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1.
Nat Commun ; 12(1): 6651, 2021 11 17.
Artículo en Inglés | MEDLINE | ID: mdl-34789758

RESUMEN

The endosymbiotic origin of plastids from cyanobacteria gave eukaryotes photosynthetic capabilities and launched the diversification of countless forms of algae. These primary plastids are found in members of the eukaryotic supergroup Archaeplastida. All known archaeplastids still retain some form of primary plastids, which are widely assumed to have a single origin. Here, we use single-cell genomics from natural samples combined with phylogenomics to infer the evolutionary origin of the phylum Picozoa, a globally distributed but seemingly rare group of marine microbial heterotrophic eukaryotes. Strikingly, the analysis of 43 single-cell genomes shows that Picozoa belong to Archaeplastida, specifically related to red algae and the phagotrophic rhodelphids. These picozoan genomes support the hypothesis that Picozoa lack a plastid, and further reveal no evidence of an early cryptic endosymbiosis with cyanobacteria. These findings change our understanding of plastid evolution as they either represent the first complete plastid loss in a free-living taxon, or indicate that red algae and rhodelphids obtained their plastids independently of other archaeplastids.


Asunto(s)
Eucariontes/genética , Plastidios/genética , Rhodophyta/genética , Evolución Biológica , Eucariontes/clasificación , Variación Genética , Genoma/genética , Genómica , Filogenia , Rhodophyta/clasificación , Análisis de la Célula Individual
2.
Genes (Basel) ; 12(7)2021 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-34356071

RESUMEN

Red algae (Rhodophyta) belong to the superphylum Archaeplastida, and are a species-rich group exhibiting diverse morphologies. Theory has it that the unicellular red algal ancestor went through a phase of genome contraction caused by adaptation to extreme environments. More recently, the classes Porphyridiophyceae, Bangiophyceae, and Florideophyceae experienced genome expansions, coinciding with an increase in morphological complexity. Transcription-associated proteins (TAPs) regulate transcription, show lineage-specific patterns, and are related to organismal complexity. To better understand red algal TAP complexity and evolution, we investigated the TAP family complement of uni- and multi-cellular red algae. We found that the TAP family complement correlates with gain of morphological complexity in the multicellular Bangiophyceae and Florideophyceae, and that abundance of the C2H2 zinc finger transcription factor family may be associated with the acquisition of morphological complexity. An expansion of heat shock transcription factors (HSF) occurred within the unicellular Cyanidiales, potentially as an adaption to extreme environmental conditions.


Asunto(s)
Evolución Molecular , Variación Genética , Genoma , Filogenia , Rhodophyta/clasificación , Rhodophyta/genética , Factores de Transcripción/metabolismo , Rhodophyta/química , Rhodophyta/metabolismo , Factores de Transcripción/genética
3.
Methods Mol Biol ; 2290: 31-51, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34009581

RESUMEN

Worldwide demand for ethanol alternative fuel has been emerging day by day owing to the rapid population growth and industrialization. Culturing microalgae as an alternative feedstock is anticipated to be a potentially significant approach for sustainable bioethanol biofuel production. Microalgae are abundant in nature, which grow at faster rates with a capability of storing high lipid and starch/cellulose contents inside their cells. This process offers several environmental advantages, including the effective utilization of land, good CO2 sequestration without entering into "food against fuel" dispute. This chapter focuses on the methods and processes used for the production of bioethanol biofuels from algae. Thus, it also covers significant achievements in the research and developments on algae bioethanol production, mainly including pretreatment, hydrolysis, and fermentation of algae biomass. The processes of producing biodiesel, biogas, and hydrogen have also been discussed.


Asunto(s)
Biocombustibles , Biotecnología/métodos , Etanol/metabolismo , Microalgas , Biomasa , Fermentación , Rayos gamma , Hidrógeno/metabolismo , Microalgas/crecimiento & desarrollo , Microalgas/metabolismo , Microondas , Phaeophyceae/clasificación , Phaeophyceae/metabolismo , Fitoplancton , Rhodophyta/clasificación , Rhodophyta/metabolismo , Ultrasonido
4.
Int J Biol Macromol ; 164: 4381-4390, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32926901

RESUMEN

Many marine polysaccharides as prebiotics can promote host health by modulating gut microbiota. This study investigated the beneficial effects of purified marine plant-derived Gelidium pacificum Okamura polysaccharide (GPOP-1) and marine animal-derived Cereus sinensis polysaccharide (CSP-1) on normal mice by modulating gut microbiota. The composition and diversity of gut microbiota were evaluated using 16S rRNA high-throughput sequencing. The results showed that GPOP-1 and CSP-1 altered the composition of the gut microbiota and promoted the growth of beneficial bacteria. At the genus level, GPOP-1 increased the relative abundance of Bacteroides, Phascolarctobacterium, and decreased the relative abundance of Ruminococcus, Helicobacter, Allobaculum, Dorea and AF12. While CSP-1 increased the relative abundance of Coprococcus, Adlercreutzia, Roseburia, Phascolarctobacterium, and decreased the relative abundance of Bacteroides, Ruminococcus and Oscillospira. The changes in the gut microbiota may affect the body weight, immune organ index and the production of short-chain fatty acids in normal mice. Compared to the normal control group, GPOP-1 decreased average weight gain while CSP-1 increased average weight gain. Furthermore, both GPOP-1 and CSP-1 significantly increased thymus and spleen indexes and total short chain fatty acids production in mice. In summary, GPOP-1 and CSP-1 exerted prebiotic effects on normal mice.


Asunto(s)
Organismos Acuáticos/química , Polisacáridos/química , Polisacáridos/farmacología , Prebióticos , Rhodophyta/química , Animales , Organismos Acuáticos/genética , Biodiversidad , Peso Corporal/efectos de los fármacos , Ácidos Grasos Volátiles/química , Ácidos Grasos Volátiles/metabolismo , Microbioma Gastrointestinal , Ratones , Tamaño de los Órganos/efectos de los fármacos , Rhodophyta/clasificación , Rhodophyta/genética
5.
Sci Rep ; 10(1): 13794, 2020 08 24.
Artículo en Inglés | MEDLINE | ID: mdl-32839467

RESUMEN

Microalgae possess high potential for producing pigments, antioxidants, and lipophilic compounds for industrial applications. However, their open pond cultures are often contaminated by other undesirable organisms, including their predators. In addition, the cost of using freshwater is relatively high, which limits the location and scale of cultivation compared with using seawater. It was previously shown that Cyanidium caldarium and Galdieria sulphuraria, but not Cyanidioschyzon merolae grew in media containing NaCl at a concentration equivalent to seawater. We found that the preculture of C. merolae in the presence of a moderate NaCl concentration enabled the cells to grow in the seawater-based medium. The cultivation of cyanidialean red algae in the seawater-based medium did not require additional pH buffering chemicals. In addition, the combination of seawater and acidic conditions reduced the risk of contamination by other organisms in the nonsterile open culture of C. merolae more efficiently than the acidic condition alone.


Asunto(s)
Ácidos/química , Medios de Cultivo/química , Microalgas/crecimiento & desarrollo , Rhodophyta/crecimiento & desarrollo , Agua de Mar/química , Medios de Cultivo/farmacología , Concentración de Iones de Hidrógeno , Microalgas/clasificación , Microalgas/efectos de los fármacos , Técnicas Microbiológicas/métodos , Reproducibilidad de los Resultados , Rhodophyta/clasificación , Rhodophyta/efectos de los fármacos
6.
PLoS One ; 15(7): e0234358, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32634147

RESUMEN

Survey cruises by the National Oceanic and Atmospheric Administration (NOAA) in 2016 and 2019 yielded specimens of an undetermined red alga that rapidly attained alarming levels of benthic coverage at Pearl and Hermes Atoll, Papahanaumokuakea Marine National Monument, Hawai'i. By 2019 the seaweed had covered large expanses on the northeast side of the atoll with mat-like, extensive growth of entangled thalli. Specimens were analyzed using light microscopy and molecular analysis, and were compared to morphological descriptions in the literature for closely related taxa. Light microscopy demonstrated that the specimens likely belonged to the rhodomelacean genus Chondria, yet comparisons to taxonomic literature revealed no morphological match. DNA sequence analyses of the mitochondrial COI barcode marker, the plastidial rbcL gene, and the nuclear SSU gene confirmed its genus-level placement and demonstrated that this alga was unique compared to all other available sequences. Based on these data, this cryptogenic seaweed is here proposed as a new species: Chondria tumulosa A.R.Sherwood & J.M.Huisman sp. nov. Chondria tumulosa is distinct from all other species of Chondria based on its large, robust thalli, a mat-forming tendency, large axial diameter in mature branches (which decreases in diameter with subsequent orders of branching), terete axes, and bluntly rounded apices. Although C. tumulosa does not meet the criteria for the definition of an invasive species given that it has not been confirmed as introduced to Pearl and Hermes Atoll, this seaweed is not closely related to any known Hawaiian native species and is of particular concern given its sudden appearance and rapid increase in abundance in the Papahanaumokuakea Marine National Monument; an uninhabited, remote, and pristine island chain to the northwest of the Main Hawaiian Islands.


Asunto(s)
Rhodophyta/clasificación , Rhodophyta/genética , Clasificación/métodos , Hawaii , Especies Introducidas , Islas , Filogenia , Algas Marinas , Análisis de Secuencia de ADN/métodos
7.
Molecules ; 25(14)2020 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-32709154

RESUMEN

This study presents a chemotaxonomic investigation of the genus Bostrychia through the quantitation of the major mycosporine-like amino acids (MAAs). The presence of some cryptic species had been suggested in the B. moritziana/B. radicans complex and MAA-profiling in respective samples revealed different chemotypes within this species complex. Another possibly polyphyletic species is Bostrychia simpliciuscula; previous molecular phylogenetic analyses showed four genetic lineages within this species, one of which was recently distinguished as a new species. Phytochemical profiling of those samples used for DNA analyses revealed four different chemotypes, corresponding to the above four lineages and it supports the re-circumscription of the other three B. simpliciuscula lineages. Therefore, mycosporine-like amino acids are considered as suitable chemotaxonomic markers for the reassessment of the classification of B. simpliciuscula. The determination of the MAA patterns in these algae was possible after developing and validating a suitable high-performance liquid chromatography-diode array detector (HPLC-DAD) method.


Asunto(s)
Aminoácidos/química , Filogenia , Rhodophyta/química , Animales , Cromatografía Líquida de Alta Presión , Rhodophyta/clasificación
8.
Mol Phylogenet Evol ; 152: 106909, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32702527

RESUMEN

Our knowledge of seaweed diversity and biogeography still largely relies on information derived from morphological identifications, but the use of molecular tools is revealing that cryptic diversity is common among algae. Polysiphonia scopulorum is a turf-forming red alga widely reported in tropical and temperate coasts worldwide. The only study based on material collected from its Australian type locality and the Iberian Peninsula indicates that it is a species complex, but the extent of cryptic diversity across its geographical range is not known. To investigate the species diversity in P. scopulorum, the geographical distribution of species-level lineages and their morphological characterization, we collected 135 specimens from Australia, South Africa and southern Europe. Two gene datasets (cox1 and rbcL) were used to delimit species using three methods (GMYC, PTP, ABGD), leading to a consensus result that our collections of the P. scopulorum complex comprise 12 species. Five of these species were resolved in a highly supported clade, while the other seven species were related to other taxonomically accepted species or in unresolved parts of the tree. Morphometric and statistical analysis of a set of ten quantitative characters showed that there are no clear morphological correlates of species boundaries, demonstrating true cryptic diversity in the P. scopulorum complex. Distribution patterns of the 12 species were variable, ranging from species only known from a single site to species with a wide distribution spanning three continents. Our study indicates that a significant level of undiscovered cryptic diversity is likely to be found in algal turfs, a type of seaweed community formed by small entangled species.


Asunto(s)
Variación Genética , Filogenia , Rhodophyta/clasificación , Australia , Europa (Continente) , Especiación Genética , Geografía , Rhodophyta/anatomía & histología , Rhodophyta/genética , Sudáfrica
9.
Mol Phylogenet Evol ; 150: 106845, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32360706

RESUMEN

The subclass Corallinophycidae is the only group of red algae characterized by the presence of calcite crystals in their cell walls. Except for the Rhodogorgonales, the remaining orders - collectively called corallines - are diverse and widely distributed, having calcified cell walls and highly variable morphology. Corallines constitute the group with the richest fossil record among marine algae. In the present study, we investigate the evolutionary history of the subclass Corallinophycidae and provide a time-calibrated phylogeny to date the radiation of the crown group and its main lineages. We use a multi-locus dataset with an extensive taxon sampling and comprehensive collection of fossil records, carefully assigned to corallines, to reconstruct a time-calibrated phylogeny of this subclass. Our molecular clock analyses suggest that the onset of crown group diversification of Corallinophycidae started in the Lower Jurassic and sped up in the Lower Cretaceous. The divergence time of the oldest order Sporolithales is estimated in the Lower Cretaceous followed by the remaining orders. We discuss the long period of more than 300 million years between the early Paleozoic records attributed to the stem group of Corallinophycidae and the radiation of the crown group. Our inferred phylogeny yields three highly-supported suprageneric lineages for the order Corallinales; we confirm the family Mastophoraceae and amend circumscription of the families Corallinaceae and Lithophyllaceae. These three families are distinguished by a combination of vegetative and reproductive features. In light of the phylogeny, we discuss the evolutionary trends of eleven morphological characters. In addition, we also highlight homoplasious characters and selected autapomorphies emerging in particular taxa.


Asunto(s)
Rhodophyta/clasificación , Teorema de Bayes , Evolución Biológica , Pared Celular/química , ADN de Plantas/química , ADN de Plantas/metabolismo , Fósiles , Ligamiento Genético , Filogenia , Rhodophyta/genética
10.
Mar Environ Res ; 157: 104930, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32275512

RESUMEN

The distribution of macroalgal species along the north and northwest coast of the Iberian Peninsula is in a period of change, during which mostly cold-temperate species have decreased in cover and others have disappeared. On the other hand, other species have increased in abundance. These shifts could be related with the modification of environmental factors that determine species distribution caused by climate change. A standardised sampling methodology was applied at 18 sites along the north coast of Spain in 2011 and 2017. The relationship between the coverage of intertidal macroalgal species and abiotic variables (sea surface temperature, air temperature and significant wave height) was analysed in order to detect possible changes in the historical data. Results suggest a modification in the communities in the inner part of the Bay of Biscay, mostly related to an increase in water and air temperature. Each seaweed group (warm-temperate, cold-temperate, opportunistic and exotic species) showed a different pattern of modification. Coralline algae, Bifurcaria bifurcata and Cystoseira baccata have increased, which may be related to the warming trend. The exotic species Asparagopsis armata has also increased, particularly in the Lower Rias. On the other hand, there was a drastic decrease of the cold-temperate species Himanthalia elongata. Data obtained support the relationship of macroalgae species communities and environment in the context of climate change in this particular area.


Asunto(s)
Cambio Climático , Phaeophyceae/clasificación , Rhodophyta/clasificación , Algas Marinas/clasificación , España
11.
Metallomics ; 12(4): 617-630, 2020 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-32195517

RESUMEN

Metal transport processes are relatively poorly understood in algae in comparison to higher plants and other eukaryotes. A screen of genomes from 33 taxonomically diverse algal species was conducted to identify members of the Cation Diffusion Facilitator (CDF) family of metal ion transporter. All algal genomes contained at least one CDF gene with four species having >10 CDF genes (median of 5 genes per genome), further confirming that this is a ubiquitous gene family. Phylogenetic analysis suggested a CDF gene organisation of five groups, which includes Zn-CDF, Fe/Zn-CDF and Mn-CDF groups, consistent with previous phylogenetic analyses, and two functionally undefined groups. One of these undefined groups was algal specific although excluded chlorophyte and rhodophyte sequences. The majority of sequences (22 out of 26 sequences) from this group had a putative ion binding site motif within transmembrane domain 2 and 5 that was distinct from other CDF proteins, such that alanine or serine replaced the conserved histidine residue. The phylogenetic grouping was supported by sequence cluster analysis. Yeast heterologous expression of CDF proteins from Chlamydomonas reinhardtii indicated Zn2+ and Co2+ transport function by CrMTP1, and Mn2+ transport function by CrMTP2, CrMTP3 and CrMTP4, which validated the phylogenetic prediction. However, the Mn-CDF protein CrMTP3 was also able to provide zinc and cobalt tolerance to the Zn- and Co-sensitive zrc1 cot1 yeast strain. There is wide diversity of CDF transporters within the algae lineage, and some of these genes may be attractive targets for future applications of metal content engineering in plants or microorganisms.


Asunto(s)
Proteínas de Transporte de Catión/genética , Cobalto/metabolismo , Genómica/métodos , Hierro/metabolismo , Manganeso/metabolismo , Zinc/metabolismo , Secuencia de Aminoácidos , Proteínas de Transporte de Catión/clasificación , Proteínas de Transporte de Catión/metabolismo , Carofíceas/clasificación , Carofíceas/genética , Carofíceas/metabolismo , Chlorophyta/clasificación , Chlorophyta/genética , Chlorophyta/metabolismo , Diatomeas/clasificación , Diatomeas/genética , Diatomeas/metabolismo , Haptophyta/clasificación , Haptophyta/genética , Haptophyta/metabolismo , Transporte Iónico , Filogenia , Rhodophyta/clasificación , Rhodophyta/genética , Rhodophyta/metabolismo , Homología de Secuencia de Aminoácido , Especificidad de la Especie
12.
J Agric Food Chem ; 68(5): 1354-1363, 2020 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-31933364

RESUMEN

Carotenoids are essential phytonutrients synthesized by all photosynthetic organisms. Acyclic lycopene is the first branching point for carotenoid biosynthesis. Lycopene ß- and ε-cyclases (LCYB and LCYE, respectively) catalyze the cyclization of its open ends and direct the metabolic flux into different downstream branches. Carotenoids of the ß,ß-branch (e.g., ß-carotene) are found in all photosynthetic organisms, but those of the ß,ε-branch (e.g., lutein) are generally absent in cyanobacteria, heterokonts, and some red algae. Although both LCYBs and LCYEs have been characterized from land plants, there are only a few reports on LCYs from cyanobacteria and algae. Here, we cloned four LCY genes from Porphyra umbilicalis and Pyropia yezoensis (susabi-nori) of Bangiales, the most primitive red algal order that synthesizes lutein. Our functional characterization in both Escherichia coli and Arabidopsis thaliana demonstrated that each species has a pair of LCYB and LCYE. Similar to LCYs from higher plants, red algal LCYBs cyclize both ends of lycopene, and their LCYEs only cyclize a single end. The characterization of LCYEs from red algae resolved the first bifurcation step toward ß-carotene and lutein biosynthesis. Our phylogenetic analysis suggests that LCYEs of the green lineage and the red algae originated separately during evolution.


Asunto(s)
Liasas Intramoleculares/metabolismo , Luteína/metabolismo , Proteínas de Plantas/metabolismo , Rhodophyta/enzimología , Algas Marinas/enzimología , Secuencia de Aminoácidos , Liasas Intramoleculares/química , Liasas Intramoleculares/genética , Luteína/química , Licopeno/química , Licopeno/metabolismo , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Rhodophyta/clasificación , Rhodophyta/genética , Rhodophyta/metabolismo , Algas Marinas/clasificación , Algas Marinas/genética , Algas Marinas/metabolismo , Alineación de Secuencia
13.
Mol Ecol Resour ; 20(1): 216-227, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31600851

RESUMEN

Pyropia haitanensis (Bangiales, Rhodophyta), a major economically important marine crop, is also considered as an ideal research model of Rhodophyta to address several major biological questions such as sexual reproduction and adaptation to intertidal abiotic stresses. However, comparative genomic analysis to decipher the underlying molecular mechanisms is hindered by the lack of high-quality genome information. Therefore, we integrated sequencing data from Illumina short-read sequencing, PacBio single-molecule sequencing and BioNano optical genome mapping. The assembled genome was approximately 53.3 Mb with an average GC% of 67.9%. The contig N50 and scaffold N50 were 510.3 kb and 5.8 Mb, respectively. Additionally, 10 superscaffolds representing 80.9% of the total assembly (42.7 Mb) were anchored and orientated to the 5 linkage groups based on markers and genetic distance; this outcome is consistent with the karyotype of five chromosomes (n = 5) based on cytological observation in P. haitanensis. Approximately 9.6% and 14.6% of the genomic region were interspersed repeat and tandem repeat elements, respectively. Based on full-length transcriptome data generated by PacBio, 10,903 protein-coding genes were identified. The construction of a genome-wide phylogenetic tree demonstrated that the divergence time of P. haitanensis and Porphyra umbilicalis was ~204.4 Ma. Interspecies comparison revealed that 493 gene families were expanded and that 449 were contracted in the P. haitanensis genome compared with those in the Po. umbilicalis genome. The genome identified is of great value for further research on the genome evolution of red algae and genetic adaptation to intertidal stresses.


Asunto(s)
Cromosomas de las Plantas/genética , Genoma de Planta , Rhodophyta/genética , Filogenia , Proteínas de Plantas/genética , Rhodophyta/clasificación
14.
Int J Biol Macromol ; 142: 634-642, 2020 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-31622715

RESUMEN

The mucoadhesive properties of different types of carrageenan (kappa-, kappa/beta-, iota/kappa- and lambda-CRGs) isolated from red seaweed families Gigartinaceae and Tichocarpaceae collected on the Pacific coast were studied. We examined the interaction between CRGs and pig stomach mucin in dilute aqueous solutions using a set of methods. Measurements of the dynamic light scattering of mucin in the presence of CRG showed that the polysaccharides cause aggregation of mucin particles, as confirmed by microscopy data. The addition of CRGs to solutions of mucin resulted in the formation of a mixture that changed the charge of mucin, especially in the case of kappa- and kappa/beta-CRGs. The interaction between CRG and porcine gastric mucin in the presence of various additives confirmed that hydrogen bonds and electrostatic interactions are complemented when CRG and mucin are mixed in an aqueous medium, which is also confirmed by in vitro methods based on measurements of work of adhesion and shear stress. Kappa- and kappa/beta-CRGs that contain 3,6-anhydro-α-d-galactopyranose chains (DA) have high molecular weight and exhibit a high density of available hydrogen bonding groups able to interact more strongly with mucin glycoproteins.


Asunto(s)
Carragenina/química , Extractos Vegetales/química , Polisacáridos/química , Rhodophyta/clasificación , Algas Marinas/química , Sulfatos/química , Adhesivos , Animales , Galactosa/química , Glicoproteínas/química , Enlace de Hidrógeno , Estructura Molecular , Mucinas/química , Unión Proteica , Electricidad Estática , Estómago , Porcinos
15.
Sci Rep ; 9(1): 12611, 2019 08 30.
Artículo en Inglés | MEDLINE | ID: mdl-31471551

RESUMEN

Crustose coralline algae (CCA) are calcifying red macroalgae that reef build in their own right and perform essential ecosystem functions on coral reefs worldwide. Despite their importance, limited genetic information exists for this algal group. De novo transcriptomes were compiled for four species of common tropical CCA using RNA-seq. Sequencing generated between 66 and 87 million raw reads. Transcriptomes were assembled, redundant contigs removed, and remaining contigs were annotated using Trinotate. Protein orthology analysis was conducted between CCA species and two noncalcifying red algae species from NCBI that have published genomes and transcriptomes, and 978 orthologous protein groups were found to be uniquely shared amongst CCA. Functional enrichment analysis of these 'CCA-specific' proteins showed a higher than expected number of sequences from categories relating to regulation of biological and cellular processes, such as actin related proteins, heat shock proteins, and adhesion proteins. Some proteins found within these enriched categories, i.e. actin and GH18, have been implicated in calcification in other taxa, and are thus candidates for involvement in CCA calcification. This study provides the first comprehensive investigation of gene content in these species, offering insights not only into the evolution of coralline algae but also of the Rhodophyta more broadly.


Asunto(s)
Ecosistema , Rhodophyta/genética , Algas Marinas/genética , Transcriptoma/genética , Animales , Arrecifes de Coral , Regulación de la Expresión Génica/genética , Concentración de Iones de Hidrógeno , RNA-Seq , Rhodophyta/clasificación , Agua de Mar , Algas Marinas/clasificación
16.
Nature ; 572(7768): 240-243, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31316212

RESUMEN

Rhodophyta (red algae) is one of three lineages of Archaeplastida1, a supergroup that is united by the primary endosymbiotic origin of plastids in eukaryotes2,3. Red algae are a diverse and species-rich group, members of which are typically photoautotrophic, but are united by a number of highly derived characteristics: they have relatively small intron-poor genomes, reduced metabolism and lack cytoskeletal structures that are associated with motility, flagella and centrioles. This suggests that marked gene loss occurred around their origin4; however, this is difficult to reconstruct because they differ so much from the other archaeplastid lineages, and the relationships between these lineages are unclear. Here we describe the novel eukaryotic phylum Rhodelphidia and, using phylogenomics, demonstrate that it is a closely related sister to red algae. However, the characteristics of the two Rhodelphis species described here are nearly opposite to those that define red algae: they are non-photosynthetic, flagellate predators with gene-rich genomes, along with a relic genome-lacking primary plastid that probably participates in haem synthesis. Overall, these findings alter our views of the origins of Rhodophyta, and Archaeplastida evolution as a whole, as they indicate that mixotrophic feeding-that is, a combination of predation and phototrophy-persisted well into the evolution of the group.


Asunto(s)
Filogenia , Rhodophyta/clasificación , Rhodophyta/metabolismo , Forma de la Célula , Supervivencia Celular , Genoma , Fotosíntesis , Rhodophyta/citología , Rhodophyta/genética
17.
Proc Natl Acad Sci U S A ; 116(30): 15080-15085, 2019 07 23.
Artículo en Inglés | MEDLINE | ID: mdl-31285351

RESUMEN

Understanding how trophic dynamics drive variation in biodiversity is essential for predicting the outcomes of trophic downgrading across the world's ecosystems. However, assessing the biodiversity of morphologically cryptic lineages can be problematic, yet may be crucial to understanding ecological patterns. Shifts in keystone predation that favor increases in herbivore abundance tend to have negative consequences for the biodiversity of primary producers. However, in nearshore ecosystems, coralline algal cover increases when herbivory is intense, suggesting that corallines may uniquely benefit from trophic downgrading. Because many coralline algal species are morphologically cryptic and their diversity has been globally underestimated, increasing the resolution at which we distinguish species could dramatically alter our conclusions about the consequences of trophic dynamics for this group. In this study, we used DNA barcoding to compare the diversity and composition of cryptic coralline algal assemblages at sites that differ in urchin biomass and keystone predation by sea otters. We show that while coralline cover is greater in urchin-dominated sites (or "barrens"), which are subject to intense grazing, coralline assemblages in these urchin barrens are significantly less diverse than in kelp forests and are dominated by only 1 or 2 species. These findings clarify how food web structure relates to coralline community composition and reconcile patterns of total coralline cover with the widely documented pattern that keystone predation promotes biodiversity. Shifts in coralline diversity and distribution associated with transitions from kelp forests to urchin barrens could have ecosystem-level effects that would be missed by ignoring cryptic species' identities.


Asunto(s)
Biodiversidad , Nutrias/fisiología , Filogenia , Rhodophyta/clasificación , Erizos de Mar/fisiología , Animales , Antozoos/fisiología , Arrecifes de Coral , Código de Barras del ADN Taxonómico , ADN de Algas/genética , Ecosistema , Cadena Alimentaria , Kelp/clasificación , Kelp/genética , Océano Pacífico , Conducta Predatoria/fisiología , Rhodophyta/genética
18.
J Mol Biol ; 431(14): 2543-2553, 2019 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-31078556

RESUMEN

Conformational rearrangements are critical to regulating the assembly and activity of the spliceosome. The spliceosomal protein Prp8 undergoes multiple conformational changes during the course of spliceosome assembly, activation, and catalytic activity. Most of these rearrangements of Prp8 involve the disposition of the C-terminal Jab-MPN and RH domains with respect to the core of Prp8. Here we use x-ray structural analysis to show that a previously characterized and highly conserved ß-hairpin structure in the RH domain that acts as a toggle in the spliceosome is absent in Prp8 from the reduced spliceosome of the red alga Cyanidioschyzon merolae. Using comparative sequence analysis, we show that the presence or absence of this hairpin corresponds to the presence or absence of protein partners that interact with this hairpin as observed by x-ray and cryo-EM studies. The presence of the toggle correlates with increasing intron number suggesting a role in the regulation of splicing.


Asunto(s)
Proteínas Algáceas/química , Proteínas Algáceas/genética , Empalme del ARN/genética , Rhodophyta/genética , Empalmosomas/genética , Secuencia de Aminoácidos , Modelos Moleculares , Conformación Proteica , Rhodophyta/clasificación , Homología de Secuencia
19.
Sci Rep ; 9(1): 578, 2019 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-30679622

RESUMEN

Coralline algae form extensive maerl and rhodolith habitats that support a rich biodiversity. Calcium carbonate harvesting as well as trawling activities threatens this ecosystem. Eleven species were recorded so far as maerl-forming in NE Atlantic, but identification based on morphological characters is unreliable. As for most red algae, we now use molecular characters to resolve identification of these taxa. However, obtaining DNA sequences requires time and resource demanding methods. The purpose of our study was to improve methods for achieving simple DNA extraction, amplification, sequencing and sequence analysis to allow robust identification of maerl species and other coralline algae. Our novel and easy DNA preparation method for coralline algae was of sufficient quality for qPCR amplification and sequencing of all 47 tested samples. The new psbA qPCR assay successfully amplified a 350 bp fragment identifying six species and uncovering two new Operational Taxonomic Units. Molecular results were corroborated with anatomical examination using i.e. scanning electron microscopy. Finally, the qPCR assay was coupled with High Resolution Melt analysis that successfully differentiated the closely related species Lithothamnion erinaceum and L. cf. glaciale. This DNA preparation and qPCR technique should vitalize coralline research by reducing time and cost associated with molecular systematics.


Asunto(s)
Antozoos/microbiología , Código de Barras del ADN Taxonómico/métodos , ADN de Algas/aislamiento & purificación , Desnaturalización de Ácido Nucleico , Complejo de Proteína del Fotosistema II/genética , Rhodophyta/clasificación , Rhodophyta/genética , Animales , ADN de Algas/química , ADN de Algas/genética , Rhodophyta/enzimología
20.
Biol Trace Elem Res ; 187(2): 579-585, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29948911

RESUMEN

This study reports the total concentrations of mineral and trace metals sodium, potassium, calcium, magnesium, phosphorus, iron, copper, zinc, and manganese in the seaweeds Padina tetrastromatica, Turbinaria ornate, Sargassum wightii, Sargassum swartzii, Gracilaria edulis, Ulva lactuca, Chaetomorpha antennina, and Halimeda opuntia collected from mandapam coastal regions, Southeast coast of India. Microwave-assisted digestion was used for sample preparation prior to mineral and trace metal analysis. Mineral and trace metal analyses were determined by inductively coupled plasma mass spectrometry. The ranges of concentrations of mineral and trace metals in algae were 27.04 ± 2.54-194.08 ± 2.36 mg/kg for manganese, 1.88 ± 0.10-121.5 ± 0.70 mg/kg for sodium, 6.5 ± 0.56-90.5 ± 2.12 mg/kg for magnesium, 59.07 ± 0.34-672 ± 2.82 mg/kg for potassium, 13.15 ± 2.08-135.13 ± 1.59 for sulfur, 0.003 ± 0.001-3.44 ± 0.13 mg/kg for cobalt, 0.39 ± 0.19-8.95 ± 0.38 mg/kg for copper, 0.72 ± 0.28-25.72 ± 0.39 mg/kg for zinc, and 6.01 ± 0.27-188.47 ± 1.92 mg/kg for iron.The results were evaluated statistically, and the significant difference was observed in the mean concentrations of all mineral and trace elements, except Co, Cu, and Zn, among the type of seaweeds.


Asunto(s)
Metales/metabolismo , Microondas , Minerales/metabolismo , Algas Marinas/metabolismo , Oligoelementos/metabolismo , Chlorophyta/clasificación , Chlorophyta/metabolismo , Espectrometría de Masas/métodos , Phaeophyceae/clasificación , Phaeophyceae/metabolismo , Rhodophyta/clasificación , Rhodophyta/metabolismo , Algas Marinas/clasificación , Especificidad de la Especie
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