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Advances in Research of Algae, Cyanobacteria, and Phytoplankton

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Plant Sciences".

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 20708

Special Issue Editor

Dr. Elena R. Tarakhovskaya

E-Mail Website
Guest Editor
1. Department of Plant Physiology and Biochemistry, Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
2. Laboratory of Mutagenesis and Genetic Toxicology, Vavilov Institute of General Genetics, Saint-Petersburg Branch, Russian Academy of Sciences, 199034 Saint-Petersburg, Russia
Interests: biochemistry and physiology of marine macrophytes; algal secondary metabolites; GC-MS based metabolomics; reactive oxygen species; phytohormones; mixotrophy; drought resistance; hemotaxonomy

Special Issue Information

Dear Colleagues,

We are pleased to announce a new Special Issue of the International Journal of Molecular Sciences entitled “Advances in Research on Algae, Cyanobacteria, and Phytoplankton”. This issue was conceived as a collection of high-quality research papers and reviews covering recent advances in algal biology.

As key components of water ecosystems and sources of numerous valuable compounds, algae are attracting increasing attention in both science and technology. During the last few decades, considerable progress has been achieved in this field due to the involvement of molecular techniques in the study of different cyanobacteria and algae, from model unicellular species, such as Synechocystis and Chlamydomonas, to giant seaweeds.

The Special Issue welcomes research on such aspects of algal science as biochemistry and physiology, molecular biology and genetics, chemotaxonomy, molecular taxonomy and phylogenetics, cell biology, and biotechnology. In addition to studies of seaweeds and microalgae, we also welcome research on cyanobacteria and lichens as well as interdisciplinary studies.

Dr. Elena R. Tarakhovskaya
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • algae
  • seaweeds
  • cyanobacteria
  • phytoplankton
  • biochemistry
  • molecular biology
  • biotechnology

Published Papers (16 papers)

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Research

17 pages, 5015 KiB  
Article
Impact of Carbon Fixation, Distribution and Storage on the Production of Farnesene and Limonene in Synechocystis PCC 6803 and Synechococcus PCC 7002
by Marine Vincent, Victoire Blanc-Garin, Célia Chenebault, Mattia Cirimele, Sandrine Farci, Luis Fernando Garcia-Alles, Corinne Cassier-Chauvat and Franck Chauvat
Int. J. Mol. Sci. 2024, 25(7), 3827; https://doi.org/10.3390/ijms25073827 - 29 Mar 2024
Viewed by 817
Abstract
Terpenes are high-value chemicals which can be produced by engineered cyanobacteria from sustainable resources, solar energy, water and CO2. We previously reported that the euryhaline unicellular cyanobacteria Synechocystis sp. PCC 6803 (S.6803) and Synechococcus sp. PCC 7002 (S.7002) produce farnesene and [...] Read more.
Terpenes are high-value chemicals which can be produced by engineered cyanobacteria from sustainable resources, solar energy, water and CO2. We previously reported that the euryhaline unicellular cyanobacteria Synechocystis sp. PCC 6803 (S.6803) and Synechococcus sp. PCC 7002 (S.7002) produce farnesene and limonene, respectively, more efficiently than other terpenes. In the present study, we attempted to enhance farnesene production in S.6803 and limonene production in S.7002. Practically, we tested the influence of key cyanobacterial enzymes acting in carbon fixation (RubisCO, PRK, CcmK3 and CcmK4), utilization (CrtE, CrtR and CruF) and storage (PhaA and PhaB) on terpene production in S.6803, and we compared some of the findings with the data obtained in S.7002. We report that the overproduction of RubisCO from S.7002 and PRK from Cyanothece sp. PCC 7425 increased farnesene production in S.6803, but not limonene production in S.7002. The overexpression of the crtE genes (synthesis of terpene precursors) from S.6803 or S.7002 did not increase farnesene production in S.6803. In contrast, the overexpression of the crtE gene from S.6803, but not S.7002, increased farnesene production in S.7002, emphasizing the physiological difference between these two model cyanobacteria. Furthermore, the deletion of the crtR and cruF genes (carotenoid synthesis) and phaAB genes (carbon storage) did not increase the production of farnesene in S.6803. Finally, as a containment strategy of genetically modified strains of S.6803, we report that the deletion of the ccmK3K4 genes (carboxysome for CO2 fixation) did not affect the production of limonene, but decreased the production of farnesene in S.6803. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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0 pages, 2959 KiB  
Article
Molecular Insights into the Synergistic Effects of Putrescine and Ammonium on Dinoflagellates
by Yanfei Wang and Kathryn J. Coyne
Int. J. Mol. Sci. 2024, 25(2), 1306; https://doi.org/10.3390/ijms25021306 - 21 Jan 2024
Viewed by 919
Abstract
Ammonium and polyamines are essential nitrogen metabolites in all living organisms. Crosstalk between ammonium and polyamines through their metabolic pathways has been demonstrated in plants and animals, while no research has been directed to explore this relationship in algae or to investigate the [...] Read more.
Ammonium and polyamines are essential nitrogen metabolites in all living organisms. Crosstalk between ammonium and polyamines through their metabolic pathways has been demonstrated in plants and animals, while no research has been directed to explore this relationship in algae or to investigate the underlying molecular mechanisms. Previous research demonstrated that high concentrations of ammonium and putrescine were among the active substances in bacteria-derived algicide targeting dinoflagellates, suggesting that the biochemical inter-connection and/or interaction of these nitrogen compounds play an essential role in controlling these ecologically important algal species. In this research, putrescine, ammonium, or a combination of putrescine and ammonium was added to cultures of three dinoflagellate species to explore their effects. The results demonstrated the dose-dependent and species-specific synergistic effects of putrescine and ammonium on these species. To further explore the molecular mechanisms behind the synergistic effects, transcriptome analysis was conducted on dinoflagellate Karlodinium veneficum treated with putrescine or ammonium vs. a combination of putrescine and ammonium. The results suggested that the synergistic effects of putrescine and ammonium disrupted polyamine homeostasis and reduced ammonium tolerance, which may have contributed to the cell death of K. veneficum. There was also transcriptomic evidence of damage to chloroplasts and impaired photosynthesis of K. veneficum. This research illustrates the molecular mechanisms underlying the synergistic effects of the major nitrogen metabolites, ammonium and putrescine, in dinoflagellates and provides direction for future studies on polyamine biology in algal species. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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15 pages, 3309 KiB  
Article
Contribution to a Sustainable Society: Biosorption of Precious Metals Using the Microalga Galdieria
by Eri Adams, Kazuki Maeda, Yuki Kamemoto, Kazuho Hirai and Egi Tritya Apdila
Int. J. Mol. Sci. 2024, 25(2), 704; https://doi.org/10.3390/ijms25020704 - 5 Jan 2024
Viewed by 772
Abstract
The red microalga Galdieria sp. is an extremophile that inhabits acidic hot sulphur springs and grows heterotrophically to a high cell density. These characteristics make Galdieria suitable for commercial applications as stable mass production is the key to success in the algae business. [...] Read more.
The red microalga Galdieria sp. is an extremophile that inhabits acidic hot sulphur springs and grows heterotrophically to a high cell density. These characteristics make Galdieria suitable for commercial applications as stable mass production is the key to success in the algae business. Galdieria has great potential as a precious metal adsorbent to provide a sustainable, efficient and environmentally benign method for urban mining and artisanal small-scale gold mining. The efficiency and selectivity in capturing precious metals, gold and palladium from metal solutions by a Galdieria-derived adsorbent was assessed relative to commercially used adsorbents, ion exchange resin and activated charcoal. As it is only the surface of Galdieria cells that affect metal adsorption, the cell content was analysed to determine the manner of utilisation of those metabolites. Galdieria was shown to be protein-rich and contain beneficial metabolites, the levels of which could shift depending on the growth conditions. Separating the cell content from the adsorbent could improve the adsorption efficiency and reduce CO2 emissions during the metal collection process. The commercial applications of Galdieria appear promising: growth is quick and dense; the precious metal adsorption capacity is highly efficient and selective in acidic conditions, especially at low metal concentrations; and the cell content is nutrient-rich. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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16 pages, 2874 KiB  
Article
A Blue Light-Responsive Strong Synthetic Promoter Based on Rational Design in Chlamydomonas reinhardtii
by Chen Chen, Jun Chen, Guangxi Wu, Liling Li, Zhangli Hu and Xiaozheng Li
Int. J. Mol. Sci. 2023, 24(19), 14596; https://doi.org/10.3390/ijms241914596 - 27 Sep 2023
Cited by 1 | Viewed by 1112
Abstract
Chlamydomonas reinhardtii (C. reinhardtii) is a single-cell green alga that can be easily genetically manipulated. With its favorable characteristics of rapid growth, low cost, non-toxicity, and the ability for post-translational protein modification, C. reinhardtii has emerged as an attractive option for [...] Read more.
Chlamydomonas reinhardtii (C. reinhardtii) is a single-cell green alga that can be easily genetically manipulated. With its favorable characteristics of rapid growth, low cost, non-toxicity, and the ability for post-translational protein modification, C. reinhardtii has emerged as an attractive option for the biosynthesis of various valuable products. To enhance the expression level of exogenous genes and overcome the silencing of foreign genes by C. reinhardtii, synthetic promoters such as the chimeric promoter AR have been constructed and evaluated. In this study, a synthetic promoter GA was constructed by hybridizing core fragments from the natural promoters of the acyl carrier protein gene (ACP2) and the glutamate dehydrogenase gene (GDH2). The GA promoter exhibited a significant increase (7 times) in expressing GUS, over the AR promoter as positive control. The GA promoter also displayed a strong responsiveness to blue light (BL), where the GUS expression was doubled compared to the white light (WL) condition. The ability of the GA promoter was further tested in the expression of another exogenous cadA gene, responsible for catalyzing the decarboxylation of lysine to produce cadaverine. The cadaverine yield driven by the GA promoter was increased by 1–2 times under WL and 2–3 times under BL as compared to the AR promoter. This study obtained, for the first time, a blue light-responsive GDH2 minimal fragment in C. reinhardtii, which delivered a doubling effect under BL when used alone or in hybrid. Together with the strong GA synthetic promoter, this study offered useful tools of synthetic biology to the algal biotechnology field. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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17 pages, 3236 KiB  
Article
Metabolic Responses of the Microalga Neochloris oleoabundans to Extracellular Self- and Nonself-DNA
by Mónica A. Zárate-López, Elizabeth Quintana-Rodríguez, Domancar Orona-Tamayo, Víctor Aguilar-Hernández, Jesús A. Araujo-León, Ligia Brito-Argáez, Jorge Molina-Torres, José Luis Hernández-Flores, Víctor M. Loyola-Vargas, Nancy E. Lozoya-Pérez and Edmundo Lozoya-Gloria
Int. J. Mol. Sci. 2023, 24(18), 14172; https://doi.org/10.3390/ijms241814172 - 16 Sep 2023
Cited by 1 | Viewed by 1835
Abstract
Stressed organisms identify intracellular molecules released from damaged cells due to trauma or pathogen infection as components of the innate immune response. These molecules called DAMPs (Damage-Associated Molecular Patterns) are extracellular ATP, sugars, and extracellular DNA, among others. Animals and plants can recognize [...] Read more.
Stressed organisms identify intracellular molecules released from damaged cells due to trauma or pathogen infection as components of the innate immune response. These molecules called DAMPs (Damage-Associated Molecular Patterns) are extracellular ATP, sugars, and extracellular DNA, among others. Animals and plants can recognize their own DNA applied externally (self-exDNA) as a DAMP with a high degree of specificity. However, little is known about the microalgae responses to damage when exposed to DAMPs and specifically to self-exDNAs. Here we compared the response of the oilseed microalgae Neochloris oleoabundans to self-exDNA, with the stress responses elicited by nonself-exDNA, methyl jasmonate (MeJA) and sodium bicarbonate (NaHCO3). We analyzed the peroxidase enzyme activity related to the production of reactive oxygen species (ROS), as well as the production of polyphenols, lipids, triacylglycerols, and phytohormones. After 5 min of addition, self-exDNA induced peroxidase enzyme activity higher than the other elicitors. Polyphenols and lipids were increased by self-exDNA at 48 and 24 h, respectively. Triacylglycerols were increased with all elicitors from addition and up to 48 h, except with nonself-exDNA. Regarding phytohormones, self-exDNA and MeJA increased gibberellic acid, isopentenyladenine, and benzylaminopurine at 24 h. Results show that Neochloris oleoabundans have self-exDNA specific responses. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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14 pages, 3150 KiB  
Article
Ion fluxes Involved in the Adaptation of the Estuarine Diatom Coscinodiscus centralis Ehrenberg to Salinity Stress
by Changping Chen, Xiao Hu, Yahui Gao, Junrong Liang and Lin Sun
Int. J. Mol. Sci. 2023, 24(18), 13683; https://doi.org/10.3390/ijms241813683 - 5 Sep 2023
Viewed by 795
Abstract
Although estuarine diatoms have a wide range of salt tolerance, they are often severely stressed by elevated salt concentrations. It remains poorly understood how estuarine diatoms maintain ionic homeostasis under high-salinity conditions. Using a scanning ion-selective electrode technique, this study determined the fluxes [...] Read more.
Although estuarine diatoms have a wide range of salt tolerance, they are often severely stressed by elevated salt concentrations. It remains poorly understood how estuarine diatoms maintain ionic homeostasis under high-salinity conditions. Using a scanning ion-selective electrode technique, this study determined the fluxes of H+, Na+, and K+ involved in the acclimatization of the estuarine diatom Coscinodiscus centralis Ehrenberg after an elevation in salinity from 15 psu to 35 psu. The C. centralis cells exhibited marked H+ effluxes after a transient treatment (TT, 30 min) and short-term treatment (ST, 24 h). However, a drastic shift of H+ efflux toward an influx was induced in the long-term treatment (LT, 10 days). The Na+ flux under TT, ST, and LT salinity conditions was found to accelerate the Na+ efflux. More pronounced effects were observed under the ST and LT salinity conditions compared to the TT salinity condition. The K+ influx showed a significant increase under the LT salinity condition. However, the salinity-induced Na+/H+ exchange in the estuarine diatom was inhibited by amiloride and sodium orthovanadate. These results indicate that the Na+ extrusion in salt-stressed cells is mainly the result of an active Na+/H+ antiport across the plasma membrane. The pattern of ion fluxes under the TT and ST salinity conditions were different from those under the LT salinity conditions, suggesting an incomplete regulation of the acclimation process in the estuarine diatom under short-term salinity stress. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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23 pages, 4597 KiB  
Article
Phenotypic Analysis and Molecular Characterization of Enlarged Cell Size Mutant in Nannochloropsis oceanica
by Weinan Xu, Yihua Lin, Yu Wang, Yanyan Li, Hongmei Zhu and Hantao Zhou
Int. J. Mol. Sci. 2023, 24(17), 13595; https://doi.org/10.3390/ijms241713595 - 2 Sep 2023
Viewed by 1113
Abstract
The cell cycle is the fundamental cellular process of eukaryotes. Although cell-cycle-related genes have been identified in microalgae, their cell cycle progression differs from species to species. Cell enlargement in microalgae is an essential biological trait. At the same time, there are various [...] Read more.
The cell cycle is the fundamental cellular process of eukaryotes. Although cell-cycle-related genes have been identified in microalgae, their cell cycle progression differs from species to species. Cell enlargement in microalgae is an essential biological trait. At the same time, there are various causes of cell enlargement, such as environmental factors, especially gene mutations. In this study, we first determined the phenotypic and biochemical characteristics of a previously obtained enlarged-cell-size mutant of Nannochloropsis oceanica, which was designated ECS. Whole-genome sequencing analysis of the insertion sites of ECS indicated that the insertion fragment is integrated inside the 5′-UTR of U/P-type cyclin CYCU;1 and significantly decreases the gene expression of this cyclin. In addition, the transcriptome showed that CYCU;1 is a highly expressed cyclin. Furthermore, cell cycle analysis and RT-qPCR of cell-cycle-related genes showed that ECS maintains a high proportion of 4C cells and a low proportion of 1C cells, and the expression level of CYCU;1 in wild-type (WT) cells is significantly increased at the end of the light phase and the beginning of the dark phase. This means that CYCU;1 is involved in cell division in the dark phase. Our results explain the reason for the larger ECS size. Mutation of CYCU;1 leads to the failure of ECS to fully complete cell division in the dark phase, resulting in an enlargement of the cell size and a decrease in cell density, which is helpful to understand the function of CYCU;1 in the Nannochloropsis cell cycle. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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14 pages, 2876 KiB  
Article
Analysis of Predicted Amino Acid Sequences of Diatom Microtubule Center Components
by Darya P. Petrova, Alexey A. Morozov, Nadezhda A. Potapova and Yekaterina D. Bedoshvili
Int. J. Mol. Sci. 2023, 24(16), 12781; https://doi.org/10.3390/ijms241612781 - 14 Aug 2023
Viewed by 783
Abstract
Diatoms synthesize species-specific exoskeletons inside cells under the control of the cytoskeleton and microtubule center. Previous studies have been conducted with the visualization of the microtubule center; however, its composition has not been studied and reliably established. In the present study, several components [...] Read more.
Diatoms synthesize species-specific exoskeletons inside cells under the control of the cytoskeleton and microtubule center. Previous studies have been conducted with the visualization of the microtubule center; however, its composition has not been studied and reliably established. In the present study, several components of MTOC in diatoms, GCP (gamma complex proteins), Aurora A, and centrins have been identified. Analysis of the predicted amino acid sequences of these proteins revealed structural features typical for diatoms. We analyzed the conserved amino acids and the motives necessary for the functioning of proteins. Phylogenetic analysis of GCP showed that all major groups of diatoms are distributed over phylogenetic trees according to their systematic position. This work is a theoretical study; however, it allows drawing some conclusions about the functioning of the studied components and possible ways to regulate them. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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16 pages, 2911 KiB  
Article
Promoting Photosynthetic Production of Dammarenediol-II in Chlamydomonas reinhardtii via Gene Loading and Culture Optimization
by Mei-Li Zhao, Xiang-Yu Li, Cheng-Xiang Lan, Zi-Ling Yuan, Jia-Lin Zhao, Ying Huang, Zhang-Li Hu and Bin Jia
Int. J. Mol. Sci. 2023, 24(13), 11002; https://doi.org/10.3390/ijms241311002 - 2 Jul 2023
Viewed by 1348
Abstract
Ginsenosides are major bioactive compounds found in Panax ginseng that exhibit various pharmaceutical properties. Dammarenediol-II, the nucleus of dammarane-type ginsenosides, is a promising candidate for pharmacologically active triterpenes. Dammarenediol-II synthase (DDS) cyclizes 2,3-oxidosqualene to produce dammarenediol-II. Based on the native terpenoids synthetic pathway, [...] Read more.
Ginsenosides are major bioactive compounds found in Panax ginseng that exhibit various pharmaceutical properties. Dammarenediol-II, the nucleus of dammarane-type ginsenosides, is a promising candidate for pharmacologically active triterpenes. Dammarenediol-II synthase (DDS) cyclizes 2,3-oxidosqualene to produce dammarenediol-II. Based on the native terpenoids synthetic pathway, a dammarane-type ginsenosides synthetic pathway was established in Chlamydomonas reinhardtii by introducing P. ginseng PgDDS, CYP450 enzyme (PgCYP716A47), or/and Arabidopsis thaliana NADPH-cytochrome P450 reductase gene (AtCPR), which is responsible for producing dammarane-type ginsenosides. To enhance productivity, strategies such as “gene loading” and “culture optimizing” were employed. Multiple copies of transgene expression cassettes were introduced into the genome to increase the expression of the key rate-limiting enzyme gene, PgDDS, significantly improving the titer of dammarenediol-II to approximately 0.2 mg/L. Following the culture optimization in an opt2 medium supplemented with 1.5 mM methyl jasmonate under a light:dark regimen, the titer of dammarenediol-II increased more than 13-fold to approximately 2.6 mg/L. The C. reinhardtii strains engineered in this study constitute a good platform for the further production of ginsenosides in microalgae. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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21 pages, 3618 KiB  
Article
Metabolic Adjustment of High Intertidal Alga Pelvetia canaliculata to the Tidal Cycle Includes Oscillations of Soluble Carbohydrates, Phlorotannins, and Citric Acid Content
by Renata Islamova, Nikolay Yanshin, Elizaveta Zamyatkina, Ekaterina Gulk, Ekaterina Zuy, Susan Billig, Claudia Birkemeyer and Elena Tarakhovskaya
Int. J. Mol. Sci. 2023, 24(13), 10626; https://doi.org/10.3390/ijms241310626 - 25 Jun 2023
Cited by 1 | Viewed by 1457
Abstract
The brown alga Pelvetia canaliculata is one of the species successfully adapted to intertidal conditions. Inhabiting the high intertidal zone, Pelvetia spends most of its life exposed to air, where it is subjected to desiccation, light, and temperature stresses. However, the physiological and [...] Read more.
The brown alga Pelvetia canaliculata is one of the species successfully adapted to intertidal conditions. Inhabiting the high intertidal zone, Pelvetia spends most of its life exposed to air, where it is subjected to desiccation, light, and temperature stresses. However, the physiological and biochemical mechanisms allowing this alga to tolerate such extreme conditions are still largely unknown. The objective of our study is to compare the biochemical composition of Pelvetia during the different phases of the tidal cycle. To our knowledge, this study is the first attempt to draft a detailed biochemical network underneath the complex physiological processes, conferring the successful survival of this organism in the harsh conditions of the high intertidal zone of the polar seas. We considered the tide-induced changes in relative water content, stress markers, titratable acidity, pigment, and phlorotannin content, as well as the low molecular weight metabolite profiles (GC-MS-based approach) in Pelvetia thalli. Thallus desiccation was not accompanied by considerable increase in reactive oxygen species content. Metabolic adjustment of P. canaliculata to emersion included accumulation of soluble carbohydrates, various phenolic compounds, including intracellular phlorotannins, and fatty acids. Changes in titratable acidity accompanied by the oscillations of citric acid content imply that some processes related to the crassulacean acid metabolism (CAM) may be involved in Pelvetia adaptation to the tidal cycle. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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14 pages, 3356 KiB  
Article
Plastid Genome Evolution of Two Colony-Forming Benthic Ochrosphaera neapolitana Strains (Coccolithales, Haptophyta)
by Ji-San Ha, Duckhyun Lhee, Robert A. Andersen, Barbara Melkonian, Michael Melkonian and Hwan Su Yoon
Int. J. Mol. Sci. 2023, 24(13), 10485; https://doi.org/10.3390/ijms241310485 - 22 Jun 2023
Viewed by 1115
Abstract
Coccolithophores are well-known haptophytes that produce small calcium carbonate coccoliths, which in turn contribute to carbon sequestration in the marine environment. Despite their important ecological role, only two of eleven haptophyte plastid genomes are from coccolithophores, and those two belong to the order [...] Read more.
Coccolithophores are well-known haptophytes that produce small calcium carbonate coccoliths, which in turn contribute to carbon sequestration in the marine environment. Despite their important ecological role, only two of eleven haptophyte plastid genomes are from coccolithophores, and those two belong to the order Isochrysidales. Here, we report the plastid genomes of two strains of Ochrosphaera neapolitana (Coccolithales) from Spain (CCAC 3688 B) and the USA (A15,280). The newly constructed plastid genomes are the largest in size (116,906 bp and 113,686 bp, respectively) among all the available haptophyte plastid genomes, primarily due to the increased intergenic regions. These two plastid genomes possess a conventional quadripartite structure with a long single copy and short single copy separated by two inverted ribosomal repeats. These two plastid genomes share 110 core genes, six rRNAs, and 29 tRNAs, but CCAC 3688 B has an additional CDS (ycf55) and one tRNA (trnL-UAG). Two large insertions at the intergenic regions (2 kb insertion between ycf35 and ycf45; 0.5 kb insertion in the middle of trnM and trnY) were detected in the strain CCAC 3688 B. We found the genes of light-independent protochlorophyllide oxidoreductase (chlB, chlN, and chlL), which convert protochlorophyllide to chlorophyllide during chlorophyll biosynthesis, in the plastid genomes of O. neapolitana as well as in other benthic Isochrysidales and Coccolithales species, putatively suggesting an evolutionary adaptation to benthic habitats. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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22 pages, 6015 KiB  
Article
Insights into Cellular Localization and Environmental Influences on the Toxicity of Marine Fish-Killing Flagellate, Heterosigma akashiwo
by Malihe Mehdizadeh Allaf and Charles G. Trick
Int. J. Mol. Sci. 2023, 24(12), 10333; https://doi.org/10.3390/ijms241210333 - 19 Jun 2023
Cited by 1 | Viewed by 949
Abstract
Heterosigma akashiwo is a unicellular microalga which can cause massive mortality in both wild and cultivated fish worldwide, resulting in substantial economic losses. Environmental parameters such as salinity, light, and temperature showed a significant effect on bloom initiation and the toxicity of H. [...] Read more.
Heterosigma akashiwo is a unicellular microalga which can cause massive mortality in both wild and cultivated fish worldwide, resulting in substantial economic losses. Environmental parameters such as salinity, light, and temperature showed a significant effect on bloom initiation and the toxicity of H. akashiwo. While in previous studies a one-factor-at-a-time (OFAT) approach was utilized, which only changes one variable at a time while keeping others constant, in the current study a more precise and effective design of experiment (DOE) approach, was used to investigate the simultaneous effect of three factors and their interactions. The study employed a central composite design (CCD) to investigate the effect of salinity, light intensity, and temperature on the toxicity, lipid, and protein production of H. akashiwo. A yeast cell assay was developed to assess toxicity, which offers rapid and convenient cytotoxicity measurements using a lower volume of samples compared to conventional methods using the whole organism. The obtained results showed that the optimum condition for toxicity of H. akashiwo was 25 °C, a salinity of 17.5, and a light intensity of 250 μmol photons m−2 s−1. The highest amount of lipid and protein was found at 25 °C, a salinity of 30, and a light intensity of 250 μmol photons m−2 s−1. Consequently, the combination of warm water mixing with lower salinity river input has the potential to enhance H. akashiwo toxicity, which aligns with environmental reports that establish a correlation between warm summers and extensive runoff conditions that indicate the greatest concern for aquaculture facilities. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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20 pages, 16903 KiB  
Article
Failure of Micractinium simplicissimum Phosphate Resilience upon Abrupt Re-Feeding of Its Phosphorus-Starved Cultures
by Elena Lobakova, Olga Gorelova, Irina Selyakh, Larisa Semenova, Pavel Scherbakov, Svetlana Vasilieva, Petr Zaytsev, Karina Shibzukhova, Olga Chivkunova, Olga Baulina and Alexei Solovchenko
Int. J. Mol. Sci. 2023, 24(10), 8484; https://doi.org/10.3390/ijms24108484 - 9 May 2023
Cited by 1 | Viewed by 1147
Abstract
Microalgae are naturally adapted to the fluctuating availability of phosphorus (P) to opportunistically uptake large amounts of inorganic phosphate (Pi) and safely store it in the cell as polyphosphate. Hence, many microalgal species are remarkably resilient to high concentrations of external [...] Read more.
Microalgae are naturally adapted to the fluctuating availability of phosphorus (P) to opportunistically uptake large amounts of inorganic phosphate (Pi) and safely store it in the cell as polyphosphate. Hence, many microalgal species are remarkably resilient to high concentrations of external Pi. Here, we report on an exception from this pattern comprised by a failure of the high Pi-resilience in strain Micractinium simplicissimum IPPAS C-2056 normally coping with very high Pi concentrations. This phenomenon occurred after the abrupt re-supplementation of Pi to the M. simplicissimum culture pre-starved of P. This was the case even if Pi was re-supplemented in a concentration far below the level toxic to the P-sufficient culture. We hypothesize that this effect can be mediated by a rapid formation of the potentially toxic short-chain polyphosphate following the mass influx of Pi into the P-starved cell. A possible reason for this is that the preceding P starvation impairs the capacity of the cell to convert the newly absorbed Pi into a “safe” storage form of long-chain polyphosphate. We believe that the findings of this study can help to avoid sudden culture crashes, and they are also of potential significance for the development of algae-based technologies for the efficient bioremoval of P from P-rich waste streams. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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19 pages, 7864 KiB  
Article
Characterization of Molecular Diversity and Organization of Phycobilisomes in Thermophilic Cyanobacteria
by Jie Tang, Huizhen Zhou, Dan Yao, Lianming Du and Maurycy Daroch
Int. J. Mol. Sci. 2023, 24(6), 5632; https://doi.org/10.3390/ijms24065632 - 15 Mar 2023
Cited by 3 | Viewed by 1628
Abstract
Thermophilic cyanobacteria are cosmopolitan and abundant in the thermal environment. Their light-harvesting complexes, phycobilisomes (PBS), are highly important in photosynthesis. To date, there is limited information on the PBS composition of thermophilic cyanobacteria whose habitats are challenging for survival. Herein, genome-based methods were [...] Read more.
Thermophilic cyanobacteria are cosmopolitan and abundant in the thermal environment. Their light-harvesting complexes, phycobilisomes (PBS), are highly important in photosynthesis. To date, there is limited information on the PBS composition of thermophilic cyanobacteria whose habitats are challenging for survival. Herein, genome-based methods were used to investigate the molecular components of PBS in 19 well-described thermophilic cyanobacteria. These cyanobacteria are from the genera Leptolyngbya, Leptothermofonsia, Ocullathermofonsia, Thermoleptolyngbya, Trichothermofonsia, Synechococcus, Thermostichus, and Thermosynechococcus. According to the phycobiliprotein (PBP) composition of the rods, two pigment types are observed in these thermophiles. The amino acid sequence analysis of different PBP subunits suggests several highly conserved cysteine residues in these thermophiles. Certain amino acid contents in the PBP of thermophiles are significantly higher than their mesophilic counterparts, highlighting the potential roles of specific substitutions of amino acid in the adaptive thermostability of light-harvesting complexes in thermophilic cyanobacteria. Genes encoding PBS linker polypeptides vary among the thermophiles. Intriguingly, motifs in linker apcE indicate a photoacclimation of a far-red light by Leptolyngbya JSC-1, Leptothermofonsia E412, and Ocullathermofonsia A174. The composition pattern of phycobilin lyases is consistent among the thermophiles, except for Thermostichus strains that have extra homologs of cpcE, cpcF, and cpcT. In addition, phylogenetic analyses of genes coding for PBPs, linkers, and lyases suggest extensive genetic diversity among these thermophiles, which is further discussed with the domain analyses. Moreover, comparative genomic analysis suggests different genomic distributions of PBS-related genes among the thermophiles, indicating probably various regulations of expression. In summary, the comparative analysis elucidates distinct molecular components and organization of PBS in thermophilic cyanobacteria. These results provide insights into the PBS components of thermophilic cyanobacteria and fundamental knowledge for future research regarding structures, functions, and photosynthetic improvement. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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17 pages, 3994 KiB  
Article
Genetic Diversity and Phylogeography of a Turf-Forming Cosmopolitan Marine Alga, Gelidium crinale (Gelidiales, Rhodo-Phyta)
by Ga Hun Boo, Antonella Bottalico, Line Le Gall and Hwan Su Yoon
Int. J. Mol. Sci. 2023, 24(6), 5263; https://doi.org/10.3390/ijms24065263 - 9 Mar 2023
Viewed by 1729
Abstract
Cosmopolitan species are rare in red algae, which have a low-dispersal capacity unless they are dispersed by human-mediated introductions. Gelidium crinale, a turf-forming red alga, has a widespread distribution in tropical and temperate waters. To decipher the genetic diversity and phylogeography of [...] Read more.
Cosmopolitan species are rare in red algae, which have a low-dispersal capacity unless they are dispersed by human-mediated introductions. Gelidium crinale, a turf-forming red alga, has a widespread distribution in tropical and temperate waters. To decipher the genetic diversity and phylogeography of G. crinale, we analyzed mitochondrial COI-5P and plastid rbcL sequences from collections in the Atlantic, Indian, and Pacific Oceans. Phylogenies of both markers statistically supported the monophyly of G. crinale, with a close relationship to G. americanum and G. calidum from the Western Atlantic. Based on the molecular analysis from these materials, Pterocladia heteroplatos from India is here merged with G. crinale. Phylogeny and TCS networks of COI-5P haplotypes revealed a geographic structure of five groups: (i) Atlantic-Mediterranean, (ii) Ionian, (iii) Asian, (iv) Adriatic-Ionian, and (v) Australasia-India-Tanzania-Easter Island. The most common ancestor of G. crinale likely diverged during the Pleistocene. The Bayesian Skyline Plots suggested the pre-LGM population expansion. Based on geographical structure, lineage-specific private haplotypes, the absence of shared haplotypes between lineages, and AMOVA, we propose that the cosmopolitan distribution of G. crinale has been shaped by Pleistocene relicts. The survival of the turf species under environmental stresses is briefly discussed. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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13 pages, 1176 KiB  
Article
Exploring the Physiological Multiplicity of Native Microalgae from the Ecuadorian Highland, Italian Lowland and Indoor Locations in Response to UV-B
by Thais Huarancca Reyes, Carolina Chiellini, Emilio Barozzi, Carla Sandoval, Cristina Echeverría and Lorenzo Guglielminetti
Int. J. Mol. Sci. 2023, 24(2), 1346; https://doi.org/10.3390/ijms24021346 - 10 Jan 2023
Cited by 2 | Viewed by 1411
Abstract
The differential effects of UV-B on the inhibition or activation of protective mechanisms to maintain cells photosynthetically active were investigated in native microalgae. Four strains were used, including two Chlorella sorokiniana strains, F4 and LG1, isolated from a Mediterranean inland swamp and a [...] Read more.
The differential effects of UV-B on the inhibition or activation of protective mechanisms to maintain cells photosynthetically active were investigated in native microalgae. Four strains were used, including two Chlorella sorokiniana strains, F4 and LG1, isolated from a Mediterranean inland swamp and a recycled cigarette butt’s substrate, respectively, and two isolates from an Ecuadorian highland lake related to Pectinodesmus pectinatus (PEC) and Ettlia pseudoalveolaris (ETI). Monocultures were exposed to acute UV-B (1.7 W m−2) over 18 h under controlled conditions. UV-B-untreated microalgae were used as the control. Comparative physiological responses, including photosynthetic pigments, non-enzymatic antioxidants, and chlorophyll a fluorescence, were evaluated at specific time points. Results showed that UV-B significantly compromised all the physiological parameters in F4, thereby resulting in the most UV-B-sensitive strain. Contrarily, UV-B exposure did not lead to changes in the PEC physiological traits, resulting in the best UV-B-resistant strain. This could be attributed to the acclimation to high light habitat, where maintaining a constitutive phenotype (at the photosynthetic level) is strategically advantageous. Differently, LG1 and ETI at 12 h of UV-B exposure showed different UV-B responses, which is probably related to acclimation, where in LG1, the pigments were recovered, and the antioxidants were still functioning, while in ETI, the accumulation of pigments and antioxidants was increased to avoid further photodamage. Consequently, the prolonged exposure in LG1 and ETI resulted in species-specific metabolic regulation (e.g., non-enzymatic antioxidants) in order to constrain full photoinhibition under acute UV-B. Full article
(This article belongs to the Special Issue Advances in Research of Algae, Cyanobacteria, and Phytoplankton)
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