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1.
Mar Environ Res ; 171: 105477, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34520892

RESUMO

We investigated stratigraphic changes in mollusk death assemblages and geochemistry in sediment cores from four seagrass beds and one unvegetated site in the Gulf of Guanahacabibes (GG), NW Cuba. There was a transition from mangrove to seagrass beds, associated with sea level rise ∼6000 years ago. Sediment accumulation rates during the last century showed a general rise, but increased sharply after ∼1980, likely because of human activities. The GG displayed overall high mollusk γ-diversity, and our estimate of 189 species is biased toward the low end. High ß-diversity was driven by inter-site differences in grain size, vegetation cover, and nutrient input. Spatial heterogeneity within the basin influenced downcore abundance and diversity metrics, highlighting the influence of local drivers. Herbivorous gastropods dominated in seagrass beds and suspension feeder bivalves were dominant on sandy bottom. In the top parts of cores, species richness declined at two sites that were subject to high, human-mediated bulk sedimentation rates and eutrophication. Conservation measures are needed to preserve this hotspot of marine diversity.


Assuntos
Biodiversidade , Chumbo , Animais , Cuba , Sedimentos Geológicos , Humanos , Moluscos
2.
Nature ; 597(7876): 360-365, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34526707

RESUMO

Fish and other aquatic foods (blue foods) present an opportunity for more sustainable diets1,2. Yet comprehensive comparison has been limited due to sparse inclusion of blue foods in environmental impact studies3,4 relative to the vast diversity of production5. Here we provide standardized estimates of greenhouse gas, nitrogen, phosphorus, freshwater and land stressors for species groups covering nearly three quarters of global production. We find that across all blue foods, farmed bivalves and seaweeds generate the lowest stressors. Capture fisheries predominantly generate greenhouse gas emissions, with small pelagic fishes generating lower emissions than all fed aquaculture, but flatfish and crustaceans generating the highest. Among farmed finfish and crustaceans, silver and bighead carps have the lowest greenhouse gas, nitrogen and phosphorus emissions, but highest water use, while farmed salmon and trout use the least land and water. Finally, we model intervention scenarios and find improving feed conversion ratios reduces stressors across all fed groups, increasing fish yield reduces land and water use by up to half, and optimizing gears reduces capture fishery emissions by more than half for some groups. Collectively, our analysis identifies high-performing blue foods, highlights opportunities to improve environmental performance, advances data-poor environmental assessments, and informs sustainable diets.


Assuntos
Aquicultura , Ecossistema , Monitoramento Ambiental , Alimentos Marinhos , Desenvolvimento Sustentável , Animais , Aquicultura/tendências , Mudança Climática , Dieta , Ecologia , Política Ambiental , Pesqueiros , Abastecimento de Alimentos/métodos , Gases de Efeito Estufa , Humanos , Moluscos , Nitrogênio , Fósforo , Alimentos Marinhos/provisão & distribuição , Alga Marinha , Desenvolvimento Sustentável/tendências
3.
Analyst ; 146(20): 6288-6296, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34549732

RESUMO

Increased acidification of aquatic habitats due to climate change is damaging mollusks. Non-destructive methods for analysis are necessary to study these endangered species. We analyzed five Unionidae gastropods using Raman spectroscopy. Shells were primarily composed of aragonite, a polymorph of calcium carbonate found in shell microstructure. Lattice mode Raman peaks from vaterite, a thought to be rare polymorph of calcium carbonate, were identified in each mollusk. Vaterite is present in mollusks at instances of shell damage and subsequent repair. We demonstrate that Raman spectroscopy is sensitive to vaterite, and it may not be as rare as previously thought. We also collected Raman spectra across the interior of Lampsillis fasciola. This data was analyzed through multivariate analysis, combining Principal Component Analysis with Linear Discriminant Analysis (PCA-LDA). Results of PCA-LDA correlate with growth of the mollusks, demonstrating that Raman spectroscopy combined with multivariate analysis could be used to monitor shell growth.


Assuntos
Moluscos , Análise Espectral Raman , Animais , Carbonato de Cálcio , Análise Discriminante , Água Doce , Análise de Componente Principal
4.
Int J Mol Sci ; 22(11)2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34206018

RESUMO

In the mid-1950s, Bert Lester Vallee and his colleague Marvin Margoshes discovered a molecule referred to today as metallothionein (MT). Meanwhile, MTs have been shown to be common in many biological organisms. Despite their prevalence, however, it remains unclear to date what exactly MTs do and how they contribute to the biological function of an organism or organ. We investigate why biochemical research has not yet been able to pinpoint the function(s) of MTs. We shall systematically examine both the discovery of and recent research on Dr. Vallee's beloved family of MT proteins utilizing tools from philosophy of science. Our analysis highlights that Vallee's initial work exhibited features prototypical of a developing research tradition: it was upward-looking, exploratory, and utilized mere interactions. Since the 1960s, MT research has increasingly become intervention- and hypothesis-based while it remained largely upward-looking in character. Whilst there is no reason to think that upward-looking research cannot successfully yield structure-function mappings, it has not yet been successful in the case of MTs. Thus, we suggest it might be time to change track and consider other research strategies looking into the evolution of MTs. Recent studies in mollusks render research in this direction worthy of pursuit.


Assuntos
Metalotioneína/genética , Moluscos/genética , Relação Estrutura-Atividade , Animais , Metalotioneína/isolamento & purificação , Metalotioneína/metabolismo , Metalotioneína/ultraestrutura , Moluscos/metabolismo
5.
Ultrason Sonochem ; 77: 105670, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34304120

RESUMO

This study aims to investigate effects of ultrasound assisted extraction on the abalone viscera protein extraction rate and iron-chelating activity of peptides. The optimal conditions for ultrasound assisted extraction by response surface methodology was at sodium hydroxide concentration 14 g/kg, ultrasonic power 428 W and extraction time 52 min. Under the optimal conditions, protein extraction rate was 64.89%, compared with alkaline extraction of 55.67%. The iron-chelating activity of peptides affected by ultrasound technology was further evaluated by iron-chelating rate, FTIR spectroscopy and LC-HRMS/MS. Alcalase was the suitable enzyme for the preparation of iron-chelating peptides from two abalone viscera proteins, showing no significant difference between their iron-chelating rate of 16.24% (ultrasound assisted extraction) and 16.60% (alkaline extraction). Iron binding sites from the two hydrolysates include amino and carboxylate terminal groups and peptide bond of the peptide backbone as well as amino, imine and carboxylate from side chain groups. Moreover, 24 iron-chelating peptides were identified from hydrolysate (alcalase, ultrasound assisted extraction), which were different from the 27 iron-chelating peptides from hydrolysate (alcalase, alkaline extraction). This study suggests the application of ultrasound technology in the generation of abalone viscera-derived iron-chelating peptides which have the ability to combat iron deficiency.


Assuntos
Fracionamento Químico/métodos , Quelantes de Ferro/isolamento & purificação , Quelantes de Ferro/farmacologia , Moluscos , Proteínas/isolamento & purificação , Proteínas/farmacologia , Ondas Ultrassônicas , Vísceras , Animais
6.
Mar Pollut Bull ; 171: 112703, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34330002

RESUMO

The Eastern Mediterranean Sea hosts more non-indigenous species than any other marine region, yet their impacts on the native biota remain poorly understood. Focusing on mollusks from the Israeli rocky intertidal, we explored the hypothesis that this abiotically harsh habitat supports a limited trait diversity, and thus may promote niche overlap and competition between native and non-indigenous species. Indeed, native and non-indigenous assemblage components often had a highly similar trait composition, caused by functionally similar native (Patella caerulea) and non-indigenous (Cellana rota) limpets. Body size of P. caerulea decreased with increasing C. rota prevalence, but not vice versa, indicating potential asymmetric competition. Although both species have coexisted in Israel for >15 years, a rapid 'replacement' of native limpets by C. rota has been reported for a thermally polluted site, suggesting that competition and regionally rapid climate-related seawater warming might interact to progressively erode native limpet performance along the Israeli coast.


Assuntos
Gastrópodes , Animais , Ecossistema , Mar Mediterrâneo , Moluscos , Água do Mar
7.
J Proteomics ; 245: 104294, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34091091

RESUMO

In this compilation we collect information about the main protein components in hemolymph and stress the continued interest in their study. The reasons for such an attention span several areas of biological, veterinarian and medical applications: from the notions for better dealing with the species - belonging to phylum Arthropoda, subphylum Crustacea, and to phylum Mollusca - of economic interest, to the development of 'marine drugs' from the peptides that, in invertebrates, act as antimicrobial, antifungal, antiprotozoal, and/or antiviral agents. Overall, the topic most often on focus is that of innate immunity operated by classes of pattern-recognition proteins. SIGNIFICANCE: The immune response in invertebrates relies on innate rather than on adaptive/acquired effectors. At a difference from the soluble and membrane-bound immunoglobulins and receptors in vertebrates, the antimicrobial, antifungal, antiprotozoal and/or antiviral agents in invertebrates interact with non-self material by targeting some common (rather than some highly specific) structural motifs. Developing this paradigm into (semi) synthetic pharmaceuticals, possibly optimized through the modeling opportunities offered by computational biochemistry, is one of the lessons today's science may learn from the study of marine invertebrates, and specifically of the proteins and peptides in their hemolymph.


Assuntos
Artrópodes , Hemolinfa , Animais , Organismos Aquáticos , Invertebrados , Moluscos
8.
BMC Ecol Evol ; 21(1): 133, 2021 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-34174830

RESUMO

BACKGROUND: Expression of sexual dimorphism is recognised in various fossil groups of molluscs such as the Ammonoidea, an extinct group of shelled cephalopods. During the Mesozoic, the best-documented sexual dimorphic examples are seen in the Jurassic superfamily Perisphinctoidea. It is usually expressed by distinct adult size and apertural modifications between the antidimorphs. Putative males (otherwise referred to as microconch) are small in size and develop lappets at the end of the shell while the females (macroconch) are larger and bear a simple peristome. Dubious cases are, however, known in that superfamily, which often relate to taxonomic biases or lack of diagnostic characters, and some others expose ontogenetic anomalies illustrated by 'sex reversals' in the shell morphology and ornamentation. RESULTS: The discovery of two specimens of the Callovian Aspidoceratidae Peltoceras athleta (Phillips), having both female and male features, questions the significance and causes of 'sex reversals' in the Ammonoidea. The two specimens have started with the macroconch ontogeny of Peltoceras athleta and show an apparent change toward maleness in the adult, as illustrated by their rounded whorl section, ribs retroversion, fading of the tubercles and lappets typical of the microconchs. Few other cases of female-to-male, as well as male-to-female 'sex reversal', are known in the fossil record, all belonging to the Jurassic Perisphinctoidea (families Perisphinctidae or Aspidoceratidae). Since all Jurassic Perisphinctoidea are strictly gonochoristic, these 'sex reversals' are pathological in nature and are herein referred to as a new forma-type pathology: namely "forma hermaphrodita". CONCLUSIONS: In the absence of any clear evidence of injury or parasitism, we hypothesize that such "forma hermaphrodita" individuals illustrate pathologic cases of intersexuality. Little is known about the ammonoid soft parts, and it is not possible to determine which internal sexual organs occur in specimens having both male and female external shell features. Abnormal feminisation and/or masculinisation also occur in modern cephalopods, the latter also grouping only gonochoric species. This phenomenon is similarly illustrated by a change in the adult body size and a mixing of both female and male structures. In that case, intersexuality is either advantageous in the population or caused sterility. The causes of intersexuality are not clearly established but environmental pollutants are evoked in modern cephalopods because they act as endocrine disrupters. 'Sex reversals' and/or non-functional reproductive abnormalities have also been caused by endocrine disrupters in various gonochoric gastropods species, but infestation, genetic abnormalities, temperature fluctuations or viruses are multiple causes, which can stimulate or inhibit neural-endocrinal activity by direct gonadal influence, and ultimately lead to feminisation or masculinisation in fishes, isopods, crustaceans, and gastropods as well. Regardless of whether "forma hermaphrodita" is due to an exogenic or endogenic cause, the record of intersex Perisphinctoidea in the Jurassic can be explained by the ready recognition of dimorphic pairs, and the easy collection of large and sufficiently preserved fossil palaeopopulations in which intersex specimens have statistically more chance to be found.


Assuntos
Cefalópodes , Transtornos do Desenvolvimento Sexual , Animais , Crustáceos , Feminino , Fósseis , Humanos , Masculino , Moluscos
9.
J Environ Manage ; 291: 112671, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33964622

RESUMO

Initiatives of artisanal fisheries co-management and the construction of differentiated markets for seafood products have been emerging in different parts of the world, as an institutionalized way of coping with a global fishery crisis. This paper analyses some institutionalization processes of artisanal mollusc fisheries, considering the role of co-management in two Brazilian and Italian protected areas (Resex Pirajubaé and Conero Regional Park). Within a theoretical framework aiming at moving beyond the dualism between nature and society, the methodology of multiple-case-study has been used to carry on research about mollusc artisanal fisheries co-management networks in their constitution and development. The paper analyses how these networks are organised in the two contexts and the relations social actors have been developing for a sustainable fishery as a possible way to influence and increase their capacity to address environmental crisis. In the artisanal mollusc fishery co-management experiences, fishers' participation may favour institutional innovations and the co-management networks stability may be generated by the institutions legitimacy. Furthermore, the case studies offer complementary insights to better understand the linkage between artisanal fishery institutionalization processes, common natural resources co-management and value aggregation for traditional seafood. Artisanal mollusc fishery co-management experiences should be stimulated and investigated since they can help in diagnosing early climate and environmental changes in the oceans.


Assuntos
Conservação dos Recursos Naturais , Pesqueiros , Animais , Brasil , Peixes , Itália , Moluscos
10.
Vet Parasitol ; 292: 109395, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33812344

RESUMO

The aim of this study was to assess the effect of pasture molluscicide treatment on the prevalence and severity of small lungworm infections, and the productivity of lambs grazing improved pastures in southeastern Australia. A randomised control field trial of 260 Merino-cross lambs was conducted on a commercially managed farm in South Australia with a history of high small lungworm prevalence. Separate groups of lambs rotationally grazed irrigated lucerne paddocks treated with iron chelate molluscicide or untreated control paddocks. Lambs were monitored every 2-6 weeks from weaning until slaughter with liveweight, lungworm and gastrointestinal nematode infection status measured. At slaughter indicators of small lungworm infection via inspection and carcass characteristics were assessed. The density of the intermediate host snail and lucerne pasture availability were also measured. There was a higher population of adult Prietocella barbara molluscs in the Control paddocks compared to the Treatment paddocks after molluscicide had been applied and prior to grazing commencing (206 vs. 14 snails/m2, respectively; P = 0.03; 95 % CI 8, 528). However, the overall mollusc density was similar between Control and Treatment. The prevalence of small lungworm infections was quite low during the trial (0-13 %), in both Control and Treatment lambs, except at day 94 when 48 % of 28 Control lambs were positive compared to none of 27 Treatment lambs (P < 0.001; 95 % CI 30, 66). A similar proportion of Treatment and Control lambs had evidence of small lungworm infection lesions at slaughter (both 67.8 %). Control lambs grew slightly faster than Treatment lambs, with an average daily gain of 202 (± 3 SEM) g/head/day for Control and 190 (± 4 SEM) for Treatment (P < 0.001) during the 112-day trial. Despite historic evidence of very high prevalence of lungworm infection in this region of southeastern Australia, iron chelate molluscicide treatment prior to lambs grazing the pasture had no demonstrable effect on the prevalence and severity of small lungworm infections, nor the productivity of lambs grazing these pastures. This study indicates that for a commercial sheep farm, additional molluscicide treatments of pastures after they are established, for the prevention of small lungworm infection, may not be warranted. Furthermore, requirements for more precisely monitoring snails are discussed.


Assuntos
Pneumopatias Parasitárias/veterinária , Moluscocidas/farmacologia , Doenças dos Ovinos/parasitologia , Animais , Pneumopatias Parasitárias/parasitologia , Pneumopatias Parasitárias/prevenção & controle , Moluscos/efeitos dos fármacos , Infecções por Nematoides/veterinária , Ovinos , Doenças dos Ovinos/prevenção & controle
11.
Zootaxa ; 4951(1): zootaxa.4951.1.1, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33903412

RESUMO

This article lists and comments on the primary and secondary types represented in the collection of the Bailey-Matthews National Shell Museum (BMSM), on Sanibel, Florida, USA. The collection includes 464 type specimens, of which 15 are holotypes, representing 149 taxa, of which 145 are species and four subspecies. The BMSM collection is fully catalogued and posted online via the Museum's website, in addition to iDigBio and GBIF. The publication of this annotated list intends to improve on the accessibility and promote this important group of name-bearing specimens, which includes, among other cases, types originating from orphaned collections and material poorly documented in the original descriptions. Eighty-two types were selected for illustration, and the photos of all BMSM types are available as part of the BMSM online collection catalog.


Assuntos
Moluscos/classificação , Museus , Exoesqueleto , Animais , Florida
12.
Zootaxa ; 4950(1): zootaxa.4950.1.4, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33903320

RESUMO

The species composition of the genus Connexochiton is revised. So far, six Recent species of the genus Connexochiton have been known: C. platynomenus, C. kaasi, C. crassus, C. bromleyi, C. moreirai and C. discernibilis After the present revision, the genus consists of Connexochiton platynomenus, C. kaasi, C. crassus, as well as three new species, C. costatus n. sp. from the Philippines, C. kermadeci n. sp. from New Zealand and C. solomonicus n. sp. from the Solomon Islands. Connexochiton discernibilis was assigned to the ischnochitonid genus Stenosemus (now Stenosemus discernibilis). Connexochiton bromleyi and C. moreirai are transferred back to the genus Ischnochiton. Principle features of the genus Connexochiton include: a distinctive shape of the valves with the hind edge of the intermediate valves noticeably turned down, which makes the lateral areas narrow and appearing strongly raised; tegmentum delicately sculptured by quincuncially arranged triangular granules that form an alveolate pattern; each granule has 9 to 11 aesthete pores; apophyses are connected medially by a short jugal plate, dorsal scales of the girdle are strongly bent, with short longitudinal ribs or spherules or both; head of the major lateral teeth of radula is unicuspid and sickle-shaped. An identification key for the species of the genus Connexochiton is provided.


Assuntos
Poliplacóforos , Animais , Moluscos , Poliplacóforos/classificação , Poliplacóforos/fisiologia
13.
J Med Chem ; 64(9): 6198-6208, 2021 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-33914531

RESUMO

In the marine environment, sessile cyanobacteria have developed chemical strategies for protection against grazers. In turn, herbivores have to circumvent these defenses and in certain cases even take advantage of them as shelter from their own predators. This is the case of Stylocheilus striatus, a sea hare that feeds on Anabaena torulosa, a cyanobacterium that produces toxic cyclic lipopeptides of the laxaphycin B family. S. striatus consumes the cyanobacterium without being affected by the toxicity of its compounds and also uses it as an invisibility cloak against predators. In this article, using different substrates analogous to laxaphycin B, we demonstrate the presence of an enzyme in the digestive gland of the mollusk that is able to biotransform laxaphycin B derivatives. The enzyme belongs to the poorly known family of d-peptidases that are suspected to be involved in antibiotic resistance.


Assuntos
Farmacorresistência Bacteriana/efeitos dos fármacos , Moluscos/metabolismo , Peptídeo Hidrolases/metabolismo , Peptídeos Cíclicos/metabolismo , Animais , Peptídeos Cíclicos/química , Peptídeos Cíclicos/toxicidade
14.
Mar Drugs ; 19(4)2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33808126

RESUMO

Hepatitis B virus (HBV) infection remains a major global health problem. It is therefore imperative to develop drugs for anti-hepatitis B with high-efficiency and low toxicity. Attracted by the observations and evidence that the symptoms of some patients from the Southern Fujian, China, suffering from hepatitis B were alleviated after daily eating an edible marine mollusk, Thais clavigera (Küster 1860) (TCK). Water-soluble polysaccharide from TCK (TCKP1) was isolated and characterized. The anti-HBV activity of TCKP1 and its regulatory pathway were investigated on both HepG2.2.15 cell line and HBV transgenic mice. The data obtained from in vitro studies showed that TCKP1 significantly enhanced the production of IFN-α, and reduced the level of HBV antigens and HBV DNA in the supernatants of HepG2.2.15 cells in a dose-dependent manner with low cytotoxicity. The result of the study on the HBV transgenic mice further revealed that TCKP1 significantly decreased the level of transaminases, HBsAg, HBeAg, and HBV DNA in the serum, as well as HBsAg, HBeAg, HBV DNA, and HBV RNA in the liver of HBV transgenic (HBV-Tg) mice. Furthermore, TCKP1 exhibited equivalent inhibitory effect with the positive control tenofovir alafenamide (TAF) on the markers above except for HBV DNA even in low dosage in a mouse model. However, the TCKP1 high-dose group displayed stronger inhibition of transaminases and liver HBsAg, HBeAg, and HBV RNA when compared with those of TAF. Meanwhile, inflammation of the liver was, by pathological observation, relieved in a dose-dependent manner after being treated with TCKP1. In addition, elevated levels of interleukin-12 (IL-12) and interferon γ (IFN-γ), and reduced level of interleukin-4 (IL-4) in the serum were observed, indicating that the anti-HBV effect of TCKP1 was achieved by potentiating immunocyte function and regulating the balance of Th1/Th2 cytokines.


Assuntos
Antivirais/farmacologia , Vírus da Hepatite B/efeitos dos fármacos , Hepatite B/tratamento farmacológico , Moluscos/metabolismo , Polissacarídeos/farmacologia , Animais , Antivirais/isolamento & purificação , Citocinas/metabolismo , Modelos Animais de Doenças , Células Hep G2 , Hepatite B/imunologia , Hepatite B/metabolismo , Hepatite B/virologia , Vírus da Hepatite B/genética , Vírus da Hepatite B/imunologia , Interações Hospedeiro-Patógeno , Humanos , Mediadores da Inflamação/metabolismo , Camundongos Transgênicos , Polissacarídeos/isolamento & purificação , Equilíbrio Th1-Th2/efeitos dos fármacos , Carga Viral
15.
Genes (Basel) ; 12(2)2021 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-33671839

RESUMO

Nitric Oxide (NO) plays a key role in the induction of larval metamorphosis in several invertebrate phyla. The inhibition of the NO synthase in Crepidula fornicata, a molluscan model for evolutionary, developmental, and ecological research, has been demonstrated to block the initiation of metamorphosis highlighting that endogenous NO is crucial in the control of this developmental and morphological process. Nitric Oxide Synthase contributes to the development of shell gland, digestive gland and kidney, being expressed in cells that presumably correspond to FMRF-amide, serotoninergic and catecolaminergic neurons. Here we identified a single Nos gene in embryonic and larval transcriptomes of C. fornicata and studied its localization during development, through whole-mount in situ hybridization, in order to compare its expression pattern with that of other marine invertebrate animal models.


Assuntos
Evolução Biológica , Gastrópodes/genética , Moluscos/genética , Óxido Nítrico Sintase/genética , Animais , Gastrópodes/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento/genética , Larva/genética , Larva/crescimento & desenvolvimento , Metamorfose Biológica/genética , Moluscos/crescimento & desenvolvimento , Óxido Nítrico/genética
16.
Toxins (Basel) ; 13(2)2021 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-33671640

RESUMO

Shellfish toxin monitoring programs often use mussels as the sentinel species to represent risk in other bivalve shellfish species. Studies have examined accumulation and depuration rates in various species, but little information is available to compare multiple species from the same harvest area. A 2-year research project was performed to validate the use of mussels as the sentinel species to represent other relevant eastern Canadian shellfish species (clams, scallops, and oysters). Samples were collected simultaneously from Deadmans Harbour, NB, and were tested for paralytic shellfish toxins (PSTs) and amnesic shellfish toxin (AST). Phytoplankton was also monitored at this site. Scallops accumulated PSTs and AST sooner, at higher concentrations, and retained toxins longer than mussels. Data from monitoring program samples in Mahone Bay, NS, are presented as a real-world validation of findings. Simultaneous sampling of mussels and scallops showed significant differences between shellfish toxin results in these species. These data suggest more consideration should be given to situations where multiple species are present, especially scallops.


Assuntos
Monitoramento Biológico , Toxinas Marinhas/metabolismo , Moluscos/metabolismo , Espécies Sentinelas/metabolismo , Intoxicação por Frutos do Mar , Frutos do Mar/análise , Animais , Oceano Atlântico , Biotransformação , Avaliação de Programas e Projetos de Saúde , Reprodutibilidade dos Testes , Especificidade da Espécie , Fatores de Tempo
17.
Zootaxa ; 4933(1): zootaxa.4933.1.3, 2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33756804

RESUMO

So far, of the 292 known species of solenogasters (Mollusca, Aplacophora), 62 belong to the clade Pholidoskepia Salvini-Plawen, 1978. Of these, only two have an abyssal distribution (3500-6000 m depth). Among Pholidoskepia, Dondersiidae Simroth, 1893 is the most diverse family. This study contributes to the knowledge of this family with the description of one new genus and six new species from the abyssal South Atlantic Ocean: Dondersia ? foraminosa sp. n., Nematomenia divae sp. n., Nematomenia brasiliensis sp. n., Nematomenia ? guineana sp. n., Helluoherpia vieiralaneroi sp. n. and Inopinatamenia (gen. n.) calamitosa sp. n. Specimens were collected during DIVA (Latitudinal Gradients of Deep-Sea BioDIVersity in the Atlantic Ocean) expeditions in the Guinea (DIVA 2 Me 63/2, 2005) and Brazil (DIVA 3 Me 79/1, 2008) Basins. Specimens were characterized based primarily on the sclerites and internal anatomy, which was studied using histology. The importance of the radula and mantle sclerites for taxonomy is emphasized. Amended diagnoses for the family and some genera within this family are provided. This contribution increases the described diversity of Dondersiidae to ten genera and 38 species and highlights the need for more study of solenogasters in the deep sea.


Assuntos
Biodiversidade , Moluscos , Animais , Filogenia
18.
BMC Ecol Evol ; 21(1): 36, 2021 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-33663373

RESUMO

BACKGROUND: Hemocyanin is the oxygen transporter of most molluscs. Since the oxygen affinity of hemocyanin is strongly temperature-dependent, this essential protein needs to be well-adapted to the environment. In Tectipleura, a very diverse group of gastropods with > 27,000 species living in all kinds of habitats, several hemocyanin genes have already been analyzed. Multiple independent duplications of this gene have been identified and may represent potential adaptations to different environments and lifestyles. The aim of this study is to further explore the evolution of these genes by analyzing their exon-intron architectures. RESULTS: We have reconstructed the gene architectures of ten hemocyanin genes from four Tectipleura species: Aplysia californica, Lymnaea stagnalis, Cornu aspersum and Helix pomatia. Their hemocyanin genes each contain 53 introns, significantly more than in the hemocyanin genes of Cephalopoda (9-11), Vetigastropoda (15) and Caenogastropoda (28-33). The gene structures of Tectipleura hemocyanins are identical in terms of intron number and location, with the exception of one out of two hemocyanin genes of L. stagnalis that comprises one additional intron. We found that gene structures that differ between molluscan lineages most probably evolved more recently through independent intron gains. CONCLUSIONS: The strict conservation of the large number of introns in Tectipleura hemocyanin genes over 200 million years suggests the influence of a selective pressure on this gene structure. While we could not identify conserved sequence motifs within these introns, it may be simply the great number of introns that offers increased possibilities of gene regulation relative to hemocyanin genes with less introns and thus may have facilitated habitat shifts and speciation events. This hypothesis is supported by the relatively high number of introns within the hemocyanin genes of Pomacea canaliculata that has evolved independently of the Tectipleura. Pomacea canaliculata belongs to the Caenogastropoda, the sister group of Heterobranchia (that encompass Tectipleura) which is also very diverse and comprises species living in different habitats. Our findings provide a hint to some of the molecular mechanisms that may have supported the spectacular radiation of one of Metazoa's most species rich groups.


Assuntos
Gastrópodes , Hemocianinas , Animais , Evolução Molecular , Gastrópodes/genética , Hemocianinas/genética , Íntrons/genética , Moluscos/genética
19.
Environ Pollut ; 279: 116919, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33744630

RESUMO

Gymnodimine A has been found in mollusks obtained along the whole northern coast of Spain from April 2017 to December 2019. This is the first time that this toxin is detected in mollusks from the Atlantic coast of Europe. The prevalence of the toxin was, in general, low, being detected on average in approximately 6% of the obtained samples (122 out of 1900). The concentrations recorded were also, in general, low, with a median of 1.3 µg kg-1, and a maximum value of 23.93 µg kg-1. The maxima of prevalence and concentration were not geographically coincident, taking place the first at the easternmost part of the sampled area and the second at the westernmost part. In most cases (>94%), gymnodimine A and 13-desmethyl spirolide C were concurrently detected, suggesting that Alexandrium ostenfeldii could be the responsible producer species. The existence of cases in which gymnodimine A was detected alone suggests also that a Karenia species could also be involved. The geographical heterogeneity of the distribution suggests that blooms of the producer species are mostly local. Not all bivalves are equally affected, clams being less affected than mussels, oysters, and razor clams. Due to their relatively low toxicity, and their low prevalence and concentration, it seems that these toxins do not pose an important risk for the mollusk consumers in the area.


Assuntos
Toxinas Marinhas , Moluscos , Animais , Europa (Continente) , Compostos Heterocíclicos de 4 ou mais Anéis , Iminas , Prevalência , Espanha
20.
Gene ; 785: 145604, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33766707

RESUMO

The basic helix-loop-helix (bHLH) transcription factors form a large superfamily that plays an important role in numerous physiological processes, including development and response to environmental stresses. In this study, the distribution of bHLH genes in nine molluscs was systematically investigated (including five bivalves, three gastropods and one cephalopod). Finally, 53-85 bHLH genes were identified from each genome and classified into corresponding families by using phylogenetic analysis. The results of gene structure and conserved motif analysis illustrated the hereditary conservation of bHLH transcription factors during evolution but showed low similarity in group C. Through transcription profile analysis of C. gigas and T. granosa, we found a important role of bHLH genes in responding to multiple external challenges and development; meanwhile, they also exhibited tissue-specific expression. Interestingly, we were also surprised to find different bHLH genes from the same group generally possess similar patterns expression that tends to simultaneously present high or lower expression of multiple challenges and different tissues in this study. In summary, this study lays the foundation for further investigation of the biological functions and evolution of molluscan bHLH genes.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Moluscos/genética , Animais , Feminino , Genoma , Masculino
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