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Santiago P. Aubourg - One of the best experts on this subject based on the ideXlab platform.
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impact of previous active dipping in Fucus spiralis extract on the quality enhancement of chilled lean fish
Food Control, 2018Co-Authors: José M. Miranda, Jorge Barrosvelazquez, Monica Carrera, Santiago P. AubourgAbstract:Abstract The first goal of this work was to enhance the quality of chilled fish by applying a preliminary dipping treatment containing a bioactive extract from the alga Fucus spiralis. Megrim (Lepidorhombus whiffiagonis) specimens were dipped in aqueous solutions containing two different concentrations of the alga extract (0.50% and 0.10% alga/dipping solution, w/v; HAC and LAC batches, respectively). In addition, two control batches were considered (water dipping control and no dipping control). Microbial, chemical and sensory qualities were assessed in fish specimens after 0, 2, 6, 9 and 13 days of chilled storage. An antimicrobial effect at advanced stages of storage (9–13-day period) was observed as determined by the comparative evolution of aerobes, psychrotrophs and Enterobacteriaceae counts in megrim muscle. Likewise, a protective effect against specific lipolytic and proteolytic spoilage bacteria was also achieved at that storage period, as well as a decrease of free fatty acids formation. However, alga extract in the dipping medium had no effect (p > 0.05) on the increase of lipid oxidation in fish muscle throughout chilled storage. Interestingly, average scores revealed improved sensory quality in megrim corresponding to the HAC batch for the 9–13-day chilled period. Consequently, the proposed novel dipping treatment can be considered of interest for both on-board and in-land fish storage, due to the simple methodology employed and the resulting protective effects on fish quality.
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Impact of icing systems with aqueous, ethanolic and ethanolic‐aqueous extracts of alga Fucus spiralis on microbial and biochemical quality of chilled hake (Merluccius merluccius)
International Journal of Food Science and Technology, 2016Co-Authors: Jorge Barros-velázquez, José M. Miranda, Josafat Marina Ezquerra-brauer, Santiago P. AubourgAbstract:Summary The study focuses on the impact of icing systems with aqueous (AQ batch), ethanolic (ET batch) and ethanolic-aqueous (ET-AQ batch) extracts of alga Fucus spiralis on the microbial and biochemical quality of chilled hake (Merluccius merluccius). After a 13-day storage, comparison with fish kept under traditional ice proved a significant (P
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impact of icing systems with aqueous ethanolic and ethanolic aqueous extracts of alga Fucus spiralis on microbial and biochemical quality of chilled hake merluccius merluccius
International Journal of Food Science and Technology, 2016Co-Authors: Jorge Barrosvelazquez, José M. Miranda, Josafat Marina Ezquerrabrauer, Santiago P. AubourgAbstract:Summary The study focuses on the impact of icing systems with aqueous (AQ batch), ethanolic (ET batch) and ethanolic-aqueous (ET-AQ batch) extracts of alga Fucus spiralis on the microbial and biochemical quality of chilled hake (Merluccius merluccius). After a 13-day storage, comparison with fish kept under traditional ice proved a significant (P < 0.05) antimicrobial effect against aerobes, psychrotrophs, proteolytic and lipolytic bacteria, derived of the presence of F. spiralis ethanolic extracts in the icing medium (ET and ET-AQ batches). Additionally, an inhibitory effect of both ethanol extracts was also obtained concerning lipid oxidation development (i.e. secondary and tertiary lipid oxidation compounds). Additionally, lipid damage assessment showed lower mean values in tertiary oxidation compound formation in hake belonging to the ET-AQ batch throughout the whole storage period. Present research indicates that ET-AQ ice condition can lead to a marked quality and safety enhancement as well as to profitable commercial value increases.
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effect of an icing medium containing the alga Fucus spiralis on the microbiological activity and lipid oxidation in chilled megrim lepidorhombus whiffiagonis
Food Control, 2016Co-Authors: José M. Miranda, Marcos Trigo, Jorge Barrosvelazquez, Santiago P. AubourgAbstract:Abstract The present study provides a first approach on the employment of an icing medium including Fucus spiralis, an alga exhibiting antimicrobial and antioxidant activities, for the preservation of fish quality during chilled storage. For it, two different concentrations of a F. spiralis extract (0.67 and 2.50 g lyophilized alga L−1 aqueous solution; F-1 and F-2 batches, respectively) were tested as icing medium for the chilled storage of megrim (Lepidorhombus whiffiagonis) for 14 days. The effects of the alga were compared with a counterpart batch stored in traditional ice prepared only from water (F-0 batch). A significant (p
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effect of biodegradable film lyophilised alga Fucus spiralis and sorbic acid on quality properties of refrigerated megrim lepidorhombus whiffiagonis
International Journal of Food Science and Technology, 2015Co-Authors: Bibiana Garciasoto, José M. Miranda, Jorge Barrosvelazquez, Ana Rodriguezbernaldo De Quiros, R Sendon, Ana V Rodriguezmartinez, Santiago P. AubourgAbstract:Summary The effect of replacing the on-board currently employed polyethylene film by a novel type of environmentally friendly packaging was studied. For it, a polylactic acid (PLA) biodegradable film including lyophilised alga Fucus spiralis and sorbic acid was applied during megrim (Lepidorhombus whiffiagonis) refrigeration and its effect on fish quality loss was evaluated. Thus, sensory assessment showed that samples wrapped up with PLA film including 8% alga and 1% sorbic acid were still acceptable on day 11, while control fish specimens (kept under polyethylene film) were rejected at that time. Under such biodegradable film condition, a preservative effect was also implied according to chemical indices assessment related to microbial activity (trimethylamine–N) and lipid oxidation development (peroxide and fluorescent compounds formation); additionally, lower mean numbers for different microbiological groups (aerobes, Enterobacteriaceae and psychrotrophs) were detected. This result provides a promising replacement strategy to enhance refrigerated fish quality and reduce the waste material content.
Ester A Serrao - One of the best experts on this subject based on the ideXlab platform.
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Polymorphic microsatellite markers in the brown seaweed Fucus vesiculosus
BMC Research Notes, 2015Co-Authors: Rui Candeias, Gareth A Pearson, Ester A Serrao, Pilar Casado-amezúa, Sara TeixeiraAbstract:Background Fucus vesiculosus is a brown seaweed dominant on temperate rocky shores of the northern hemisphere and, is typically distributed in the mid-upper intertidal zone. It is an external fertilizer that reproduces sexually, providing an excellent model to address conflicting theories related to mating systems and sexual selection. Microsatellite markers have been reported for several Fucus species, however the genomic libraries from where these markers have been isolated, have originated from two or more species pooled together (F. vesiculosus and F. serratus in one library; F. vesiculosus, F. serratus and Ascophyllum nodosum in a second library), or when the genomic DNA originated from only one species it was from Fucus spiralis. Although these markers cross-amplify F. vesiculosus individuals, the level of polymorphism has been low for relatedness studies.
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evolution and diversification within the intertidal brown macroalgae Fucus spiralis f vesiculosus species complex in the north atlantic
Molecular Phylogenetics and Evolution, 2011Co-Authors: James A Coyer, Gareth A Pearson, Ester A Serrao, Galice Hoarau, Joana Costa, B Hogerdijk, E Billard, Myriam Valero, Jeanine L OlsenAbstract:We examined 733 individuals of Fucus spiralis from 21 locations and 1093 Fucus vesiculosus individuals from 37 locations throughout their northern hemisphere ranges using nuclear and mitochondrial markers. Three genetic entities of F. spiralis were recovered. In northern and sympatric populations, the presence of ‘‘F. spiralis Low’’ in the mid-intertidal and ‘‘F. spiralis High’’ in the high-intertidal was confirmed and both co-occurred with the sister species F. vesiculosus. The third and newly-discovered entity, ‘‘F. spiralis South’’, was present mainly in the southern range, where it did not co-occur with F. vesiculosus. The South entity diverged early in allopatry, then hybridized with F. vesiculosus in sympatry to produce F. spiralis Low. Ongoing parallel evolution of F. spiralis Low and F. spiralis High is most likely due to habitat preference/local selection and maintained by preferentially selfing reproductive strategies. Contemporary populations of F. spiralis throughout the North Atlantic stem from a glacial refugium around Brittany involving F. spiralis High; F. spiralis South was probably unaffected by glacial episodes. Exponential population expansion for F. vesiculosus began during the Cromer and/Holstein interglacial period (300,000– 200,000 yrs BP). Following the last glacial maximum (30,000–22,000 yrs BP), a single mtDNA haplotype from a glacial refugium in SW Ireland colonized Scandinavia, the Central Atlantic islands, and the W
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Evolution and diversification within the intertidal brown macroalgae Fucus spiralis/F. vesiculosus species complex in the North Atlantic.
Molecular Phylogenetics and Evolution, 2010Co-Authors: James A Coyer, Gareth A Pearson, Ester A Serrao, Galice Hoarau, Joana Costa, B Hogerdijk, E Billard, Myriam Valero, Jeanine L OlsenAbstract:We examined 733 individuals of Fucus spiralis from 21 locations and 1093 Fucus vesiculosus individuals from 37 locations throughout their northern hemisphere ranges using nuclear and mitochondrial markers. Three genetic entities of F. spiralis were recovered. In northern and sympatric populations, the presence of ‘‘F. spiralis Low’’ in the mid-intertidal and ‘‘F. spiralis High’’ in the high-intertidal was confirmed and both co-occurred with the sister species F. vesiculosus. The third and newly-discovered entity, ‘‘F. spiralis South’’, was present mainly in the southern range, where it did not co-occur with F. vesiculosus. The South entity diverged early in allopatry, then hybridized with F. vesiculosus in sympatry to produce F. spiralis Low. Ongoing parallel evolution of F. spiralis Low and F. spiralis High is most likely due to habitat preference/local selection and maintained by preferentially selfing reproductive strategies. Contemporary populations of F. spiralis throughout the North Atlantic stem from a glacial refugium around Brittany involving F. spiralis High; F. spiralis South was probably unaffected by glacial episodes. Exponential population expansion for F. vesiculosus began during the Cromer and/Holstein interglacial period (300,000– 200,000 yrs BP). Following the last glacial maximum (30,000–22,000 yrs BP), a single mtDNA haplotype from a glacial refugium in SW Ireland colonized Scandinavia, the Central Atlantic islands, and the W
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implications of mating system for genetic diversity of sister algal species Fucus spiralis and Fucus vesiculosus heterokontophyta phaeophyceae
European Journal of Phycology, 2007Co-Authors: Cecile Perrin, Claire Daguin, Mirjam Van De Vliet, Carolyn R Engel, Gareth A Pearson, Ester A SerraoAbstract:The implications of mating system for genetic diversity were assessed in the sister species Fucus spiralis and Fucus vesiculosus using a combination of ten microsatellite markers. Five new microsatellite markers specific for F. spiralis were developed in order to increase marker resolution and complement the results (i.e. mating system and genetic diversity extended to a larger geographic scale) acquired using five microsatellite loci previously developed from a mixed fucoid seaweed DNA library that excluded F. spiralis. Low genetic diversities observed at the population and species level in F. spiralis using the five new F. spiralis-specific loci described here were consistent with the results obtained previously with non-specific microsatellite loci. Results revealed that selfing is characteristic in F. spiralis across its latitudinal distribution along the Iberian and French Atlantic coasts. Higher levels of within-population genetic diversity were observed in the outcrossing species F. vesiculosus, de...
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Convergent adaptation to a marginal habitat by homoploid hybrids and polyploid ecads in the seaweed genus Fucus
Biology Letters, 2006Co-Authors: James A Coyer, Gareth A Pearson, Ester A Serrao, Galice Hoarau, Wytze T. Stam, Jeanine L OlsenAbstract:Hybridization and polyploidy are two major sources of genetic variability that can lead to adaptation in new habitats. Most species of the brown algal genus Fucus are found along wave-swept rocky shores of the Northern Hemisphere, but some species have adapted to brackish and salt marsh habitats. Using five microsatellite loci and mtDNA RFLP, we characterize two populations of morphologically similar, muscoides-like Fucus inhabiting salt marshes in Iceland and Ireland. The Icelandic genotypes were consistent with Fucus vesiculosus×Fucus spiralis F1 hybrids with asymmetrical hybridization, whereas the Irish ones consisted primarily of polyploid F. vesiculosus.
Michelle S Tierney - One of the best experts on this subject based on the ideXlab platform.
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uplc ms profiling of low molecular weight phlorotannin polymers in ascophyllum nodosum pelvetia canaliculata and Fucus spiralis
Metabolomics, 2014Co-Authors: Michelle S Tierney, Anna Solervila, Anna K Croft, Nigel P Brunton, Thomas J SmythAbstract:Phlorotannins are a group of complex polymers, found in particular brown macroalgae, composed solely of the monomer phloroglucinol (1,3,5-trihydroxybenzene). Their structural complexity arises from the number of possible linkage positions between each monomer unit. This study aimed to profile the phlorotannin metabolite composition and the complexity of isomerisation present in brown macroalgae Ascophyllum nodosum, Pelvetia canaliculata and Fucus spiralis using UPLC-MS utilising a tandem quadrupole mass spectrometer. Phlorotannin-enriched fractions from water and aqueous ethanol extracts were analysed by UPLC-MS performed in multiple reaction monitoring mode to detect molecular ions consistent with the molecular weights of phlorotannins. Ascophyllum nodosum and P. canaliculata appeared to contain predominantly larger phlorotannins (degree of polymerisation (DP) of 6–13 monomers) compared to F. spiralis (DP of 4–6 monomers). This is the first report observing the complex chromatographic separation and metabolomic profiling of low molecular weight phlorotannins consisting of more than ten monomers. Extracted ion chromatograms, for each of the MRM transitions, for each species were analysed to profile the level of isomerisation for specific molecular weights of phlorotannins between 3 and 16 monomers. The level of phlorotannin isomerisation within the extracts of the individual macroalgal species differed to some degree, resulting in substantially different numbers of phlorotannin isomers for particular molecular weights. A similar UPLC-MS/MS separation procedure, as outlined in this study, may be used in the future as a means of screening the metabolite profile of macroalgal extracts, therefore, allowing extract consistency to be monitored for standardisation purposes.
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antioxidant activity of the brown macroalgae Fucus spiralis linnaeus harvested from the west coast of ireland
Current Research Journal of Biological Sciences, 2013Co-Authors: Michelle S Tierney, Anna Solervila, Anna K Croft, Maria HayesAbstract:The extraction and isolation of natural antioxidants with potential in reducing the incidences of oxidative stress in the body and their potential inclusion into functional foods is a major topic of research at present. In this study, the aim was to investigate food-friendly Accelerated Solvent Extraction ® (ASE ® ) samples and a Viscozyme ® hydrolysate of the brown macroalga Fucus spiralis Linnaeus for total phenolic content and antioxidant activities. Furthermore, the effect of ultra-filtration steps on the total phenolic content and antioxidant activities of the Fucus spiralis hydrolysate were also evaluated. Fucus spiralis ethanolic-aqueous and methanolic-aqueous ASE ® extracts displayed high phenolic contents of 37.03±3.01 and 39.04±5.72 µg phloroglucinol equivalents mg/sample, respectively. Both the Fucus spiralis Viscozyme ® hydrolysate and ASE ® extracts displayed in vitro antioxidant activities. Our findings suggest that food-friendly extracts of Fucus spiralis show potential as alternative sources of antioxidants.
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Influence of pressurised liquid extraction and solid–liquid extraction methods on the phenolic content and antioxidant activities of Irish macroalgae
International Journal of Food Science and Technology, 2012Co-Authors: Michelle S Tierney, Anna K Croft, Maria Hayes, Thomas J Smyth, Anna Soler-vila, Nigel P BruntonAbstract:Summary The efficiencies of pressurised liquid extraction (PLE) and a traditional solid–liquid extraction (SLE) at extracting antioxidant polyphenols from Irish macroalgae Ascophyllum nodosum, Pelvetia canaliculata, Fucus spiralis and Ulva intestinalis were compared. PLE was more effective for extracting polyphenols with acetone/water (80:20); however, when food-friendly solvents of ethanol/water (80:20) and water were employed, SLE resulted in higher phenolic content in brown macroalgal extracts. For example, the Fucus spiralis SLE water and ethanol/water extracts displayed total phenolic contents (TPCs) of 130.58 ± 2.78 and 142.81 ± 1.77 μg phloroglucinol equivalents (PGE) mg−1 sample, respectively, compared with TPCs of 90.79 ± 1.16 and 124 ± 6.54 μg PGE mg−1 sample for the corresponding PLE extracts. All SLE aqueous ethanolic macroalgal extracts possessed higher DPPH radical scavenging abilities (RSA) and ferric reducing antioxidant power (FRAP) than their PLE equivalents. This study indicates that the application of high extraction temperatures (50–200 °C) and pressures (500–3000 psi) used in PLE does not enhance the antioxidant activities of macroalgal extracts relative to SLE extraction. The ability to produce antioxidant food-friendly macroalgal extracts using SLE could represent significant cost reductions on an industrial scale further enhancing the potential of macroalgal polyphenols to be used in functional food preparations.
José M. Miranda - One of the best experts on this subject based on the ideXlab platform.
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impact of previous active dipping in Fucus spiralis extract on the quality enhancement of chilled lean fish
Food Control, 2018Co-Authors: José M. Miranda, Jorge Barrosvelazquez, Monica Carrera, Santiago P. AubourgAbstract:Abstract The first goal of this work was to enhance the quality of chilled fish by applying a preliminary dipping treatment containing a bioactive extract from the alga Fucus spiralis. Megrim (Lepidorhombus whiffiagonis) specimens were dipped in aqueous solutions containing two different concentrations of the alga extract (0.50% and 0.10% alga/dipping solution, w/v; HAC and LAC batches, respectively). In addition, two control batches were considered (water dipping control and no dipping control). Microbial, chemical and sensory qualities were assessed in fish specimens after 0, 2, 6, 9 and 13 days of chilled storage. An antimicrobial effect at advanced stages of storage (9–13-day period) was observed as determined by the comparative evolution of aerobes, psychrotrophs and Enterobacteriaceae counts in megrim muscle. Likewise, a protective effect against specific lipolytic and proteolytic spoilage bacteria was also achieved at that storage period, as well as a decrease of free fatty acids formation. However, alga extract in the dipping medium had no effect (p > 0.05) on the increase of lipid oxidation in fish muscle throughout chilled storage. Interestingly, average scores revealed improved sensory quality in megrim corresponding to the HAC batch for the 9–13-day chilled period. Consequently, the proposed novel dipping treatment can be considered of interest for both on-board and in-land fish storage, due to the simple methodology employed and the resulting protective effects on fish quality.
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Impact of icing systems with aqueous, ethanolic and ethanolic‐aqueous extracts of alga Fucus spiralis on microbial and biochemical quality of chilled hake (Merluccius merluccius)
International Journal of Food Science and Technology, 2016Co-Authors: Jorge Barros-velázquez, José M. Miranda, Josafat Marina Ezquerra-brauer, Santiago P. AubourgAbstract:Summary The study focuses on the impact of icing systems with aqueous (AQ batch), ethanolic (ET batch) and ethanolic-aqueous (ET-AQ batch) extracts of alga Fucus spiralis on the microbial and biochemical quality of chilled hake (Merluccius merluccius). After a 13-day storage, comparison with fish kept under traditional ice proved a significant (P
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impact of icing systems with aqueous ethanolic and ethanolic aqueous extracts of alga Fucus spiralis on microbial and biochemical quality of chilled hake merluccius merluccius
International Journal of Food Science and Technology, 2016Co-Authors: Jorge Barrosvelazquez, José M. Miranda, Josafat Marina Ezquerrabrauer, Santiago P. AubourgAbstract:Summary The study focuses on the impact of icing systems with aqueous (AQ batch), ethanolic (ET batch) and ethanolic-aqueous (ET-AQ batch) extracts of alga Fucus spiralis on the microbial and biochemical quality of chilled hake (Merluccius merluccius). After a 13-day storage, comparison with fish kept under traditional ice proved a significant (P < 0.05) antimicrobial effect against aerobes, psychrotrophs, proteolytic and lipolytic bacteria, derived of the presence of F. spiralis ethanolic extracts in the icing medium (ET and ET-AQ batches). Additionally, an inhibitory effect of both ethanol extracts was also obtained concerning lipid oxidation development (i.e. secondary and tertiary lipid oxidation compounds). Additionally, lipid damage assessment showed lower mean values in tertiary oxidation compound formation in hake belonging to the ET-AQ batch throughout the whole storage period. Present research indicates that ET-AQ ice condition can lead to a marked quality and safety enhancement as well as to profitable commercial value increases.
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effect of an icing medium containing the alga Fucus spiralis on the microbiological activity and lipid oxidation in chilled megrim lepidorhombus whiffiagonis
Food Control, 2016Co-Authors: José M. Miranda, Marcos Trigo, Jorge Barrosvelazquez, Santiago P. AubourgAbstract:Abstract The present study provides a first approach on the employment of an icing medium including Fucus spiralis, an alga exhibiting antimicrobial and antioxidant activities, for the preservation of fish quality during chilled storage. For it, two different concentrations of a F. spiralis extract (0.67 and 2.50 g lyophilized alga L−1 aqueous solution; F-1 and F-2 batches, respectively) were tested as icing medium for the chilled storage of megrim (Lepidorhombus whiffiagonis) for 14 days. The effects of the alga were compared with a counterpart batch stored in traditional ice prepared only from water (F-0 batch). A significant (p
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effect of biodegradable film lyophilised alga Fucus spiralis and sorbic acid on quality properties of refrigerated megrim lepidorhombus whiffiagonis
International Journal of Food Science and Technology, 2015Co-Authors: Bibiana Garciasoto, José M. Miranda, Jorge Barrosvelazquez, Ana Rodriguezbernaldo De Quiros, R Sendon, Ana V Rodriguezmartinez, Santiago P. AubourgAbstract:Summary The effect of replacing the on-board currently employed polyethylene film by a novel type of environmentally friendly packaging was studied. For it, a polylactic acid (PLA) biodegradable film including lyophilised alga Fucus spiralis and sorbic acid was applied during megrim (Lepidorhombus whiffiagonis) refrigeration and its effect on fish quality loss was evaluated. Thus, sensory assessment showed that samples wrapped up with PLA film including 8% alga and 1% sorbic acid were still acceptable on day 11, while control fish specimens (kept under polyethylene film) were rejected at that time. Under such biodegradable film condition, a preservative effect was also implied according to chemical indices assessment related to microbial activity (trimethylamine–N) and lipid oxidation development (peroxide and fluorescent compounds formation); additionally, lower mean numbers for different microbiological groups (aerobes, Enterobacteriaceae and psychrotrophs) were detected. This result provides a promising replacement strategy to enhance refrigerated fish quality and reduce the waste material content.
Jeanine L Olsen - One of the best experts on this subject based on the ideXlab platform.
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evolution and diversification within the intertidal brown macroalgae Fucus spiralis f vesiculosus species complex in the north atlantic
Molecular Phylogenetics and Evolution, 2011Co-Authors: James A Coyer, Gareth A Pearson, Ester A Serrao, Galice Hoarau, Joana Costa, B Hogerdijk, E Billard, Myriam Valero, Jeanine L OlsenAbstract:We examined 733 individuals of Fucus spiralis from 21 locations and 1093 Fucus vesiculosus individuals from 37 locations throughout their northern hemisphere ranges using nuclear and mitochondrial markers. Three genetic entities of F. spiralis were recovered. In northern and sympatric populations, the presence of ‘‘F. spiralis Low’’ in the mid-intertidal and ‘‘F. spiralis High’’ in the high-intertidal was confirmed and both co-occurred with the sister species F. vesiculosus. The third and newly-discovered entity, ‘‘F. spiralis South’’, was present mainly in the southern range, where it did not co-occur with F. vesiculosus. The South entity diverged early in allopatry, then hybridized with F. vesiculosus in sympatry to produce F. spiralis Low. Ongoing parallel evolution of F. spiralis Low and F. spiralis High is most likely due to habitat preference/local selection and maintained by preferentially selfing reproductive strategies. Contemporary populations of F. spiralis throughout the North Atlantic stem from a glacial refugium around Brittany involving F. spiralis High; F. spiralis South was probably unaffected by glacial episodes. Exponential population expansion for F. vesiculosus began during the Cromer and/Holstein interglacial period (300,000– 200,000 yrs BP). Following the last glacial maximum (30,000–22,000 yrs BP), a single mtDNA haplotype from a glacial refugium in SW Ireland colonized Scandinavia, the Central Atlantic islands, and the W
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Evolution and diversification within the intertidal brown macroalgae Fucus spiralis/F. vesiculosus species complex in the North Atlantic.
Molecular Phylogenetics and Evolution, 2010Co-Authors: James A Coyer, Gareth A Pearson, Ester A Serrao, Galice Hoarau, Joana Costa, B Hogerdijk, E Billard, Myriam Valero, Jeanine L OlsenAbstract:We examined 733 individuals of Fucus spiralis from 21 locations and 1093 Fucus vesiculosus individuals from 37 locations throughout their northern hemisphere ranges using nuclear and mitochondrial markers. Three genetic entities of F. spiralis were recovered. In northern and sympatric populations, the presence of ‘‘F. spiralis Low’’ in the mid-intertidal and ‘‘F. spiralis High’’ in the high-intertidal was confirmed and both co-occurred with the sister species F. vesiculosus. The third and newly-discovered entity, ‘‘F. spiralis South’’, was present mainly in the southern range, where it did not co-occur with F. vesiculosus. The South entity diverged early in allopatry, then hybridized with F. vesiculosus in sympatry to produce F. spiralis Low. Ongoing parallel evolution of F. spiralis Low and F. spiralis High is most likely due to habitat preference/local selection and maintained by preferentially selfing reproductive strategies. Contemporary populations of F. spiralis throughout the North Atlantic stem from a glacial refugium around Brittany involving F. spiralis High; F. spiralis South was probably unaffected by glacial episodes. Exponential population expansion for F. vesiculosus began during the Cromer and/Holstein interglacial period (300,000– 200,000 yrs BP). Following the last glacial maximum (30,000–22,000 yrs BP), a single mtDNA haplotype from a glacial refugium in SW Ireland colonized Scandinavia, the Central Atlantic islands, and the W
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Convergent adaptation to a marginal habitat by homoploid hybrids and polyploid ecads in the seaweed genus Fucus
Biology Letters, 2006Co-Authors: James A Coyer, Gareth A Pearson, Ester A Serrao, Galice Hoarau, Wytze T. Stam, Jeanine L OlsenAbstract:Hybridization and polyploidy are two major sources of genetic variability that can lead to adaptation in new habitats. Most species of the brown algal genus Fucus are found along wave-swept rocky shores of the Northern Hemisphere, but some species have adapted to brackish and salt marsh habitats. Using five microsatellite loci and mtDNA RFLP, we characterize two populations of morphologically similar, muscoides-like Fucus inhabiting salt marshes in Iceland and Ireland. The Icelandic genotypes were consistent with Fucus vesiculosus×Fucus spiralis F1 hybrids with asymmetrical hybridization, whereas the Irish ones consisted primarily of polyploid F. vesiculosus.
