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1.
Sci Total Environ ; 921: 170941, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38360303

RESUMO

The Southern Ocean and the Antarctic Circumpolar Current create environmental conditions that serve as an efficient barrier to prevent the colonization of non-native species (NNS) in the marine ecosystems of Antarctica. However, warming of the Southern Ocean and the increasing number of transport opportunities are reducing the physiological and physical barriers, increasing the chances of NNS arriving. The aim of this study was to determine the limits of survival of the juvenile mussels, M. chilensis, under current Antarctic conditions and those projected under climate change. These assessments were used to define the mussels potential for establishment in the Antarctic region. Experimental mussels were exposed to four treatments: -1.5 °C (Antarctic winter), 2 °C (Antarctic summer), 4 °C (Antarctic projected) and 8 °C (control) for 80 days and a combination of physiological and transcriptomics approaches were used to investigate mussel response. The molecular responses of mussels were congruent with the physiological results, revealing tolerance to Antarctic winter temperatures. However, a higher number of regulated differentially expressed gene (DEGs) were reported in mussels exposed to Antarctic winter temperatures (-1.5 °C). This tolerance was associated with the activation of the biological processes associated with apoptosis (up regulated) and both cell division and cilium assembly (down regulated). The reduced feeding rate and the negative scope for growth, for a large part of the exposure period at -1.5 °C, suggests that Antarctic winter temperatures represents an environmental barrier to M. chilensis from the Magellanic region settling in the Antarctic. Although M. chilensis are not robust to current Antarctica thermal conditions, future warming scenarios are likely to weaken these physiological barriers. These results strongly suggest that the West Antarctic Peninsula could become part of Mytilus distributional range, especially with dispersal aided by increasing maritime transport activity across the Southern Ocean.


Assuntos
Mytilus , Água do Mar , Animais , Mytilus/fisiologia , Ecossistema , Temperatura , Regiões Antárticas , Oceanos e Mares
2.
Artigo em Inglês | MEDLINE | ID: mdl-36495831

RESUMO

Increased carbon dioxide in the atmosphere and its absorption across the ocean surface will alter natural variations in pH and temperature levels, occurring in coastal upwelling ecosystems. The scallop Argopecten purpuratus, one of the most economically important species farmed in northern Chile, has been shown to be vulnerable to these environmental drivers. However, the regulatory responses at the gene-level of scallops to these climate stressors remain almost unknown. Consequently, we used an orthogonal experimental design and RNAseq approach to analyze the acute effects of variability in pH and temperature on gene expression in the muscle tissue of A. purpuratus. In respect to control conditions (pH ~ 8.0/ 14 °C), the influence of low pH (~ 7.7) and temperature (14 °C) induced the activation of several genes associated with apoptotic signaling pathways and protein localization to plasma membrane. Elevated temperature (18 °C) and pH (~8.0) conditions increased the expression of transcripts associated with the activation of muscle contraction, regulation, and sarcomere organization effects on muscle tissue. In scallops exposed to low pH and elevated temperature, the genes expressed were differentially associated with the oxidation-reduction process, signal translation, and positive regulation of GTPase activity. These results indicated that the differentially expressed genes under the experimental conditions tested are mainly related to the mitigation of cellular damage and homeostasis control. Our results add knowledge about the function of the adductor muscle in response to stressors in scallops. Furthermore, these results could help in the identification of molecular biomarkers of stress necessary to be integrated into the aquaculture programs for the mitigation of climate change.


Assuntos
Ecossistema , Pectinidae , Animais , Temperatura , Pectinidae/genética , Aquicultura , Perfilação da Expressão Gênica , Concentração de Íons de Hidrogênio
3.
Biology (Basel) ; 11(12)2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36552233

RESUMO

To study how Odontaster validus can influence the spatial structure of Antarctic benthic communities and how they respond to disturbance, it is necessary to assess potential dietary shifts in different habitats. We investigated the diets of O. validus from Maxwell Bay and South Bay in the West Antarctic Peninsula. A multifaceted approach was applied including in situ observations of cardiac stomach everted contents, isotopic niche, and trophic diversity metrics. Results confirm the flexible foraging strategy of this species under markedly different environmental conditions, suggesting plasticity in resource use. The data also showed evidence of isotopic niche expansion, high δ15N values, and Nacella concinna as a common food item for individuals inhabiting a site with low seasonal sea ice (Ardley Cove), which could have significant ecological implications such as new trophic linkages within the Antarctic benthic community. These results highlight the importance of considering trophic changes of key species to their environment as multiple ecological factors can vary as a function of climatic conditions.

4.
PLoS One ; 17(4): e0266538, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35395031

RESUMO

The clam Ameghynomia antiqua is a highly important resource for fisheries due to its high catches volume. It is the bivalve mollusc with the highest fisheries landings from natural beds on the Pacific coast of southern South America; however, studies of the reproductive conditions of this species are scarce and date back many years. The object of the present work was to evaluate the reproductive characteristics of the species, analysing its gametogenic and gonadal cycle, and reproductive indices, in fishery locations that present the natural beds with the highest fisheries catches, as well as parasite loads in the species. The gonads of the individuals were sampled monthly over a year and classified into one of three states called: "in development", "ripe" and "spawned". Synchrony between the sexes was observed in the indicators of the Gonadosomatic Index and Condition Index in each of the locations, although no synchrony was observed between locations. In the gametogenic cycle, the "ripe" state was observed in females in spring-summer, followed by rapid recovery to new development of the gonads; in males the "ripe" state was observed throughout the year. It was observed that males entered the "spawned" state one month ahead of females. The presence of digenean parasites in the state of metacercariae was detected in the gonads and mantle. No significant differences were found in the prevalence or intensity of infection when analysed by sex and month. The metacercariae were identified, by sequencing of three DNA regions, as belonging to the clade shared by species of the genus Parvatrema and close to the Gymnophalloides; both these genera belong to the family Gymnophallidae of the superclass Digenea. Infection was observed to reduce the gonadal tissue, in some cases causing castration. This is the first record of the presence of these parasites of A. antiqua, with genetic identification at genus level. These results are relevant for act proper management of this resource, which is important for fishing.


Assuntos
Bivalves , Trematódeos , Animais , Bivalves/parasitologia , Feminino , Pesqueiros , Gônadas , Humanos , Masculino , Reprodução , Trematódeos/genética
5.
Sci Rep ; 11(1): 14997, 2021 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-34294855

RESUMO

The polychaete Boccardia wellingtonensis is a poecilogonous species that produces different larval types. Females may lay Type I capsules, in which only planktotrophic larvae are present, or Type III capsules that contain planktotrophic and adelphophagic larvae as well as nurse eggs. While planktotrophic larvae do not feed during encapsulation, adelphophagic larvae develop by feeding on nurse eggs and on other larvae inside the capsules and hatch at the juvenile stage. Previous works have not found differences in the morphology between the two larval types; thus, the factors explaining contrasting feeding abilities in larvae of this species are still unknown. In this paper, we use a transcriptomic approach to study the cellular and genetic mechanisms underlying the different larval trophic modes of B. wellingtonensis. By using approximately 624 million high-quality reads, we assemble the de novo transcriptome with 133,314 contigs, coding 32,390 putative proteins. We identify 5221 genes that are up-regulated in larval stages compared to their expression in adult individuals. The genetic expression profile differed between larval trophic modes, with genes involved in lipid metabolism and chaetogenesis over expressed in planktotrophic larvae. In contrast, up-regulated genes in adelphophagic larvae were associated with DNA replication and mRNA synthesis.


Assuntos
Sequenciamento do Exoma/métodos , Perfilação da Expressão Gênica/métodos , Poliquetos/genética , Proteínas de Protozoários/genética , Animais , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Sequenciamento de Nucleotídeos em Larga Escala , Larva/genética , Masculino
6.
Polar Biol ; 44(7): 1365-1377, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34092908

RESUMO

The systematics of Subantarctic and Antarctic near-shore marine benthic invertebrates requires major revision and highlights the necessity to incorporate additional sources of information in the specimen identification chart in the Southern Ocean (SO). In this study, we aim to improve our understanding of the biodiversity of Kidderia (Dall 1876) through molecular and morphological comparisons of Antarctic and Subantarctic taxa. The microbivalves of the genus Kidderia are small brooding organisms that inhabit intertidal and shallow subtidal rocky ecosystems. This genus represents an interesting model to test the vicariance and dispersal hypothesis in the biogeography of the SO. However, the description of Kidderia species relies on a few morphological characters and biogeographic records that raise questions about the true diversity in the group. Here we will define the specimens collected with genetic tools, delimiting their respective boundaries across provinces of the SO, validating the presence of two species of Kidderia. Through the revision of taxonomic issues and species delimitation, it was possible to report that the Antarctic species is Kidderia subquadrata and the species recorded in the Subantarctic islands Diego Ramirez, South Georgia and the Kerguelen Archipelago is Kidderia minuta. The divergence time estimation suggests the origin and diversification of Kidderia lineages are related to historical vicariant processes probably associated with the separation of the continental landmasses close to the late Eocene. Supplementary Information: The online version contains supplementary material available at 10.1007/s00300-021-02885-6.

7.
Sci Rep ; 11(1): 5705, 2021 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-33707560

RESUMO

It is well established that Antarctic biodiversity has been strongly influenced by rapid climatic fluctuations during the Quaternary. Marine invertebrates from Antarctica constitute an interesting lens through which to study the impacts of the last glacial periods as glaciation impacted the distribution and intraspecific genetic variation of these animals. However, the impact on the spatial genetic distribution and historical demography of local processes in areas adjacent to the West Antarctic Peninsula (WAP) is less clear. Here we present new genetic information on the bivalve Kidderia subquadrata, a small mollusk that inhabits intertidal rocky island ecosystems throughout the WAP. Using a phylogeographical approach, we examined the spatial patterns of genetic diversity in this brooder species to test the hypothesis of strong genetic structure in incubating organisms and the hypothesis of glacial refugia in organisms with limited dispersion. We found evidence of strong genetic structure among populations of the WAP and a recent expansion in the South Shetland Islands. Our findings are concordant with the predictions that incubating organisms, abundant in Antarctica, present a strong genetic structure among their populations and also support the hypothesis of glacial refugia in organisms with limited dispersion. The effect of the coastal current pattern in the WAP is suggested as a driver to the local spatial dynamics of the genetic diversity distribution. Although genetic information about this microbivalve is still scarce, the knowledge reported here has increased our understanding of the evolutionary patterns of this organism that is endemic to the Southern Ocean.

8.
PeerJ ; 9: e12679, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35036155

RESUMO

The Western Antarctic Peninsula (WAP) is a hotspot for environmental change and has a strong environmental gradient from North to South. Here, for the first time we used adult individuals of the bivalve Aequiyoldia eightsii to evaluate large-scale spatial variation in the biochemical composition (measured as lipid, protein and fatty acids) and energy content, as a proxy for nutritional condition, of three populations along the WAP: O'Higgins Research Station in the north (63.3°S), Yelcho Research Station in mid-WAP (64.9°S) and Rothera Research Station further south (67.6°S). The results reveal significantly higher quantities of lipids (L), proteins (P), energy (E) and total fatty acids (FA) in the northern population (O'Higgins) (L: 8.33 ± 1.32%; P: 22.34 ± 3.16%; E: 171.53 ± 17.70 Joules; FA: 16.33 ± 0.98 mg g) than in the mid-WAP population (Yelcho) (L: 6.23 ± 0.84%; P: 18.63 ± 1.17%; E: 136.67 ± 7.08 Joules; FA: 10.93 ± 0.63 mg g) and southern population (Rothera) (L: 4.60 ± 0.51%; P: 13.11 ± 0.98%; E: 98.37 ± 5.67 Joules; FA: 7.58 ± 0.48 mg g). We hypothesize these differences in the nutritional condition could be related to a number of biological and environmental characteristics. Our results can be interpreted as a consequence of differences in phenology at each location; differences in somatic and gametogenic growth rhythms. Contrasting environmental conditions throughout the WAP such as seawater temperature, quantity and quality of food from both planktonic and sediment sources, likely have an effect on the metabolism and nutritional intake of this species.

9.
R Soc Open Sci ; 7(9): 200603, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33047024

RESUMO

The Antarctic Circumpolar Current (ACC) dominates the open-ocean circulation of the Southern Ocean, and both isolates and connects the Southern Ocean biodiversity. However, the impact on biological processes of other Southern Ocean currents is less clear. Adjacent to the West Antarctic Peninsula (WAP), the ACC flows offshore in a northeastward direction, whereas the Antarctic Peninsula Coastal Current (APCC) follows a complex circulation pattern along the coast, with topographically influenced deflections depending on the area. Using genomic data, we estimated genetic structure and migration rates between populations of the benthic bivalve Aequiyoldia eightsii from the shallows of southern South America and the WAP to test the role of the ACC and the APCC in its dispersal. We found strong genetic structure across the ACC (between southern South America and Antarctica) and moderate structure between populations of the WAP. Migration rates along the WAP were consistent with the APCC being important for species dispersal. Along with supporting current knowledge about ocean circulation models at the WAP, migration from the tip of the Antarctic Peninsula to the Bellingshausen Sea highlights the complexities of Southern Ocean circulation. This study provides novel biological evidence of a role of the APCC as a driver of species dispersal and highlights the power of genomic data for aiding in the understanding of the influence of complex oceanographic processes in shaping the population structure of marine species.

10.
Sci Rep ; 10(1): 5552, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32218472

RESUMO

Global biodiversity is both declining and being redistributed in response to multiple drivers characterizing the Anthropocene, including synergies between biological invasions and climate change. The Antarctic marine benthos may constitute the last biogeographic realm where barriers (oceanographic currents, climatic gradients) have not yet been broken. Here we report the successful settlement of a cohort of Mytilus cf. platensis in a shallow subtidal habitat of the South Shetland Islands in 2019, which demonstrates the ability of this species to complete its early life stages in this extreme environment. Genetic analyses and shipping records show that this observation is consistent with the dominant vectors and pathways linking southern Patagonia with the Antarctic Peninsula and demonstrates the potential for impending invasions of Antarctic ecosystems.


Assuntos
Bivalves/classificação , Bivalves/fisiologia , Complexo IV da Cadeia de Transporte de Elétrons/genética , RNA Ribossômico 16S/genética , Animais , Regiões Antárticas , Biodiversidade , Mudança Climática , Espécies Introduzidas , Filogenia , Dinâmica Populacional , Análise de Sequência de DNA/métodos , América do Sul
11.
Mar Genomics ; 52: 100736, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31883640

RESUMO

Poecilogony is a type of reproduction in which a species produces different types of larvae. Boccardia wellingtonensis, is a poecilogonous polychaete with females producing planktotrophic and adelphophagic larvae, in addition to nurse eggs, in the same capsule that differ in feeding behavior. It is still unclear why planktotrophs do not feed on nurse eggs during the intracapsular development and arrest its growth, while adelphophagic larvae consume nurse eggs and planktotrophic larvae inside the capsule, hatching as advance larvae or as juveniles. Here we characterized the expression of selected miRNAs from these two types of larvae and from adults in order to begin to understand the molecular mechanisms that regulate expression in this type of poecilogony. Results showed that adults and pre-hatching adelphophagic larvae have high levels of expression of miR-125, miR-87a and let-7, while adelphophages at early developmental stage had low levels of expression of miR-87b. Planktotrophic larvae showed low expression level of let-7. This work represents the first step in understanding the role of miRNAs in the development of different larval types in a poecilogonous species. We also propose to B. wellingtonensis as an interesting biological model to study the evolution of larval modes and reproductive strategies of marine invertebrates.


Assuntos
Expressão Gênica , MicroRNAs/genética , Poliquetos/genética , Animais , Comportamento Alimentar , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , MicroRNAs/metabolismo , Poliquetos/crescimento & desenvolvimento , Poliquetos/fisiologia , Reprodução
12.
Parasitol Int ; 67(2): 159-169, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29079224

RESUMO

The most studied digenean of marine organisms in Chile is by far Proctoeces humboldti, a parasite of the intestine of the clingfish Sicyases sanguineus and gonad of the keyhole limpet Fissurella spp. (progenetic metacercariae). The mussel Perumytilus purpuratus has been suggested as the first intermediate host for this digenean. In a study examining the parasites of S. sanguineus from central Chile, we found specimens of Proctoeces showing significant morphological differences with P. humboldti. To assist in the resolution of the taxonomic identification of these specimens, as well sporocysts obtained from the mussel P. purpuratus from central and northern Chile, phylogenetic studies using DNA sequences from the SSU rRNA, as well the LSU rRNA and Cox 1 gene were performed. Results showed that the clingfish S. sanguineus is a host for two species of Proctoeces (P. humboldti and P. syciases n. sp.) along the northern and central Chilean coast, without geographic separation; the mussel P. purpuratus is the first intermediate host for P. syciases n. sp. but not for P. humboldti in central and northern Chile. Fissurellids (Archaeogastropoda) along the Chilean coast harbor only progenetic stages of P. humboldti, but there is no evidence of progenesis for P. syciases. The reinstatement of Proctoeces humboldti is strongly suggested.


Assuntos
Doenças dos Peixes/parasitologia , Peixes/parasitologia , Filogenia , Trematódeos/genética , Trematódeos/isolamento & purificação , Animais , Bivalves/anatomia & histologia , Bivalves/parasitologia , Chile/epidemiologia , Doenças dos Peixes/epidemiologia , Gônadas/parasitologia , Trematódeos/anatomia & histologia , Trematódeos/classificação , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/parasitologia
13.
J Therm Biol ; 68(Pt A): 104-109, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28689711

RESUMO

Marine ectotherms inhabiting intertidal and shallow subtidal environments are continuously exposed to diurnal tidal cycles and seasonal variability in temperature. These organisms have adaptive mechanisms to maintain cellular homeostasis, irrespective of thermal environmental variation. In this study, we describe the molecular responses to thermal stress in the edible sea urchin Loxechinus albus. In particular, we determined the differential expression of a set of molecular markers that have been identified as targets of stress-related responses. These include the heat shock proteins (hsp70 and hsp90), cell detoxification proteins (cytochrome P450), and osmorregulatory proteins (α and ß - Na+/K+ATPase). We exposed individuals to different temperatures; a warm treatment (18±1.0°C), a cold treatment (10±1.0°C), and a control treatment (average local temperature of 14±1.0°C) and differential expression was quantified after 2, 6, 12 and 48h of exposure. Levels of mRNA were quantified by reverse transcription-quantitative polymerase chain reaction, and the relative expression of each gene was calculated using the 18S rRNA gene as a reference, and the control treatment as a calibrator. We found that the expression levels of all studied genes increased during exposure to warmth. The largest increase in expression was observed in cytochrome p450 genes (ca. sixteen-fold); this was followed by increases in the expression of the Na+/K+ATPase (ca. eight-fold) and by the hsp (ca. six fold) genes. These results indicate that sea urchin thermal stress responses depend on differential gene-regulation, involving heat-shock, membrane potential, and detoxification genes that generate an integrated adaptive response to acute environmental changes.


Assuntos
Regulação da Expressão Gênica/fisiologia , Ouriços-do-Mar/genética , Estresse Fisiológico/genética , Animais , Termotolerância/genética
14.
Ecol Evol ; 7(11): 3773-3783, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28616174

RESUMO

Potential interactions between marine predators and humans arise in the southern coast of Chile where predator feeding and reproduction sites overlap with fisheries and aquaculture. Here, we assess the potential effects of intensive salmon aquaculture on food habits, growth, and reproduction of a common predator, the spiny dogfish-identified as Squalus acanthias via genetic barcoding. A total of 102 (89 females and 13 males) individuals were collected during winter and summer of 2013-2014 from the Chiloé Sea where salmon aquaculture activities are concentrated. The low frequency of males in our study suggests spatial segregation of sex, while immature and mature females spatially overlapped in both seasons. Female spiny dogfish showed a functional specialist behavior as indicated by the small number of prey items and the relative high importance of the austral hake and salmon pellets in the diet. Immature sharks fed more on pellets and anchovies than the larger hake-preferring mature females. Our results also indicate that spiny dogfish switch prey (anchovy to hake) to take advantage of seasonal changes in prey availability. Despite differences in the trophic patterns of S. acanthias due to the spatial association with intensive salmon farming, in this region, there appears to be no difference in fecundity or size at maturity compared to other populations. Although no demographic effects were detected, we suggest that a range of additional factors should be considered before concluding that intensive aquaculture does not have any impact on these marine predators.

15.
Sci Rep ; 6: 36516, 2016 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-27805042

RESUMO

The edible sea urchin Loxechinus albus (Molina, 1782) is a keystone species in the littoral benthic systems of the Pacific coast of South America. The international demand for high-quality gonads of this echinoderm has led to an extensive exploitation and decline of its natural populations. Consequently, a more thorough understanding of L. albus gonad development and gametogenesis could provide valuable resources for aquaculture applications, management, conservation and studies about the evolution of functional and structural pathways that underlie the reproductive toolkit of marine invertebrates. Using a high-throughput sequencing technology, we explored the male gonad transcriptome of this highly fecund sea urchin. Through a de novo assembly approach we obtained 42,530 transcripts of which 15,544 (36.6%) had significant alignments to known proteins in public databases. From these transcripts, approximately 73% were functionally annotated allowing the identification of several candidate genes that are likely to play a central role in developmental processes, nutrient reservoir activity, sexual reproduction, gamete generation, meiosis, sex differentiation, sperm motility, male courtship behavior and fertilization. Additionally, comparisons with the male gonad transcriptomes of other echinoderms revealed several conserved orthologous genes, suggesting that similar functional and structural pathways underlie the reproductive development in this group and other marine invertebrates.


Assuntos
Bases de Dados de Ácidos Nucleicos , Perfilação da Expressão Gênica , Ouriços-do-Mar , Testículo/metabolismo , Transcriptoma/fisiologia , Animais , Masculino , Ouriços-do-Mar/genética , Ouriços-do-Mar/metabolismo
16.
J Parasitol ; 101(6): 694-700, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26221995

RESUMO

The opecoelid Helicometrina nimia Linton, 1910 has been reported from numerous marine fishes along the Pacific and Atlantic coasts of the Americas. Along the Chilean coast, H. nimia is found in fishes belonging to at least 9 families. This surprisingly low host specificity of H. nimia raises question about the correct identification of specimens assigned to this species. Here we evaluate whether H. nimia specimens isolated from sympatric fish species in northern Chile but with different diets and found in different habitats (water column and demersal) are the same species. Our results demonstrate that specimens from the shallow benthic fish Labrisomus philippii (Steindachner) do not correspond to H. nimia but instead belong to a new species of Helicometrina. This species is described and distinguished from H. nimia using morphological descriptions and 2 molecular markers (the cytochrome c oxidase subunit 1 gene and the V4 region of the SSU rRNA gene). The new species Helicometrina labrisomi (Digenea: Opecoelidae), is found in the intestine of L. philippii (Steindachner, 1866) (Pisces: Labrisomidae), a shallow benthic fish that inhabits the northern coast of Chile. We also studied the related Helicometrina nimia Linton, 1910 from the benthopelagic fishes Paralabrax humeralis (Valenciennes, 1828) and Acanthistius pictus (Tschudi, 1846) (Serranidae). The new species differs from H. nimia by a combination of characters that include ovary shape, number of uterine loops, and position of the genital pore. Our results indicate that morphological characteristics, such as body size, extent of the vitellarium, shape of the testes, and cirrus sac size and extent, traditionally used in the taxonomy of Helicometrina are highly variable. In contrast, meristic and morphological characteristics, such as a lobed ovary, the number of uterine loops, dimensions of the pharynx, and the opening of the genital pore, are highly constant.


Assuntos
Bass/parasitologia , Doenças dos Peixes/parasitologia , Enteropatias Parasitárias/veterinária , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Animais , Chile , Dieta/veterinária , Ecossistema , Complexo IV da Cadeia de Transporte de Elétrons/genética , Peixes , Haplótipos , Enteropatias Parasitárias/parasitologia , Filogenia , RNA Ribossômico 18S/genética , Alinhamento de Sequência , Trematódeos/anatomia & histologia , Trematódeos/genética , Trematódeos/isolamento & purificação , Infecções por Trematódeos/parasitologia
17.
Mol Biol Rep ; 42(6): 1081-9, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25433433

RESUMO

The edible Chilean red sea urchin, Loxechinus albus, is the only species of its genus and endemic to the Southeastern Pacific. In this study, we reconstructed the mitochondrial genome of L. albus by combining Sanger and pyrosequencing technologies. The mtDNA genome had a length of 15,737 bp and encoded the same 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes as other animal mtDNAs. The size of this mitogenome was similar to those of other Echinodermata species. Structural comparisons showed a highly conserved structure, composition, and gene order within Echinoidea and Holothuroidea, and nearly identical gene organization to that found in Asteroidea and Crinoidea, with the majority of differences explained by the inversions of some tRNA genes. Phylogenetic reconstruction supported the monophyly of Echinozoa and recovered the monophyletic relationship of Holothuroidea and Echinoidea. Within Holothuroidea, Bayesian and maximum likelihood analyses recovered a sister-group relationship between Dendrochirotacea and Aspidochirotida. Similarly within Echinoidea, these analyses revealed that L. albus was closely related to Paracentrotus lividus, both being part of a sister group to Strongylocentrotidae and Echinometridae. In addition, two major clades were found within Strongylocentrotidae. One of these clades comprised all of the representative species Strongylocentrotus and Hemicentrotus, whereas the other included species of Mesocentrotus and Pseudocentrotus.


Assuntos
Equinodermos/genética , Genoma Mitocondrial/genética , Genômica/métodos , Ouriços-do-Mar/genética , Animais , DNA Mitocondrial/química , DNA Mitocondrial/classificação , DNA Mitocondrial/genética , Equinodermos/classificação , Ordem dos Genes , Filogenia , Análise de Sequência de DNA , Especificidade da Espécie
18.
Mar Genomics ; 18 Pt B: 89-91, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24975986

RESUMO

The southern tip of South America and Antarctica are particularly interesting due to many genera and also species currently sharing between both areas. The genus Nacella (Patellogastropoda: Nacellidae) is distributed in different regions of South America and Antarctica living preferentially on rocks and boulders and grazing on algae, diatoms and bacterial films. We described the transcriptomes of three Nacella species, Nacella concinna (Strebel, 1908), inhabiting the Antarctic Peninsula; Nacella magallanica (Gmelin, 1791), from Patagonia and Nacella clypeater (Lesson, 1831), from central Chile. In total, we obtained over 20,000 contigs with an average length of 583bp. Homologous protein coding genes (PCGs) for mitochondrial genome of the three species were characterized and a database of molecular markers was also generated. This study represents the first publicly available report on pyrosequencing data for patellogastropod species, and provides an important comparative resource for studies in ecophysiology and evolutionary adaptation in marine invertebrate species.


Assuntos
Distribuição Animal , Gastrópodes/genética , Gastrópodes/metabolismo , Transcriptoma/genética , Animais , Regiões Antárticas , Argentina , Sequência de Bases , Chile , Mapeamento de Sequências Contíguas , Primers do DNA/genética , Etiquetas de Sequências Expressas/metabolismo , Perfilação da Expressão Gênica , Ontologia Genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Repetições de Microssatélites , Dados de Sequência Molecular , Análise de Sequência de DNA , Especificidade da Espécie
19.
PLoS One ; 8(8): e71577, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23977079

RESUMO

Aplochiton is a small genus of galaxiid fishes endemic to Patagonia and the Falkland Islands whose taxonomy is insufficiently resolved. Recent genetic analyses confirmed the existence of only two closely related species, Aplochiton taeniatus and Aplochiton zebra, while a third controversial species, Aplochiton marinus, remained lost to synonymy with A. taeniatus. Using an integrative taxonomy framework, we studied original samples and published sequences from a broad range in western Patagonia and the Falkland Islands, and generated robust species hypotheses based on single-locus (Cytochrome Oxidase subunit I; COI) species-delineation methods and known diagnostic morphological characters analyzed in a multivariate context. Results revealed three distinct evolutionary lineages that morphologically resemble, in important respects, existing nominal species descriptions. Interestingly, the lineage associated with A. marinus was unambiguously identifiable (100% accuracy) both from the genetic and morphological viewpoints. In contrast, the morphology of A. taeniatus and A. zebra overlapped substantially, mainly due to the high variability of A. taeniatus. Discriminant function analysis aided the identification of these species with 83.9% accuracy. Hence, for their unambiguous identification, genetic screening is needed. A. marinus has seldom been documented, and when recorded, it has always been found in sites with clear marine influence. It is possible that only A. marinus preserves a life cycle related to the sea akin to the hypothesized ancestral galaxiid. We did not find evidence of claimed diadromy in A. taeniatus or A. zebra, and, therefore, these should be regarded as freshwater species. Finally, a lack of phylogeographic patterns and overrepresentation of uncommon haplotypes suggested demographic expansions in recent evolutionary time, especially of A. zebra, in line with the hypothesis of large-scale range expansion and lineage spread in western Patagonia.


Assuntos
Variação Genética , Osmeriformes/classificação , Osmeriformes/genética , Animais , Evolução Biológica , Conservação dos Recursos Naturais , Análise Discriminante , Ilhas Malvinas , Geografia , Haplótipos/genética , Funções Verossimilhança , Osmeriformes/anatomia & histologia , Especificidade da Espécie
20.
Mar Genomics ; 4(3): 197-205, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21867972

RESUMO

The marine gastropod Concholepas concholepas, locally known as the "loco", is the main target species of the benthonic Chilean fisheries. Genetic and genomic tools are necessary to study the genome of this species in order to understand the molecular basis of its development, growth, and other key traits to improve the management strategies and to identify local adaptation to prevent loss of biodiversity. Here, we use pyrosequencing technologies to generate the first transcriptomic database from adult specimens of the loco. After trimming, a total of 140,756 Expressed Sequence Tag sequences were achieved. Clustering and assembly analysis identified 19,219 contigs and 105,435 singleton sequences. BlastN analysis showed a significant identity with Expressed Sequence Tags of different gastropod species available in public databases. Similarly, BlastX results showed that only 895 out of the total 124,654 had significant hits and may represent novel genes for marine gastropods. From this database, simple sequence repeat motifs were also identified and a total of 38 primer pairs were designed and tested to assess their potential as informative markers and to investigate their cross-species amplification in different related gastropod species. This dataset represents the first publicly available 454 data for a marine gastropod endemic to the southeastern Pacific coast, providing a valuable transcriptomic resource for future efforts of gene discovery and development of functional markers in other marine gastropods.


Assuntos
Gastrópodes/genética , Gastrópodes/metabolismo , Genômica/métodos , Animais , Etiquetas de Sequências Expressas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Biblioteca Gênica , Transcriptoma
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