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Li J, Wang Z, Yang H, Wang Z, Liu F, Chen X, Huang X. Phosphorus forms and zinc concentrations affect the physiological ecology and sinking rate of Thalassiosira weissflogii. MARINE POLLUTION BULLETIN 2024; 200:116124. [PMID: 38325204 DOI: 10.1016/j.marpolbul.2024.116124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/01/2024] [Accepted: 02/01/2024] [Indexed: 02/09/2024]
Abstract
The combined effects of phosphorus (P) forms and zinc (Zn) concentrations on diatom silicification remain unclear. In this study, we investigate the effects of different Zn concentrations on the growth, cellular silicon content and sinking rate of Thalassiosira weissflogii under different P forms. The results showed that under the dissolved inorganic phosphorus (DIP) treatments, the specific growth rate of T. weissflogii in Zn limitation culture was significantly lower than that in Zn-replete culture. However, T. weissflogii cellular silicon content and sinking rate increased. Moreover, the reduced specific growth rate (7 %, p < 0.05), enhanced ALP activity (63 %, p < 0.05), and sinking rate (20 %, p < 0.05) for Zn-deplete T. weissflogii implied that the bioavailability of dissolved organic phosphorus (DOP) was depressed under Zn deplete medium. This study demonstrates that the physiological ecology and sinking rate of the diatom T. weissflogii were affected by both individual and combined changes in P forms and Zn concentrations.
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Affiliation(s)
- Jiandi Li
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Zhaofei Wang
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Hang Yang
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Zhenfeng Wang
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Fengjiao Liu
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 363000, China
| | - Xiaohuang Chen
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 363000, China
| | - Xuguang Huang
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 363000, China.
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Bryłka K, Pinseel E, Roberts WR, Ruck EC, Conley DJ, Alverson AJ. Gene Duplication, Shifting Selection, and Dosage Balance of Silicon Transporter Proteins in Marine and Freshwater Diatoms. Genome Biol Evol 2023; 15:evad212. [PMID: 37996067 PMCID: PMC10700740 DOI: 10.1093/gbe/evad212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/15/2023] [Accepted: 11/17/2023] [Indexed: 11/25/2023] Open
Abstract
Numerous factors shape the evolution of protein-coding genes, including shifts in the strength or type of selection following gene duplications or changes in the environment. Diatoms and other silicifying organisms use a family of silicon transporters (SITs) to import dissolved silicon from the environment. Freshwaters contain higher silicon levels than oceans, and marine diatoms have more efficient uptake kinetics and less silicon in their cell walls, making them better competitors for a scarce resource. We compiled SITs from 37 diatom genomes to characterize shifts in selection following gene duplications and marine-freshwater transitions. A deep gene duplication, which coincided with a whole-genome duplication, gave rise to two gene lineages. One of them (SIT1-2) is present in multiple copies in most species and is known to actively import silicon. These SITs have evolved under strong purifying selection that was relaxed in freshwater taxa. Episodic diversifying selection was detected but not associated with gene duplications or habitat shifts. In contrast, genes in the second SIT lineage (SIT3) were present in just half the species, the result of multiple losses. Despite conservation of SIT3 in some lineages for the past 90-100 million years, repeated losses, relaxed selection, and low expression highlighted the dispensability of SIT3, consistent with a model of deterioration and eventual loss due to relaxed selection on SIT3 expression. The extensive but relatively balanced history of duplications and losses, together with paralog-specific expression patterns, suggest diatoms continuously balance gene dosage and expression dynamics to optimize silicon transport across major environmental gradients.
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Affiliation(s)
| | - Eveline Pinseel
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Wade R Roberts
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Elizabeth C Ruck
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | | | - Andrew J Alverson
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
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Galachyants YP, Zakharova YR, Volokitina NA, Morozov AA, Likhoshway YV, Grachev MA. De novo transcriptome assembly and analysis of the freshwater araphid diatom Fragilaria radians, Lake Baikal. Sci Data 2019; 6:183. [PMID: 31562323 PMCID: PMC6765018 DOI: 10.1038/s41597-019-0191-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 08/13/2019] [Indexed: 11/08/2022] Open
Abstract
Diatoms are a group of eukaryotic microalgae populating almost all aquatic and wet environments. Their abundance and species diversity make these organisms significant contributors to biogeochemical cycles and important components of aquatic ecosystems. Although significant progress has been made in studies of Diatoms (Bacillariophyta) over the last two decades, since the spread of "omics" technologies, our current knowledge of the molecular processes and gene regulatory networks that facilitate environmental adaptation remain incomplete. Here, we present a transcriptome analysis of Fragilaria radians isolated from Lake Baikal. The resulting assembly contains 27,446 transcripts encoding 21,996 putative proteins. The transcriptome assembly and annotation were coupled with quantitative experiments to search for differentially expressed transcripts between (i) exponential growth phase and dark-acclimated cell cultures, and (ii) those changing expression level during the early response to light treatment in dark-acclimated cells. The availability of F. radians genome and transcriptome data provides the basis for future targeted studies of this species. Furthermore, our results extend taxonomic and environmental sampling of Bacillariophyta, opening new opportunities for comparative omics-driven surveys.
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Affiliation(s)
- Yuri Pavlovich Galachyants
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 664033, 3 Ulan-Batorskaya st., Irkutsk, Russia.
| | - Yulia Robertovna Zakharova
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 664033, 3 Ulan-Batorskaya st., Irkutsk, Russia
| | - Nadezda Antonovna Volokitina
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 664033, 3 Ulan-Batorskaya st., Irkutsk, Russia
| | - Alexey Anatolyevich Morozov
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 664033, 3 Ulan-Batorskaya st., Irkutsk, Russia
| | - Yelena Valentinovna Likhoshway
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 664033, 3 Ulan-Batorskaya st., Irkutsk, Russia
| | - Mikhail Aleksandrovich Grachev
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 664033, 3 Ulan-Batorskaya st., Irkutsk, Russia
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Marchenkov AM, Petrova DP, Morozov AA, Zakharova YR, Grachev MA, Bondar AA. A family of silicon transporter structural genes in a pennate diatom Synedra ulna subsp. danica (Kütz.) Skabitsch. PLoS One 2018; 13:e0203161. [PMID: 30157241 PMCID: PMC6114903 DOI: 10.1371/journal.pone.0203161] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 08/15/2018] [Indexed: 11/19/2022] Open
Abstract
Silicon transporters (SIT) are the proteins, which capture silicic acid in the aquatic environment and direct it across the plasmalemma to the cytoplasm of diatoms. Diatoms utilize silicic acid to build species-specific ornamented exoskeletons and make a significant contribution to the global silica cycle, estimated at 240 ±40 Tmol a year. Recently SaSIT genes of the freshwater araphid pennate diatom Synedra acus subsp. radians are found to be present in the genome as a cluster of two structural genes (SaSIT-TD and SaSIT-TRI) encoding several concatenated copies of a SIT protein each. These structural genes could potentially be transformed into "mature" SIT proteins by means of posttranslational proteolytic cleavage. In the present study, we discovered three similar structural SuSIT genes in the genome of a closely related freshwater diatom Synedra ulna subsp. danica. Structural gene SuSIT1 is identical to structural gene SuSIT2, and the two are connected by a non-coding nucleotide DNA sequence. All the putative "mature" SITs contain conserved amino acid motifs, which are believed to be important in silicon transport. The data obtained suggest that the predicted "mature" SIT proteins may be the minimal units necessary for the transport of silicon is S. ulna subsp. danica. The comparative analysis of all available multi-SITs has allowed us to detect two conservative motifs YQXDXVYL and DXDID, located between the "mature" proteins. Aspartic acid-rich DXDID motif can, in our opinion, serve as a proteolysis site during the multi-SIT cleavage. The narrow distribution of the distances between CMLD and DXDID motifs can serve as additional evidence to the conservation of their function.
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Affiliation(s)
- Artyom M. Marchenkov
- Department of Cell Ultrastructure, Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
| | - Darya P. Petrova
- Department of Cell Ultrastructure, Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
| | - Alexey A. Morozov
- Department of Cell Ultrastructure, Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
| | - Yulia R. Zakharova
- Department of Cell Ultrastructure, Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
| | - Michael A. Grachev
- Department of Cell Ultrastructure, Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
| | - Alexander A. Bondar
- Genomics Core Facility, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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Ma J, Zhang X, Wang L. Synergistic effects between [Si-hemicellulose matrix] ligands and Zn ions in inhibiting Cd ion uptake in rice (Oryza sativa) cells. PLANTA 2017; 245:965-976. [PMID: 28138761 DOI: 10.1007/s00425-017-2655-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 01/22/2017] [Indexed: 06/06/2023]
Abstract
Our study demonstrated that Zn alleviated Cd toxicity in the presence of Si in the cell walls by Zn 2+ binding to ligands through the formation of the [Si-hemicellulose matrix]Zn complexes that restrict the uptake of Cd. The plant cell wall exhibits preferential sites for the accumulation of metals at toxic concentrations. Through modification of wall polysaccharide components, elements, such as silicon (Si) and zinc (Zn), may play active roles in alleviating the toxicity of heavy metals, including cadmium (Cd). However, enhanced tolerance for Cd stress may rely on synergistic effects between nutrient elements. Here, we cultured Si-accumulating suspension cells of rice (Oryza sativa) exposed to Cd and Zn treatments, either separately or in combination, and investigated cells using noninvasive microtest technology (NMT), inductively coupled plasma mass spectroscopy (ICP-MS) and atomic force microscopy (AFM). We found that Zn alleviated Cd toxicity in the presence of Si in the cell walls by binding of Zn2+ to ligands through the formation of the [Si-hemicellulose matrix]Zn complexes and co-precipitates to greatly inhibit Cd2+ uptake into cells. This, in turn, induced the lower expression of Cd-related transporters. This synergistic effect could be decisive for the survival of cells under conditions of high Cd concentrations.
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Affiliation(s)
- Jie Ma
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiuqing Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
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6
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Marchenkov AM, Bondar AA, Petrova DP, Habudaev KV, Galachyants YP, Zakharova YR, Volokitina NA, Grachev MA. Unique configuration of genes of silicon transporter in the freshwater pennate diatom Synedra acus subsp. radians. DOKL BIOCHEM BIOPHYS 2017; 471:407-409. [PMID: 28058681 DOI: 10.1134/s1607672916060089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Indexed: 11/23/2022]
Abstract
The existence of the cluster of duplicated sit silicon transporter genes in the chromosome of the diatom Synedra acus subsp. radians was shown for the first time. Earlier, the localization of sit genes in the same chromosome and cluster formation caused by gene duplication was shown only for the marine raphid pennate diatom P. tricornutum. Only non-clustered sit genes were found in the genomes of other diatoms. It is reasonable to assume that sit tandem (sit-td) and sit triplet (sit-tri) genes of S. acus subsp. radians occurred as a result of gene duplication followed by divergence of gene copies.
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Affiliation(s)
- A M Marchenkov
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, ul. Ulan-Batorskaya 3, Irkutsk, 664033, Russia.
| | - A A Bondar
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent'eva 8, Novosibirsk, 630090, Russia
| | - D P Petrova
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, ul. Ulan-Batorskaya 3, Irkutsk, 664033, Russia
| | - K V Habudaev
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, ul. Ulan-Batorskaya 3, Irkutsk, 664033, Russia
| | - Yu P Galachyants
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, ul. Ulan-Batorskaya 3, Irkutsk, 664033, Russia
| | - Yu R Zakharova
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, ul. Ulan-Batorskaya 3, Irkutsk, 664033, Russia
| | - N A Volokitina
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, ul. Ulan-Batorskaya 3, Irkutsk, 664033, Russia
| | - M A Grachev
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, ul. Ulan-Batorskaya 3, Irkutsk, 664033, Russia
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7
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Kharitonenko KV, Bedoshvili YD, Likhoshway YV. Changes in the micro- and nanostructure of siliceous valves in the diatom Synedra acus under the effect of colchicine treatment at different stages of the cell cycle. J Struct Biol 2015; 190:73-80. [DOI: 10.1016/j.jsb.2014.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 12/10/2014] [Accepted: 12/17/2014] [Indexed: 01/07/2023]
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Shrestha RP, Hildebrand M. Evidence for a regulatory role of diatom silicon transporters in cellular silicon responses. EUKARYOTIC CELL 2015; 14:29-40. [PMID: 25380754 PMCID: PMC4279021 DOI: 10.1128/ec.00209-14] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 11/03/2014] [Indexed: 01/19/2023]
Abstract
The utilization of silicon by diatoms has both global and small-scale implications, from oceanic primary productivity to nanotechnological applications of their silica cell walls. The sensing and transport of silicic acid are key aspects of understanding diatom silicon utilization. At low silicic acid concentrations (<30 μM), transport mainly occurs through silicic acid transport proteins (SITs), and at higher concentrations it occurs through diffusion. Previous analyses of the SITs were done either in heterologous systems or without a distinction between individual SITs. In the present study, we examined individual SITs in Thalassiosira pseudonana in terms of transcript and protein abundance in response to different silicic acid regimes and examined knockdown lines to evaluate the role of the SITs in transport, silica incorporation, and lipid accumulation resulting from silicon starvation. SIT1 and SIT2 were localized in the plasma membrane, and protein levels were generally inversely correlated with cellular silicon needs, with a distinct response being found when the two SITs were compared. We developed highly effective approaches for RNA interference and antisense knockdowns, the first such approaches developed for a centric diatom. SIT knockdown differentially affected the uptake of silicon and the incorporation of silicic acid and resulted in the induction of lipid accumulation under silicon starvation conditions far earlier than in the wild-type cells, suggesting that the cells were artificially sensing silicon limitation. The data suggest that the transport role of the SITs is relatively minor under conditions with sufficient silicic acid. Their primary role is to sense silicic acid levels to evaluate whether the cell can proceed with its cell wall formation and division processes.
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Affiliation(s)
- Roshan P Shrestha
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Mark Hildebrand
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
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Shishlyannikov SM, Klimenkov IV, Bedoshvili YD, Mikhailov IS, Gorshkov AG. Effect of mixotrophic growth on the ultrastructure and fatty acid composition of the diatom Synedra acus from Lake Baikal. JOURNAL OF BIOLOGICAL RESEARCH (THESSALONIKE, GREECE) 2014; 21:15. [PMID: 25984498 PMCID: PMC4389971 DOI: 10.1186/2241-5793-21-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 06/26/2014] [Indexed: 12/26/2022]
Abstract
BACKGROUND Interest in studies concerning the effect of organic carbon sources on the growth of diatoms is largely aimed at subsequent physiological changes occurring in their cells. There are no data on structural changes in the cytoplasm and their relationship with changes in the composition of fatty acids in the course of mixotrophic culturing of freshwater diatoms. To elucidate the role of lipids in the growth of diatom cells in autotrophic and mixotrophic cultures, it is necessary to obtain information on the distribution of fatty acids among intracellular compartments and on possible ultrastructural changes in the cells. RESULTS In this study, the results demonstrated that Synedra acus cells cultured in the presence of 80 mM glycerol contained lipid bodies of increased size, while cells from cultures supplemented with 40 mM glucose accumulated polysaccharide (chrysolaminarin) granules. An increase in the relative amounts of palmitic and stearic acids was revealed at the exponential growth phase of S. acus in the medium with 80 mM glycerol, which was indicative of the accumulation of fatty acids contained in triacylglycerols. CONCLUSIONS Synedra acus subsp. radians have an ability to proliferate in the presence of high concentrations of organic substances and their transport into cells is evidence for its high adaptation potential, which, along with other factors, accounts for the dominance of this diatom in the spring-summer plankton of the oligotrophic Lake Baikal.
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Affiliation(s)
- Sergey M Shishlyannikov
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia
| | - Igor V Klimenkov
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia
| | - Yekaterina D Bedoshvili
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia
| | - Ivan S Mikhailov
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia
| | - Alexander G Gorshkov
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia
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10
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Du C, Liang JR, Chen DD, Xu B, Zhuo WH, Gao YH, Chen CP, Bowler C, Zhang W. iTRAQ-based proteomic analysis of the metabolism mechanism associated with silicon response in the marine diatom Thalassiosira pseudonana. J Proteome Res 2014; 13:720-34. [PMID: 24372006 DOI: 10.1021/pr400803w] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Silicon is a critical element for diatom growth; however our understanding of the molecular mechanisms involved in intracellular silicon responses are limited. In this study, an iTRAQ-LC-MS/MS quantitative proteomic approach was coupled with an established synchrony technique to reveal the global metabolic silicon-response in the model diatom Thalassiosira pseudonana subject to silicon starvation and readdition. Four samples, which corresponded to the time of silicon starvation, girdle band synthesis, valve formation, and right after daughter cell separation (0, 1, 5, 7 h), were collected for the proteomic analysis. The results indicated that a total of 1,831 proteins, representing 16% of the predicted proteins encoded by the T. pseudonana genome, could be identified. Of the identified proteins, 165 were defined as being differentially expressed proteins, and these proteins could be linked to multiple biochemical pathways. In particular, a number of proteins related to silicon transport, cell wall synthesis, and cell-cycle progress could be identified. In addition, other proteins that are potentially involved in amino acid synthesis, protein metabolism, and energy generation may have roles in the cellular response to silicon. Our findings provide a range of valuable information that will be of use for further studies of this important physiological response that is unique to diatoms.
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Affiliation(s)
- Chao Du
- School of Life Sciences, Xiamen University , Xiamen 361005, China
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11
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Marron AO, Alston MJ, Heavens D, Akam M, Caccamo M, Holland PWH, Walker G. A family of diatom-like silicon transporters in the siliceous loricate choanoflagellates. Proc Biol Sci 2013; 280:20122543. [PMID: 23407828 PMCID: PMC3574361 DOI: 10.1098/rspb.2012.2543] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 01/17/2013] [Indexed: 11/12/2022] Open
Abstract
Biosilicification is widespread across the eukaryotes and requires concentration of silicon in intracellular vesicles. Knowledge of the molecular mechanisms underlying this process remains limited, with unrelated silicon-transporting proteins found in the eukaryotic clades previously studied. Here, we report the identification of silicon transporter (SIT)-type genes from the siliceous loricate choanoflagellates Stephanoeca diplocostata and Diaphanoeca grandis. Until now, the SIT gene family has been identified only in diatoms and other siliceous stramenopiles, which are distantly related to choanoflagellates among the eukaryotes. This is the first evidence of similarity between SITs from different eukaryotic supergroups. Phylogenetic analysis indicates that choanoflagellate and stramenopile SITs form distinct monophyletic groups. The absence of putative SIT genes in any other eukaryotic groups, including non-siliceous choanoflagellates, leads us to propose that SIT genes underwent a lateral gene transfer event between stramenopiles and loricate choanoflagellates. We suggest that the incorporation of a foreign SIT gene into the stramenopile or choanoflagellate genome resulted in a major metabolic change: the acquisition of biomineralized silica structures. This hypothesis implies that biosilicification has evolved multiple times independently in the eukaryotes, and paves the way for a better understanding of the biochemical basis of silicon transport through identification of conserved sequence motifs.
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Affiliation(s)
- Alan O Marron
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK.
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12
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Varela DE, Willers V, Crawford DW. EFFECT OF ZINC AVAILABILITY ON GROWTH, MORPHOLOGY, AND NUTRIENT INCORPORATION IN A COASTAL AND AN OCEANIC DIATOM(1). JOURNAL OF PHYCOLOGY 2011; 47:302-312. [PMID: 27021862 DOI: 10.1111/j.1529-8817.2010.00948.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We investigated the effect of Zn availability on growth rate (μ), cell morphology, and elemental stoichiometry and incorporation rate in two marine diatoms. For the coastal diatom Skeletonema costatum (Grev.) Cleve, the half-saturation constant (KS ) for growth was 4.1 pM Zn(2+) , and growth ceased at ≤ 2.6 pM Zn(2+) , whereas for the oceanic diatom Thalassiosira oceanica Hasle, KS was 0.5 pM Zn(2+) , and μ remained at ∼40%μmax even at 0.3 pM Zn(2+) . Under Zn-limiting (Zn-L) conditions, S. costatum decreased cell size significantly, leading to an 80% increase in surface area to volume ratio (SA/V) at Zn(2+) of 3.5 pM compared to Zn-replete (Zn-R) conditions (at Zn(2+) of 13.2 pM), whereas T. oceanica's morphology did not change appreciably. Cell quotas of C, N, P, Si, and chl a significantly decreased under Zn limitation in S. costatum (at Zn(2+) of 3.5 pM), whereas Zn limitation in T. oceanica (at Zn(2+) of 0.3 pM) had little effect on quotas. Elemental stoichiometry was ∼85C:10N:9Si:1P and 81C:9N:5Si:1P for S. costatum, and 66C:5N:2Si:1P and 52C:6N:2Si:1P for T. oceanica, under Zn-R and Zn-L conditions, respectively. Incorporation rates of all elements were significantly reduced under Zn limitation for both diatoms, but particularly for Si in S. costatum, and for C in T. oceanica, despite its apparent tolerance of low Zn conditions. With [Zn(2+) ] in some parts of the ocean being of the same order (∼0.2 to 2 pM) as our low Zn conditions for T. oceanica, our results support the hypothesis that in situ growth and C acquisition may be limited by Zn in some oceanic species.
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Affiliation(s)
- Diana E Varela
- Department of Biology, and School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3N5, CanadaDepartment of Biology, University of Victoria, Victoria, British Columbia V8W 3N5, Canada
| | - Valeria Willers
- Department of Biology, and School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3N5, CanadaDepartment of Biology, University of Victoria, Victoria, British Columbia V8W 3N5, Canada
| | - David W Crawford
- Department of Biology, and School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3N5, CanadaDepartment of Biology, University of Victoria, Victoria, British Columbia V8W 3N5, Canada
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13
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Danilovtseva E, Aseyev V, Karesoja M, Annenkov V. Sorption of silicic acid from non-saturated aqueous solution by a complex of zinc ions with poly(vinylamine). Eur Polym J 2009. [DOI: 10.1016/j.eurpolymj.2009.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Affiliation(s)
- Mark Hildebrand
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0202
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Petrova DP, Bedoshvili YD, Shelukhina IV, Samukov VV, Korneva ES, Vereshagin AL, Popkova TP, Karpyshev NN, Lebedeva DV, Klimenkov IV, Likhoshway YV, Grachev MA. Detection of the silicic acid transport protein in the freshwater diatom Synedra acus by immunoblotting and immunoelectron microscopy. DOKL BIOCHEM BIOPHYS 2008; 417:295-8. [PMID: 18274442 DOI: 10.1134/s1607672907060014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- D P Petrova
- Limnological Institute, Siberian Division, Russian Academy of Sciences, ul. Ulan-Batorskaya 3, Irkutsk 664033, Russia
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Grachev MA, Annenkov VV, Likhoshway YV. Silicon nanotechnologies of pigmented heterokonts. Bioessays 2008; 30:328-37. [DOI: 10.1002/bies.20731] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Safonova TA, Annenkov VV, Chebykin EP, Danilovtseva EN, Likhoshway YV, Grachev MA. Aberration of morphogenesis of siliceous frustule elements of the diatom Synedra acus in the presence of germanic acid. BIOCHEMISTRY (MOSCOW) 2007; 72:1261-9. [DOI: 10.1134/s0006297907110132] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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