Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 284
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
J Neurosci Res ; 102(8): e25371, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39078068

RESUMO

Carnosine is a naturally occurring endogenous dipeptide with well-recognized anti-inflammatory, antioxidant, and neuroprotective effects at the central nervous system level. To date, very few studies have been focused on the ability of carnosine to rescue and/or enhance memory. Here, we used a well-known invertebrate model system, the pond snail Lymnaea stagnalis, and a well-studied associative learning procedure, operant conditioning of aerial respiration, to investigate the ability of carnosine to enhance long-term memory (LTM) formation and reverse memory obstruction caused by an immune challenge (i.e., lipopolysaccharide [LPS] injection). Exposing snails to 1 mM carnosine for 1 h before training in addition to enhancing memory formation resulted in a significant upregulation of the expression levels of key neuroplasticity genes (i.e., glutamate ionotropic receptor N-methyl-d-aspartate [NMDA]-type subunit 1-LymGRIN1, and the transcription factor cAMP-response element-binding protein 1-LymCREB1) in snails' central ring ganglia. Moreover, pre-exposure to 1 mM carnosine before an LPS injection reversed the memory deficit brought about by inflammation, by preventing the upregulation of key targets for immune and stress response (i.e., Toll-like receptor 4-LymTLR4, molluscan defense molecule-LymMDM, heat shock protein 70-LymHSP70). Our data are thus consistent with the hypothesis that carnosine can have positive benefits on cognitive ability and be able to reverse memory aversive states induced by neuroinflammation.


Assuntos
Carnosina , Lipopolissacarídeos , Lymnaea , Memória de Longo Prazo , Animais , Lymnaea/efeitos dos fármacos , Carnosina/farmacologia , Memória de Longo Prazo/efeitos dos fármacos , Memória de Longo Prazo/fisiologia , Lipopolissacarídeos/farmacologia , Gânglios dos Invertebrados/efeitos dos fármacos , Gânglios dos Invertebrados/metabolismo , Plasticidade Neuronal/efeitos dos fármacos , Plasticidade Neuronal/fisiologia , Condicionamento Operante/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos
2.
Bull Environ Contam Toxicol ; 112(6): 84, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38822851

RESUMO

We investigated the therapeutic effects of EDTA application for 14 and 28 days on cadmium (Cd) induced pond snail Lymnaea stagnalis (Linnaeus, 1758). The sublethal concentration of cadmium (63.4 mg/l Cd) caused tissue damages to the snail after an exposure for 28 days.In the groups treated with EDTA, the concentration of Cd in the foot, mantle and hepatopancreas tissues showed significantly decreased during the recovery period. The curative effects of EDTA on Cd-induced damage were assessed using a scoring system. Cadmium exposure led to histopathological changes including increased mucositis, pigment and protein cells, foot epithelium desquamation, muscle fibril damage, connective tissue cell atrophy, and increased lipid vacuoles in the mantle and hepatopancreas. However, these changes were less severe in snails treated with EDTA (2.00 mL/L for 28 day), indicating that EDTA reduces their susceptibility to heavy metal toxicity.


Assuntos
Cádmio , Ácido Edético , Lymnaea , Poluentes Químicos da Água , Animais , Cádmio/toxicidade , Lymnaea/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Hepatopâncreas/efeitos dos fármacos , Hepatopâncreas/patologia
3.
J Exp Biol ; 223(Pt 2)2020 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-31915202

RESUMO

Plasma membrane efflux transporters play crucial roles in the removal and release of both harmful and beneficial substances from the interior of cells and tissue types in virtually every extant species. They contribute to the clearance of a broad spectrum of exogenous and endogenous toxicants and harmful metabolites, including the reactive lipid aldehyde byproducts of lipid peroxidation that are a hallmark of cellular ageing. Here, we tested whether declining transporter functionality may contribute to functional decline in a snail model of neuronal ageing. Through measuring the removal of 5(6)-carboxyfluorescein, a known substrate for membrane efflux transporters, we provide, for the first time, physiological evidence for the existence of probenecid-, MK571- and glutathione-sensitive efflux transporters in (gastropod) neurons and demonstrate that their functionality declines with age. Our data support the idea that waning cellular detoxification capacity might be a significant factor in the escalation of (lipo-)toxicity observed in neuronal ageing.


Assuntos
Envelhecimento , Lymnaea/fisiologia , Proteínas de Membrana Transportadoras/metabolismo , Neurônios/fisiologia , Animais , Lymnaea/efeitos dos fármacos
4.
Ecotoxicol Environ Saf ; 188: 109882, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31698175

RESUMO

Microplastics attract widespread attention, including for their potential to transport toxic chemicals in the form of plasticisers and associated hydrophobic organic chemicals, such as polybrominated diphenyl ethers (PBDEs). The aims of this study were to investigate how nylon (polyamide) microplastics may affect PBDE accumulation in snails, and the acute effects of nylon particles and PBDEs on survival, weight change and inherent microbiome diversity and community composition of the pond snail Lymnaea stagnalis. Snails were exposed for 96 h to BDEs-47, 99, 100 and 153 in the presence and absence of 1% w/w nylon microplastics in quartz sand sediment. No mortality was observed over the exposure period. Snails not exposed to microplastics lost significantly more weight compared to those exposed to microplastics. Increasing PBDE concentration in the sediment resulted in an increased PBDE body burden in the snails, however microplastics did not significantly influence total PBDE uptake. Based on individual congeners, uptake of BDE 47 by snails was significantly reduced in the presence of microplastics. The diversity and composition of the snail microbiome was not significantly altered by the presence of PBDEs nor by the microplastics, singly or combined. Significant effects on a few individual operational taxonomic units (OTUs) occurred when comparing the highest PBDE concentration with the control treatment, but in the absence of microplastics only. Overall within these acute experiments, only subtle effects on weight loss and slight microbiome alterations occurred. These results therefore highlight that L. stagnalis are resilient to acute exposures to microplastics and PBDEs, and that microplastics are unlikely to influence HOC accumulation or the microbiome of this species over short timescales.


Assuntos
Éteres Difenil Halogenados/metabolismo , Lymnaea/efeitos dos fármacos , Microbiota/efeitos dos fármacos , Microplásticos/toxicidade , Poluentes Químicos da Água/metabolismo , Animais , Carga Corporal (Radioterapia) , Exposição Ambiental/análise , Retardadores de Chama/análise , Retardadores de Chama/metabolismo , Retardadores de Chama/toxicidade , Éteres Difenil Halogenados/análise , Éteres Difenil Halogenados/toxicidade , Lymnaea/metabolismo , Lymnaea/microbiologia , Nylons/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
5.
Arch Environ Contam Toxicol ; 79(1): 89-100, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32274555

RESUMO

Gastropod mollusks have achieved an eminent importance as biological indicators of environmental quality. In the present study, we applied a multibiomarker approach to evaluate its applicability for the pond snail Lymnaea stagnalis, exposed to common industrial and agricultural pollutants at environmentally relevant concentrations. The snails were exposed to copper (Cu2+, 10 µg L-1), zinc (Zn2+, 130 µg L-1), cadmium (Cd2+, 15 µg L-1), or the thiocarbamate fungicide "Tattoo" (91 µg L-1) during 14 days. Metal treatment and exposure to "Tattoo" caused variable patterns of increase or decrease of metal levels in the digestive gland, with a clear accumulation of only Cd and Zn after respective metal exposure. Treatment with Cu and "Tattoo" caused an increase of cytochrome P450-related EROD activity. Glutathione S-transferase was inhibited by exposure to Cu, Zn, and "Tattoo." Treatment with the "Tattoo" led to an inhibition of cholinesterase activity, whereas Cu and Cd increased its activity. Caspase-3 activity was enhanced by up to 3.3 times in all treatments. A nearly uniform inhibitory effect for oxidative stress response parameters was observed in all kinds of exposure, revealing an inhibition of superoxide dismutase (Mn-SOD) activity, a depression of glutathione (GSH and GSSG) and of protein carbonyl levels. Pollutant-specific effects were observed for the catalase activity, superoxide anion production, and lipid peroxidation levels. Due to the high response sensitivity of Lymnaea stagnalis to chemical impacts, we suggest our study as a contribution for biomarker studies with this species under field conditions.


Assuntos
Fungicidas Industriais/toxicidade , Lymnaea/efeitos dos fármacos , Metais Pesados/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Tiocarbamatos/toxicidade , Oligoelementos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Monitoramento Ambiental/métodos , Fungicidas Industriais/metabolismo , Glutationa/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Lymnaea/metabolismo , Metais Pesados/metabolismo , Lagoas/química , Superóxido Dismutase/metabolismo , Tiocarbamatos/metabolismo , Oligoelementos/metabolismo , Ucrânia , Poluentes Químicos da Água/metabolismo
6.
Bull Environ Contam Toxicol ; 103(2): 255-260, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31062039

RESUMO

Ecological effects of gold nano-particles (AuNP) are examined due to growing use in consumer and industrial materials. This study investigated uptake and movement of AuNPs through an aquatic food chain. Simple (single-species) and diverse (multi-species) periphyton communities were exposed to AuNP (0, 100, 500 µg L-1 treatments). AuNP quickly aggregated and precipitated from the water column, suggesting it is an insignificant route of AuNP exposure even at elevated concentrations. Gold was measured in 100 and 500 µg L-1 periphyton treatments. Gold accumulation was similar between periphyton treatments, suggesting physical processes were important for AuNP basal accumulation. Hyalella azteca and Lymnea stagnalis whole body tissue analysis indicated gold accumulation may be attributed to different feeding mechanisms, general versus selective grazing, respectively. Results suggest trophic transfer of AuNP is organism specific and aggregation properties of AuNP are important when considering fate of nano-particles in the environment and movement through aquatic food webs.


Assuntos
Anfípodes/efeitos dos fármacos , Ouro/análise , Lymnaea/efeitos dos fármacos , Nanopartículas Metálicas/análise , Perifíton/efeitos dos fármacos , Poluentes Químicos da Água/análise , Anfípodes/química , Animais , Exposição Dietética , Cadeia Alimentar , Lymnaea/química , Especificidade da Espécie
7.
Bull Environ Contam Toxicol ; 103(4): 551-558, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31435685

RESUMO

This study investigated the effect of persistent heavy metal exposure on the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) of the freshwater snail, Lymnaea natalensis. Malondialdehyde (MDA) levels were also measured as an index of lipid peroxidation. The snails were exposed to cadmium, copper, lead and mercury for a total of 28 days at 0.1 mg/L, 0.1 mg/L, 0.2 mg/L and 0.1 mg/L respectively. Samples were collected at 1, 7, 14, 21 and 28 days intervals. Analysis of SOD showed significant initial increases in enzyme activity following exposure to copper, lead and mercury, while cadmium exposures caused increases from Day 14 onwards. Copper, cadmium and lead caused significant initial increases in CAT activity and mercury caused an increase only on Day 28. Copper caused a significant increase in GPx activity on Day 28 while MDA levels diminished significantly at Days 7-28. Similarly, cadmium caused significant increases of GPx activity on Day 28 whereas MDA levels were significantly reduced. Lead also caused a significant increase in GPx activity on Days 14-28 whilst no significant changes occurred in MDA levels. Mercury exposures caused significant increases in GPx activity on Days 7 and 21, whilst MDA levels were significantly reduced on Days 7 and 14. These findings suggest that persistent exposure of snails to heavy metals induces the antioxidant defence system, and decreases lipid peroxidation.


Assuntos
Antioxidantes/metabolismo , Água Doce/química , Lymnaea/efeitos dos fármacos , Lymnaea/enzimologia , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Catalase/metabolismo , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , Superóxido Dismutase/metabolismo
8.
Neurobiol Learn Mem ; 149: 1-9, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29412170

RESUMO

The therapeutic efficacy of the synthetic ß-adrenergic receptor blocker, propranolol, for the treatment of post-traumatic stress disorder (PTSD) is currently being debated. Mixed results have been published regarding propranolol's ability to disrupt the consolidation and reconsolidation of memories. Here, we use the invertebrate model Lymnaea to study propranolol's ability to disrupt consolidation of memories formed under varying various types of stress which cause differing degrees of emotional memory. We show that when propranolol is administered immediately following operant conditioning, only the consolidation process of memories enhanced by individual stressors (i.e. a non-emotional memory) is susceptible to disruption. However, when propranolol is administered prior to training, only memories enhanced by a combination of stressors leading to an emotional memory are susceptible to disruption. These data suggest that the time of propranolol administration, as well as the type of memory formed play a key role in propranolol's ability to obstruct memory consolidation.


Assuntos
Antagonistas Adrenérgicos beta/farmacologia , Emoções/efeitos dos fármacos , Lymnaea/efeitos dos fármacos , Consolidação da Memória/efeitos dos fármacos , Propranolol/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Animais
9.
Neurobiol Learn Mem ; 148: 20-29, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29294381

RESUMO

The pond snail Lymnaea stagnalis learns conditioned taste aversion (CTA) and consolidates it into long-term memory (LTM). How well they learn and form memory depends on the degree of food deprivation. Serotonin (5-HT) plays an important role in mediating feeding, and insulin enhances the memory consolidation process following CTA training. However, the relationship between these two signaling pathways has not been addressed. We measured the 5-HT content in the central nervous system (CNS) of snails subjected to different durations of food deprivation. One-day food-deprived snails, which exhibit the best learning and memory, had the lowest 5-HT content in the CNS, whereas 5-day food-deprived snails, which do not learn, had a high 5-HT content. Immersing 1-day food-deprived snails in 5-HT impaired learning and memory by causing an increase in 5-HT content, and that the injection of insulin into these snails reversed this impairment. We conclude that insulin rescues the CTA deficit and this may be due to a decrease in the 5-HT content in the CNS of Lymnaea.


Assuntos
Aprendizagem da Esquiva/fisiologia , Comportamento Animal/fisiologia , Sistema Nervoso Central/metabolismo , Disfunção Cognitiva , Condicionamento Psicológico/fisiologia , Privação de Alimentos/fisiologia , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Lymnaea/fisiologia , Memória de Longo Prazo/fisiologia , Serotonina/metabolismo , Percepção Gustatória/fisiologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Sistema Nervoso Central/efeitos dos fármacos , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/fisiopatologia , Condicionamento Psicológico/efeitos dos fármacos , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Lymnaea/efeitos dos fármacos , Lymnaea/metabolismo , Memória de Longo Prazo/efeitos dos fármacos , Percepção Gustatória/efeitos dos fármacos , Fatores de Tempo
10.
Ecotoxicology ; 27(4): 477-484, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29524054

RESUMO

Recent studies have highlighted that antidepressants such as the selective serotonin reuptake inhibitors (SSRIs) entering aquatic systems through wastewater discharges might impact organisms at environmentally relevant concentrations. In this study, two snail species (Gibbula unbilicalis and Lymnea stagnalis) representing the marine and freshwater environments were exposed to a large range of fluoxetine concentrations (1 ng L-1-1 mg L-1) and two distinct behaviours (foot detachment and righting time) were recorded. Fluoxetine significantly caused foot detachment only at the higher of the concentrations (1 mg L-1) in both species during the course of this short term 1.5 h and 4 h exposures. In this study, lowest observed effect concentrations (LOECs) for foot detachment fell repeatedly within the range for other gastropod snails exposed to fluoxetine. Fluoxetine effected righting times in a concentration dependant manner but only significantly within G. unbilicalis in the highest concentration. Reviewing existing data on the effects of antidepressants on a range of endpoints in gastropod molluscs reveals wide variability of results. The importance of publishing 'negative' and/or non-dramatic results to aid risk assessment are discussed along with the variability between antidepressants, model species, experimental designs and endpoints.


Assuntos
Fluoxetina/toxicidade , Inibidores Seletivos de Recaptação de Serotonina/toxicidade , Caramujos/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Relação Dose-Resposta a Droga , Lymnaea/efeitos dos fármacos , Atividade Motora/efeitos dos fármacos , Fatores de Tempo
11.
Neurobiol Learn Mem ; 141: 189-198, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28450080

RESUMO

The pond snail Lymnaea stagnalis is capable of learning taste aversion by pairing presentations of a sucrose solution and an electric shock and consolidating it into long-term memory (LTM), which is referred to as conditioned taste aversion (CTA). We asked here if the neurotransmitter octopamine is involved in CTA. We first determined the levels of octopamine and its catabolites in the central nervous system (CNS) of snails with varying degrees of food deprivation, because CTA grades are correlated with degrees of food deprivation. We next manipulated the octopamine signaling using both an agonist and an antagonist of octopamine receptors and correlated their respective effects with CTA grades. We found that snails with the least amount of food-deprivation obtained the best CTA grade and had low levels of octopamine; whereas the most severely food-deprived snails did not form CTA and had the highest CNS octopamine levels. In modestly food-deprived snails, octopamine application increased the basal level of feeding response to a sucrose solution, and it did not obstruct CTA formation. Application of phentolamine, an octopamine receptor antagonist, to the most severely food-deprived snails decreased the basal level of feeding elicited by sucrose, but it did not enhance CTA formation. We conclude that octopamine involvement in CTA formation in Lymnaea is at best weak, and that the changes in CNS octopamine content are an epiphenomenon.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Sistema Nervoso Central/metabolismo , Octopamina/metabolismo , Paladar/efeitos dos fármacos , Animais , Aprendizagem da Esquiva/fisiologia , Privação de Alimentos/fisiologia , Lymnaea/efeitos dos fármacos , Lymnaea/fisiologia , Octopamina/farmacologia , Fentolamina/farmacologia , Receptores de Amina Biogênica/agonistas , Receptores de Amina Biogênica/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Paladar/fisiologia
12.
J Exp Biol ; 220(Pt 17): 3026-3038, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28855319

RESUMO

Cannabinoids are hypothesized to play an important role in modulating learning and memory formation. Here, we identified mRNAs expressed in Lymnaeastagnalis central nervous system that encode two G-protein-coupled receptors (Lymnaea CBr-like 1 and 2) that structurally resemble mammalian cannabinoid receptors (CBrs). We found that injection of a mammalian CBr agonist WIN 55,212-2 (WIN 55) into the snail before operant conditioning obstructed learning and memory formation. This effect of WIN 55 injection persisted for at least 4 days following its injection. A similar obstruction of learning and memory occurred when a severe traumatic stimulus was delivered to L. stagnalis In contrast, injection of a mammalian CBr antagonist AM 251 enhanced long-term memory formation in snails and reduced the duration of the effects of the severe traumatic stressor on learning and memory. Neither WIN 55 nor AM 251 altered normal homeostatic aerial respiratory behaviour elicited in hypoxic conditions. Our results suggest that putative cannabinoid receptors mediate stressful stimuli that alter learning and memory formation in Lymnaea This is also the first demonstration that putative CBrs are present in Lymnaea and play a key role in learning and memory formation.


Assuntos
Canabinoides/farmacologia , Lymnaea/efeitos dos fármacos , Receptores Acoplados a Proteínas G/genética , Animais , Benzoxazinas/farmacologia , Condicionamento Operante , Aprendizagem/efeitos dos fármacos , Lymnaea/genética , Lymnaea/fisiologia , Memória/efeitos dos fármacos , Morfolinas/farmacologia , Naftalenos/farmacologia , Piperidinas/farmacologia , Pirazóis/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptores Acoplados a Proteínas G/metabolismo
13.
Ecotoxicol Environ Saf ; 139: 358-366, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28189777

RESUMO

This is a pioneering study in the ecotoxicological assessment of immunotoxic effects of the three selected drugs of concern to a freshwater gastropod species. Lymnaea stagnalis was exposed in the laboratory for 3 days to three drugs used for immune systems: diclofenac (nonsteroidal anti-inflammatory drug), cyclophosphamide (anti-cancer immunosuppressive drug) or cyclosporine A (anti-xenograft immunosuppressive drug). Exposure ranges included environmental realistic (1-10µgL-1) and therapeutic concentrations (100-1000µgL-1). At the end of exposure times, the immune parameters of individual snails were measured: hemocyte density and viability, hemocyte phagocytosis capacity and hemocyte-related oxidative activities (basal and NADPH-oxidase stimulated with zymosan particles). Diclofenac and cyclosporine A induced immune responses, although the effects were not strong. No immunosuppression was observed. Such subtle immunomodulations bring further interrogations regarding their long-term immunotoxicity and possible resulting tradeoffs with life-history traits. On the other hand, the prodrug cyclophosphamide did not induce significant immune responses. Since metabolism pathways differ greatly between vertebrates and invertebrates, this study also suggests that relevant vertebrate metabolites should be included in the immunotoxicity assessment of pharmaceuticals in non-target invertebrate species. Finally, the possible interactive effects of these pharmaceuticals sharing similar modes of action or effects features should also be explored.


Assuntos
Anti-Inflamatórios não Esteroides/toxicidade , Ciclofosfamida/toxicidade , Ciclosporina/toxicidade , Diclofenaco/toxicidade , Imunossupressores/toxicidade , Lymnaea/imunologia , Animais , Contagem de Células Sanguíneas , Sobrevivência Celular/efeitos dos fármacos , Hemócitos/efeitos dos fármacos , Hemócitos/imunologia , Lymnaea/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade
14.
Artigo em Inglês | MEDLINE | ID: mdl-27138222

RESUMO

Lymnaea exposed to crayfish effluent (CE) gain an enhanced ability to form long-term memory (LTM). We test the hypothesis that a single CE exposure and operant conditioning training leads to long lasting changes in the capability of snails to form LTM when tested in pond water four weeks later. We trained both juvenile and adult snails with a single 0.5 h training session in CE and show that LTM was present 24 h later. Snails trained in a similar manner in just pond water show no LTM. We then asked if such training in CE conferred enhanced memory forming capabilities on these snails four weeks later. That is, would LTM be formed in these snails four weeks later following a single 0.5 h training session in pond water? We found that both adult and juvenile snails previously trained in CE one month previously had enhanced LTM formation abilities. The injection of a DNA methylation blocker, 5-AZA, prior to training in adult snails blocked enhanced LTM formation four weeks later. Finally, this enhanced LTM forming ability was not passed on to the next generation of snails.


Assuntos
Lymnaea , Memória de Longo Prazo , Análise de Variância , Animais , Astacoidea , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Condicionamento Operante/efeitos dos fármacos , Metilação de DNA/efeitos dos fármacos , Decitabina , Inibidores Enzimáticos/farmacologia , Epigênese Genética/efeitos dos fármacos , Água Doce , Lymnaea/efeitos dos fármacos , Lymnaea/crescimento & desenvolvimento , Lymnaea/metabolismo , Memória de Longo Prazo/efeitos dos fármacos , Lagoas , Respiração , Olfato , Fatores de Tempo
15.
J Exp Biol ; 219(Pt 6): 816-23, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26823103

RESUMO

The ability to remember is influenced by environmental and lifestyle factors, such as stress and diet. A flavanol contained in chocolate, epicatechin (Epi), has been shown to enhance long-term memory (LTM) formation in Lymnaea. Combining two stressors (low-calcium pond water and crowding) blocks learning and all forms of memory; that is, this combination of environmentally relevant stressors creates a memory-unfriendly state. We tested the hypothesis that Epi will immediately reverse the memory-unfriendly state, i.e. that snails in the memory-deficit state when trained in Epi will immediately become competent to learn and form memory. We found that Epi not only reverses the memory-deficit state but also further enhances LTM formation. Thus, a naturally occurring bioactive plant compound can overcome a memory-unfriendly state. This supports the idea that bioactive substances may mitigate memory-making deficits that, for example, occur with ageing.


Assuntos
Cacau/química , Catequina/farmacologia , Lymnaea/efeitos dos fármacos , Animais , Condicionamento Operante , Aglomeração , Água Doce/química , Aprendizagem/efeitos dos fármacos , Lymnaea/fisiologia , Memória de Longo Prazo/efeitos dos fármacos , Estresse Fisiológico
16.
Environ Sci Technol ; 50(3): 1552-60, 2016 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-26698541

RESUMO

Whereas feeding inhibition caused by exposure to contaminants has been extensively documented, the underlying mechanism(s) are less well understood. For this study, the behavior of several key feeding processes, including ingestion rate and assimilation efficiency, that affect the dietary uptake of Cu were evaluated in the benthic grazer Lymnaea stagnalis following 4-5 h exposures to Cu adsorbed to synthetic hydrous ferric oxide (Cu-HFO). The particles were mixed with a cultured alga to create algal mats with Cu exposures spanning nearly 3 orders of magnitude at variable or constant Fe concentrations, thereby allowing first order and interactive effects of Cu and Fe to be evaluated. Results showed that Cu influx rates and ingestion rates decreased as Cu exposures of the algal mat mixture exceeded 10(4) nmol/g. Ingestion rate appeared to exert primary control on the Cu influx rate. Lysosomal destabilization rates increased directly with Cu influx rates. At the highest Cu exposure where the incidence of lysosomal membrane damage was greatest (51%), the ingestion rate was suppressed 80%. The findings suggested that feeding inhibition was a stress response emanating from excessive uptake of dietary Cu and cellular toxicity.


Assuntos
Cobre/toxicidade , Compostos Férricos/toxicidade , Lymnaea/efeitos dos fármacos , Adsorção , Animais , Dieta , Comportamento Alimentar/efeitos dos fármacos , Lisossomos/efeitos dos fármacos
17.
Environ Sci Technol ; 50(7): 3937-44, 2016 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-26900769

RESUMO

Many chemicals in use end up in the aquatic environment. The toxicity of water samples can be tested with bioassays, but a metabolomic approach has the advantage that multiple end points can be measured simultaneously and the affected metabolic pathways can be revealed. A current challenge in metabolomics is the study of mixture effects. This study aims at investigating the toxicity of an environmental extract and its most abundant chemicals identified by target chemical analysis of >100 organic micropollutants and effect-directed analysis (EDA) using the acetylcholinesterase (AChE) bioassay and metabolomics. Surface water from an agricultural area was sampled with a large volume solid phase extraction (LVSPE) device using three cartridges containing neutral, anionic, and cationic sorbents able to trap several pollutants classes like pharmaceuticals, pesticides, PAHs, PCBs, and perfluorinated surfactants. Targeted chemical analysis and AChE bioassay were performed on the cartridge extracts. The extract of the neutral sorbent cartridge contained most of the targeted chemicals, mainly imidacloprid, thiacloprid, and pirimicarb, and was the most potent AChE inhibitor. Using an EDA approach, other AChE inhibiting candidates were identified in the neutral extract, such as carbendazim and esprocarb. Additionally, a metabolomics experiment on the central nervous system (CNS) of the freshwater snail Lymnaea stagnalis was conducted. The snails were exposed to the extract, the three most abundant chemicals individually, and a mixture of these. The extract disturbed more metabolic pathways than the three most abundant chemicals individually, indicating the contribution of other chemicals. Most pathways perturbed by the extract exposure overlapped with those related to exposure to neonicotinoids, like the polyamine metabolism involved in CNS injuries. Metabolomics for the straightforward comparison between a complex mixture and single compound toxicity is still challenging but, compared to traditional biotesting, is a promising tool due to its increased sensitivity.


Assuntos
Acetilcolinesterase/metabolismo , Ensaios Enzimáticos/métodos , Lymnaea/efeitos dos fármacos , Metabolômica/métodos , Praguicidas/toxicidade , Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade , Animais , Bioensaio , Inibidores da Colinesterase/metabolismo , Redes e Vias Metabólicas , Poliaminas/metabolismo
18.
Regul Toxicol Pharmacol ; 81: 47-56, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27461040

RESUMO

This paper presents the results from two ring-tests addressing the feasibility, robustness and reproducibility of a reproduction toxicity test with the freshwater gastropod Lymnaea stagnalis (RENILYS strain). Sixteen laboratories (from inexperienced to expert laboratories in mollusc testing) from nine countries participated in these ring-tests. Survival and reproduction were evaluated in L. stagnalis exposed to cadmium, tributyltin, prochloraz and trenbolone according to an OECD draft Test Guideline. In total, 49 datasets were analysed to assess the practicability of the proposed experimental protocol, and to estimate the between-laboratory reproducibility of toxicity endpoint values. The statistical analysis of count data (number of clutches or eggs per individual-day) leading to ECx estimation was specifically developed and automated through a free web-interface. Based on a complementary statistical analysis, the optimal test duration was established and the most sensitive and cost-effective reproduction toxicity endpoint was identified, to be used as the core endpoint. This validation process and the resulting optimized protocol were used to consolidate the OECD Test Guideline for the evaluation of reproductive effects of chemicals in L. stagnalis.


Assuntos
Lymnaea/efeitos dos fármacos , Projetos de Pesquisa , Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade , Animais , Cloreto de Cádmio/toxicidade , Tamanho da Ninhada/efeitos dos fármacos , Relação Dose-Resposta a Droga , Estudos de Viabilidade , Fidelidade a Diretrizes , Guias como Assunto , Imidazóis/toxicidade , Modelos Estatísticos , Óvulo/efeitos dos fármacos , Análise de Regressão , Reprodutibilidade dos Testes , Reprodução/efeitos dos fármacos , Projetos de Pesquisa/normas , Medição de Risco , Fatores de Tempo , Testes de Toxicidade/normas , Acetato de Trembolona/toxicidade , Compostos de Trialquitina/toxicidade
19.
Toxicol Ind Health ; 32(1): 143-53, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24081640

RESUMO

Paraquat has been shown to be a highly toxic compound for humans and animals, and many cases of acute poisoning and death have been reported over the past few decades. The present study was undertaken to evaluate comprehensively herbicides (Paraquat) and some plant extracts to biochemical aspects of Lymnaea natalensis snails. It was found that the exposure of L. natalensis to Paraquat and plant extracts led to a significant reduction in the infectivity of Fasciola gigantica miracidia to the snail. The glucose level in hemolymph of exposed snails was elevated, while the glycogen showed a decrease in soft tissues when compared with the control group. In addition, the activity level of some enzymes representing glycolytic enzymes as hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK), lactate dehydrogenase (LDH), and glucose phosphate isomerase (GPI) in snail's tissues were reduced in response to the treatment. It was concluded that the pollution of the aquatic environment by herbicide would adversely affect the metabolism of the L. natalensis snails. Snails treated with Agave attenuate, Ammi visnaga, and Canna iridiflora plant had less toxic effect compared to snails treated with Paraquat.


Assuntos
Herbicidas/toxicidade , Lymnaea/efeitos dos fármacos , Paraquat/toxicidade , Extratos Vegetais/toxicidade , Animais , Fasciola/crescimento & desenvolvimento , Glucose-6-Fosfato Isomerase/metabolismo , Hexoquinase/metabolismo , L-Lactato Desidrogenase/metabolismo , Dose Letal Mediana , Lymnaea/metabolismo , Lymnaea/parasitologia , Fosfofrutoquinases/metabolismo , Compostos Fitoquímicos/toxicidade , Piruvato Quinase/metabolismo
20.
Pharm Biol ; 54(4): 726-31, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26429590

RESUMO

CONTEXT: The persistence of fascioliasis in many developing countries urges the search for simple, cheap, and effective substances. In this view, plants provide interesting molluscicidal activities thanks to the secondary metabolites they produce. The genus Solanum is known for its potent effect on vector snails. OBJECTIVE: The molluscicidal activity of Solanum elaeagnifolium Cav. (Solanaceae) seeds against Galba truncatula Müll. (Lymnaeidae), intermediate host of Fasciola hepatica L. (Fasciolidae), was evaluated. MATERIALS AND METHODS: Solanum elaeagnifolium seeds were powdered and successively extracted using n-hexane, methylene chloride, acetone, and methanol, for 20 h each. After filtration, solvents were evaporated. An acid-base treatment was conducted on seed methanolic extract to isolate total alkaloids and ß-solamarine. Total saponins fraction was obtained after successive macerations and evaporations. The molluscicidal activity was evaluated by subjecting snails, in groups of 10, for 48 h to 500 mL of extracts, fractions, and pure product aqueous solutions, each containing amounts, ranging from 1 to 50 mg of plant material in 5 mg increments. RESULTS: The methanolic extract of seeds, ß-solamarine isolated for the first time from this plant and total saponins fraction showed very potent activities on snails, giving respective median lethal concentrations (LC50) of 1.18, 0.49, and 0.94 mg/L. Total alkaloids fraction obtained from the methanolic extract was less active giving an LC50 value of 14.67 mg/L. DISCUSSION AND CONCLUSION: This study emphasizes that glycoalkaloids and saponins of Solanum elaeagnifolium are potent molluscicidal agents. Seed methanolic extract, ß-solamarine, and total saponins fraction may be used as molluscicides.


Assuntos
Fasciola hepatica/efeitos dos fármacos , Lymnaea/efeitos dos fármacos , Moluscocidas/farmacologia , Extratos Vegetais/farmacologia , Sementes , Alcaloides de Solanáceas/farmacologia , Solanum , Animais , Fasciola hepatica/metabolismo , Lymnaea/metabolismo , Moluscocidas/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Caramujos , Alcaloides de Solanáceas/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA