Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.470
Filtrar
1.
Mar Pollut Bull ; 150: 110743, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31910517

RESUMO

Copper (Cu) is an essential metal capable to alter many metabolic and physiological processes in animal species, depending on the environmental concentration and salinity. The present study evaluated the effects of Cu exposure on the metabolism of the blue crab Callinectes sapidus under different osmotic situations. Crabs were acclimated at two different salinities conditions (30 and 2). Subsequently, they were exposed to Cu during 96 h at each salinity and under hypo-osmotic shock. Results demonstrated that Cu exposure increased whole-body oxygen consumption. In addition, the activity of LDH decreased while citrate synthase increased in anterior gills from animals submitted to hypo-osmotic shock. This scenario indicates extra stress caused by sudden environmental osmotic changes, as commonly observed in estuarine environments, when combined with copper exposure. Therefore, the activity of LDH and citrate synthase enzymes might be sensitive indicators for aquatic toxicology studies approaching Cu contamination in estuarine environments.


Assuntos
Braquiúros/fisiologia , Cobre/toxicidade , Metabolismo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Braquiúros/metabolismo , Brânquias , Pressão Osmótica/fisiologia , Salinidade
2.
Appl Microbiol Biotechnol ; 104(5): 2229-2241, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31915903

RESUMO

The aquatic microbial community is sensitive to environmental change; however, the impacts of those changes combined with disease outbreaks affecting S. paramamosain are unknown. Thus, from March to October, we explored the interaction between aquacultural environmental conditions and microbial composition and function in open-air aquaculture ponds containing S. paramamosain in Southern China. The microbial community structure was significantly positively correlated with microbial community function. The environment variables such as temperature and salinity during May and June changed more quickly compared with other periods, resulting changes in the structure and function of the microbial community affected S. paramamosain survivability, with higher crab mortality observed from May to June compared with other periods. These included changes in the relative abundance of Microtrichales, Synechococcales, Rhodobacterales, Chitinophagales, and SAR11_clade, and corresponding functions associated with glycolysis and/or gluconeogenesis, porphyrin and chlorophyll metabolism, photosynthetic proteins, and transcription factors. These changes could impact S. paramamosain mortality and be used to evaluate the health status of the ponds. Though the environment variables during July~October changed slowly comparing to May and June, the ponds microflora changed which benefit S. paramamosain survivability with correspondingly low S. paramamosain mortality. Therefore, rapid environmental change alters the structure and function of the aquatic microflora, increasing S. paramamosain mortality.


Assuntos
Braquiúros/fisiologia , Microbiota , Tanques/microbiologia , Microbiologia da Água , Animais , Aquicultura , China , Monitoramento Ambiental , Microbiota/genética , Nutrientes/análise , Tanques/química , Salinidade , Estações do Ano , Temperatura
3.
Aquat Toxicol ; 218: 105358, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31805486

RESUMO

Mangroves are tidal wetlands that are often under strong anthropogenic pressures, despite the numerous ecosystem services they provide. Pollution from urban runoffs is one such threats, yet some mangroves are used as a bioremediation tool for wastewater (WW) treatment. This practice can impact mangrove crabs, which are key engineer species of the ecosystem. Using an experimental area with controlled WW releases, this study aimed to determine from an ecological and ecotoxicological perspective, the effects of WW on the red mangrove crab Neosarmatium africanum. Burrow density and salinity levels (used as a proxy of WW dispersion) were recorded, and a 3-week caging experiment was performed. Hemolymph osmolality, gill Na+/K+-ATPase (NKA) activity and gill redox balance were assessed in anterior and posterior gills of N. africanum. Burrow density decreased according to salinity decreases around the discharged area. Crabs from the impacted area had a lower osmoregulatory capacity despite gill NKA activity remaining undisturbed. The decrease of the superoxide dismutase activity indicates changes in redox metabolism. However, both catalase activity and oxidative damage remained unchanged in both areas but were higher in posterior gills. These results indicate that WW release may induce osmoregulatory and redox imbalances, potentially explaining the decrease in crab density. Based on these results we conclude that WW release should be carefully monitored as crabs are key players involved in the bioremediation process.


Assuntos
Braquiúros/efeitos dos fármacos , Monitoramento Ambiental/métodos , Águas Residuárias/toxicidade , Poluentes Químicos da Água/toxicidade , Áreas Alagadas , Animais , Biodegradação Ambiental , Braquiúros/fisiologia , Ecossistema , França , Brânquias/efeitos dos fármacos , Brânquias/enzimologia , Hemolinfa/efeitos dos fármacos , Ilhas do Oceano Índico , Oxirredução , Salinidade , ATPase Trocadora de Sódio-Potássio/metabolismo , Águas Residuárias/química
4.
Proc Natl Acad Sci U S A ; 117(1): 479-485, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31871191

RESUMO

Populations of many marine species are only weakly synchronous, despite coupling through larval dispersal and exposure to synchronous environmental drivers. Although this is often attributed to observation noise, factors including local environmental differences, spatially variable dynamics, and chaos might also reduce or eliminate metapopulation synchrony. To differentiate spatially variable dynamics from similar dynamics driven by spatially variable environments, we applied hierarchical delay embedding. A unique output of this approach, the "dynamic correlation," quantifies similarity in intrinsic dynamics of populations, independently of whether their abundance is correlated through time. We applied these methods to 17 populations of blue crab (Callinectes sapidus) along the US Atlantic coast and found that their intrinsic dynamics were broadly similar despite largely independent fluctuations in abundance. The weight of evidence suggests that the latitudinal gradient in temperature, filtered through a unimodal response curve, is sufficient to decouple crab populations. As unimodal thermal performance is ubiquitous in ectotherms, we suggest that this may be a general explanation for the weak synchrony observed at large distances in many marine species, although additional studies are needed to test this hypothesis.


Assuntos
Braquiúros/fisiologia , Larva/fisiologia , Modelos Biológicos , Análise Espaço-Temporal , Animais , Oceano Atlântico , Monitorização de Parâmetros Ecológicos/estatística & dados numéricos , Dinâmica Populacional/estatística & dados numéricos , Temperatura , Estados Unidos
5.
Ecotoxicol Environ Saf ; 186: 109738, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31610357

RESUMO

Pharmaceuticals such as antidepressants are constantly released into the aquatic environment. Consequently, fluoxetine (FLX) and venlafaxine (VEN), the active molecules of Prozac© and Effexor©, are detected up to several µg.L-1 in freshwater and marine coastal waters. Both compounds act on the serotoninergic system, which may result in behavioural impairment, especially in juvenile animals presumed to be more susceptible to low concentrations than adults. The objective of this study was to determine whether environmental concentrations of FLX alone or combined with VEN modulate innate burying behaviour in two juvenile marine invertebrates, i.e. Sepia officinalis and Carcinus maenas. Juvenile cuttlefish were exposed from hatching to 30 days post-hatching to either FLX alone (i.e. 5 ng.L-1) or in mixture with VEN (i.e. either 2.5 ng.L-1 or 5 ng.L-1 of each antidepressant). Juvenile crabs (<2 cm carapace width) were exposed for a period of 22 days to 5 ng.L-1 of FLX and a mixture of 5 ng.L-1 of FLX and VEN each. Several parameters of sand-digging behaviour were analysed weekly in both species. The occurrence of sand-digging behaviour decreased in cuttlefish exposed to a mixture of FLX and VEN at the lowest concentration (2.5 ng.L-1 each). Because sand-digging behaviour improved in controls, this decrease was likely to be related to a modification of maturation and/or learning processes. At the mixture of 5 ng.L-1 VEN and FLX each, a better body covering was observed in juvenile crabs. In both species, innate behaviour was modified under exposure to mixtures of FLX and VEN at environmentally realistic concentrations. These alterations were observed at an early developmental stage, when animals are particularly prone to predation. Hence, modified maturation of behavioural traits and, putatively, learning processes by exposure to pseudo-persistent antidepressants may affect the survival of these two species in the long term.


Assuntos
Antidepressivos/toxicidade , Comportamento Animal/efeitos dos fármacos , Braquiúros/efeitos dos fármacos , Sepia/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Antidepressivos/análise , Braquiúros/fisiologia , Fluoxetina/análise , Fluoxetina/toxicidade , Sepia/fisiologia , Cloridrato de Venlafaxina/análise , Cloridrato de Venlafaxina/toxicidade , Poluentes Químicos da Água/análise
6.
Anim Reprod Sci ; 208: 106122, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31405473

RESUMO

The vitellogenesis-inhibiting hormone (VIH), also known as gonad-inhibiting hormone, is a neuropeptide hormone in crustaceans that belongs to the crustacean hyperglycemic hormone (CHH)-family peptide. There is regulation vitellogenesis by VIH during gonad maturation in crustaceans. A full-length Scylla olivacea VIH (Scyol-VIH) was identified through reverse transcription polymerase chain reaction and rapid amplification of cDNA ends. The open reading frame consists of 378 nucleotides, which encodes a 126-amino acid precursor protein, including a 22-residue signal peptide and a 103-amino acid mature peptide in which 6 highly conserved cysteine residues are present. There was expression of the Scyol-VIH gene in immature female Scylla olivacea in the eyestalk, brain and ventral nerve cord. The Scyol-VIH gene expression was localized to the eyestalk X-organ, brain neuronal clusters 6 and 11, and in multiple neuronal clusters of the ventral nerve cord. The relative abundance of Scyol-VIH mRNA transcript in the eyestalk was relatively greater in immature stage females, then decreased as ovarian maturation progressed. Furthermore, eyestalk Scyol-VIH increased after dopamine (5 µg/g BW) injection. The present research provides fundamental information about Scyol-VIH and its potential effect in controlling reproduction.


Assuntos
Braquiúros/fisiologia , Dopamina/farmacologia , Hormônios de Invertebrado/metabolismo , Ovário/crescimento & desenvolvimento , RNA Mensageiro/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Braquiúros/genética , Clonagem Molecular , Dopamina/administração & dosagem , Dopaminérgicos/farmacologia , Antagonistas de Dopamina/administração & dosagem , Antagonistas de Dopamina/farmacologia , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Hormônios de Invertebrado/genética , Ovário/metabolismo , Filogenia , RNA Mensageiro/genética , Serotonina/administração & dosagem , Serotonina/farmacologia , Serotoninérgicos/administração & dosagem , Serotoninérgicos/farmacologia , Maturidade Sexual , Espiperona/administração & dosagem , Espiperona/farmacologia , Fatores de Tempo
7.
Sci Total Environ ; 687: 768-779, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31412480

RESUMO

Metals are persistent pollutants, able to accumulate in the biota and magnify in trophic web. In the specific case of cadmium contamination, it has been the subject of considerable interest in recent years because of its biological effects and it is one of major pollutant in estuarine areas. Ucides cordatus is considered a mangrove local sentinel crab species in Brazil and there are previous studies reporting crab subpopulations living from pristine to heavily metal impacted areas in São Paulo coast (Southeastern Brazil). Taking into account the background knowledge about these subpopulations, we proposed the hypothesis that crabs from a highly polluted mangrove (Cubatão - CUB) have developed biological tolerance to cadmium compared to animals from an Environmental Protected Area (Jureia - JUR). Aiming to verify this hypothesis, we have investigated total bioaccumulation and subcellular partition of Cd, besides biomarkers' responses during a long-term exposure bioassay (28 days, with weekly sampling) using a supposedly safe Cd concentration (0.0022 mg L-1). Specimens from the pristine area (JUR) accumulated higher total Cd, as such as in its biologically active form in gills. Animals living in the polluted site (CUB) presented higher amounts of Cd in the mainly detoxifying tissue (hepatopancreas), which could be considered a pathway leading to tolerance for this metal. Multivariate analysis indicated that bioaccumulation (active, detoxified and total Cd) is linked to geno-cytotoxic damages. CUB subpopulation was considered more tolerant since it presented proportionally less damage and more capacity to allocate Cd in the main detoxifying forms and tissues.


Assuntos
Braquiúros/fisiologia , Cádmio/toxicidade , Monitoramento Ambiental , Espécies Sentinelas/fisiologia , Poluentes Químicos da Água/toxicidade , Áreas Alagadas , Animais , Brasil , Cádmio/análise , Hepatopâncreas , Poluentes Químicos da Água/análise
8.
Gene ; 719: 144074, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31446094

RESUMO

Kinesin-14 motor es-kifc1 is highly expressed in the male reproductive system of the Chinese mitten crab Eriocheir sinensis (E. sinensis). In addition to acrosomal formation, es-KIFC1 also tightly surrounds the nucleus and its specific mechanism remains unknown. During spermatogenesis, sperm nucleus dents into a cup-shaped structure with several radial arms and completed the nuclear decondensation. In this study, the spatial expression pattern of es-KIFC1 indicates a potential function in nuclear formation with the nuclear localization sequence (NLS) on N-terminal domain which is crucial for the translocation of es-KIFC1 into the nucleus. The Motor domain is associated with microtubule modulation and the Golgi vesicles positioning. Furthermore, the expression level of es-KIFC1 is not only related to the seasonal variation of crustacean development, but also associates with mature sperm storage. The double strand RNA (dsRNA) mediated RNA interference manifests that the cup-shaped sperm nucleus is remarkably malformed and even separates the chromatin throughout the nuclei at the last stage of spermiogenesis. Besides, the sperm nucleus almost disperses its structure and separates the chromatin into several segments throughout the nucleus showing an asymmetrical performance without cytoskeleton. In summary, these results indicate the importance of es-KIFC1 in microtubule positioning and the maintenance of the mature sperm nuclei.


Assuntos
Proteínas de Artrópodes/genética , Braquiúros/fisiologia , Núcleo Celular/metabolismo , Cinesina/genética , Espermatogênese/genética , Animais , Proteínas de Artrópodes/metabolismo , Núcleo Celular/ultraestrutura , Citoesqueleto/metabolismo , Cinesina/metabolismo , Masculino , Microtúbulos/metabolismo , Transporte Proteico , RNA de Cadeia Dupla/genética , Espermatozoides/ultraestrutura
9.
PLoS One ; 14(7): e0219260, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31269065

RESUMO

The Chinese mitten crab (Eriocheir sinensis) is an euryhaline crustacean, whose adults migrate downstream to estuaries for reproduction. Lipids are believed to be involved in salinity adaptation during migration. This study investigated the effects of different salinities (0, 6, 12, and 18‰) on the total lipids, neutral lipids, and polar lipids contents, and fatty acid profiles in the gonads, hepatopancreas, and muscles of adult E. sinensis after 40 days of salinity adaptation. The results showed that the males and females from 12‰ treatment had the highest contents of total lipids and neutral lipids in their hepatopancreas and total lipids in the muscles. Notably, salinity had a greater effect on the fatty acid profiles in the hepatopancreas compared to that in the gonads and muscles. The male hepatopancreas treated with 18‰ salinity had the highest percentage of total n-6 polyunsaturated fatty acid (∑n-6PUFA) in both neutral lipids and polar lipids, while the percentage of total n-3 polyunsaturated fatty acid (∑n-3PUFA) in neutral lipids and polar lipids decreased significantly with increasing salinity in males. In females, the 0‰ treatment had the highest percentages of total saturated fatty acids in neutral lipids and polar lipids in the hepatopancreas, while the highest ∑n-3PUFA and ∑n-6PUFA in neutral lipids and polar lipids were detected in the 12‰ treatment group. In conclusion, brackish water could promote the accumulations of total lipids and neutral lipids in the hepatopancreas and change the fatty acid profiles of adult E. sinensis, particularly in the hepatopancreas after long-term salinity adaptation.


Assuntos
Adaptação Fisiológica , Braquiúros/fisiologia , Lipídeos/química , Salinidade , Animais , Feminino , Gônadas/metabolismo , Hepatopâncreas/metabolismo , Masculino , Músculos/metabolismo , Análise de Componente Principal
10.
PLoS One ; 14(7): e0219555, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31344064

RESUMO

Understanding how increases in water temperature may affect winter dormancy period duration and overwinter survival are important for the effective conservation and management of estuarine species in the face of a warming climate. In this study, we determined the length of the overwintering period and the probability of overwinter survival of blue crab (Callinectes sapidus), an ecologically and economically important estuarine crustacean. Overwintering period length and probability of overwinter survival were determined using projected water temperatures up to the year 2100, derived from a harmonic model that utilized air temperatures from multi-model ensemble of regional-scale climate projections. Our estimates of warming water temperatures by 2100 in Chesapeake Bay indicate that winters will be up to 50% shorter and overwinter survival will increase by at least 20% compared to current conditions. The warmer conditions will lead to faster and prolonged seasonal growth, which, when combined with lower winter mortality, will lead to increased population productivity. The level of expression of this increased productivity will depend on the response of other elements of the Chesapeake Bay food web, as well as possible changes to fishery management policies over the same time period.


Assuntos
Comportamento Animal/fisiologia , Braquiúros/fisiologia , Temperatura Alta , Estações do Ano , Animais , Clima , Análise de Sobrevida
11.
Fish Shellfish Immunol ; 92: 367-376, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31200070

RESUMO

Oxidative stress plays a crucial role in ammonia nitrogen toxicity. In this study, the beneficial effects of dietary nano cerium oxide (nano CeO2) as a potent antioxidant were examined in the Chinese mitten crab (Eriocheir sinensis). Crabs were fed a diet supplemented with 0, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, or 12.8 mg/kg nano CeO2 for 60 d. The optimum supplementation level of nano CeO2 that significantly increased weight gain rate and decreased feed coefficient was 0.8 mg/kg. This level also offered immune protection when crabs were kept under ammonia nitrogen stress and/or exposed to pathogen infection (Aeromonas hydrophila). Supplementation with 0.8 mg/kg of CeO2 (i) relieved pathological damage to the hepatopancreas; (ii) increased hemocyte counts, including total number of hemocytes, granulocytes, and hyalinocytes; (iii) decreased malondialdehyde content and increased antioxidant enzyme activities of superoxide dismutase and catalase in the hemolymph; (iv) increased the activities of lysozyme, acid phosphatase, and alkaline phosphatase in the hemolymph; and (v) increased gene and protein expression of cathepsin L in the hepatopancreas. Mortality increased when crabs were injected with bacteria under ammonia nitrogen stress, but dietary supplementation with 0.8 mg/kg nano CeO2 decreased the mortality rate. Thus, the results of this study suggested that dietary supplementation with nano CeO2 in crabs promoted growth and up-regulated immunity to bacterial infection under ammonia nitrogen stress.


Assuntos
Amônia/efeitos adversos , Braquiúros/efeitos dos fármacos , Cério/metabolismo , Imunidade Inata/efeitos dos fármacos , Nanopartículas Metálicas , Estresse Oxidativo/efeitos dos fármacos , Ração Animal/análise , Animais , Braquiúros/crescimento & desenvolvimento , Braquiúros/imunologia , Braquiúros/fisiologia , Cério/administração & dosagem , Cério/farmacologia , Dieta , Suplementos Nutricionais/análise , Relação Dose-Resposta a Droga , Nanopartículas Metálicas/administração & dosagem , Distribuição Aleatória
12.
Bull Environ Contam Toxicol ; 103(3): 405-410, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31203409

RESUMO

Global trends in pesticide use can increase aquatic pollution and affect resident fisheries. Crabs exposed to organophosphate pesticides, such as chlorpyrifos, may increase production of reactive oxygen species (ROS), affecting the pro-oxidant/antioxidant balance. Zichiopsis collastinensis crabs were exposed to environmentally relevant concentrations of chlorpyrifos (0.1 and 0.5 µg L-1). Effects on the oxidative stress enzymes catalase, superoxide dismutase, glutathione S-transferases, glutathione reductase, and on thiobarbituric acid reactive substances and hydrogen peroxide concentrations were evaluated at four intervals during 96 h exposures. Exposures caused decreased GST activity and increased H2O2 levels in gills. There were modifications of GST, CAT and SOD activities in the hepatopancreas after 12 h of exposure, and an increase of H2O2 levels at every exposure interval observed. The present study proved that chlorpyrifos lead to oxidative stress in Z. collastinensis. However other enzymatic/non-enzymatic responses should be further investigated in order to be included as part of a battery of biomarkers, together with H2O2 levels, which is a parameter highly recommended to be taken into account.


Assuntos
Braquiúros/fisiologia , Clorpirifos/toxicidade , Inseticidas/toxicidade , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Braquiúros/metabolismo , Catalase/metabolismo , Clorpirifos/metabolismo , Monitoramento Ambiental , Água Doce , Brânquias/metabolismo , Glutationa Redutase/metabolismo , Hepatopâncreas/enzimologia , Peróxido de Hidrogênio/metabolismo , Inseticidas/metabolismo , Estresse Oxidativo/fisiologia , Praguicidas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Alimentos Marinhos , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/toxicidade
13.
Naturwissenschaften ; 106(7-8): 35, 2019 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-31201563

RESUMO

In semi-terrestrial crabs, the production of sounds has been recognized to be related to courtship communication dynamics. The present study aimed to assess if the crab Neohelice granulata (Varunidae) was able to emit acoustic signals and if they played a role in the crab's behaviour. We also assessed the locomotor behaviours to examine these parameters in different mating contexts of crabs. The study was divided into two different experimental conditions: 'solitary experiment' (consisting of three combination layouts with male, unreceptive and receptive females alone) and 'group experiment' (consisting of mixed combinations layouts of males, unreceptive, and receptive females). Synchronized acoustic and video monitoring systems were used to record the acoustic signals and locomotor behaviours of alone and grouped specimens. The greatest values of locomotor behavioural parameters were observed in layouts with receptive females alone and with 2 males plus 1 receptive female, probably related to courtship behaviour. N. granulata produced two distinct signals, a multi-pulse rasp signal (highest numbers were recorded in layouts with male alone and with 2 males plus 1 receptive female) and a single rasp signal. These results may suggest that males use the multi-rasp signal to advertise their presence to other males or to attract receptive females.


Assuntos
Comunicação Animal , Braquiúros/fisiologia , Comportamento Sexual Animal/fisiologia , Acústica , Animais , Feminino , Masculino , Água do Mar
14.
Biol Bull ; 236(3): 186-198, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31167091

RESUMO

Sporadic fluctuations in food availability may affect larval biology and post-metamorphic development in many marine invertebrates. In an experimental study in the laboratory, we investigated whether different regimes (1, 3, and 5 days) of initial starvation or feeding affect the survival and duration of the last planktotrophic larval stage (i.e., megalopa) of the neotropical mangrove fiddler crab Leptuca cumulanta. Newly metamorphosed crabs originating from megalopae starved for 1 and 3 days were cultured through the first 5 juvenile stages to further evaluate whether prior nutritional experience affects the post-larval performance of this species. All megalopae that were starved continuously died, while 80% of the larvae that were fed constantly metamorphosed successfully into the juvenile stage. Megalopae initially starved for 3 and 5 days exhibited lower survival (55% and 30% of larval metamorphosis, respectively) than larvae starved for only 1 day (85%) or fed constantly. The starvation periods (1, 3, and 5 days) also significantly prolonged the mean megalopal stage duration (12.8, 13.9, and 14.3 days, respectively) compared to the continuous feeding regime (10.6 days). Survival of the megalopae subjected to different periods of initial feeding (1, 3, and 5 days) was significantly lower (15.0%, 57.5%, and 62.5%, respectively) than survival of the larvae fed constantly. The mean megalopal stage duration, by contrast, did not vary among megalopae initially fed for 3 and 5 days or fed continuously (10.4 days). The larval starvation did not affect survival and carapace shape of juveniles, but it did alter their intermolt period, growth, and body size. These carryover effects were stronger in the first juvenile crab stage than in other juvenile stages. Our results indicate that the timing and duration of the starvation or feeding regime experienced by the megalopae may affect their successful survival and developmental period until metamorphosis to juvenile life. In addition, the preceding larval starvation associated with a prolonged larval period may also affect early juvenile performance in specific crab stages of L. cumulanta.


Assuntos
Braquiúros/crescimento & desenvolvimento , Privação de Alimentos , Metamorfose Biológica , Fenômenos Fisiológicos da Nutrição Animal , Animais , Braquiúros/fisiologia , Larva/crescimento & desenvolvimento , Larva/fisiologia
15.
Sci Total Environ ; 685: 836-846, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31247433

RESUMO

The effects of microplastic exposure on the non-specific immune responses and intestinal microflora remain unclear. In this study, juveniles of the Chinese mitten crab (Eriocheir sinensis) were exposed to different concentrations of microplastics (0, 0.04, 0.4, 4, and 40 mg/L) for 7, 14, and 21 days to explore their effects. Under microplastic-induced stress, the contents or activities of most immune-related factors [haemocyanin (Hc), alkaline phosphatase (AKP), phenoloxidase (PO), lysozyme (LSZ), and acid phosphatase (ACP)] decreased after an initial increase in the low-dose or short exposure times in the haemolymph and hepatopancreas. The trends in Hc and LSZ gene expression were consistent with the corresponding changes in enzyme activities. Moreover, the haemocyte expression of caspase and MyD88 in the groups with microplastic-induced stress was higher than that in the control group, whereas the expression levels in the hepatopancreas were first increased and then decreased. Furthermore, the relative abundance of Firmicutes and Bacteroidetes decreased following exposure to 40 mg/L microplastics, whereas that of Fusobacteria and Proteobacteria increased. These results indicate that microplastics affect immune enzyme activity and immune-related gene expression and change the diversity and composition of the intestinal microflora in E. sinensis.


Assuntos
Braquiúros/fisiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Imunidade Inata/efeitos dos fármacos , Plásticos/toxicidade , Poluentes da Água/toxicidade , Animais , Braquiúros/microbiologia
16.
Artigo em Inglês | MEDLINE | ID: mdl-31085294

RESUMO

This study investigates the combined effects of waterborne copper exposure and acute temperature change on oxygen consumption and the oxidative stress biomarkers, glutathione S-transferase (GST) and glutathione peroxidase (GPx), in the gills and hepatopancreas of the fiddler crab Minuca rapax. Crabs held at 25 °C were acclimated to 0 (control), 50, 250 or 500 µg Cu L-1 for 21 days, and were then subjected to 15, 25 and 35 °C for 24 h. Aerial oxygen consumption rates of crabs in copper free media increased with increasing temperature from 15 to 35 °C, Q10 values reaching ≈3. Crabs exposed to increasing copper concentrations exhibited variable responses, Q10 values falling to ≈1.5. Copper had no effect on oxygen consumption at 25 °C. However, at 35 °C, rates decreased in a clear concentration-response manner in the copper exposed crabs, revealing impaired aerobic capability. At 15 °C, oxygen consumption rates increased with copper concentration, except for a decrease at 500 µg Cu L-1. Gill GST activity was ≈2-fold that of the hepatopancreas, while hepatopancreas GPx activity was 3-fold that of the gills. Gill GST activities were reduced by copper exposure only at 25 °C while hepatopancreas GST activities were altered by copper at all temperatures. Hepatopancreas GST and GPx activities increased in crabs exposed to copper at 35 °C, revealing oxidative stress induction. Hepatopancreas GST and GPx activities were reduced in copper exposed crabs at 15 °C, suggesting a diminished capability to mitigate the effects of copper exposure at low temperature. These findings reveal that copper exposure increases oxygen consumption at low temperatures but decreases consumption at high temperature. Hepatopancreas GPx activities decreased at low temperature and increased at high temperature. These novel findings demonstrate that the interaction between copper exposure and temperature should be considered when evaluating biomarker activities in semi-terrestrial crabs.


Assuntos
Braquiúros/efeitos dos fármacos , Braquiúros/fisiologia , Cobre/toxicidade , Consumo de Oxigênio/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Feminino , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Transferase/metabolismo , Hepatopâncreas/efeitos dos fármacos , Hepatopâncreas/metabolismo , Masculino , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Temperatura , Poluentes Químicos da Água/toxicidade
17.
PLoS One ; 14(5): e0215743, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31042726

RESUMO

The diameter and vertical depth of sand crab tunnels in sandy beaches are usually restricted to a few centimeters scale and several tens of centimeters, respectively. We designed a study to determine what physical factors restrict tunnel diameter and predict the maximum attainable tunnel diameter and depth. We collected field data on the size and spatial distributions of ghost crab (Ocypode spp.) burrows on two sandy beaches (Kawage Beach in Tsu, Mie Prefecture, Japan and Sakieda Beach in Ishigaki, Okinawa Prefecture, Japan), where O. ceratophthalma dominants the ghost crab fauna. We measured burrow depths and distance from shoreline in concert with water content of sandy beaches. To explain our observed distributions of crab burrows in the field, we performed experiments in a lab microcosm, comprising a horizontal tunnel through wet sand. We measured the static stability of tunnel structures in relation to water content and two strengths computed from loading force exerted on the sand overlying the tunnels. By comparing field and experimental data, we found that crabs construct their burrows in appropriately wet zones (wet enough to provide sufficient cohesion of the sand grains in tunnel walls to prevent collapse) and that tunnel diameters and depths are sufficiently small to prevent deformation and collapse of their tunnels.


Assuntos
Braquiúros/fisiologia , Ecossistema , Animais , Praias , Japão
18.
Zoo Biol ; 38(4): 343-354, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31056807

RESUMO

Zoos increasingly transform their exhibitions from traditional one-species enclosures to more natural exhibits, that is, environments that capture part of an ecosystem including a selection of animals and plants that occur there. Thus, enhancing the experience of its human visitors while also allowing its residents to possibly show more natural behavior. In 2017 Royal Burger's Zoo (Arnhem, The Netherlands) created and opened a mangrove-like environment containing fiddler crabs. Fiddler crabs display a broad range of behaviors, and this research examines which wild-type behavior and behavioral patterns can be observed on a seminatural mudflat. The behavior shown by Uca rapax and Uca tangeri on the mudflat was counted each hour between 07:00 and 17:00. An asymmetric tidal regime was present in the enclosure including two high water periods. Various known fiddler crab behaviors, including waving and combat, were observed but no copulation. A clear pattern in exposed crabs on the mudflat was found, with low numbers visible in the early morning and the highest numbers present in the early afternoon, while number of visitors did not have a significant effect on this pattern. Interestingly, the highest abundances were not observed around the ebbing tide (07:00-09:00), as observed in the wild, but somewhat later, possibly due to the asymmetric tidal scheme or the interaction of tidal and daily rhythms. This study shows that in captivity, fiddler crabs indeed show a range of natural behaviors which is linked to the tidal and possibly daily rhythm as well.


Assuntos
Comportamento Animal , Braquiúros/genética , Braquiúros/fisiologia , Abrigo para Animais , Animais , Animais de Zoológico , Especificidade da Espécie
19.
Ecotoxicol Environ Saf ; 179: 9-16, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31022654

RESUMO

Ammonia is a major aquatic environmental pollutants. However, the underlying molecular mechanism of ammonia-induced toxicity is not fully understood. In this study, we investigated the physiological response and molecular mechanism in mud crab (Scylla paramamosain) exposed to the acute total ammonia (30 mg L-1) for 48 h. The results shown that ammonia exposure induced oxidative stress, and subsequently led to cytological damage and DNA damage. Transcriptome analysis was applied to investigate the key genes and pathways involved in the responses to ammonia exposure. A total of 722 differentially expressed genes (DEGs) (526 up-regulated and 196 down-regulated) were identified. DEGs mainly involved in pathways including metabolism, cellular processes, signal transduction and immune functions. Additionally, transcriptome analysis revealed that ATM/p53-Caspase3 pathway involved in apoptosis induced by ammonia stress. These results provided a new insight into the mechanism of the potential toxic effects of ammonia on crustaceans.


Assuntos
Amônia/toxicidade , Braquiúros/efeitos dos fármacos , Dano ao DNA , Transcriptoma/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Braquiúros/genética , Braquiúros/fisiologia , Perfilação da Expressão Gênica , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Transdução de Sinais
20.
Artigo em Inglês | MEDLINE | ID: mdl-30974344

RESUMO

Peptides are known to contribute to central pattern generator (CPG) flexibility throughout the animal kingdom. However, the role played by receptor diversity/complement in determining this functional flexibility is not clear. The stomatogastric ganglion (STG) of the crab, Cancer borealis, contains CPGs that are models for investigating peptidergic control of rhythmic behavior. Although many Cancer peptides have been identified, their peptide receptors are largely unknown. Thus, the extent to which receptor diversity/complement contributes to modulatory flexibility in this system remains unresolved. Here, a Cancer mixed nervous system transcriptome was used to determine the peptide receptor complement for the crab nervous system as a whole. Receptors for 27 peptide families, including multiple receptors for some groups, were identified. To increase confidence in the predicted sequences, receptors for allatostatin-A, allatostatin-B, and allatostatin-C were cloned, sequenced, and expressed in an insect cell line; as expected, all three receptors trafficked to the cell membrane. RT-PCR was used to determine whether each receptor was expressed in the Cancer STG. Transcripts for 36 of the 46 identified receptors were amplified; these included at least one for each peptide family except RYamide. Finally, two peptides untested on the crab STG were assessed for their influence on its motor outputs. Myosuppressin, for which STG receptors were identified, exhibited clear modulatory effects on the motor patterns of the ganglion, while a native RYamide, for which no STG receptors were found, elicited no consistent modulatory effects. These data support receptor diversity/complement as a major contributor to the functional flexibility of CPGs.


Assuntos
Proteínas de Artrópodes/genética , Braquiúros/genética , Neuropeptídeos/genética , Receptores de Neuropeptídeos/genética , Animais , Braquiúros/fisiologia , Rede Nervosa/fisiologia , Filogenia , Transcriptoma
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA