1
|
Bowazolo C, Morse D. Insights into daily metabolic changes of the dinoflagellate Lingulodinium from ribosome profiling. Cell Cycle 2023; 22:1343-1352. [PMID: 37125841 PMCID: PMC10228409 DOI: 10.1080/15384101.2023.2206771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 05/02/2023] Open
Abstract
The dinoflagellate Lingulodinium specializes its metabolism to perform different tasks better at specific times of day. For example, cells are specialized for photosynthesis during the day and bioluminescence and cell division at night. These rhythms are circadian as they are controlled by an endogenous circadian clock whose mechanism is currently unknown. Despite this, the metabolic rhythms follow coordinated changes in gene expression that occur at a translational level. These changes are revealed by ribosome profiling, a surrogate measure of protein synthesis rates in vivo. Lingulodinium regulates the synthesis rate of over three thousand transcripts. Peak synthesis rates for the different transcripts are clustered around three different times over a light/dark cycle. Furthermore, transcripts involved in the same metabolic process are coordinately regulated. We review the basic principles underlying the correlation of coordinated translation of cell metabolic pathway enzymes with known circadian rhythms, and offer examples where previously unsuspected rhythms are suggested by synchronized changes in gene expression.
Collapse
Affiliation(s)
- Carl Bowazolo
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
| | - David Morse
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
| |
Collapse
|
2
|
Nitrogen and Iron Availability Drive Metabolic Remodeling and Natural Selection of Diverse Phytoplankton during Experimental Upwelling. mSystems 2022; 7:e0072922. [PMID: 36036504 PMCID: PMC9599627 DOI: 10.1128/msystems.00729-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Nearly half of carbon fixation and primary production originates from marine phytoplankton, and much of it occurs in episodic blooms in upwelling regimes. Here, we simulated blooms limited by nitrogen and iron by incubating Monterey Bay surface waters with subnutricline waters and inorganic nutrients and measured the whole-community transcriptomic response during mid- and late-bloom conditions. Cell counts revealed that centric and pennate diatoms (largely Pseudo-nitzschia and Chaetoceros spp.) were the major blooming taxa, but dinoflagellates, prasinophytes, and prymnesiophytes also increased. Viral mRNA significantly increased in late bloom and likely played a role in the bloom's demise. We observed conserved shifts in the genetic similarity of phytoplankton populations to cultivated strains, indicating adaptive population-level changes in community composition. Additionally, the density of single nucleotide variants (SNVs) declined in late-bloom samples for most taxa, indicating a loss of intraspecific diversity as a result of competition and a selective sweep of adaptive alleles. We noted differences between mid- and late-bloom metabolism and differential regulation of light-harvesting complexes (LHCs) under nutrient stress. While most LHCs are diminished under nutrient stress, we showed that diverse taxa upregulated specialized, energy-dissipating LHCs in low iron. We also suggest the relative expression of NRT2 compared to the expression of GSII as a marker of cellular nitrogen status and the relative expression of iron starvation-induced protein genes (ISIP1, ISIP2, and ISIP3) compared to the expression of the thiamine biosynthesis gene (thiC) as a marker of iron status in natural diatom communities. IMPORTANCE Iron and nitrogen are the nutrients that most commonly limit phytoplankton growth in the world's oceans. The utilization of these resources by phytoplankton sets the biomass available to marine systems and is of particular interest in high-nutrient, low-chlorophyll (HNLC) coastal fisheries. Previous research has described the biogeography of phytoplankton in HNLC regions and the transcriptional responses of representative taxa to nutrient limitation. However, the differential transcriptional responses of whole phytoplankton communities to iron and nitrogen limitation has not been previously described, nor has the selective pressure that these competitive bloom environments exert on major players. In addition to describing changes in the physiology of diverse phytoplankton, we suggest practical indicators of cellular nitrogen and iron status for future monitoring.
Collapse
|
3
|
Yu S, Qiao X, Song X, Yang Y, Zhang D, Sun W, Wang L, Song L. The proliferating cell nuclear antigen (PCNA) is a potential proliferative marker in oyster Crassostrea gigas. FISH & SHELLFISH IMMUNOLOGY 2022; 122:306-315. [PMID: 35176468 DOI: 10.1016/j.fsi.2022.02.018] [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: 12/18/2021] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Proliferating cell nuclear antigen (PCNA) is a crucial eukaryotic replication accessory factor in the regulation of DNA synthesis, which is always used as a proliferation marker for haematopoiesis in vertebrates. In the present study, a homologue of PCNA (named as CgPCNA) with a conserved N-terminal PCNA domain and a C-terminal PCNA domain was identified from oyster Crassostrea gigas. The deduced amino acid sequence of CgPCNA shared 85.4% and 86.6% similarities with the PCNAs identified in Mus musculus and Homo sapiens, respectively. CgPCNA was firstly clustered with PCNAs from molluscs, and then with PCNAs from arthropods to form a group falling into the invertebrate clade in the phylogenic tree. The mRNA transcripts of CgPCNA were detected in all tested tissues with higher expression level in gonad, gills and haemolymph. They were also detected in granulocytes, semi-granulocytes and agranulocytes with no significant differences, but the protein level of CgPCNA in agranulocytes was significantly higher (3.67-fold, p < 0.05) than that in granulocytes. In the haemocytes, CgPCNA was mainly distributed in the nucleus and less in the cytoplasm of haemocytes. CgPCNA protein was observed at the tubule lumen regions of gills vessels, and especially colocalized with the EdU signals. After lipopolysaccharide (LPS) and Vibrio splendidus stimulation, the expression level of CgPCNA mRNA in haemocytes was significantly (p < 0.05) up-regulated at 6 h and 12 h, which was 13.87-fold and 3.89-fold of that in control, respectively. In the oysters treated with the recombinant protein CgAstakine (rCgAstakine), the protein abundance of CgPCNA was enhanced in agranulocytes and gills, while no significant change was observed in semi-granulocytes and granulocytes. These results collectively indicated that CgPCNA was highly expressed in the newborn agranulocytes and the potential haematopoietic sites, and it might be applied as a marker for haemocytes proliferation in oysters.
Collapse
Affiliation(s)
- Simiao Yu
- School of Life Science, Liaoning Normal University, Dalian, 116029, China; Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China
| | - Xue Qiao
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China
| | - Xiaorui Song
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China
| | - Ying Yang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China
| | - Dan Zhang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China
| | - Wending Sun
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China
| | - Lingling Wang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian, 116023, China
| | - Linsheng Song
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian, 116023, China.
| |
Collapse
|
4
|
Guo X, Wang Z, Liu L, Li Y. Transcriptome and metabolome analyses of cold and darkness-induced pellicle cysts of Scrippsiella trochoidea. BMC Genomics 2021; 22:526. [PMID: 34246248 PMCID: PMC8272339 DOI: 10.1186/s12864-021-07840-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 06/24/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Dinoflagellates are a group of unicellular organisms that are a major component of aquatic eukaryotes and important contributors to marine primary production. Nevertheless, many dinoflagellates are considered harmful algal bloom (HAB) species due to their detrimental environmental and human health impacts. Cyst formation is widely perceived as an adaptive strategy of cyst-forming dinoflagellates in response to adverse environmental conditions. Dinoflagellate cysts play critical roles in bloom dynamics. However, our insight into the underlying molecular basis of encystment is still limited. To investigate the molecular processes regulating encystment in dinoflagellates, transcriptome and metabolome investigations were performed on cold and darkness-induced pellicle cysts of Scrippsiella trochoidea. RESULTS No significant transcriptional response was observed at 2 h; however, massive transcriptome and metabolome reprogramming occurred at 5 h and in pellicle cysts. The gene-to-metabolite network demonstrated that the initial transformation from vegetative cells into pellicle cysts was highly energy demanding through the activation of catabolism, including glycolysis, β-oxidation, TCA cycle and oxidative phosphorylation, to cope with cold-darkness-induced stress. However, after transformation into pellicle cysts, the metabolism was greatly reduced, and various sugars, polyunsaturated fatty acids and amino acids accumulated to prolong survival. The identification of 56 differentially expressed genes (DEGs) related to signal transduction indicated that S. trochoidea received a cold-darkness signal that activated multiple signal transduction pathways, leading to encystment. The elevated expression of genes encoding enzymes involved in ROS stress suggested that pellicle cysts respond to increased oxidative stress. Several cell cycle-related genes were repressed. Intriguingly, 11 DEGs associated with sexual reproduction suggested that pellicle cysts (or some portion thereof) may be a product of sexual reproduction. CONCLUSIONS This study provides the first transcriptome and metabolome analyses conducted during the encystment of S. trochoidea, an event that requires complex regulatory mechanisms and impacts on population dynamics. The results reveal comprehensive molecular regulatory processes underlying life cycle regulation in dinoflagellates involving signal transduction, gene expression and metabolite profile, which will improve our ability to understand and monitor dinoflagellate blooms.
Collapse
Affiliation(s)
- Xin Guo
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, School of Life Science, South China Normal University, West 55 of Zhongshan Avenue, 510631, Guangzhou, China.,Department of Ecology, College of Life Science and Technology, Jinan University, West 601 of Huangpu Avenue, 510632, Guangzhou, China
| | - Zhaohui Wang
- Department of Ecology, College of Life Science and Technology, Jinan University, West 601 of Huangpu Avenue, 510632, Guangzhou, China.
| | - Lei Liu
- Department of Ecology, College of Life Science and Technology, Jinan University, West 601 of Huangpu Avenue, 510632, Guangzhou, China
| | - Yang Li
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, School of Life Science, South China Normal University, West 55 of Zhongshan Avenue, 510631, Guangzhou, China.
| |
Collapse
|
5
|
Geffroy S, Lechat MM, Le Gac M, Rovillon GA, Marie D, Bigeard E, Malo F, Amzil Z, Guillou L, Caruana AMN. From the sxtA4 Gene to Saxitoxin Production: What Controls the Variability Among Alexandrium minutum and Alexandrium pacificum Strains? Front Microbiol 2021; 12:613199. [PMID: 33717003 PMCID: PMC7944994 DOI: 10.3389/fmicb.2021.613199] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 02/03/2021] [Indexed: 12/22/2022] Open
Abstract
Paralytic shellfish poisoning (PSP) is a human foodborne syndrome caused by the consumption of shellfish that accumulate paralytic shellfish toxins (PSTs, saxitoxin group). In PST-producing dinoflagellates such as Alexandrium spp., toxin synthesis is encoded in the nuclear genome via a gene cluster (sxt). Toxin production is supposedly associated with the presence of a 4th domain in the sxtA gene (sxtA4), one of the core genes of the PST gene cluster. It is postulated that gene expression in dinoflagellates is partially constitutive, with both transcriptional and post-transcriptional processes potentially co-occurring. Therefore, gene structure and expression mode are two important features to explore in order to fully understand toxin production processes in dinoflagellates. In this study, we determined the intracellular toxin contents of twenty European Alexandrium minutum and Alexandrium pacificum strains that we compared with their genome size and sxtA4 gene copy numbers. We observed a significant correlation between the sxtA4 gene copy number and toxin content, as well as a moderate positive correlation between the sxtA4 gene copy number and genome size. The 18 toxic strains had several sxtA4 gene copies (9-187), whereas only one copy was found in the two observed non-toxin producing strains. Exploration of allelic frequencies and expression of sxtA4 mRNA in 11 A. minutum strains showed both a differential expression and specific allelic forms in the non-toxic strains compared with the toxic ones. Also, the toxic strains exhibited a polymorphic sxtA4 mRNA sequence between strains and between gene copies within strains. Finally, our study supported the hypothesis of a genetic determinism of toxin synthesis (i.e., the existence of several genetic isoforms of the sxtA4 gene and their copy numbers), and was also consistent with the hypothesis that constitutive gene expression and moderation by transcriptional and post-transcriptional regulation mechanisms are the cause of the observed variability in the production of toxins by A. minutum.
Collapse
Affiliation(s)
| | | | | | | | - Dominique Marie
- Sorbonne Université, CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
| | - Estelle Bigeard
- Sorbonne Université, CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
| | | | | | - Laure Guillou
- Sorbonne Université, CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
| | | |
Collapse
|
6
|
Bowazolo C, Tse SPK, Beauchemin M, Lo SCL, Rivoal J, Morse D. Label-free MS/MS analyses of the dinoflagellate Lingulodinium identifies rhythmic proteins facilitating adaptation to a diurnal LD cycle. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 704:135430. [PMID: 31818571 DOI: 10.1016/j.scitotenv.2019.135430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/01/2019] [Accepted: 11/06/2019] [Indexed: 06/10/2023]
Abstract
Protein levels were assessed in the dinoflagellate Lingulodinium polyedra over the course of a diurnal cycle using a label-free LC-MS/MS approach. Roughly 1700 proteins were quantitated in a triplicate dataset over a daily period, and 13 were found to show significant rhythmic changes. Included among the proteins found to be most abundant at night were the two bioluminescence proteins, luciferase and luciferin binding protein, as well as a proliferating cell nuclear protein involved in the nightly DNA replication. Aconitase and a pyrophosphate fructose-6-phosphate-1-phosphotransferase were also found to be more abundant at night, suggestive of an increased ability to generate ATP by glucose catabolism when photosynthesis does not occur. Among the proteins more abundant during the day were found a 2-epi-5-epi-valiolone synthase, potentially involved in synthesis of mycosporin-like amino acids that can act as a "microbial sunscreen", and an enzyme synthesizing vitamin B6 which is known to protect against oxidative stress. A lactate oxidoreductase was also found to be more abundant during the day, perhaps to counteract the pH changes due to carbon fixation by facilitating conversion of pyruvate to lactate. This unbiased proteomic approach reveals novel insights into the daily metabolic changes of this dinoflagellate. Furthermore, the observation that only a limited number of proteins vary support a model where metabolic flux through pathways can be controlled by variations in a select few, possibly rate limiting, steps. Data are available via ProteomeXchange with identifier PXD006994.
Collapse
Affiliation(s)
- Carl Bowazolo
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Canada
| | - Sirius P K Tse
- Shenzhen Key Laboratory of Food Biological Safety Control, Department of Applied Biology and Chemical Technology, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Mathieu Beauchemin
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Canada
| | - Samuel C-L Lo
- Shenzhen Key Laboratory of Food Biological Safety Control, Department of Applied Biology and Chemical Technology, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Jean Rivoal
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Canada
| | - David Morse
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Canada
| |
Collapse
|
7
|
Akbar MA, Mohd Yusof NY, Tahir NI, Ahmad A, Usup G, Sahrani FK, Bunawan H. Biosynthesis of Saxitoxin in Marine Dinoflagellates: An Omics Perspective. Mar Drugs 2020; 18:md18020103. [PMID: 32033403 PMCID: PMC7073992 DOI: 10.3390/md18020103] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/09/2020] [Accepted: 01/09/2020] [Indexed: 02/07/2023] Open
Abstract
Saxitoxin is an alkaloid neurotoxin originally isolated from the clam Saxidomus giganteus in 1957. This group of neurotoxins is produced by several species of freshwater cyanobacteria and marine dinoflagellates. The saxitoxin biosynthesis pathway was described for the first time in the 1980s and, since then, it was studied in more than seven cyanobacterial genera, comprising 26 genes that form a cluster ranging from 25.7 kb to 35 kb in sequence length. Due to the complexity of the genomic landscape, saxitoxin biosynthesis in dinoflagellates remains unknown. In order to reveal and understand the dynamics of the activity in such impressive unicellular organisms with a complex genome, a strategy that can carefully engage them in a systems view is necessary. Advances in omics technology (the collective tools of biological sciences) facilitated high-throughput studies of the genome, transcriptome, proteome, and metabolome of dinoflagellates. The omics approach was utilized to address saxitoxin-producing dinoflagellates in response to environmental stresses to improve understanding of dinoflagellates gene–environment interactions. Therefore, in this review, the progress in understanding dinoflagellate saxitoxin biosynthesis using an omics approach is emphasized. Further potential applications of metabolomics and genomics to unravel novel insights into saxitoxin biosynthesis in dinoflagellates are also reviewed.
Collapse
Affiliation(s)
- Muhamad Afiq Akbar
- School of Bioscience and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia;
| | - Nurul Yuziana Mohd Yusof
- Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia; (N.Y.M.Y.); (F.K.S.)
| | - Noor Idayu Tahir
- Malaysian Palm Oil Board, No 6, Persiaran Institusi, Bandar Baru Bangi, Kajang 43000, Selangor, Malaysia;
| | - Asmat Ahmad
- University College Sabah Foundation, Jalan Sanzac, Kota Kinabalu 88100, Sabah, Malaysia; (A.A.); (G.U.)
| | - Gires Usup
- University College Sabah Foundation, Jalan Sanzac, Kota Kinabalu 88100, Sabah, Malaysia; (A.A.); (G.U.)
| | - Fathul Karim Sahrani
- Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia; (N.Y.M.Y.); (F.K.S.)
| | - Hamidun Bunawan
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia
- Correspondence: ; Tel.: +60-389-214-546
| |
Collapse
|
8
|
Wang X, Niu X, Chen Y, Sun Z, Han A, Lou X, Ge J, Li X, Yang Y, Jian J, Gonçalves RJ, Guan W. Transcriptome sequencing of a toxic dinoflagellate, Karenia mikimotoi subjected to stress from solar ultraviolet radiation. HARMFUL ALGAE 2019; 88:101640. [PMID: 31582153 DOI: 10.1016/j.hal.2019.101640] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
Solar ultraviolet radiation (UVR) is a stress factor in aquatic environments and may act directly or indirectly on orgnisms in the upper layers of the water column. However, UVR effects are usually species-specific and difficult to extrapolate. Here we use the HAB-forming, toxic dinoflagellate Karenia mikimotoi (which was found to be relatively resistant in previous studies) to investigate its transcriptional responses to a one-week UVR exposure. For this, batch cultures of K. mikimotoi were grown with and without UVR, and their transcriptomes (generated via RNAseq technology) were compared. RNA-seq generated 45.31 million reads, which were further assembled to 202600 unigenes (>300bp). Among these, ca. 61% were annotated with NCBI, NR, GO, KOG, PFAM, Swiss-Prot, and KEGG database. Transcriptomic analysis revealed 722 differentially expressed unigenes (DEGs, defined as being within a |log2 fold change| ≥ 2 and padj < 0.05) responding to solar UVR, which were only 0.36% of all unigenes. 716 unigenes were down-regulated, and only 6 unigenes were up-regulated in the UVR compared to non-UVR treatment. KEGG pathway further analysis revealed DEGs were involved in the different pathway; genes involved in the ribosome, endocytosis and steroid biosynthesis pathways were highly down-regulated, but this was not the case for those involved in the energy metabolisms (including photosynthesis, oxidative phosphorylation) which may contribute to the sustainable growth observed in UVR treatment. The up-regulated expression of both zinc-finger proteins (ZFPs) and ribosomal protein L11 (RPL11) may be one of the acclimated mechanisms against UVR. In addition, this work identified down-regulated genes involved in fatty acid degradation and the hydrophobic branched chain amino acids (e.g., Valine, leucine, and isoleucine), which act as structural components of cell membranes modulating lipid homeostasis or turnover. In conclusion, the present study suggests that the toxic dinoflagellate K. mikimotoi has limited transcriptomic regulation but confirms that it appears as a tolerant species in response to solar UVR. These findings expand current knowledge of gene expression in HAB-forming species in response to natural environment factors such as solar radiation.
Collapse
Affiliation(s)
- Xinjie Wang
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China; Marine Biology Institute, Shantou University, Shantou, Guangdong 515063 China
| | - Xiaoqin Niu
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Yiji Chen
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Zhewei Sun
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Axiang Han
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Xiayuan Lou
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Jingke Ge
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Xuanwen Li
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Yuqian Yang
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Jianbo Jian
- Marine Biology Institute, Shantou University, Shantou, Guangdong 515063 China
| | - Rodrigo J Gonçalves
- Laboratorio de Oceanografía Biológica (LOBio), Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). U9120ACD, Puerto Madryn, Argentina
| | - Wanchun Guan
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China.
| |
Collapse
|
9
|
Wang H, Kim H, Lim WA, Ki JS. Molecular cloning and oxidative-stress responses of a novel manganese superoxide dismutase (MnSOD) gene in the dinoflagellate Prorocentrum minimum. Mol Biol Rep 2019; 46:5955-5966. [PMID: 31407247 DOI: 10.1007/s11033-019-05029-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 08/07/2019] [Indexed: 10/26/2022]
Abstract
Dinoflagellate algae are microeukaryotes that have distinct genomes and gene regulation systems, making them an interesting model for studying protist evolution and genomics. In the present study, we discovered a novel manganese superoxide dismutase (PmMnSOD) gene from the marine dinoflagellate Prorocentrum minimum, examined its molecular characteristics, and evaluated its transcriptional responses to the oxidative stress-inducing contaminants, CuSO4 and NaOCl. Its cDNA was 1238 bp and contained a dinoflagellate spliced leader sequence, a 906 bp open reading frame (301 amino acids), and a poly (A) tail. The gene was coded on the nuclear genome with one 174 bp intron; signal peptide analysis showed that it might be localized to the mitochondria. Real-time PCR analysis revealed an increase in gene expression of MnSOD and SOD activity when P. minimum cells were separately exposed to CuSO4 and NaOCl. In addition, both contaminants considerably decreased chlorophyll autofluorescence, and increased intracellular reactive oxygen species. These results suggest that dinoflagellate MnSOD may be involved in protecting cells against oxidative damage.
Collapse
Affiliation(s)
- Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea
| | - Hansol Kim
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea
| | - Weol-Ae Lim
- Ocean Climate and Ecology Research Division, National Institute of Fisheries Science (NIFS), Busan, 46083, South Korea
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea.
| |
Collapse
|
10
|
Zhang H, Liu J, He Y, Xie Z, Zhang S, Zhang Y, Lin L, Liu S, Wang D. Quantitative proteomics reveals the key molecular events occurring at different cell cycle phases of the in situ blooming dinoflagellate cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 676:62-71. [PMID: 31029901 DOI: 10.1016/j.scitotenv.2019.04.216] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/01/2019] [Accepted: 04/13/2019] [Indexed: 05/26/2023]
Abstract
Dinoflagellate blooms are the results of rapid cell proliferation governed by cell cycle, a highly-ordered series of events that culminates in cell division. However, little is known about cell cycle progression of the in situ bloom cells. Here, we compared proteomes of the in situ blooming cells of a dinoflagellate Prorocentrum donghaiense collected at different cell cycle phases. The blooming P. donghaiense cells completed a cell cycle within 24 h with a high synchronization rate of 82.7%. Proteins associated with photosynthesis, porphyrin and chlorophyll synthesis, carbon, nitrogen and amino acid metabolisms exhibited high expressions at the G1 phase; DNA replication and mismatch repair related proteins were more abundant at the S phase; while protein synthesis and oxidative phosphorylation were highly enriched at the G2/M phase. Cell cycle proteins presented similar periodic diel patterns to other eukaryotic cells, and higher expressions of proliferating cell nuclear antigen and cyclin dependent kinase 2 at the S phase ensured the smooth S-G2/M transition. Strikingly, four histones were first identified in P. donghaiense and highly expressed at the G2/M phase, indicating their potential roles in regulating cell cycle. This study presents the first quantitative survey, to our knowledge, of proteome changes at different cell cycle phases of the in situ blooming cells in natural environment and provides insights into cell cycle regulation of the blooming dinoflagellate cells.
Collapse
Affiliation(s)
- Hao Zhang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361005, China
| | - Jiuling Liu
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361005, China; Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Yanbin He
- BGI-Shenzhen, Beishan Industrial Zone 11th building, Yantian District, Shenzhen, Guangdong 518083, China
| | - Zhangxian Xie
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361005, China
| | - Shufei Zhang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361005, China; South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Yong Zhang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361005, China
| | - Lin Lin
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361005, China
| | - Siqi Liu
- BGI-Shenzhen, Beishan Industrial Zone 11th building, Yantian District, Shenzhen, Guangdong 518083, China
| | - Dazhi Wang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361005, China.
| |
Collapse
|
11
|
Verma A, Barua A, Ruvindy R, Savela H, Ajani PA, Murray SA. The Genetic Basis of Toxin Biosynthesis in Dinoflagellates. Microorganisms 2019; 7:E222. [PMID: 31362398 PMCID: PMC6722697 DOI: 10.3390/microorganisms7080222] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/23/2019] [Accepted: 07/27/2019] [Indexed: 02/07/2023] Open
Abstract
In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth rates. One factor that may play a role in their ecological success is the production of complex secondary metabolite compounds that can have anti-predator, allelopathic, or other toxic effects on marine organisms, and also cause seafood poisoning in humans. Our knowledge about the genes involved in toxin biosynthesis in dinoflagellates is currently limited due to the complex genomic features of these organisms. Most recently, the sequencing of dinoflagellate transcriptomes has provided us with valuable insights into the biosynthesis of polyketide and alkaloid-based toxin molecules in dinoflagellate species. This review synthesizes the recent progress that has been made in understanding the evolution, biosynthetic pathways, and gene regulation in dinoflagellates with the aid of transcriptomic and other molecular genetic tools, and provides a pathway for future studies of dinoflagellates in this exciting omics era.
Collapse
Affiliation(s)
- Arjun Verma
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia.
| | - Abanti Barua
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
- Department of Microbiology, Noakhali Science and Technology University, Chittagong 3814, Bangladesh
| | - Rendy Ruvindy
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
| | - Henna Savela
- Finnish Environment Institute, Marine Research Centre, 00790 Helsinki, Finland
| | - Penelope A Ajani
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
| | - Shauna A Murray
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
| |
Collapse
|
12
|
Diel transcriptional response of a California Current plankton microbiome to light, low iron, and enduring viral infection. ISME JOURNAL 2019; 13:2817-2833. [PMID: 31320727 PMCID: PMC6794264 DOI: 10.1038/s41396-019-0472-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 06/11/2019] [Accepted: 06/15/2019] [Indexed: 01/06/2023]
Abstract
Phytoplankton and associated microbial communities provide organic carbon to oceanic food webs and drive ecosystem dynamics. However, capturing those dynamics is challenging. Here, an in situ, semi-Lagrangian, robotic sampler profiled pelagic microbes at 4 h intervals over ~2.6 days in North Pacific high-nutrient, low-chlorophyll waters. We report on the community structure and transcriptional dynamics of microbes in an operationally large size class (>5 μm) predominantly populated by dinoflagellates, ciliates, haptophytes, pelagophytes, diatoms, cyanobacteria (chiefly Synechococcus), prasinophytes (chiefly Ostreococcus), fungi, archaea, and proteobacteria. Apart from fungi and archaea, all groups exhibited 24-h periodicity in some transcripts, but larger portions of the transcriptome oscillated in phototrophs. Periodic photosynthesis-related transcripts exhibited a temporal cascade across the morning hours, conserved across diverse phototrophic lineages. Pronounced silica:nitrate drawdown, a high flavodoxin to ferredoxin transcript ratio, and elevated expression of other Fe-stress markers indicated Fe-limitation. Fe-stress markers peaked during a photoperiodically adaptive time window that could modulate phytoplankton response to seasonal Fe-limitation. Remarkably, we observed viruses that infect the majority of abundant taxa, often with total transcriptional activity synchronized with putative hosts. Taken together, these data reveal a microbial plankton community that is shaped by recycled production and tightly controlled by Fe-limitation and viral activity.
Collapse
|
13
|
Morse D, Tse SPK, Lo SCL. Exploring dinoflagellate biology with high-throughput proteomics. HARMFUL ALGAE 2018; 75:16-26. [PMID: 29778222 DOI: 10.1016/j.hal.2018.03.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 03/27/2018] [Accepted: 03/28/2018] [Indexed: 06/08/2023]
Abstract
Dinoflagellates are notorious for their ability to form the harmful algal blooms known as "red tides," yet the mechanisms underlying bloom formation remain poorly understood. Despite recent advances in nucleic acid sequencing, which have generated transcriptomes from a wide range of species exposed to a variety of different conditions, measuring changes in RNA levels have not generally produced great insight into dinoflagellate cell biology or environmental physiology, nor do we have a thorough grasp on the molecular events underpinning bloom formation. Not only is the transcriptomic response of dinoflagellates to environmental change generally muted, but there is a markedly low degree of congruency between mRNA expression and protein expression in dinoflagellates. Herein we discuss the application of high-throughput proteomics to the study of dinoflagellate biology. By profiling the cellular protein complement (the proteome) instead of mRNA (the transcriptome), the biomolecular events that underlie the changes of phenotypes can be more readily evaluated, as proteins directly determine the structure and the function of the cell. Recent advances in proteomics have seen this technique become a high-throughput method that is now able to provide a perspective different from the more commonly employed nucleic acid sequencing. We suggest that the time is ripe to exploit these new technologies in addressing the many mysteries of dinoflagellate biology, such as how the symbiotic dinoflagellate inhabiting reef corals acclimate to increases in temperature, as well as how harmful algal blooms are initiated at the sub-cellular level. Furthermore, as dinoflagellates are not the only eukaryotes that demonstrate muted transcriptional responses, the techniques addressed within this review are amenable to a wide array of organisms.
Collapse
Affiliation(s)
- David Morse
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Canada.
| | - Sirius P K Tse
- Shenzhen Key Laboratory of Food Biological Safety Control, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong
| | - Samuel C L Lo
- Shenzhen Key Laboratory of Food Biological Safety Control, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong
| |
Collapse
|
14
|
Roy S, Jagus R, Morse D. Translation and Translational Control in Dinoflagellates. Microorganisms 2018; 6:microorganisms6020030. [PMID: 29642465 PMCID: PMC6027434 DOI: 10.3390/microorganisms6020030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 12/24/2022] Open
Abstract
Dinoflagellates are unicellular protists that feature a multitude of unusual nuclear features, including large genomes, packaging of DNA without histones, and multiple gene copies organized as tandem gene arrays. Furthermore, all dinoflagellate mRNAs experience trans-splicing with a common 22-nucleotide splice leader (SL) sequence. These features challenge some of the concepts and assumptions about the regulation of gene expression derived from work on model eukaryotes such as yeasts and mammals. Translational control in the dinoflagellates, based on extensive study of circadian bioluminescence and by more recent microarray and transcriptome analyses, is now understood to be a crucial element in regulating gene expression. A picture of the translation machinery of dinoflagellates is emerging from the recent availability of transcriptomes of multiple dinoflagellate species and the first complete genome sequences. The components comprising the translational control toolkit of dinoflagellates are beginning to take shape and are outlined here.
Collapse
Affiliation(s)
- Sougata Roy
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke East, Montréal, QC H1X 2B2, Canada.
| | - Rosemary Jagus
- Institute of Marine & Environmental Technology, University of Maryland Center for Environmental Science701 E. Pratt St., Baltimore, MD 21202, USA.
| | - David Morse
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke East, Montréal, QC H1X 2B2, Canada.
| |
Collapse
|
15
|
Zhang SF, Zhang Y, Lin L, Wang DZ. iTRAQ-Based Quantitative Proteomic Analysis of a Toxigenic Dinoflagellate Alexandrium catenella and Its Non-toxigenic Mutant Exposed to a Cell Cycle Inhibitor Colchicine. Front Microbiol 2018; 9:650. [PMID: 29670604 PMCID: PMC5893714 DOI: 10.3389/fmicb.2018.00650] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 03/20/2018] [Indexed: 12/22/2022] Open
Abstract
Paralytic shellfish toxins (PSTs) are a group of potent neurotoxic alkaloids mainly produced by marine dinoflagellates and their biosynthesis is associated with the cell cycle. Study shows that colchicine can cease cell division and inhibit PST production of dinoflagellates. However, the molecular mechanism behind this linkage is unknown. Here, we applied the iTRAQ-based proteomic approach to investigate protein expression profiles of a toxigenic dinoflagellate Alexandrium catenella (ACHK-T) and its non-toxigenic mutant (ACHK-NT) when treated with colchicine. The results showed that the cell cycles of both strains were arrested at the G1 phase by colchicine, and the toxin biosynthesis of ACHK-T was inhibited. Among 6,988 proteins identified, 113 and 253 proteins were differentially expressed in the colchicine-treated ACHK-T and ACHK-NT, respectively, compared with their non-colchicine treatments. Proteins involved in reactive oxygen species scavenging and protein degradation were upregulated in both strains while proteins participating in photosynthetic pigment biosynthesis and nitrogen metabolism presented different expressions. Nitrate reductase and glutamine synthetase were altered insignificantly in the colchicine-treated ACHK-T while both of them were remarkably downregulated in the colchicine-treated ACHK-NT, suggesting a feedback regulation between PST production and nitrogen metabolism in ACHK-T. Nitrogen originally for PST biosynthesis might be reallocated to photosynthetic pigment biosynthesis in the colchicine-treated ACHK-T. A total of 55 homologs of 7 toxin-related proteins were obtained; however, they altered insignificantly in both colchicine-treated strains, suggesting that toxin biosynthesis might be post-translationally regulated. Our study provided new insights into toxin biosynthesis in marine dinoflagellates.
Collapse
Affiliation(s)
- Shu-Fei Zhang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, China
- Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Yong Zhang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, China
| | - Lin Lin
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, China
| | - Da-Zhi Wang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, China
| |
Collapse
|
16
|
CpMCA , a novel metacaspase gene from the harmful dinoflagellate Cochlodinium polykrikoides and its expression during cell death. Gene 2018; 651:70-78. [DOI: 10.1016/j.gene.2018.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/26/2018] [Accepted: 02/01/2018] [Indexed: 11/23/2022]
|
17
|
Wang H, Guo R, Ki JS. 6.0 K microarray reveals differential transcriptomic responses in the dinoflagellate Prorocentrum minimum exposed to polychlorinated biphenyl (PCB). CHEMOSPHERE 2018; 195:398-409. [PMID: 29274579 DOI: 10.1016/j.chemosphere.2017.12.066] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 10/23/2017] [Accepted: 12/11/2017] [Indexed: 06/07/2023]
Abstract
Endocrine disrupting chemicals (EDCs) have toxic effects on algae; however, their molecular genomic responses have not been sufficiently elucidated. Here, we evaluated genome-scaled responses of the dinoflagellate alga Prorocentrum minimum exposed to an EDC, polychlorinated biphenyl (PCB), using a 6.0 K microarray. Based on two-fold change cut-off, we identified that 609 genes (∼10.2%) responded to the PCB treatment. KEGG pathway analysis showed that differentially expressed genes (DEGs) were related to ribosomes, biosynthesis of amino acids, spliceosomes, and cellular processes. Many DEGs were involved in cell cycle progression, apoptosis, signal transduction, ion binding, and cellular transportation. In contrast, only a few genes related to photosynthesis and oxidative stress were expressed in response to PCB exposure. This was supported by that fact that there were no obvious changes in the photosynthetic efficiency and reactive oxygen species (ROS) production. These results suggest that PCB might not cause chloroplast and oxidative damage, but could lead to cell cycle arrest and apoptosis. In addition, various signal transduction and transport pathways might be disrupted in the cells, which could further contribute to cell death. These results expand the genomic understanding of the effects of EDCs on this dinoflagellate protist.
Collapse
Affiliation(s)
- Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Ruoyu Guo
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea.
| |
Collapse
|
18
|
Current Knowledge and Recent Advances in Marine Dinoflagellate Transcriptomic Research. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2018. [DOI: 10.3390/jmse6010013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
19
|
RNA-Seq as an Emerging Tool for Marine Dinoflagellate Transcriptome Analysis: Process and Challenges. Processes (Basel) 2018. [DOI: 10.3390/pr6010005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
|
20
|
Deng Y, Hu Z, Shang L, Peng Q, Tang YZ. Transcriptomic Analyses of Scrippsiella trochoidea Reveals Processes Regulating Encystment and Dormancy in the Life Cycle of a Dinoflagellate, with a Particular Attention to the Role of Abscisic Acid. Front Microbiol 2017; 8:2450. [PMID: 29312167 PMCID: PMC5732363 DOI: 10.3389/fmicb.2017.02450] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/27/2017] [Indexed: 12/26/2022] Open
Abstract
Due to the vital importance of resting cysts in the biology and ecology of many dinoflagellates, a transcriptomic investigation on Scrippsiella trochoidea was conducted with the aim to reveal the molecular processes and relevant functional genes regulating encystment and dormancy in dinoflagellates. We identified via RNA-seq 3,874 (out of 166,575) differentially expressed genes (DEGs) between resting cysts and vegetative cells; a pause of photosynthesis (confirmed via direct measurement of photosynthetic efficiency); an active catabolism including β-oxidation, glycolysis, glyoxylate pathway, and TCA in resting cysts (tested via measurements of respiration rate); 12 DEGs encoding meiotic recombination proteins and members of MEI2-like family potentially involved in sexual reproduction and encystment; elevated expressions in genes encoding enzymes responding to pathogens (chitin deacetylase) and ROS stress in cysts; and 134 unigenes specifically expressed in cysts. We paid particular attention to genes pertaining to phytohormone signaling and identified 4 key genes regulating abscisic acid (ABA) biosynthesis and catabolism, with further characterization based on their full-length cDNA obtained via RACE-PCR. The qPCR results demonstrated elevated biosynthesis and repressed catabolism of ABA during the courses of encystment and cyst dormancy, which was significantly enhanced by lower temperature (4 ± 1°C) and darkness. Direct measurements of ABA using UHPLC-MS/MS and ELISA in vegetative cells and cysts both fully supported qPCR results. These results collectively suggest a vital role of ABA in regulating encystment and maintenance of dormancy, akin to its function in seed dormancy of higher plants. Our results provided a critical advancement in understanding molecular processes in resting cysts of dinoflagellates.
Collapse
Affiliation(s)
- Yunyan Deng
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhangxi Hu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Lixia Shang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Quancai Peng
- Research Center of Analysis and Measurement, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Ying Zhong Tang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| |
Collapse
|
21
|
A Novel Cyclophilin B Gene in the Red Tide Dinoflagellate Cochlodinium polykrikoides: Molecular Characterizations and Transcriptional Responses to Environmental Stresses. BIOMED RESEARCH INTERNATIONAL 2017; 2017:4101580. [PMID: 29226135 PMCID: PMC5684524 DOI: 10.1155/2017/4101580] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 09/13/2017] [Indexed: 11/25/2022]
Abstract
The marine dinoflagellate Cochlodinium polykrikoides is one of the most common ichthyotoxic species that causes harmful algal blooms (HABs), which leads to ecological damage and huge economic loss in aquaculture industries. Cyclophilins (CYPs) belong to the immunophilin superfamily, and they may play a role in the survival mechanisms of the dinoflagellate in stress environments. In the present study, we identified a novel cyclophilin gene from C. polykrikoides and examined physiological and gene transcriptional responses to biocides copper sulphate (CuSO4) and sodium hypochlorite (NaOCl). The full length of CpCYP was 903 bp, ranging from the dinoflagellate splice leader (DinoSL) sequence to the polyA tail, comprising a 639 bp ORF, a 117 bp 5′-UTR, and a 147 bp 3′-UTR. Motif and phylogenetic comparisons showed that CpCYP was affiliated to group B of CYP. In biocide stressors, cell counts, chlorophyll a, and photosynthetic efficiency (Fv/Fm) of C. polykrikoides were considerably decreased in both exposure time- and dose-dependent manners. In addition, CpCYP gene expression was significantly induced after 24 h exposure to the biocide-treated stress conditions. These results indicate an effect of the biocides on the cell physiology and expression profile of CpCYP, suggesting that the gene may play a role in environmental stress responses.
Collapse
|
22
|
A proteomic portrait of dinoflagellate chromatin reveals abundant RNA-binding proteins. Chromosoma 2017; 127:29-43. [PMID: 28852823 DOI: 10.1007/s00412-017-0643-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 08/09/2017] [Accepted: 08/11/2017] [Indexed: 12/20/2022]
Abstract
Dinoflagellate chromatin is unique among eukaryotes, as the chromosomes are permanently condensed in a liquid crystal state instead of being packed in nucleosomes. However, how it is organized is still an unsolved mystery, in part due to the lack of a comprehensive catalog of dinoflagellate nuclear proteins. Here, we report the results of CHromatin Enrichment for Proteomics (CHEP) followed by shotgun mass spectrometry sequencing of the chromatin-associated proteins from the dinoflagellate Lingulodinum polyedra. Our analysis identified proteins involved in DNA replication and repair, transcription, and mRNA splicing, and showed a low level of contamination by proteins from other organelles. A limited number of proteins containing DNA-binding domains were found, consistent with the lack of diversity of these proteins in dinoflagellate transcriptomes. However, the number of proteins containing RNA-binding domains was unexpectedly high supporting a potential role for this type of protein in mediating gene expression and chromatin organization. We also identified a number of proteins involved in chromosome condensation and cell cycle progression as well as a single histone protein (H4). Our results provide the first detailed look at the nuclear proteins associated with the unusual chromatin structure of dinoflagellate nuclei and provide important insights into the biochemical basis of its structure and function.
Collapse
|
23
|
Matantseva O, Skarlato S, Vogts A, Pozdnyakov I, Liskow I, Schubert H, Voss M. Superposition of Individual Activities: Urea-Mediated Suppression of Nitrate Uptake in the Dinoflagellate Prorocentrum minimum Revealed at the Population and Single-Cell Levels. Front Microbiol 2016; 7:1310. [PMID: 27610101 PMCID: PMC4996987 DOI: 10.3389/fmicb.2016.01310] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 08/08/2016] [Indexed: 12/23/2022] Open
Abstract
Dinoflagellates readily use diverse inorganic and organic compounds as nitrogen sources, which is advantageous in eutrophied coastal areas exposed to high loads of anthropogenic nutrients, e.g., urea, one of the most abundant organic nitrogen substrates in seawater. Cell-to-cell variability in nutritional physiology can further enhance the diversity of metabolic strategies among dinoflagellates of the same species, but it has not been studied in free-living microalgae. We applied stable isotope tracers, isotope ratio mass spectrometry and nanoscale secondary ion mass spectrometry (NanoSIMS) to investigate the response of cultured nitrate-acclimated dinoflagellates Prorocentrum minimum to a sudden input of urea and the effect of urea on the concurrent nitrate uptake at the population and single-cell levels. We demonstrate that inputs of urea lead to suppression of nitrate uptake by P. minimum, and urea uptake exceeds the concurrent uptake of nitrate. Individual dinoflagellate cells within a population display significant heterogeneity in the rates of nutrient uptake and extent of the urea-mediated inhibition of the nitrate uptake, thus forming several groups characterized by different modes of nutrition. We conclude that urea originating from sporadic sources is rapidly utilized by dinoflagellates and can be used in biosynthesis or stored intracellularly depending on the nutrient status; therefore, sudden urea inputs can represent one of the factors triggering or supporting harmful algal blooms. Significant physiological heterogeneity revealed at the single-cell level is likely to play a role in alleviation of intra-population competition for resources and can affect the dynamics of phytoplankton populations and their maintenance in natural environments.
Collapse
Affiliation(s)
- Olga Matantseva
- Institute of Cytology, Russian Academy of Sciences St. Petersburg, Russia
| | - Sergei Skarlato
- Institute of Cytology, Russian Academy of Sciences St. Petersburg, Russia
| | - Angela Vogts
- Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany
| | - Ilya Pozdnyakov
- Institute of Cytology, Russian Academy of Sciences St. Petersburg, Russia
| | - Iris Liskow
- Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany
| | - Hendrik Schubert
- Institute of Biological Sciences, University of Rostock Rostock, Germany
| | - Maren Voss
- Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany
| |
Collapse
|
24
|
Ryan DE, Campbell L. Identification and phylogeny of putative PEPC genes in three toxin-producing Karenia (Dinophyta) species. JOURNAL OF PHYCOLOGY 2016; 52:618-625. [PMID: 27136041 DOI: 10.1111/jpy.12423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 02/17/2016] [Indexed: 06/05/2023]
Abstract
Dense blooms of toxin-producing Karenia brevis increase local surface ocean pH through CO2 uptake. To identify genes that may contribute to bloom-related environmental pH and pCO2 changes, transcriptomes with RNA from K. brevis Wilson cultures that had been acclimated to low CO2 (250 ppm) or recent CO2 (350 ppm) pCO2 levels were assembled. Among the annotated transcripts were PEPC, PPDK, and PEPCK enzymes found in the model C4 carbon fixation pathway. Previous studies have demonstrated that the enzymatic activity of PEPC, PPDK, and/or PEPCK in some algae species, including marine diatoms, is influenced by variations in dissolved inorganic carbon. We found significantly similar PEPC, PPDK, and PEPCK enzymes in the transcriptomes of K. brevis and two sister species Karenia papilionacea, and Karenia mikimotoi. One or more isoforms of PEPC were also identified in the transcriptomes of thirty additional photosynthetic phytoplankton species from nine phyla. Phylogenetic trees were constructed with neighbor joining and maximum likelihood techniques to characterize the evolutionary relationship among phytoplankton, terrestrial plant C4, and terrestrial plant C3 PEPC sequences. Based on the nucleotide trees constructed during this study, the Karenia PEPC transcripts were more closely related to the terrestrial C4 genes than the terrestrial C3 genes. Furthermore, PEPC phylogeny among phytoplankton closely resembles phylogenetic trees constructed with ribosomal RNA. This study confirmed that the toxin-producing dinoflagellates K. brevis, K. mikimotoi, and K. papilionacea express putative PEPC, PEPCK, and PPDK transcripts.
Collapse
Affiliation(s)
- Darcie E Ryan
- Department of Oceanography, Texas A & M University, College Station, Texas, 77843, USA
| | - Lisa Campbell
- Department of Oceanography, Texas A & M University, College Station, Texas, 77843, USA
- Department of Oceanography and Department of Biology, Texas A & M University, College Station, Texas, 77843, USA
| |
Collapse
|
25
|
Guo R, Lim WA, Ki JS. Genome-wide analysis of transcription and photosynthesis inhibition in the harmful dinoflagellate Prorocentrum minimum in response to the biocide copper sulfate. HARMFUL ALGAE 2016; 57:27-38. [PMID: 30170719 DOI: 10.1016/j.hal.2016.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 06/08/2023]
Abstract
Copper is an essential trace metal for organisms; however, excess copper may damage cellular processes. Their efficiency and physiological effects of biocides have been well documented; however, molecular transcriptome responses to biocides are insufficiently studied. In the present study, a 6.0K oligonucleotide chip was developed to investigate the molecular responses of the harmful dinoflagellate Prorocentrum minimum to copper sulfate (CuSO4) treatment. The results revealed that 515 genes (approximately 8.6%) responded to CuSO4, defined as being within a 2-fold change. Further, KEGG pathway analysis showed that differentially expressed genes (DEGs) were involved in ribosomal function, RNA transport, carbon metabolism, biosynthesis of amino acids, photosystem maintenance, and other cellular processes. Among the DEGs, 49 genes were related to chloroplasts and mitochondria. Furthermore, the genes involved in the RAS signaling pathway, MAPK signaling pathway, and transport pathways were identified. An additional experiment showed that the photosynthesis efficiency decreased considerably, and reactive oxygen species (ROS) production increased in P. minimum after CuSO4 exposure. These results suggest that CuSO4 caused cellular oxidative stress in P. minimum, affecting the ribosome and mitochondria, and severely damaged the photosystem. These effects may potentially lead to cell death, although the dinoflagellate has developed a complex signal transduction process to combat copper toxicity.
Collapse
Affiliation(s)
- Ruoyu Guo
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, Republic of Korea
| | - Weol-Ae Lim
- Oceanic Climate & Ecology Research Division, the National Institute of Fisheries Science (NISF), Busan 46083, Republic of Korea
| | - Jang-Seu Ki
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, Republic of Korea.
| |
Collapse
|
26
|
Meek ME, Van Dolah FM. Phytoplankton IF-FISH: Species-specific labeling of cellular proteins by immunofluorescence (IF) with simultaneous species identification by fluorescence immunohybridization (FISH). J Microbiol Methods 2016; 124:21-7. [DOI: 10.1016/j.mimet.2016.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/28/2016] [Accepted: 02/29/2016] [Indexed: 12/24/2022]
|
27
|
Guo R, Wang H, Suh YS, Ki JS. Transcriptomic profiles reveal the genome-wide responses of the harmful dinoflagellate Cochlodinium polykrikoides when exposed to the algicide copper sulfate. BMC Genomics 2016; 17:29. [PMID: 26732698 PMCID: PMC4702327 DOI: 10.1186/s12864-015-2341-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 12/22/2015] [Indexed: 11/29/2022] Open
Abstract
Background Harmful algal blooms (HABs) caused by the dinoflagellate Cochlodinium polykrikoides lead to severe environmental impacts in oceans worldwide followed by huge economic losses. Algicide agent copper sulfate (CuSO4) is regard as an economical and effective agent for HABs mitigation; its biochemical and physiological effects were revealed in C. polykrikoides. However, molecular mechanisms of CuSO4 effect on the C. polykrikoides, even other HAB species, have not been investigated. The present study investigated the transcriptional response of C. polykrikoides against CuSO4 treatments, with the aim of providing certain molecular mechanism of CuSO4 effect on the C. polykrikoides blooms. Results RNA-seq generated 173 million reads, which were further assembled to 191,212 contigs. 43.3 %, 33.9 %, and 15.6 % of contigs were annotated with NCBI NR, GO, and KEGG database, respectively. Transcriptomic analysis revealed 20.6 % differential expressed contigs, which grouped into 8 clusters according to K-means clustering analysis, responding to CuSO4; 848 contigs were up-regulated and 746 contigs were down-regulated more than 2-fold changes from 12 h to 48 h exposure. KEGG pathway analysis of eukaryotic homologous genes revealed the differentially expressed genes (DEGs) were involved in diverse pathway; amongst, the genes involved in the translation, spliceosome, and/or signal transduction genes were highly regulated. Most of photosystem related genes were down-regulated and most of mitochondria related genes were up-regulated. In addition, the genes involved in the copper ion binding or transporting and antioxidant systems were identified. Measurement of chlorophyll fluorescence showed that photosynthesis was significantly inhibited by CuSO4 exposure. Conclusions This study reported the first transcriptome of the C. polykrikoides. The widely differential expressed photosystem genes suggested photosynthetic machinery were severely affected, and may further contribute to the cell death. Furthermore, gene translation and transcription processes may be disrupted, inhibiting cell growth and proliferation, and possibly accelerating cell death. However, antioxidant systems resistant to CuSO4 caused stress; mitochondrion may compensate for photosynthesis efficiency decreasing caused energy deficiency. In addition, various signal transduction pathways may be involved in the CuSO4 induced regulation network in the C. polykrikoides. These data provide the potential transcriptomic mechanism to explain the algicide CuSO4 effect on the harmful dinoflagellate C. polykrikoides. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2341-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ruoyu Guo
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul, 110-743, Korea.
| | - Hui Wang
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul, 110-743, Korea
| | - Young Sang Suh
- Fishery and Ocean Information Division, National Fisheries Research & Development Institute, Busan, 619-705, Korea.
| | - Jang-Seu Ki
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul, 110-743, Korea.
| |
Collapse
|
28
|
Wang DZ, Zhang SF, Zhang Y, Lin L. Paralytic shellfish toxin biosynthesis in cyanobacteria and dinoflagellates: A molecular overview. J Proteomics 2015; 135:132-140. [PMID: 26316331 DOI: 10.1016/j.jprot.2015.08.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 07/28/2015] [Accepted: 08/14/2015] [Indexed: 12/22/2022]
Abstract
UNLABELLED Paralytic shellfish toxins (PSTs) are a group of water soluble neurotoxic alkaloids produced by two different kingdoms of life, prokaryotic cyanobacteria and eukaryotic dinoflagellates. Owing to the wide distribution of these organisms, these toxic secondary metabolites account for paralytic shellfish poisonings around the world. On the other hand, their specific binding to voltage-gated sodium channels makes these toxins potentially useful in pharmacological and toxicological applications. Much effort has been devoted to the biosynthetic mechanism of PSTs, and gene clusters encoding 26 proteins involved in PST biosynthesis have been unveiled in several cyanobacterial species. Functional analysis of toxin genes indicates that PST biosynthesis in cyanobacteria is a complex process including biosynthesis, regulation, modification and export. However, less is known about the toxin biosynthesis in dinoflagellates owing to our poor understanding of the massive genome and unique chromosomal characteristics [1]. So far, few genes involved in PST biosynthesis have been identified from dinoflagellates. Moreover, the proteins involved in PST production are far from being totally explored. Thus, the origin and evolution of PST biosynthesis in these two kingdoms are still controversial. In this review, we summarize the recent progress on the characterization of genes and proteins involved in PST biosynthesis in cyanobacteria and dinoflagellates, and discuss the standing evolutionary hypotheses concerning the origin of toxin biosynthesis as well as future perspectives in PST biosynthesis. SCIENTIFIC QUESTION Paralytic shellfish toxins (PSTs) are a group of potent neurotoxins which specifically block voltage-gated sodium channels in excitable cells and result in paralytic shellfish poisonings (PSPs) around the world. Two different kingdoms of life, cyanobacteria and dinoflagellates are able to produce PSTs. However, in contrast with cyanobacteria, our understanding of PST biosynthesis in dinoflagellates is extremely limited owing to their unique features. The origin and evolution of PST biosynthesis in these two kingdoms are still controversial. TECHNICAL SIGNIFICANCE High-throughput omics technologies, such as genomics, transcriptomics and proteomics provide powerful tools for the study of PST biosynthesis in cyanobacteria and dinoflagellates, and have shown their powerful potential with regard to revealing genes and proteins involved in PST biosynthesis in two kingdoms. SCIENTIFIC SIGNIFICANCE This review summarizes the recent progress in PST biosynthesis in cyanobacteria and dinoflagellates with focusing on the novel insights from omics technologies, and discusses the evolutionary relationship of toxin biosynthesis genes between these two kingdoms.
Collapse
Affiliation(s)
- Da-Zhi Wang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China.
| | - Shu-Fei Zhang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen 361005, China
| | - Yong 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
| |
Collapse
|
29
|
Wiese M, Murray SA, Alvin A, Neilan BA. Gene expression and molecular evolution of sxtA4 in a saxitoxin producing dinoflagellate Alexandrium catenella. Toxicon 2014; 92:102-12. [PMID: 25301480 DOI: 10.1016/j.toxicon.2014.09.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 09/25/2014] [Indexed: 10/24/2022]
Abstract
Dinoflagellates of the genus Alexandrium produce the neurotoxin saxitoxin (STX), responsible for paralytic shellfish poisoning (PSP) and accumulates in marine invertebrates. The recent identification of STX biosynthesis genes allowed us to investigate the expression of sxtA4 at different growth stages in Alexandrium catenella Group IV. We found no significant differences in expression of sxtA4, despite significant differences in STX levels at different growth stages (P < 0.023). Three reference genes were tested for normalisation: actin, cytochrome b (cob), and the large subunit ribosomal RNA (LSU rDNA). cob was most stably expressed but the combination of two reference genes, actin and cob, resulted in the best stability factor. Most genomic sequences of sxtA4 from A. catenella were in a clade that included sequences from Alexandrium fundyense Group I, however, one paralogue was not related to the others, suggesting recombination or lateral transfer. A comparison of the sxtA4 cDNA sequences with genomic DNA sequences indicated the possibility of transcript editing and the preferential transcription of certain genomic DNA loci. The results show that, in dinoflagellates, post-transcriptional mechanisms play a major role in the regulation of saxitoxin biosynthesis.
Collapse
Affiliation(s)
- Maria Wiese
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia.
| | - Shauna A Murray
- Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia; Plant Functional Biology and Climate Change Cluster, University of Technology, Sydney, NSW 2007, Australia
| | - Alfonsus Alvin
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Brett A Neilan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia.
| |
Collapse
|
30
|
Wiese M, Murray SA, Alvin A, Neilan BA. WITHDRAWN: Gene expression and molecular evolution of sxtA4 in a saxitoxin producing dinoflagellate Alexandrium catenella. Toxicon 2014:S0041-0101(14)00193-7. [PMID: 25080311 DOI: 10.1016/j.toxicon.2014.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 07/08/2014] [Accepted: 07/15/2014] [Indexed: 10/25/2022]
Abstract
This article has been withdrawn at the request of the authors and editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
Collapse
Affiliation(s)
- Maria Wiese
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia
| | - Shauna A Murray
- Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia; Plant Functional Biology and Climate Change Cluster, University of Technology, Sydney, NSW 2007, Australia
| | - Alfonsus Alvin
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia
| | - Brett A Neilan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia
| |
Collapse
|
31
|
Lee R, Lai H, Malik SB, Saldarriaga JF, Keeling PJ, Slamovits CH. Analysis of EST data of the marine protist Oxyrrhis marina, an emerging model for alveolate biology and evolution. BMC Genomics 2014; 15:122. [PMID: 24512041 PMCID: PMC3942190 DOI: 10.1186/1471-2164-15-122] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 02/06/2014] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The alveolates include a large number of important lineages of protists and algae, among which are three major eukaryotic groups: ciliates, apicomplexans and dinoflagellates. Collectively alveolates are present in virtually every environment and include a vast diversity of cell shapes, molecular and cellular features and feeding modes including lifestyles such as phototrophy, phagotrophy/predation and intracellular parasitism, in addition to a variety of symbiotic associations. Oxyrrhis marina is a well-known model for heterotrophic protist biology, and is now emerging as a useful organism to explore the many changes that occurred during the origin and diversification of dinoflagellates by virtue of its phylogenetic position at the base of the dinoflagellate tree. RESULTS We have generated and analysed expressed sequence tag (EST) sequences from the alveolate Oxyrrhis marina in order to shed light on the evolution of a number of dinoflagellate characteristics, especially regarding the emergence of highly unusual genomic features. We found that O. marina harbours extensive gene redundancy, indicating high rates of gene duplication and transcription from multiple genomic loci. In addition, we observed a correlation between expression level and copy number in several genes, suggesting that copy number may contribute to determining transcript levels for some genes. Finally, we analyze the genes and predicted products of the recently discovered Dinoflagellate Viral Nuclear Protein, and several cases of horizontally acquired genes. CONCLUSION The dataset presented here has proven very valuable for studying this important group of protists. Our analysis indicates that gene redundancy is a pervasive feature of dinoflagellate genomes, thus the mechanisms involved in its generation must have arisen early in the evolution of the group.
Collapse
Affiliation(s)
- Renny Lee
- Department of Biochemistry and Molecular Biology, Dalhousie University, B3H4R2 Halifax, NS, Canada
| | - Hugo Lai
- Department of Biochemistry and Molecular Biology, Dalhousie University, B3H4R2 Halifax, NS, Canada
| | - Shehre Banoo Malik
- Canadian Institute for Advanced Research, Program in Integrated Microbial Biodiversity, Alberta, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, B3H4R2 Halifax, NS, Canada
| | - Juan F Saldarriaga
- Botany Department, University of British Columbia, V6T1Z4 Vancouver, BS, Canada
| | - Patrick J Keeling
- Canadian Institute for Advanced Research, Program in Integrated Microbial Biodiversity, Alberta, Canada
- Botany Department, University of British Columbia, V6T1Z4 Vancouver, BS, Canada
| | - Claudio H Slamovits
- Canadian Institute for Advanced Research, Program in Integrated Microbial Biodiversity, Alberta, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, B3H4R2 Halifax, NS, Canada
| |
Collapse
|
32
|
Global analysis of mRNA half-lives and de novo transcription in a dinoflagellate, Karenia brevis. PLoS One 2013; 8:e66347. [PMID: 23776661 PMCID: PMC3679056 DOI: 10.1371/journal.pone.0066347] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 05/06/2013] [Indexed: 12/24/2022] Open
Abstract
Dinoflagellates possess many physiological processes that appear to be under post-transcriptional control. However, the extent to which their genes are regulated post-transcriptionally remains unresolved. To gain insight into the roles of differential mRNA stability and de novo transcription in dinoflagellates, we biosynthetically labeled RNA with 4-thiouracil to isolate newly transcribed and pre-existing RNA pools in Karenia brevis. These isolated fractions were then used for analysis of global mRNA stability and de novo transcription by hybridization to a K. brevis microarray. Global K. brevis mRNA half-lives were calculated from the ratio of newly transcribed to pre-existing RNA for 7086 array features using the online software HALO (Half-life Organizer). Overall, mRNA half-lives were substantially longer than reported in other organisms studied at the global level, ranging from 42 minutes to greater than 144 h, with a median of 33 hours. Consistent with well-documented trends observed in other organisms, housekeeping processes, including energy metabolism and transport, were significantly enriched in the most highly stable messages. Shorter-lived transcripts included a higher proportion of transcriptional regulation, stress response, and other response/regulatory processes. One such family of proteins involved in post-transcriptional regulation in chloroplasts and mitochondria, the pentatricopeptide repeat (PPR) proteins, had dramatically shorter half-lives when compared to the arrayed transcriptome. As transcript abundances for PPR proteins were previously observed to rapidly increase in response to nutrient addition, we queried the newly synthesized RNA pools at 1 and 4 h following nitrate addition to N-depleted cultures. Transcriptome-wide there was little evidence of increases in the rate of de novo transcription during the first 4 h, relative to that in N-depleted cells, and no evidence for increased PPR protein transcription. These results lend support to the growing consensus of post-transcriptional control of gene expression in dinoflagellates.
Collapse
|
33
|
Wang DZ, Zhang YJ, Zhang SF, Lin L, Hong HS. Quantitative proteomic analysis of cell cycle of the dinoflagellate Prorocentrum donghaiense (Dinophyceae). PLoS One 2013; 8:e63659. [PMID: 23691081 PMCID: PMC3655175 DOI: 10.1371/journal.pone.0063659] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 04/05/2013] [Indexed: 12/29/2022] Open
Abstract
Dinoflagellates are the major causative agents of harmful algal blooms in the coastal zone, which has resulted in adverse effects on the marine ecosystem and public health, and has become a global concern. Knowledge of cell cycle regulation in proliferating cells is essential for understanding bloom dynamics, and so this study compared the protein profiles of Prorocentrum donghaiense at different cell cycle phases and identified differentially expressed proteins using 2-D fluorescence difference gel electrophoresis combined with MALDI-TOF-TOF mass spectrometry. The results showed that the synchronized cells of P. donghaiense completed a cell cycle within 24 hours and cell division was phased with the diurnal cycle. Comparison of the protein profiles at four cell cycle phases (G1, S, early and late G2/M) showed that 53 protein spots altered significantly in abundance. Among them, 41 were identified to be involved in a variety of biological processes, e.g. cell cycle and division, RNA metabolism, protein and amino acid metabolism, energy and carbon metabolism, oxidation-reduction processes, and ABC transport. The periodic expression of these proteins was critical to maintain the proper order and function of the cell cycle. This study, to our knowledge, for the first time revealed the major biological processes occurring at different cell cycle phases which provided new insights into the mechanisms regulating the cell cycle and growth of dinoflagellates.
Collapse
Affiliation(s)
- Da-Zhi Wang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen, China.
| | | | | | | | | |
Collapse
|
34
|
Diversity of Eukaryotic Translational Initiation Factor eIF4E in Protists. Comp Funct Genomics 2012; 2012:134839. [PMID: 22778692 PMCID: PMC3388326 DOI: 10.1155/2012/134839] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 04/09/2012] [Indexed: 01/01/2023] Open
Abstract
The greatest diversity of eukaryotic species is within the microbial eukaryotes, the protists, with plants and fungi/metazoa representing just two of the estimated seventy five lineages of eukaryotes. Protists are a diverse group characterized by unusual genome features and a wide range of genome sizes from 8.2 Mb in the apicomplexan parasite Babesia bovis to 112,000-220,050 Mb in the dinoflagellate Prorocentrum micans. Protists possess numerous cellular, molecular and biochemical traits not observed in “text-book” model organisms. These features challenge some of the concepts and assumptions about the regulation of gene expression in eukaryotes. Like multicellular eukaryotes, many protists encode multiple eIF4Es, but few functional studies have been undertaken except in parasitic species. An earlier phylogenetic analysis of protist eIF4Es indicated that they cannot be grouped within the three classes that describe eIF4E family members from multicellular organisms. Many more protist sequences are now available from which three clades can be recognized that are distinct from the plant/fungi/metazoan classes. Understanding of the protist eIF4Es will be facilitated as more sequences become available particularly for the under-represented opisthokonts and amoebozoa. Similarly, a better understanding of eIF4Es within each clade will develop as more functional studies of protist eIF4Es are completed.
Collapse
|
35
|
The falsifiability of the models for the origin of eukaryotes. Curr Genet 2011; 57:367-90. [DOI: 10.1007/s00294-011-0357-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 09/29/2011] [Accepted: 09/30/2011] [Indexed: 01/13/2023]
|
36
|
Morey JS, Monroe EA, Kinney AL, Beal M, Johnson JG, Hitchcock GL, Van Dolah FM. Transcriptomic response of the red tide dinoflagellate, Karenia brevis, to nitrogen and phosphorus depletion and addition. BMC Genomics 2011; 12:346. [PMID: 21729317 PMCID: PMC3149589 DOI: 10.1186/1471-2164-12-346] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 07/05/2011] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND The role of coastal nutrient sources in the persistence of Karenia brevis red tides in coastal waters of Florida is a contentious issue that warrants investigation into the regulation of nutrient responses in this dinoflagellate. In other phytoplankton studied, nutrient status is reflected by the expression levels of N- and P-responsive gene transcripts. In dinoflagellates, however, many processes are regulated post-transcriptionally. All nuclear encoded gene transcripts studied to date possess a 5' trans-spliced leader (SL) sequence suggestive, based on the trypanosome model, of post-transcriptional regulation. The current study therefore sought to determine if the transcriptome of K. brevis is responsive to nitrogen and phosphorus and is informative of nutrient status. RESULTS Microarray analysis of N-depleted K. brevis cultures revealed an increase in the expression of transcripts involved in N-assimilation (nitrate and ammonium transporters, glutamine synthetases) relative to nutrient replete cells. In contrast, a transcriptional signal of P-starvation was not apparent despite evidence of P-starvation based on their rapid growth response to P-addition. To study transcriptome responses to nutrient addition, the limiting nutrient was added to depleted cells and changes in global gene expression were assessed over the first 48 hours following nutrient addition. Both N- and P-addition resulted in significant changes in approximately 4% of genes on the microarray, using a significance cutoff of 1.7-fold and p ≤ 10-4. By far, the earliest responding genes were dominated in both nutrient treatments by pentatricopeptide repeat (PPR) proteins, which increased in expression up to 3-fold by 1 h following nutrient addition. PPR proteins are nuclear encoded proteins involved in chloroplast and mitochondria RNA processing. Correspondingly, other functions enriched in response to both nutrients were photosystem and ribosomal genes. CONCLUSIONS Microarray analysis provided transcriptomic evidence for N- but not P-limitation in K. brevis. Transcriptomic responses to the addition of either N or P suggest a concerted program leading to the reactivation of chloroplast functions. Even the earliest responding PPR protein transcripts possess a 5' SL sequence that suggests post-transcriptional control. Given the current state of knowledge of dinoflagellate gene regulation, it is currently unclear how these rapid changes in such transcript levels are achieved.
Collapse
Affiliation(s)
- Jeanine S Morey
- Marine Biotoxins Program, NOAA National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Rd., Charleston, SC 29412, USA
| | - Emily A Monroe
- Marine Biotoxins Program, NOAA National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Rd., Charleston, SC 29412, USA
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Dr. La Jolla, CA 92093, USA
| | - Amanda L Kinney
- Marine Biotoxins Program, NOAA National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Rd., Charleston, SC 29412, USA
| | - Marion Beal
- Marine Biotoxins Program, NOAA National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Rd., Charleston, SC 29412, USA
| | - Jillian G Johnson
- Marine Biotoxins Program, NOAA National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Rd., Charleston, SC 29412, USA
| | - Gary L Hitchcock
- Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 4600 Rickenbacker Cswy., Miami, FL 33149, USA
| | - Frances M Van Dolah
- Marine Biotoxins Program, NOAA National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Rd., Charleston, SC 29412, USA
| |
Collapse
|