Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 6.325
Filtrar
1.
An Acad Bras Cienc ; 93(2): e20190580, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33681876

RESUMO

We investigated the effects of eyestalk ablation and cheliped autotomy in inducing molting in Callinectes ornatus. The specimens in intermolt stage were divided into two size classes: 1 (30-50 mm) and 2 (51-70 mm) and were further divided into four experimental groups. In the CA group (Cheliped Autotomy, n=76), crabs were submitted to cheliped autotomy; in the UA group (Unilateral Ablation, n=66) and BA group (Bilateral Ablation, n=66) to unilateral and bilateral eyestalk ablation, respectively. The C group (Control, n=70) was used as control. The animals were individually kept in tanks interconnected to a recirculation system for 30 days. The highest frequency of premolt was recorded in the BA group (32%), followed by the CA group (16%). The premolt frequency of class 1 (28%) was significantly higher (p<0.05) than of class 2 (8%). The mean time until molt in the BA group was significantly lower (p <0.05) than other groups tested. The highest mortality rates were 55% and 25% in crabs from the BA and CA groups, respectively. The results indicate bilateral eyestalk ablation and cheliped autotomy are potentially capable of inducing molt in C. ornatus, but these techniques have limited efficiency for the commercial application of large-scale soft-shell crab.


Assuntos
Braquiúros , Muda , Animais
2.
Zootaxa ; 4938(3): zootaxa.4938.3.3, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33756974

RESUMO

Tritodynamia bengalensis n. sp. is described on the basis of a male specimen dredged from the shallow coastal waters of West Bengal state, India. The new species is morphologically similar to T. bidentata Yang Tang, 2005 and T. serratipes Anker Ng, 2014, but can be distinguished by the carapace shape, dentition of the pollex, relative length of the dactylus of the third maxilliped, proportions of the propodus of the third pereopod, and structure of the male left gonopod. This is the first record of the genus Tritodynamia from India.


Assuntos
Braquiúros , Exoesqueleto , Animais , Índia , Masculino
3.
Zootaxa ; 4948(2): zootaxa.4948.2.3, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33757025

RESUMO

The taxonomic status of the widely distributed West and Central African freshwater crab Sudanonautes granulatus (Balss, 1929) sensu lato is revised in the light of improved morphological evidence which indicates that this taxon is a complex comprising at least 4 species: Sudanonautes granulatus (Balss, 1929) sensu stricto from Togo, S. koudougou n. sp. from Côte d'Ivoire, S. umaji n. sp. from Nigeria, and S. tiko from Cameroon, Nigeria, and Bioko. Diagnoses, illustrations and distribution maps are provided for these species and they are compared with congeners from West and Central Africa.


Assuntos
Braquiúros , Animais , Costa do Marfim , Água Doce , Nigéria
4.
Zootaxa ; 4903(2): zootaxa.4903.2.8, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33757101

RESUMO

A new species of pseudothelphusid crab of the tribe Kingsleyini Ortmann, 1897, from the southern Amazon region in the state of Rondônia, Brazil, is described and illustrated. Fredius avilai n. sp. can be readily distinguished from its congeners by the following characters of the male first gonopod: mesial lobe elongated, convoluted, proximal portion directed laterally, distal portion sharply recurved in abdominal direction; marginal process rounded, not projected over distal opening of spermatic channel, merging with distal portion of abdominal surface after a shallow depression; lateral suture well demarcated along mesoabdominal surface of stem, distal portion directed inwards. The assignment of the new species to the genus Fredius Pretzmann, 1967 and its affinities with another closed related species are discussed.


Assuntos
Ascaridídios , Braquiúros , Animais , Brasil , Masculino
5.
Mar Pollut Bull ; 165: 112184, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33621905

RESUMO

The occurrence of 27 antibiotics (18 sulfonamides and 9 quinolones) in 92 samples of cultured Chinese mitten crab (Eriocheir sinensis) from three provinces (Anhui, Jiangsu and Liaoning) was investigated. These 21 antibiotics were detected at least once in crabs from these provinces with detection frequencies of 3.70-90.91%. Sulfonamides were detected in 53.7% of the samples at concentrations of 0.1-10 µg/kg in Jiangsu, while quinolones were detected with 90.9% of samples containing concentrations of 1-100 µg/kg in Liaoning province. Enroflxacin, ciprofloxacin, sulfaquinoxaline, sulfameter, sulfadoxine, and sulfamethoxazole were the mainly used antibiotics and enroflxacin were present at a high concentration (>100 µg/kg). Dietary assessments showed that residual antibiotics in crabs from China were far below the maximum residue limit (MRL) of total sulfonamides and quinolones, and there was almost no risk associated with crab consumption. These results will provide meaningful indications for the safety of crab consumption.


Assuntos
Braquiúros , Quinolonas , Animais , China , Sulfanilamida , Sulfonamidas
6.
Food Chem ; 350: 129196, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33607409

RESUMO

Histamine poisoning from seafood is a significant public health and safety concern. To detect histamine sensitively and accurately, a novel competitive sandwich immunoassay using a modified biotin-streptavidin system coupling with polylysine was developed. Using this strategy, a sandwich ELISA with an IC50 value of 112.8 ng mL-1 and a broad linear range of 11.7-1500 ng mL-1 with a correlation coefficient of 0.9942 was validated. Without any sample derivatization procedure, the recovery of histamine ranged from 80.19% to 108.3% with a coefficient of variation of 1.43-11.7% in tuna, prawn and crab. The sandwich ELISA had a detectionlimit of 5.86 ng mL-1, which was 15-fold lower than an indirect competitive ELISA (ic-ELISA). This simple, sensitive and accurate method can be applied to detect histamine in routine seafood samples.


Assuntos
Biotina/metabolismo , Braquiúros/química , Decápodes/química , Ensaio de Imunoadsorção Enzimática/métodos , Histamina/análise , Estreptavidina/metabolismo , Atum , Animais , Análise de Alimentos , Limite de Detecção , Alimentos Marinhos/análise
7.
Mar Pollut Bull ; 164: 112089, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33524828

RESUMO

Based on our discussions with fishermen and analysis of catches from professional fishing, this work confirms the presence of the American blue crab Callinectes sapidus in the southwest Mediterranean and highlights its invasion of Mellah lagoon in Algeria. The number and frequency of occurrence of this species in fishing gear (up to 10 individuals per fyke net), the presence of juveniles and ovigerous females as well as its presence in the local market, show that it is well established. The possible impact of C. sapidus on the local environment and native species, and the prospects for its fishing exploitation are discussed in the light of the current knowledge.


Assuntos
Braquiúros , Argélia , Animais , Feminino , Humanos , Estados Unidos
8.
Ecotoxicol Environ Saf ; 213: 112004, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33581488

RESUMO

Salinity is one of the important factors affecting the physiological state of crustaceans in marine environments. Lipid plays major roles in energy supply and is main sources of essential fatty acids for membrane integrity, which is critical in adaptations to changes in salinity. Here we evaluated the effects of salinity (medium, 23 ppt and low, 4 ppt) and dietary lipid source (fish oil, FO and soybean oil, SO) on intestinal health of the marine crustacean mud crab Scylla paramamosain. The results indicated that low salinity and dietary SO (LSO group) significantly affected intestinal histomorphology, with a significant decrease of intestinal fold height and width as well as down-regulation of intestinal mRNA levels of tight junction genes compared to crab reared at medium salinity and fed FO diets (MFO group). Crabs reared at low salinity and fed SO showed an increased inflammatory response in intestine, which stimulated a physiological detoxification response together with apoptosis compared to crab in the MFO group. Low salinity and SO diets also could be responsible for multiply the pathogenic bacteria of Photobacterium and inhibit the beneficial bacteria of Firmicutes and Rhodobacteraceae in intestine, and act on a crucial impact on the development of intestinal microbial barrier disorders. The results of microbial function predictive analysis also support these inferences. The findings of the present study demonstrated that soybean oil as the main dietary lipid source could exacerbate the adverse effects of low salinity on intestinal health of mud crab, and provided evidence suggesting that dietary lipid source and fatty acid composition may play vital roles in intestinal health and the process of adaptation to environmental salinity in marine crustaceans.


Assuntos
Braquiúros/fisiologia , Exposição Dietética/estatística & dados numéricos , Óleo de Soja , Adaptação Fisiológica/genética , Animais , Braquiúros/genética , Dieta , Intestinos , RNA Mensageiro/genética , Salinidade
9.
Chemosphere ; 271: 129444, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33445026

RESUMO

In this study, we analyzed biomarkers and heavy metals in Ucides cordatus specimens caught in mangrove areas [A1 = reference (low impact area); A2, A3 and A4 = port complex (potentially impacted area)] of the Amazonian northern coast of Brazil. Sediments and crab muscles sampled from the potentially impacted mangroves showed high levels of metals. Additionally, catalase and glutathione S-transferase enzymes in the gills and hepatopancreas of the collected crabs were elevated in crabs from A2, A3 and A4 relative to those from A1. The histological characteristics of the gills and hepatopancreas differed in crabs collected from A2, A3 and A4 compared with those collected from A1. The crabs were larger and heavier in the rainy season in A1 and A3 and heavier in the dry season in A4. Heavy metal analyses of sediments, crab muscles and biological responses indicated that the animals are subjected to stress levels differentiated in the mangroves due to a gradient (A4>A3>A2>A1) of anthropogenic pressure in São Marcos Bay. In conclusion, the analyses of metals in the sediment and in the muscles of crabs, as well as the biochemical biomarker and histological analyses, suggest that crabs from mangroves in the port complex region are subject to pollutants that compromise their health.


Assuntos
Braquiúros , Metais Pesados , Poluentes Químicos da Água , Animais , Bioacumulação , Biomarcadores , Brasil , Monitoramento Ambiental , Metais Pesados/análise , Poluentes Químicos da Água/análise
10.
Mar Environ Res ; 165: 105238, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33486259

RESUMO

Artificial light at night (ALAN) is one of the most extensive human geographic disturbances to wildlife. ALAN can have ecological and evolutionary effects on individual organisms, which in turn can affect populations, communities and ecosystems. Although understanding of the effects of ALAN on the ecology and biology of organisms has increased in recent years, most of these advances are in terrestrial environments, but scarce in marine habitats, especially in ecologically important transition areas such as saltmarshes. Here, we study the effects of ALAN on the behavioural budget (i.e. the proportion of time spent performing feeding, burrow maintenance and concealment) of the South American intertidal crab Neohelice granulata, which is an ecosystem engineer of coastal salt marshes. Moreover, we compared the impact of a gradient of ALAN between two different saltmarshes with contrasting environmental characteristics. Our results showed a relationship between ALAN and the behavioural budget. In particular, we showed that an increase in ALAN drove an increase in time spent maintaining burrows at the expense of time spent concealed in the burrow or feeding outside it. Such effects showed slightly different patterns in the two saltmarshes, possibly related to the reproductive value of burrows for mating and to predation risk. Considering the ecosystem role of N. granulata, we argue that the different effect of ALAN on its behavioural budget could have ecosystem effects that differ between the two saltmarshes studied here.


Assuntos
Braquiúros , Ecossistema , Animais , Humanos , Luz , Comportamento Predatório , Reprodução , Alimentos Marinhos
11.
Dis Aquat Organ ; 143: 13-18, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33506811

RESUMO

Neoplasia is rarely reported in decapod crustaceans, and sarcoma has not been previously reported in any crab species. A California king crab Paralithodes californiensis with a recent history of autotomy (4 legs lost) and anorexia was found dead. Grossly, the crab had a pigmented ulcer on the right cheliped merus. Necropsy tissue samples were placed in 10% neutral buffered formalin and processed routinely for histology. Both histochemical (i.e. Brown and Brenn Gram, Fite-Faraco acid fast, Fontana-Masson, Giemsa, hematoxylin and eosin, Masson's trichrome, periodic acid-Schiff [PAS], phosphotungstic acid-hematoxylin, and von Kossa) and immunohistochemical (i.e. cytokeratin, vimentin, and lysozyme) stains were performed. The body wall (presumably of the right cheliped merus) was ulcerated and subtended by a densely cellular, unencapsulated, invasive neoplasm composed of spindle cells arranged in intersecting streams and bundles embedded in a small to moderate amount of fibromatous stroma. Neoplastic cells were oval to elongate with fibrillar, pale eosinophilic cytoplasm that occasionally contained moderate numbers of small, spherical, brightly eosinophilic granules that were highlighted with PAS and Giemsa stains. Neoplastic cells had mild atypia and no evident mitoses. Immunohistochemical stains were noncontributory. This neoplasm is consistent with hemocytic sarcoma of semi-granulocytic origin. Decapod crustaceans have 3 types of hemocytes: hyalinocytes, granulocytes, and semi-granulocytes. Neoplastic cells had PAS- and Giemsa-positive granules, which are present in both semi-granulocytes and granulocytes. Semi-granulocytes can elongate and are associated with deposition of extracellular matrix during some immune responses. Neoplastic cells were elongate and associated with deposition of matrix. These findings suggest neoplastic cells were of semi-granulocytic origin.


Assuntos
Anomuros , Braquiúros , Sarcoma , Animais , California , Hemócitos , Sarcoma/veterinária
12.
Gene ; 774: 145423, 2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33434625

RESUMO

Sox9 gene, a crucial member of the Sox gene family, is present in various organisms and involved in many physiological processes, especially in sex determination and gonad development. In this study, we reported a sox9 gene (designated as Spsox9) from Scylla paramamosain through analyzing published gonad transcriptome data. Meanwhile, the accuracy was validated by PCR technology, and the 3' sequences were cloned with 3' RACE technology. The full-length cDNA of Spsox9 is 2843 bp, consisting of a 243 bp 5' UTR, an 1124 bp 3' UTR, and a 1476 bp ORF encoding 491 amino acids. Furthermore, to better understand its conservation among crustacean species, the sox9 gene ortholog was identified in several other crustaceans species with their published transcriptome data, respectively. All of the Sox9 proteins identified in the current study had the common feature of Sox proteins (HMG domain) and were highly conserved among analyzed crustacean species. In all examined tissues, the Spsox9 was mainly expressed in the gonad (testis and ovary), eyestalk, and cerebral ganglion. During embryo development, Spsox9 was highly expressed in 5 pairs of appendages, 7 pairs of appendages, and eye-pigment formation stage. During ovary development, the expression level of Spsox9 remained stable in the first 4 stages (O1-O4) and decreased in the tertiary vitellogenesis (O5) stage. During testis development, the expression level of Spsox9 was highest in the spermatid stage (T2) and was significantly different from that in the spermatocyte stage (T1) and mature sperm stage (T3) (p < 0.05). In addition, Spsox9 exhibited a sex-biased expression pattern in T1 and O1. These present results indicated that the Spsox9 gene might play crucial roles in the gonad and embryo development of mud crab.


Assuntos
Proteínas de Artrópodes/genética , Braquiúros/genética , Fatores de Transcrição SOX9/genética , Sequência de Aminoácidos , Animais , Braquiúros/embriologia , Clonagem Molecular , Sequência Conservada , DNA Complementar , Feminino , Perfilação da Expressão Gênica , Gônadas/embriologia , Humanos , Masculino , Homologia de Sequência de Aminoácidos , Caracteres Sexuais , Especificidade da Espécie , Vitelogeninas/genética
13.
Sci Total Environ ; 766: 144254, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33421778

RESUMO

Consumers are often overlooked as key drivers of vegetation structure and ecosystem functioning in coastal wetlands. This oversight is particularly apparent in Asia, where much of the variation in coastal wetland plant growth and composition is attributed to physical stress gradients. To address this knowledge gap and quantify the relative importance of consumers in Asian coastal wetlands across temporal variation in environmental stress, we conducted a two-year experiment spanning relatively spring wet (2018) and spring dry (2019) years in which we manipulated the presence of the numerically dominant herbivorous crab, Helice tientsinensis, and evaluated its effects on Phragmites australis growth and structure in a Yellow River Delta salt marsh. In spring wetter 2018, Phragmites biomass and stem density were 75% and 34% higher in Crab Exclusion relative to Ambient Crab plots. In 2019 which experienced spring drought and elevated soil salinity, Phragmites biomass and stem density remained similarly high relative to 2018 in Crab Exclusion plots, but fell further, to only 16% and 39% of levels of 2018 observed in Ambient Crab plots. Phragmites' inflorescences density was also significantly reduced in Ambient Crab than Crab Exclusion plots in 2019. Together, these results highlight the significant role that crab herbivores can play in regulating Phragmites in Yellow River Delta salt marshes and suggest that the magnitude of their top-down control may be amplified, although in a non-additive manner, with spring drought stress in the region.


Assuntos
Braquiúros , Áreas Alagadas , Animais , Ásia , Secas , Ecossistema , Herbivoria , Poaceae , Rios
14.
Mar Pollut Bull ; 163: 111971, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33503565

RESUMO

This study investigates the concentration of heavy metals in the macroalgae, seagrasses, mangroves, and crabs collected from Hare Island, Gulf of Mannar Marine Biosphere Reserve. The concentration of heavy metals ranged between 0.06 (Hg)-259 (Fe) µg/g in macroalgae, 0.09 (Pb)-377 (Fe) µg/g in seagrasses, 0.112 (Cd)-122 (Fe) µg/g in mangroves, and 0.11 (Cd) -240 (Fe) µg/g in crabs. The levels of heavy metals in the analyzed samples were found below the maximum residual limits (MRLs) prescribed by various National and International agencies. The result suggests that exposure to the analyzed metals through macroalgae consumption does not cause potential health risks to consumers (target hazard quotient (THQ), estimated exposure dose (EED), and hazard index (HI) <1). Hence, this study concludes that macroalgae that grow in the Gulf of Mannar regions are safe for human consumption and are suitable to prepare food supplements and bioceutical products.


Assuntos
Braquiúros , Lebres , Metais Pesados , Alga Marinha , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Contaminação de Alimentos/análise , Humanos , Índia , Ilhas , Metais Pesados/análise , Medição de Risco , Poluentes Químicos da Água/análise
15.
Bull Environ Contam Toxicol ; 106(4): 583-588, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33507346

RESUMO

This study was aimed at evaluating the possible interference of formulated glyphosate to the endocrine control of ovarian growth exerted by progesterone, in the estuarine crab Neohelice granulata. The addition of Roundup Ultramax® (0.2 mg/L of glyphosate in the incubation medium) was able to potentiate the stimulating effect of progesterone on total vitellogenic protein (Vg) content of ovarian pieces from crabs. Moreover, the sole addition of mifepristone (antagonist of progesterone receptors) was able to produce a decrement of the Vg content, which was not reverted by the addition of Roundup. A similar result was confirmed by means of histological analysis, which showed that mifepristone, both alone and in combination with Roundup, inhibited ovarian maturation, while Roundup alone increased it, in terms of a higher proportion of vitellogenic oocytes. We conclude that Roundup could stimulate the progesterone secretion exerted by the ovary and/or could act as a partial agonist of this hormone in the same tissue.


Assuntos
Braquiúros , Herbicidas , Animais , Feminino , Glicina/análogos & derivados , Glicina/toxicidade , Ovário , Progesterona
16.
Chemosphere ; 271: 129479, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33460905

RESUMO

Crabs are an indispensable component of the benthic ecosystem and represent a type of seafood that is easily obtained and frequently eaten by humans. However, little is known about microplastic (MP) accumulation in different tissues of crabs in important fishing areas. In this study, the abundances and characteristics of MPs in different tissues of four species of wild crabs (Portunus trituberculatus, Charybdis japonica, Dorippe japonica, and Matuta planipes) were investigated across 9 sites at three important fishing grounds (Haizhou Bay, Lvsi and Yangtze River Estuary fishing grounds) in China. Crabs from all sites were found to contain MPs, with a total detection rate of 89.34%. The MP abundance in crabs from all sites ranged from 2.00 ± 2.00 to 9.81 ± 8.08 items/individual and 0.80 ± 1.09 to 22.71 ± 24.56 items/g wet weight. The abundance of MPs exponentially increased with decreasing MP size. The MPs were dominated by fibers in terms of shape, black-gray and blue-green in terms of color and cellophane in terms of composition. MPs were found in the gills and guts of the crabs, but not in the muscles. The abundance and size of the MPs in the guts were significantly higher than those in the gills, but there was no significant difference in color or shape. In addition, crab eating patterns have a significant impact on the abundance of MPs in different species. The abundance of MPs in the saprophytic crabs was significantly higher than that in the predatory crabs. MP contamination in crabs is worthy of attention for human health and the stability of marine ecosystems.


Assuntos
Braquiúros , Poluentes Químicos da Água , Animais , China , Ecossistema , Monitoramento Ambiental , Humanos , Microplásticos , Plásticos , Poluentes Químicos da Água/análise
17.
Sci Total Environ ; 769: 144854, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33486186

RESUMO

Restoration has been increasingly adopted to halt trends in coastal wetland loss globally. Existing restoration often assumes that once abiotic stress is relieved, disturbances are prevented, and invasive species are eradicated, coastal wetlands will recover if propagules of native species are supplied either through natural dispersal or planting. Whether other factors including consumers can help explain the often suboptimal performance of existing restoration remains poorly understood. In a series of field experiments in the Yangtze estuary, we examined the relative importance of abiotic stress and crab grazing in regulating the recovery of the native foundation plant species Scirpus mariqueter in salt marsh areas where exotic cordgrass was successfully eradicated. We found that grazing by herbivorous crabs, rather than abiotic stress, was the primary obstacle restricting the recovery of planted Scirpus. This negative effect of crab grazing varied predictably across elevation and was strongest at low elevations where abiotic conditions were positive for Scirpus. These findings highlight that i) measures to control crab grazing are needed to enhance the success of Scirpus restoration, even in areas where abiotic conditions are set to be optimal, and ii) restoration measures purely focused on reducing abiotic stress could be ineffective or suboptimal in field conditions, likely jeopardizing restoration investment and success. Since top-down control of foundation plant species is common in many coastal wetlands and can be especially important in degraded systems where herbivores are abundant, we urge that future coastal wetland restoration assesses for the impacts of grazers and, when present, apply intervention measures.


Assuntos
Braquiúros , Áreas Alagadas , Animais , Estuários , Herbivoria , Poaceae
18.
Arch Virol ; 166(3): 891-896, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33454862

RESUMO

An active prophage, Vibrio phage ValM-yong1, was isolated from pathogenic Vibrio alginolyticus by mitomycin C induction. This phage is a member of the family Myoviridae and contains a head approximately 90 nm in diameter and a retractable tail approximately 250 nm in length. The genome of the phage is 33,851 bp in length with a G+C content of 45.6%. The noteworthy features of Vibrio phage ValM-yong1 are its flower-like head and genomic mosaicism. Here, we focus on presenting the genomic characterization of the virus.


Assuntos
Genoma Viral/genética , Myoviridae/genética , Vibrio alginolyticus/virologia , Animais , Composição de Bases , Sequência de Bases , Braquiúros/microbiologia , Prófagos/genética , Sequenciamento Completo do Genoma
19.
Sci Total Environ ; 754: 142099, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32911152

RESUMO

Microplastics are considered detrimental to aquatic organisms due to their potential accumulation along food chains. Thus, it is puzzling why some of them appear unaffected by microplastics. Here, we assessed the contribution of water filtration and food consumption to microplastic accumulation in a predatory marine crab (Charybdis japonica) and examined the associated impacts of microplastics (particle size: 5 µm) following ingestion for one week. Results showed that water filtration and food consumption contributed similarly to the accumulation of microplastics, which were distributed among organs in this order: hepatopancreas > guts > gills > muscles. Yet, biomagnification (i.e. accumulation through consumption of microplastic-contaminated mussels) did not occur possibly due to egestion of microplastics. The crabs upregulated detoxification capacity (EROD) and antioxidant defence (GST) in response to the microplastics accumulated in their tissues. However, these defence mechanisms collapsed when the microplastic concentration in hepatopancreas exceeded ~3 mg g-1, leading to severe hepatic injury (elevated AST and ALT) and impaired neural activity (reduced AChE). Our results suggest that marine organisms have an innate capacity to counter the acute effects of microplastics, but there is a limit beyond which the defence mechanisms fail and hence physiological functions are impaired. As microplastic pollution will deteriorate in the future, the fitness and survival of marine organisms may be undermined by microplastics, affecting the stability and functioning of marine ecosystems.


Assuntos
Braquiúros , Poluentes Químicos da Água , Animais , Organismos Aquáticos , Ecossistema , Monitoramento Ambiental , Microplásticos , Plásticos/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
20.
Gene ; 771: 145361, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33338508

RESUMO

Hypoxia is a critical, but frequently overlooked problem, which commonly exists in Chinese mitten crab rearing. However, little information is available on the molecular mechanisms of the detrimental effects of hypoxia in this species. In the present study, crabs were subjected to acute hypoxia stress (DO 1.0 mg/L), followed by reoxygenation (DO 6.8 mg/L). Hepatopancreas from five groups of crabs (three to four crabs per group), including normoxia, hypoxia for one and six hours, and reoxygenation for one and 12 h, were used for transcriptome sequencing. The pooled total RNA of all samples were utilized to reconstruct a reference transcriptome with PacBio RS II sequencing, obtaining 49.19 G clean data, with a mean length of 2,180 bp. Seventeen cDNA libraries were constructed and sequenced to identify differentially expressed genes (DEGs) among the different samples (FDR < 0.05 and |log2 fold change| ≥1). A total of 103 and 251 DEGs were identified when exposed to hypoxia for one and six hours, respectively. Totally 462 and 673 DEGs were identified during reoxygenation at 1 and 12 h, respectively. Among these DEGs, two transcripts with complete ORFs were identified to encode hypoxia-inducible factor 1 (Es-Hif-1α/ß), which is a transcriptional activator of various genes correlated to the cellular adaptive responses to hypoxia. Es-Hif-1a/ß expressions were significantly upregulated when exposed to hypoxia treatment, and no significant difference was observed for Es-Hif-1α between hypoxic treatment for 6 h and reoxygenation. The significant KEGG enrichment revealed that the DEGs under hypoxia were mainly enriched in "PPAR signaling pathway", "Gap junction" and "Phototransduction-fly". Compared with crabs in normoxia, even with 12 h of reoxygenation, the hepatopancreas transcriptome under hypoxia remained severely affected, implying its adverse effect on growth and development, or increased susceptibility to diseases.


Assuntos
Translocador Nuclear Receptor Aril Hidrocarboneto/genética , Braquiúros/genética , Perfilação da Expressão Gênica/veterinária , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Animais , Proteínas de Artrópodes/genética , Hipóxia Celular , Regulação da Expressão Gênica , Hepatopâncreas/química , Análise de Sequência de RNA/veterinária , Estresse Fisiológico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...