cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.20342882.v1
title: Parental environment modulates offspring thermal tolerance in a foundational intertidal seaweed

description: 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 (<i>Fucus guiryi</i>) 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 <i>F. guiryi</i> 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. Thermotolerance of <i>Fucus guiryi</i> 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. Thermotolerance of <i>Fucus guiryi</i> 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.
DOI: 10.6084/m9.figshare.20343464.v2
title: <i>Trebonskia zoosporica</i>, gen. et sp. nov., a new member of the Goniochloridales (Eustigmatophyceae, Stramenopiles) with an unusual mode of reproduction

description: A new freshwater microalgal isolate, CCALA 1135, was characterized using a polyphasic approach (morphology, ultrastructure, fatty acid composition, 18S rRNA gene and <i>rbc</i>L 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 <i>rbc</i>L 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, <i>Trebonskia zoosporica</i> 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. 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. 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.
DOI: 10.6084/m9.figshare.20368717
title: Cell fine structure and phylogeny of <i>Parvodinium</i>: towards an ultrastructural characterization of the Peridiniopsidaceae (Dinophyceae)

description: Recent molecular phylogenies that include species of <i>Parvodinium</i> revealed as its closest relatives the genera <i>Peridiniopsis, Palatinus</i> and <i>Johsia</i>. The clade containing these taxa is currently recognized as a family, Peridiniopsidaceae. The affinity between the members of Peridiniopsidaceae cuts across traditional boundaries based on features of the amphiesma, most notably the presence or absence of an apical pore complex. Detailed descriptions of the fine structure of <i>Peridiniopsis</i> and <i>Palatinus</i> are available from TEM studies of their type species. Here we provide a description in comparable detail of a species of the <i>Parvodinium umbonatum–inconspicuum</i> complex, which includes the type of the genus. The cells had an apical fibrous complex essentially similar to those described from other peridinioids prepared with comparable fixations. The pusular system was extensive and included areas with different aspects: an area with a sheet-like vesicle along the mid-right side of the cell, a ventral portion with ramified and anastomosed tubes and a somewhat flattened tube attached to the transverse flagellar canal. The most remarkable feature was the microtubular strand that extended from a ventral, protruding peduncle to the anterior part of the epicone, around an accumulation body, and came around along a more dorsal position toward the ventral side. This long microtubular strand of the peduncle (MSP) was reminiscent of the one described from <i>Peridiniopsis borgei</i>, both by its extension and looping path, and by the breaking up of the strand of microtubules into smaller portions with a wavy appearance; and contrasted with the reduced MSP of <i>Palatinus apiculatus</i>. The fine-structural features currently known from Peridiniopsidaceae are summarized. Members of the family include a flagellar apparatus with four microtubule-containing roots associated, the basal bodies inserted close to each other, nearly at right angles and a three-armed fibrous connective between root 1 and the transverse basal body. Detailed fine structure of <i>Parvodinium</i> (of <i>P. umbonatum–P. inconspicuum</i> complex).Comparative analysis of the ultrastructure of <i>Parvodinium</i> and other Peridiniopsidaceae.Summary of ultrastructural features of the family Peridiniopsidaceae. Detailed fine structure of <i>Parvodinium</i> (of <i>P. umbonatum–P. inconspicuum</i> complex). Comparative analysis of the ultrastructure of <i>Parvodinium</i> and other Peridiniopsidaceae. Summary of ultrastructural features of the family Peridiniopsidaceae.
DOI: 10.6084/m9.figshare.20368717.v1
title: Cell fine structure and phylogeny of <i>Parvodinium</i>: towards an ultrastructural characterization of the Peridiniopsidaceae (Dinophyceae)

description: Recent molecular phylogenies that include species of <i>Parvodinium</i> revealed as its closest relatives the genera <i>Peridiniopsis, Palatinus</i> and <i>Johsia</i>. The clade containing these taxa is currently recognized as a family, Peridiniopsidaceae. The affinity between the members of Peridiniopsidaceae cuts across traditional boundaries based on features of the amphiesma, most notably the presence or absence of an apical pore complex. Detailed descriptions of the fine structure of <i>Peridiniopsis</i> and <i>Palatinus</i> are available from TEM studies of their type species. Here we provide a description in comparable detail of a species of the <i>Parvodinium umbonatum–inconspicuum</i> complex, which includes the type of the genus. The cells had an apical fibrous complex essentially similar to those described from other peridinioids prepared with comparable fixations. The pusular system was extensive and included areas with different aspects: an area with a sheet-like vesicle along the mid-right side of the cell, a ventral portion with ramified and anastomosed tubes and a somewhat flattened tube attached to the transverse flagellar canal. The most remarkable feature was the microtubular strand that extended from a ventral, protruding peduncle to the anterior part of the epicone, around an accumulation body, and came around along a more dorsal position toward the ventral side. This long microtubular strand of the peduncle (MSP) was reminiscent of the one described from <i>Peridiniopsis borgei</i>, both by its extension and looping path, and by the breaking up of the strand of microtubules into smaller portions with a wavy appearance; and contrasted with the reduced MSP of <i>Palatinus apiculatus</i>. The fine-structural features currently known from Peridiniopsidaceae are summarized. Members of the family include a flagellar apparatus with four microtubule-containing roots associated, the basal bodies inserted close to each other, nearly at right angles and a three-armed fibrous connective between root 1 and the transverse basal body. Detailed fine structure of <i>Parvodinium</i> (of <i>P. umbonatum–P. inconspicuum</i> complex).Comparative analysis of the ultrastructure of <i>Parvodinium</i> and other Peridiniopsidaceae.Summary of ultrastructural features of the family Peridiniopsidaceae. Detailed fine structure of <i>Parvodinium</i> (of <i>P. umbonatum–P. inconspicuum</i> complex). Comparative analysis of the ultrastructure of <i>Parvodinium</i> and other Peridiniopsidaceae. Summary of ultrastructural features of the family Peridiniopsidaceae.
DOI: 10.6084/m9.figshare.20463943
title: Diversity, systematics and biogeography of French Polynesian <i>Lobophora</i> (Dictyotales, Phaeophyceae)

description: We re-evaluated the diversity of <i>Lobophora</i> using an integrative taxonomic approach based on a broad sampling across French Polynesian archipelagos. Our results show that French Polynesia supports at least 37 <i>Lobophora</i> species of which ~57% (21) are endemic. This level of endemicity is comparable to that presently known in the Caribbean and the western Indian Ocean, while French Polynesian coastlines cover a much smaller length. With a third of the species in common, French Polynesia shares considerable biogeographic affinities with the Melanesian Islands, situated over 4000 km to the west. Distribution ranges of a few species reach the western Indian Ocean, and two species also occur in the Atlantic. We hypothesize that <i>Lobophora</i> species in French Polynesia have mainly evolved into endemic species from colonizers originating from the Central Indo-Pacific. These rare dispersal events to ocean archipelagos followed by a long period of isolation and speciation represent an important process responsible for the high level of endemism in remote archipelagos. While south-eastern Pacific Islands could be considered an ‘evolutionary graveyard’ for the genus <i>Lobophora</i> as little local radiation occurred, this may simply be due to recent evolutionary history. Based on these new data, the diversity of <i>Lobophora</i> represents ~10% of French Polynesian seaweed diversity. Eighteen new species of <i>Lobophora</i> are here described from French Polynesia. <i>Lobophora</i> species diversity and biogeography in French Polynesia were investigated.Twenty-three species of <i>Lobophora</i> were newly identified, and 18 new species were described.This is the first inter-archipelago diversity and biogeographic study for a macroalgal genus in the French Polynesian region. <i>Lobophora</i> species diversity and biogeography in French Polynesia were investigated. Twenty-three species of <i>Lobophora</i> were newly identified, and 18 new species were described. This is the first inter-archipelago diversity and biogeographic study for a macroalgal genus in the French Polynesian region.
DOI: 10.6084/m9.figshare.20343464
title: <i>Trebonskia zoosporica</i>, gen. et sp. nov., a new member of the Goniochloridales (Eustigmatophyceae, Stramenopiles) with an unusual mode of reproduction

description: A new freshwater microalgal isolate, CCALA 1135, was characterized using a polyphasic approach (morphology, ultrastructure, fatty acid composition, 18S rRNA gene and <i>rbc</i>L 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 <i>rbc</i>L 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, <i>Trebonskia zoosporica</i> 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. 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. 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.
DOI: 10.6084/m9.figshare.20343464.v1
title: <i>Trebonskia zoosporica</i>, gen. et sp. nov., a new member of the <i>Goniochloridales</i> (Eustigmatophyceae, Stramenopiles) with an unusual mode of reproduction

description: A new freshwater microalgal isolate, CCALA 1135, was characterized using a polyphasic approach (morphology, ultrastructure, fatty acid composition, 18S rRNA gene and <i>rbc</i>L 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 <i>Goniochloridales</i> (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 <i>rbc</i>L sequences confirmed that CCALA 1135 represents a new member of <i>Goniochloridales</i> clade IIc. Based on cellular morphology, ultrastructure and molecular data we propose this strain as a new species and new genus of the Eustigmatophyceae, <i>Trebonskia zoosporica</i> 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. 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. 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.
DOI: 10.6084/m9.figshare.20367395
title: <i>Nannochloropsis oceanica</i> (Eustigmatophyceae) mutants resistant to rose bengal demonstrate high tolerance to oxygen

description: The genus <i>Nannochloropsis</i> (Eustigmatophyceae), including <i>N. oceanica</i>, has attracted considerable interest, due to its ability to accumulate high levels of lipids. Under large-scale cultivation outdoors, cells are exposed to a combination of high oxygen and light irradiance conditions that may promote photoinhibition, so selecting strains able to tolerate oxidative stress is desirable. Rose bengal (RB) reacts with oxygen to form singlet oxygen in the presence of light. Therefore, RB can be a very useful tool for testing the sensitivity of algae to oxidative stress and thus identify strains capable of photosynthesis under oxidative stress. In this study, two mutants of <i>N. oceanica</i>, RB2 and RB113, which are resistant to high concentrations of rose bengal, were phenotypically characterized for their sensitivity to high oxygen concentrations. Both strains exhibited levels of catalase and ascorbate peroxidase 1.5- and 3-fold higher, respectively, than the wild type. In addition, the synthesis of carotenoids was lower than in the wild type, indicating lower oxidative stress. These results were confirmed by chlorophyll fluorescence measurements, which indicated a lower sensitivity of the photosynthetic apparatus of the mutants, especially of RB2, even in the presence of H<sub>2</sub>O<sub>2</sub>. The results support the hypothesis that resistance to rose bengal may also induce resistance to high dissolved oxygen stress. The ability shown by the mutants to perform photosynthesis more efficiently under high oxygen stress than the wild type makes them promising candidates for outdoor cultures.
DOI: 10.6084/m9.figshare.20367395.v1
title: <i>Nannochloropsis oceanica</i> (Eustigmatophyceae) mutants resistant to rose bengal demonstrate high tolerance to oxygen

description: The genus <i>Nannochloropsis</i> (Eustigmatophyceae), including <i>N. oceanica</i>, has attracted considerable interest, due to its ability to accumulate high levels of lipids. Under large-scale cultivation outdoors, cells are exposed to a combination of high oxygen and light irradiance conditions that may promote photoinhibition, so selecting strains able to tolerate oxidative stress is desirable. Rose bengal (RB) reacts with oxygen to form singlet oxygen in the presence of light. Therefore, RB can be a very useful tool for testing the sensitivity of algae to oxidative stress and thus identify strains capable of photosynthesis under oxidative stress. In this study, two mutants of <i>N. oceanica</i>, RB2 and RB113, which are resistant to high concentrations of rose bengal, were phenotypically characterized for their sensitivity to high oxygen concentrations. Both strains exhibited levels of catalase and ascorbate peroxidase 1.5- and 3-fold higher, respectively, than the wild type. In addition, the synthesis of carotenoids was lower than in the wild type, indicating lower oxidative stress. These results were confirmed by chlorophyll fluorescence measurements, which indicated a lower sensitivity of the photosynthetic apparatus of the mutants, especially of RB2, even in the presence of H<sub>2</sub>O<sub>2</sub>. The results support the hypothesis that resistance to rose bengal may also induce resistance to high dissolved oxygen stress. The ability shown by the mutants to perform photosynthesis more efficiently under high oxygen stress than the wild type makes them promising candidates for outdoor cultures.
DOI: 10.6084/m9.figshare.20337524
title: Dynamic Cell Imaging: application to the diatom <i>Phaeodactylum tricornutum</i> under environmental stresses

description: The dynamic movement of cell organelles is an important and poorly understood component of cellular organization and metabolism. In this work we present a non-invasive non-destructive method (Dynamic Cell Imaging, DCI) based on light scattering and interferometry to monitor dynamic events within photosynthetic cells using the diatom <i>Phaeodactylum tricornutum</i> as a model system. For this monitoring we acquire for a few seconds movies of the signals that are related to the motion of dynamic structures within the cell (denoted scatterers), followed by a statistical analysis of each pixel time series. Illuminating <i>P. tricornutum</i> with LEDs of different wavelengths associated with short pulsed or continuous-wave modes of illumination revealed that dynamic movements depend on chloroplast activity, in agreement with the reduction in the number of pixels with dynamic behaviour after addition of photosystem II inhibitors. We studied <i>P. tricornutum</i> under two environmentally relevant stresses, iron and phosphate deficiency. The major dynamic sites were located within lipid droplets and chloroplast envelope membranes. By comparing standard deviation and cumulative sum analyses of the time series, we showed that within the droplets two types of scatterer movement could be observed: random motion (Brownian type) but also anomalous movements corresponding to a drift which may relate to molecular fluxes within a cell. The method appears to be valuable for studying the effects of various environments on microalgae in the laboratory as well as in natural aquatic environments. Light scattering is an alternative to fluorescence to rapidly evidence dynamic processes.Lipid droplets are the major metabolic active sites under stress.A non-destructive visualization method suitable for laboratory microalgae and aquatic samples. Light scattering is an alternative to fluorescence to rapidly evidence dynamic processes. Lipid droplets are the major metabolic active sites under stress. A non-destructive visualization method suitable for laboratory microalgae and aquatic samples.