Pub Date : 2022-07-21DOI: 10.1080/09670262.2022.2092215
Jeffrey D. Leblond, Lindsey C. Elkins, Jori E. Graeff, Kyra Sabir
ABSTRACT The genus Amphidinium is shown in many phylogenies to be basal to other peridinin-containing, photosynthetic dinoflagellates as one of the first photosynthetic genera to arise after the evolution of heterotrophic genera. As part of our continuing examination of the plastid-associated galactolipids, namely mono- and digalactosyldiacylglycerol (MGDG and DGDG, respectively), in dinoflagellates, we here examine the galactolipid composition of members of the genus Amphidinium. We show that this genus is characterized by an abundance of 20:5(n-3)/18:5(n-3) and 20:5(n-3)/18:4(n-3) forms of MGDG and DGDG (with sn-1/sn-2 regiochemical specificity of fatty acids), but also sometimes with generally lesser amounts of some polyunsaturated C18/C18 forms, thus placing the examined species within a previously identified cluster of C20/C18 MGDG- and DGDG-containing, peridinin-containing dinoflagellates. We also show that Testudodinium testudo, previously known as Amphidinium testudo, conversely falls within a previously identified C18/C18 cluster, indicating a distinct difference in galactolipid biosynthesis capability. While it is likely that further revision of the genus may occur in the future and/or more basal peridinin-containing, photosynthetic genera may be discovered, at the current time Amphidinium is the currently agreed-upon most basal dinoflagellate genus for which isolates are available for biochemical characterization such as what we describe in this paper. Thus, because of the presumed basal position of the genus Amphidinium, we present a hypothesis that its galactolipids currently represent those that are ancestral to other genera of peridinin-containing dinoflagellates, including those within the C18/C18 cluster. Highlights Amphidinium species’ galactolipids reside within the C20/C18 peridinin dinoflagellate cluster. Conversely, Testudodinium testudo (formerly Amphidinium testudo) falls within the C18/C18 cluster. We hypothesize Amphidinium’s galactolipids as basal to other peridinin dinoflagellates.
{"title":"Galactolipids of the genus Amphidinium (Dinophyceae): an hypothesis that they are basal to those of other peridinin-containing dinoflagellates","authors":"Jeffrey D. Leblond, Lindsey C. Elkins, Jori E. Graeff, Kyra Sabir","doi":"10.1080/09670262.2022.2092215","DOIUrl":"https://doi.org/10.1080/09670262.2022.2092215","url":null,"abstract":"ABSTRACT The genus Amphidinium is shown in many phylogenies to be basal to other peridinin-containing, photosynthetic dinoflagellates as one of the first photosynthetic genera to arise after the evolution of heterotrophic genera. As part of our continuing examination of the plastid-associated galactolipids, namely mono- and digalactosyldiacylglycerol (MGDG and DGDG, respectively), in dinoflagellates, we here examine the galactolipid composition of members of the genus Amphidinium. We show that this genus is characterized by an abundance of 20:5(n-3)/18:5(n-3) and 20:5(n-3)/18:4(n-3) forms of MGDG and DGDG (with sn-1/sn-2 regiochemical specificity of fatty acids), but also sometimes with generally lesser amounts of some polyunsaturated C18/C18 forms, thus placing the examined species within a previously identified cluster of C20/C18 MGDG- and DGDG-containing, peridinin-containing dinoflagellates. We also show that Testudodinium testudo, previously known as Amphidinium testudo, conversely falls within a previously identified C18/C18 cluster, indicating a distinct difference in galactolipid biosynthesis capability. While it is likely that further revision of the genus may occur in the future and/or more basal peridinin-containing, photosynthetic genera may be discovered, at the current time Amphidinium is the currently agreed-upon most basal dinoflagellate genus for which isolates are available for biochemical characterization such as what we describe in this paper. Thus, because of the presumed basal position of the genus Amphidinium, we present a hypothesis that its galactolipids currently represent those that are ancestral to other genera of peridinin-containing dinoflagellates, including those within the C18/C18 cluster. Highlights Amphidinium species’ galactolipids reside within the C20/C18 peridinin dinoflagellate cluster. Conversely, Testudodinium testudo (formerly Amphidinium testudo) falls within the C18/C18 cluster. We hypothesize Amphidinium’s galactolipids as basal to other peridinin dinoflagellates.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"190 - 198"},"PeriodicalIF":2.4,"publicationDate":"2022-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45695404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-20DOI: 10.1080/09670262.2022.2089913
P. Pribyl, Lenka Procházková
ABSTRACT A new freshwater microalgal isolate, CCALA 1135, was characterized using a polyphasic approach (morphology, ultrastructure, fatty acid composition, 18S rRNA gene and rbcL analyses). Non-motile vegetative cells were spherical with thick, smooth cell walls lacking ornamentation, with multiple overlapping chloroplasts and sometimes more than one red globule in the cytoplasm. The nuclear and chloroplast envelopes formed a continuous membrane and there was no pyrenoid. These morphological and ultrastructural features indicated assignment to the class Eustigmatophyceae. The strain was, however, unique in its mode of reproduction: only zoospores were formed, but no autospores were observed (i.e. obligate zoospory, which is rare in the Eustigmatophyceae). The zoospores were relatively fragile and their morphology was similar to those of other members of the clade Goniochloridales (a clade name under the PhyloCode) that have been studied, being uniflagellate and lacking an eyespot. A very high proportion of polyunsaturated fatty acids (up to 57% of total fatty acids) was found, dominated by nutritionally valuable arachidonic and eicosapentaenoic acids, the latter being the most abundant FA (up to 35%) in the total profile. Phylogenetic analysis based on 18S rDNA and rbcL sequences confirmed that CCALA 1135 represents a new member of Goniochloridales clade IIc. Based on cellular morphology, ultrastructure and molecular data we propose this strain as a new species and new genus of the Eustigmatophyceae, Trebonskia zoosporica gen. et sp. nov. Our work is a step toward clarifying the taxonomy of a group of the Eustigmatophyceae with many unnamed strains awaiting characterization. Highlights A new genus and species of Eustigmatophyceae is described using a polyphasic approach. This isolate reproduces only by zoospores, a mode rare within Eustigmatophyceae. It contained a high proportion of nutritionally valuable polyunsaturated fatty acids.
摘要采用多相方法(形态学、超微结构、脂肪酸组成、18S rRNA基因和rbcL分析)对一种新的淡水微藻CCALA 1135进行了表征。不运动的营养细胞呈球形，细胞壁厚而光滑，没有纹饰，有多个重叠的叶绿体，有时细胞质中有一个以上的红色球体。核膜与叶绿体膜呈连续膜，无类pyrenox。这些形态和超微结构特征表明该植物属于真穗草纲。然而，该菌株的繁殖方式是独特的:只形成游动孢子，但没有观察到自孢子(即专性游动孢子，这在真真菌中很少见)。游动孢子相对脆弱，它们的形态与已经研究过的Goniochloridales分支的其他成员相似，都是单毛的，没有眼点。发现了非常高比例的多不饱和脂肪酸(高达总脂肪酸的57%)，主要是营养价值高的花生四烯酸和二十碳五烯酸，后者是总谱中最丰富的FA(高达35%)。基于18S rDNA和rbcL序列的系统发育分析证实，CCALA 1135是Goniochloridales IIc分支的一个新成员。基于细胞形态学、超微结构和分子数据，我们提出了该菌株作为真菌科(Eustigmatophyceae, Trebonskia zoosporica gen. et sp. 11)的新种和新属。我们的工作是澄清真菌科(Eustigmatophyceae)的一组分类的一步，还有许多未命名的菌株有待鉴定。利用多相方法描述了一种新属和新种。该分离株仅通过游动孢子繁殖，这种模式在真真菌科中很少见。它含有高比例的营养价值的多不饱和脂肪酸。
{"title":"Trebonskia zoosporica, gen. et sp. nov., a new member of the Goniochloridales (Eustigmatophyceae, Stramenopiles) with an unusual mode of reproduction","authors":"P. Pribyl, Lenka Procházková","doi":"10.1080/09670262.2022.2089913","DOIUrl":"https://doi.org/10.1080/09670262.2022.2089913","url":null,"abstract":"ABSTRACT A new freshwater microalgal isolate, CCALA 1135, was characterized using a polyphasic approach (morphology, ultrastructure, fatty acid composition, 18S rRNA gene and rbcL analyses). Non-motile vegetative cells were spherical with thick, smooth cell walls lacking ornamentation, with multiple overlapping chloroplasts and sometimes more than one red globule in the cytoplasm. The nuclear and chloroplast envelopes formed a continuous membrane and there was no pyrenoid. These morphological and ultrastructural features indicated assignment to the class Eustigmatophyceae. The strain was, however, unique in its mode of reproduction: only zoospores were formed, but no autospores were observed (i.e. obligate zoospory, which is rare in the Eustigmatophyceae). The zoospores were relatively fragile and their morphology was similar to those of other members of the clade Goniochloridales (a clade name under the PhyloCode) that have been studied, being uniflagellate and lacking an eyespot. A very high proportion of polyunsaturated fatty acids (up to 57% of total fatty acids) was found, dominated by nutritionally valuable arachidonic and eicosapentaenoic acids, the latter being the most abundant FA (up to 35%) in the total profile. Phylogenetic analysis based on 18S rDNA and rbcL sequences confirmed that CCALA 1135 represents a new member of Goniochloridales clade IIc. Based on cellular morphology, ultrastructure and molecular data we propose this strain as a new species and new genus of the Eustigmatophyceae, Trebonskia zoosporica gen. et sp. nov. Our work is a step toward clarifying the taxonomy of a group of the Eustigmatophyceae with many unnamed strains awaiting characterization. Highlights A new genus and species of Eustigmatophyceae is described using a polyphasic approach. This isolate reproduces only by zoospores, a mode rare within Eustigmatophyceae. It contained a high proportion of nutritionally valuable polyunsaturated fatty acids.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"199 - 213"},"PeriodicalIF":2.4,"publicationDate":"2022-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48559978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-20DOI: 10.1080/09670262.2022.2081731
R. Sánchez de Pedro, Andrea N. Fernández, M. García-Sánchez, A. Flores‐Moya, E. Bañares‐España
Abstract Thermotolerance acquisition is an important ecophysiological trait under global warming scenarios because it can allow organisms and populations to adapt, particularly during the most sensitive early stages of a life cycle. Here we used seasonality as a natural scenario to explore whether parental thermal histories can modulate thermotolerance of recruits of a canopy-forming intertidal seaweed (Fucus guiryi) across an ecologically relevant thermal gradient (15–28°C). For this purpose, we harvested embryos from parents after the periods of maximum and minimum accumulated heat exposure (late summer and late winter), and at the onset of summer. During early ontogeny we followed initial embryo size, internal nutrient content, survival, growth and developmental stages as performance metrics to address whether parental acclimation modulates thermal tolerance via provisioning or parental effects. Late winter recruits of F. guiryi exhibited the greatest thermotolerance, showing a broader range of optimal temperatures and higher upper thermal limits for growth and survival, probably associated with better provisioning from parental thalli. Physiological fitness of recruits decreased above 25°C, showing arrested growth, impaired development and dropping survival rates, but functional loss was more abrupt in early summer. Late summer responses confirmed that heat hardening occurs in natural populations, but at the seasonal scale the adaptive significance of this increased thermotolerance is much lower than that induced by winter parental provisioning. Heat-induced thermotolerance occurred from early to late summer due to parental exposure to warming. However, winter provisioning promoted greater thermotolerance acquisition. Exposure to moderate thermal stress at the onset of summer without prior seasonal acclimation resulted in minimum levels of thermal tolerance and loss of offspring fitness. While warmer winters might be neutral or benefit early development, increasing temperatures and poor nutritional conditions at the onset of the summer season may reduce survival and hamper population recruitment. Highlights Thermotolerance of Fucus guiryi increased towards the late cold season. Early summer recruits had the lowest survival under warming. Seasonal performance of recruits might be driven by parental environment.
{"title":"Parental environment modulates offspring thermal tolerance in a foundational intertidal seaweed","authors":"R. Sánchez de Pedro, Andrea N. Fernández, M. García-Sánchez, A. Flores‐Moya, E. Bañares‐España","doi":"10.1080/09670262.2022.2081731","DOIUrl":"https://doi.org/10.1080/09670262.2022.2081731","url":null,"abstract":"Abstract Thermotolerance acquisition is an important ecophysiological trait under global warming scenarios because it can allow organisms and populations to adapt, particularly during the most sensitive early stages of a life cycle. Here we used seasonality as a natural scenario to explore whether parental thermal histories can modulate thermotolerance of recruits of a canopy-forming intertidal seaweed (Fucus guiryi) across an ecologically relevant thermal gradient (15–28°C). For this purpose, we harvested embryos from parents after the periods of maximum and minimum accumulated heat exposure (late summer and late winter), and at the onset of summer. During early ontogeny we followed initial embryo size, internal nutrient content, survival, growth and developmental stages as performance metrics to address whether parental acclimation modulates thermal tolerance via provisioning or parental effects. Late winter recruits of F. guiryi exhibited the greatest thermotolerance, showing a broader range of optimal temperatures and higher upper thermal limits for growth and survival, probably associated with better provisioning from parental thalli. Physiological fitness of recruits decreased above 25°C, showing arrested growth, impaired development and dropping survival rates, but functional loss was more abrupt in early summer. Late summer responses confirmed that heat hardening occurs in natural populations, but at the seasonal scale the adaptive significance of this increased thermotolerance is much lower than that induced by winter parental provisioning. Heat-induced thermotolerance occurred from early to late summer due to parental exposure to warming. However, winter provisioning promoted greater thermotolerance acquisition. Exposure to moderate thermal stress at the onset of summer without prior seasonal acclimation resulted in minimum levels of thermal tolerance and loss of offspring fitness. While warmer winters might be neutral or benefit early development, increasing temperatures and poor nutritional conditions at the onset of the summer season may reduce survival and hamper population recruitment. Highlights Thermotolerance of Fucus guiryi increased towards the late cold season. Early summer recruits had the lowest survival under warming. Seasonal performance of recruits might be driven by parental environment.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"121 - 144"},"PeriodicalIF":2.4,"publicationDate":"2022-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45460987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-18DOI: 10.1080/09670262.2022.2086710
Lia P. Godinho, Lucía Soliño, Catarina Churro, V. Timóteo, Carolina Santos, Neide Gouveia, J. Diogène, Pedro Reis Costa
ABSTRACT The emerging threat of ciguatera poisoning (CP) in Europe has been associated with fish captured in the Canary Islands (Spain) and Selvagens Islands (Portugal). The first are heavily populated islands where numerous scientific studies have been carried out. Conversely, the Selvagens Islands as a nature reserve with low human pressure have been rarely surveyed in terms of the marine benthic microalgae, including the epiphytic ciguatera-causing dinoflagellate species. To investigate the harmful microalgal diversity of the Selvagens Islands, a scientific cruise to these remote islands took place in September, 2018. The Gambierdiscus species composition and distribution, and the associated epiphytic dinoflagellate community, were assessed using artificial substrate devices. Gambierdiscus cells were found in all samples, reaching concentrations of up to 725 cells 100 cm–2. G. australes was the only species identified after morphological and molecular analysis of the retrieved cultures. Species identification was confirmed by molecular characterization based on the LSU D8–D10 region. Nevertheless, phylogenetic studies indicated that some strains diverged from the G. australes clade suggesting genetic differentiation. Toxicity was estimated by neuro-2a cell-based assay in four strains, ranging from 2.46–83 fg of CTX1B eq. cell–1. The epiphytic dinoflagellate community that co-occurred with Gambierdiscus comprised other toxic or potentially toxic dinoflagellates, such as Ostreopsis, Prorocentrum, Amphidinium and Coolia species. Oceanographic and meteorological data were also obtained to characterize the occurrence of Gambierdiscus. This study is the first stage in understanding the role of the Selvagens Islands in the incubation and proliferation of the ciguatera-causing dinoflagellates Gambierdiscus in the NE Atlantic. Highlights The Selvagens Islands are a ciguatera hotspot in Europe. Gambierdiscus australes was the only species observed in the Selvagens Islands. Strains diverging from the G. australes clade suggest genetic differentiation.
{"title":"Distribution, identification and cytotoxicity of Gambierdiscus (Dinophyceae) in the Atlantic Selvagens Islands (Madeira, Portugal): a ciguatera gateway to Europe","authors":"Lia P. Godinho, Lucía Soliño, Catarina Churro, V. Timóteo, Carolina Santos, Neide Gouveia, J. Diogène, Pedro Reis Costa","doi":"10.1080/09670262.2022.2086710","DOIUrl":"https://doi.org/10.1080/09670262.2022.2086710","url":null,"abstract":"ABSTRACT The emerging threat of ciguatera poisoning (CP) in Europe has been associated with fish captured in the Canary Islands (Spain) and Selvagens Islands (Portugal). The first are heavily populated islands where numerous scientific studies have been carried out. Conversely, the Selvagens Islands as a nature reserve with low human pressure have been rarely surveyed in terms of the marine benthic microalgae, including the epiphytic ciguatera-causing dinoflagellate species. To investigate the harmful microalgal diversity of the Selvagens Islands, a scientific cruise to these remote islands took place in September, 2018. The Gambierdiscus species composition and distribution, and the associated epiphytic dinoflagellate community, were assessed using artificial substrate devices. Gambierdiscus cells were found in all samples, reaching concentrations of up to 725 cells 100 cm–2. G. australes was the only species identified after morphological and molecular analysis of the retrieved cultures. Species identification was confirmed by molecular characterization based on the LSU D8–D10 region. Nevertheless, phylogenetic studies indicated that some strains diverged from the G. australes clade suggesting genetic differentiation. Toxicity was estimated by neuro-2a cell-based assay in four strains, ranging from 2.46–83 fg of CTX1B eq. cell–1. The epiphytic dinoflagellate community that co-occurred with Gambierdiscus comprised other toxic or potentially toxic dinoflagellates, such as Ostreopsis, Prorocentrum, Amphidinium and Coolia species. Oceanographic and meteorological data were also obtained to characterize the occurrence of Gambierdiscus. This study is the first stage in understanding the role of the Selvagens Islands in the incubation and proliferation of the ciguatera-causing dinoflagellates Gambierdiscus in the NE Atlantic. Highlights The Selvagens Islands are a ciguatera hotspot in Europe. Gambierdiscus australes was the only species observed in the Selvagens Islands. Strains diverging from the G. australes clade suggest genetic differentiation.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"156 - 168"},"PeriodicalIF":2.4,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45292908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-13DOI: 10.1080/09670262.2022.2076291
E. Greipel, J. Kutasi, K. Solymosi, H. Nagy, T. Felföldi
ABSTRACT Chlorococcum is a coccoid green algal genus, which contains almost 50 species. The genus is polyphyletic, but in a traditional sense, the cells are coccoid and non-motile with a cup-shape chloroplast in the vegetative stage, while the spores have chlamydomonad appearance. They are distributed worldwide mainly in terrestrial habitats, and the biotechnological potential of several strains has been reported. In this study, three new green algal strains from a shallow, temporary freshwater lake in Hungary are characterized using microscopic (light and transmission electron microscopy) and DNA-based methods (phylogenetic analysis of the ribosomal ITS region, the 18S ribosomal RNA and rbcL genes, and ITS secondary structure comparison). Based on the obtained results, one of the three new isolates is considered to represent a new species, which is described here as Chlorococcum szentendrense sp. nov.
{"title":"Hidden diversity of Chlorococcum (Chlorophyta) in a shallow temporary freshwater lake: description of Chlorococcum szentendrense sp. nov","authors":"E. Greipel, J. Kutasi, K. Solymosi, H. Nagy, T. Felföldi","doi":"10.1080/09670262.2022.2076291","DOIUrl":"https://doi.org/10.1080/09670262.2022.2076291","url":null,"abstract":"ABSTRACT Chlorococcum is a coccoid green algal genus, which contains almost 50 species. The genus is polyphyletic, but in a traditional sense, the cells are coccoid and non-motile with a cup-shape chloroplast in the vegetative stage, while the spores have chlamydomonad appearance. They are distributed worldwide mainly in terrestrial habitats, and the biotechnological potential of several strains has been reported. In this study, three new green algal strains from a shallow, temporary freshwater lake in Hungary are characterized using microscopic (light and transmission electron microscopy) and DNA-based methods (phylogenetic analysis of the ribosomal ITS region, the 18S ribosomal RNA and rbcL genes, and ITS secondary structure comparison). Based on the obtained results, one of the three new isolates is considered to represent a new species, which is described here as Chlorococcum szentendrense sp. nov.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"110 - 120"},"PeriodicalIF":2.4,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44284692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-25DOI: 10.1080/09670262.2022.2065365
S. Barrientos, R. Barreiro, Cristina Piñeiro‐Corbeira
ABSTRACT Kelp forests, one of the world’s most productive ecosystems, have been in decline in many regions in recent years. Climate change, through steady sea warming or marine heatwaves, has led to the disappearance of entire populations, although kelp forest decline may also depend on non-climatic stressors such as grazing. Since the impacts of climate change are projected to continue to intensify for decades, marine protected areas (MPAs) have been suggested as a cost-effective strategy to boost the resilience of marine ecosystems. However, implementing an MPA does not guarantee that all components of the local community will benefit from it. In NW Spain, several stakeholders reported the decline of Laminaria ochroleuca inside the Islas Atlánticas Marine National Park in recent years, but the extent and possible drivers of this decline have not been investigated. Using a combination of quadrat-scale (abundance, biomass) and transect-scale (cover) seasonal surveys over one year, we found striking differences between L. ochroleuca reefs inside and outside the MPA. Populations outside the MPA were the typical canopy forests expected for a perennial kelp, stable year-round and composed mostly of adults. Inside the MPA, however, grazing prevented the canopy phase from being reached. Instead, only mid-sized young plants were detected in autumn, but most had disappeared by winter, and those that remained had been degraded by herbivores to mere blade-less stipes with no growth meristem that eventually perish. Further research seems warranted to monitor whether this phenomenon spreads to nearby kelp beds outside the MPA. Meanwhile, restoring MPA kelp reefs will more likely require efforts to reduce herbivore activity (e.g. translocations, exclusion devices) than to bolster kelp populations. HIGHLIGHTS • Kelp canopies recurrently failed inside a MPA in recent years.• Neither propagule supply nor environmental conditions explain the failure.• Grazers keep a canopy-free state by eradicating recently recruited kelps.
{"title":"Paradoxical failure of Laminaria ochroleuca (Laminariales, Phaeophyceae) to consolidate a kelp forest inside a Marine National Park","authors":"S. Barrientos, R. Barreiro, Cristina Piñeiro‐Corbeira","doi":"10.1080/09670262.2022.2065365","DOIUrl":"https://doi.org/10.1080/09670262.2022.2065365","url":null,"abstract":"ABSTRACT Kelp forests, one of the world’s most productive ecosystems, have been in decline in many regions in recent years. Climate change, through steady sea warming or marine heatwaves, has led to the disappearance of entire populations, although kelp forest decline may also depend on non-climatic stressors such as grazing. Since the impacts of climate change are projected to continue to intensify for decades, marine protected areas (MPAs) have been suggested as a cost-effective strategy to boost the resilience of marine ecosystems. However, implementing an MPA does not guarantee that all components of the local community will benefit from it. In NW Spain, several stakeholders reported the decline of Laminaria ochroleuca inside the Islas Atlánticas Marine National Park in recent years, but the extent and possible drivers of this decline have not been investigated. Using a combination of quadrat-scale (abundance, biomass) and transect-scale (cover) seasonal surveys over one year, we found striking differences between L. ochroleuca reefs inside and outside the MPA. Populations outside the MPA were the typical canopy forests expected for a perennial kelp, stable year-round and composed mostly of adults. Inside the MPA, however, grazing prevented the canopy phase from being reached. Instead, only mid-sized young plants were detected in autumn, but most had disappeared by winter, and those that remained had been degraded by herbivores to mere blade-less stipes with no growth meristem that eventually perish. Further research seems warranted to monitor whether this phenomenon spreads to nearby kelp beds outside the MPA. Meanwhile, restoring MPA kelp reefs will more likely require efforts to reduce herbivore activity (e.g. translocations, exclusion devices) than to bolster kelp populations. HIGHLIGHTS • Kelp canopies recurrently failed inside a MPA in recent years.• Neither propagule supply nor environmental conditions explain the failure.• Grazers keep a canopy-free state by eradicating recently recruited kelps.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"72 - 82"},"PeriodicalIF":2.4,"publicationDate":"2022-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42535389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-20DOI: 10.1080/09670262.2022.2066188
Regina Kolzenburg, D. Coaten, F. Ragazzola
Abstract Intertidal macroalgae are exposed to many biotic and abiotic stressors, including significant fluctuations in environmental parameters such as salinity, temperature, pH and solar radiation. This study characterized populations of the intertidal calcifying red alga Corallina officinalis across its geographic distribution in the North-east Atlantic. Processes examined included primary production, respiration, light and dark calcification, photosynthesis-irradiance, and calcification-irradiance evolution. Results confirmed significant differences in the physiology of C. officinalis between latitudes with a clear north-to-south gradient. Compared with central and southern populations of this species, northern populations appeared to be the most robust, showing potential for local physiological adaptation in response to increased variability in environmental factors present within their habitat. Conversely, southern populations displayed a distinct lack of local adaptation compared with northern populations. This is possibly due to southern populations being located within an environment at the upper limit of their stress tolerance, therefore restricting the species’ ability to adapt. As a result, future permanent decline, or even disappearance, of C. officinalis within southern locations of the North-east Atlantic could occur, a process that is likely to be accelerated by predicted future climatic changes. Furthermore, given the essential role these ecosystem engineers play within their habitat, any loss of C. officinalis is also expected to have a strongly negative impact on the surrounding environment. HIGHLIGHTS Decoupled photosynthesis and calcification in Corallina. officinalis show complex relationships, not direct dependencies. Most physiological characteristics in northern C. officinalis populations differ significantly from those in central and southern locations. Species adaptation is predominantly to lower light and temperature conditions.
{"title":"Physiological characterisation of the calcified alga Corallina officinalis (Rhodophyta) from the leading to trailing edge in the Northeast Atlantic","authors":"Regina Kolzenburg, D. Coaten, F. Ragazzola","doi":"10.1080/09670262.2022.2066188","DOIUrl":"https://doi.org/10.1080/09670262.2022.2066188","url":null,"abstract":"Abstract Intertidal macroalgae are exposed to many biotic and abiotic stressors, including significant fluctuations in environmental parameters such as salinity, temperature, pH and solar radiation. This study characterized populations of the intertidal calcifying red alga Corallina officinalis across its geographic distribution in the North-east Atlantic. Processes examined included primary production, respiration, light and dark calcification, photosynthesis-irradiance, and calcification-irradiance evolution. Results confirmed significant differences in the physiology of C. officinalis between latitudes with a clear north-to-south gradient. Compared with central and southern populations of this species, northern populations appeared to be the most robust, showing potential for local physiological adaptation in response to increased variability in environmental factors present within their habitat. Conversely, southern populations displayed a distinct lack of local adaptation compared with northern populations. This is possibly due to southern populations being located within an environment at the upper limit of their stress tolerance, therefore restricting the species’ ability to adapt. As a result, future permanent decline, or even disappearance, of C. officinalis within southern locations of the North-east Atlantic could occur, a process that is likely to be accelerated by predicted future climatic changes. Furthermore, given the essential role these ecosystem engineers play within their habitat, any loss of C. officinalis is also expected to have a strongly negative impact on the surrounding environment. HIGHLIGHTS Decoupled photosynthesis and calcification in Corallina. officinalis show complex relationships, not direct dependencies. Most physiological characteristics in northern C. officinalis populations differ significantly from those in central and southern locations. Species adaptation is predominantly to lower light and temperature conditions.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"83 - 98"},"PeriodicalIF":2.4,"publicationDate":"2022-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42518408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-13DOI: 10.1080/09670262.2022.2048268
Mary Joy Halog Libatique, Han-Yang Yeh, F. Nan, Meng-Chou Lee
ABSTRACT Algal susceptivity to inorganic arsenate As(V) is linked to the plant nutrient phosphate due to their similar uptake processes. This study determines the response of Sarcodia suae to three phosphate concentrations (1, 10 and 20 mg l–1) when exposed to As(V) (0, 250 µg l–1) for 7 days. The parameters measured include growth, pigments (Chlorophyll a (Chl a), allophycocyanin (APC), phycocyanin (PC), phycoerythrin (PE), total phycobiliproteins (TPBP) and carotenoids), inorganic arsenic (iAs), and total arsenic (TAs) uptake behaviour and bioaccumulation capacity. The growth rate showed significant differences among treatments. Significantly higher levels of pigments including Chl a and carotenoids were observed with an increase in external phosphate concentrations. On the other hand, APC, PC, PE and TPBP showed no significant differences among treatments. The trend of iAs and TAs uptake when phosphate is high suggests competition between phosphate and As(V) as is evident from the reduction of uptake with increased phosphate. The depletion of phosphate and As(V) in the medium also suggests accumulation by the algae. In addition, S. suae was considered an As accumulator but not a hyperaccumulator as defined on its bioaccumulation capacity of 48 and 97 mg kg–1 of iAs and TAs, respectively. Overall, these findings suggest that environmental factors including levels of phosphate have a key role in developing effective As bioremediation in the environment. Highlights Phosphate in Sarcodia suae probably regulates arsenic uptake. Photosynthetic pigments can be linked to competitive mechanisms of As(V). The red alga Sarcodia suae is a candidate for As wastewater treatments by Bioconcentration Factor analysis.
{"title":"Phosphate affects susceptivity of Sarcodia suae to arsenate","authors":"Mary Joy Halog Libatique, Han-Yang Yeh, F. Nan, Meng-Chou Lee","doi":"10.1080/09670262.2022.2048268","DOIUrl":"https://doi.org/10.1080/09670262.2022.2048268","url":null,"abstract":"ABSTRACT Algal susceptivity to inorganic arsenate As(V) is linked to the plant nutrient phosphate due to their similar uptake processes. This study determines the response of Sarcodia suae to three phosphate concentrations (1, 10 and 20 mg l–1) when exposed to As(V) (0, 250 µg l–1) for 7 days. The parameters measured include growth, pigments (Chlorophyll a (Chl a), allophycocyanin (APC), phycocyanin (PC), phycoerythrin (PE), total phycobiliproteins (TPBP) and carotenoids), inorganic arsenic (iAs), and total arsenic (TAs) uptake behaviour and bioaccumulation capacity. The growth rate showed significant differences among treatments. Significantly higher levels of pigments including Chl a and carotenoids were observed with an increase in external phosphate concentrations. On the other hand, APC, PC, PE and TPBP showed no significant differences among treatments. The trend of iAs and TAs uptake when phosphate is high suggests competition between phosphate and As(V) as is evident from the reduction of uptake with increased phosphate. The depletion of phosphate and As(V) in the medium also suggests accumulation by the algae. In addition, S. suae was considered an As accumulator but not a hyperaccumulator as defined on its bioaccumulation capacity of 48 and 97 mg kg–1 of iAs and TAs, respectively. Overall, these findings suggest that environmental factors including levels of phosphate have a key role in developing effective As bioremediation in the environment. Highlights Phosphate in Sarcodia suae probably regulates arsenic uptake. Photosynthetic pigments can be linked to competitive mechanisms of As(V). The red alga Sarcodia suae is a candidate for As wastewater treatments by Bioconcentration Factor analysis.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"45 - 57"},"PeriodicalIF":2.4,"publicationDate":"2022-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48772224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-04DOI: 10.1080/09670262.2022.2041731
M. M. Barreto Filho, I. L. Bagatini, Pierre M. Durand
Abstract Programmed cell death (PCD) plays a key role in unicellular microalgal ecology. However, the methodologies for detecting PCD are problematic. Clearly, to interpret the empirical data, clarity on how to measure microalgal PCD is essential. Here, we critically review the current measurements of PCD and provide suggestions for future methodological developments and interpretations. We review the traditional measures of PCD and associated cellular responses in microalgae and provide assessments of their frequencies of use and true positive rates. Traditional physiological measurements of photosynthetic activity, change in gene regulation, measurements of reactive oxygen species and terminal deoxynucleotidyl transferase dUTP nick end labelling are highly sensitive assays. They provide important measures of cellular physiological responses but are not unique to PCD. Both caspase-like and metacaspase activity reveal useful information about stress responses and demonstrate high (94% and 100%, respectively) positivity rates, however, they can play a role in cell activities other than death. Furthermore, the controversy surrounding positive caspase assays, even though microalgae encode metacaspases rather than orthologous caspases, is highlighted. DNA laddering had the lowest true positive rate (64%) and was not reported in diatoms while phosphatidylserine externalization was consistently positive in all taxa except dinoflagellates. These data illustrate the limitations of some PCD markers across different taxa. Ultrastructural alterations (transmission electron microscopy) were highly correlated with PCD across all microalgal taxa (true positive rate of 94%) and seem essential for the initial assessments of whether a cell is dying in an organized, ‘programmed’ way. However, in the face of the complexity of PCD phenotypes and the non-specific nature of the methodologies, no single indicator can be used to diagnose PCD. Here, we highlight the importance of employing a time-sensitive multi-assay approach to detect PCD in the eukaryotic microalgae before any ecological or evolutionary interpretations can be made. Highlights Measurements of PCD have different specificities and sensitivities. TEM appears essential as part of an initial investigation. Complementary markers provide information about cell stress and death responses.
{"title":"How shall we measure programmed cell death in eukaryotic microalgae?","authors":"M. M. Barreto Filho, I. L. Bagatini, Pierre M. Durand","doi":"10.1080/09670262.2022.2041731","DOIUrl":"https://doi.org/10.1080/09670262.2022.2041731","url":null,"abstract":"Abstract Programmed cell death (PCD) plays a key role in unicellular microalgal ecology. However, the methodologies for detecting PCD are problematic. Clearly, to interpret the empirical data, clarity on how to measure microalgal PCD is essential. Here, we critically review the current measurements of PCD and provide suggestions for future methodological developments and interpretations. We review the traditional measures of PCD and associated cellular responses in microalgae and provide assessments of their frequencies of use and true positive rates. Traditional physiological measurements of photosynthetic activity, change in gene regulation, measurements of reactive oxygen species and terminal deoxynucleotidyl transferase dUTP nick end labelling are highly sensitive assays. They provide important measures of cellular physiological responses but are not unique to PCD. Both caspase-like and metacaspase activity reveal useful information about stress responses and demonstrate high (94% and 100%, respectively) positivity rates, however, they can play a role in cell activities other than death. Furthermore, the controversy surrounding positive caspase assays, even though microalgae encode metacaspases rather than orthologous caspases, is highlighted. DNA laddering had the lowest true positive rate (64%) and was not reported in diatoms while phosphatidylserine externalization was consistently positive in all taxa except dinoflagellates. These data illustrate the limitations of some PCD markers across different taxa. Ultrastructural alterations (transmission electron microscopy) were highly correlated with PCD across all microalgal taxa (true positive rate of 94%) and seem essential for the initial assessments of whether a cell is dying in an organized, ‘programmed’ way. However, in the face of the complexity of PCD phenotypes and the non-specific nature of the methodologies, no single indicator can be used to diagnose PCD. Here, we highlight the importance of employing a time-sensitive multi-assay approach to detect PCD in the eukaryotic microalgae before any ecological or evolutionary interpretations can be made. Highlights Measurements of PCD have different specificities and sensitivities. TEM appears essential as part of an initial investigation. Complementary markers provide information about cell stress and death responses.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"13 - 34"},"PeriodicalIF":2.4,"publicationDate":"2022-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49093490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The order Oedogoniales comprises three genera, Oedogonium, Oedocladium and Bulbochaete, which were classified based on traditional morphological criteria, and includes more than 600 described species. This group is economically important in astaxanthin production and the energy sector. However, only one mitochondrial genome (mitogenome) has been reported so far. This study determined the mitochondrial genomes of seven Oedogoniales species, including six Oedogonium species and Oedocladium prescottii. Comparative analyses between the newly determined mitogenomes and the previously reported Bulbochaete rectangularis var. hiloensis mitogenome showed that all eight mitogenomes comprised 12 protein-coding genes (PCGs) and two rRNAs; however, the mitogenomes differed in their genome sizes, GC content, tRNAs, non-coding regions and introns. Synteny analysis of the eight mitogenomes revealed a high degree of syntenic conservation in general, with some rearrangements and inversions. The average nucleotide identity (ANI) analysis of the eight mitogenomes indicated Oedogonium dentireticulatum showed high similarity with Oedogonium sp3 (ANI of 96.32%). Most of the PCGs of the eight mitogenomes presented the conventional start codon ATG and stop codon TAR (TAA/TAG/TGA), and the synonymous codon preferences were conserved. Phylogenetic results indicated that Oedogonium was polyphyletic, and species of Oedocladium clustered with Oedogonium, while the position of B. rectangularis var. hiloensis was uncertain for the incongruent phylogenetic results. Statistical analyses of substitution rates demonstrated no significant differences among the three genera, and the dN/dS ratios based on branch model showed that cob, cox1 and nad4 of Oedocladium prescottii and B. rectangularis var. hiloensis were putative fast-evolving genes. These findings suggested that the traditional taxonomy of Oedogoniales did not define natural groups, and that species of Oedocladium and Bulbochaete may have undergone rapid evolution.
{"title":"Mitochondrial genome structure, phylogenetic analyses and substitution rate estimation of the Oedogoniales","authors":"Qian Xiong, Jiaqing Wang, Yuxin Hu, Qinghua Wang, Guoxiang Liu, Zhengyu Hu","doi":"10.1080/09670262.2022.2035825","DOIUrl":"https://doi.org/10.1080/09670262.2022.2035825","url":null,"abstract":"Abstract The order Oedogoniales comprises three genera, Oedogonium, Oedocladium and Bulbochaete, which were classified based on traditional morphological criteria, and includes more than 600 described species. This group is economically important in astaxanthin production and the energy sector. However, only one mitochondrial genome (mitogenome) has been reported so far. This study determined the mitochondrial genomes of seven Oedogoniales species, including six Oedogonium species and Oedocladium prescottii. Comparative analyses between the newly determined mitogenomes and the previously reported Bulbochaete rectangularis var. hiloensis mitogenome showed that all eight mitogenomes comprised 12 protein-coding genes (PCGs) and two rRNAs; however, the mitogenomes differed in their genome sizes, GC content, tRNAs, non-coding regions and introns. Synteny analysis of the eight mitogenomes revealed a high degree of syntenic conservation in general, with some rearrangements and inversions. The average nucleotide identity (ANI) analysis of the eight mitogenomes indicated Oedogonium dentireticulatum showed high similarity with Oedogonium sp3 (ANI of 96.32%). Most of the PCGs of the eight mitogenomes presented the conventional start codon ATG and stop codon TAR (TAA/TAG/TGA), and the synonymous codon preferences were conserved. Phylogenetic results indicated that Oedogonium was polyphyletic, and species of Oedocladium clustered with Oedogonium, while the position of B. rectangularis var. hiloensis was uncertain for the incongruent phylogenetic results. Statistical analyses of substitution rates demonstrated no significant differences among the three genera, and the dN/dS ratios based on branch model showed that cob, cox1 and nad4 of Oedocladium prescottii and B. rectangularis var. hiloensis were putative fast-evolving genes. These findings suggested that the traditional taxonomy of Oedogoniales did not define natural groups, and that species of Oedocladium and Bulbochaete may have undergone rapid evolution.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"1 - 12"},"PeriodicalIF":2.4,"publicationDate":"2022-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46571116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：