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Chaumier T, Yang F, Manirakiza E, Ait-Mohamed O, Wu Y, Chandola U, Jesus B, Piganeau G, Groisillier A, Tirichine L. Genome-wide assessment of genetic diversity and transcript variations in 17 accessions of the model diatom Phaeodactylum tricornutum. ISME COMMUNICATIONS 2024; 4:ycad008. [PMID: 38304080 PMCID: PMC10833087 DOI: 10.1093/ismeco/ycad008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/01/2023] [Accepted: 12/13/2023] [Indexed: 02/03/2024]
Abstract
Diatoms, a prominent group of phytoplankton, have a significant impact on both the oceanic food chain and carbon sequestration, thereby playing a crucial role in regulating the climate. These highly diverse organisms show a wide geographic distribution across various latitudes. In addition to their ecological significance, diatoms represent a vital source of bioactive compounds that are widely used in biotechnology applications. In the present study, we investigated the genetic and transcriptomic diversity of 17 accessions of the model diatom Phaeodactylum tricornutum including those sampled a century ago as well as more recently collected accessions. The analysis of the data reveals a higher genetic diversity and the emergence of novel clades, indicating an increasing diversity within the P. tricornutum population structure, compared to the previous study and a persistent long-term balancing selection of genes in old and newly sampled accessions. However, the study did not establish a clear link between the year of sampling and genetic diversity, thereby, rejecting the hypothesis of loss of heterozygoty in cultured strains. Transcript analysis identified novel transcript including noncoding RNA and other categories of small RNA such as PiwiRNAs. Additionally, transcripts analysis using differential expression as well as Weighted Gene Correlation Network Analysis has provided evidence that the suppression or downregulation of genes cannot be solely attributed to loss-of-function mutations. This implies that other contributing factors, such as epigenetic modifications, may play a crucial role in regulating gene expression. Our study provides novel genetic resources, which are now accessible through the platform PhaeoEpiview (https://PhaeoEpiView.univ-nantes.fr), that offer both ease of use and advanced tools to further investigate microalgae biology and ecology, consequently enriching our current understanding of these organisms.
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Affiliation(s)
| | - Feng Yang
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
| | - Eric Manirakiza
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
| | - Ouardia Ait-Mohamed
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, Paris 75005, France
| | - Yue Wu
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
| | - Udita Chandola
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
| | - Bruno Jesus
- Institut des Substances et Organismes de la Mer, ISOMer, Nantes Université, UR 2160, Nantes F-44000, France
| | - Gwenael Piganeau
- Sorbonne Université, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes, LBBM, F-66650 Banyuls-sur-Mer, France
| | | | - Leila Tirichine
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
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Erdene-Ochir E, Shin BK, Kwon B, Jung C, Pan CH. Identification and characterisation of the novel endogenous promoter HASP1 and its signal peptide from Phaeodactylum tricornutum. Sci Rep 2019; 9:9941. [PMID: 31289300 PMCID: PMC6617621 DOI: 10.1038/s41598-019-45786-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 06/10/2019] [Indexed: 12/20/2022] Open
Abstract
Although diatoms have been extensively studied as bioreactors, only a limited number of efficient gene promoters are available. Therefore, the development of new endogenous promoters is important for the heterologous production of a variety of recombinant proteins. Herein, we identified the most abundant secreted protein in Phaeodactylum tricornutum, designated ‘highly abundant secreted protein 1’ (HASP1), and characterised the activities of its promoter and signal peptide using green fluorescent protein (GFP) as a reporter. The HASP1 promoter strongly drove GFP expression during all growth phases of P. tricornutum in culture, in contrast to the commonly used fcpA promoter, which is less active during the stationary phase. The HASP1 signal peptide was also sufficient for facilitating efficient secretion of GFP by P. tricornutum. Our findings suggest that both the promoter and the signal peptide of HASP1 can be utilized as novel tools for the overexpression and secretion of recombinant proteins in P. tricornutum.
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Affiliation(s)
- Erdenedolgor Erdene-Ochir
- Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung, 25451, Republic of Korea.,Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea
| | - Bok-Kyu Shin
- Algaeprona Inc, Gangneung, 25451, Republic of Korea
| | - Byeori Kwon
- Algaeprona Inc, Gangneung, 25451, Republic of Korea
| | - Choonkyun Jung
- Graduate School of International Agricultural Technology and Crop Biotechnology Institute/GreenBio Science and Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea.
| | - Cheol-Ho Pan
- Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung, 25451, Republic of Korea. .,Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea.
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Contribution of ammonia oxidation to chemoautotrophy in Antarctic coastal waters. ISME JOURNAL 2016; 10:2605-2619. [PMID: 27187795 PMCID: PMC5113851 DOI: 10.1038/ismej.2016.61] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 02/04/2016] [Accepted: 03/22/2016] [Indexed: 11/09/2022]
Abstract
There are few measurements of nitrification in polar regions, yet geochemical evidence suggests that it is significant, and chemoautotrophy supported by nitrification has been suggested as an important contribution to prokaryotic production during the polar winter. This study reports seasonal ammonia oxidation (AO) rates, gene and transcript abundance in continental shelf waters west of the Antarctic Peninsula, where Thaumarchaeota strongly dominate populations of ammonia-oxidizing organisms. Higher AO rates were observed in the late winter surface mixed layer compared with the same water mass sampled during summer (mean±s.e.: 62±16 versus 13±2.8 nm per day, t-test P<0.0005). AO rates in the circumpolar deep water did not differ between seasons (21±5.7 versus 24±6.6 nm per day; P=0.83), despite 5- to 20-fold greater Thaumarchaeota abundance during summer. AO rates correlated with concentrations of Archaea ammonia monooxygenase (amoA) genes during summer, but not with concentrations of Archaea amoA transcripts, or with ratios of Archaea amoA transcripts per gene, or with concentrations of Betaproteobacterial amoA genes or transcripts. The AO rates we report (<0.1–220 nm per day) are ~10-fold greater than reported previously for Antarctic waters and suggest that inclusion of Antarctic coastal waters in global estimates of oceanic nitrification could increase global rate estimates by ~9%. Chemoautotrophic carbon fixation supported by AO was 3–6% of annualized phytoplankton primary production and production of Thaumarchaeota biomass supported by AO could account for ~9% of the bacterioplankton production measured in winter. Growth rates of thaumarchaeote populations inferred from AO rates averaged 0.3 per day and ranged from 0.01 to 2.1 per day.
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Algal Community Membership of Estuarine Mudflats from the Savannah River, United States. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2016. [DOI: 10.3390/jmse4010011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Yuan J, Li M, Lin S. An Improved DNA Extraction Method for Efficient and Quantitative Recovery of Phytoplankton Diversity in Natural Assemblages. PLoS One 2015. [PMID: 26218575 PMCID: PMC4517865 DOI: 10.1371/journal.pone.0133060] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Marine phytoplankton are highly diverse with different species possessing different cell coverings, posing challenges for thoroughly breaking the cells in DNA extraction yet preserving DNA integrity. While quantitative molecular techniques have been increasingly used in phytoplankton research, an effective and simple method broadly applicable to different lineages and natural assemblages is still lacking. In this study, we developed a bead-beating protocol based on our previous experience and tested it against 9 species of phytoplankton representing different lineages and different cell covering rigidities. We found the bead-beating method enhanced the final yield of DNA (highest as 2 folds) in comparison with the non-bead-beating method, while also preserving the DNA integrity. When our method was applied to a field sample collected at a subtropical bay located in Xiamen, China, the resultant ITS clone library revealed a highly diverse assemblage of phytoplankton and other micro-eukaryotes, including Archaea, Amoebozoa, Chlorophyta, Ciliphora, Bacillariophyta, Dinophyta, Fungi, Metazoa, etc. The appearance of thecate dinoflagellates, thin-walled phytoplankton and “naked” unicellular organisms indicates that our method could obtain the intact DNA of organisms with different cell coverings. All the results demonstrate that our method is useful for DNA extraction of phytoplankton and environmental surveys of their diversity and abundance.
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Affiliation(s)
- Jian Yuan
- The State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, China
- Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen, Fujian, China
| | - Meizhen Li
- The State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, China
- Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen, Fujian, China
| | - Senjie Lin
- The State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, China
- Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen, Fujian, China
- The Department of Marine Sciences, University of Connecticut, Groton, Connecticut, United States of America
- * E-mail:
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Cimarelli L, Singh KS, Mai NTN, Dhar BC, Brandi A, Brandi L, Spurio R. Molecular tools for the selective detection of nine diatom species biomarkers of various water quality levels. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:5485-504. [PMID: 26006124 PMCID: PMC4454981 DOI: 10.3390/ijerph120505485] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 04/24/2015] [Accepted: 05/04/2015] [Indexed: 11/16/2022]
Abstract
Our understanding of the composition of diatom communities and their response to environmental changes is currently limited by laborious taxonomic identification procedures. Advances in molecular technologies are expected to contribute more efficient, robust and sensitive tools for the detection of these ecologically relevant microorganisms. There is a need to explore and test phylogenetic markers as an alternative to the use of rRNA genes, whose limited sequence divergence does not allow the accurate discrimination of diatoms at the species level. In this work, nine diatom species belonging to eight genera, isolated from epylithic environmental samples collected in central Italy, were chosen to implement a panel of diatoms covering the full range of ecological status of freshwaters. The procedure described in this work relies on the PCR amplification of specific regions in two conserved diatom genes, elongation factor 1-a (eEF1-a) and silicic acid transporter (SIT), as a first step to narrow down the complexity of the targets, followed by microarray hybridization experiments. Oligonucleotide probes with the potential to discriminate closely related species were designed taking into account the genetic polymorphisms found in target genes. These probes were tested, refined and validated on a small-scale prototype DNA chip. Overall, we obtained 17 highly specific probes targeting eEF1-a and SIT, along with 19 probes having lower discriminatory power recognizing at the same time two or three species. This basic array was validated in a laboratory setting and is ready for tests with crude environmental samples eventually to be scaled-up to include a larger panel of diatoms. Its possible use for the simultaneous detection of diatoms selected from the classes of water quality identified by the European Water Framework Directive is discussed.
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Affiliation(s)
- Lucia Cimarelli
- Laboratory of Genetics, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy.
| | - Kumar Saurabh Singh
- Laboratory of Genetics, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy.
| | - Nguyen Thi Nhu Mai
- Laboratory of Genetics, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy.
| | - Bidhan Chandra Dhar
- Laboratory of Genetics, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy.
| | - Anna Brandi
- Laboratory of Genetics, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy.
| | - Letizia Brandi
- Laboratory of Genetics, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy.
| | - Roberto Spurio
- Laboratory of Genetics, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy.
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Molecular detection of a potentially toxic diatom species. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:4921-41. [PMID: 25955528 PMCID: PMC4454946 DOI: 10.3390/ijerph120504921] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 03/24/2015] [Accepted: 04/16/2015] [Indexed: 12/27/2022]
Abstract
A few diatom species produce toxins that affect human and animal health. Among these, members of the Pseudo-nitzschia genus were the first diatoms unambiguously identified as producer of domoic acid, a neurotoxin affecting molluscan shell-fish, birds, marine mammals, and humans. Evidence exists indicating the involvement of another diatom genus, Amphora, as a potential producer of domoic acid. We present a strategy for the detection of the diatom species Amphora coffeaeformis based on the development of species-specific oligonucleotide probes and their application in microarray hybridization experiments. This approach is based on the use of two marker genes highly conserved in all diatoms, but endowed with sufficient genetic divergence to discriminate diatoms at the species level. A region of approximately 450 bp of these previously unexplored marker genes, coding for elongation factor 1-a (eEF1-a) and silicic acid transporter (SIT), was used to design oligonucleotide probes that were tested for specificity in combination with the corresponding fluorescently labeled DNA targets. The results presented in this work suggest a possible use of this DNA chip technology for the selective detection of A. coffeaeformis in environmental settings where the presence of this potential toxin producer may represent a threat to human and animal health. In addition, the same basic approach can be adapted to a wider range of diatoms for the simultaneous detection of microorganisms used as biomarkers of different water quality levels.
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A Simple Novel Agar Diffusion Method for Isolation of Indigenous Microalgae Chlamydomonas sp. CRP7 and Chlorella sp. CB4 from Operational Swampy Top Soil. Indian J Microbiol 2012; 52:710-2. [PMID: 24293736 DOI: 10.1007/s12088-012-0295-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 07/20/2012] [Indexed: 10/28/2022] Open
Abstract
A simple agar diffusion method is developed where pure colony of Chlamydomonas sp. CRP7 was isolated from Chlorella sp. CB4 mixtures by passing through agar migration with a light exposure of 6,000 lux for 7 h. The main concept behind it is that Chlamydomonas has flagella and the rhodopsin pigment is attracted towards light. Thus the above two microalgae species can be separated from the mixtures as eye spot serves as a navigator and flagella serves as a propeller for Chlamydomonas spp. Further the genomic DNA was isolated and purified from the above mentioned two species after the separation from the mixtures. PCR amplification was carried out for ITS1, 5.8S and ITS2 regions. The amplified products were sequenced and the sequence analysis confirmed that they belong to Chlamydomonas sp. and Chlorella sp. This is an important augmentation for isolation and separation of microalgae.
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Baldi F, Facca C, Marchetto D, Nguyen TNM, Spurio R. Diatom quantification and their distribution with salinity brines in coastal sediments of Terra Nova Bay (Antarctica). MARINE ENVIRONMENTAL RESEARCH 2011; 71:304-311. [PMID: 21414661 DOI: 10.1016/j.marenvres.2011.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/15/2011] [Accepted: 02/18/2011] [Indexed: 05/30/2023]
Abstract
Benthic diatoms represent an important element of global nutritional productivity; to raise attention on their role, which is often neglected due to analytical difficulties, surface (1 cm top layer) coastal sediments from Gerlache inlet to Penguin Bay at Terra Nova Bay were collected and stored at -20 °C. DNA amplification by real-time PCR, based on diatom-specific oligonucleotide primers designed on small-subunit rRNA (SSU rRNA), was performed in addition to diatom conventional cell counting and spectrophotometric determination of photo-pigments. Moreover, cations and anions were determined in sediments with the aim to identify factors involved in the control of diatom abundance. Diatom distribution was found quite heterogeneous displaying significant differences from site to site. The salinity in sediments ranged from 45.1 at Gerlache inlet to 76.2 at Penguin Bay and it was correlated with cell abundance, biodiversity, amount of pigments and amplified DNA. The dominant species, Fragilariopsis curta, was associated to sediment salinity brines.
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Affiliation(s)
- Franco Baldi
- Department of Environmental Sciences, Ca' Foscari University of Venezia, Calle Larga S. Marta Dorsoduro 2137, 30123 Venezia, Italy.
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