Browsing by Author "Jacinto, Rita"
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- Algae as food in Europe: an overview of species diversity and their applicationPublication . Mendes, Madalena; Navalho, Sofia; Ferreira, Alice; Paulino, Cristina; Figueiredo, Daniel; Silva, Daniel; Gao, Fengzheng; Gama, Florinda; Bombo, Gabriel; Jacinto, Rita; Aveiro, Susana; Schulze, Peter S.C.; Gonçalves, Ana Teresa; Pereira, Hugo; Gouveia, Luisa; Patarra, Rita F.; Abreu, Maria Helena; Silva, Joana L.; Navalho, João; Varela, João; Galileu Speranza, LaisAlgae have been consumed for millennia in several parts of the world as food, food supplements, and additives, due to their unique organoleptic properties and nutritional and health benefits. Algae are sustainable sources of proteins, minerals, and fiber, with well-balanced essential amino acids, pigments, and fatty acids, among other relevant metabolites for human nutrition. This review covers the historical consumption of algae in Europe, developments in the current European market, challenges when introducing new species to the market, bottlenecks in production technology, consumer acceptance, and legislation. The current algae species that are consumed and commercialized in Europe were investigated, according to their status under the European Union (EU) Novel Food legislation, along with the market perspectives in terms of the current research and development initiatives, while evaluating the interest and potential in the European market. The regular consumption of more than 150 algae species was identified, of which only 20% are approved under the EU Novel Food legislation, which demonstrates that the current legislation is not broad enough and requires an urgent update. Finally, the potential of the European algae market growth was indicated by the analysis of the trends in research, technological advances, and market initiatives to promote algae commercialization and consumption.
- Carotenoid biosynthetic gene expression, pigment and n-3 fatty acid contents in carotenoid-rich Tetraselmis striata CTP4 strains under heat stress combined with high lightPublication . Schüler, Lisa Maylin; Bombo, Gabriel; Duarte, Paulo; Santos, Tamara; Maia, Inês Beatriz; Pinheiro, Filipa; Marques, José; Jacinto, Rita; Schulze, Peter S.C.; Pereira, Hugo; Barreira, Luísa; Varela, JoãoIn this study, two carotenoid-rich strains of the euryhaline microalga Tetraselmis striata CTP4 were isolated by random mutagenesis combined with selection via fluorescence activated cell sorting and growth on norflurazon. Both strains, ED5 and B11, showed an up to 1.5-fold increase in carotenoid contents as compared with the wildtype, independent of the growth conditions. More specifically, violaxanthin, beta-carotene and lutein contents reached as high as 1.63, 4.20 and 3.81 mg g-1 DW, respectively. Genes coding for phytoene synthase, phytoene desaturase, lycopene-beta-cyclase and epsilon-ring hydroxylase involved in carotenoid biosynthesis were found to be upregulated in ED5 and B11 cells as compared to the wildtype. Both strains showed higher contents of eicosapentaenoic acid as compared with those of the wildtype, reaching up to 4.41 and 2.88 mg g-1 DW, respectively. Overall, these results highlight the complexity of changes in carotenoid biosynthesis regulation that are required to improve pigment contents in microalgae.
- Congruence between fine-scale genetic breaks and dispersal potential in an estuarine seaweed across multiple transition zonesPublication . Nicastro, Katy; Assis, J.; Serrao, Ester; Pearson, Gareth; Neiva, J.; Valero, Myriam; Jacinto, Rita; Zardi, Gerardo, IGenetic structure in biogeographical transition zones can be shaped by several factors including limited dispersal across barriers, admixture following secondary contact, differential selection, and mating incompatibility. A striking example is found in Northwest France and Northwest Spain, where the estuarine seaweed Fucus ceranoides L. exhibits sharp, regional genetic clustering. This pattern has been related to historical population fragmentation and divergence into distinct glacial refugia, followed by post-glacial expansion and secondary contact. The contemporary persistence of sharp ancient genetic breaks between nearby estuaries has been attributed to prior colonization effects (density barriers) but the effect of oceanographic barriers has not been tested. Here, through a combination of mesoscale sampling (15 consecutive populations) and population genetic data (mtIGS) in NW France, we define regional genetic disjunctions similar to those described in NW Iberia. Most importantly, using high resolution dispersal simulations for Brittany and Iberian populations, we provide evidence for a central role of contemporary hydrodynamics in maintaining genetic breaks across these two major biogeographic transition zones. Our findings further show the importance of a comprehensive understanding of oceanographic regimes in hydrodynamically complex coastal regions to explain the maintenance of sharp genetic breaks along continuously populated coastlines.
- Enhancement of heat tolerance by salt stress in Tetraselmis striata CTP4: impacts on HSP gene expression, pigments, and proximal compositionPublication . Santos, Tamara; Pereira, Hugo; Maia, Inês Beatriz; Jacinto, Rita; Bombo, Gabriel; Pinheiro, Filipa Maria Ribeiro; Barreira, Luísa; Varela, JoãoAs the world average temperature is on the rise and heat waves are becoming more prevalent, microalgal producers have been facing significant challenges regarding the time periods during which they are able to grow less thermotolerant microalgae in outdoor production facilities. Therefore, it is urgent to explore how microalgae cope with thermal stress and under which growth conditions tolerance to temperatures close to or higher than their maximum thermal threshold is induced. For this purpose, Tetraselmis striata CTP4, a euryhaline microalga known for its thermotolerance, was selected. Tetraselmis striata belongs to the Chlorodendrophyceae, a clade that branched off early from other "core chlorophyte" clades, usually comprised of microalgae able to colonise freshwater habitats. Here, we present compelling evidence that the ability of this microalga to withstand otherwise lethal thermal upshifts to 40 degrees C is induced by exposure to higher salinity (35 ppt). In contrast, this response is abrogated at lower salinities. Concomitantly, the expression of genes encoding HSP70 and HSP100, two heat shock proteins known to mediate thermotolerance and tolerance to other stresses (e.g., salt stress) in fungi, animals and plants, was enhanced when exposed to both heat stress and higher salinities. This suggests that cross-protective mechanisms against abiotic stress appeared early during the evolution of the core chlorophytes and of Archaeplastida in general. This knowledge can be used to select novel strains and growth conditions that promote thermotolerance in microalgae that are grown in outdoor industrial production facilities in environments where heat waves are expected.
- Increased evolutionary rates and conserved transcriptional response following allopolyploidization in brown algaePublication . Sousa, Filipe; Neiva, J.; Martins, Neusa; Jacinto, Rita; Anderson, Laura; Raimondi, Peter T.; Serrao, Ester; Pearson, GarethGenome mergers between independently evolving lineages, via allopolyploidy, can potentially lead to instantaneous sympatric speciation. However, little is known about the consequences of allopolyploidy and the resultant "genome shock" on genome evolution and expression beyond the plant and fungal branches of the Tree of Life. The aim of this study was to compare substitution rates and gene expression patterns in two allopolyploid brown algae (Phaeophyceae and Heterokonta) and their progenitors in the genus Pelvetiopsis N. L. Gardner in the north-east Pacific, and to date their relationships. We used RNA-seq data, all potential orthologues, and putative single-copy loci for phylogenomic, divergence, and gene expression analyses. The multispecies coalescent placed the origin of allopolyploids in the late Pleistocene (0.35-0.05 Ma). Homoeologues displayed increased nonsynonymous divergence compared with parental orthologues, consistent with relaxed selective constraint following allopolyploidization, including for genes with no evidence of pseudogenization or neofunctionalization. Patterns of homoeologue-orthologue expression conservation and expression level dominance were largely shared with both natural plant and fungal allopolyploids. Our results provide further support for common cross-Kingdom patterns of allopolyploid genome evolution and transcriptional responses, here in the evolutionarily distinct marine heterokont brown algae.
- Taking the heat: distinct vulnerability to thermal stress of central and threatened peripheral lineages of a marine macroalgaPublication . Saada, Gabriel; Nicastro, Katy R; Jacinto, Rita; McQuaid, Christopher D.; Serrão, Ester; Pearson, G. A.; Zardi, Gerardo I.Aim Although many studies have reported the effects of climate change on species' distributions, most of them consider each species as a physiologically homogenous unit. However, different lineages or populations inhabiting distinct bioregions within a species' distributional range can retain unique genetic diversity that could result in distinct adaptive capacities. A recent, large, climate-correlated distributional range contraction occurred at the southern edge of the intertidal macroalga Fucus vesiculosus, causing loss of genetic diversity unique to the southern clade. We tested for differential selective constraints and signs of local adaptation to thermal stress in the two genetic lineages.Location Iberian Atlantic shores.Methods We performed a series of common garden experiments and a field reciprocal transplant.Results In the laboratory, southern F. vesiculosus showed higher resilience to heat stress than northern individuals. On the southwest coast of Portugal, local individuals grew more than those transplanted from the northern range; in the north of Portugal, growth rates did not differ significantly between lineages.Conclusions We present evidence for unique adaptive traits at the retreating edge of the species' distribution that could be lost if warming trends persist. The loss of the distinct southern genetic heritage could end potential ongoing diversification or speciation processes and impoverishes the adaptive potential of the species as a whole.
- Temporal windows of reproductive opportunity reinforce species barriers in a marine broadcast spawning assemblagePublication . Monteiro, Carla A.; Paulino, Cristina; Jacinto, Rita; Serrão, Ester; Pearson, GarethPrezygotic isolating mechanisms act to limit hybridization and maintain the genetic identity of closely-related species. While synchronous intraspecific spawning is a common phenomenon amongst marine organisms and plays an important role in reproductive success, asynchronous spawning between potentially hybridizing lineages may also be important in maintaining species boundaries. We tested this hypothesis by comparing reproductive synchrony over daily to hourly timescales in a sympatric assemblage of intertidal fucoid algae containing selfing hermaphroditic (Fucus spiralis and Fucus guiryi) and dioecious (Fucus vesiculosus and Fucus serratus) species. Our results confirm that gametes are released on semi-lunar cycles in all species. However, sister species with different mating systems showed asynchronous spawning at finer circadian timescales, thus providing evidence for a partial reproductive barrier between hermaphroditic and dioecious species. Finally, our data also emphasize the ecological, developmental, and/or physiological constraints that operate to restrict reproduction to narrow temporal windows of opportunity in the intertidal zone and more generally the role of ecological factors in marine speciation.
- Upwelling areas as climate change refugia for the distribution and genetic diversity of a marine macroalgaPublication . Lourenço, Carla R.; Zardi, Gerardo I.; McQuaid, Christopher D.; Serrão, Ester; Pearson, Gareth; Jacinto, Rita; Nicastro, Katy RAimGlobal climate change has profound and diverse effects on biological diversity. Identifying present-day climate refugia is an increasingly recognized strategy for the management of biodiversity loss. Such refugia are potential safe havens that enhance environmental diversity by buffering the effects of large scale change, facilitating species persistence at regional scales and conserving unique genetic diversity. Although their ecological effects are well studied, the potential of upwelling centres to act as refugia in a scenario of climate warming remains largely unexplored. Here, we investigate whether upwelled waters act as refugia in a region heavily affected by recent climatic changes.LocationShores of south-western Iberia and north-western Africa.MethodsWe compared changes in distribution of the canopy-forming macroalga Fucus guiryi with sea surface temperature patterns in five upwelling areas and adjacent warmer regions. Population diversity and structure was inferred from genotypic analyses using nine microsatellite loci.ResultsFucus guiryi has disappeared from large expanses of non-upwelling shores, currently persisting in areas characterized by strong upwelling and reduced or non-significant rates of warming. Populations of F. guiryi were more abundant towards upwelling centres. Furthermore, the genetic characterization of populations revealed distinct genetic groups associated with each upwelling system.Main conclusionsWithin a large region of predominantly changing climate, we highlight the fundamental importance of upwelling areas as favourable, comparatively stable climates where F. guiryi has retreated and persists, preserving unique portions of the species' genetic pool.