Multi-scale drivers of community diversity and composition across tidal heights: an example on temperate seaweed communities

International audienc

Dinard Herbarium: A Source of Information to Infer Temporal Changes in Seaweed Communities?

International audienc

Data mining approach identifies research priorities and data requirements for resolving the red algal tree of life

<p>Abstract</p> <p>Background</p> <p>The assembly of the tree of life has seen significant progress in recent years but algae and protists have been largely overlooked in this effort. Many groups of algae and protists have ancient roots and it is unclear how much data will be required to resolve their phylogenetic relationships for incorporation in the tree of life. The red algae, a group of primary photosynthetic eukaryotes of more than a billion years old, provide the earliest fossil evidence for eukaryotic multicellularity and sexual reproduction. Despite this evolutionary significance, their phylogenetic relationships are understudied. This study aims to infer a comprehensive red algal tree of life at the family level from a supermatrix containing data mined from GenBank. We aim to locate remaining regions of low support in the topology, evaluate their causes and estimate the amount of data required to resolve them.</p> <p>Results</p> <p>Phylogenetic analysis of a supermatrix of 14 loci and 98 red algal families yielded the most complete red algal tree of life to date. Visualization of statistical support showed the presence of five poorly supported regions. Causes for low support were identified with statistics about the age of the region, data availability and node density, showing that poor support has different origins in different parts of the tree. Parametric simulation experiments yielded optimistic estimates of how much data will be needed to resolve the poorly supported regions (ca. 10³to ca. 10⁴nucleotides for the different regions). Nonparametric simulations gave a markedly more pessimistic image, some regions requiring more than 2.8 10⁵nucleotides or not achieving the desired level of support at all. The discrepancies between parametric and nonparametric simulations are discussed in light of our dataset and known attributes of both approaches.</p> <p>Conclusions</p> <p>Our study takes the red algae one step closer to meaningful inclusion in the tree of life. In addition to the recovery of stable relationships, the recognition of five regions in need of further study is a significant outcome of this work. Based on our analyses of current availability and future requirements of data, we make clear recommendations for forthcoming research.</p

Morphological and molecular assessment of Lithophyllum okamurae with the description of L. neo-okamurae sp. nov. (Corallinales, Rhodophyta)

Lithophyllum okamurae has been widely reported in the Pacific Ocean with identification based on morpho-anatomical observations. Two infraspecific taxa, L. okamurae f. okamurae and f. angulare, described from Japan, have been recorded in the temperate region of Japan. We assessed branched Lithophyllum samples morphologically referable to L. okamurae using morpho-anatomical data and DNA sequences (psbA, rbcL and partial LSU rDNA) obtained from herbarium specimens, including type material, as well as recently field-collected material in Japan. The molecular analyses showed that these ‘L. okamurae’ samples contained two species: L. okamurae and a cryptic new species which we describe as L. neo-okamurae sp. nov. Because the holotype of L. okamurae f. angulare was conspecific with original material cited in the protologue of L. okamurae, it is a heterotypic synonym of L. okamurae f. okamurae. Lithophyllum okamurae and L. neo-okamurae were morphologically similar in having warty, lumpy and fruticose thalli and in often forming rhodoliths. Lithophyllum okamurae can be morpho-anatomically distinguished from L. neo-okamurae by the thallus with tapering or plate-like protuberances (knobby protuberances in the latter) and by having smaller tetrasporangial conceptacle chambers (167–314 μm; 248–380 μm in L. neo-okamurae). Our LSU rDNA sequence data from L. okamurae f. angulare (=L. okamurae f. okamurae) was identical to that of the type of L. margaritae, which has nomenclatural priority over L. okamurae. However, considering that psbA and rbcL sequences of L. margaritae type material could not be generated in the present study, we refrain, for the moment, from proposing the taxonomic synonymy between these two taxa until the status of L. margaritae and its synonyms from the type locality (Gulf of California) are clarified.This research was mainly supported by Japan Society for the Promotion of Science (JSPS KAKENHI Grant Number 26850123, 17K07908) to AK

Molecular phylogenies support taxonomic revision of three species of Laurencia (Rhodomelaceae, Rhodophyta), with the description of a new genus

Systematics of the Laurencia complex was investigated using a taxon-rich data set including the chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) gene only and a character-rich data set combining the mitochondrial cytochrome oxidase 1 (COI-5P), the rbcL marker, and the nuclear large subunit of the ribosomal operon (LSU). Bayesian and ML analyses of these data sets showed that three species hitherto placed in the genus Laurencia were not closely related to Laurencia sensu stricto. Laurencia caspica was the sister group of the remaining Osmundea species, L. crustiformans joined Palisada and L. flexilis consisted of an independent lineage. In light of these results a new genus, Ohelopapa, was proposed to accommodate L. flexilis. This new genus is morphologically characterized by four pericentral cells in each vegetative axial segment, however it lacks corps en cerise in cortical cells and secondary pit connections between cortical cells which are characteristic in Laurencia. Three novel combinations are proposed to render the classification closer to a natural system: Ohelopapa flexilis, Osmundea caspica, and Palisada crustiformans

DNA-barcoding revela la existencia de un posible nuevo género del complejo Laurencia (Rodophyta, Ceramiales) en las islas Canarias

XIX Simposio de Botánica Criptogámica, Las Palmas de Gran Canaria, 24-28 de junio de 2013.Basado en análisis morfológicos y moleculares, en la actualidad el complejo Laurencia (Rhodophyta, Ceramiales) incluye seis géneros (Chondrophycus, Laurencia, Laurenciella, Osmundea, Palisada y Yuzurua). El objetivo principal de este estudio preliminar es valorar a nivel molecular la posible existencia de un nuevo género dentro del complejo Laurencia presente en las Islas Canarias, así como establecer posibles relaciones filogenéticas entre éste y otros taxones del complejo citados en la Macaronesia

A molecular perspective of the Laurencia complex (Ceramiales, Rhodophyta) in Macaronesia region

IV Congress of Marine Sciences. Las Palmas de Gran Canaria, June 11th to 13th 2014.In the present study, we undertook an integrative approach, using molecular data to assess the diversity of the Laurencia complex in Macaronesian islands (Azores, Madeira and Canary Islands) where speciation events are supposedly common leading to a high endemism. Identification of species of the Laurencia complex based on anatomical and morphological characters is extremely difficult due to phenotypic plasticity and overlaps in many morphological characters. As a consequence, among the 28 species reported so far from these Macaronesian archipelagos, 14 species records have been regarded as doubtful. We used DNA barcode data (mitochondrial COI gene and partial nuclear LSU marker) as a tool for species delimitation. A third marker (rbcL gene) was also studied and phylogenetic analyses were carried out using the three independent markers as well as the combined data set, in the aim to infer the phylogenetic relationships and biogeographic affinities of members of the complex from Macaronesia. Our results proved the usefulness of the DNA barcode markers for uncovering several putative new species of the Laurencia complex in Macaronesia and phylogenetic results revealed the existence of a potential new genus present in Canary Islands, which adds to the six pre-existing genera: Laurencia, Osmundea, Chondrophycus, Palisada, Yuzurua and Laurenciella

Saffron extract (Safr’InsideTM) improves anxiety related behaviour in a mouse model of low-grade inflammation through the modulation of the microbiota and gut derived metabolites

Treatment of anxiety and depression predominantly centres around pharmacological interventions, which have faced criticism for their associated side effects, lack of efficacy and low tolerability. Saffron, which is reportedly well tolerated in humans, has been recognised for its antidepressant and anti-anxiety properties. Indeed, we previously reported upon the efficacy of saffron extract supplementation in healthy adults with subclinical anxiety. However, the molecular aetiology remains unclear. In a rodent model of low-grade chronic inflammation, we explored the impact of a saffron extract (Safr’InsideTM) supplementated at a physiological dose, which equated to 22 ± 1.2 mg per day human equivalent dose for a person of 60 Kg. Behavioural tests (Open field task, Y maze, Novel object recognition), caecal 16S rRNA microbial sequencing, caecal 1H NMR metabolomic analysis and 2DE brain proteomic analyses were completed to probe gut-brain axis interactions. Time occupying the centre of the Open field maze (OF) was increased by 62% in saffron supplemented animals. This improvement in anxiety-related behaviour coincided with gut microbial shifts, notably Akkermansia, Muribaculaceae, Christensenellacae and Alloprevotella which significantly increased in response to saffron supplementation. Akkermansia and Muribaculaceae abundance negatively correlated with the neurotoxic metabolite dimethylamine which was reduced in saffron supplemented animals. Brain proteomic analysis highlighted several significantly altered proteins including ketimine reductase mu-crystallin which also correlated with dimethylamine concentration. Both dimethylamine and ketimine reductase mu-crystallin were associated with OF performance. This may be indicative of a novel interaction across the gut-brain axis which contributes to anxiety-related disorders

Flora coralinal no geniculada de la región macaronésica: evidencias moleculares de su singularidad y relaciones biogeográficas con la flora europea

XIX Simposio de Botánica Criptogámica, Las Palmas de Gran Canaria, 24-28 de junio de 2013.Después de las primeras contribuciones a la flora coralinal de la región macaronésica por parte de Lamarck (1815), Montagne (1840) y Viera (1868-1869), han sido unos pocos ficólogos los que han aportado nuevas especies para los diferentes archipiélagos que componen esta región (Foslie 1905, 1906, May 1912, Lemoine 1929). Aparte del componente endémico de su flora, otras especies citadas presentan una distribución mucho más amplia. En la flora coralinal de Canarias, Afonso-­Carrillo et al (1984) distinguieron cuatro grupos biogeográficos, dos de los cuales contienen especies citadas en las costas europeas mientras que otros dos corresponden a especies pantropicales y especies cosmopolitas, respectivamente. La contribución de especies europeas y tropicales también se hizo patente en un análisis global de las algas coralinas geniculadas presentes en esta región (Rosas-­Alquicira et al. 2011). Athanasiadis & Neto (2010) citaron Mesophyllum expansum para Azores e Islas Canarias, una especie característica del coralígeno mediterráneo. Los fondos de maërl fueron estudiados por Cabioch (1974) y Afonso-­Carrillo et al. (1982) en Madeira y Canarias. Las algas coralinas no geniculadas presentan una alta plasticidad fenotípica que conlleva tanto una variación extrema dentro de un mismo taxón como convergencias entre taxones filogenéticamente distantes (Steneck 1986) que lo convierte en un grupo taxonómicamente muy complejo. El reciente empleo de la taxonomía molecular en estas algas ha puesto de manifiesto la inestabilidad de ciertos caracteres morfológicos tradicionales y la existencia de especies crípticas (Bailey & Chapman 1998, Harvey et al. 2002, Vidal et al. 2003, Broom et al. 2008, Bittner et al. 2010, Le Gall et al. 2010, Hind & Saunders 2013). Desde 2011, se está llevando a cabo un estudio acerca de la diversidad de las algas coralinas no geniculadas de la costas europeas mediante el empleo de DNA barcoding. Para este proyecto, se han recogido unos 1500 especímenes en 128 localidades de la costas atlántica y mediterránea, desde el intermareal hasta 94 m de profundidad, incluyendo fondos de maërl y coralígeno. Adicionalmente, se han incluido diversas colecciones procedentes de Canarias y Madeira, así como algunos especímenes preservados en el herbario AZB de Azores. En el presente trabajo analizamos las relaciones biogeográficas entre ambas áreas de estudio basados en nuestras secuencias y en las existentes en las bases de datos BOLD y Genbank. Los resultados obtenidos aportan un mayor conocimiento de la flora coralinal macaronésica y sus particularidades florísticas