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Zhu J, Yu Z, He L, Yuan Y, Wang W, Cao X, Chen N, Wang W, Song X. Mechanisms of Phaeocystis globosa blooms in the Beibu Gulf revealed by metatranscriptome analysis. HARMFUL ALGAE 2023; 124:102407. [PMID: 37164562 DOI: 10.1016/j.hal.2023.102407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/23/2023] [Accepted: 02/17/2023] [Indexed: 05/12/2023]
Abstract
The haptophyceae Phaeocystis globosa is a species responsible for harmful algal blooms in the global ocean, forming blooms in the Beibu Gulf annually since 2011. This species can alternate between solitary free-living cells and colonies. Colonies are the dominant morphotype during blooms. To date, the underlying mechanism of P. globosa blooms in the Beibu Gulf is poorly understood. After combining results of ecological surveys, laboratory studies, and metatranscriptome and bioinformatics analyses, it was found that low temperatures, high nitrate, and low organic phosphorus induced P. globosa blooms in the Beibu Gulf. Additionally, the unique genetic and physiological characteristics that allow P. globosa to stand out as a dominant species in such an environment include (1) several genes encoding high-affinity nitrate transport proteins that could be highly expressed under sufficient nitrate conditions; (2) energy metabolism genes involved in photosynthesis and oxidative phosphorylation that were actively expressed at low temperatures to carry out carbon and energy reversion and produce sufficient ATP for various life activities, individually; (3) abundant glycan synthesis genes that were highly expressed at low temperatures, thus synthesizing large quantities of proteoglycans to construct the mucilaginous envelope forming the colony; (4) cells in colonies exhibited active gene expression in DNA replication contributing to a faster growth rate, which could help P. globosa occupy niches quickly; and (5) the energy and material expenditure was redistributed in colonial cells accompanied with chitin filaments and flagella degraded, more expenditure was used for the synthesis of the mucilaginous envelope and the rapid proliferation.
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Affiliation(s)
- Jianan Zhu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China; Centre 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 of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China; Centre for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Liyan He
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China; Centre for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Yongquan Yuan
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China; Centre 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 of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China; Centre 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 of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China; Centre for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Nansheng Chen
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China; Centre for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Wei Wang
- Nuclear and Radiation Safety Center of MEE, Beijing 100082, China
| | - Xiuxian Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao 266237, China; Centre for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Cheng HM, Zhang SF, Ning XL, Peng JX, Li DX, Zhang H, Zhang K, Lin L, Liu SQ, Smith WO, Wang DZ. Elucidating colony bloom formation mechanism of a harmful alga Phaeocystis globosa (Prymnesiophyceae) using metaproteomics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161846. [PMID: 36709898 DOI: 10.1016/j.scitotenv.2023.161846] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/20/2023] [Accepted: 01/22/2023] [Indexed: 06/18/2023]
Abstract
Phaeocystis is a globally distributed Prymnesiophyte genus and usually forms massive harmful colony blooms, which impact marine ecosystem, mariculture, human health, and even threaten coastal nuclear power plant safety. However, the mechanisms behind the colony formation from the solitary cells remain poorly understood. Here, we investigated metabolic processes of both solitary and non-flagellated colonial cells of Phaeocystis globosa at different colony bloom stages in the subtropical Beibu Gulf using a metaproteomic approach. Temperature was significantly correlated with Phaeocystis colony bloom formation, and the flagellated motile solitary cells with abundant flagellum-associated proteins, such as tubulin and dynein, were the exclusive cellular morphotype at the solitary cell stage featured with temperatures ≥21 °C. When the temperature decreased to <21 °C, tiny colonies appeared and the flagellum-associated proteins were down-regulated in both solitary and non-flagellated colonial cells, while proteins involved in biosynthesis, chain polymerization and aggregation of glycosaminoglycan (GAG), a key constituent of gelatinous matrix, were up-regulated, indicating the central role of active GAG biosynthesis during the colony formation. Furthermore, light utilization, carbon fixation, nitrogen assimilation, and amino acid and protein synthesis were also enhanced to provide sufficient energy and substrates for GAG biosynthesis. This study highlighted that temperature induced re-allocation of energy and substances toward GAG biosynthesis is essential for colony bloom formation of P. globosa.
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Affiliation(s)
- Hua-Min Cheng
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China
| | - Shu-Feng Zhang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China
| | - Xiao-Lian Ning
- BGI-Shenzhen, Beishan Industrial Zone 11th Building, Yantian District, Shenzhen, Guangdong 518083, China
| | - Jian-Xiang Peng
- BGI-Shenzhen, Beishan Industrial Zone 11th Building, Yantian District, Shenzhen, Guangdong 518083, China
| | - Dong-Xu Li
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China
| | - Hao Zhang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China
| | - Kun Zhang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China
| | - Lin Lin
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China
| | - Si-Qi Liu
- BGI-Shenzhen, Beishan Industrial Zone 11th Building, Yantian District, Shenzhen, Guangdong 518083, China
| | - Walker O Smith
- School of Oceanography, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200300, China
| | - Da-Zhi Wang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China; Key Laboratory of Marine Ecology & Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
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Chen H, Hu Y, Li P, Feng X, Jiang M, Sui Z. Single-cell transcriptome sequencing revealing the difference in photosynthesis and carbohydrate metabolism between epidermal cells and non-epidermal cells of Gracilariopsis lemaneiformis (Rhodophyta). FRONTIERS IN PLANT SCIENCE 2022; 13:968158. [PMID: 36466256 PMCID: PMC9714639 DOI: 10.3389/fpls.2022.968158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 10/18/2022] [Indexed: 06/17/2023]
Abstract
The allocation of photoassimilates is considered as a key factor for determining plant productivity. The difference in photosynthesis and carbohydrate metabolism between source and sink cells provide the driven force for photoassimilates' allocation. However, photosynthesis and carbohydrate metabolism of different cells and the carbon allocation between these cells have not been elucidated in Gracilariopsis lemaneiformis. In the present study, transcriptome analysis of epidermal cells (EC) and non-epidermal cells (NEC) of G. lemaneiformis under normal light conditions was carried out. There were 3436 differentially expressed genes (DEGs) identified, and most of these DEGs were related to photosynthesis and metabolism. Based on a comprehensive analysis both at physiological and transcriptional level, the activity of photosynthesis and carbohydrate metabolism of EC and NEC were revealed. Photosynthesis activity and the synthesis activity of many low molecular weight carbohydrates (floridoside, sucrose, and others) in EC were significantly higher than those in NEC. However, the main carbon sink, floridean starch and agar, had higher levels in NEC. Moreover, the DEGs related to transportation of photoassimilates were found in this study. These results suggested that photoassimilates of EC could be transported to NEC. This study will contribute to our understanding of the source and sink relationship between the cells in G. lemaneiformis.
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Zhang SF, Han BB, Shi RJ, Wu FX, Rao YY, Dai M, Huang HH. Quantitative Proteomic Analysis Reveals the Key Molecular Events Driving Phaeocystis globosa Bloom and Dissipation. Int J Mol Sci 2022; 23:ijms232012668. [PMID: 36293526 PMCID: PMC9604223 DOI: 10.3390/ijms232012668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/06/2022] [Accepted: 10/19/2022] [Indexed: 11/16/2022] Open
Abstract
Phaeocystis globosa is a marine-bloom-forming haptophyte with a polymorphic life cycle alternating between free-living cells and a colonial morphotype, that produces high biomass and impacts ecological structure and function. The mechanisms of P. globosa bloom formation have been extensively studied, and various environmental factors are believed to trigger these events. However, little is known about the intrinsic biological processes that drive the bloom process, and the mechanisms underlying P. globosa bloom formation remain enigmatic. Here, we investigated a P. globosa bloom occurring along the Chinese coast and compared the proteomes of in situ P. globosa colonies from bloom and dissipation phases using a tandem mass tag (TMT)-based quantitative proteomic approach. Among the 5540 proteins identified, 191 and 109 proteins displayed higher abundances in the bloom and dissipation phases, respectively. The levels of proteins involved in photosynthesis, pigment metabolism, nitrogen metabolism, and matrix substrate biosynthesis were distinctly different between these two phases. Ambient nitrate is a key trigger of P. globosa bloom formation, while the enhanced light harvest and multiple inorganic carbon-concentrating mechanisms support the prosperousness of colonies in the bloom phase. Additionally, colonies in the bloom phase have greater carbon fixation potential, with more carbon and energy being fixed and flowing toward the colonial matrix biosynthesis. Our study revealed the key biological processes underlying P. globosa blooms and provides new insights into the mechanisms behind bloom formation.
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Affiliation(s)
- Shu-Fei Zhang
- Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Bei-Bei Han
- Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Rong-Jun Shi
- Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Feng-Xia Wu
- Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Yi-Yong Rao
- Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Ming Dai
- Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Hong-Hui Huang
- Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511485, China
- Correspondence:
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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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Marine Polymer-Gels' Relevance in the Atmosphere as Aerosols and CCN. Gels 2021; 7:gels7040185. [PMID: 34842644 PMCID: PMC8628772 DOI: 10.3390/gels7040185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 11/23/2022] Open
Abstract
Marine polymer gels play a critical role in regulating ocean basin scale biogeochemical dynamics. This brief review introduces the crucial role of marine gels as a source of aerosol particles and cloud condensation nuclei (CCN) in cloud formation processes, emphasizing Arctic marine microgels. We review the gel’s composition and relation to aerosols, their emergent properties, and physico-chemical processes that explain their change in size spectra, specifically in relation to aerosols and CCN. Understanding organic aerosols and CCN in this context provides clear benefits to quantifying the role of marine nanogel/microgel in microphysical processes leading to cloud formation. This review emphasizes the DOC-marine gel/aerosolized gel-cloud link, critical to developing accurate climate models.
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Marine Biopolymer Dynamics, Gel Formation, and Carbon Cycling in the Ocean. Gels 2021; 7:gels7030136. [PMID: 34563022 PMCID: PMC8482096 DOI: 10.3390/gels7030136] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/29/2021] [Accepted: 09/01/2021] [Indexed: 11/17/2022] Open
Abstract
Much like our own body, our planet is a macroscale dynamic system equipped with a complex set of compartmentalized controls that have made life and evolution possible on earth. Many of these global autoregulatory functions take place in the ocean; paramount among those is its role in global carbon cycling. Understanding the dynamics of organic carbon transport in the ocean remains among the most critical, urgent, and least acknowledged challenges to modern society. Dissolved in seawater is one of the earth's largest reservoirs of reduced organic carbon, reaching ~700 billion tons. It is composed of a polydisperse collection of marine biopolymers (MBP), that remain in reversible assembled↔dissolved equilibrium forming hydrated networks of marine gels (MG). MGs are among the least understood aspects of marine carbon dynamics. Despite the polymer nature of this gigantic pool of material, polymer physics theory has only recently been applied to study MBP dynamics and gel formation in the ocean. There is a great deal of descriptive phenomenology, rich in classifications, and significant correlations. Still missing, however, is the guide of robust physical theory to figure out the fundamental nature of the supramolecular interactions taking place in seawater that turn out to be critical to understanding carbon transport in the ocean.
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From Nano-Gels to Marine Snow: A Synthesis of Gel Formation Processes and Modeling Efforts Involved with Particle Flux in the Ocean. Gels 2021; 7:gels7030114. [PMID: 34449609 PMCID: PMC8395865 DOI: 10.3390/gels7030114] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 11/24/2022] Open
Abstract
Marine gels (nano-, micro-, macro-) and marine snow play important roles in regulating global and basin-scale ocean biogeochemical cycling. Exopolymeric substances (EPS) including transparent exopolymer particles (TEP) that form from nano-gel precursors are abundant materials in the ocean, accounting for an estimated 700 Gt of carbon in seawater. This supports local microbial communities that play a critical role in the cycling of carbon and other macro- and micro-elements in the ocean. Recent studies have furthered our understanding of the formation and properties of these materials, but the relationship between the microbial polymers released into the ocean and marine snow remains unclear. Recent studies suggest developing a (relatively) simple model that is tractable and related to the available data will enable us to step forward into new research by following marine snow formation under different conditions. In this review, we synthesize the chemical and physical processes. We emphasize where these connections may lead to a predictive, mechanistic understanding of the role of gels in marine snow formation and the biogeochemical functioning of the ocean.
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Marine Gel Interactions with Hydrophilic and Hydrophobic Pollutants. Gels 2021; 7:gels7030083. [PMID: 34287300 PMCID: PMC8293255 DOI: 10.3390/gels7030083] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/16/2021] [Accepted: 06/27/2021] [Indexed: 02/07/2023] Open
Abstract
Microgels play critical roles in a variety of processes in the ocean, including element cycling, particle interactions, microbial ecology, food web dynamics, air-sea exchange, and pollutant distribution and transport. Exopolymeric substances (EPS) from various marine microbes are one of the major sources for marine microgels. Due to their amphiphilic nature, many types of pollutants, especially hydrophobic ones, have been found to preferentially associate with marine microgels. The interactions between pollutants and microgels can significantly impact the transport, sedimentation, distribution, and the ultimate fate of these pollutants in the ocean. This review on marine gels focuses on the discussion of the interactions between gel-forming EPS and pollutants, such as oil and other hydrophobic pollutants, nanoparticles, and metal ions.
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Cytoklepty in the plankton: A host strategy to optimize the bioenergetic machinery of endosymbiotic algae. Proc Natl Acad Sci U S A 2021; 118:2025252118. [PMID: 34215695 DOI: 10.1073/pnas.2025252118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Endosymbioses have shaped the evolutionary trajectory of life and remain ecologically important. Investigating oceanic photosymbioses can illuminate how algal endosymbionts are energetically exploited by their heterotrophic hosts and inform on putative initial steps of plastid acquisition in eukaryotes. By combining three-dimensional subcellular imaging with photophysiology, carbon flux imaging, and transcriptomics, we show that cell division of endosymbionts (Phaeocystis) is blocked within hosts (Acantharia) and that their cellular architecture and bioenergetic machinery are radically altered. Transcriptional evidence indicates that a nutrient-independent mechanism prevents symbiont cell division and decouples nuclear and plastid division. As endosymbiont plastids proliferate, the volume of the photosynthetic machinery volume increases 100-fold in correlation with the expansion of a reticular mitochondrial network in close proximity to plastids. Photosynthetic efficiency tends to increase with cell size, and photon propagation modeling indicates that the networked mitochondrial architecture enhances light capture. This is accompanied by 150-fold higher carbon uptake and up-regulation of genes involved in photosynthesis and carbon fixation, which, in conjunction with a ca.15-fold size increase of pyrenoids demonstrates enhanced primary production in symbiosis. Mass spectrometry imaging revealed major carbon allocation to plastids and transfer to the host cell. As in most photosymbioses, microalgae are contained within a host phagosome (symbiosome), but here, the phagosome invaginates into enlarged microalgal cells, perhaps to optimize metabolic exchange. This observation adds evidence that the algal metamorphosis is irreversible. Hosts, therefore, trigger and benefit from major bioenergetic remodeling of symbiotic microalgae with potential consequences for the oceanic carbon cycle. Unlike other photosymbioses, this interaction represents a so-called cytoklepty, which is a putative initial step toward plastid acquisition.
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Chen CS, Shiu RF, Hsieh YY, Xu C, Vazquez CI, Cui Y, Hsu IC, Quigg A, Santschi PH, Chin WC. Stickiness of extracellular polymeric substances on different surfaces via magnetic tweezers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 757:143766. [PMID: 33243507 DOI: 10.1016/j.scitotenv.2020.143766] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/08/2020] [Accepted: 11/08/2020] [Indexed: 06/11/2023]
Abstract
Organic particle dynamics in the surface ocean plays a critical part in the marine carbon cycle. Aggregation of marine organic particles drives their downward transport to support various marine organisms on their transit to the sediments. Extracellular polymeric substances (EPS) from various microbes are a major contributor to the oceanic organic particle pool. The stickiness of EPS is expected to play a determining role in the aggregation process of particles; however, stickiness parameters are usually indirectly estimated through data fitting without direct assessment. Here a magnetic tweezer method was developed to quantitatively assess the stickiness of three model EPS produced by: Amphora sp., (diatom), Emiliania huxleyi (coccolithophore), and Sagittula stellata (bacteria), under different in vitro environmental conditions (salinity or EDTA complexed cations) and surface matrices (EPS-EPS and bare glass). Our results showed the stickiness of three microbial EPS decreasing for S. stellata > E. huxleyi > Amphora sp., in line with their decreasing protein-to-carbohydrate (P/C) ratios (related to their relative hydrophobicity). The data not only emphasize the importance of hydrophobicity on EPS stickiness, but also demonstrates that salinity and the nature of the substrate surface can influence the stickiness. Furthermore, we investigated stickiness between various types of EPS, and the observed selective stickiness of EPS between species may shed light on the interactions among heterogeneous marine microorganisms. Overall, this newly developed system provides a platform to assess the EPS stickiness to advance our understanding of the aggregation and sedimentation process of organic particles that are critical for the fate of organic carbon as well as for biofilm formation and microbial colonization of surfaces in the ocean.
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Affiliation(s)
- Chi-Shuo Chen
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ruei-Feng Shiu
- Institute of Marine Environment and Ecology, National Taiwan Ocean University, Keelung 20224, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 20224, Taiwan
| | - Yu-Ying Hsieh
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chen Xu
- Department of Marine and Coastal Environmental Science, Texas A&M University at Galveston, Galveston, TX 77553, USA
| | - Carlos I Vazquez
- Department of Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA
| | - Yujia Cui
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ian C Hsu
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Antonietta Quigg
- Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77553, USA; Department of Oceanography, Texas A&M University, College Station, TX 77843, USA
| | - Peter H Santschi
- Department of Marine and Coastal Environmental Science, Texas A&M University at Galveston, Galveston, TX 77553, USA; Department of Oceanography, Texas A&M University, College Station, TX 77843, USA
| | - Wei-Chun Chin
- Department of Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA.
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Shiu RF, Vazquez CI, Chiang CY, Chiu MH, Chen CS, Ni CW, Gong GC, Quigg A, Santschi PH, Chin WC. Nano- and microplastics trigger secretion of protein-rich extracellular polymeric substances from phytoplankton. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 748:141469. [PMID: 33113698 DOI: 10.1016/j.scitotenv.2020.141469] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/31/2020] [Accepted: 08/02/2020] [Indexed: 06/11/2023]
Abstract
The substantial increase in plastic pollution in marine ecosystems raises concerns about its adverse impacts on the microbial community. Microorganisms (bacteria, phytoplankton) are important producers of exopolymeric substances (EPS), which govern the processes of marine organic aggregate formation, microbial colonization, and pollutant mobility. Until now, the effects of nano- and micro-plastics on characteristics of EPS composition have received little attention. This study investigated EPS secretion by four phytoplankton species following exposure to various concentrations of polystyrene nano- and microplastics (55 nm nanoparticles; 1 and 6 μm microparticles). The 55 nm nanoparticles induced less growth/survival (determined on a DNA basis) and produced EPS with higher protein-to-carbohydrate (P/C) ratios than the exposure to microplastic particles. The amount of DNA from the four marine phytoplankton showed a higher negative linear correlation with increasing P/C ratios, especially in response to nanoplastic exposure. These results provide evidence that marine phytoplankton are quite sensitive to smaller-sized plastics and actively modify their EPS chemical composition to cope with the stress from pollution. Furthermore, the release of protein-rich EPS was found to facilitate aggregate formation and surface modification of plastic particles, thereby affecting their fate and colonization. Overall, this work offers new insights into the potential harm of different-sized plastic particles and a better understanding of the responding mechanism of marine phytoplankton for plastic pollution. The data also provide needed information about the fate of marine plastics and biogenic aggregation and scavenging processes.
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Affiliation(s)
- Ruei-Feng Shiu
- Institute of Marine Environment and Ecology, National Taiwan Ocean University, Keelung 20224, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 20224, Taiwan
| | - Carlos I Vazquez
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA
| | - Chang-Ying Chiang
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA
| | - Meng-Hsuen Chiu
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA; National Life Science, Inc., Sacramento, CA 95660, USA; Kaiser Biotech, Inc., Sacramento, CA 95660, USA
| | - Chi-Shuo Chen
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chih-Wen Ni
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA
| | - Gwo-Ching Gong
- Institute of Marine Environment and Ecology, National Taiwan Ocean University, Keelung 20224, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 20224, Taiwan
| | - Antonietta Quigg
- Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77553, USA; Department of Oceanography, Texas A&M University, College Station, TX 77843, USA
| | - Peter H Santschi
- Department of Oceanography, Texas A&M University, College Station, TX 77843, USA; Department of Marine and Coastal Environmental Science, Texas A&M University at Galveston, Galveston, TX 77553, USA
| | - Wei-Chun Chin
- Bioengineering, School of Engineering, University of California at Merced, Merced, CA 95343, USA.
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Zhang SF, Zhang K, Cheng HM, Lin L, Wang DZ. Comparative transcriptomics reveals colony formation mechanism of a harmful algal bloom species Phaeocystis globosa. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 719:137454. [PMID: 32114233 DOI: 10.1016/j.scitotenv.2020.137454] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/15/2020] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
Phaeocystis globosa is a major causative agent of harmful algal blooms in the global ocean, featuring a complex polymorphic life cycle alternating between free-living solitary cells and colonial cells. Colony is the dominant morphotype during P. globosa bloom. However, the underlying mechanism of colony formation is poorly understood. Here, we comprehensively compared global transcriptomes of P. globosa cells at four distinctive colony formation stages: free-living solitary cells, two cell-, four cell- and multi-cell colonies, under low (20 °C) and high (32 °C) temperatures, and characterized the genes involved in colony formation. Glycosaminoglycan (GAG) synthesis was enhanced while its degradation was decreased during colony formation, resulting in the accumulation of GAGs that are an essential substrate of the colony matrix. Nitrogen metabolism and glutamine synthesis were remarkably increased in the colonial cells, which provided precursors for GAG synthesis. Furthermore, cell defense and motility were down-regulated in the colonial cells, thereby conserving energy for GAG synthesis. Notably, high temperature led to decreased synthesis and increased degradation of GAGs, resulting in insufficient substrates to form the colony. Our study indicates that GAGs accumulation is critical for colony formation of P. globosa, but high temperature inhibits GAGs' accumulation and colony formation.
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Affiliation(s)
- Shu-Feng Zhang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
| | - Kun Zhang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
| | - Hua-Min Cheng
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
| | - Lin Lin
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
| | - Da-Zhi Wang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361102, China; Key Laboratory of Marine Ecology & Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
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14
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Mars Brisbin M, Mitarai S. Differential Gene Expression Supports a Resource-Intensive, Defensive Role for Colony Production in the Bloom-Forming Haptophyte, Phaeocystis globosa. J Eukaryot Microbiol 2019; 66:788-801. [PMID: 30860641 PMCID: PMC6766888 DOI: 10.1111/jeu.12727] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/23/2019] [Accepted: 02/28/2019] [Indexed: 12/22/2022]
Abstract
Phaeocystis globosa forms dense, monospecific blooms in temperate, northern waters. Blooms are usually dominated by the colonial morphotype—nonflagellated cells embedded in a secreted mucilaginous mass. Colonial Phaeocystis blooms significantly affect food‐web structure and function and negatively impact fisheries and aquaculture, but factors regulating colony formation remain enigmatic. Destructive P. globosa blooms have been reported in tropical and subtropical regions more recently and warm‐water blooms could become more common with continued climate change and coastal eutrophication. We therefore assessed genetic pathways associated with colony formation by investigating differential gene expression between colonial and solitary cells of a warm‐water P. globosa strain. Our results illustrate a transcriptional shift in colonial cells with most of the differentially expressed genes downregulated, supporting a reallocation of resources associated with forming and maintaining colonies. Dimethylsulfide and acrylate production and pathogen interaction pathways were upregulated in colonial cells, suggesting a defensive role for producing colonies. We identify several protein kinase signaling pathways that may influence the transition between morphotypes, providing targets for future research into factors affecting colony formation. This study provides novel insights into genetic mechanisms involved in Phaeocystis colony formation and provides new evidence supporting a defensive role for Phaeocystis colonies.
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Affiliation(s)
- Margaret Mars Brisbin
- Marine Biophysics Unit, Okinawa Institute of Science and Technology Graduate University, Onna-Son, Japan
| | - Satoshi Mitarai
- Marine Biophysics Unit, Okinawa Institute of Science and Technology Graduate University, Onna-Son, Japan
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15
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Mühlenbruch M, Grossart HP, Eigemann F, Voss M. Mini-review: Phytoplankton-derived polysaccharides in the marine environment and their interactions with heterotrophic bacteria. Environ Microbiol 2018; 20:2671-2685. [PMID: 30028074 DOI: 10.1111/1462-2920.14302] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 01/20/2023]
Abstract
Within the wealth of molecules constituting marine dissolved organic matter, carbohydrates make up the largest coherent and quantifiable fraction. Their main sources are from primary producers, which release large amounts of photosynthetic products - mainly polysaccharides - directly into the surrounding water via passive and active exudation. The organic carbon and other nutrients derived from these photosynthates enrich the 'phycosphere' and attract heterotrophic bacteria. The rapid uptake and remineralization of dissolved free monosaccharides by heterotrophic bacteria account for the barely detectable levels of these compounds. By contrast, dissolved combined polysaccharides can reach high concentrations, especially during phytoplankton blooms. Polysaccharides are too large to be taken up directly by heterotrophic bacteria, instead requiring hydrolytic cleavage to smaller oligo- or monomers by bacteria with a suitable set of exoenzymes. The release of diverse polysaccharides by various phytoplankton taxa is generally interpreted as the deposition of excess organic material. However, these molecules likely also fulfil distinct, yet not fully understood functions, as inferred from their active modulation in terms of quality and quantity when phytoplankton becomes nutrient limited or is exposed to heterotrophic bacteria. This minireview summarizes current knowledge regarding the exudation and composition of phytoplankton-derived exopolysaccharides and acquisition of these compounds by heterotrophic bacteria.
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Affiliation(s)
- Marco Mühlenbruch
- Leibniz-Institute for Baltic Sea Research Warnemünde, Rostock, Germany
| | - Hans-Peter Grossart
- Institute of Freshwater Ecology and Inland Fisheries, Neuglobsow, Germany.,Potsdam University, Institute of Biochemistry and Biology, Potsdam, Germany
| | - Falk Eigemann
- Leibniz-Institute for Baltic Sea Research Warnemünde, Rostock, Germany
| | - Maren Voss
- Leibniz-Institute for Baltic Sea Research Warnemünde, Rostock, Germany
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16
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Chiu MH, Khan ZA, Garcia SG, Le AD, Kagiri A, Ramos J, Tsai SM, Drobenaire HW, Santschi PH, Quigg A, Chin WC. Effect of Engineered Nanoparticles on Exopolymeric Substances Release from Marine Phytoplankton. NANOSCALE RESEARCH LETTERS 2017; 12:620. [PMID: 29236182 PMCID: PMC5729174 DOI: 10.1186/s11671-017-2397-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 11/30/2017] [Indexed: 05/30/2023]
Abstract
Engineered nanoparticles (ENPs), products from modern nanotechnologies, can potentially impact the marine environment to pose serious threats to marine ecosystems. However, the cellular responses of marine phytoplankton to ENPs are still not well established. Here, we investigate four different diatom species (Odontella mobiliensis, Skeletonema grethae, Phaeodactylum tricornutum, Thalassiosira pseudonana) and one green algae (Dunaliella tertiolecta) for their extracellular polymeric substances (EPS) release under model ENP treatments: 25 nm titanium dioxide (TiO2), 10-20 nm silicon dioxide (SiO2), and 15-30 nm cerium dioxide (CeO2). We found SiO2 ENPs can significantly stimulate EPS release from these algae (200-800%), while TiO2 ENP exposure induced the lowest release. Furthermore, the increase of intracellular Ca2+ concentration can be triggered by ENPs, suggesting that the EPS release process is mediated through Ca2+ signal pathways. With better understanding of the cellular mechanism mediated ENP-induced EPS release, potential preventative and safety measures can be developed to mitigate negative impact on the marine ecosystem.
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Affiliation(s)
- Meng-Hsuen Chiu
- Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA, 95343, USA
| | - Zafir A Khan
- Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA, 95343, USA
| | - Santiago G Garcia
- Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA, 95343, USA
| | - Andre D Le
- Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA, 95343, USA
| | - Agnes Kagiri
- Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA, 95343, USA
| | - Javier Ramos
- Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA, 95343, USA
| | - Shih-Ming Tsai
- Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA, 95343, USA
| | - Hunter W Drobenaire
- Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA, 95343, USA
| | - Peter H Santschi
- Department of Marine Science, Texas A&M University Galveston campus, Galveston, TX, USA
| | - Antonietta Quigg
- Department of Marine Biology, Texas A&M University Galveston campus, Galveston, TX, USA
| | - Wei-Chun Chin
- Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA, 95343, USA.
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17
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Thompson SEM, Coates JC. Surface sensing and stress-signalling in Ulva and fouling diatoms - potential targets for antifouling: a review. BIOFOULING 2017; 33:410-432. [PMID: 28508711 DOI: 10.1080/08927014.2017.1319473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 04/11/2017] [Indexed: 06/07/2023]
Abstract
Understanding the underlying signalling pathways that enable fouling algae to sense and respond to surfaces is essential in the design of environmentally friendly coatings. Both the green alga Ulva and diverse diatoms are important ecologically and economically as they are persistent biofoulers. Ulva spores exhibit rapid secretion, allowing them to adhere quickly and permanently to a ship, whilst diatoms secrete an abundance of extracellular polymeric substances (EPS), which are highly adaptable to different environmental conditions. There is evidence, now supported by molecular data, for complex calcium and nitric oxide (NO) signalling pathways in both Ulva and diatoms being involved in surface sensing and/or adhesion. Moreover, adaptation to stress has profound effects on the biofouling capability of both types of organism. Targets for future antifouling coatings based on surface sensing are discussed, with an emphasis on pursuing NO-releasing coatings as a potentially universal antifouling strategy.
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Affiliation(s)
| | - Juliet C Coates
- a School of Biosciences , University of Birmingham , Birmingham , UK
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18
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Thornton DCO, Chen J. Exopolymer production as a function of cell permeability and death in a diatom (Thalassiosira weissflogii) and a cyanobacterium (Synechococcus elongatus). JOURNAL OF PHYCOLOGY 2017; 53:245-260. [PMID: 27690180 DOI: 10.1111/jpy.12470] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/26/2016] [Indexed: 05/23/2023]
Abstract
Exopolymer particles are found throughout the ocean and play a significant biogeochemical role in carbon cycling. Transparent exopolymer particles (TEP) are composed of acid polysaccharides, and Coomassie staining particles (CSP) are proteins. TEPs have been extensively studied in the ocean, while CSP have been largely overlooked. The objective of this research was to determine the role of stress and cell permeability in the formation of TEP and CSP. The diatom Thalassiosira weissflogii and cyanobacterium Synechococcus elongatus were grown in batch cultures and exposed to hydrogen peroxide (0, 10, and 100 μM) as an environmental stressor. There was no correlation between TEP and CSP concentrations, indicating that they are different populations of particles rather than different chemical components of the same particles. CSP concentrations were not affected by hydrogen peroxide concentration and did not correlate with indicators of stress and cell death. In contrast, TEP concentrations in both taxa were correlated with a decrease in the effective quantum yield of photosystem II, increased activity of caspase-like enzymes, and an increase in the proportion of the population with permeable cell membranes, indicating that TEP production was associated with the process of cell death. These data show that different environmental factors and physiological processes affected the production of TEP and CSP by phytoplankton. TEP and CSP are separate populations of exopolymer particles with potentially different biogeochemical roles in the ocean.
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Affiliation(s)
- Daniel C O Thornton
- Department of Oceanography, Texas A & M University, College Station, Texas, 77843, USA
| | - Jie Chen
- Department of Oceanography, Texas A & M University, College Station, Texas, 77843, USA
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19
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Bar-Zeev E, Passow U, Castrillón SRV, Elimelech M. Transparent exopolymer particles: from aquatic environments and engineered systems to membrane biofouling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:691-707. [PMID: 25494664 DOI: 10.1021/es5041738] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Transparent exopolymer particles (TEP) are ubiquitous in marine and freshwater environments. For the past two decades, the distribution and ecological roles of these polysaccharide microgels in aquatic systems were extensively investigated. More recent studies have implicated TEP as an active agent in biofilm formation and membrane fouling. Since biofouling is one of the main hurdles for efficient operation of membrane-based technologies, there is a heightened interest in understanding the role of TEP in engineered water systems. In this review, we describe relevant TEP terminologies while critically discussing TEP biological origin, biochemical and physical characteristics, and occurrence and distributions in aquatic systems. Moreover, we examine the contribution of TEP to biofouling of various membrane technologies used in the desalination and water/wastewater treatment industry. Emphasis is given to the link between TEP physicochemical and biological properties and the underlying biofouling mechanisms. We highlight that thorough understanding of TEP dynamics in feedwater sources, pretreatment challenges, and biofouling mechanisms will lead to better management of fouling/biofouling in membrane technologies.
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20
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Moon TC, Befus AD, Kulka M. Mast cell mediators: their differential release and the secretory pathways involved. Front Immunol 2014; 5:569. [PMID: 25452755 PMCID: PMC4231949 DOI: 10.3389/fimmu.2014.00569] [Citation(s) in RCA: 273] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 10/23/2014] [Indexed: 12/14/2022] Open
Abstract
Mast cells (MC) are widely distributed throughout the body and are common at mucosal surfaces, a major host-environment interface. MC are functionally and phenotypically heterogeneous depending on the microenvironment in which they mature. Although MC have been classically viewed as effector cells of IgE-mediated allergic diseases, they are also recognized as important in host defense, innate and acquired immunity, homeostatic responses, and immunoregulation. MC activation can induce release of pre-formed mediators such as histamine from their granules, as well as release of de novo synthesized lipid mediators, cytokines, and chemokines that play diverse roles, not only in allergic reactions but also in numerous physiological and pathophysiological responses. Indeed, MC release their mediators in a discriminating and chronological manner, depending upon the stimuli involved and their signaling cascades (e.g., IgE-mediated or Toll-like receptor-mediated). However, the precise mechanisms underlying differential mediator release in response to these stimuli are poorly known. This review summarizes our knowledge of MC mediators and will focus on what is known about the discriminatory release of these mediators dependent upon diverse stimuli, MC phenotypes, and species of origin, as well as on the intracellular synthesis, storage, and secretory processes involved.
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Affiliation(s)
- Tae Chul Moon
- Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - A. Dean Befus
- Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Marianna Kulka
- National Institute for Nanotechnology, National Research Council, Edmonton, AB, Canada
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21
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Orellana MV, Pang WL, Durand PM, Whitehead K, Baliga NS. A role for programmed cell death in the microbial loop. PLoS One 2013; 8:e62595. [PMID: 23667496 PMCID: PMC3648572 DOI: 10.1371/journal.pone.0062595] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 03/25/2013] [Indexed: 12/03/2022] Open
Abstract
The microbial loop is the conventional model by which nutrients and minerals are recycled in aquatic eco-systems. Biochemical pathways in different organisms become metabolically inter-connected such that nutrients are utilized, processed, released and re-utilized by others. The result is that unrelated individuals end up impacting each others' fitness directly through their metabolic activities. This study focused on the impact of programmed cell death (PCD) on a population's growth as well as its role in the exchange of carbon between two naturally co-occurring halophilic organisms. Flow cytometric, biochemical, ¹⁴C radioisotope tracing assays, and global transcriptomic analyses show that organic algal photosynthate released by Dunalliela salina cells undergoing PCD complements the nutritional needs of other non-PCD D. salina cells. This occurs in vitro in a carbon limited environment and enhances the growth of the population. In addition, a co-occurring heterotroph Halobacterium salinarum re-mineralizes the carbon providing elemental nutrients for the mixoheterotrophic chlorophyte. The significance of this is uncertain and the archaeon can also subsist entirely on the lysate of apoptotic algae. PCD is now well established in unicellular organisms; however its ecological relevance has been difficult to decipher. In this study we found that PCD in D. salina causes the release of organic nutrients such as glycerol, which can be used by others in the population as well as a co-occurring halophilic archaeon. H. salinarum also re-mineralizes the dissolved material promoting algal growth. PCD in D. salina was the mechanism for the flow of dissolved photosynthate between unrelated organisms. Ironically, programmed death plays a central role in an organism's own population growth and in the exchange of nutrients in the microbial loop.
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Affiliation(s)
- Mónica V. Orellana
- Institute for Systems Biology, Seattle, Washington, United States of America
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, Washington, United States of America
| | - Wyming L. Pang
- Institute for Systems Biology, Seattle, Washington, United States of America
- Genomatica, Inc., San Diego, California, United States of America
| | - Pierre M. Durand
- Department of Molecular Medicine, University of the Witwatersrand and National Health Laboratory Service, Parktown, South Africa
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, United States of America
| | - Kenia Whitehead
- Institute for Systems Biology, Seattle, Washington, United States of America
- Integral Consulting Inc., Seattle, Washington, United States of America
| | - Nitin S. Baliga
- Institute for Systems Biology, Seattle, Washington, United States of America
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
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22
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Humby PL, Snyder ECR, Durnford DG. Conditional senescence in Chlamydomonas reinhardtii (Chlorophyceae). JOURNAL OF PHYCOLOGY 2013; 49:389-400. [PMID: 27008525 DOI: 10.1111/jpy.12049] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 01/05/2013] [Indexed: 06/05/2023]
Abstract
The mechanisms of microalgal senescence may play an important role in nutrient recycling and enhanced survival. However, the aging physiology of microalgae is an understudied phenomenon. To investigate the patterns of conditional senescence in Chlamydomonas reinhardtii P. A. Dangeard, we used a cell wall-less strain, transformed with a reporter gene to infer changes in photosynthetic gene expression. We examined plastid ultrastructure, photosynthetic function, and photoprotective mechanisms during aging in batch cultures. LHCII transcription levels decreased before the population entered stationary phase, and the characteristic transcriptional light-shift response was lost. A decline in photosynthetic proteins with a concomitant increase in the photoprotective protein, LHCSR, was observed over time. However, nonphotochemical quenching remained stable during growth and stationary phase, and then declined as alternative quenching mechanisms were up-regulated. Photosynthetic efficiency declined, while Fv/Fm remained stable until the death phases. As the culture progressed through stationary phase, disorganization of the chloroplast was observed along with an increase in cytoplasmic oil bodies. We also observed a partial recovery of function and proteins during the final death phase, and attribute this to the release of nutrients into the medium from cell lysis and/or active secretion while cells were senescing. Allowing open gas exchange resulted in high levels of sustained starch production and maintained maximum cell density, prolonging the stationary phase.
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Affiliation(s)
- Penny L Humby
- Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, New Brunswick, Canada, E3B 5A3
| | - Ellen C R Snyder
- Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, New Brunswick, Canada, E3B 5A3
| | - Dion G Durnford
- Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, New Brunswick, Canada, E3B 5A3
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23
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Sheik AR, Brussaard CPD, Lavik G, Foster RA, Musat N, Adam B, Kuypers MMM. Viral infection of Phaeocystis globosa impedes release of chitinous star-like structures: quantification using single cell approaches. Environ Microbiol 2012; 15:1441-51. [PMID: 22857133 DOI: 10.1111/j.1462-2920.2012.02838.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phaeocystis globosa is an ecologically important bloom-forming phytoplankton, which sequesters substantial amounts of inorganic carbon and can form carbon-enriched chitinous star-like structures. Viruses infecting P. globosa (PgVs) play a significant regulatory role in population dynamics of the host species. However, the extent to which viruses alter host physiology and its carbon assimilation on single cell level is still largely unknown. This study demonstrates for the first time the impact of viral infection on carbon assimilation and cell morphology of individual axenic P. globosa cells using two single cell techniques: high resolution nanometre-scale Secondary-Ion Mass Spectrometry (nanoSIMS) approach and atomic force microscopy (AFM). Up until viral lysis (19 h post infection), the bulk carbon assimilation by infected P. globosa cultures was identical to the assimilation by the non-infected cultures (33 µmol C l(-1)). However, single cell analysis showed that viral infection of P. globosa impedes the release of star-like structures. Non-infected cells transfer up to 44.5 µmol C l(-1) (36%) of cellular biomass in the form of star-like structures, suggesting a vital role in the survival of P. globosa cells. We hypothesize that impediment of star-like structures in infected P. globosa cells may inactivate viral infectivity by forming flocculants after cell lysis. Moreover, we show that substantial amounts of newly produced viruses (≈ 68%) were attached to P. globosa cells prior to cell lysis. Further, we speculate that infected cells become more susceptible for grazing which provides potential reasons for the sudden disappearance of PgVs in the environment. The scenarios of enhanced grazing is at odds to the current perspective that viral infections facilitates microbial mediated processes by diverting host material away from the higher trophic levels.
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Affiliation(s)
- A R Sheik
- Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Bremen, Germany.
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Yoo SH, Hur YS. Enrichment of the inositol 1,4,5-trisphosphate receptor/Ca2+ channels in secretory granules and essential roles of chromogranins. Cell Calcium 2012; 51:342-50. [DOI: 10.1016/j.ceca.2011.12.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/07/2011] [Accepted: 12/10/2011] [Indexed: 11/26/2022]
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Abstract
The ocean plays a critical role in global carbon cycling: it handles half of the global primary production, yielding the world's largest stock of reduced organic carbon (ROC) that supports one of the world's largest biomasses. However, the mechanisms whereby ROC becomes mineralized remain unresolved. This review focuses on laboratory and field observations that dissolved organic carbon (DOC) self-assembles, forming self-assembled microgels (SAGs). Self-assembly has approximately10% yield, generating an estimated global seawater SAG budget of approximately 10(16) g C. Transects at depths of 10-4,000 m reveal concentrations of approximately 10(6) to approximately 3 x 10(12) SAG L(-1), respectively, forming an estimated ROC stock larger than the global marine biomass. Because hydrogels have approximately 1% solids (10 g L(-1)), whereas seawater DOC reaches approximately 10(-3) g L(-1), SAGs contain approximately 10(4) more bacterial substrate than seawater. Thus, microgels represent an unsuspected and huge micron-level ocean patchiness that could profoundly influence the passage of DOC through the microbial loop, with ramifications that may scale to global cycles of bioactive elements.
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Affiliation(s)
- Pedro Verdugo
- Department of Bioengineering and Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington 98250, USA.
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Orellana MV, Matrai PA, Leck C, Rauschenberg CD, Lee AM, Coz E. Marine microgels as a source of cloud condensation nuclei in the high Arctic. Proc Natl Acad Sci U S A 2011; 108:13612-7. [PMID: 21825118 PMCID: PMC3158224 DOI: 10.1073/pnas.1102457108] [Citation(s) in RCA: 202] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Marine microgels play an important role in regulating ocean basin-scale biogeochemical dynamics. In this paper, we demonstrate that, in the high Arctic, marine gels with unique physicochemical characteristics originate in the organic material produced by ice algae and/or phytoplankton in the surface water. The polymers in this dissolved organic pool assembled faster and with higher microgel yields than at other latitudes. The reversible phase transitions shown by these Arctic marine gels, as a function of pH, dimethylsulfide, and dimethylsulfoniopropionate concentrations, stimulate the gels to attain sizes below 1 μm in diameter. These marine gels were identified with an antibody probe specific toward material from the surface waters, sized, and quantified in airborne aerosol, fog, and cloud water, strongly suggesting that they dominate the available cloud condensation nuclei number population in the high Arctic (north of 80°N) during the summer season. Knowledge about emergent properties of marine gels provides important new insights into the processes controlling cloud formation and radiative forcing, and links the biology at the ocean surface with cloud properties and climate over the central Arctic Ocean and, probably, all oceans.
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Affiliation(s)
| | | | - Caroline Leck
- Department of Meteorology, Stockholm University, SE-106 91 Stockholm, Sweden; and
| | | | | | - Esther Coz
- Department of Meteorology, Stockholm University, SE-106 91 Stockholm, Sweden; and
- CIEMAT, Department of Environment, E-28040 Madrid, Spain
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Orellana MV, Matrai PA, Janer M, Rauschenberg CD. DIMETHYLSULFONIOPROPIONATE STORAGE IN PHAEOCYSTIS (PRYMNESIOPHYCEAE) SECRETORY VESICLES(1). JOURNAL OF PHYCOLOGY 2011; 47:112-117. [PMID: 27021716 DOI: 10.1111/j.1529-8817.2010.00936.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Despite the global importance of dimethylsulfoniopropionate (DMSP)/dimethyl sulfide (DMS) and their role in climate regulation, little is known about the mechanisms of their production and storage in Phaeocystis sp., a major contributor of DMS in polar areas. Phaeocystis secretes polymer microgels, by regulated exocytosis, remaining in condensed phase while stored in secretory vesicles (Chin et al. 2004). In secretory cells, vesicles also store small molecules, which are released during exocytosis. Here, we demonstrated that DMSP and DMS were stored in the secretory vesicles of Phaeocystis antarctica G. Karst. They were trapped within a polyanionic gel matrix, which prevented an accurate measurement of their concentration in the absence of a chelating agent such as EDTA. Understanding the production and the export mechanisms of DMSP and DMS into seawater is important because of the impact the cellular and extracellular pools of these highly relevant biogeochemical metabolites have on the environment. The pool of total DMSP in the presence of Phaeocystis may be underestimated by as much as half. Obtaining accurate budget measurements is the first step toward gaining a better understanding of key issues related to the DMS ocean-air interaction and the effect of phytoplankton DMS production on climate change.
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Affiliation(s)
- Mónica V Orellana
- Institute for Systems Biology, Seattle, Washington 98103, USABigelow Laboratory for Ocean Sciences, W. Boothbay Harbor, Maine 04575, USAInstitute for Systems Biology, Seattle, Washington 98103, USABigelow Laboratory for Ocean Sciences, W. Boothbay Harbor, Maine 04575, USA
| | - Patricia A Matrai
- Institute for Systems Biology, Seattle, Washington 98103, USABigelow Laboratory for Ocean Sciences, W. Boothbay Harbor, Maine 04575, USAInstitute for Systems Biology, Seattle, Washington 98103, USABigelow Laboratory for Ocean Sciences, W. Boothbay Harbor, Maine 04575, USA
| | - Marta Janer
- Institute for Systems Biology, Seattle, Washington 98103, USABigelow Laboratory for Ocean Sciences, W. Boothbay Harbor, Maine 04575, USAInstitute for Systems Biology, Seattle, Washington 98103, USABigelow Laboratory for Ocean Sciences, W. Boothbay Harbor, Maine 04575, USA
| | - Carlton D Rauschenberg
- Institute for Systems Biology, Seattle, Washington 98103, USABigelow Laboratory for Ocean Sciences, W. Boothbay Harbor, Maine 04575, USAInstitute for Systems Biology, Seattle, Washington 98103, USABigelow Laboratory for Ocean Sciences, W. Boothbay Harbor, Maine 04575, USA
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28
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Yoo SH. Role of secretory granules in inositol 1,4,5-trisphosphate-dependent Ca(2+) signaling: from phytoplankton to mammals. Cell Calcium 2010; 50:175-83. [PMID: 21176957 DOI: 10.1016/j.ceca.2010.11.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/30/2010] [Accepted: 11/30/2010] [Indexed: 01/20/2023]
Abstract
The majority of secretory cell calcium is stored in secretory granules that serve as the major IP(3)-dependent intracellular Ca(2+) store. Even in unicellular phytoplankton secretory granules are responsible for the IP(3)-induced Ca(2+) release that triggers exocytosis. The number of secretory granules in the cell is directly related not only to the magnitude of IP(3)-induced Ca(2+) release, which accounts for the majority of the IP(3)-induced cytoplasmic Ca(2+) release in neuroendocrine cells, but also to the IP(3) sensitivity of the cytoplasmic IP(3) receptor (IP(3)R)/Ca(2+) channels. Moreover, secretory granules contain the highest IP(3)R concentrations and the largest amounts of IP(3)Rs in any subcellular organelles in neuroendocrine cells. Secretory granules from phytoplankton to mammals contain large amounts of polyanionic molecules, chromogranins being the major molecules in mammals, in addition to acidic intragranular pH and high Ca(2+) concentrations. The polyanionic molecules undergo pH- and Ca(2+)-dependent conformational changes that serve as a molecular basis for condensation-decondensation phase transitions of the intragranular matrix. Likewise, chromogranins undergo pH- and Ca(2+)-dependent conformational changes with increased exposure of the structure and increased interactions with Ca(2+) and other granule components at acidic pH. The unique physico-chemical properties of polyanionic molecules appear to be at the center of biogenesis, and physiological functions of secretory granules in living organisms from primitive to advanced species.
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Affiliation(s)
- Seung Hyun Yoo
- Department of Biochemistry, Inha University School of Medicine, Jung Gu, Incheon 400-712, Republic of Korea.
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29
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Verret F, Wheeler G, Taylor AR, Farnham G, Brownlee C. Calcium channels in photosynthetic eukaryotes: implications for evolution of calcium-based signalling. THE NEW PHYTOLOGIST 2010; 187:23-43. [PMID: 20456068 DOI: 10.1111/j.1469-8137.2010.03271.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Much of our current knowledge on the mechanisms by which Ca(2+) signals are generated in photosynthetic eukaryotes comes from studies of a relatively small number of model species, particularly green plants and algae, revealing some common features and notable differences between 'plant' and 'animal' systems. Physiological studies from a broad range of algal cell types have revealed the occurrence of animal-like signalling properties, including fast action potentials and fast propagating cytosolic Ca(2+) waves. Genomic studies are beginning to reveal the widespread occurrence of conserved channel types likely to be involved in Ca(2+) signalling. However, certain widespread 'ancient' channel types appear to have been lost by certain groups, such as the embryophytes. More recent channel gene loss is also evident from comparisons of more closely related algal species. The underlying processes that have given rise to the current distributions of Ca(2+) channel types include widespread retention of ancient Ca(2+) channel genes, horizontal gene transfer (including symbiotic gene transfer and acquisition of bacterial genes), gene loss and gene expansion within taxa. The assessment of the roles of Ca(2+) channel genes in diverse physiological, developmental and life history processes represents a major challenge for future studies.
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Affiliation(s)
- Frédéric Verret
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | - Glen Wheeler
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, UK
| | - Alison R Taylor
- Department of Biology and Marine Biology, University of North Carolina, 601 S. College Road, Wilmington, NC 28403, USA
| | - Garry Farnham
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, UK
| | - Colin Brownlee
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
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30
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Abstract
Despite the impressive advances that have been made in assessing the diversity of marine microorganisms, the mechanisms that underlie the participation of microorganisms in marine food webs and biogeochemical cycles are poorly understood. Here, we stress the need to examine the biochemical interactions of microorganisms with ocean systems at the nanometre to millimetre scale--a scale that is relevant to microbial activities. The local impact of microorganisms on biogeochemical cycles must then be scaled up to make useful predictions of how marine ecosystems in the whole ocean might respond to global change. This approach to microbial oceanography is not only helpful, but is in fact indispensable.
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Affiliation(s)
- Farooq Azam
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093, USA.
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Thompson SEM, Callow JA, Callow ME, Wheeler GL, Taylor AR, Brownlee C. Membrane recycling and calcium dynamics during settlement and adhesion of zoospores of the green alga Ulva linza. PLANT, CELL & ENVIRONMENT 2007; 30:733-44. [PMID: 17470149 DOI: 10.1111/j.1365-3040.2007.01661.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Recruitment of individuals of the marine alga Ulva linza on to a suitable habitat involves the settlement of motile zoospores on to a substratum during which a preformed adhesive is secreted by vesicular exocytosis. The fluorescent styryl dye FM 1-43 and fluorescent Ca(2+) indicators were used to follow membrane cycling and changes in cytosolic Ca(2+) ([Ca(2+)](cyt)) associated with settlement. When swimming zoospores were exposed continuously to FM 1-43, the plasma membrane was preferentially labelled. During settlement, FM 1-43-labelled plasma membrane was rapidly internalized reflecting high membrane turnover. The internalized membrane was focused into a discrete region indicating targeting of membrane to an endosome-like compartment. Acetoxymethyl (AM)-ester derivatives were found to be unsuitable for monitoring [Ca(2+)](cyt) because the dyes were rapidly sequestered from the cytoplasm into sub-cellular compartments. [Ca(2+)](cyt) was, however, reliably measured using dextran-conjugated calcium indicators delivered into cells using a biolistic technique. Cells loaded with Oregon Green BAPTA-1 dextran (Invitrogen, Paisley, UK) showed diffuse cytosolic loading and reliably responded to imposed changes in [Ca(2+)](cyt). During settlement, zoospores exhibited both localized and diffuse increases in [Ca(2+)](cyt) implying a role for [Ca(2+)](cyt) in exocytosis of the adhesive.
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Affiliation(s)
- S E M Thompson
- School of Biosciences, The University of Birmingham, Birmingham, and Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, UK
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32
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Abstract
Mucus secretions have played a central role in the evolution of multicellular organisms, enabling adaptation to widely differing environments. In vertebrates, mucus covers and protects the epithelial cells in the respiratory, gastrointestinal, urogenital, visual, and auditory systems, amphibian's epidermis, and the gills in fishes. Deregulation of mucus production and/or composition has important consequences for human health. For example, mucus obstruction of small airways is observed in chronic airway diseases, including chronic obstructive pulmonary disease, asthma, and cystic fibrosis. The major protein component in the mucus is a family of large, disulfide-bonded glycoproteins known as gel-forming mucins. These proteins are accumulated in large, regulated secretory granules (the mucin granules) that occupy most of the apical cytoplasm of specialized cells known as mucous/goblet cells. Since mucin oligomers have contour dimensions larger than the mucin granule average diameter, the question arises how these highly hydrophilic macromolecules are organized within these organelles. I review here the intraluminal organization of the mucin granule in view of our knowledge on the structure, biosynthesis, and biophysical properties of gel-forming mucins, and novel imaging studies in living mucous/goblet cells. The emerging concept is that the mucin granule lumen comprises a partially condensed matrix meshwork embedded in a fluid phase where proteins slowly diffuse.
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Affiliation(s)
- Juan Perez-Vilar
- Cystic Fibrosis/Pulmonary Research and Treatment Center, School of Medicine, University of North Carolina at Chapel Hill, NC 27599-7248, USA.
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33
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Quesada I, Chin WC, Verdugo P. Mechanisms of signal transduction in photo-stimulated secretion in Phaeocystis globosa. FEBS Lett 2006; 580:2201-6. [PMID: 16574108 DOI: 10.1016/j.febslet.2006.02.081] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Revised: 02/27/2006] [Accepted: 02/28/2006] [Indexed: 10/24/2022]
Abstract
Phaeocystis globosa, a leading agent in marine carbon cycling, releases its photosynthesized biopolymers via regulated exocytosis. Release is elicited by blue light and relayed by a characteristic cytosolic Ca(2+) signal. However, the source of Ca(2+) in these cells has not been established. The present studies indicate that Phaeocystis' secretory granules work as an intracellular Ca(2+) oscillator. Optical tomography reveals that photo-stimulation induces InsP(3)-triggered periodic lumenal [Ca(2+)] oscillations in the granule and corresponding out-of-phase cytosolic oscillations of [Ca(2+)] that trigger exocytosis. This Ca(2+) dynamics results from an interplay between the intragranular polyanionic matrix, and two Ca(2+)-sensitive ion channels located on the granule membrane: an InsP(3)-receptor-Ca(2+) channel, and an apamin-sensitive K(+) channel.
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Affiliation(s)
- Ivan Quesada
- Department of Bioengineering, University of Washington, Friday Harbor Laboratories, 620 University Road, Friday Harbor, Seattle, WA 98195, USA
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34
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Ferreyra GA, Mostajir B, Schloss IR, Chatila K, Ferrario ME, Sargian P, Roy S, Prod'homme J, Demers S. Ultraviolet-B Radiation Effects on the Structure and Function of Lower Trophic Levels of the Marine Planktonic Food Web. Photochem Photobiol 2006; 82:887-97. [PMID: 17205621 DOI: 10.1562/2006-02-23-ra-810] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The impact of UV-B radiation (UVBR; 280-320 nm) on lower levels of a natural plankton assemblage (bacteria, phytoplankton and microzooplankton) from the St. Lawrence Estuary was studied during 9 days using several immersed outdoor mesocosms. Two exposure treatments were used in triplicate mesocosms: natural UVBR (N treatment, considered as the control treatment) and lamp-enhanced UVBR (H treatment, simulating 60% depletion of the ozone layer). A phytoplankton bloom developed after day 3, but no significant differences were found between treatments during the entire experiment for phytoplankton biomass (chlorophyll a and cell carbon) nor for phytoplankton cell abundances from flow cytometry and optical microscopy of three phytoplankton size classes (picoplankton, nanoplankton and microplankton). In contrast, bacterial abundances showed significantly higher values in the H treatment, attributed to a decrease in predation pressure due to a dramatic reduction in ciliate biomass (approximately 70-80%) in the H treatment relative to the N treatment. The most abundant ciliate species were Strombidinium sp., Prorodon ovum and Tintinnopsis sp.; all showed significantly lower abundances under the H treatment. P. ovum was the less-affected species (50% reduction in the H treatment compared with that of the N control), contrasting with approximately 90% for the other ones. Total specific phytoplanktonic and bacterial production were not affected by enhanced UVBR. However, both the ratio of primary to bacterial biomass and production decreased markedly under the H treatment. In contrast, the ratio of phytoplankton to bacterial plus ciliate carbon biomass showed an opposite trend than the previous results, with higher values in the H treatment at the end of the experiment. These results are explained by the changes in the ciliate biomass and suggest that UVBR can alter the structure of the lower levels of the planktonic community by selectively affecting key species. On the other hand, linearity between particulate organic carbon (POC) and estimated planktonic carbon was lost during the postbloom period in both treatments. On the basis of previous studies, our results can be attributed to the aggregation of carbon released by cells to the water column in the form of transparent exopolymer particles (TEPs) under nutrient limiting conditions. Unexpectedly, POC during such a period was higher in the H treatment than in controls. We hypothesize a decrease in the ingestion of TEPs by ciliates, in coincidence with increased DOC release by phytoplankton cells under enhanced UVBR. The consequences of such results for the carbon cycle in the ocean are discussed.
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Affiliation(s)
- Gustavo A Ferreyra
- Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, 310 Allée des Ursulines, Canada G5L 3A1.
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35
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Abstract
Water was called by Szent-Gyorgi "life's mater and matrix, mother and medium." This chapter considers both aspects of his statement. Many astrobiologists argue that some, if not all, of Earth's water arrived during cometary bombardments. Amorphous water ices of comets possibly facilitated organization of complex organic molecules, kick-starting prebiotic evolution. In Gaian theory, Earth retains its water as a consequence of biological activity. The cell cytomatrix is a proteinaceous matrix/lattice incorporating the cytoskeleton, a pervasive, holistic superstructural network that integrates metabolic pathways. Enzymes of metabolic pathways are ordered in supramolecular clusters (metabolons) associated with cytoskeleton and/or membranes. Metabolic intermediates are microchanneled through metabolons without entering a bulk aqueous phase. Rather than being free in solution, even major signaling ions are probably clustered in association with the cytomatrix. Chloroplasts and mitochondria, like bacteria and archaea, also contain a cytoskeletal lattice, metabolons, and channel metabolites. Eukaryotic metabolism is mathematically a scale-free or small-world network. Enzyme clusters of bacterial origin are incorporated at a pathway level that is architecturally archaean. The eucaryotic cell may be a product of serial endosymbiosis, a chimera. Cell cytoplasm is approximately 80% water. Water is indisputably a conserved structural element of proteins, essential to their folding, specificity, ligand binding, and to enzyme catalysis. The vast literature of organized cell water has long argued that the cytomatrix and cell water are an entire system, a continuum, or gestalt. Alternatives are offered to mainstream explanations of cell electric potentials, ion channel, enzyme, and motor protein function, in terms of high-order cooperative systems of ions, water, and macromolecules. This chapter describes some prominent concepts of organized cell water, including vicinal water network theory, the association-induction hypothesis, wave-cluster theory, phase-gel transition theories, and theories of low- and high-density water polymorphs.
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Affiliation(s)
- V A Shepherd
- Department of Biophysics, School of Physics, The University of NSW NSW 2052, Sydney, Australia
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Perez-Vilar J, Mabolo R, McVaugh CT, Bertozzi CR, Boucher RC. Mucin granule intraluminal organization in living mucous/goblet cells. Roles of protein post-translational modifications and secretion. J Biol Chem 2005; 281:4844-55. [PMID: 16377632 DOI: 10.1074/jbc.m510520200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent studies suggest that the mucin granule lumen consists of a matrix meshwork embedded in a fluid phase. Secretory products can both diffuse, although very slowly, through the meshwork pores and interact noncovalently with the matrix. Using a green fluorescent protein-mucin fusion protein (SHGFP-MUC5AC/CK) as a FRAP (fluorescence recovery after photobleaching) probe, we have assessed in living mucous cells the relative importance of different protein post-translational modifications on the intragranular organization. Long term inhibition of mucin-type O-glycosylation, sialylation, or sulfation altered SHGFP-MUC5AC/CK characteristic diffusion time (t(1/2)), whereas all but sulfation diminished its mobile fraction. Reduction of protein disulfide bonds with tris(hydroxypropyl)phosphine resulted in virtually complete immobilization of the SHGFP-MUC5AC/CK intragranular pool. However, when activity of the vacuolar H+-ATPase was also inhibited, disulfide reduction decreased SHGFP-MUC5AC/CK t((1/2)) while diminishing its intraluminal concentration. Similar FRAP profiles were observed in granules that remained in the cells after the addition of a mucin secretagogue. Taken together these results suggest that: (a) the relative content of O-glycans and intragranular anionic groups is crucial for protein diffusion through the intragranular meshwork; (b) protein-protein, rather than carbohydrate-mediated, interactions are responsible for binding of SHGFP-MUC5AC/CK to the immobile fraction, although the degree of matrix O-glycosylation and sialylation affects such interactions; (c) intragranular organization does not depend on covalent multimerization of mucins or the presence of native disulfide bonds in the intragranular mucin/proteins, but rather on specific protein-mediated interactions that are important during the early stages of mucin matrix condensation; (d) alterations of the intragranular matrix precede granule discharge, which can be partial and, accordingly, does not necessarily involve the disappearance of the granule.
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Affiliation(s)
- Juan Perez-Vilar
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599-7248, USA.
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Van den Ende W, Yoshida M, Clerens S, Vergauwen R, Kawakami A. Cloning, characterization and functional analysis of novel 6-kestose exohydrolases (6-KEHs) from wheat (Triticum aestivum). THE NEW PHYTOLOGIST 2005; 166:917-32. [PMID: 15869652 DOI: 10.1111/j.1469-8137.2005.01394.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Cereals accumulate graminan-type fructans which are subject to stress-related degradation by fructan 1-exohydrolases (1-FEHs) and fructan 6-exohydrolases (6-FEHs). To find new FEH genes related to freezing tolerance, a cold-hardened wheat crown cDNA library was screened. Here we report the cloning, purification and characterization of two novel 6-kestosidase (6-KEH) isoenzymes from wheat crowns (Triticum aestivum). Functional characterization in Pichia pastoris confirmed the extreme substrate selectivity for the fructan trisaccharide 6-kestose. Northern blotting showed that 6-KEH transcripts were constantly detected at the same level from autumn to winter in crown but not in leaf tissues. Apoplastic fluid isolations and activity measurements strongly suggest that 6-KEH is localized in the apoplast. It is proposed that 6-KEHs, together with other FEHs, might be involved in the breakdown of apoplastic fructans which may fulfil a role as membrane protectors under stress. Alternatively, a role in signalling processes, or in the degradation of exogenous 6-kestose from bacterial origin, cannot be excluded.
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Affiliation(s)
- Wim Van den Ende
- K.U. Leuven, Institute of Botany and Microbiology, Laboratory of Molecular Plant Physiology, Kasteelpark Arenberg 31, B-3001 Heverlee, Belgium.
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Ngo DA, Garland PA, Mandoli DF. Development and organization of the central vacuole of Acetabularia acetabulum. THE NEW PHYTOLOGIST 2005; 165:731-746. [PMID: 15720684 DOI: 10.1111/j.1469-8137.2004.01287.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
* Here we analyzed the shape of the central vacuole of Acetabularia acetabulum by visualizing its development during diplophase (from juvenility through reproduction) and haplophase (from meiosis through mating). * Light microscopy and whole-organism applications of a pH-sensitive dye, neutral red, were used to visualize the anatomy of the central vacuole. We studied connectivity within the thallus by locally applying dye to morphologically distinct regions (rhizoid, stalk, apex, hairs) and observing dye movements. * In vegetative thalli most of the rhizoid, stalk and young hairs stained with dye. In reproductive structures (caps, gametangia) dye also stained the majority of the interiors. When applied to small areas, dye moved at different rates through each region of the thallus (e.g. within the stalk). Dye moved from younger hairs, but not from older hairs, into the stalk. Errors in incorporation of central vacuole into gametangia occurred at <10(-5). * These data indicate that the central vacuole of A. acetabulum is a ramified polar organelle with, potentially, a gel-like sap that actively remodels its morphology during development.
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Affiliation(s)
- Duc A Ngo
- Department of Biology & Center for Developmental Biology, Box 355325, University of Washington, Seattle, WA 98195-5325, USA
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