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Liu J, Yu Q, Ye B, Zhu K, Yin J, Zheng T, Xu S, Sun Q, Li Y, Zuo Z. Programmed cell death of Chlamydomonas reinhardtii induced by three cyanobacterial volatiles β-ionone, limonene and longifolene. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:144539. [PMID: 33360449 DOI: 10.1016/j.scitotenv.2020.144539] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/22/2020] [Accepted: 12/12/2020] [Indexed: 06/12/2023]
Abstract
β-Ionone, limonene and longifolene are 3 main components in cyanobacterial volatile organic compounds, which are formed through different pathways and can poison and even kill other algae. To uncover their toxic mechanism from programmed cell death (PCD), the photosynthetic pigments, chlorophyll fluorescence, caspase-like activities, cell size, nuclear variations and DNA ladders were investigated in Chlamydomonas reinhardtii treated with β-ionone (0.2 mM), limonene (0.2 mM) and longifolene (0.4 mM) at lethal concentration during 24 h. In the treatments with the 3 compounds, the photosynthetic pigments in C. reinhardtii cells gradually degraded, and Fv/Fm gradually decreased and disappeared at 24 h, suggesting that the cell death might be a PCD, due to the physiological activities gradually disappearing. During the cell death, the activities of caspase-9-like and caspase-3-like significantly increased, with the highest at 1 h. With prolonging the treatment time, C. reinhardtii cells gradually shrank, and the nuclei concentrated firstly following by a broken process, with moving to the cell edge. For DNA, obvious ladders were detected at 1 h, and then they gradually degraded to fragments of 100-250 bp at 24 h. These hallmarks suggested that β-ionone, limonene and longifolene may poison other algae by inducing PCD.
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Affiliation(s)
- Jialu Liu
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China
| | - Qianpeng Yu
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China
| | - Bingqi Ye
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China
| | - Kaiqi Zhu
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China
| | - Jiawen Yin
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China
| | - Tiefeng Zheng
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China
| | - Sun Xu
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China
| | - Qing Sun
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China
| | - Yan Li
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China
| | - Zhaojiang Zuo
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China.
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Aguilera A, Klemenčič M, Sueldo DJ, Rzymski P, Giannuzzi L, Martin MV. Cell Death in Cyanobacteria: Current Understanding and Recommendations for a Consensus on Its Nomenclature. Front Microbiol 2021; 12:631654. [PMID: 33746925 PMCID: PMC7965980 DOI: 10.3389/fmicb.2021.631654] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 02/11/2021] [Indexed: 01/31/2023] Open
Abstract
Cyanobacteria are globally widespread photosynthetic prokaryotes and are major contributors to global biogeochemical cycles. One of the most critical processes determining cyanobacterial eco-physiology is cellular death. Evidence supports the existence of controlled cellular demise in cyanobacteria, and various forms of cell death have been described as a response to biotic and abiotic stresses. However, cell death research in this phylogenetic group is a relatively young field and understanding of the underlying mechanisms and molecular machinery underpinning this fundamental process remains largely elusive. Furthermore, no systematic classification of modes of cell death has yet been established for cyanobacteria. In this work, we analyzed the state of knowledge in the field of cyanobacterial cell death. Based on that, we propose unified criterion for the definition of accidental, regulated, and programmed forms of cell death in cyanobacteria based on molecular, biochemical, and morphologic aspects following the directions of the Nomenclature Committee on Cell Death (NCCD). With this, we aim to provide a guide to standardize the nomenclature related to this topic in a precise and consistent manner, which will facilitate further ecological, evolutionary, and applied research in the field of cyanobacterial cell death.
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Affiliation(s)
- Anabella Aguilera
- Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Kalmar, Sweden
| | - Marina Klemenčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Daniela J. Sueldo
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Piotr Rzymski
- Department of Environmental Medicine, Poznan University of Medical Sciences, Poznan´, Poland
- Integrated Science Association (ISA), Universal Scientific Education and Research Network (USERN), Poznan´, Poland
| | - Leda Giannuzzi
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Universidad Nacional de La Plata, La Plata, Argentina
- Área de Toxicología General, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - María Victoria Martin
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC-CONICET), Fundación para Investigaciones Biológicas Aplicadas (CIB-FIBA), Mar del Plata, Argentina
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Li B, Yin Y, Kang L, Feng L, Liu Y, Du Z, Tian Y, Zhang L. A review: Application of allelochemicals in water ecological restoration--algal inhibition. CHEMOSPHERE 2021; 267:128869. [PMID: 33218724 DOI: 10.1016/j.chemosphere.2020.128869] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/24/2020] [Accepted: 10/31/2020] [Indexed: 06/11/2023]
Abstract
Problems caused by harmful algal blooms have attracted worldwide attention due to their severe harm to aquatic ecosystems, prompting researchers to study applicable measures to inhibit the growth of algae. Allelochemicals, as secondary metabolites secreted by plants, have excellent biocompatibility, biodegradability, obvious algal inhibiting effect and little ecological harm, and have promising application prospect in the field of water ecological restoration. This review summarized the research progress of allelochemicals, including (i) definition, development, and classification, (ii) influencing factors and mechanism of algal inhibition, (iii) the preparation methods of algal inhibitors based on allelochemicals. The future research directions of allelochemicals sustained-released microspheres (SRMs) were also prospected. In the future, it is urgent to explore more efficient allelochemicals, to study the regulation mechanism of allelochemicals in natural water bodies, and to improve the preparation method of allelopathic algal suppressant. This paper proposed a feasible direction for the development of allelochemicals SRMs which exhibited certain guiding significance for their application in water ecological restoration.
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Affiliation(s)
- Benhang Li
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Ecoremediation, Beijing Forestry University, Beijing, 100083, China
| | - Yijun Yin
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Ecoremediation, Beijing Forestry University, Beijing, 100083, China
| | - Longfei Kang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Ecoremediation, Beijing Forestry University, Beijing, 100083, China
| | - Li Feng
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Ecoremediation, Beijing Forestry University, Beijing, 100083, China
| | - Yongze Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Ecoremediation, Beijing Forestry University, Beijing, 100083, China
| | - Ziwen Du
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Ecoremediation, Beijing Forestry University, Beijing, 100083, China
| | - Yajun Tian
- College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Liqiu Zhang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Ecoremediation, Beijing Forestry University, Beijing, 100083, China.
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Matilla AJ. Cellular oxidative stress in programmed cell death: focusing on chloroplastic 1O 2 and mitochondrial cytochrome-c release. JOURNAL OF PLANT RESEARCH 2021; 134:179-194. [PMID: 33569718 DOI: 10.1007/s10265-021-01259-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/28/2021] [Indexed: 06/12/2023]
Abstract
The programmed cell death (PCD) occurs when the targeted cells have fulfilled their task or under conditions as oxidative stress generated by ROS species. Thus, plants have to deal with the singlet oxygen 1O2 produced in chloroplasts. 1O2 is unlikely to act as a primary retrograde signal owing to its high reactivity and short half-life. In addition to its high toxicity, the 1O2 generated under an excess or low excitation energy might also act as a highly versatile signal triggering chloroplast-to-nucleus retrograde signaling (ChNRS) and nuclear reprogramming or cell death. Molecular and biochemical studies with the flu mutant, which accumulates protochlorophyllide in the dark, demonstrated that chloroplastic 1O2-driven EXECUTER-1 (EX1) and EX2 proteins are involved in the 1O2-dependent response. Both EX1 and EX2 are necessary for full suppression of 1O2-induced gene expression. That is, EXECUTER proteolysis via the ATP-dependent zinc protease (FtsH) is an integral part of 1O2-triggered retrograde signaling. The existence of at least two independent ChNRS involving EX1 and β-cyclocitral, and dihydroactinidiolide and OXI1, respectively, seem clear. Besides, this update also focuses on plant PCD and its relation with mitochondrial cytochrome-c (Cytc) release to cytosol. Changes in the dynamics and morphology of mitochondria were shown during the onset of cell death. The mitochondrial damage and translocation of Cytc may be one of the major causes of PCD triggering. Together, this current overview illustrates the complexity of the cellular response to oxidative stress development. A puzzle with the majority of its pieces still not placed.
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Affiliation(s)
- Angel J Matilla
- Departamento de Biología Funcional, Facultad de Farmacia, Universidad de Santiago de Compostela (USC), Campus Vida, 15782, Santiago de Compostela, A Coruña, Spain.
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Lema A S, Klemenčič M, Völlmy F, Altelaar M, Funk C. The Role of Pseudo-Orthocaspase (SyOC) of Synechocystis sp. PCC 6803 in Attenuating the Effect of Oxidative Stress. Front Microbiol 2021; 12:634366. [PMID: 33613507 PMCID: PMC7889975 DOI: 10.3389/fmicb.2021.634366] [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: 11/27/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022] Open
Abstract
Caspases are proteases, best known for their involvement in the execution of apoptosis-a subtype of programmed cell death, which occurs only in animals. These proteases are composed of two structural building blocks: a proteolytically active p20 domain and a regulatory p10 domain. Although structural homologs appear in representatives of all other organisms, their functional homology, i.e., cell death depending on their proteolytical activity, is still much disputed. Additionally, pseudo-caspases and pseudo-metacaspases, in which the catalytic histidine-cysteine dyad is substituted with non-proteolytic amino acid residues, were shown to be involved in cell death programs. Here, we present the involvement of a pseudo-orthocaspase (SyOC), a prokaryotic caspase-homolog lacking the p10 domain, in oxidative stress in the model cyanobacterium Synechocystis sp. PCC 6803. To study the in vivo impact of this pseudo-protease during oxidative stress its gene expression during exposure to H2O2 was monitored by RT-qPCR. Furthermore, a knock-out mutant lacking the pseudo-orthocaspase gene was designed, and its survival and growth rates were compared to wild type cells as well as its proteome. Deletion of SyOC led to cells with a higher tolerance toward oxidative stress, suggesting that this protein may be involved in a pro-death pathway.
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Affiliation(s)
- Saul Lema A
- Department of Chemistry, Umeå University, Umeå, Sweden
| | | | - Franziska Völlmy
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, Netherlands.,Netherlands Proteomics Centre, Utrecht, Netherlands
| | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, Netherlands.,Netherlands Proteomics Centre, Utrecht, Netherlands
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Discovery of Amoebicidal Compounds by Combining Computational and Experimental Approaches. Antimicrob Agents Chemother 2021; 65:AAC.01749-20. [PMID: 33229426 DOI: 10.1128/aac.01749-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 11/15/2020] [Indexed: 11/20/2022] Open
Abstract
Pathogenic and opportunistic free-living amoebae such as Acanthamoeba spp. can cause keratitis (Acanthamoeba keratitis [AK]), which may ultimately lead to permanent visual impairment or blindness. Acanthamoeba can also cause rare but usually fatal granulomatous amoebic encephalitis (GAE). Current therapeutic options for AK require a lengthy treatment with nonspecific drugs that are often associated with adverse effects. Recent developments in the field led us to target cAMP pathways, specifically phosphodiesterase. Guided by computational tools, we targeted the Acanthamoeba phosphodiesterase RegA. Computational studies led to the construction and validation of a homology model followed by a virtual screening protocol guided by induced-fit docking and chemical scaffold analysis using our medicinal and biological chemistry (MBC) chemical library. Subsequently, 18 virtual screening hits were prioritized for further testing in vitro against Acanthamoeba castellanii, identifying amoebicidal hits containing piperidine and urea imidazole cores. Promising activities were confirmed in the resistant cyst form of the amoeba and in additional clinical Acanthamoeba strains, increasing their therapeutic potential. Mechanism-of-action studies revealed that these compounds produce apoptosis through reactive oxygen species (ROS)-mediated mitochondrial damage. These chemical families show promise for further optimization to produce effective antiacanthamoebal drugs.
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57
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Ndhlovu A, Durand PM, Ramsey G. Programmed cell death as a black queen in microbial communities. Mol Ecol 2020; 30:1110-1119. [PMID: 33253458 DOI: 10.1111/mec.15757] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 11/25/2020] [Indexed: 01/20/2023]
Abstract
Programmed cell death (PCD) in unicellular organisms is in some instances an altruistic trait. When the beneficiaries are clones or close kin, kin selection theory may be used to explain the evolution of the trait, and when the trait evolves in groups of distantly related individuals, group or multilevel selection theory is invoked. In mixed microbial communities, the benefits are also available to unrelated taxa. But the evolutionary ecology of PCD in communities is poorly understood. Few hypotheses have been offered concerning the community role of PCD despite its far-reaching effects. The hypothesis we consider here is that PCD is a black queen. The Black Queen Hypothesis (BQH) outlines how public goods arising from a leaky function are exploited by other taxa in the community. Black Queen (BQ) traits are essential for community survival, but only some members bear the cost of possessing them, while others lose the trait In addition, BQ traits have been defined in terms of adaptive gene loss, and it is unknown whether this has occurred for PCD. Our conclusion is that PCD fulfils the two most important criteria of a BQ (leakiness and costliness), but that more empirical data are needed for assessing the remaining two criteria. In addition, we hold that for viewing PCD as a BQ, the original BQH needs to include social traits. Thus, despite some empirical and conceptual shortcomings, the BQH provides a helpful avenue for investigating PCD in microbial communities.
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Affiliation(s)
- Andrew Ndhlovu
- Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
| | - Pierre M Durand
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Grant Ramsey
- Institute of Philosophy, KU Leuven, Leuven, Belgium
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58
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Zhang E, Wu S, Cai W, Zeng J, Li J, Li G, Liu J. Validation of superior reference genes for qRT-PCR and Western blot analyses in marine Emiliania huxleyi-virus model system. J Appl Microbiol 2020; 131:257-271. [PMID: 33275816 DOI: 10.1111/jam.14958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/19/2020] [Accepted: 11/29/2020] [Indexed: 11/30/2022]
Abstract
AIMS To search for a set of reference genes for reliable gene expression analysis in the globally important marine coccolithophore Emiliania huxleyi-virus model system. METHODS AND RESULTS Fifteen housekeeping genes (CDKA, CYP15, EFG3, POLAI, RPL30, RPL13, SAMS, COX1, GPB1-2, HSP90, TUA, TUB, UBA1, CAM3 and GAPDH) were evaluated for their stability as potential reference genes for qRT-PCR using ΔCt, geNorm, NormFinder, Bestkeeper and RefFinder software. CDKA, TUA and TUB genes were tested as loading controls for Western blot in the same sample panel. Additionally, target genes associated with cell apoptosis, that is metacaspase genes, were applied to validate the selection of reference genes. The analysis results demonstrated that putative housekeeping genes exhibited significant variations in both mRNA and protein content during virus infection. After a comprehensive analysis with all the algorithms, CDKA and GAPDH were recommended as the most stable reference genes for E huxleyi virus (EhV) infection treatments. For Western blot, significant variation was seen for TUA and TUB, whereas CDKA was stably expressed, consistent with the results of qRT-PCR. CONCLUSIONS CDKA and GAPDH are the best choice for gene and protein expression analysis than the other candidate reference genes under EhV infection conditions. SIGNIFICANCE AND IMPACT OF THE STUDY The stable internal control genes identified in this work will help to improve the accuracy and reliability of gene expression analysis and gain insight into complex E. huxleyi-EhV interaction regulatory networks.
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Affiliation(s)
- E Zhang
- College of Food and Bioengineering, Jimei University, Xiamen, China
| | - S Wu
- College of Food and Bioengineering, Jimei University, Xiamen, China
| | - W Cai
- College of Food and Bioengineering, Jimei University, Xiamen, China
| | - J Zeng
- College of Food and Bioengineering, Jimei University, Xiamen, China
| | - J Li
- College of Food and Bioengineering, Jimei University, Xiamen, China
| | - G Li
- College of Food and Bioengineering, Jimei University, Xiamen, China
| | - J Liu
- College of Food and Bioengineering, Jimei University, Xiamen, China
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Expósito JR, Mejuto I, Catalá M. Detection of active cell death markers in rehydrated lichen thalli and the involvement of nitrogen monoxide (NO). Symbiosis 2020. [DOI: 10.1007/s13199-020-00727-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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60
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Teulière J, Bernard G, Bapteste E. The Distribution of Genes Associated With Regulated Cell Death Is Decoupled From the Mitochondrial Phenotypes Within Unicellular Eukaryotic Hosts. Front Cell Dev Biol 2020; 8:536389. [PMID: 33072737 PMCID: PMC7539657 DOI: 10.3389/fcell.2020.536389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 09/07/2020] [Indexed: 11/13/2022] Open
Abstract
Genetically regulated cell death (RCD) occurs in all domains of life. In eukaryotes, the evolutionary origin of the mitochondrion and of certain forms of RCD, in particular apoptosis, are thought to coincide, suggesting a central general role for mitochondria in cellular suicide. We tested this mitochondrial centrality hypothesis across a dataset of 67 species of protists, presenting 5 classes of mitochondrial phenotypes, including functional mitochondria, metabolically diversified mitochondria, functionally reduced mitochondria (Mitochondrion Related Organelle or MRO) and even complete absence of mitochondria. We investigated the distribution of genes associated with various forms of RCD. No homologs for described mammalian regulators of regulated necrosis could be identified in our set of 67 unicellular taxa. Protists with MRO and the secondarily a mitochondriate Monocercomonoides exilis display heterogeneous reductions of apoptosis gene sets with respect to typical mitochondriate protists. Remarkably, despite the total lack of mitochondria in M. exilis, apoptosis-associated genes could still be identified. These same species of protists with MRO and M. exilis harbored non-reduced autophagic cell death gene sets. Moreover, transiently multicellular protist taxa appeared enriched in apoptotic and autophagy associated genes compared to free-living protists. This analysis suggests that genes associated with apoptosis in animals and the presence of the mitochondria are significant yet non-essential biological components for RCD in protists. More generally, our results support the hypothesis of a selection for RCD, including both apoptosis and autophagy, as a developmental mechanism linked to multicellularity.
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Affiliation(s)
- Jérôme Teulière
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Museum National d'Histoire Naturelle, EPHE, Université des Antilles, Paris, France
| | - Guillaume Bernard
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Museum National d'Histoire Naturelle, EPHE, Université des Antilles, Paris, France
| | - Eric Bapteste
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Museum National d'Histoire Naturelle, EPHE, Université des Antilles, Paris, France
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Bhattacharjee S, Mishra AK. The tale of caspase homologues and their evolutionary outlook: deciphering programmed cell death in cyanobacteria. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:4639-4657. [PMID: 32369588 PMCID: PMC7475262 DOI: 10.1093/jxb/eraa213] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/28/2020] [Indexed: 06/11/2023]
Abstract
Programmed cell death (PCD), a genetically orchestrated mechanism of cellular demise, is paradoxically required to support life. As in lower eukaryotes and bacteria, PCD in cyanobacteria is poorly appreciated, despite recent biochemical and molecular evidence that supports its existence. Cyanobacterial PCD is an altruistic reaction to stressful conditions that significantly enhances genetic diversity and inclusive fitness of the population. Recent bioinformatic analysis has revealed an abundance of death-related proteases, i.e. orthocaspases (OCAs) and their mutated variants, in cyanobacteria, with the larger genomes of morphologically complex strains harbouring most of them. Sequence analysis has depicted crucial accessory domains along with the proteolytic p20-like sub-domain in OCAs, predicting their functional versatility. However, the cascades involved in sensing death signals, their transduction, and the downstream expression and activation of OCAs remain to be elucidated. Here, we provide a comprehensive description of the attempts to identify mechanisms of PCD and the existence and importance of OCAs based on in silico approaches. We also review the evolutionary and ecological significance of PCD in cyanobacteria. In the future, the analysis of cyanobacterial PCD will identify novel proteins that have varied functional roles in signalling cascades and also help in understanding the incipient mechanism of PCD morphotype(s) from where eukaryotic PCD might have originated.
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Affiliation(s)
- Samujjal Bhattacharjee
- Laboratory of Microbial Genetics, Department of Botany, Banaras Hindu University, Varanasi, India
| | - Arun Kumar Mishra
- Laboratory of Microbial Genetics, Department of Botany, Banaras Hindu University, Varanasi, India
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Zhou T, Cao H, Zheng J, Teng F, Wang X, Lou K, Zhang X, Tao Y. Suppression of water-bloom cyanobacterium Microcystis aeruginosa by algaecide hydrogen peroxide maximized through programmed cell death. JOURNAL OF HAZARDOUS MATERIALS 2020; 393:122394. [PMID: 32114135 DOI: 10.1016/j.jhazmat.2020.122394] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 02/22/2020] [Accepted: 02/22/2020] [Indexed: 06/10/2023]
Abstract
The global expansion and intensification of toxic cyanobacterial blooms require effective algaecides. Algaecides should be selective, effective, fast-acting, and ideally suppress cyanotoxin production. In this study, whether both maximum growth suppression and minimal toxin production can be simultaneously achieved was tested with a selective algaecide H2O2, through its ability to induce apoptosis-like programmed cell death (AL PCD) in a common bloom species Microcystis aeruginosa. Under doses of 1-15 mg L-1, non-monotonic dose-response suppression of H2O2 on M. aeruginosa were observed, where maximal cell death and minimal microcystin production both occurred at a moderate dose of 10 mg L-1 H2O2. Maximal cell death was indeed achieved through AL PCD, as revealed by integrated biochemical, structural, physiological and transcriptional evidence; transcriptional profile suggested AL PCD was mediated by mazEF and lexA systems. Higher H2O2 doses directly led to necrosis in M. aeruginosa, while lower doses only caused recoverable stress. The integrated data showed the choice between the two modes of cell death is determined by the intracellular energy state under stress. A model was proposed for suppressing M. aeruginosa with AL PCD or necrosis. H2O2 was demonstrated to simultaneously maximize the suppression of both growth and microcystin production through triggering AL PCD.
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Affiliation(s)
- Tingru Zhou
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China; Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China
| | - Huansheng Cao
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, 85287, USA.
| | - Jie Zheng
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China; Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Tsinghua Shenzhen International Graduate School, Tsinghua University, PR China
| | - Fei Teng
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China; Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China
| | - Xuejian Wang
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China; Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China
| | - Kai Lou
- Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Tsinghua Shenzhen International Graduate School, Tsinghua University, PR China
| | - Xihui Zhang
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China
| | - Yi Tao
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China; Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China.
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Zhao Y, Tang X, Qu F, Lv M, Liu Q, Li J, Li L, Zhang B, Zhao Y. ROS-mediated programmed cell death (PCD) of Thalassiosira pseudonana under the stress of BDE-47. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 262:114342. [PMID: 32179226 DOI: 10.1016/j.envpol.2020.114342] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/21/2020] [Accepted: 03/05/2020] [Indexed: 06/10/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are a series of highly persistent organic pollutants (POPs) ubiquitously distributed in marine environments. As key primary producers, microalgae are the start of PBDEs bioaccumulations and vulnerable to their toxicities. In order to deeply investigate the toxic mechanism of PBDEs on microalgal cells, the occurrence of programmed cell death (PCD) in a model diatom Thalassiosira pseudonana and its possible mediating mechanism were studied. The results indicated: cell death of T. pseudonana happened under the stress of BDE-47, which was proved to be PCD based on the correlations with three biochemical markers (DNA fragmentation, phosphatidylserine externalization and caspase activity) and three molecular markers [Metacaspase 2 gene (TpMC2), Death-associated protein gene (DAP3) and Death-specific protein 1 gene (TpDSP1)]; Furthermore, the changes of cellular ROS levels were correlated with the PCD markers and the dead cell rates, and the cell membrane and the chloroplast were identified as the major ROS production sites. Therefore, we concluded that PCD might be an important toxic mechanism of PBDEs on microalgal cells, and that chloroplast- and cell membrane-produced ROS was an important signaling molecule to mediate the PCD activation process. Our research firstly indicated microalgal PCD could be induced by PBDEs, and increased our knowledge of the toxic mechanisms by which POPs affect microalgal cells.
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Affiliation(s)
- Yirong Zhao
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Xuexi Tang
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| | - Fangyuan Qu
- First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, China
| | - Mengchen Lv
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Qian Liu
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Jun Li
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Luying Li
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Bihan Zhang
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China
| | - Yan Zhao
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.
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Multiple Roles of Diatom-Derived Oxylipins within Marine Environments and Their Potential Biotechnological Applications. Mar Drugs 2020; 18:md18070342. [PMID: 32629777 PMCID: PMC7401250 DOI: 10.3390/md18070342] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 02/07/2023] Open
Abstract
The chemical ecology of marine diatoms has been the subject of several studies in the last decades, due to the discovery of oxylipins with multiple simultaneous functions including roles in chemical defence (antipredator, allelopathic and antibacterial compounds) and/or cell-to-cell signalling. Diatoms represent a fundamental compartment of marine ecosystems because they contribute to about 45% of global primary production even if they represent only 1% of the Earth’s photosynthetic biomass. The discovery that they produce several toxic metabolites deriving from the oxidation of polyunsaturated fatty acids, known as oxylipins, has changed our perspectives about secondary metabolites shaping plant–plant and plant–animal interactions in the oceans. More recently, their possible biotechnological potential has been evaluated, with promising results on their potential as anticancer compounds. Here, we focus on some recent findings in this field obtained in the last decade, investigating the role of diatom oxylipins in cell-to-cell communication and their negative impact on marine biota. Moreover, we also explore and discuss the possible biotechnological applications of diatom oxylipins.
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Rzymski P, Klimaszyk P, Jurczak T, Poniedziałek B. Oxidative Stress, Programmed Cell Death and Microcystin Release in Microcystis aeruginosa in Response to Daphnia Grazers. Front Microbiol 2020; 11:1201. [PMID: 32625177 PMCID: PMC7311652 DOI: 10.3389/fmicb.2020.01201] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 05/12/2020] [Indexed: 01/01/2023] Open
Abstract
There is increasing evidence that programmed cell death (PCD) in cyanobacteria is triggered by oxidative stress and that it contributes to the survival of the cyanobacterial population such as Microcystis aeruginosa. At the same time, microcystins (MCs) released during cell lysis have been implicated in colony formation (enabled by the release of polysaccharides) in M. aeruginosa – a strategy that allows the effect of a stressor, including grazing to be avoided or decreased. This experimental research has explored whether extracts of Daphnia magna and Daphnia cucullata (corresponding to 5, 25, 50, and 100 individuals per liter) reveal the effect on the growth, intracellular reactive oxygen species (ROS) content, lipid peroxidation, PCD, MC-LR release, and bound exopolysaccharide (EPS) level in M. aeruginosa during 7 days of exposure. As demonstrated, extracts of both daphnids induced dose-dependent growth inhibition, increase in ROS levels, lipid peroxidation, and PCD. Moreover, the release of MC-LR and an increase in the bound EPS fraction were observed in treated cultures. Generally, the greatest effects were observed under the influence of D. magna extracts. The study indicates that grazer presence can potentially trigger a series of events in the Microcystis population, with cells undergoing oxidative stress-induced PCD associated with MC release, which in turn increases EPS production by intact cells. As argued, this strategy is likely to have evolved in response to abiotic stressors, since both PCD and synthesis of MC in cyanobacteria predate the metazoan lineage. Nevertheless, it may still provide a benefit for the survival of the MC-producing M. aeruginosa population under grazer pressure.
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Affiliation(s)
- Piotr Rzymski
- Department of Environmental Medicine, Poznan University of Medical Sciences, Poznan´, Poland
| | - Piotr Klimaszyk
- Department of Water Protection, Adam Mickiewicz University, Poznan´, Poland
| | - Tomasz Jurczak
- UNESCO Chair on Ecohydrology and Applied Ecology, University of Lodz, Łódz´, Poland
| | - Barbara Poniedziałek
- Department of Environmental Medicine, Poznan University of Medical Sciences, Poznan´, Poland
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66
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Vallesi A, Pucciarelli S, Buonanno F, Fontana A, Mangiagalli M. Bioactive molecules from protists: Perspectives in biotechnology. Eur J Protistol 2020; 75:125720. [PMID: 32569992 DOI: 10.1016/j.ejop.2020.125720] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 05/11/2020] [Accepted: 05/15/2020] [Indexed: 12/14/2022]
Abstract
For hundreds of years, mankind has benefited from the natural metabolic processes of microorganisms to obtain basic products such as fermented foods and alcoholic beverages. More recently, microorganisms have been exploited for the production of antibiotics, vitamins and enzymes to be used in medicine and chemical industries. Additionally, several modern drugs, including those for cancer therapy, are natural products or their derivatives. Protists are a still underexplored source of natural products potentially of interest for biotechnological and biomedical applications. This paper focuses on some examples of bioactive molecules from protists and associated bacteria and their possible use in biotechnology.
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Affiliation(s)
- Adriana Vallesi
- School of Biosciences and Veterinary Medicine, Università degli Studi di Camerino, Camerino (MC), Italy.
| | - Sandra Pucciarelli
- School of Biosciences and Veterinary Medicine, Università degli Studi di Camerino, Camerino (MC), Italy.
| | - Federico Buonanno
- Laboratory of Protistology and Biology Education, Department of E.C.H.T. Università degli Studi di Macerata, Macerata, Italy
| | - Angelo Fontana
- Bio-Organic Chemistry Unit, CNR-Institute of Biomolecular Chemistry, Pozzuoli, Napoli, Italy
| | - Marco Mangiagalli
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
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67
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Sun Q, Zhou M, Zuo Z. Toxic mechanism of eucalyptol and β-cyclocitral on Chlamydomonas reinhardtii by inducing programmed cell death. JOURNAL OF HAZARDOUS MATERIALS 2020; 389:121910. [PMID: 31879110 DOI: 10.1016/j.jhazmat.2019.121910] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 12/13/2019] [Accepted: 12/15/2019] [Indexed: 06/10/2023]
Abstract
Eucalyptol and β-cyclocitral are 2 main compounds in cyanobacterial volatile organic compounds and can poison other algae. To uncover the toxic mechanism of the 2 compounds, the cell growth, photosynthetic abilities, H2O2 production, caspase-like activities, nuclear variation and DNA laddering were investigated in Chlamydomonas reinhardtii treated with eucalyptol and β-cyclocitral. Eucalyptol at ≥ 0.1 mM and β-cyclocitral at ≥ 0.05 mM showed toxic effects on C. reinhardtii cells, and 1.2 mM eucalyptol and 0.4 mM β-cyclocitral killed the whole of the cells during 24 h. During the death process, the photosynthetic pigment gradually degraded, and Fv/Fm gradually declined, indicating that the death is not a necrosis due to the gradual disappearance of the physiological process. In the treatments with 1.2 mM eucalyptol and 0.4 mM β-cyclocitral, H2O2 content burst at 10 min and 30 min, respectively. Caspase-9-like and caspase-3-like were activated, and cell nucleuses concentrated firstly and then broke with prolonging the treatment time. Meanwhile, DNA showed laddering after 1 h, and was gradually cleaved by Ca2+-dependent endonucleases to mainly about 100-250 bp fragments. These hallmarks indicated that eucalyptol and β-cyclocitral may poison other algal cells by inducing programmed cell death triggered by the increased H2O2.
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Affiliation(s)
- Qing Sun
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, China
| | - Min Zhou
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, China
| | - Zhaojiang Zuo
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, China.
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68
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Zhang Y, Whalen JK. Production of the neurotoxin beta-N-methylamino-l-alanine may be triggered by agricultural nutrients: An emerging public health issue. WATER RESEARCH 2020; 170:115335. [PMID: 31812811 DOI: 10.1016/j.watres.2019.115335] [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: 07/21/2019] [Revised: 11/18/2019] [Accepted: 11/23/2019] [Indexed: 06/10/2023]
Abstract
Diverse taxa of cyanobacteria, dinoflagellates and diatoms produce β-N-methylamino-l-alanine (BMAA), a non-lipophilic, non-protein amino acid. BMAA is a neurotoxin in mammals. Its ingestion may be linked to human neurodegenerative diseases, namely the Amyotrophic lateral sclerosis/Parkinsonism dementia complex, based on epidemiological evidence from regions where cyanobacterial harmful algal blooms occur frequently. In controlled environments, cyanobacteria produce BMAA in response to ecophysiological cues such as nutrient availability, which may explain the elevated BMAA concentrations in freshwater environments that receive nutrient-rich agricultural runoff. This critical review paper summarizes what is known about how BMAA supports ecophysiological functions like nitrogen metabolism, photosyntheis and provides a competitive advantage to cyanobacteria in controlled and natural environments. We explain how BMAA production affected competitive interactions among the N2-fixing and non-N2-fixing populations in a freshwater cyanobacterial bloom that was stimulated by nutrient loading from the surrounding agricultural landscape. Better control of nutrients in agricultural fields is an excellent strategy to avoid the negative environmental consequences and public health concerns related to BMAA production.
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Affiliation(s)
- Yanyan Zhang
- McGill University, Department of Natural Resource Sciences, Macdonald Campus, 21, 111 Lakeshore Road, Ste-Anne-de, Bellevue, Quebec, H9X 3V9, Canada
| | - Joann K Whalen
- McGill University, Department of Natural Resource Sciences, Macdonald Campus, 21, 111 Lakeshore Road, Ste-Anne-de, Bellevue, Quebec, H9X 3V9, Canada.
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69
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Wang H, Chen F, Mi T, Liu Q, Yu Z, Zhen Y. Responses of Marine Diatom Skeletonema marinoi to Nutrient Deficiency: Programmed Cell Death. Appl Environ Microbiol 2020; 86:e02460-19. [PMID: 31757826 PMCID: PMC6974647 DOI: 10.1128/aem.02460-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 11/15/2019] [Indexed: 11/20/2022] Open
Abstract
Diatoms are important phytoplankton and contribute greatly to the primary productivity of marine ecosystems. Despite the ecological significance of diatoms and the importance of programmed cell death (PCD) in the fluctuation of diatom populations, little is known about the molecular mechanisms of PCD triggered by different nutrient stresses. Here we describe the physiological, morphological, biochemical, and molecular changes in response to low levels of nutrients in the ubiquitous diatom Skeletonema marinoi The levels of gene expression involved in oxidation resistance and PCD strongly increased upon nitrogen (N) or phosphorus (P) starvation. The enzymatic activity of caspase 3-like protein also increased. Differences in mRNA levels and protein activities were observed between the low-N and low-P treatments, suggesting that PCD could have a differential response to different nutrient stresses. When cultures were replete with N or P, the growth inhibition stopped. Meanwhile, the enzymatic activity of caspase 3-like protein and the number of cells with damaged membranes decreased. These results suggest that PCD is an important cell fate decision mechanism in the marine diatom S. marinoi Our results provide important insight into how diatoms adjust phenotypic and genotypic features of their cell-regulated death programs when stressed by nutrient limitations. Overall, this study could allow us to better understand the molecular mechanism behind the formation and termination of diatom blooms in the marine environment.IMPORTANCE Our study showed how the ubiquitous diatom S. marinoi responded to different nutrient limitations with PCD in terms of physiological, morphological, biochemical, and molecular characteristics. Some PCD-related genes (PDCD4, GOX, and HSP90) induced by N deficiency were relatively upregulated compared to those induced by P deficiency. In contrast, the expression of the TSG101 gene in S. marinoi showed a clear and constant increase during P limitation compared to N limitation. These findings suggest that PCD is a complex mechanism involving several different proteins. The systematic mRNA level investigations provide new insight into understanding the oxidative stress- and cell death-related functional genes of diatoms involved in the response to nutrient fluctuations (N or P stress) in the marine environment.
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Affiliation(s)
- Hualong Wang
- College of Marine Life Science, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland, USA
| | - Feng Chen
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland, USA
| | - Tiezhu Mi
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, China
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China
| | - Qian Liu
- College of Marine Life Science, Ocean University of China, Qingdao, China
| | - Zhigang Yu
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Key Laboratory of Marine Chemical Theory and Technology, Ministry of Education, Qingdao, China
| | - Yu Zhen
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, China
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China
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70
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Sima W, Hu M, He Q, Qiu Y, Lv Y, Dai L, Shao Q, Zhou T, Li H, Zhou M, Ai H, Zhan H. Regulation of nitrogen dynamics at the sediment–water interface during HAB degradation and subsequent reoccurrence. RSC Adv 2020; 10:13480-13488. [PMID: 35493021 PMCID: PMC9051457 DOI: 10.1039/c9ra10673a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 05/12/2020] [Accepted: 03/23/2020] [Indexed: 11/21/2022] Open
Abstract
The effects of harmful algal blooms (HABs) on nutrient dynamics have been extensively studied; however, the response of nitrogen to continuous HAB degradation and subsequent reoccurrence is not well understood. Here, a small-scale experiment was conducted to assess how nitrogen in the sediment–water interface (SWI) responds to HAB degradation and subsequent reoccurrence at different initial algal densities. The results showed that during the algae decomposition stage, the NH4+–N flux of the SWI remained positive but decreased with the increase in algal density from 3.5 × 107 to 2.3 × 108 cells per L, indicating that the sediment was the source of NH4+–N. In contrast, the deposit was a sink of NO3−–N. However, during the reoccurrence of HAB, the distribution of NH4+–N and NO3−–N fluxes was completely converted. Nitrogen flux analysis throughout algae decomposition and reoccurrence indicated that although the sediment acted as a sink of nitrogen, the flux was dependent on the initial algal density. Our results confirmed that algae decomposition and reoccurrence would greatly affect the nitrogen cycle of the SWI, during which dissolved oxygen (DO) and initial algal density dominated. This study is the first to show that the regulation of nitrogen flux and migration changes during continuous HAB decomposition and subsequent reoccurrence. The effects of harmful algal blooms (HABs) on nutrient dynamics have been extensively studied; however, the response of nitrogen to continuous HAB degradation and subsequent reoccurrence is not well understood.![]()
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71
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Programmed Cell Death-Like and Accompanying Release of Microcystin in Freshwater Bloom-Forming Cyanobacterium Microcystis: From Identification to Ecological Relevance. Toxins (Basel) 2019; 11:toxins11120706. [PMID: 31817272 PMCID: PMC6950475 DOI: 10.3390/toxins11120706] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 11/29/2019] [Accepted: 12/01/2019] [Indexed: 11/16/2022] Open
Abstract
Microcystis is the most common freshwater bloom-forming cyanobacteria. Its massive blooms not only adversely affect the functionality of aquatic ecosystems, but are also associated with the production of microcystins (MCs), a group of potent toxins that become a threat to public health when cell-bound MCs are significantly released from the dying Microcystis into the water column. Managing Microcystis blooms thus requires sufficient knowledge regarding both the cell death modes and the release of toxins. Recently, more and more studies have demonstrated the occurrence of programmed cell death-like (or apoptosis-like) events in laboratory and field samples of Microcystis. Apoptosis is a genetically controlled process that is essential for the development and survival of metazoa; however, it has been gradually realized to be an existing phenomenon playing important ecological roles in unicellular microorganisms. Here, we review the current progress and the existing knowledge gap regarding apoptosis-like death in Microcystis. Specifically, we focus first on the tools utilized to characterize the apoptosis-related biochemical and morphological features in Microcystis. We further outline various stressful stimuli that trigger the occurrence of apoptosis and discuss the potential mechanisms of apoptosis in Microcystis. We then propose a conceptual model to describe the functional coupling of apoptosis and MC in Microcystis. This model could be useful for understanding both roles of MC and apoptosis in this species. Lastly, we conclude the review by highlighting the current knowledge gap and considering the direction of future research. Overall, this review provides a recent update with respect to the knowledge of apoptosis in Microcystis and also offers a guide for future investigations of its ecology and survival strategies.
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72
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Synthesis of Zinc oxide nanoparticles from Marsdenia tenacissima inhibits the cell proliferation and induces apoptosis in laryngeal cancer cells (Hep-2). JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2019; 201:111624. [DOI: 10.1016/j.jphotobiol.2019.111624] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/05/2019] [Accepted: 09/10/2019] [Indexed: 01/09/2023]
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73
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Zimmerman AE, Howard-Varona C, Needham DM, John SG, Worden AZ, Sullivan MB, Waldbauer JR, Coleman ML. Metabolic and biogeochemical consequences of viral infection in aquatic ecosystems. Nat Rev Microbiol 2019; 18:21-34. [PMID: 31690825 DOI: 10.1038/s41579-019-0270-x] [Citation(s) in RCA: 158] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2019] [Indexed: 12/23/2022]
Abstract
Ecosystems are controlled by 'bottom-up' (resources) and 'top-down' (predation) forces. Viral infection is now recognized as a ubiquitous top-down control of microbial growth across ecosystems but, at the same time, cell death by viral predation influences, and is influenced by, resource availability. In this Review, we discuss recent advances in understanding the biogeochemical impact of viruses, focusing on how metabolic reprogramming of host cells during lytic viral infection alters the flow of energy and nutrients in aquatic ecosystems. Our synthesis revealed several emerging themes. First, viral infection transforms host metabolism, in part through virus-encoded metabolic genes; the functions performed by these genes appear to alleviate energetic and biosynthetic bottlenecks to viral production. Second, viral infection depends on the physiological state of the host cell and on environmental conditions, which are challenging to replicate in the laboratory. Last, metabolic reprogramming of infected cells and viral lysis alter nutrient cycling and carbon export in the oceans, although the net impacts remain uncertain. This Review highlights the need for understanding viral infection dynamics in realistic physiological and environmental contexts to better predict their biogeochemical consequences.
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Affiliation(s)
- Amy E Zimmerman
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL, USA
| | | | - David M Needham
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | - Seth G John
- Department of Earth Science, University of Southern California, Los Angeles, CA, USA
| | - Alexandra Z Worden
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA.,Ocean EcoSystems Biology Unit, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Matthew B Sullivan
- Department of Microbiology, Ohio State University, Columbus, OH, USA.,Department of Civil, Environmental and Geodetic Engineering, Ohio State University, Columbus, OH, USA
| | - Jacob R Waldbauer
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL, USA
| | - Maureen L Coleman
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL, USA.
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74
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de Carpentier F, Lemaire SD, Danon A. When Unity Is Strength: The Strategies Used by Chlamydomonas to Survive Environmental Stresses. Cells 2019; 8:E1307. [PMID: 31652831 PMCID: PMC6912462 DOI: 10.3390/cells8111307] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/18/2019] [Accepted: 10/21/2019] [Indexed: 12/21/2022] Open
Abstract
The unicellular green alga Chlamydomonas reinhardtii is a valuable model system to study a wide spectrum of scientific fields, including responses to environmental conditions. Most studies are performed under optimal growth conditions or under mild stress. However, when environmental conditions become harsher, the behavior of this unicellular alga is less well known. In this review we will show that despite being a unicellular organism, Chlamydomonas can survive very severe environmental conditions. To do so, and depending on the intensity of the stress, the strategies used by Chlamydomonas can range from acclimation to the formation of multicellular structures, or involve programmed cell death.
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Affiliation(s)
- Félix de Carpentier
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, 75005 Paris, France.
- Faculty of Sciences, Doctoral School of Plant Sciences, Université Paris-Sud, Paris-Saclay, 91400 Orsay, France.
| | - Stéphane D Lemaire
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, 75005 Paris, France.
| | - Antoine Danon
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, 75005 Paris, France.
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75
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Russo E, d'Ippolito G, Fontana A, Sarno D, D'Alelio D, Busseni G, Ianora A, von Elert E, Carotenuto Y. Density-dependent oxylipin production in natural diatom communities: possible implications for plankton dynamics. ISME JOURNAL 2019; 14:164-177. [PMID: 31611654 PMCID: PMC6908693 DOI: 10.1038/s41396-019-0518-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/30/2019] [Accepted: 09/04/2019] [Indexed: 01/17/2023]
Abstract
Oxylipins are important signal transduction lipoxygenase-derived products of fatty acids that regulate a variety of physiological and pathological processes in plants and animals. In marine diatoms, these molecules can be highly bioactive, impacting zooplankton grazers, bacteria and other phytoplankton. However, the ultimate cause for oxylipin production in diatoms is still poorly understood, from an evolutionary perspective. Here we analysed production of particulate linear oxygenated fatty acids (LOFAs, previously named non-volatile oxylipins) from natural phytoplankton collected weekly for 1 year. We demonstrate for the first time that diatoms are the main LOFA producers in natural phytoplankton assemblages. Interestingly, LOFA-per-cell production decreased with increasing diatom density and was not due to major changes in diatom community composition. An inverse relation was confirmed at a global scale by analysing diatom lipoxygenase unigenes and metagenomes from Tara Oceans datasets. A network analysis suggested that different LOFAs could contribute to modulate co-variations of different diatom taxa. Overall, we offer new insights in diatom chemical ecology, possibly explaining the evolution of oxylipin synthesis in diatoms.
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Affiliation(s)
- Ennio Russo
- Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology, Villa Comunale, 80121, Napoli, Italy
| | - Giuliana d'Ippolito
- Consiglio Nazionale delle Ricerche, Institute of Bio-molecular Chemistry, Via Campi Flegrei 34, 80078, Pozzuoli, Italy
| | - Angelo Fontana
- Consiglio Nazionale delle Ricerche, Institute of Bio-molecular Chemistry, Via Campi Flegrei 34, 80078, Pozzuoli, Italy
| | - Diana Sarno
- Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology, Villa Comunale, 80121, Napoli, Italy
| | - Domenico D'Alelio
- Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology, Villa Comunale, 80121, Napoli, Italy
| | - Greta Busseni
- Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology, Villa Comunale, 80121, Napoli, Italy
| | - Adrianna Ianora
- Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology, Villa Comunale, 80121, Napoli, Italy
| | - Eric von Elert
- Aquatic Chemical Ecology Group, Institute for Zoology, Universität zu Köln, Zülpicher Straße 47b, D-50674, Köln, Germany
| | - Ylenia Carotenuto
- Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology, Villa Comunale, 80121, Napoli, Italy.
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76
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Mata MT, Palma A, García-Gómez C, López-Parages M, Vázquez V, Cheng-Sánchez I, Sarabia F, López-Figueroa F, Jiménez C, Segovia M. Type II-Metacaspases are involved in cell stress but not in cell death in the unicellular green alga Dunaliella tertiolecta. MICROBIAL CELL 2019; 6:494-508. [PMID: 31799323 PMCID: PMC6859423 DOI: 10.15698/mic2019.11.696] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ultraviolet radiation (UVR; 280–400 nm) has a great impact on aquatic ecosystems by affecting ecophysiological and biogeochemical processes as a consequence of the global change scenario generated by anthropogenic activities. We studied the effect of PAR (P)+UVA (A)+UVB (B) i.e. PAB, on the molecular physiology of the unicellular green alga Dunaliella tertiolecta for six days. We assessed the relationship between the triggered UVR stress response and metacaspases and caspase-like (CL)activities, which are proteases denoted to participate in cell death (CD) in phytoplankton. UVR inhibited cell growth and in vivo chlorophyll a fluorescence but did not cause cell death. Western blot analyses reflected that Type-II metacaspases (MCs) are present and appear to be involved in UVR induced-cell stress but not in dark-induced CD in D. tertiolecta. Enzyme kinetics revealed that cleavage of the MCs-reporter substrates RVRR, QRR, GRR, LKR, HEK, and VLK was 10-fold higher than WEHD, DEVD, IETD, and LETD CLs-substrates. The lowest apparent Michaelis-Menten constants (KMap) corresponded to RVRRase (37.5 μM) indicating a high affinity by the RVRR substrate. The inhibition of enzymatic activities by using inhibitors with different target sites for hydrolyses demonstrated that from all of the R/ Kase activities only RVRRase was a potential candidate for being a metacaspase. In parallel, zymograms and peptide-mass fingerprinting analyses revealed the identities of such Rase activities suggesting an indirect evidence of possible natural physiological substrates of MCs. We present evidence of type II-MCs not being involved in CD in D. tertiolecta, but rather in survival strategies under the stressful irradiance conditions applied in this study.
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Affiliation(s)
- M Teresa Mata
- Department of Ecology, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain.,Present address: Antofagasta Bioinnovation Center (CBIA), Department of Biotechnology, Faculty of Marine Sciences and Biological Resources. University of Antofagasta, Antofagasta, Chile
| | - Armando Palma
- Department of Ecology, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain
| | - Candela García-Gómez
- Department of Ecology, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain.,Present address: Spanish Oceanographic Institute, Puerto Pesquero, 29640-Fuengirola, Málaga, Spain
| | - María López-Parages
- Department of Ecology, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain
| | - Víctor Vázquez
- Department of Ecology, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain
| | - Iván Cheng-Sánchez
- Department of Organic Chemistry, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain
| | - Francisco Sarabia
- Department of Organic Chemistry, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain
| | - Félix López-Figueroa
- Department of Ecology, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain
| | - Carlos Jiménez
- Department of Ecology, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain
| | - María Segovia
- Department of Ecology, Faculty of Sciences, University of Málaga, Blvd. Louis Pasteur s / n, 29071-Málaga, Spain
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77
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Daniel E, Weiss G, Murik O, Sukenik A, Lieman-Hurwitz J, Kaplan A. The response of Microcystis aeruginosa strain MGK to a single or two consecutive H 2 O 2 applications. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:621-629. [PMID: 31390482 DOI: 10.1111/1758-2229.12789] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 07/15/2019] [Accepted: 08/05/2019] [Indexed: 06/10/2023]
Abstract
Various approaches have been proposed to control/eliminate toxic Microcystis sp. blooms including H2 O2 treatments. Earlier studies showed that pre-exposure of various algae to oxidative stress induced massive cell death when cultures were exposed to an additional H2 O2 treatment. We examined the vulnerability of exponential and stationary-phase Microcystis sp. strain MGK cultures to single and double H2 O2 applications. Stationary cultures show a much higher ability to decompose H2 O2 than younger cultures. Nevertheless, they are more sensitive to an additional H2 O2 dose given 1-6 h after the first one. Transcript analyses following H2 O2 application showed a fast rise in glutathione peroxidase abundance (227-fold within an hour) followed by a steep decline thereafter. Other genes potentially engaged in oxidative stress were far less affected. Metabolic-related genes were downregulated after H2 O2 treatments. Among those examined, the transcript level of prk (encoding phosphoribulose kinase) was the slowest to recover in agreement with the decline in photosynthetic rate revealed by fluorescence measurements. Our findings shed light on the response of Microcystis MGK to oxidative stress suggesting that two consecutive H2 O2 applications of low concentrations are far more effective in controlling Microcystis sp. population than a single dose of a higher concentration.
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Affiliation(s)
- Einat Daniel
- Plants and Environmental Sciences, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 9190401, Israel
| | - Gad Weiss
- Plants and Environmental Sciences, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 9190401, Israel
| | - Omer Murik
- The Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, Israel
| | - Assaf Sukenik
- The Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, Israel
| | - Judy Lieman-Hurwitz
- Plants and Environmental Sciences, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 9190401, Israel
| | - Aaron Kaplan
- Plants and Environmental Sciences, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 9190401, Israel
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78
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Ursolic Acid Derivatives as Potential Agents Against Acanthamoeba Spp. Pathogens 2019; 8:pathogens8030130. [PMID: 31443577 PMCID: PMC6789456 DOI: 10.3390/pathogens8030130] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 08/20/2019] [Accepted: 08/21/2019] [Indexed: 11/17/2022] Open
Abstract
The current chemotherapy of Acanthamoeba keratitis relies on few drugs with low potential and limited efficacy, for all this there is an urgent need to identify new classes of anti-Acanthamoeba agents. In this regard, natural products play an important role in overcoming the current need and medicinal chemistry of natural products represents an attractive approach for the discovery and development of new agents. Ursolic acid, a natural pentacyclic triterpenoid compound, possesses a broad spectrum of activities including anti-Acanthamoeba. Herein, we report on the development by chemical transformation of an ursolic acid-based series of seven compounds (2-8), one of them reported for the first time. The structure-activity relationship (SAR) analysis of their anti-Acanthamoeba activity revealed that acylation/ether formation or oxidation enhances their biological profile, suggesting that the hydrophobic moiety contributes to activity, presumably by increasing the affinity and/or cell membrane permeability. These ursolic acid derivatives highlight the potential of this source as a good base for the development of novel therapeutic agents against Acanthamoeba infections.
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79
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Spungin D, Berman-Frank I. Assessment of Metacaspase Activity in Phytoplankton. Bio Protoc 2019; 9:e3341. [PMID: 33654845 DOI: 10.21769/bioprotoc.3341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 07/15/2019] [Accepted: 07/22/2019] [Indexed: 11/02/2022] Open
Abstract
Programmed cell death (PCD) is an irreversible, genetically-controlled form of cell suicide in which an endogenous biochemical pathway leads to morphological changes and ultimately, cellular demise. PCD is accompanied by de-novo protein synthesis of a family of proteases-"caspases" that are often used as a diagnostic marker of PCD. Although phytoplankton do not contain true caspases, caspase-like activity (hypothetical proteins with analogous activity) has been traditionally used as a diagnostic marker of PCD in marine phytoplankton. Increased caspase-like proteolytic activity was demonstrated when synthetic fluorogenic activity substrates specific for caspases (with an Asp at the P1 position) were applied upon PCD induction. Metacaspases, cysteine proteases, share structural properties with those of caspases, yet they are highly specific for Arg and Lys cleavage site at the P1 position implying that caspase specific substrates are not indicative of metacaspase catalytic activity. This method specifically tests direct metacaspase activity in phytoplankton by the cleavage of the fluorogenic metacaspase substrate Ac-VRPR-AMC. Metacaspase activity was tested by the addition of a metacaspase specific peptide that is conjugated to the fluorescent reporter molecule. The cleavage of the peptide by the metacaspase releases the fluorochrome that, when excited by light, emits fluorescence. The level of metacaspase enzymatic activity in the cell lysate is directly proportional to the fluorescence signal detected. The use of specific standards in this test enables the quantification of the fluorescence results. This assay directly allows monitoring the metacaspase cleavage products and thereby tracing evidence for programmed cell death.
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Affiliation(s)
- Dina Spungin
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Ilana Berman-Frank
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
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80
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Hill LJ, Paradas WC, Willemes MJ, Pereira MG, Salomon PS, Mariath R, Moura RL, Atella GC, Farina M, Amado-Filho GM, Salgado LT. Acidification-induced cellular changes in Symbiodinium isolated from Mussismilia braziliensis. PLoS One 2019; 14:e0220130. [PMID: 31381568 PMCID: PMC6681953 DOI: 10.1371/journal.pone.0220130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 07/09/2019] [Indexed: 01/27/2023] Open
Abstract
Dinoflagellates from the Symbiodiniaceae family and corals have an ecologically important endosymbiotic relationship. Scleractinian corals cannot survive for long periods without their symbionts. These algae, also known as zooxanthellae, on the other hand, thrives outside the coral cells. The free-living populations of zooxanthellae are essential for the resilience of the coral to environmental stressors such as temperature anomalies and ocean acidification. Yet, little is known about how ocean acidification may affect the free-living zooxanthellae. In this study we aimed to test morphological, physiological and biochemical responses of zooxanthellae from the Symbiodinium genus isolated from the coral Mussismilia braziliensis, endemic to the Brazilian coast, to acidification led by increased atmospheric CO2. We tested whether photosynthetic yield, cell ultrastructure, cell density and lipid profile would change after up to 16 days of exposure to pH 7.5 in an atmospheric pCO2 of 1633 μatm. Photosynthetic yield and cell density were negatively affected and chloroplasts showed vesiculated thylakoids, indicating morphological damage. Moreover, Symbiodinium fatty acid profile drastically changed in acidified condition, showing lower polyunsaturated fatty acids and higher saturated fatty acids contents, when compared to the control, non-acidified condition. These results show that seawater acidification as an only stressor causes significant changes in the physiology, biochemistry and ultrastructure of free-living Symbiodinium.
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Affiliation(s)
- Lilian J Hill
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Wladimir C Paradas
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Maria Julia Willemes
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Miria G Pereira
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Paulo S Salomon
- Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Rodrigo Mariath
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rodrigo L Moura
- Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Georgia C Atella
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Marcos Farina
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Gilberto M Amado-Filho
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leonardo T Salgado
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil
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81
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Vostinar AE, Goldsby HJ, Ofria C. Suicidal selection: Programmed cell death can evolve in unicellular organisms due solely to kin selection. Ecol Evol 2019; 9:9129-9136. [PMID: 31463010 PMCID: PMC6706235 DOI: 10.1002/ece3.5460] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/07/2019] [Accepted: 06/17/2019] [Indexed: 01/28/2023] Open
Abstract
ABSTRACT Unicellular organisms can engage in a process by which a cell purposefully destroys itself, termed programmed cell death (PCD). While it is clear that the death of specific cells within a multicellular organism could increase inclusive fitness (e.g., during development), the origin of PCD in unicellular organisms is less obvious. Kin selection has been shown to help maintain instances of PCD in existing populations of unicellular organisms; however, competing hypotheses exist about whether additional factors are necessary to explain its origin. Those factors could include an environmental shift that causes latent PCD to be expressed, PCD hitchhiking on a large beneficial mutation, and PCD being simply a common pathology. Here, we present results using an artificial life model to demonstrate that kin selection can, in fact, be sufficient to give rise to PCD in unicellular organisms. Furthermore, when benefits to kin are direct-that is, resources provided to nearby kin-PCD is more beneficial than when benefits are indirect-that is, nonkin are injured, thus increasing the relative amount of resources for kin. Finally, when considering how strict organisms are in determining kin or nonkin (in terms of mutations), direct benefits are viable in a narrower range than indirect benefits. OPEN RESEARCH BADGES This article has been awarded Open Data and Open Materials Badges. All materials and data are publicly accessible via the Open Science Framework at https://github.com/anyaevostinar/SuicidalAltruismDissertation/tree/master/LongTerm.
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82
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Mizrachi A, Graff van Creveld S, Shapiro OH, Rosenwasser S, Vardi A. Light-dependent single-cell heterogeneity in the chloroplast redox state regulates cell fate in a marine diatom. eLife 2019; 8:47732. [PMID: 31232691 PMCID: PMC6682412 DOI: 10.7554/elife.47732] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/18/2019] [Indexed: 12/14/2022] Open
Abstract
Diatoms are photosynthetic microorganisms of great ecological and biogeochemical importance, forming vast blooms in aquatic ecosystems. However, we are still lacking fundamental understanding of how individual cells sense and respond to diverse stress conditions, and what acclimation strategies are employed during bloom dynamics. We investigated cellular responses to environmental stress at the single-cell level using the redox sensor roGFP targeted to various organelles in the diatom Phaeodactylum tricornutum. We detected cell-to-cell variability using flow cytometry cell sorting and a microfluidics system for live imaging of oxidation dynamics. Chloroplast-targeted roGFP exhibited a light-dependent, bi-stable oxidation pattern in response to H2O2 and high light, revealing distinct subpopulations of sensitive oxidized cells and resilient reduced cells. Early oxidation in the chloroplast preceded commitment to cell death, and can be used for sensing stress cues and regulating cell fate. We propose that light-dependent metabolic heterogeneity regulates diatoms’ sensitivity to environmental stressors in the ocean. Microscopic algae, such as diatoms, are widely spread throughout the oceans, and are responsible for half of the oxygen we breathe. At certain times of the year these algae grow very rapidly to form large “blooms” that can be detected by satellites in space. These blooms are generally short-lived because the algae are either eaten by other marine organisms, run out of nutrients, or die as a result of being infected by viruses or bacteria. However, some diatom cells survive the end of the bloom and go on to generate new blooms in the future, but it is still not clear how. As the bloom collapses, diatoms experience many stressful conditions which can cause active molecules known as reactive oxygen species, or ROS for short, to accumulate inside cells. Normally growing cells also produce low amounts of ROS, which regulate various processes that are important for maintaining a cell’s health. However, high amounts of ROS can cause damage, which may lead to a cell’s death. Now, Mizrachi et al. investigated why some algae survive while others die in response to stressful conditions, focusing on the amount of ROS that accumulates within the diatom Phaeodactylum tricornutum. Laboratory experiments showed that individual cells of P. tricornutum respond differently to environmental stress, forming two distinct groups of either sensitive or resilient cells. Sensitive cells accumulated high levels of ROS within a cell compartment known as the chloroplast and eventually died. Whereas resilient cells were able to maintain low levels of ROS in the chloroplast and survived long after the other cells perished. Populations of genetically identical diatom cells also formed distinct groups of sensitive and resilient cells, demonstrating that these two opposing reactions to stress are not caused by genetic differences between cells. Lastly, Mizrachi et al. showed that how diatoms acclimate to stress depends on the amount of light they are exposed to. When in the dark, all cells became sensitive to oxidative stress, without forming distinct groups. But, when exposed to strong light that mimics the ocean surface, cells formed distinct groups within the population. This suggests that light regulates how susceptible these microscopic algae are to environmental stress. The different responses within a population may serve as a “bet-hedging” strategy, enabling at least some of the cells to survive unpredicted stressful conditions. The next challenge will be to find out whether algae growing in the oceans also use the same strategy and investigate what impact this has on diatom blooms.
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Affiliation(s)
- Avia Mizrachi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Shiri Graff van Creveld
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Orr H Shapiro
- Department of Food Quality and Safety, Institute of Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel
| | - Shilo Rosenwasser
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel.,The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Assaf Vardi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
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83
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Zhu J, Yu Z, He L, Cao X, Ji H, Song X. Physiological response dynamics of the brown tide organism Aureococcus anophagefferens treated with modified clay. HARMFUL ALGAE 2019; 86:1-9. [PMID: 31358268 DOI: 10.1016/j.hal.2019.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 03/21/2019] [Accepted: 04/15/2019] [Indexed: 06/10/2023]
Abstract
On the basis of experiences in mitigating harmful algal blooms (HABs) with modified clay (MC), a bloom does not continue after the dispersal of the MC, even though the density of the residual cells in the water remains as high as 20-30% of the initial cell density. This interesting phenomenon indicates that in addition to flocculation, MC has additional mechanisms of HAB control. Here, Aureococcus anophagefferens was selected as a model organism to study the physiological response dynamics of residual cells treated with MC, and RT-qPCR was used to measure the differential expression of 40 genes involved in anti-oxidation, photosynthesis, phospholipid synthesis, programmed cell death and cell proliferation at five time points. The results showed that every functional gene category exhibited a "V" shaped pattern with a turning point. It was reflected that there were two processes for MC inhibiting the growth of residual cells. One is the oxidative stress process (OSP) caused by ineffective collision with MC, whose effect weakened gradually; another is the programmed cell death process (PCDP) caused by the lysis of damaged residual cells, whose effect enhanced two days after MC treatment. In addition, the scanning electron micrographs verified that some of the residual cells were deformed or even lysed. Combined with the effects of OSP and PCDP in dynamics, the growth of residual cells was inhibited and was followed by gradual bloom disappearance. This study further elucidates the mechanism of MC controlling HABs at the molecular level and enable a more comprehensive understanding of HAB mitigation using MC.
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Affiliation(s)
- Jianan Zhu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Functional Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Zhiming Yu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Functional Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Liyan He
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Functional Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Xihua Cao
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Functional Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Hena Ji
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Functional Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Xiuxian Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Functional Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
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84
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Zhou DR, Eid R, Miller KA, Boucher E, Mandato CA, Greenwood MT. Intracellular second messengers mediate stress inducible hormesis and Programmed Cell Death: A review. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:773-792. [DOI: 10.1016/j.bbamcr.2019.01.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 01/25/2019] [Accepted: 01/29/2019] [Indexed: 12/11/2022]
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85
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Zhou DR, Eid R, Boucher E, Miller KA, Mandato CA, Greenwood MT. Stress is an agonist for the induction of programmed cell death: A review. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:699-712. [DOI: 10.1016/j.bbamcr.2018.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/17/2018] [Accepted: 12/01/2018] [Indexed: 02/07/2023]
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86
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Bramucci AR, Case RJ. Phaeobacter inhibens induces apoptosis-like programmed cell death in calcifying Emiliania huxleyi. Sci Rep 2019; 9:5215. [PMID: 30894549 PMCID: PMC6426857 DOI: 10.1038/s41598-018-36847-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 11/28/2018] [Indexed: 11/30/2022] Open
Abstract
The model coccolithophore, Emiliania huxleyi, forms expansive blooms dominated by the calcifying cell type, which produce calcite scales called coccoliths. Blooms last several weeks, after which the calcified algal cells rapidly die, descending into the deep ocean. E. huxleyi bloom collapse is attributed to E. huxleyi viruses (EhVs) that infect and kill calcifying cells, while other E. huxleyi pathogens, such as bacteria belonging to the roseobacter clade, are overlooked. EhVs kill calcifying E. huxleyi by inducing production of bioactive viral-glycosphingolipids (vGSLs), which trigger algal programmed cell death (PCD). The roseobacter Phaeobacter inhibens was recently shown to interact with and kill the calcifying cell type of E. huxleyi, but the mechanism of algal death remains unelucidated. Here we demonstrate that P. inhibens kills calcifying E. huxleyi by inducing a highly specific type of PCD called apoptosis-like-PCD (AL-PCD). Host death can successfully be abolished in the presence of a pan-caspase inhibitor, which prevents the activation of caspase-like molecules. This finding differentiates P. inhibens and EhV pathogenesis of E. huxleyi, by demonstrating that bacterial-induced AL-PCD requires active caspase-like molecules, while the viral pathogen does not. This is the first demonstration of a bacterium inducing AL-PCD in an algal host as a killing mechanism.
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Affiliation(s)
- Anna R Bramucci
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada
| | - Rebecca J Case
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada.
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87
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Spungin D, Bidle KD, Berman-Frank I. Metacaspase involvement in programmed cell death of the marine cyanobacteriumTrichodesmium. Environ Microbiol 2019; 21:667-681. [DOI: 10.1111/1462-2920.14512] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 12/19/2018] [Indexed: 01/09/2023]
Affiliation(s)
- Dina Spungin
- The Mina and Everard Goodman Faculty of Life Sciences; Bar-Ilan University; Ramat-Gan, 5290002 Israel
| | - Kay D. Bidle
- Department of Marine and Coastal Sciences; Rutgers University; New Brunswick NJ USA
| | - Ilana Berman-Frank
- The Mina and Everard Goodman Faculty of Life Sciences; Bar-Ilan University; Ramat-Gan, 5290002 Israel
- Department of Marine Biology; Leon H. Charney School of Marine Sciences, University of Haifa; Haifa Israel
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Chen Y, Weng Y, Zhou M, Meng Y, Liu J, Yang L, Zuo Z. Linalool- and α-terpineol-induced programmed cell death in Chlamydomonas reinhardtii. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 167:435-440. [PMID: 30368137 DOI: 10.1016/j.ecoenv.2018.10.062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/14/2018] [Accepted: 10/16/2018] [Indexed: 06/08/2023]
Abstract
Plant allelochemicals effectively inhibit and/ or control algal growth, and have potential to use as algaecide. To uncover the lethal mechanism of 2 anti-algal compounds linalool and α-terpineol identified from Cinnamomum camphora extracts, and promote their development as algaecide, the H2O2 production, photosynthetic abilities, caspase-like activities, nuclear changes and DNA degradation were investigated in Chlamydomonas reinhardtii treated with the 2 compounds. H2O2 content burst in linalool treatment at 0.5 h and in α-terpineol treatment at 1 h, with increases of 2.7 folds and 1.3 folds, respectively, compared to that at 0 h. The photosynthetic pigments gradually degraded, and Fv/Fm gradually declined to zero, indicating that the cell death was not a necrosis due to the gradual disappearance of physiological process. In C. reinhardtii cells, the caspase-9-like and caspase-3-like were activated in the treatments with the 2 compounds for 1 h. With prolonging the treatment time, the fluorescent intensity of the cell nucleuses stained by DAPI gradually enhanced and then faded, and the genomic DNA isolated from the cells gradually degraded. These hallmarks indicated that the death of C. reinhardtii cells in linalool and α-terpineol treatments was a programmed cell death (PCD) triggered by the increased reactive oxygen species (ROS). Compared to α-terpineol treatment, linalool treatment showed stronger promoting effects on PCD at the same time point, which may be caused by the higher ROS content inducing higher caspase-9-like and caspase-3-like activities in a short time.
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Affiliation(s)
- Yueting Chen
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Yuanyuan Weng
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Min Zhou
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Yiyu Meng
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Jialu Liu
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Lin Yang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Zhaojiang Zuo
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China.
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Ross C, Warhurst BC, Brown A, Huff C, Ochrietor JD. Mesohaline conditions represent the threshold for oxidative stress, cell death and toxin release in the cyanobacterium Microcystis aeruginosa. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 206:203-211. [PMID: 30500607 DOI: 10.1016/j.aquatox.2018.11.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 06/09/2023]
Abstract
As aquatic ecosystems become increasingly affected by hydrologic alterations, drought and sea level rise a need exists to better understand the biological effects of elevated salinity on toxigenic cyanobacteria such as Microcystis aeruginosa. This study investigated the impacts of oligohaline/low mesohaline conditions and exposure time on selected physiological and biochemical responses in M. aeruginosa including cell viability, oxidative stress, antioxidant responses, in addition to microcystin synthesis and release into the surrounding environment. M. aeruginosa was able to grow in most test salinity treatments (1.4-10 ppt), as supported by cell abundance data and chlorophyll-a (chl-a) concentrations. Physiological data showed that after certain salinity thresholds (∼7ppt) were surpassed, salt stress had cascading effects, such as increased ROS production and lipid peroxidation, potentiating the decline in cellular viability. Furthermore, elevated salinity induced oxidative stress which was concomitant with a decrease in cell abundance, chl-a concentration and photochemical efficiency in the 7-10 ppt treatments. M. aeruginosa did not synthesize microcystins (MCs) in response to increased saline conditions, and mcy-D expression was not correlated with either salinity treatment or extracellular MC concentrations, indicating that salinity stress could inhibit toxin production and that released toxins were likely synthesized prior to exposure. Additionally, extracellular MC concentrations were not correlated with decreased cellular integrity, as evidenced by SYTOX analyses, suggesting that toxins may be released through mechanisms other than cellular lysis. Results from this study support that M. aeruginosa can survive with limited negative impacts to cellular structure and function up to a certain threshold between 7-10 ppt. However, after these thresholds are surpassed, there is radical decline in cell health and viability leading to toxin release. This work underscores the importance of understanding the balance between ROS production and antioxidant capacities when assessing the fate of M. aeruginosa under mesohaline conditions.
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Affiliation(s)
- Cliff Ross
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA.
| | - B Christopher Warhurst
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA
| | - Amber Brown
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA
| | - Chase Huff
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA
| | - Judith D Ochrietor
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA
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90
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A simulation study on how the resource competition and anti-predator cooperation impact the motile-phytoplankton groups’ formation under predation stress. Ecol Modell 2019. [DOI: 10.1016/j.ecolmodel.2018.10.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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91
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92
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The chemical cue tetrabromopyrrole induces rapid cellular stress and mortality in phytoplankton. Sci Rep 2018; 8:15498. [PMID: 30341338 PMCID: PMC6195506 DOI: 10.1038/s41598-018-33945-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/04/2018] [Indexed: 02/08/2023] Open
Abstract
Eukaryotic phytoplankton contribute to the flow of elements through marine food webs, biogeochemical cycles, and Earth's climate. Therefore, how phytoplankton die is a critical determinate of the flow and fate of nutrients. While heterotroph grazing and viral infection contribute to phytoplankton mortality, recent evidence suggests that bacteria-derived cues also control phytoplankton lysis. Here, we report exposure to nanomolar concentrations of 2,3,4,5-tetrabromopyrrole (TBP), a brominated chemical cue synthesized by marine γ-proteobacteria, resulted in mortality of seven phylogenetically-diverse phytoplankton species. A comparison of nine compounds of marine-origin containing a range of cyclic moieties and halogenation indicated that both a single pyrrole ring and increased bromination were most lethal to the coccolithophore, Emiliania huxleyi. TBP also rapidly induced the production of reactive oxygen species and the release of intracellular calcium stores, both of which can trigger the activation of cellular death pathways. Mining of the Ocean Gene Atlas indicated that TBP biosynthetic machinery is globally distributed throughout the water column in coastal areas. These findings suggest that bacterial cues play multiple functions in regulating phytoplankton communities by inducing biochemical changes associated with cellular death. Chemically-induced lysis by bacterial infochemicals is yet another variable that must be considered when modeling oceanic nutrient dynamics.
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93
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Lee H, Lee DG. Arenicin-1-induced apoptosis-like response requires RecA activation and hydrogen peroxide against Escherichia coli. Curr Genet 2018; 65:167-177. [DOI: 10.1007/s00294-018-0855-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 06/05/2018] [Accepted: 06/06/2018] [Indexed: 12/25/2022]
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94
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Gallo C, Nuzzo G, d'Ippolito G, Manzo E, Sardo A, Fontana A. Sterol Sulfates and Sulfotransferases in Marine Diatoms. Methods Enzymol 2018; 605:101-138. [PMID: 29909823 DOI: 10.1016/bs.mie.2018.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sterol sulfates are widely occurring molecules in marine organisms. Their importance has been so far underestimated although many of these compounds are crucial mediators of physiological and ecological functions in other organisms. Biosynthesis of sterol sulfates is controlled by cytosolic sulfotransferases (SULTs), a varied family of enzymes that catalyze the transfer of a sulfo residue (-SO3H) from the universal donor 3'-phosphoadenosine-5'-phosphosulfate to the hydroxyl function at C-3 of the steroid skeleton. The absence of molecular tools has been the main impediment to the development of a biosynthetic study of this class of compounds in marine organisms. In fact, there is very limited information about these enzymes in marine environments. SULT activity has, however, been reported in several marine species, and, recently, the production of sterol sulfates has been linked to the control of growth in marine diatoms. In this chapter, we describe methods for the study of sterol sulfates in this lineage of marine microalgae. The main aim is to provide the tools useful to deal with the biosynthesis and regulation of these compounds and to circumvent the bottleneck of the lack of molecular information. The protocols have been designed for marine diatoms, but most of the procedures can be used for other marine organisms.
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Affiliation(s)
- Carmela Gallo
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy
| | - Genoveffa Nuzzo
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy
| | - Giuliana d'Ippolito
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy.
| | - Emiliano Manzo
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy
| | - Angela Sardo
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy
| | - Angelo Fontana
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy.
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Poirier I, Pallud M, Kuhn L, Hammann P, Demortière A, Jamali A, Chicher J, Caplat C, Gallon RK, Bertrand M. Toxicological effects of CdSe nanocrystals on the marine diatom Phaeodactylum tricornutum: The first mass spectrometry-based proteomic approach. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 152:78-90. [PMID: 29407785 DOI: 10.1016/j.ecoenv.2018.01.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/17/2018] [Accepted: 01/19/2018] [Indexed: 06/07/2023]
Abstract
UNLABELLED In the marine environment, benthic diatoms from estuarine and coastal sediments are among the first targets of nanoparticle pollution whose potential toxicity on marine organisms is still largely unknown. It is therefore relevant to improve our knowledge of interactions between these new pollutants and microalgae, the key players in the control of marine resources. In this study, the response of P. tricornutum to CdSe nanocrystals (CdSe NPs) of 5 nm (NP5) and 12 nm (NP12) in diameter was evaluated through microscopic, physiological, biochemical and proteomic approaches. NP5 and NP12 affected cell growth but oxygen production was only slightly decreased by NP5 after 1-d incubation time. In our experimental conditions, a high CdSe NP dissolution was observed during the first day of culture, leading to Cd bioaccumulation and oxidative stress, particularly with NP12. However, after a 7-day incubation time, proteomic analysis highlighted that P. tricornutum responded to CdSe NP toxicity by regulating numerous proteins involved in protection against oxidative stress, cellular redox homeostasis, Ca2+ regulation and signalling, S-nitrosylation and S-glutathionylation processes and cell damage repair. These proteome changes allowed algae cells to regulate their intracellular ROS level in contaminated cultures. P. tricornutum was also capable to control its intracellular Cd concentration at a sufficiently low level to preserve its growth. To our knowledge, this is the first work allowing the identification of proteins differentially expressed by P. tricornutum subjected to NPs and thus the understanding of some molecular pathways involved in its cellular response to nanoparticles. SIGNIFICANCE The microalgae play a key role in the control of marine resources. Moreover, they produce 50% of the atmospheric oxygen. CdSe NPs are extensively used in the industry of renewable energies and it is regrettably expected that these pollutants will sometime soon appear in the marine environment through surface runoff, urban effluents and rivers. Since estuarine and coastal sediments concentrate pollutants, benthic microalgae which live in superficial sediments will be among the first targets of nanoparticle pollution. Thus, it is relevant to improve our knowledge of interactions between diatoms and nanoparticles. Proteomics is a powerful tool for understanding the molecular mechanisms triggered by nanoparticle exposure, and our study is the first one to use this tool to identify proteins differentially expressed by P. tricornutum subjected to CdSe nanocrystals. This work is fundamental to improve our knowledge about the defence mechanisms developed by algae cells to counteract damage caused by CdSe NPs.
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Affiliation(s)
- Isabelle Poirier
- Institut National des Sciences et Techniques de la Mer, Conservatoire National des Arts et Métiers, 50103 Cherbourg en Cotentin Cedex, France; Laboratoire Universitaire des Sciences Appliquées de Cherbourg, EA4253, Normandie Université, UNICAEN, 50130 Cherbourg en Cotentin, France.
| | - Marie Pallud
- Institut National des Sciences et Techniques de la Mer, Conservatoire National des Arts et Métiers, 50103 Cherbourg en Cotentin Cedex, France; IFREMER, LEAD NC, Equipe Ecophysiologie Station aquacole de Saint Vincent, Boulouparis, 98897 Nouvelle Calédonie Cedex, France.
| | - Lauriane Kuhn
- Plateforme Protéomique Strasbourg Esplanade, CNRS FRC 1589, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg Cedex, France.
| | - Philippe Hammann
- Plateforme Protéomique Strasbourg Esplanade, CNRS FRC 1589, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg Cedex, France.
| | - Arnaud Demortière
- Laboratoire de Réactivité et Chimie des Solides, CNRS UMR 7314, Université de Picardie Jules Verne, 80039 Amiens Cedex 1, France; Réseau sur le Stockage Electrochimique de l'Energie (RS2E), CNRS FR 3459, 80039 Amiens Cedex 1, France; Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439, United States.
| | - Arash Jamali
- Laboratoire de Réactivité et Chimie des Solides, CNRS UMR 7314, Université de Picardie Jules Verne, 80039 Amiens Cedex 1, France.
| | - Johana Chicher
- Plateforme Protéomique Strasbourg Esplanade, CNRS FRC 1589, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg Cedex, France.
| | - Christelle Caplat
- UMR BOREA, UCBN, MNHN, UPMC, CNRS-7208, IRD-207, Institut de Biologie Fondamentale et Appliquée, Normandie Université, UNICAEN, 14032 Caen Cedex 5, France.
| | - Régis Kevin Gallon
- Institut National des Sciences et Techniques de la Mer, Conservatoire National des Arts et Métiers, 50103 Cherbourg en Cotentin Cedex, France; Laboratoire Universitaire des Sciences Appliquées de Cherbourg, EA4253, Normandie Université, UNICAEN, 50130 Cherbourg en Cotentin, France.
| | - Martine Bertrand
- Institut National des Sciences et Techniques de la Mer, Conservatoire National des Arts et Métiers, 50103 Cherbourg en Cotentin Cedex, France; Laboratoire Universitaire des Sciences Appliquées de Cherbourg, EA4253, Normandie Université, UNICAEN, 50130 Cherbourg en Cotentin, France.
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96
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Yu X, Cai G, Wang H, Hu Z, Zheng W, Lei X, Zhu X, Chen Y, Chen Q, Din H, Xu H, Tian Y, Fu L, Zheng T. Fast-growing algicidal Streptomyces sp. U3 and its potential in harmful algal bloom controls. JOURNAL OF HAZARDOUS MATERIALS 2018; 341:138-149. [PMID: 28777959 DOI: 10.1016/j.jhazmat.2017.06.046] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 06/18/2017] [Accepted: 06/20/2017] [Indexed: 06/07/2023]
Abstract
To find the potential algicidal microorganisms and apply them to prevent and terminate harmful algal blooms (HABs), we isolated an actinomycete U3 from Mangrove, which had a potent algicidal effect on the harmful alga Heterosigma akashiwo. It could completely lyse the algal cells by producing active compounds, which were highly sensitive to high temperature and strong alkaline, but resistant to acid. One μg/mL of crude extract of the fermentation supernatant could kill 70% of H. akashiwo cells in 3 d. Unlike most of the other known algicidal Streptomyces, U3 showed strong ability of proliferation with the algal inclusion as the nutrient source. The washed mycelial pellets also gradually exhibited significant algicidal effect during the visible growth in the algal culture. It suggests that U3 could efficiently absorb nutrients from algal culture to support its growth and produce algicidal compounds that might cause the autophagy of algal cells. Therefore, applying U3, as a long-term and environmentally friendly bio-agent to control the harmful blooms of H. akashiwo, would be effective and promising. And the decrease of bioavailable DOM and increase of bio-refractory DOM during the algicidal process of U3 provided new insights into the ecological influence of algicial microorganisms on marine ecosystem.
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Affiliation(s)
- Xiaoqi Yu
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Guanjing Cai
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Hui Wang
- Biology Department, College of Life Science, Shantou University, Shantou 515063, China
| | - Zhong Hu
- Biology Department, College of Life Science, Shantou University, Shantou 515063, China
| | - Wei Zheng
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Xueqian Lei
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Xiaoying Zhu
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Yao Chen
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Qiuliang Chen
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Hongyan Din
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Hong Xu
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Yun Tian
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Lijun Fu
- Fujian Provincial Key Laboratory of Ecology-Toxicological Effects & Control for Emerging Contaminants, Putian University, Putian 351100, China.
| | - Tianling Zheng
- State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China.
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97
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Klemenčič M, Funk C. Structural and functional diversity of caspase homologues in non-metazoan organisms. PROTOPLASMA 2018; 255:387-397. [PMID: 28744694 PMCID: PMC5756287 DOI: 10.1007/s00709-017-1145-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/05/2017] [Indexed: 05/03/2023]
Abstract
Caspases, the proteases involved in initiation and execution of metazoan programmed cell death, are only present in animals, while their structural homologues can be found in all domains of life, spanning from simple prokaryotes (orthocaspases) to yeast and plants (metacaspases). All members of this wide protease family contain the p20 domain, which harbours the catalytic dyad formed by the two amino acid residues, histidine and cysteine. Despite the high structural similarity of the p20 domain, metacaspases and orthocaspases were found to exhibit different substrate specificities than caspases. While the former cleave their substrates after basic amino acid residues, the latter accommodate substrates with negative charge. This observation is crucial for the re-evaluation of non-metazoan caspase homologues being involved in processes of programmed cell death. In this review, we analyse the structural diversity of enzymes containing the p20 domain, with focus on the orthocaspases, and summarise recent advances in research of orthocaspases and metacaspases of cyanobacteria, algae and higher plants. Although caspase homologues were initially proposed to be involved in execution of cell death, accumulating evidence supports the role of metacaspases and orthocaspases as important contributors to cell homeostasis during normal physiological conditions or cell differentiation and ageing.
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Affiliation(s)
- Marina Klemenčič
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden.
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000, Ljubljana, Slovenia.
| | - Christiane Funk
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
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98
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Liu J, Cai W, Fang X, Wang X, Li G. Virus-induced apoptosis and phosphorylation form of metacaspase in the marine coccolithophorid Emiliania huxleyi. Arch Microbiol 2017; 200:413-422. [DOI: 10.1007/s00203-017-1460-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 09/01/2017] [Accepted: 11/17/2017] [Indexed: 12/12/2022]
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99
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Autoinhibitory sterol sulfates mediate programmed cell death in a bloom-forming marine diatom. Nat Commun 2017; 8:1292. [PMID: 29101388 PMCID: PMC5670183 DOI: 10.1038/s41467-017-01300-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 09/07/2017] [Indexed: 01/07/2023] Open
Abstract
Cell mortality is a key mechanism that shapes phytoplankton blooms and species dynamics in aquatic environments. Here we show that sterol sulfates (StS) are regulatory molecules of a cell death program in Skeletonema marinoi, a marine diatom-blooming species in temperate coastal waters. The molecules trigger an oxidative burst and production of nitric oxide in a dose-dependent manner. The intracellular level of StS increases with cell ageing and ultimately leads to a mechanism of apoptosis-like death. Disrupting StS biosynthesis by inhibition of the sulfonation step significantly delays the onset of this fatal process and maintains steady growth in algal cells for several days. The autoinhibitory activity of StS demonstrates the functional significance of small metabolites in diatoms. The StS pathway provides another view on cell regulation during bloom dynamics in marine habitats and opens new opportunities for the biochemical control of mass-cultivation of microalgae. Phytoplankton blooms are shaped by a period of rapid growth followed by massive cell death. Here the authors show that sterol sulfates accumulate in aging cells of a bloom-forming marine diatom and trigger an oxidative burst that leads to a mechanism of apoptosis-like death.
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100
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Koonin EV, Krupovic M. Polintons, virophages and transpovirons: a tangled web linking viruses, transposons and immunity. Curr Opin Virol 2017; 25:7-15. [PMID: 28672161 DOI: 10.1016/j.coviro.2017.06.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/30/2017] [Accepted: 06/19/2017] [Indexed: 11/15/2022]
Abstract
Virophages are satellite DNA viruses that depend for their replication on giant viruses of the family Mimiviridae. An evolutionary relationship exists between the virophages and Polintons, large self-synthesizing transposons that are wide spread in the genomes of diverse eukaryotes. Most of the Polintons encode homologs of major and minor icosahedral virus capsid proteins and accordingly are predicted to form virions. Additionally, metagenome analysis has led to the discovery of an expansive family of Polinton-like viruses (PLV) that are more distantly related to bona fide Polintons and virophages. Another group of giant virus parasites includes small, linear, double-stranded DNA elements called transpovirons. Recent in-depth comparative genomic analysis has yielded evidence of the origin of the PLV and the transpovirons from Polintons. Integration of virophage genomes into genomes of both giant viruses and protists has been demonstrated. Furthermore, in an experimental coinfection system that consisted of a protist host, a giant virus and an associated virophage, the virophage integrated into the host genome and, after activation of its expression by a superinfecting giant virus, served as an agent of adaptive immunity. There is a striking analogy between this mechanism and the CRISPR-Cas system of prokaryotic adaptive immunity. Taken together, these findings show that Polintons, PLV, virophages and transpovirons form a dynamic network of integrating mobile genetic elements that contribute to the cellular antivirus defense and host-virus coevolution.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
| | - Mart Krupovic
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Department of Microbiology, Institut Pasteur, Paris, France.
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