars and amino acids. The quantitative stable isotope probing and gene expression data demonstrate homoacetogenic activity of Candidatus Lokiarchaeota, whereby fermentative H2 production from organic substrates is coupled with the Wood-Ljungdahl carbon fixation pathway8. The high energetic efficiency provided by homoacetogenesis8 helps to explain the elevated metabolic activity of Lokiarchaeon in this anoxic, energy-limited setting.
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18
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Ai C, Yan Z, Zhou H, Hou S, Chai L, Qiu G, Zeng W. Metagenomic Insights into the Effects of Seasonal Temperature Variation on the Activities of Activated Sludge. Microorganisms 2019; 7:E713. [PMID: 31861224 PMCID: PMC6956059 DOI: 10.3390/microorganisms7120713] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 12/13/2019] [Accepted: 12/13/2019] [Indexed: 01/09/2023] Open
Abstract
It is well acknowledged that the activities of activated sludge (AS) are influenced by seasonal temperature variation. However, the underlying mechanisms remain largely unknown. Here, the activities of activated sludge under three simulated temperature variation trends were compared in lab-scale. The TN, HN3-H, and COD removal activities of activated sludge were improved as temperature elevated from 20 °C to 35 °C. While, the TN, HN3-H, COD and total phosphorus removal activities of activated sludge were inhibited as temperature declined from 20 °C to 5 °C. Both the extracellular polymer substances (EPS) composition (e.g., total amount, PS, PN and DNA) and sludge index of activated sludge were altered by simulated seasonal temperature variation. The variation of microbial community structures and the functional potentials of activated sludge were further explored by metagenomics. Proteobacteria, Actinobacteria, Acidobacteria and Bacteroidetes were the dominant phyla for each activated sludge sample under different temperatures. However, the predominant genera of activated sludge were significantly modulated by simulated temperature variation. The functional genes encoding enzymes for nitrogen metabolism in microorganisms were analyzed. The enzyme genes related to ammonification had the highest abundance despite the changing temperature, especially for gene encoding glutamine synthetase. With the temperature raising from 20 °C to 35 °C. The abundance of amoCAB genes encoding ammonia monooxygenase (EC:1.14.99.39) increased by 305.8%. Meanwhile, all the enzyme genes associate with denitrification were reduced. As the temperature declined from 20 °C to 5 °C, the abundance of enzyme genes related to nitrogen metabolism were raised except for carbamate kinase (EC:2.7.2.2), glutamate dehydrogenase (EC:1.4.1.3), glutamine synthetase (EC:6.3.1.2). Metagenomic data indicate that succession of the dominant genera in microbial community structure is, to some extent, beneficial to maintain the functional stability of activated sludge under the temperature variation within a certain temperature range. This study provides novel insights into the effects of seasonal temperature variation on the activities of activated sludge.
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Affiliation(s)
- Chenbing Ai
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; (C.A.)
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Central South University, Changsha 410083, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Zhang Yan
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
- College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, China
| | - Han Zhou
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Shanshan Hou
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Liyuan Chai
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; (C.A.)
- Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Central South University, Changsha 410083, China
| | - Guanzhou Qiu
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Weimin Zeng
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
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Prelle LR, Graiff A, Gründling-Pfaff S, Sommer V, Kuriyama K, Karsten U. Photosynthesis and Respiration of Baltic Sea Benthic Diatoms to Changing Environmental Conditions and Growth Responses of Selected Species as Affected by an Adjacent Peatland (Hütelmoor). Front Microbiol 2019; 10:1500. [PMID: 31333612 PMCID: PMC6620715 DOI: 10.3389/fmicb.2019.01500] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 06/14/2019] [Indexed: 12/30/2022] Open
Abstract
Eight benthic diatom taxa (Actinocyclus octonarius, Melosira moniliformis, Halamphora sp. 1, Halamphora sp. 2, Navicula perminuta, Navicula phyllepta, Nitzschia dubiiformis, Nitzschia pusilla) were isolated from sediments sampled in the southern coastal brackish Baltic Sea and established as unialgal cultures. The coastal shallow water sampling area lies close to a fen peat site (Hütelmoor) and both are connected through an underground peat layer, which might facilitate organic matter and nutrient fluxes along the terrestrial-marine gradient. The photosynthetic performance of these diatoms was measured at different photon fluence rates (0-1200 μmol photons m-2 s-1, always recorded at 20°C) and different temperatures (5-40°C, always measured at saturating ∼270 μmol photons m-2 s-1), resulting in light saturation points between 32 and 151 μmol photons m-2 s-1 and maximum net primary production rates of 23-144 μmol O2 mg-1 Chl a h-1. None of the species showed severe photoinhibition, and hence all displayed a high photo-physiological plasticity. Photosynthetic oxygen evolution and respirational oxygen consumption between 5 and 40°C revealed eurythermal traits for half of the studied taxa as photosynthetic efficiency was at least 20% of the maximum values at the extreme temperatures. The remaining taxa also indicated eurythermal characteristics, however, photosynthetic efficiency of at least 20% was at a narrower temperature range [5 (10) °C to 30 (35) °C]. Species-specific optimum temperatures for photosynthesis (15-30°C) were always lower compared to respiration (25-40°C). Actinocyclus octonarius and Nitzschia dubiiformis were grown in different defined media, some enriched with Hütelmoor water to test for possible effects of organic components. Hütelmoor water media stimulated growth of both diatom species when kept in a light dark cycle. Actinocyclus octonarius particularly grew in darkness in Hütelmoor water media, pointing to heterotrophic capabilities. The benthic diatoms studied are characterized by high photo-physiological plasticity and a broad temperature tolerance to maintain high primary production rates under wide environmental fluctuations. Organic carbon fluxes from the Hütelmoor into the Baltic Sea may support mixo- and/or heterotrophic growth of microphytobenthic communities. These are essential traits for living in a highly dynamic and variable shallow water environment at the coastal zone of the Baltic Sea.
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Affiliation(s)
| | | | | | | | | | - Ulf Karsten
- Institute of Biological Sciences, Applied Ecology and Phycology, University of Rostock, Rostock, Germany
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20
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Abstract
In the Arctic Ocean ice algae constitute a key ecosystem component and the ice algal spring bloom a critical event in the annual production cycle. The bulk of ice algal biomass is usually found in the bottom few cm of the sea ice and dominated by pennate diatoms attached to the ice matrix. Here we report a red tide of the phototrophic ciliate Mesodinium rubrum located at the ice-water interface of newly formed pack ice of the high Arctic in early spring. These planktonic ciliates are not able to attach to the ice. Based on observations and theory of fluid dynamics, we propose that convection caused by brine rejection in growing sea ice enabled M. rubrum to bloom at the ice-water interface despite the relative flow between water and ice. We argue that red tides of M. rubrum are more likely to occur under the thinning Arctic sea ice regime.
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