Molecular phylogeny, phylogeography and population genetics of the red seaweed genus <i>Asparagopsis</i>

The red seaweed genus Asparagopsis Montagne (Bonnemaisoniales) was studied with respect to its taxonomy, phylogeny, phylogeography and population genetics. The representatives of this genus, A. armata Harvey and A. taxiformis (Delile) Trevisan, are notorious invaders. Both species occur worldwide and show disjunct distribution patterns. Such patterns may result from recent jump-dispersal or from fragmentation of once panglobally distributed species. First, a phylogeographic approach was deployed in order to delineate the taxonomic units in local scale and to assess if European populations of each of the species originated from a single introduction or multiple cryptic ones. Results showed that the two species recognized A. armata and A. taxiformis are also genetically distinct. Asparagopsis armata was found to consist of a single species worldwide, whereas A. taxiformis constituted three and probably four morphologically cryptic but genetically distinct lineages. At times, lineages were encountered in sympatry and two of them were detected in the Mediterranean Sea. In order to confirm distinction between lineages and to assess invasive potential and colonization mechanisms of the species along the western Italian coast, eight nuclear micro satellite markers were identified against the invasive lineage 2 of A. taxiformis. The markers cross-hybridised only with lineages I and 2. Moreover, it was demonstrated that carpogonia present on many female thalli can affect microsatellite reading patterns because of external (male) allelic contribution. Even after removal of the carpogonia, gametophyte thalli exhibited multiple allelic patterns, which is indicative for polyploidy. The markers were then used to assess genetic structure and diversity within and among Mediterranean populations of A. taxiformis lineages 1 and 2. Analyses based on statistics developed for polyploid species showed that the lineage l-population (HAW) was distinct from Mediterranean lineage 2 populations. A geographically distant Californian lineage 2· population was genetically distinct from the Mediterranean ones as well. The Mediterranean lineage 2-samples showed panmixia. High genotypic diversity, high gene flow, and low differentiation encountered amongst these populations probably are due to a recent invasion of this lineage into the basin

Molecular phylogeny, phylogeography and population genetics of the red seaweed genus <i>Asparagopsis</i>

The red seaweed genus Asparagopsis Montagne (Bonnemaisoniales) was studied with respect to its taxonomy, phylogeny, phylogeography and population genetics. The representatives of this genus, A. armata Harvey and A. taxiformis (Delile) Trevisan, are notorious invaders. Both species occur worldwide and show disjunct distribution patterns. Such patterns may result from recent jump-dispersal or from fragmentation of once panglobally distributed species. First, a phylogeographic approach was deployed in order to delineate the taxonomic units in local scale and to assess if European populations of each of the species originated from a single introduction or multiple cryptic ones. Results showed that the two species recognized A. armata and A. taxiformis are also genetically distinct. Asparagopsis armata was found to consist of a single species worldwide, whereas A. taxiformis constituted three and probably four morphologically cryptic but genetically distinct lineages. At times, lineages were encountered in sympatry and two of them were detected in the Mediterranean Sea. In order to confirm distinction between lineages and to assess invasive potential and colonization mechanisms of the species along the western Italian coast, eight nuclear micro satellite markers were identified against the invasive lineage 2 of A. taxiformis. The markers cross-hybridised only with lineages I and 2. Moreover, it was demonstrated that carpogonia present on many female thalli can affect microsatellite reading patterns because of external (male) allelic contribution. Even after removal of the carpogonia, gametophyte thalli exhibited multiple allelic patterns, which is indicative for polyploidy. The markers were then used to assess genetic structure and diversity within and among Mediterranean populations of A. taxiformis lineages 1 and 2. Analyses based on statistics developed for polyploid species showed that the lineage l-population (HAW) was distinct from Mediterranean lineage 2 populations. A geographically distant Californian lineage 2· population was genetically distinct from the Mediterranean ones as well. The Mediterranean lineage 2-samples showed panmixia. High genotypic diversity, high gene flow, and low differentiation encountered amongst these populations probably are due to a recent invasion of this lineage into the basin

Dietary supplementation of astaxanthin modulates skin color and liver antioxidant status of giant grouper (Epinephelus lanceolatus)

Giant grouper (Epinephelus lanceolatus) is an emerging aquaculture species in Southeast Asia and Australia with limited knowledge of its nutrient requirements and effects of supplements on its physiology. The present study investigated the effects of astaxanthin, vitamin E, and combinations on growth performance, body coloration, and the antioxidant status of juvenile giant grouper. Nine isonitrogenous (crude protein = 65 % ± 0.7 %) and isolipidic (crude lipid = 10 % ± 0.3 %) diets were formulated using a 3 × 3 factorial design, including three levels astaxanthin (0, 75, and 150 mg/kg) and vitamin E (0, 250, and 500 mg/kg), respectively. Each of the nine diets was fed to triplicate groups of 15 giant grouper (18.04 ± 0.92 g) for 30 days. Giant grouper fed the different diets exhibited no significant differences (p > 0.05) in specific growth rate (4.87 %/day - 5.21 %/day). However, dietary astaxanthin supplementation significantly enhanced the redness (a*), yellowness (b*b*), chroma, and hue values of the fin, regardless of the dose supplemented. Giant grouper fed astaxanthin at 75 and 150 mg/kg diet were more yellow and had three times higher b* values than fish fed non-supplemented diets. Further, total antioxidant capacity (TAC; mmol Trolox equivalent) in liver tissues was significantly increased in fish fed any of the astaxanthin-supplemented diets (p ≤ 0.05). In contrast, TAC levels were not affected by vitamin E supple-mentation. Malondialdehyde (MDA) levels were not significantly (p > 0.05) affected by astaxanthin or vitamin E. Findings from this study will contribute toward a better understanding of the dietary effects of antioxidant and pigment in juvenile giant grouper. We present that dietary treatment can modulate giant grouper pigmentation and may be used in the live fish trade. Further, this study contributes to narrowing the knowledge gap in formulating appropriate diets for giant grouper, which to date is fed diets formulated for other species

Primera cita de Caulerpa cylindracea (Caulerpaceae, Chlorophyta) en Andalucía (Sur de España)

Three different species of Caulerpa (Caulerpaceae, Chlorophyta) co-occur in the Mediterranean Sea: two of them are found at the central-eastern basin and are typically considered non aggressive components of the Lessepsian flora [(C. chemnitzia(Esper) J.V. Lamouroux and C. racemosa var. lamourouxii (Turner) Weber-van Bosse f. requienii(Montagne) Weber van Bosse)]; a third taxon, C. cylindracea Sonder has aggressively expanded its range since its first observation in 1990, and it is nowadays reported from nearly all the Mediterranean countries. We report a population of C. cylindracea from Almería (Andalusia, Southern Iberian Peninsula) at −30 m depth as to be the westernmost record of the invasive variety on the Mediterranean European coast. Therefore, we made use of morphological description and molecular phylogenetics to provide a complete identification of this invasive seaweed in Southern Spain. Our findings are discussed in light of the composition of the receptor communities, such as maërl bed, edges of Posidonia oceanica (Linnaeus) Delile, and their ecology. Our results confirmed the suggested directionality of the invasive pathway to be westward to the Strait of Gibraltar, mainly supported by sea currents and vectors of anthropogenic origin.En el Mar Mediterráneo se encuentran tres especies diferentes de Caulerpa (Caulerpaceae, Chlorophyta): dos de ellas se localizan en la cuenca centro oriental y se consideran componentes no agresivos de la flora Lessepsiana (C. chemnitzia (Esper) J.V. Lamouroux and C. racemosa var. lamourouxii (Turner) Weber-van Bosse f. requienii (Montagne) Weber van Bosse); un tercer taxon, C. cylindracea Sonder ha expandido de manera agresiva su rango de distribución desde su primera observación en 1990, y actualmente se registra en casi todos los países de la cuenca mediterránea. En este trabajo se informa sobre una población de C. cylindracea en Almería (Andalucía, Sur de España), a −30 m de profundidad, que representaría la cita más occidental de la variedad invasora en las costas mediterráneas europeas. Se realiza una completa identificación de esta alga invasora en el Sur de España mediante una descripción morfológica y filogenia molecular. Los datos obtenidos se discuten en relación a la composición de las comunidades receptoras, tales como fondos de maërl y bordes de Posidonia oceanica (Linnaeus) Delile, y su ecología. Los resultados confirman la direccionalidad de la ruta invasora de la especie hacia el oeste en las proximidades del Estrecho de Gibraltar, principalmente debido a corrientes marinas y vectores de origen antropogénico.This work has been founded by the projects CGL2008/01549/BOS and CGL2008/02298/BOS (Ministerio de Ciencia e Innovación), P09-RNM-5187 (Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía), 806/5.03.3553 and 806/5.03.3673 (Instituto de Estudios Ceutíes), and has been developed in the framework of the Research Collaboration Agreement between Consejería de Medio Ambiente de la Junta de Andalucía and the University of Málaga

Using bacterial extract along with differential gene expression in Acropora millepora Larvae to decouple the processes of attachment and metamorphosis

Biofilms of the bacterium Pseudoalteromonas induce metamorphosis of acroporid coral larvae. The bacterial metabolite tetrabromopyrrole (TBP), isolated from an extract of Pseudoalteromonas sp. associated with the crustose coralline alga (CCA) Neogoniolithon fosliei, induced coral larval metamorphosis (100%) with little or no attachment (0-2%). To better understand the molecular events and mechanisms underpinning the induction of Acropora millepora larval metamorphosis, including cell proliferation, apoptosis, differentiation, migration, adhesion and biomineralisation, two novel coral gene expression assays were implemented. These involved the use of reverse-transcriptase quantitative PCR (RT-qPCR) and employed 47 genes of interest (GOI), selected based on putative roles in the processes of settlement and metamorphosis. Substantial differences in transcriptomic responses of GOI were detected following incubation of A. millepora larvae with a threshold concentration and 10-fold elevated concentration of TBP-containing extracts of Pseudoalteromonas sp. The notable and relatively abrupt changes of the larval body structure during metamorphosis correlated, at the molecular level, with significant differences (p<0.05) in gene expression profiles of 24 GOI, 12 hours post exposure. Fourteen of those GOI also presented differences in expression (p<0.05) following exposure to the threshold concentration of bacterial TBP-containing extract. The specificity of the bacterial TBP-containing extract to induce the metamorphic stage in A. millepora larvae without attachment, using a robust, low cost, accurate, ecologically relevant and highly reproducible RT-qPCR assay, allowed partially decoupling of the transcriptomic processes of attachment and metamorphosis. The bacterial TBP-containing extract provided a unique opportunity to monitor the regulation of genes exclusively involved in the process of metamorphosis, contrasting previous gene expression studies that utilized cues, such as crustose coralline algae, biofilms or with GLW-amide neuropeptides that stimulate the entire onset of larval metamorphosis and attachment. © 2012 Siboni et al

Differential regulation of the zebrafish orthopedia1 gene during fate determination of diencephalic neurons

BACKGROUND: The homeodomain transcription factor Orthopedia (Otp) is essential in restricting the fate of multiple classes of secreting neurons in the neuroendocrine hypothalamus of vertebrates. However, there is little information on the intercellular factors that regulate Otp expression during development. RESULTS: Here, we identified two otp orthologues in zebrafish (otp1 and otp2) and explored otp1 in the context of the morphogenetic pathways that specify neuroectodermal regions. During forebrain development, otp1 is expressed in anterior groups of diencephalic cells, positioned in the preoptic area (PO) (anterior alar plate) and the posterior tuberculum (PT) (posterior basal plate). The latter structure is characterized by Tyrosine Hydroxylase (TH)-positive cells, suggesting a role for otp1 in the lineage restriction of catecholaminergic (CA) neurons. Disruptions of Hedgehog (HH) and Fibroblast Growth Factor (FGF) pathways point to the ability of SHH protein to trigger otp1 expression in PO presumptive neuroblasts, with the attenuating effect of Dzip1 and FGF8. In addition, our data disclose otp1 as a determinant of CA neurons in the PT, where otp1 activity is strictly dependent on Nodal signaling and it is not responsive to SHH and FGF. CONCLUSION: In this study, we pinpoint the evolutionary importance of otp1 transcription factor in cell states of the diencephalon anlage and early neuronal progenitors. Furthermore, our data indicate that morphogenetic mechanisms differentially regulate otp1 expression in alar and basal plates

Host and Environmental Specificity in Bacterial Communities Associated to Two Highly Invasive Marine Species (Genus Asparagopsis)

As habitats change due to global and local pressures, population resilience, and adaptive processes depend not only on their gene pools but also on their associated bacteria communities. The hologenome can play a determinant role in adaptive evolution of higher organisms that rely on their bacterial associates for vital processes. In this study, we focus on the associated bacteria of the two most invasive seaweeds in southwest Iberia (coastal mainland) and nearby offshore Atlantic islands, Asparagopsis taxiformis and Asparagopsis armata. Bacterial communities were characterized using 16S rRNA barcoding through 454 next generation sequencing and exploratory shotgun metagenomics to provide functional insights and a backbone for future functional studies. The bacterial community composition was clearly different between the two species A. taxiformis and A. armata and between continental and island habitats. The latter was mainly due to higher abundances of Acidimicrobiales, Sphingomonadales, Xanthomonadales, Myxococcales, and Alteromonadales on the continent. Metabolic assignments for these groups contained a higher number of reads in functions related to oxidative stress and resistance to toxic compounds, more precisely heavy metals. These results are in agreement with their usual association with hydrocarbon degradation and heavy-metals detoxification. In contrast, A. taxiformis from islands contained more bacteria related to oligotrophic environments which might putatively play a role in mineralization of dissolved organic matter. The higher number of functional assignments found in the metagenomes of A. taxiformis collected from Cape Verde Islands suggest a higher contribution of bacteria to compensate nutrient limitation in oligotrophic environments. Our results show that Asparagopsis-associated bacterial communities have host-specificity and are modulated by environmental conditions. Whether this environmental effect reflects the host's selective requirements or the locally available bacteria remains to be addressed. However, the known functional capacities of these bacterial communities indicate their potential for eco-physiological functions that could be valuable for the host fitness

Recombinant interleukin-1β dilates steelhead trout coronary microvessels : effect of temperature and role of the endothelium, nitric oxide and prostaglandins

© 2015. Published by The Company of Biologists Ltd. Acknowledgements We thank Wenjuan Xu and Xin Xu (Hein Lab) for their excellent instruction in microvessel techniques, Dr David Heeley (Biochemistry Department, MUN) for assistance with selecting an appropriate (non-vasoactive) protein stabilizer, Dr Zou (SFIRC, Aberdeen) for advice with regards to the use of rIL-1β and Gordon Nash (Gamperl Lab) for his assistance with the rIL-1β purification protocol. Funding This research was supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant [RGPIN249926] and Accelerator Supplement [RGPAS412325-2011] to A.K.G. a National Institutes of Health Grant [EY018420] to T.W.H., and a doctoral fellowship from Fundaçã o para a Ciência e a Tecnologia, Portugal [SFRH/BD/27497/2006] to I.A.S.F.C. Deposited in PMC for release after 12 months.Peer reviewedPublisher PD

The Mediterranean Red Alga Asparagopsis: A Source of Compounds against Leishmania

Crude extracts and column fractions from the red algae Asparagopsis taxiformis and A. armata from the Strait of Messina (Italy) were screened for the production of antimicrobial compounds. Extracts from both species revealed remarkable antiprotozoal activity against Leishmania, revealing such algae as a great source of natural antiprotozoal products

Nuclear DNA content variation in life history phases of the Bonnemaisoniaceae (Rhodophyta)

Nuclear DNA content in gametophytes and sporophytes or the prostrate phases of the following species of Bonnemaisoniaceae (Asparagopsis armata, Asparagopsis taxiformis, Bonnemaisonia asparagoides, Bonnemaisonia clavata and Bonnemaisonia hamifera) were estimated by image analysis and static microspectrophotometry using the DNA-localizing fluorochrome DAPI (4′, 6-diamidino-2-phenylindole, dilactate) and the chicken erythrocytes standard. These estimates expand on the Kew database of DNA nuclear content. DNA content values for 1C nuclei in the gametophytes (spermatia and vegetative cells) range from 0.5 pg to 0.8 pg, and for 2C nuclei in the sporophytes or the prostrate phases range from 1.15-1.7 pg. Although only the 2C and 4C values were observed in the sporophyte or the prostrate phase, in the vegetative cells of the gametophyte the values oscillated from 1C to 4C, showing the possible start of endopolyploidy. The results confirm the alternation of nuclear phases in these Bonnemaisoniaceae species, in those that have tetrasporogenesis, as well as those that have somatic meiosis. The availability of a consensus phylogenetic tree for Bonnemaisoniaceae has opened the way to determine evolutionary trends in DNA contents. Both the estimated genome sizes and the published chromosome numbers for Bonnemaisoniaceae suggest a narrow range of values consistent with the conservation of an ancestral genome