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Zhang J, Yang Q, Liu Q, Liu S, Zhu Y, Yao J, Wang H, Guan W. The responses of harmful dinoflagellate Karenia mikimotoi to simulated ocean acidification at the transcriptional level. HARMFUL ALGAE 2022; 111:102167. [PMID: 35016771 DOI: 10.1016/j.hal.2021.102167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 12/06/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Abstract
The HAB-forming, toxic dinoflagellate Karenia mikimotoi, previously found to benefit from ocean acidification (OA), was cultivated to investigate its transcriptional response to simulated OA for 30 generations. Batch cultures were grown under two CO2 concentrations, 450 (control) and 1100 (simulated OA) μatm, and physiological parameters [growth, pigments, catalase (CAT), glutathione reductase (GR), and superoxide dismutase (SOD) activity], as well as transcriptomes (obtained via RNA-seq), were compared. Chlorophyll a (Chl a) and carotenoid (Caro) contents, as well as CAT and GR activities, were significantly increased under OA conditions. Transcriptomic analysis revealed 2,490 differentially expressed unigenes in response to OA, which comprised 1.54% of all unigenes. A total of 1,121 unigenes were upregulated, and 1,369 unigenes were downregulated in OA compared to control conditions. The downregulated expression of bicarbonate transporter and carbonic anhydrase genes was a landmark of OA acclimation. Key genes involved in energy metabolism, e.g., photosynthesis, tricarboxylic acid cycle, oxidative phosphorylation, and nitrogen metabolism, were highly upregulated under OA, contributing to increases in the Chl a (55.05%) and Caro (28.37%). The enhanced antioxidant enzyme activities (i.e. CAT, GR) and upregulated genes (i.e. glutathione peroxidase, ascorbate peroxidase, heat shock protein, 20S proteasome, aldehyde dehydrogenase, and apolipoprotein) benefit cells against the potential lower pH stress condition under OA. In addition, the downregulation of four genes associated with motility suggested that the preserved energy could further boost growth. In conclusion, the present study suggests that K. mikimotoi exhibits efficient gene expression regulation for the utilization of energy and resistance to OA-induced stress. Taken together, K. mikimotoi appeared as a tolerant species in response to OA. Thus, more extensive algal blooms that threaten marine organisms are likely in the future. These findings expand current knowledge on the gene expression of HAB-forming species in response to future OA.
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Affiliation(s)
- Jiazhu Zhang
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Qiongying Yang
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Qianlou Liu
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Shuqi Liu
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Yue Zhu
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Jiang Yao
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Hong Wang
- Department of Medical Laboratory Technology, Xinyang Vocational and Technical College, Xinyang, Henan 464000, China
| | - Wanchun Guan
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
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Coyne KJ, Salvitti LR, Mangum AM, Ozbay G, Main CR, Kouhanestani ZM, Warner ME. Interactive effects of light, CO2 and temperature on growth and resource partitioning by the mixotrophic dinoflagellate, Karlodinium veneficum. PLoS One 2021; 16:e0259161. [PMID: 34705875 PMCID: PMC8550395 DOI: 10.1371/journal.pone.0259161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 10/14/2021] [Indexed: 11/25/2022] Open
Abstract
There is little information on the impacts of climate change on resource partitioning for mixotrophic phytoplankton. Here, we investigated the hypothesis that light interacts with temperature and CO2 to affect changes in growth and cellular carbon and nitrogen content of the mixotrophic dinoflagellate, Karlodinium veneficum, with increasing cellular carbon and nitrogen content under low light conditions and increased growth under high light conditions. Using a multifactorial design, the interactive effects of light, temperature and CO2 were investigated on K. veneficum at ambient temperature and CO2 levels (25°C, 375 ppm), high temperature (30°C, 375 ppm CO2), high CO2 (30°C, 750 ppm CO2), or a combination of both high temperature and CO2 (30°C, 750 ppm CO2) at low light intensities (LL: 70 μmol photons m-2 s-2) and light-saturated conditions (HL: 140 μmol photons m-2 s-2). Results revealed significant interactions between light and temperature for all parameters. Growth rates were not significantly different among LL treatments, but increased significantly with temperature or a combination of elevated temperature and CO2 under HL compared to ambient conditions. Particulate carbon and nitrogen content increased in response to temperature or a combination of elevated temperature and CO2 under LL conditions, but significantly decreased in HL cultures exposed to elevated temperature and/or CO2 compared to ambient conditions at HL. Significant increases in C:N ratios were observed only in the combined treatment under LL, suggesting a synergistic effect of temperature and CO2 on carbon assimilation, while increases in C:N under HL were driven only by an increase in CO2. Results indicate light-driven variations in growth and nutrient acquisition strategies for K. veneficum that may benefit this species under anticipated climate change conditions (elevated light, temperature and pCO2) while also affecting trophic transfer efficiency during blooms of this species.
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Affiliation(s)
- Kathryn J. Coyne
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, Delaware, United States of America
- * E-mail:
| | - Lauren R. Salvitti
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, Delaware, United States of America
| | - Alicia M. Mangum
- Department of Agriculture and Natural Resources, Delaware State University, Dover, Delaware, United States of America
| | - Gulnihal Ozbay
- Department of Agriculture and Natural Resources, Delaware State University, Dover, Delaware, United States of America
| | - Christopher R. Main
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, Delaware, United States of America
- Department of Natural Resources and Environmental Control, Dover, Delaware, United States of America
| | - Zohreh M. Kouhanestani
- Department of Agriculture and Natural Resources, Delaware State University, Dover, Delaware, United States of America
- Department of Fisheries and Environmental Sciences, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Golestan, Iran
| | - Mark E. Warner
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, Delaware, United States of America
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Liu Q, Wang Y, Li Y, Li Y, Wang Y, Zhou B, Zhou Z. Nutrient Alteration Drives the Impacts of Seawater Acidification on the Bloom-Forming Dinoflagellate Karenia mikimotoi. FRONTIERS IN PLANT SCIENCE 2021; 12:739159. [PMID: 34751224 PMCID: PMC8572056 DOI: 10.3389/fpls.2021.739159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
Seawater acidification and nutrient alteration are two dominant environmental factors in coastal environments that influence the dynamics and succession of marine microalgae. However, the impacts of their combination have seldom been recorded. A simulated experimental system was set up to mimic the effects of elevated acidification on a bloom-forming dinoflagellate, Karenia mikimotoi, exposed to different nutrient conditions, and the possible mechanism was discussed. The results showed that acidification at different pH levels of 7.6 or 7.4 significantly influenced microalgal growth (p<0.05) compared with the control at pH 8.0. Mitochondria, the key sites of aerobic respiration and energy production, were impaired in a pH-dependent manner, and a simultaneous alteration of reactive oxygen species (ROS) production occurred. Cytochrome c oxidase (COX) and citrate synthase (CS), two mitochondrial metabolism-related enzymes, were actively induced with acidification exposure, suggesting the involvement of the mitochondrial pathway in coping with acidification. Moreover, different nutrient statuses indicated by various N:P ratios of 7:1 (N limitation) and 52:1 (P limitation) dramatically altered the impacts of acidification compared with those exposed to an N:P ratio of 17:1 (control), microalgal growth at pH 7.4 was obviously accelerated with the elevation of the nutrient ratio compared to that at pH 8.1 (p<0.05), and nutrient limitations seemed beneficial for growth in acidifying conditions. The production of alkaline phosphatase (AP) and acid phosphatase (AcP), an effective index indicating the microalgal growth status, significantly increased at the same time (p<0.05), which further supported this speculation. However, nitrate reductase (NR) was slightly inhibited. Hemolytic toxin production showed an obvious increase as the N:P ratio increased when exposed to acidification. Taken together, mitochondrial metabolism was suspected to be involved in the process of coping with acidification, and nutrient alterations, especially P limitation, could effectively alleviate the negative impacts induced by acidification. The obtained results might be a possible explanation for the competitive fitness of K. mikimotoi during bloom development.
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Affiliation(s)
- Qian Liu
- College of Marine Life Science, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yanqun Wang
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China
| | - Yuanyuan Li
- College of Marine Life Science, Ocean University of China, Qingdao, China
| | - Yijun Li
- College of Life Sciences, Qingdao University, Qingdao, China
| | - You Wang
- College of Marine Life Science, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Bin Zhou
- College of Marine Life Science, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhongyuan Zhou
- College of Marine Life Science, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
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The Bloom-Forming Dinoflagellate Karenia mikimotoi Adopts Different Growth Modes When Exposed to Short or Long Period of Seawater Acidification. Toxins (Basel) 2021; 13:toxins13090629. [PMID: 34564633 PMCID: PMC8470136 DOI: 10.3390/toxins13090629] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/10/2021] [Accepted: 08/22/2021] [Indexed: 11/29/2022] Open
Abstract
Impacts of ocean acidification (OA) on noncalcifying organisms and the possibly responsible mechanism have aroused great research interests with the intensification of global warming. The present study focused on a noxious, noncalcifying, bloom-forming dinoflagellate, Karenia mikimotoi (K. mikimotoi), and its variation of growth patterns exposed to different periods of seawater acidification with stressing gradients was discussed. The dinoflagellates under short-time acidifying stress (2d) with different levels of CO2 presented significant growth inhibition (p < 0.05). The cell cycle was obviously inhibited at S phase, and the photosynthetic carbon fixation was also greatly suppressed (p < 0.05). Apoptosis was observed and the apoptotic rate increased with the increment of pCO2. Similar tendencies were observed in the key components of mitochondrial apoptotic pathway (the mitochondrial membrane potential (MMP), Caspase-3 and -9, and Bax/Bcl-2 ratio). However, under prolonged stressing time (8 d and 15 d), the growth of dinoflagellates was recovered or even stimulated, the photosynthetic carbon fixation was significantly increased (p < 0.05), the cell cycle of division presented little difference with those in the control, and no apoptosis was observed (p > 0.05). Besides, acidification adjusted by HCl addition and CO2 enrichment resulted in different growth performances, while the latter had a more negative impact. The results of present study indicated that (1) the short-time exposure to acidified seawater led to reduced growth performance via inducing apoptosis, blocking of cell cycle, and the alteration in photosynthetic carbon fixation. (2) K. mikimotoi had undergone adaptive changes under long-term exposure to CO2 induced seawater acidification. This further demonstrated that K. mikimotoi has strong adaptability in the face of seawater acidification, and this may be one of the reasons for the frequent outbreak of red tide. (3) Ions that dissociated by the dissolved CO2, instead of H+ itself, were more important for the impacts induced by the acidification. This work thus provides a new perspective and a possible explanation for the dominance of K. mikimotoi during the occurrence of HABs.
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Raven JA, Suggett DJ, Giordano M. Inorganic carbon concentrating mechanisms in free-living and symbiotic dinoflagellates and chromerids. JOURNAL OF PHYCOLOGY 2020; 56:1377-1397. [PMID: 32654150 DOI: 10.1111/jpy.13050] [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: 11/26/2019] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
Photosynthetic dinoflagellates are ecologically and biogeochemically important in marine and freshwater environments. However, surprisingly little is known of how this group acquires inorganic carbon or how these diverse processes evolved. Consequently, how CO2 availability ultimately influences the success of dinoflagellates over space and time remains poorly resolved compared to other microalgal groups. Here we review the evidence. Photosynthetic core dinoflagellates have a Form II RuBisCO (replaced by Form IB or Form ID in derived dinoflagellates). The in vitro kinetics of the Form II RuBisCO from dinoflagellates are largely unknown, but dinoflagellates with Form II (and other) RuBisCOs have inorganic carbon concentrating mechanisms (CCMs), as indicated by in vivo internal inorganic C accumulation and affinity for external inorganic C. However, the location of the membrane(s) at which the essential active transport component(s) of the CCM occur(s) is (are) unresolved; isolation and characterization of functionally competent chloroplasts would help in this respect. Endosymbiotic Symbiodiniaceae (in Foraminifera, Acantharia, Radiolaria, Ciliata, Porifera, Acoela, Cnidaria, and Mollusca) obtain inorganic C by transport from seawater through host tissue. In corals this transport apparently provides an inorganic C concentration around the photobiont that obviates the need for photobiont CCM. This is not the case for tridacnid bivalves, medusae, or, possibly, Foraminifera. Overcoming these long-standing knowledge gaps relies on technical advances (e.g., the in vitro kinetics of Form II RuBisCO) that can functionally track the fate of inorganic C forms.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
- Faculty of Science, University of Technology, Sydney, Climate Change Cluster, Ultimo, Sydney, New South Wales, 2007, Australia
- School of Biological Science, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - David J Suggett
- Faculty of Science, University of Technology, Sydney, Climate Change Cluster, Ultimo, Sydney, New South Wales, 2007, Australia
| | - Mario Giordano
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131, Ancona, Italy
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Algatech, Trebon, Czech Republic
- National Research Council, Institute of Marine Science ISMAR, Venezia, Italy
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Seto DS, Karp-Boss L, Wells ML. Effects of increasing temperature and acidification on the growth and competitive success of Alexandrium catenella from the Gulf of Maine. HARMFUL ALGAE 2019; 89:101670. [PMID: 31672235 DOI: 10.1016/j.hal.2019.101670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/30/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Climate driven increases in ocean temperature and pCO2 have the potential to alter the growth and prevalence of future Harmful Algal Blooms (HABs), but systematic studies on how climate drivers influence toxic algal species relative to non-toxic phytoplankton are lacking. In particular, little is known about how future climate scenarios will affect the growth of the toxic dinoflagellate Alexandrium catenella, which is responsible for the paralytic shellfish poisoning (PSP) events that threaten the health and economy of coastal communities in the Gulf of Maine and elsewhere. The growth responses of A. catenella and two other naturally co-occurring dinoflagellates in the Gulf of Maine-Scrippsiella sp., and Amphidinium carterae-were studied in mono and mixed species cultures. Experimental treatments tested the effects of elevated temperature (20 °C), lower pH (7.8), and the combination of elevated temperature and lower pH on growth rates relative to those in near-current conditions (15 °C; pH 8.1). Growth rates of A. catenella decreased under elevated temperature and lower pH conditions, a response that was largely attributable to the effect of temperature. In contrast, growth rates of Scrippsiella sp. and A. carterae increased under elevated temperature and lower pH conditions, with temperature also being the primary driver of the response. These trends did not change substantially when these species were grown in mixed cultures (A. catenella + Scrippsiella sp., and A. catenella + A. carterae), indicating that allelopathic or competitive interactions did not affect the experimental outcome under the conditions tested. These findings suggest that A. catenella blooms may become less prevalent in the southern regions of the Gulf of Maine, but potentially more prevalent in the northeastern regions of the Gulf of Maine with continued climate change.
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Affiliation(s)
- Drajad S Seto
- School of Marine Science, University of Maine, Orono, ME, 04469, USA.
| | - Lee Karp-Boss
- School of Marine Science, University of Maine, Orono, ME, 04469, USA.
| | - Mark L Wells
- School of Marine Science, University of Maine, Orono, ME, 04469, USA; State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, 36 Baochubei Road, Hangzhou, 310012, China.
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