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Sample records for lymnaea cubensis molusco

  1. [Molluscacidal activity of Paraiso (Melia azedarach L.) (Meliaceae) on Lymnaea cubensis, host snail of fascioliasis].

    PubMed

    Piña Perez, M; Diéguez Fernandez, L; Abreu Guirado, O A; Vázquez Capote, R; González Aguilar, G

    1998-06-01

    Fasciolosis is a source of serious economic loss in various regions of Brazil and when control measures of its host (molluscs) are not taken under favorable ecological conditions, isolated cases of human Fasciolosis may occur. Among the alternative measures for its control is the use of vegetable extracts and the purpose of this project is the assessment of the use of juice extracted from the fruit and seeds of the Paraiso plant (Melia azedarach L.) in the control of Lymnaea cubensis, the main vector of Fasciolosis in Cuba. Various concentrations of the juice extracted from the Paraiso fruit (Melia azedarach L.) were tested to determine the average and maximum lethal doses (DL50 and DL90' respectively) used in a computerized PROBIT-LOG program. Seven experimental series were undertaken, 72 molluscs being used in each of them. Three groups of ten molluscs were tested to determine the effect on cardiac frequency, two of them being treated with CL50 = 0.88627 and CL90 = 1.7641, respectively, the third being used as control. A considerable effect of both doses on the cardiac frequency of the mollusc studied was observed. The results were encouraging, for they demonstrated the potential use of this plant in the control of undesirable molluscs.

  2. Characterisation of Lymnaea cubensis, L. viatrix and L. neotropica n. sp., the main vectors of Fasciola hepatica in Latin America, by analysis of their ribosomal and mitochondrial DNA.

    PubMed

    Bargues, M D; Artigas, P; Mera Y Sierra, R L; Pointier, J P; Mas-Coma, S

    2007-10-01

    Although, in the endemic areas throughout the world, human fascioliasis presents varying patterns in its epidemiology, the species of lymnaeid snail that act as intermediate hosts and vectors are always crucial in the transmission of the causative parasites. Species in the Galba/Fossaria group of snails, such as Lymnaea cubensis, L. viatrix var. A ventricosa, L. viatrix var. B elongata and Galba truncatula, appear to be frequently involved in the transmission of Fasciola hepatica in Central and South America, although specific classification within this morphologically and anatomically confusing group is often very difficult. To explore the potential use of molecular analyses in the identification of vector snails, regions of the ribosomal DNA - the small subunit (18S) gene and internal transcribed spacers (ITS-2 and ITS-1) - and of the mitochondrial DNA - the cytochrome c oxidase subunit I (COI) - of wild-caught lymnaeid snails of L. cubensis, L. viatrix var. A ventricosa, L. viatrix var. B elongata and G. truncatula have been sequenced. The samples of the Latin American species included specimens from the respective type localities. The genetic distances observed and the results of phylogenetic analyses demonstrate that two different species exist within L. viatrix. Lymnaea neotropica n. sp. (=L. viatrix var. B elongata) is here proposed for specimens from Lima, Peru, and is differentiated from L. viatrix (=L. viatrix var. A ventricosa), L. cubensis and G. truncatula. The data collected on the 18S ribosomal-RNA gene indicate that the snails investigated may cover more than one supraspecific taxon. The ITS-2, ITS-1 and COI nucleotide sequences are clearly useful markers for the differentiation of these morpho-anatomically similar lymnaeid species. The numerous microsatellite repeats found within ITS-2 are potential tools for differentiation at population level.

  3. Seed Transmission of Pseudoperonospora cubensis

    PubMed Central

    Cohen, Yigal; Rubin, Avia E.; Galperin, Mariana; Ploch, Sebastian; Runge, Fabian; Thines, Marco

    2014-01-01

    Pseudoperonospora cubensis, an obligate biotrophic oomycete causing devastating foliar disease in species of the Cucurbitaceae family, was never reported in seeds or transmitted by seeds. We now show that P. cubensis occurs in fruits and seeds of downy mildew-infected plants but not in fruits or seeds of healthy plants. About 6.7% of the fruits collected during 2012–2014 have developed downy mildew when homogenized and inoculated onto detached leaves and 0.9% of the seeds collected developed downy mildew when grown to the seedling stage. This is the first report showing that P. cubensis has become seed-transmitted in cucurbits. Species-specific PCR assays showed that P. cubensis occurs in ovaries, fruit seed cavity and seed embryos of cucurbits. We propose that international trade of fruits or seeds of cucurbits might be associated with the recent global change in the population structure of P. cubensis. PMID:25329308

  4. Genetic and pathogenic relatedness of Pseudoperonospora cubensis and P. humuli

    USDA-ARS?s Scientific Manuscript database

    The most economically important plant pathogens in the genus Pseudoperonospora (Peronosporaceae) are P. cubensis and P. humuli, causal agents of downy mildew on cucurbits and hop, respectively. Recently, P. humuli was reduced to a taxonomic synonym of P. cubensis based on internal transcribed spacer...

  5. Field response of cucurbit hosts to Pseudoperonospora cubensis in Michigan

    USDA-ARS?s Scientific Manuscript database

    Downy mildew, caused by Pseudoperonospora cubensis, is a severe foliar disease of many cucurbit crops worldwide. Forty-one cucurbit cultigens (commercial cultivars and plant introductions) from five genera (Cucumis, Citrullus, Cucurbita, Lagenaria, and Luffa) were assessed for susceptibility to Ps....

  6. mRNA-Seq Analysis of the Pseudoperonospora cubensis Transcriptome During Cucumber (Cucumis sativus L.) Infection

    PubMed Central

    Hamilton, John P.; Vaillancourt, Brieanne; Buell, C. Robin; Day, Brad

    2012-01-01

    Pseudoperonospora cubensis, an oomycete, is the causal agent of cucurbit downy mildew, and is responsible for significant losses on cucurbit crops worldwide. While other oomycete plant pathogens have been extensively studied at the molecular level, Ps. cubensis and the molecular basis of its interaction with cucurbit hosts has not been well examined. Here, we present the first large-scale global gene expression analysis of Ps. cubensis infection of a susceptible Cucumis sativus cultivar, ‘Vlaspik’, and identification of genes with putative roles in infection, growth, and pathogenicity. Using high throughput whole transcriptome sequencing, we captured differential expression of 2383 Ps. cubensis genes in sporangia and at 1, 2, 3, 4, 6, and 8 days post-inoculation (dpi). Additionally, comparison of Ps. cubensis expression profiles with expression profiles from an infection time course of the oomycete pathogen Phytophthora infestans on Solanum tuberosum revealed similarities in expression patterns of 1,576–6,806 orthologous genes suggesting a substantial degree of overlap in molecular events in virulence between the biotrophic Ps. cubensis and the hemi-biotrophic P. infestans. Co-expression analyses identified distinct modules of Ps. cubensis genes that were representative of early, intermediate, and late infection stages. Collectively, these expression data have advanced our understanding of key molecular and genetic events in the virulence of Ps. cubensis and thus, provides a foundation for identifying mechanism(s) by which to engineer or effect resistance in the host. PMID:22545137

  7. Speed of back-swimming of Lymnaea.

    PubMed

    Aono, Kanako; Fusada, A; Fusada, Y; Ishii, W; Kanaya, Y; Komuro, Mami; Matsui, Kanae; Meguro, S; Miyamae, Ayumi; Miyamae, Yurie; Murata, Aya; Narita, Shizuka; Nozaka, Hiroe; Saito, Wakana; Watanabe, Ayumi; Nishikata, Kaori; Kanazawa, A; Fujito, Y; Okada, R; Lukowiak, K; Ito, E

    2008-01-01

    The pond snail, Lymnaea stagnalis, can locomote on its back utilizing the surface tension of the water. We have called this form of movement 'back-swimming'. In order to perform this behavior, the snail must flip itself over on its back so that its foot is visible from above. Little is known about the mechanism of this back-swimming. As a first step for the elucidation of this mechanism, we measured the speed of back-swimming of Lymnaea at the different times of the day. They back-swam significantly faster in the morning than just before dark. These data are consistent with our earlier findings on circadian-timed activity pattern in Lymnaea. Lymnaea appear to secrete a thin membrane-like substance from their foot that may allow them to back-swim. To confirm the existence of this substance and to examine whether this substance is hydrophobic or hydrophilic, we applied a detergent onto the foot during back-swimming. A single drop of 1% Tween 20 drifted Lymnaea away that were still kept at the water surface. These results suggest that Lymnaea secrete a hydrophobic substance from their foot that floats to the water surface allowing Lymnaea to back-swim.

  8. Molecular approaches for biosurveillance of the cucurbit downy mildew pathogen, Pseudoperonospora cubensis

    USDA-ARS?s Scientific Manuscript database

    Globalization has allowed for rapid movement of plant pathogens that threaten food security. Successful disease management largely depends in timely and accurate detection of plant pathogens causing epidemics. Thus, biosurveillance of epidemic plant pathogens such as Pseudoperonospora cubensis, the ...

  9. Using Next-Generation Sequencing to Develop Molecular Diagnostics for Pseudoperonospora cubensis, the Cucurbit Downy Mildew Pathogen.

    PubMed

    Withers, S; Gongora-Castillo, E; Gent, D; Thomas, A; Ojiambo, P S; Quesada-Ocampo, L M

    2016-10-01

    Advances in next-generation sequencing (NGS) allow for rapid development of genomics resources needed to generate molecular diagnostics assays for infectious agents. NGS approaches are particularly helpful for organisms that cannot be cultured, such as the downy mildew pathogens, a group of biotrophic obligate oomycetes that infect crops of economic importance. Unlike most downy mildew pathogens that are highly host-specific, Pseudoperonospora cubensis causes disease on a broad range of crops belonging to the family Cucurbitaceae. In this study, we identified candidate diagnostic markers for P. cubensis by comparing NGS data from a diverse panel of P. cubensis and P. humuli isolates, two very closely related oomycete species. P. cubensis isolates from diverse hosts and geographical regions in the United States were selected for sequencing to ensure that candidates were conserved in P. cubensis isolates infecting different cucurbit hosts. Genomic regions unique to and conserved in P. cubensis isolates were identified through bioinformatics. These candidate regions were then validated using PCR against a larger collection of isolates from P. cubensis, P. humuli, and other oomycetes. Overall seven diagnostic markers were found to be specific to P. cubensis. These markers could be used for pathogen diagnostics on infected tissue, or adapted for monitoring airborne inoculum with real-time PCR and spore traps.

  10. Effects of Tarantula cubensis D6 on aflatoxin-induced injury in biochemical parameters in rats.

    PubMed

    Karabacak, Mürsel; Eraslan, Gökhan; Kanbur, Murat; Sarıca, Zeynep Soyer

    2015-07-01

    Aflatoxins are toxic fungal metabolites that have adverse effects on humans and animals. Tarantula cubensis D6 is used as a homeopathic medicine for different purposes. The present study investigates the effects of Tarantula cubensis D6 on the oxidant-antioxidant balance and some biochemical parameters against exposure to aflatoxin. Thirty-two Sprague-Dawley female rats were used and evenly divided into four groups. Group 1 served as control. Groups 2, 3, and 4 received 200 μl/kg.bw/day Tarantula cubensis D6 (applied subcutaneously), 400 μg/kg.bw/day total aflatoxin (approximately 80% AF B1, 10% AF B2, 6 %AF G1, and 4% AF G2), and 200 μl/kg.bw/day Tarantula cubensis D6 plus 400 μg/kg.bw/day total aflatoxin, respectively, for 28 days. At the end of 28 days, blood samples and some organs (liver, kidney, brain, and spleen) were taken from all the animals. Oxidative stress markers (MDA, SOD, CAT, GSH-Px) and some biochemical parameters (glucose, triglyceride, cholesterol, BUN, creatinine, AST, ALT and ALP, total protein, albumin) were evaluated in blood samples and tissues. Aflatoxin caused negative changes in all oxidative stress parameters and some biochemical parameters (glucose, triglyceride, cholesterol, creatinine, AST, ALT, ALP, total protein, albumin). Administration of Tarantula cubensis D6 partly alleviated aflatoxin-induced negative changes. Our results indicated that Tarantula cubensis D6 partially neutralized the deleterious effects of aflatoxin. Copyright © 2015 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

  11. Resurgence of Pseudoperonospora cubensis: The Causal Agent of Cucurbit Downy Mildew.

    PubMed

    Cohen, Yigal; Van den Langenberg, Kyle M; Wehner, Todd C; Ojiambo, Peter S; Hausbeck, Mary; Quesada-Ocampo, Lina M; Lebeda, Aleš; Sierotzki, Helge; Gisi, Ulrich

    2015-07-01

    The downy mildew pathogen, Pseudoperonospora cubensis, which infects plant species in the family Cucurbitaceae, has undergone major changes during the last decade. Disease severity and epidemics are far more destructive than previously reported, and new genotypes, races, pathotypes, and mating types of the pathogen have been discovered in populations from around the globe as a result of the resurgence of the disease. Consequently, disease control through host plant resistance and fungicide applications has become more complex. This resurgence of P. cubensis offers challenges to scientists in many research areas including pathogen biology, epidemiology and dispersal, population structure and population genetics, host preference, host-pathogen interactions and gene expression, genetic host plant resistance, inheritance of host and fungicide resistance, and chemical disease control. This review serves to summarize the current status of this major pathogen and to guide future management and research efforts within this pathosystem.

  12. The effects of Tarantula cubensis venom on open wound healing in rats.

    PubMed

    Gul Satar, N Y; Cangul, I T; Topal, A; Kurt, H; Ipek, V; Onel, G I

    2017-02-02

    The aim of this study was to evaluate the clinical and histopathological effects of two different dosages of alcohol extract of Tarantula cubensis (Theranekron) on open wounds. A total of 24 Sprague-Dawley rats were randomly divided into Tarantula cubensis extract (TCE1, n=8) 1/10 diluted, TCE (TCE2, n=8), and (3) vehicle-control (0.2 ml of 96 % ethanol, n=8) groups. Experimental full-thickness 1 x 1cm wounds were created on dorsum skin. TCE or vehicle were given systemically by subcutaneous injections on postoperative days 1 and 4. Wound planimetry and procurement of biopsies was performed on days 4, 8, 12 and 16. The mean non-epithelialised wound area in the vehicle-control group was significantly larger than in the TCE1 group on days 4, 8, 12 and 16, and in the TCE2 group on days 8, 12 and 16 (p<0.05). The mean percentage of wound contraction was significantly higher in the TCE1 and TCE2 groups than in the vehicle control group on days 8, 12 and 16 (p<0.05). Histopathologically, wound healing was characterised by a significant decrease in the neutrophil counts and a significant increase in neovascularisation; neither were effected by TCE. Our results suggest that alcohol extract of Tarantula cubensis accelerates epithelialisation and, thus, has beneficial effects on open wound healing in rats.

  13. Identification of genetic variation between obligate plant pathogens Psuedoperonospora cubensis and P. humuli using RNA sequencing and genotyping-by-sequencing

    USDA-ARS?s Scientific Manuscript database

    RNA sequencing (RNA-seq) and genotyping-by-sequencing (GBS) were used for single nucleotide polymorphism (SNP) identification from two economically important obligate plant pathogens, Pseudoperonospora cubensis and P. humuli. Twenty isolates of P. cubensis and 19 isolates of P. humuli were genotyped...

  14. Ecological observations on Lymnaea (Bullastra) cumingiana.

    PubMed

    Monzon, R B; Kitikoon, V; Thammapalerd, N; Temcharoen, P; Sornmani, S; Viyanant, V

    1993-09-01

    Field surveys conducted at Echague, Isabela and San Pablo, Laguna revealed that Lymnaea (Bullastra) cumingiana, the natural second snail intermediate host of Echinostoma malayanum in the Philippines, exhibits a moderate degree of diversity in its choice of habitats. Rice fields of all stages of development, stagnant shallow streams and springs are the main areas where the snail can be collected from at Echague, Isabela. However, they were absent in rice fields that had been extensively sprayed with molluscicides to control the "golden apple snail" (Ampullarius canaliculatus). In contrast, they were also very abundant in the highly eutrophic waters of Sampaloc lake, San Pablo, Laguna. L. cumingiana co-exists with various species of insects, snails, fish and plants in these habitats. Information on ecological characteristics affecting its distribution will be useful for those who wish to collect and study this species in the future.

  15. Fasciola hepatica in Cuba: compatibility of different isolates with two intermediate snail hosts, Galba cubensis and Pseudosuccinea columella.

    PubMed

    Vázquez, A A; Sánchez, J; Pointier, J-P; Théron, A; Hurtrez-Boussès, S

    2014-12-01

    In Cuba, only two lymnaeid snails, Galba cubensis and Pseudosuccinea columella, with different ecology and distribution patterns, are intermediate hosts for Fasciola hepatica. The compatibility of these two species as hosts was analysed through their rates of infection, the production of rediae and survivorship when exposed to F. hepatica miracidia. Ten populations of G. cubensis, eight of P. columella collected from various habitats and six isolates of F. hepatica sampled in slaughterhouses from different localities were tested. Our results clearly demonstrate that G. cubensis is a more compatible host for F. hepatica in Cuba when compared with P. columella. However, the role that P. columella may have in fascioliasis transmission under certain conditions should not be disregarded. Variation in infectivity among isolates of F. hepatica were also observed and may explain why some regions in Cuba are more commonly subjected to fascioliasis outbreaks.

  16. PCR diagnosis of Fasciola hepatica in field-collected Lymnaea columella and Lymnaea viatrix snails.

    PubMed

    Cucher, Marcela A; Carnevale, Silvana; Prepelitchi, Lucila; Labbé, Jorge H; Wisnivesky-Colli, Cristina

    2006-04-15

    Fasciolosis, caused by the trematode Fasciola hepatica, is a zoonosis of economic importance in livestock that is emerging as a chronic disease in humans. The intermediate hosts are lymnaeid snails, in which diagnosis of infection is traditionally based on cercarial shedding, tissue sectioning and crushing. We developed a PCR assay for the sensitive and specific detection of F. hepatica in field-collected Lymnaea sp. snails. A primer pair was designed to amplify a 405 bp fragment of the cytochrome c oxidase subunit 1 gene of F. hepatica. The PCR assay showed a limit of detection of 10 pg of genomic F. hepatica DNA. No cross-reactions were observed with samples from other related trematode species or from the snail hosts Lymnaea columella and Lymnaea viatrix. DNA sequencing of the amplicon showed 100% homology with F. hepatica, and 75-89% homology with other trematodes on regions that did not include the entire set of primers. Two samples from Argentina were analysed. For snails in sample 1 (n = 240), identified as L. columella, the infection rate was 17.5 and 51.3% by direct examination and PCR, respectively. For snails in sample 2 (n = 34), identified as L. viatrix, the infection rate was 2.9 and 61.8% by direct examination and PCR, respectively. Differences in infection rates between these diagnosis methods were significant for both samples. Our PCR technique showed to be effective for detecting specific F. hepatica infections of low intensity in the intermediate host, and hence it could be used to study the epidemiological situation in a given area, as well as to assess host suitability for the parasite.

  17. [Anatomy and morphometry of Physa cubensis Pfeiffer, 1839 (Pulmonata: Physidae) in Cuba].

    PubMed

    Cong, M Y; Ferrer López, J R; Perera de Puga, G

    1994-01-01

    The anatomic description of Physa cubensis, based on specimens collected in 5 different sites in Cuba, is presented. The anatomic characteristics of the reproductive system as well as mantle digitations give ground for affirming that this is a unique species with external morphological variations and thus it should be kept under the Physa genre. Besides, dispersion diagrams and regression lines of the length in the width were analyzed in the five sites; the L/A (length/width) variation quotient was compared using a variance analysis. Significant differences were observed in the different sites probably due to the feeding sources of each biotope.

  18. Virulence Structure Within Populations of Pseudoperonospora cubensis in the United States.

    PubMed

    Thomas, Anna; Carbone, Ignazio; Lebeda, Aleš; Ojiambo, Peter S

    2017-06-01

    Cucurbit downy mildew (CDM), caused by the obligate oomycete Pseudoperonospora cubensis, has resurged around the world during the past three decades. A new pathotype or genetic recombinant of P. cubensis have been suggested as possible reasons for the resurgence of CDM in the United States in 2004. In total, 22 isolates collected between 2004 and 2014, mainly in the eastern United States, were tested for their compatibility with a set of 15 cucurbit host types. The virulence structure within these isolates was evaluated on a set of 12 differential genotypes from eight genera. All isolates were highly compatible with the susceptible cultivar of Cucumis sativus, whereas the least compatibility was observed with Luffa cylindrica and Momordica charantia. Based on the compatibility with the differential host set, five pathotypes (1, 3, 4, 5, and 6) were identified among the 22 isolates examined. Pathotypes 1 and 3 had not been previously described in the United States and isolates of these two new pathotypes were also compatible with 'Poinsett 76', a cultivar of C. sativus known to be resistant to CDM prior to 2004. Virulence within the pathogen population was expressed based on virulence factors, virulence phenotypes, and virulence complexity. The number of virulence factors ranged from two to eight, indicating a complex virulence structure, with 77% of the isolates having five to eight virulence factors. Thirteen virulence phenotypes were identified; the mean number of virulence factors per isolate and mean number of virulence factors per virulence phenotype was 5.05 and 5.23, respectively, indicating that complex isolates and phenotypes contributed equally to the complex virulence structure of P. cubensis. Gleason and Shannon indices of diversity were 3.88 and 2.32, respectively, indicating a diverse virulence structure of P. cubensis within the United States population. The diverse virulence and high virulence complexity within the pathogen population indicate that

  19. Octopamine: a new feeding modulator in Lymnaea

    PubMed Central

    Vehovszky, Á.

    1998-01-01

    The role of octopamine (OA) in the feeding system of the pond snail, Lymnaea stagnalis, was studied by applying behavioural tests on intact animals, and a combination of electrophysiological analysis and morphological labelling in the isolated central nervous system. OA antagonists phentolamine, demethylchlordimeform (DCDM) and 2-chloro-4-methyl-2-(phenylimino)-imidazolidine (NC-7) were injected into intact snails and the sucrose-induced feeding response of animals was monitored. Snails that received 25 to 50 mg kg-1 phentolamine did not start feeding in sucrose, and the same dose of NC-7 reduced the number of feeding animals by 80 to 90% 1 to 3 hours after injection. DCDM treatment reduced feeding by 20 to 60%. In addition, both phentolamine and NC-7 significantly decreased the feeding rate of those animals that still accepted food after 1 to 6 hours of injection. In the central nervous system a pair of buccal neurons was identified by electrophysiological and morphological criteria. After double labelling (intracellular staining with Lucifer yellow followed by OA-immunocytochemistry) these neurons were shown to be OA immunoreactive, and electrophysiological experiments confirmed that they are members of the buccal feeding system. Therefore the newly identified buccal neurons were called OC neurons (putative octopamine containing neurons or octopaminergic cells). Synchronous intracellular recordings demonstrated that the OC neurons share a common rhythm with feeding neurons either appearing spontaneously or evoked by intracellularly stimulated feeding interneurons. OC neurons also have synaptic connections with identified members of the feeding network: electrical coupling was demonstrated between OC neurons and members of the B4 cluster motoneurons, furthermore, chemically transmitted synaptic responses were recorded both on feeding motoneurons (B1, B2 cells) and the SO modulatory interneuron after the stimulation of OC neurons. However, elementary synaptic

  20. Pseudoperonospora cubensis and P. humuli detection using species-specific probes and high definition melt curve analysis

    USDA-ARS?s Scientific Manuscript database

    Three assays were developed for molecular differentiation of Pseudoperonospora cubensis and P. humuli, causal agents of cucurbit and hop downy mildew, respectively, for detection of airborne sporangia and diagnosis of symptomatic leaf tissue. The assays were based on previously identified single nuc...

  1. Control of downy mildew (Pseudoperonospora cubensis) of greenhouse grown cucumbers with alternative biological agents.

    PubMed

    Scherf, A; Schuster, C; Marx, P; Gärber, U; Konstantinidou-Doltsinis, S; Schmitt, A

    2010-01-01

    In organic cucumber production infection with downy mildew (Pseudoperonospora cubensis) is a major problem. Plant extracts from Glycyrrhiza glabra L. (licorice), a plant belonging to the family Fabaceae, and Salvia officinalis (sage) as well as cultures of the bacterium Aneurinibacillus migulanus were investigated for efficacy of disease control under commercial growing conditions. Contrary to bioassays, where sage extract and the microorganism showed highest activity, in the trials of 2008 G. glabra extract was more effective than sage extract or A. migulanus against P. cubensis. Parameters such as concentrations of the preparations or application intervals could have been the reason for this. In the following year's trial (2009) the concentration of these agents was therefore increased somewhat and plants were either treated in seven day application intervals or in ten day application intervals. In the semi-commercial trials of 2009 all alternative biological agents showed good efficacies up to around 80% against infection with downy mildew. The application interval seemed to have a marginal effect only. Again, the licorice extract tended to be the best agent.

  2. The effect of particle size on the leaching of Scirpus cubensis Poepp & Kunth.

    PubMed

    Bianchini Júnior, I; Antonio, R M

    2003-05-01

    An investigation was made on the effects of detritus particle size on leaching rates in organic matter, and the associated environmental changes caused by detritus re-cycling in an oxbow lake (Lagoa do Infernão). Experiments were conducted during the decay of an aquatic macrophyte specie, S. cubensis, which in turn led to the formation of colored compounds. The S. cubensis were collected from the Lagoa do Infernão and taken to the laboratory where they were washed, dried, and fractionated using a sieve pedological set. The detritus was classified into six groups according to size, viz. 100, 10, 1.13, 0.78, 0.61, and 0.25 mm. Overall, the fragmentation process tended to increase the detritus fraction to be dissolved and to decrease the leaching rates owing to the possible dissolution of refracting matter. Fragmentation also caused the amount of colored compounds to increase and appeared to favor dissolved electrolyte release. Finally, in Lagoa do Infernão fragmentation is probably mediated by the metabolic action of benthic communities.

  3. Central Localization of Plasticity Involved in Appetitive Conditioning in "Lymnaea"

    ERIC Educational Resources Information Center

    Straub, Volko A.; Styles, Benjamin J.; Ireland, Julie S.; O'Shea, Michael; Benjamin, Paul R.

    2004-01-01

    Learning to associate a conditioned (CS) and unconditioned stimulus (US) results in changes in the processing of CS information. Here, we address directly the question whether chemical appetitive conditioning of "Lymnaea" feeding behavior involves changes in the peripheral and/or central processing of the CS by using extracellular recording…

  4. Central Localization of Plasticity Involved in Appetitive Conditioning in "Lymnaea"

    ERIC Educational Resources Information Center

    Straub, Volko A.; Styles, Benjamin J.; Ireland, Julie S.; O'Shea, Michael; Benjamin, Paul R.

    2004-01-01

    Learning to associate a conditioned (CS) and unconditioned stimulus (US) results in changes in the processing of CS information. Here, we address directly the question whether chemical appetitive conditioning of "Lymnaea" feeding behavior involves changes in the peripheral and/or central processing of the CS by using extracellular recording…

  5. Occurrence and Distribution of Mating Types of Pseudoperonospora cubensis in the United States.

    PubMed

    Thomas, Anna; Carbone, Ignazio; Cohen, Yigal; Ojiambo, Peter S

    2017-03-01

    During the past two decades, a resurgence of cucurbit downy mildew has occurred around the world, resulting in severe disease epidemics. In the United States, resurgence of the disease occurred in 2004 and several hypotheses, including introduction of a new genetic recombinant or pathotype of the pathogen, have been suggested as potential causes for this resurgence. Occurrence and distribution of mating types of Pseudoperonospora cubensis in the United States were investigated using 40 isolates collected from cucurbits across 11 states from 2005 to 2013. Pairing of unknown isolates with known mating-type tester strains on detached leaves of cantaloupe or cucumber resulted in oospore formation 8 to 10 days after inoculation. Isolates differed in their ability to form oospores across all coinoculation pairings, with oospore numbers ranging from 280 to 1,000 oospores/cm(2) of leaf tissue. Oospores were hyaline to golden-yellow, spherical, and approximately 36 μm in diameter. Of the 40 isolates tested, 24 were found to be of the A1 mating type, while 16 were of the A2 mating type. Mating type was significantly (P < 0.0001) associated with host type, whereby all isolates collected from cucumber were of the A1 mating type, while isolates from squash and watermelon were of the A2 mating type. Similarly, mating type was significantly (P = 0.0287) associated with geographical region, where isolates from northern-tier states of Michigan, New Jersey, New York, and Ohio were all A1, while isolates belonging to either A1 or A2 mating type were present in equal proportions in southern-tier states of Alabama, Florida, Georgia, North Carolina, South Carolina, and Texas. Viability assays showed that oospores were viable and, on average, approximately 40% of the oospores produced were viable as determined by the plasmolysis method. This study showed that A1 and A2 mating types of P. cubensis are present and the pathogen could potentially reproduce sexually in cucurbits within the

  6. Epidemiology and population biology of Pseudoperonospora cubensis: a model system for management of downy mildews.

    PubMed

    Ojiambo, Peter S; Gent, David H; Quesada-Ocampo, Lina M; Hausbeck, Mary K; Holmes, Gerald J

    2015-01-01

    The resurgence of cucurbit downy mildew has dramatically influenced production of cucurbits and disease management systems at multiple scales. Long-distance dispersal is a fundamental aspect of epidemic development that influences the timing and extent of outbreaks of cucurbit downy mildew. The dispersal potential of Pseudoperonospora cubensis appears to be limited primarily by sporangia production in source fields and availability of susceptible hosts and less by sporangia survival during transport. Uncertainty remains regarding the role of locally produced inoculum in disease outbreaks, but evidence suggests multiple sources of primary inoculum could be important. Understanding pathogen diversity and population differentiation is a critical aspect of disease management and an active research area. Underpinning advances in our understanding of pathogen biology and disease management has been the research capacity and coordination of stakeholders, scientists, and extension personnel. Concepts and approaches developed in this pathosystem can guide future efforts when responding to incursions of new or reemerging downy mildew pathogens.

  7. A multiplex PCR for the detection of Fasciola hepatica in the intermediate snail host Galba cubensis.

    PubMed

    Alba, Annia; Vázquez, Antonio A; Hernández, Hilda; Sánchez, Jorge; Marcet, Ricardo; Figueredo, Mabel; Sarracent, Jorge; Fraga, Jorge

    2015-07-30

    Fasciolosis is a snail-borne trematode infection that has re-emerged as a human disease, and is considered a significant problem for veterinary medicine worldwide. The evaluation of the transmission risk of fasciolosis as well as the efficacy of the strategies for its control could be carried out through epidemiological surveillance of the snails that act as intermediate hosts of the parasites. The present study aimed to develop the first multiplex PCR to detect Fasciola hepatica in Galba cubensis, an important intermediate host of the parasite in the Americas and especially in the Caribbean basin. The multiplex PCR was optimized for the amplification of a 340 bp fragment of the second internal transcribed spacer (ITS-2) of F. hepatica rDNA, while another set of primers was designed and used to amplify a conserved segment of the nuclear 18S rDNA of the snail (451 bp), as an internal control of the reaction. The assay was able to detect up to 100 pg of the parasite even at high concentrations of snail DNA, an analytical sensitivity that allows the detection of less than a single miracidium, which is the minimal biological infestation unit. A controlled laboratory-reared G. cubensis - F. hepatica system was used for the evaluation of the developed multiplex PCR, and 100% sensitivity and specificity was achieved. This assay constitutes a novel, useful and suitable technique for the survey of fasciolosis transmission through one of the main intermediate hosts in the Western hemisphere. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Pharmacological effects of cannabinoids on learning and memory in Lymnaea.

    PubMed

    Sunada, Hiroshi; Watanabe, Takayuki; Hatakeyama, Dai; Lee, Sangmin; Forest, Jeremy; Sakakibara, Manabu; Ito, Etsuro; Lukowiak, Ken

    2017-09-01

    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. © 2017. Published by The Company of Biologists Ltd.

  9. The effect of Psilocybe cubensis extract on hippocampal neurons in vitro.

    PubMed

    Moldavan, M G; Grodzinskaya, A A; Solomko, E F; Lomberh, M L; Wasser, S P; Storozhuk, V M

    2001-01-01

    The action of P. cubensis mushroom extract, containing psilocybin (PCB) and psilocin, on spike activity of hippocampal CA1 pyramidal neurons was studied in in vitro rat brain slices. In 38 (76%) out of 50 investigated neurons spike activity was decreased, in 2 (4%) cells it increased. There was no response 10 (20%) neurons. Application of the extract caused short burst firing in 12 (24%) neurons. All neurons showing inhibition during PCB-containing extract application, were also inhibited by serotonin (5-HT). Usually inhibitory reaction did not last over 4-5 min upon 3 min extract application and could be prolonged up to 10-43 min up on serotonin application. Part of neurons were inhibited by serotonin and did not react to extract application. Inhibitory reactions induced by extract application were blocked by ritanserin in half of the tested units and were induced due to activation of 5-HT2 serotonin receptors. The extract suppressed excitative spike reactions caused by application of L-glutamic acid. It is concluded, that application of PCB-containing extract in most cases reduced spike activity in hippocampal CA1 pyramidal neurons and suppressed glutamate transmission.

  10. Expression profiling of Cucumis sativus in response to infection by Pseudoperonospora cubensis.

    PubMed

    Adhikari, Bishwo N; Savory, Elizabeth A; Vaillancourt, Brieanne; Childs, Kevin L; Hamilton, John P; Day, Brad; Buell, C Robin

    2012-01-01

    The oomycete pathogen, Pseudoperonospora cubensis, is the causal agent of downy mildew on cucurbits, and at present, no effective resistance to this pathogen is available in cultivated cucumber (Cucumis sativus). To better understand the host response to a virulent pathogen, we performed expression profiling throughout a time course of a compatible interaction using whole transcriptome sequencing. As described herein, we were able to detect the expression of 15,286 cucumber genes, of which 14,476 were expressed throughout the infection process from 1 day post-inoculation (dpi) to 8 dpi. A large number of genes, 1,612 to 3,286, were differentially expressed in pair-wise comparisons between time points. We observed the rapid induction of key defense related genes, including catalases, chitinases, lipoxygenases, peroxidases, and protease inhibitors within 1 dpi, suggesting detection of the pathogen by the host. Co-expression network analyses revealed transcriptional networks with distinct patterns of expression including down-regulation at 2 dpi of known defense response genes suggesting coordinated suppression of host responses by the pathogen. Comparative analyses of cucumber gene expression patterns with that of orthologous Arabidopsis thaliana genes following challenge with Hyaloperonospora arabidopsidis revealed correlated expression patterns of single copy orthologs suggesting that these two dicot hosts have similar transcriptional responses to related pathogens. In total, the work described herein presents an in-depth analysis of the interplay between host susceptibility and pathogen virulence in an agriculturally important pathosystem.

  11. Alcoholic extract of tarantula cubensis improves sharp ruptured tendon healing after primary repair in rabbits.

    PubMed

    Oryan, Ahmad; Moshiri, Ali; Meimandi Parizi, Abdolhamid

    2012-12-01

    This study was designed to investigate the effects of tarantula cubensis (TC) on the superficial digital flexor tendon (SDFT) rupture after surgical anastomosis, on day 84-postinjury (DPI) in rabbits. Forty white New Zealand, mature, male rabbits were randomly and evenly divided into treated and control groups. After tenotomy and primary repair, the injured legs were immobilized for 2 weeks. TC was injected subcutaneously over the lesion on 3, 7, and 10 DPI. The control animals received subcutaneous injections of normal saline similarly. Animal's weight, tendon diameter, clinical status, radiographic and ultrasonographic evaluations were recorded at weekly intervals. The animals were euthanized on 84 DPI and the injured tendons and their normal contralaterals were evaluated for histopathologic, histomorphometric, ultrastructural, biomechanical, and percentage dry weight parameters. Treatment significantly improved the clinical performance, cell, collagen and tissue maturation, tissue alignment and remodeling, ultimate strength, stiffness, maximum stress, and dry weight content and decreased the tendon diameter, inflammation, adhesions and degeneration of the injured treated tendons compared to the injured control ones. The present findings showed that TC is effective on sharp ruptured SDFT in rabbits and it could be one of the novel therapeutic options in clinical trial studies.

  12. Tarantula cubensis extract alters the degree of apoptosis and mitosis in canine mammary adenocarcinomas.

    PubMed

    Gultiken, Nilgun; Guvenc, Tolga; Kaya, Duygu; Agaoglu, Ali Reha; Ay, Serhan Serhat; Kucukaslan, Ibrahim; Emre, Birten; Findik, Murat; Schäfer-Somi, Sabine; Aslan, Selim

    2015-01-01

    In the present study, 13 clinical cases of canine mammary adenocarcinoma were evaluated in order to understand the effect of Tarantula cubensis extract (TCE) on tumor tissue. Punch biopsies were taken from the tumors before treatment with TCE. Subcutaneous injections of TCE were administered three times at weekly intervals (3 mL per dog). Between days 7 and 10 after the third injection, the tumor masses were extirpated by complete unilateral mastectomy. Pre- and post-treatment tumor tissues were immunohistochemically assessed. The expression of B-cell lymphoma 2 (Bcl-2) was found to be higher in pre-treatment compared to post-treatment tissues (p < 0.01) whereas Ki-67 expression was lower in post-treatment tissues (p < 0.01). No significant differences in fibroblast growth factor or vascular endothelial growth factor expression were observed between pre- and post-treatment tissues (p > 0.05). The apoptotic index was determined to be low before treatment and increased during treatment. These results suggest that TCE may be effective for controlling the local growth of canine mammary adenocarcinoma by regulating apoptosis.

  13. Expression Profiling of Cucumis sativus in Response to Infection by Pseudoperonospora cubensis

    PubMed Central

    Vaillancourt, Brieanne; Childs, Kevin L.; Hamilton, John P.; Day, Brad; Buell, C. Robin

    2012-01-01

    The oomycete pathogen, Pseudoperonospora cubensis, is the causal agent of downy mildew on cucurbits, and at present, no effective resistance to this pathogen is available in cultivated cucumber (Cucumis sativus). To better understand the host response to a virulent pathogen, we performed expression profiling throughout a time course of a compatible interaction using whole transcriptome sequencing. As described herein, we were able to detect the expression of 15,286 cucumber genes, of which 14,476 were expressed throughout the infection process from 1 day post-inoculation (dpi) to 8 dpi. A large number of genes, 1,612 to 3,286, were differentially expressed in pair-wise comparisons between time points. We observed the rapid induction of key defense related genes, including catalases, chitinases, lipoxygenases, peroxidases, and protease inhibitors within 1 dpi, suggesting detection of the pathogen by the host. Co-expression network analyses revealed transcriptional networks with distinct patterns of expression including down-regulation at 2 dpi of known defense response genes suggesting coordinated suppression of host responses by the pathogen. Comparative analyses of cucumber gene expression patterns with that of orthologous Arabidopsis thaliana genes following challenge with Hyaloperonospora arabidopsidis revealed correlated expression patterns of single copy orthologs suggesting that these two dicot hosts have similar transcriptional responses to related pathogens. In total, the work described herein presents an in-depth analysis of the interplay between host susceptibility and pathogen virulence in an agriculturally important pathosystem. PMID:22545095

  14. Alternative Splicing of a Multi-Drug Transporter from Pseudoperonospora cubensis Generates an RXLR Effector Protein That Elicits a Rapid Cell Death

    PubMed Central

    Savory, Elizabeth A.; Zou, Cheng; Adhikari, Bishwo N.; Hamilton, John P.; Buell, C. Robin; Shiu, Shin-Han; Day, Brad

    2012-01-01

    Pseudoperonospora cubensis, an obligate oomycete pathogen, is the causal agent of cucurbit downy mildew, a foliar disease of global economic importance. Similar to other oomycete plant pathogens, Ps. cubensis has a suite of RXLR and RXLR-like effector proteins, which likely function as virulence or avirulence determinants during the course of host infection. Using in silico analyses, we identified 271 candidate effector proteins within the Ps. cubensis genome with variable RXLR motifs. In extending this analysis, we present the functional characterization of one Ps. cubensis effector protein, RXLR protein 1 (PscRXLR1), and its closest Phytophthora infestans ortholog, PITG_17484, a member of the Drug/Metabolite Transporter (DMT) superfamily. To assess if such effector-non-effector pairs are common among oomycete plant pathogens, we examined the relationship(s) among putative ortholog pairs in Ps. cubensis and P. infestans. Of 271 predicted Ps. cubensis effector proteins, only 109 (41%) had a putative ortholog in P. infestans and evolutionary rate analysis of these orthologs shows that they are evolving significantly faster than most other genes. We found that PscRXLR1 was up-regulated during the early stages of infection of plants, and, moreover, that heterologous expression of PscRXLR1 in Nicotiana benthamiana elicits a rapid necrosis. More interestingly, we also demonstrate that PscRXLR1 arises as a product of alternative splicing, making this the first example of an alternative splicing event in plant pathogenic oomycetes transforming a non-effector gene to a functional effector protein. Taken together, these data suggest a role for PscRXLR1 in pathogenicity, and, in total, our data provide a basis for comparative analysis of candidate effector proteins and their non-effector orthologs as a means of understanding function and evolutionary history of pathogen effectors. PMID:22496844

  15. Lymnaea palustris and Lymnaea fuscus are potential but uncommon intermediate hosts of Fasciola hepatica in Sweden

    PubMed Central

    2013-01-01

    Background Lymnaea palustris and L. fuscus are members of the European stagnicolines (Gastropoda: Lymnaeidae). The role of stagnicolines in transmission of Fasciola hepatica has been often proposed. To assess the possible relationship between these two stagnicolines and F. hepatica in Sweden, field monitoring in parallel with experimental infections of L. palustris and L. fuscus were conducted. Methods Stagnicoline snails were collected and identified on pastures grazed by either sheep or cattle on four farms suffering from fasciolosis in Sweden during 2011–2012. Field-collected L. palustris and L. fuscus were examined for F. hepatica DNA by PCR. In the laboratory, different age groups of L. palustris, L. fuscus and G. truncatula were each exposed to two F. hepatica miracidia and main infection characteristics were obtained. Results One field-collected L. palustris (out of n = 668) contained F. hepatica as determined by PCR. On the other hand, stagnicolines artificially exposed to F. hepatica miracidia resulted in successful infection with fully differentiated cercariae, but only in juvenile snails (size, 1–2 mm at exposure) and with a prevalence of 51% and 13% in L. palustris and L. fuscus, respectively. In contrast, 90% of juvenile (size, 1–2 mm) and 92% of preadult G. truncatula (size, ≥ 2-4 mm), respectively, were successfully infected. Delayed, reduced and/or no spontaneous cercarial shedding was observed in the two stagnicolines when compared to G. truncatula. However, at snail dissection most cercariae from L. fuscus and L. palustris were able to encyst similarly to those from G. truncatula. Conclusion Both L. fuscus and L. palustris can sustain larval development of F. hepatica but with an apparent level of age resistance. The finding of a single F. hepatica positive specimen of L. palustris, together with infection characteristics from the experimental infection, suggest that L. palustris is a more suitable snail vector of F. hepatica than L

  16. Lymnaea palustris and Lymnaea fuscus are potential but uncommon intermediate hosts of Fasciola hepatica in Sweden.

    PubMed

    Novobilský, Adam; Kašný, Martin; Beran, Luboš; Rondelaud, Daniel; Höglund, Johan

    2013-08-29

    Lymnaea palustris and L. fuscus are members of the European stagnicolines (Gastropoda: Lymnaeidae). The role of stagnicolines in transmission of Fasciola hepatica has been often proposed. To assess the possible relationship between these two stagnicolines and F. hepatica in Sweden, field monitoring in parallel with experimental infections of L. palustris and L. fuscus were conducted. Stagnicoline snails were collected and identified on pastures grazed by either sheep or cattle on four farms suffering from fasciolosis in Sweden during 2011-2012. Field-collected L. palustris and L. fuscus were examined for F. hepatica DNA by PCR. In the laboratory, different age groups of L. palustris, L. fuscus and G. truncatula were each exposed to two F. hepatica miracidia and main infection characteristics were obtained. One field-collected L. palustris (out of n = 668) contained F. hepatica as determined by PCR. On the other hand, stagnicolines artificially exposed to F. hepatica miracidia resulted in successful infection with fully differentiated cercariae, but only in juvenile snails (size, 1-2 mm at exposure) and with a prevalence of 51% and 13% in L. palustris and L. fuscus, respectively. In contrast, 90% of juvenile (size, 1-2 mm) and 92% of preadult G. truncatula (size, ≥ 2-4 mm), respectively, were successfully infected. Delayed, reduced and/or no spontaneous cercarial shedding was observed in the two stagnicolines when compared to G. truncatula. However, at snail dissection most cercariae from L. fuscus and L. palustris were able to encyst similarly to those from G. truncatula. Both L. fuscus and L. palustris can sustain larval development of F. hepatica but with an apparent level of age resistance. The finding of a single F. hepatica positive specimen of L. palustris, together with infection characteristics from the experimental infection, suggest that L. palustris is a more suitable snail vector of F. hepatica than L. fuscus. The reduced growth observed in both

  17. Which Morphological Characteristics Are Most Influenced by the Host Matrix in Downy Mildews? A Case Study in Pseudoperonospora cubensis

    PubMed Central

    Runge, Fabian; Ndambi, Beninweck; Thines, Marco

    2012-01-01

    Before the advent of molecular phylogenetics, species concepts in the downy mildews, an economically important group of obligate biotrophic oomycete pathogens, have mostly been based upon host range and morphology. While molecular phylogenetic studies have confirmed a narrow host range for many downy mildew species, others, like Pseudoperonospora cubensis affect even different genera. Although often morphological differences were found for new, phylogenetically distinct species, uncertainty prevails regarding their host ranges, especially regarding related plants that have been reported as downy mildew hosts, but were not included in the phylogenetic studies. In these cases, the basis for deciding if the divergence in some morphological characters can be deemed sufficient for designation as separate species is uncertain, as observed morphological divergence could be due to different host matrices colonised. The broad host range of P. cubensis (ca. 60 host species) renders this pathogen an ideal model organism for the investigation of morphological variations in relation to the host matrix and to evaluate which characteristics are best indicators for conspecificity or distinctiveness. On the basis of twelve morphological characterisitcs and a set of twelve cucurbits from five different Cucurbitaceae tribes, including the two species, Cyclanthera pedata and Thladiantha dubia, hitherto not reported as hosts of P. cubensis, a significant influence of the host matrix on pathogen morphology was found. Given the high intraspecific variation of some characteristics, also their plasticity has to be taken into account. The implications for morphological species determination and the confidence limits of morphological characteristics are discussed. For species delimitations in Pseudoperonospora it is shown that the ratio of the height of the first ramification to the sporangiophore length, ratio of the longer to the shorter ultimate branchlet, and especially the length and

  18. Distributed network organization underlying feeding behavior in the mollusk Lymnaea.

    PubMed

    Benjamin, Paul R

    2012-04-17

    The aim of the work reviewed here is to relate the properties of individual neurons to network organization and behavior using the feeding system of the gastropod mollusk, Lymnaea. Food ingestion in this animal involves sequences of rhythmic biting movements that are initiated by the application of a chemical food stimulus to the lips and esophagus. We investigated how individual neurons contribute to various network functions that are required for the generation of feeding behavior such as rhythm generation, initiation ('decision making'), modulation and hunger and satiety. The data support the view that feeding behavior is generated by a distributed type of network organization with individual neurons often contributing to more than one network function, sharing roles with other neurons. Multitasking in a distributed type of network would be 'economically' sensible in the Lymnaea feeding system where only about 100 neurons are available to carry out a variety of complex tasks performed by millions of neurons in the vertebrate nervous system. Having complementary and potentially alternative mechanisms for network functions would also add robustness to what is a 'noisy' network where variable firing rates and synaptic strengths are commonly encountered in electrophysiological recording experiments.

  19. Intermediate snail hosts of French Fasciola hepatica: Lymnaea neotropica and Lymnaea viatrix are better hosts than local Galba truncatula.

    PubMed

    Sanabria, R; Mouzet, R; Courtioux, B; Vignoles, P; Rondelaud, D; Dreyfuss, G; Cabaret, J; Romero, J

    2012-11-01

    Allopatric and sympatric infections of Lymnaea neotropica and Lymnaea viatrix var. ventricosa with Argentinean and French isolates of Fasciola hepatica were carried out to determine the capacity of these snails to produce metacercariae and to verify if this capacity changed with snail generation. The same process was also made with a French population of Galba truncatula known to be highly susceptible to French isolates of the parasite. In each lymnaeid species separately considered, the survival rate at day 30 post-exposure and prevalence of F. hepatica infection in the group infected with Argentinean miracidia were significantly greater than those recorded in the corresponding French one. Compared to infected G. truncatula, both South American lymnaeids had longer patent periods and produced a higher number of metacercariae. The highest infections were noted with L. v. ventricosa. In the three snail species, metacercarial production was more important with the Argentinean isolate of miracidia than with the French one. If three successive generations of L. v. ventricosa are exposed to the same French isolate of miracidia, cercarial production significantly increased from parents to the F2 generation, while the other characteristics of infection only showed insignificant variations. L. neotropica and L. v. ventricosa are better intermediate hosts for French F. hepatica than local G. truncatula. The numerical increase of shed cercariae in the F1 and F2 generations of L. v. ventricosa demonstrates a rapid adaptation of this species to the French isolate of the parasite.

  20. Characterization of pre- and postsynaptic dopamine receptors in Lymnaea.

    PubMed

    Audesirk, T E

    1989-01-01

    1. The effects of dopamine and several synthetic agonists and antagonists were studied using two identified neurons of the snail Lymnaea stagnalis. 2. In both the buccal-2 (B-2) neurons and the pedal giant (RPeD1) neuron dopamine elicited a hyperpolarizing response at least partly due to potassium efflux. RPeD1 is itself dopaminergic, implicating autoreceptors in its response to dopamine. 3. The following agents were tested: agonists--LY171555, pergolide, SKF38393, (-)-3-PPP, R(-)NPA and dopamine; antagonists--SCH23390, sulpiride, and metaclopramide. Dibutyryl cAMP was applied to determine whether the response is cAMP-mediated. 4. Results indicate that the pharmacological profiles of dopamine receptors on these neurons are inconsistent with those of either D-1, D-2 or autoreceptors in mammals.

  1. Copper toxicity to the fresh water snail, Lymnaea luteola

    SciTech Connect

    Reddy, N.M.; Rao, P.V.

    1987-07-01

    Haemocyanins are found in arthropoda and mollusca and show a copper content characteristic for each phylum. Heavy metal accumulation by mollusks is widely reported. Approximately one third of the enzymes either required addition of a metal ion as a cofactor in order to exhibit maximum activity or contained a slightly bound metal ion which appeared to be involved in the catalytic process. Copper is the only metal which has been detected in significant amounts in amino oxidase. The present study is designed to evaluate the influence of such copper, which is of such common occurrence in biological material, on some of the lipolytic enzymes of fresh water pulmonate snail, Lymnaea luteola when added to ambient medium. The present study also highlights the possible detoxification mechanism prevailing in this fresh water mollusk.

  2. Translocation of mercury from substrate to fruit bodies of Panellus stipticus, Psilocybe cubensis, Schizophyllum commune and Stropharia rugosoannulata on oat flakes.

    PubMed

    Gabriel, Jiří; Švec, Karel; Kolihová, Dana; Tlustoš, Pavel; Száková, Jiřina

    2016-03-01

    The cultivation and fructification of 15 saprotrophic and wood-rotting fungal strains were tested on three various semi-natural medium. The formation of fruit bodies was observed for Panellus stipticus, Psilocybe cubensis, Schizophyllum commune and Stropharia rugosoannulata in the frame of 1-2 months. Mercury translocation from the substrate to the fruit bodies was then followed in oat flakes medium. Translocation was followed for treatments of 0, 1.25, 2.5, 5, 10 and 20ppm Hg in the substrate. All four fungi formed fruit bodies in almost all replicates. The fruit body yield varied from 0.5 to 15.3g dry weight. The highest bioconcentration factor (BCF) of 2.99 was found for P. cubensis at 1.25ppm Hg. The BCF decreased with increasing Hg concentration in the substrate: 2.49, 0, 2.38, 1.71 and 1.82 for P. stipticus; 3.00, 2.78, 2.48, 1.81 and 2.15 for P. cubensis; 2.47, 1.81, 1.78, 1.07 and 0.96 for S. commune; and 1.96, 1.84, 1.21, 1.71 and 0.96 for S. rugosoannulata. The Hg contents in the fruit bodies reflected the Hg contents in the substrate; the highest contents in the fruit bodies were found in P. cubensis (43.08±7.36ppm Hg) and P. stipticus (36.42±3.39ppm). Copyright © 2015 Elsevier Inc. All rights reserved.

  3. The Novel Oomycide Oxathiapiprolin Inhibits All Stages in the Asexual Life Cycle of Pseudoperonospora cubensis - Causal Agent of Cucurbit Downy Mildew

    PubMed Central

    Cohen, Yigal

    2015-01-01

    Oxathiapiprolin is a new oomycide (piperidinyl thiazole isoxazoline class) discovered by DuPont which controls diseases caused by oomycete plant pathogens. It binds in the oxysterol-binding protein domain of Oomycetes. Growth chambers studies with detached leaves and potted plants showed remarkable activity of oxathiapiprolin against Pseudoperonospora cubensis in cucurbits. The compound affected all stages in the asexual life cycle of the pathogen. It inhibited zoospore release, cystospore germination, lesion formation, lesion expansion, sporangiophore development and sporangial production. When applied to the foliage as a preventive spray no lesions developed due to inhibition of zoospore release and cystospore germination, and when applied curatively, at one or two days after inoculation, small restricted lesions developed but no sporulation occurred. When applied later to mature lesions, sporulation was strongly inhibited. Oxathiapiprolin suppressed sporulation of P. cubensis in naturally-infected leaves. It exhibited trans-laminar activity, translocated acropetaly from older to younger leaves, and moved from the root system to the foliage. Seed coating was highly effective in protecting the developed cucumber plants against downy mildew. UV microscopy observations made with cucumber leaves infected with P. cubensis revealed that inhibition of mycelium growth and sporulation induced by oxathiapiprolin was associated with callose encasement of the haustoria. PMID:26452052

  4. Identification of Genetic Variation between Obligate Plant Pathogens Pseudoperonospora cubensis and P. humuli Using RNA Sequencing and Genotyping-By-Sequencing

    PubMed Central

    Summers, Carly F.; Gulliford, Colwyn M.; Carlson, Craig H.; Lillis, Jacquelyn A.; Carlson, Maryn O.; Cadle-Davidson, Lance; Gent, David H.; Smart, Christine D.

    2015-01-01

    RNA sequencing (RNA-seq) and genotyping-by-sequencing (GBS) were used for single nucleotide polymorphism (SNP) identification from two economically important obligate plant pathogens, Pseudoperonospora cubensis and P. humuli. Twenty isolates of P. cubensis and 19 isolates of P. humuli were genotyped using RNA-seq and GBS. Principle components analysis (PCA) of each data set showed genetic separation between the two species. Additionally, results supported previous findings that P. cubensis isolates from squash are genetically distinct from cucumber and cantaloupe isolates. A PCA-based procedure was used to identify SNPs correlated with the separation of the two species, with 994 and 4,231 PCA-correlated SNPs found within the RNA-seq and GBS data, respectively. The corresponding unigenes (n = 800) containing these potential species-specific SNPs were then annotated and 135 putative pathogenicity genes, including 3 effectors, were identified. The characterization of genes containing SNPs differentiating these two closely related downy mildew species may contribute to the development of improved detection and diagnosis strategies and improve our understanding of host specificity pathways. PMID:26599440

  5. Identification of Genetic Variation between Obligate Plant Pathogens Pseudoperonospora cubensis and P. humuli Using RNA Sequencing and Genotyping-By-Sequencing.

    PubMed

    Summers, Carly F; Gulliford, Colwyn M; Carlson, Craig H; Lillis, Jacquelyn A; Carlson, Maryn O; Cadle-Davidson, Lance; Gent, David H; Smart, Christine D

    2015-01-01

    RNA sequencing (RNA-seq) and genotyping-by-sequencing (GBS) were used for single nucleotide polymorphism (SNP) identification from two economically important obligate plant pathogens, Pseudoperonospora cubensis and P. humuli. Twenty isolates of P. cubensis and 19 isolates of P. humuli were genotyped using RNA-seq and GBS. Principle components analysis (PCA) of each data set showed genetic separation between the two species. Additionally, results supported previous findings that P. cubensis isolates from squash are genetically distinct from cucumber and cantaloupe isolates. A PCA-based procedure was used to identify SNPs correlated with the separation of the two species, with 994 and 4,231 PCA-correlated SNPs found within the RNA-seq and GBS data, respectively. The corresponding unigenes (n = 800) containing these potential species-specific SNPs were then annotated and 135 putative pathogenicity genes, including 3 effectors, were identified. The characterization of genes containing SNPs differentiating these two closely related downy mildew species may contribute to the development of improved detection and diagnosis strategies and improve our understanding of host specificity pathways.

  6. Effects of millimeter waves on ionic currents of Lymnaea neurons.

    PubMed

    Alekseev, S I; Ziskin, M C

    1999-01-01

    The effects of mm-waves 60.22-62.22 GHz and 75 GHz on A-type K+ currents and the effects of 61.22 GHz on Ca2+ currents of Lymnaea neurons were investigated using a whole-cell voltage-clamp technique. The open end of a rectangular waveguide covered with a thin Teflon film served as a radiator. Specific absorption rates at the waveguide outlet, inserted into physiological solution, were in the range of 0-2400 W/kg. Millimeter wave irradiation increased the peak amplitudes, activation rates, and inactivation rates of both ion currents. The changes in A-type K+ current were not dependent on the irradiation frequency. It was shown that the changes in the amplitudes and kinetics of both currents resulted from the temperature rise produced by irradiation. No additional effects of irradiation on A-type K+ current other than thermal were found when tested at the phase transition temperature or in the presence of ethanol. Ethanol reduced the thermal effect of irradiation. Millimeter waves had no effect on the steady-state activation and inactivation curves, suggesting that the membrane surface charge and binding of calcium ions to the membrane in the area of channel locations did not change.

  7. Susceptibility of two-week old Lymnaea natalensis to some plant extracts.

    PubMed

    Kela, S L; Ogunsusi, R A; Ogbogu, V C; Nwude, N

    1989-01-01

    The molluscacidal potency of 17 Nigerian plants extracted by the unevaporated crude water (UECW) method was evaluated on two-week old Lymnaea natalensis Krauss. Five extracts were not active but extracts of Balanites aegytiaca, Blighia sapida, Boswellia dalzielii, Cissampelos mucronata, Detarium microcarpum, Kigelia africana, Opilia celtidifolia, Parkia clappertoniana, Polygonum limbatum, Pseudocedrela kotschyi, Nauclea latifolia and Securidaca longipedunculata were molluscacidal. There is potential for their future use in the integrated control of Lymnaea natalensis, as well as other snails. Mortality data for lethal concentration values for all extracts were analysed by use of probit transformation. The upper and lower fiducial limits of the LC50 (P = 0.05) were also determined.

  8. Effect of the exposure to Fasciola hepatica (Trematoda: Digenea) on life history traits of Lymnaea cousini and Lymnaea columella (Gastropoda: Lymnaeidae).

    PubMed

    Salazar, Laura; Estrada, Victoria E; Velásquez, Luz E

    2006-10-01

    The snails Lymnaea columella and Lymnaea cousini have both been reported as intermediate hosts of Fasciola hepatica in Colombia. The effect of the exposure to the parasite on survival, fecundity and size of these snails was evaluated by means of experimental infections and the life history traits of control and exposed groups were compared. Infection rates were 82.2 and 34% for L. columella and L. cousini, respectively. A reduction in fitness was observed in both species when exposed to the parasite: fecundity alone was reduced in L. columella whereas in L. cousini there was also a decline in survival rate. Unlike other studies, increased size was not observed in either species. On the contrary, a reduction in growth rate was observed in L. columella.

  9. Predator detection enables juvenile Lymnaea to form long-term memory.

    PubMed

    Orr, M V; Hittel, K; Lukowiak, K

    2010-01-15

    Learning and memory provide the flexibility an organism requires to respond to changing social and ecological conditions. Juvenile Lymnaea have previously been shown to have a diminished capacity to form long-term memory (LTM) following operant conditioning of aerial respiratory behavior. Juvenile Lymnaea, however, can form LTM following classical conditioning of appetitive behaviors. Here, we demonstrate that laboratory-reared juvenile Lymnaea have the ability to detect the presence of a sympatric predator (i.e. crayfish) and respond to the predator by altering their aerial respiratory behavior. In addition to increasing their total breathing time, predator detection confers on juvenile Lymnaea an enhanced capability to form LTM following operant conditioning of aerial respiratory behavior. That is, these juveniles now have the ability to form long-lasting memory. These data support the hypothesis that biologically relevant levels of stress associated with predator detection induce behavioral phenotypic alterations (i.e. enhanced LTM formation) in juveniles, which may increase their fitness. These data also support the notion that learning and memory formation in conjunction with predator detection is a form of inducible defense.

  10. An octopaminergic system in the CNS of the snails, Lymnaea stagnalis and Helix pomatia

    PubMed Central

    Hiripi, L.

    1998-01-01

    Octopamine (OA) levels in each ganglion of the terrestrial snail, Helix pomatia, and the pond snail, Lymnaea stagnalis, were measured by using the HPLC technique. In both species an inhomogeneous distribution of OA was found in the central nervous system. The buccal ganglia contained a concentration of OA (12.6 pmol mg-1 and 18.8 pmol mg-1) that was two to three times higher than the pedal (4.93 pmol mg-1 and 9.2 pmol mg-1) or cerebral (4.46 pmol mg-1 and 4.9 pmol mg-1) ganglia of Helix and Lymnaea, respectively, whereas no detectable amount of OA could be assayed in the visceroparietal complex. In Lymnaea ganglia, the OA uptake into the synaptosomal fraction had a high (Km1 = 4.07 ± 0.51 μM, Vmax1 = 0.56 ± 0.11 pmol mg-1 per 20 min), and a low (Km2 = 47.6 ± 5.2 μM, Vmax2 = 4.2 ± 0.27 pmol mg-1 per 20 min), affinity component. A specific and dissociable 3H-OA binding to the membrane pellet prepared from the CNS of both Helix and Lymnaea was demonstrated. The Scatchard analysis of the ligand binding data showed a one-binding site, representing a single receptor site. The Kd and Bmax values were found to be 33.7 ± 5.95 nM and 1678 ± 179 fmol g-1 tissue in Helix and 84.9 ± 17.4 nM and 3803 ± 515 fmol g-1 tissue in Lymnaea preparation. The pharmacological properties of the putative molluscan OA receptor were characterized in both species and it was demonstrated that the receptor resembled the insect OA2 rather than to the cloned Lymnaea OA receptor. Immunocytochemical labelling demonstrated the presence of OA-immunoreactive neurons and fibres in the buccal, cerebral and pedal ganglia in the central nervous system of both species investigated. Electrophysiological experiments also suggested that the Lymnaea brain possessed specific receptors for OA. Local application of OA onto the identified buccal B2 neuron evoked a hyperpolarization which could selectively be inhibited by the OAergic agents phentolamine, demethylchlordimeform and 2-chloro-4-methyl-2

  11. Resurrection of Scolopendra longipes Wood and Scolopendra cubensis Saussure from synonymy with Scolopendra alternans Leach (Chilopoda, Scolopendromorpha, Scolopendridae): an enigmatic species-group needing phylogeographic analysis, with an overview on the origin and distribution of centipedes in the Caribbean region.

    PubMed

    Mercurio, Randy J

    2016-05-12

    Resurrection of Scolopendra longipes Wood, 1862, and Scolopendra cubensis Saussure, 1860, from junior synonymy with Scolopendra alternans Leach, 1815, is proposed. A neotype specimen of Scolopendra longipes is designated. Scolopendra longipes has a restricted range from the Dry Tortugas up through the Florida Keys of Monroe County into the mainland Florida counties of Collier and Dade southeast to the Bahamas, while Scolopendra cubensis is endemic to Cuba. Characters distinguishing S. longipes, and S. cubensis from S. alternans are illustrated and compared using digital photography, micrography and morphometric data. It is suggested that what has been considered Scolopendra alternans from southern Florida through the Caribbean and into northern South America is probably an evolving species-group that has undergone major diversification sometime during the Paleocene and early Eocene ~65.5-50 million years ago (Ma), mainly due to geographic isolation caused by a combination of plate tectonics and 100,000 year cycles of glaciation/deglaciation.

  12. Metabolic acceleration in the pond snail Lymnaea stagnalis?

    NASA Astrophysics Data System (ADS)

    Zimmer, Elke I.; Ducrot, V.; Jager, T.; Koene, J.; Lagadic, L.; Kooijman, S. A. L. M.

    2014-11-01

    Under constant environmental conditions, most animals tend to grow following the von Bertalanffy growth curve. Deviations from this curve can point to changes in the environment that the animals experience, such as food limitation when the available food is not sufficient or suitable. However, such deviations can also point to a phenomenon called metabolic acceleration, which is receiving increasing attention in the field of Dynamic Energy Budget (DEB) modeling. Reasons for such an acceleration are usually changes in shape during ontogeny, which cause changes in the surface area to volume ratio of the organism. Those changes, in turn, lead to changes in some of the model parameters that have length in their dimension. The life-history consequences of metabolic acceleration as implemented in the DEB theory are an s-shaped growth curve (when body size is expressed as a length measure) and a prolongation of the hatching time. The great pond snail Lymnaea stagnalis was earlier found to be food limited during the juvenile phase in laboratory experiments conducted under classical ecotoxicity test protocols. The pond snail has isomorphic shell growth but yet does not exhibit the expected von Bertalanffy growth curve under food limitation. When applying the standard DEB model to data from such life-cycle experiments, we also found that the hatching time is consistently underestimated, which could be a sign of metabolic acceleration. We here present an application of the DEB model including metabolic acceleration to the great pond snail. We account for the simultaneous hermaphroditism of the snail by including a model extension that describes the relative investment into the male and female function. This model allowed us to adequately predict the life history of the snail over the entire life cycle. However, the pond snail does not change in shape substantially after birth, so the original explanation for the metabolic acceleration does not hold. Since the change in shape

  13. Polyethylene mulch modifies greenhouse microclimate and reduces infection of phytophthora infestans in tomato and Pseudoperonospora cubensis in cucumber.

    PubMed

    Shtienberg, D; Elad, Y; Bornstein, M; Ziv, G; Grava, A; Cohen, S

    2010-01-01

    The individual and joint effects of covering the soil with polyethylene mulch before planting and fungicides commonly used by organic growers on tomato late blight (caused by Phytophthora infestans) were studied in three experiments conducted from 2002 to 2005. Application of fungicides resulted in inconsistent and insufficient late blight suppression (control efficacy +/- standard error of 34.5 +/- 14.3%) but the polyethylene mulch resulted in consistent, effective, and highly significant suppression (control efficacy of 83.6 +/- 5.5%) of the disease. The combined effect of the two measures was additive. In a second set of three experiments carried out between 2004 and 2006, it was found that the type of polyethylene mulch used (bicolor aluminized, clear, or black) did not affect the efficacy of late blight suppression (control efficacy of 60.1 to 95.8%) and the differences in the effects among the different polyethylene mulches used were insignificant. Next, the ability of the mulch to suppress cucumber downy mildew (caused by Pseudoperonospora cubensis) was studied in four experiments carried out between 2006 and 2008. The mulch effectively suppressed cucumber downy mildew but the effect was less substantial (control efficacy of 34.9 +/- 4.8%) than that achieved for tomato late blight. The disease-suppressing effect of mulch appeared to come from a reduction in leaf wetness duration, because mulching led to reductions in both the frequency of nights when dew formed and the number of dew hours per night when it formed. Mulching also reduced relative humidity in the canopy, which may have reduced sporulation.

  14. Behavioural responses of the snail Lymnaea acuminata to carbohydrates in snail-attractant pellets

    NASA Astrophysics Data System (ADS)

    Tiwari, Farindra; Singh, D. K.

    Snail control is one of the most important tools in the campaign to reduce the incidence of fascioliasis. In order to attain this objective, the method of bait formulation in order to contain an attractant and a molluscicide is an expedient approach to lure the target snail population to the molluscicide. This study identifies certain carbohydrates, namely sucrose, maltose, glucose, fructose and starch, for preparing such baits. These were tested on Lymnaea acuminata, an intermediate host of the digenean trematodes Fasciola hepatica and Fasciola gigantica. The behavioural responses of snails to these carbohydrates were examined. Significant variations in behavioural responses were observed in the snail even when the five carbohydrates were used in low concentrations in snail-attractant pellets. Starch emerged as the strongest attractant for Lymnaea acuminata, followed by maltose.

  15. The re-formation of connections in the nervous sytem of Lymnaea stagnalis after nerve injury.

    PubMed

    Janse, C; Kits, K S; Lever, A J

    1979-01-01

    Changes in the tentacle reflex pathway of the pond snail Lymnaea stagnalis induced by peripheral nerve injury were studied with behavioural and electrophysiological techniques. After nerve injury regeneration of sensory axons is obtained in 6-12 days, suggesting an axonal outgrowth at a rate of 1 mm per day. Recovery of the tentacle reflex takes much more time indicating that synaptic efficacy is affected considerably by the period of sensory deprivation following nerve injury.

  16. Prevalence of Fasciola in cattle and of its intermediate host Lymnaea snails in central Vietnam.

    PubMed

    Nguyen, Sam Thi; Nguyen, Duc Tan; Van Nguyen, Thoai; Huynh, Vu Vy; Le, Duc Quyet; Fukuda, Yasuhiro; Nakai, Yutaka

    2012-12-01

    The aims of this study were to investigate the prevalence of natural Fasciola infections in both the definitive hosts (cattle) and the intermediate hosts (Lymnaea snails) in central Vietnam. A total of 1,075 fecal samples, randomly collected from cattle in Binh Dinh, Khanh Hoa, and Phu Yen provinces, were examined for Fasciola eggs by a sedimentation method. The overall prevalence of Fasciola was 45.3 %. A subset of the animals (235) was also screened for antibodies against Fasciola by an enzyme-linked immunosorbent assay. Overall, 46.3 % of these animals were shedding Fasciola eggs while 87.2 % were Fasciola seropositive. A lower prevalence of Fasciola was observed in calves ≤ 2 years of age (37.6 %) compared to that in cattle >2 years of age (53.7 %) (p < 0.05). The prevalence in the rainy season (50.8 %) was significantly different to that in the dry season (38.1 %) (p < 0.05). Of the 3.269 Lymnaea viridis and 1.128 Lymnaea swinhoei examined, 31 (0.95 %) and seven (0.62 %), respectively, were found to be infected with Fasciola. This appears to be the first epidemiological survey of the prevalence of Fasciola in cattle and snails in these three provinces in central Vietnam.

  17. Effects of Developmental Temperature on Gametocysts and Oocysts of Two Species of Gregarines Blabericola migrator and Blabericola cubensis (Apicomplexa: Eugregarinida: Blabericolidae) Parasitizing Blaberid Cockroaches (Dictyoptera: Blaberidae).

    PubMed

    Kolman, Jon A; Clopton, Richard E; Clopton, Debra T

    2015-12-01

    Abiotic environmental conditions, especially temperature and humidity, have profound effects on the growth and development of gregarines, but these effects remain largely undocumented. Quantifying the effects of environmental conditions on the growth and development of exogenous gregarine ontogenetic stages is an important first step in understanding the transmission, population dynamics, and environmental persistence of gregarine infection. In this study, we examined the effect of 6 environmental temperatures (10, 18, 22, 27, 35, and 40 C) at constant humidity (0 mmHg vapor pressure deficit) on gametocyst development and oocyst viability in 2 gregarine species: Blabericola migrator and Blabericola cubensis parasitizing the Tiger-striped Hissing Cockroach, Princisia vanwaerebecki, and the Discoid Cockroach, Blaberus discoidalis, respectively. Temperature has a significant effect on gametocyst development and oocyst viability for both gregarine species. Gametocyst development for both gregarine species displays a similar threshold response to environmental temperature: 10 and 40 C represent extremes outside their developmental range, but within these extremes, the relationship between gametocyst development and temperature is weakly direct. Dehiscence increased with temperature from 68% at 18 C to 93% at 22 C and remained at that level through 35 C. Developmental temperature also has a meaningful but inverse effect on oocyst viability of both B. migrator and B. cubensis. For both species, oocyst viability is highest at 18 and 22 C and is significantly reduced at 27 and 35 C. Thus oocyst production and sporozoite viability are linked but environmentally independent phenomena. Overall, there is an acceptable developmental temperature zone for B. migrator and B. cubensis that ranges from 18 to 27 C, but production of viable sporozoites is greatest in a relatively narrow zone around 22 C. Prior studies have postulated that mechanisms that concentrate oocysts and hosts

  18. Enzyme Inhibition by Molluscicidal Components of Myristica fragrans Houtt. in the Nervous Tissue of Snail Lymnaea acuminata

    PubMed Central

    Jaiswal, Preetee; Kumar, Pradeep; Singh, V. K.; Singh, D. K.

    2010-01-01

    This study was designed to investigate the effects of molluscicidal components of Myristica fragrans Houtt. (Myristicaceae) on certain enzymes in the nervous tissue of freshwater snail Lymnaea acuminata Lamarck (Lymnaeidae). In vivo and in vitro treatments of trimyristin and myristicin (active molluscicidal components of Myristica fragrans Houtt.) significantly inhibited the acetylcholinesterase (AChE), acid and alkaline phosphatase (ACP/ALP) activities in the nervous tissue of Lymnaea acuminata. The inhibition kinetics of these enzymes indicates that both the trimyristin and myristicin caused competitive noncompetitive inhibition of AChE. Trimyristin caused uncompetitive and competitive/noncompetitive inhibitions of ACP and ALP, respectively whereas the myristicin caused competitive and uncompetitive inhibition of ACP and ALP, respectively. Thus results from the present study suggest that inhibition of AChE, ACP, and ALP by trimyristin and myristicin in the snail Lymnaea acuminata may be the cause of the molluscicidal activity of Myristica fragrans. PMID:21048864

  19. Enzyme Inhibition by Molluscicidal Components of Myristica fragrans Houtt. in the Nervous Tissue of Snail Lymnaea acuminata.

    PubMed

    Jaiswal, Preetee; Kumar, Pradeep; Singh, V K; Singh, D K

    2010-01-01

    This study was designed to investigate the effects of molluscicidal components of Myristica fragrans Houtt. (Myristicaceae) on certain enzymes in the nervous tissue of freshwater snail Lymnaea acuminata Lamarck (Lymnaeidae). In vivo and in vitro treatments of trimyristin and myristicin (active molluscicidal components of Myristica fragrans Houtt.) significantly inhibited the acetylcholinesterase (AChE), acid and alkaline phosphatase (ACP/ALP) activities in the nervous tissue of Lymnaea acuminata. The inhibition kinetics of these enzymes indicates that both the trimyristin and myristicin caused competitive noncompetitive inhibition of AChE. Trimyristin caused uncompetitive and competitive/noncompetitive inhibitions of ACP and ALP, respectively whereas the myristicin caused competitive and uncompetitive inhibition of ACP and ALP, respectively. Thus results from the present study suggest that inhibition of AChE, ACP, and ALP by trimyristin and myristicin in the snail Lymnaea acuminata may be the cause of the molluscicidal activity of Myristica fragrans.

  20. Origin of automaticity and neural regulation of peristalsis in the gastrointestinal tract of Aplysia and Lymnaea. Short communication.

    PubMed

    Kurokawa, M; Kasuya, Y; Okamoto, T

    2012-01-01

    We examined whether the enteric nervous system (ENS) is capable of controlling autonomous peristalsis, which occurs in the crop of Aplysia as well as in the esophagus of Lymnaea. Interestingly, "pacemaker neurons", which lead peristaltic rhythm, were found in the gizzard in Aplysia and in the crop in Lymnaea; both of these structures are located distal to the regions exhibiting peristalsis. Thus, the bursting activity of the ENS first occurred in lower regions and then progressed in an ascending direction (i.e. in the opposite direction of peristalsis). The two species are thought to differ in terms of the mechanisms involved in producing peristalsis.

  1. IMA Genome-F 5: Draft genome sequences of Ceratocystis eucalypticola, Chrysoporthe cubensis, C. deuterocubensis, Davidsoniella virescens, Fusarium temperatum,Graphilbum fragrans, Penicillium nordicum, and Thielaviopsis musarum.

    PubMed

    Wingfield, Brenda D; Barnes, Irene; Wilhelm de Beer, Z; De Vos, Lieschen; Duong, Tuan A; Kanzi, Aquillah M; Naidoo, Kershney; Nguyen, Hai D T; Santana, Quentin C; Sayari, Mohammad; Seifert, Keith A; Steenkamp, Emma T; Trollip, Conrad; van der Merwe, Nicolaas A; van der Nest, Magriet A; Markus Wilken, P; Wingfield, Michael J

    2015-12-01

    The genomes of Ceratocystis eucalypticola, Chrysoporthe cubensis, Chrysoporthe deuterocubensis, Davidsoniella virescens, Fusarium temperatum, Graphilbum fragrans, Penicillium nordicum and Thielaviopsis musarum are presented in this genome announcement. These seven genomes are from plant pathogens and otherwise economically important fungal species. The genome sizes range from 28 Mb in the case of T. musarum to 45 Mb for Fusarium temperatum. These genomes include the first reports of genomes for the genera Davidsoniella, Graphilbum and Thielaviopsis. The availability of these genome data will provide opportunities to resolve longstanding questions regarding the taxonomy of species in these genera. In addition these genome sequences through comparative studies with closely related organisms will increase our understanding of how these pathogens cause disease.

  2. Toxicological effect and biochemical alterations induced by different fractions of Euphorbia royleana latex in freshwater harmful vector snail Lymnaea acuminata.

    PubMed

    Tiwari, Sudhanshu; Singh, S K; Singh, Ajay

    2004-12-01

    Laboratory evaluation was made to assess the molluscicidal activity of different fractions of Euphorbia royleana (Family- Euphorbiaceae) latex obtained through sephadex gel column against freshwater snail Lymnaea (Radix) acuminata Lamarack. This snail is the vector of liver fluke, Fasciola hepatica Linnaeus and Fasciola gigantica Cobbold, which causes endemic fascioliasis in cattle and livestock. The toxic effect of the different fractions was time dependent and fifth fraction obtained through benzene: ethyl acetate (5:5) had maximum molluscicidal activity against Lymnaea acuminata. There was a significant negative correlation between LC values and exposure periods thus increase in exposure time, the LC50 value of V fraction of Euphorbia royleana latex was decreased from 14.28 mg/l (24 hr) to 9.28 mg/l (96 hr) against Lymnaea acuminata. After exposure to sub-lethal concentrations of this fraction there were significant time and dose dependent alterations observed in pyruvate, lactate levels, ALAT, AAT, AChE and cytochrome oxidase enzyme activities in different body tissues of Lymnaea acuminata. It is proposed that the fifth fraction of E. royleana latex can be used as a molluscicide for controlling the harmful snail population from aquatic ecosystem without any harm due to their reversible toxic action.

  3. Activities and functions of peripheral neurons in the enteric nervous system of Aplysia and Lymnaea.

    PubMed

    Kurokawa, M; Ito, S; Okamoto, T

    2008-01-01

    In order to explore the functions of the peripheral neurons in the enteric nervous system (ENS) of the gastropods, Aplysia and Lymnaea, we investigated the correlation between peripheral neuronal activities and movements of the digestive tract. In Aplysia, movements of the gizzard were distinguished into two types of contraction: a large constriction of the whole gizzard following bursting activities of the neurons on the gizzard and EJP-like potentials in the musculature; and a small contraction of a restricted part of the gizzard following a slow muscle potential. When TTX was applied to isolated gizzard preparation, the bursting activities were blocked and the EJP-like potentials and the subsequent constriction disappeared, whereas the slow potentials in the musculature and partial contractions appeared to be unaffected. Therefore, it was suggested that the peripheral neurons on the gizzard were motor neurons for constriction, while the partial contraction was thought to be myogenic. In Lymnaea, we recorded periodic bursting activities in the enteric nervous system that were followed by EJP-like potentials and gastrointestinal movements. The results show that, in both species, there may exist motor neurons in the ENS that are responsible for neurogenic movements of the digestive tract.

  4. Attraction to amino acids by Lymnaea acuminata, the snail host of Fasciola species.

    PubMed

    Tiwari, F; Singh, D K

    2004-04-01

    Adult Lymnaea acuminata (average length 20-22 mm) were collected locally from lakes and low-lying submerged fields from Gorakhpur. The chemoattraction studies were made in round glass aquaria measuring 30 cm in diameter and filled to a depth of 10 mm with 500 ml dechlorinated tap water. Each aquarium was divided into four concentric zones. At the starting time of the assay 10 snails were placed on the circumference of outermost zone 0. Snail attractant pellets (SAP) were added simultaneously in the center of central zone 3. SAP of different amino acids were prepared at concentrations of 10, 20, 50, 80 and 100 mM/2% agar solution and, subsequently, spread to a uniform thickness of 5 mm. After cooling, SAP were cut in small pieces of 5 mm in diameter. Lymnaea acuminata's attraction to amino acids was studied using different amino acid concentrations in SAP. Pellets containing amino acids with non-polar R groups (proline and tryptophan), a charged polar group (arginine) and uncharged polar R groups (serine, citrulline and asparagine) were tested. The snails were more attracted to the uncharged polar R group amino acid serine than to other groups of amino acids. The preferred amino acid concentration was 80 mM. The attraction of snails to different amino acids was concentration dependent. Snails could discriminate amongst the different amino acids at > or = 50 mM.

  5. Assessment of the FasciMol-ELISA in the detection of the trematode Fasciola hepatica in field-collected Galba cubensis: a novel tool for the malacological survey of fasciolosis transmission.

    PubMed

    Alba, Annia; Vázquez, Antonio A; Sánchez, Jorge; Fraga, Jorge; Hernández, Hilda; Martínez, Elizabeth; Marcet, Ricardo; Figueredo, Mabel; Sarracent, Jorge

    2016-01-16

    Fasciolosis is one of the food-borne neglected trematodioses that has reemerged as a human disease while its effects on domestic animal health remains of significant economic consideration. Being snail-borne disease, the accurate and time-saving epidemiological surveillance of the transmission foci where infected lymnaeid snails occur could be essential to effectively focus or redirect control strategies. For this purpose, the first monoclonal antibody-based immunoenzymatic assay to detect Fasciola hepatica-infected snails (FasciMol-ELISA) was recently developed and showed a high sensitivity and specificity when tested in an experimental F. hepatica - Galba cubensis system. Here, we surveyed populations of G. cubensis occurring in western Cuba for the assessment of the FasciMol-ELISA in determining natural F. hepatica infection in this intermediate host. A multiplex PCR, previously developed to detect F. hepatica in G. cubensis, was used for sample classification. Snail dissection method was also employed as screening technique. A Χ(2) test and a Kappa index were calculated to evaluate the positivity and the level of agreement between the FasciMol-ELISA and the snail dissection methods with the multiplex PCR, respectively. Galba cubensis was found in nine out of 12 sampled localities of which four were positive for F. hepatica infection as detected by both immunoenzymatic and PCR-based assays. The overall prevalence was higher than the natural infection rates previously reported for Cuban G. cubensis (range from 4.1 to 7.42% depending on the screening method). No significant differences were found between FasciMol-ELISA and multiplex PCR when determining parasite positivity (Χ(2) = 6.283; P = 0.0981) whereas an excellent agreement was also noted (Kappa = 0.8224). Our results demonstrate the importance of malacological surveys in assessing parasite transmission risk and constitute an alert on the need of accurate measures to control fasciolosis in

  6. Methamphetamine enhances memory of operantly conditioned respiratory behavior in the snail Lymnaea stagnalis.

    PubMed

    Kennedy, Colin D; Houmes, Stephen W; Wyrick, Katherine L; Kammerzell, Samuel M; Lukowiak, Ken; Sorg, Barbara A

    2010-06-15

    Amphetamines have been used as cognitive enhancers to promote learning and memory. Amphetamines are also drugs of abuse that may promote the initiation of strong memories that ultimately lead to addiction. To understand how methamphetamine (Meth) may be augmenting learning and memory, we chose a relatively simple system, the pond snail, Lymnaea stagnalis. We studied the effects of Meth exposure on the long-term memory (LTM), extinction and reinstatement of operantly conditioned aerial respiratory behavior in Lymnaea. We first determined doses of Meth that would acutely alter respiratory behavior. Next, we measured the impact of training snails in Meth solution or water (control group) using a training procedure that produces LTM (>6 h) in control conditions. Meth exposure impaired the expression of LTM 21 h after two training sessions, but this appeared to be a context-dependent effect only. However, snails exposed to 3.3 mumol l(-1) Meth during training had a decreased rate of extinction of the operantly conditioned memory. We then tested whether this decreased ability of snails to extinguish memory was due to enhanced LTM or impaired extinction of that memory. Snails were operantly conditioned in water and exposed to Meth 16 h after their last trial but 4-5 h prior to extinction. Meth produced an increase rather than a decrease in extinction rate. Thus, Meth impaired extinction only when snails were exposed to Meth during training. Last, we tested the effect of Meth on the ability to form LTM using a single training procedure that is suboptimal for LTM formation. Control snails did not demonstrate LTM, as expected, but pre-exposure of snails to 3.3 micromol l(-1) Meth 24 h prior to the single training session produced LTM 24 h later, indicating that Meth pre-exposure primed snails for LTM formation. Taken together, our studies suggest that LTM is strengthened by Meth such that extinction training is less effective. Lymnaea provides a simple and useful model

  7. The participation of NMDA receptors, PKC, and MAPK in Lymnaea memory extinction.

    PubMed

    Rosenegger, David; Lukowiak, Ken

    2013-02-01

    The aerial respiratory behavior of Lymnaea can be operantly conditioned to form a long-term memory (LTM) that will persist for >24h. LTM formation is dependent on altered gene activity and new protein synthesis, with the N-methyl-D-aspartate (NMDA) receptors, mitogen activated protein kinase (MAPK), and protein kinase C (PKC) pathways playing a critical role. LTM can also undergo extinction, whereby the original memory is temporarily masked by a new memory. Here we investigate if the formation of an extinction memory uses similar molecular pathways to those required for LTM formation. We find that the formation of the extinction memory can be blocked by inhibitors of NMDA receptors, PKC, and MAPK suggesting that extinction memory formation uses similar mechanisms to that of 'normal' memory formation.

  8. Growth, fecundity and glycogen utilization in Lymnaea palustris exposed to atrazine and hexachlorobenzene in freshwater mesocosms

    SciTech Connect

    Baturo, W.; Lagadic, L.; Caquet, T.

    1995-03-01

    Freshwater mesocosms were used to study the long-term sublethal effects of atrazine and hexachlorobenzene (HCB) on a basommatophoran gastropod, Lymnaea palustris (Mueller). Growth, fecundity, and biochemical parameters related to polysaccharide metabolism of pesticide-exposed snails were compared with those of control animals maintained in untreated mesocosms. HCB inhibited body growth and stimulated egg production, whereas atrazine had no relevant effect on these physiological parameters. Also, HCB stimulated the activity of polysaccharide-hydrolyzing enzymes, suggesting that changes in the metabolism of reserve polysaccharides (glycogen) may be involved in the inhibition of growth and increase of fecundity. In contrast, atrazine had no effect on the metabolism of polysaccharides. It is concluded that the effects of HCB are related to its neurotoxicity that would have affected the neurohormonal control of growth and reproduction of exposed snails. It is suggested that polysaccharide-hydrolyzing enzymes may be used as biomarkers to predict the effects of neurotoxic pesticides on freshwater snail populations.

  9. [The growth and energy metabolism of Lymnaea stagnalis (Lymnaeidae, Gastropoda): I. Early postlarval period].

    PubMed

    Zotin, A A

    2009-01-01

    The growth and the oxygen uptake rate of Lymnaea stagnalis were studied during the first ten days after hatching. It is shown that these processes are atypical during early ontogenesis in comparison with adult mollusks. The obtained data on linear (height of shell) and weight growth can be equally well approximated with the von Bertalanffy equation or exponential and polynomial equations. Both linear and weight growth are characterized by an approximately constant specific rate associated with synchronous oscillations of a two-week period. The oscillations were observed also for the oxygen uptake rate, but of another period (about 2.6 weeks). On average the metabolic rate after the initial triple increase during the first three days remains stable. The polynomial coefficient of the allometric dependence of the total weight on the shell height is less reliable than that of the adult.

  10. Evidence for genetic influences on neurotransmitter content of identified neurones of Lymnaea stagnalis.

    PubMed

    Audesirk, G; Audesirk, T; McCaman, R E; Ono, J K

    1985-01-01

    Neurotransmitter content was measured in two identified giant neurones in isogenic and wild-type populations of the freshwater pond snail Lymnaea stagnalis. The paired serotonergic cerebral giant neurones (LC1 and RC1) have higher transmitter levels and less variability in inbred animals than in wild-type animals. The transmitter content of the unpaired dopaminergic right pedal giant neurone (RPeD1) does not differ between inbred and wild-type animals in either level or variability. It is proposed that serotonin content of the cerebral giant neurones is under partial genetic control, and that animals of the wild-type population may possess a number of different alleles for the genes influencing serotonin levels. Inbreeding resulted in fixation of an allele promoting high serotonin levels. This particular wild-type population is probably already isogenic for genes influencing dopamine content in the right pedal giant neurone.

  11. Amine-containing neurons in the brain of Lymnaea stagnalis: distribution and effects of precursors.

    PubMed

    Audesirk, G

    1985-01-01

    Glyoxylic acid-induced fluorescence in whole-brain preparations of the central nervous system of the freshwater pond snail, Lymnaea stagnalis, was used to map the distribution of serotonin-and dopamine-containing neurons. Serotonin and dopamine were easily distinguishable by differences in color of fluorescence. Serotonin-containing neurons were consistently found in the cerebral, pedal, right parietal and visceral ganglia. Dopamine-containing neurons were found in the pedal, and buccal ganglia. Prior incubation of brains in 5-hydroxytryptophan (5-HTP), the immediate precursor to serotonin, produced serotonin-like fluoresence in neurons which do not normally fluoresce. These neurons thus probably possess specific uptake mechanisms for 5-HTP. Since 5-HTP itself fluoresces yellow, the glyoxylic acid technique cannot determine if these neurons contain the enzyme aromatic amino acid decarboxylase, which converts 5-HTP to serotonin, or merely fluoresce because of the 5-HTP taken into the cells.

  12. Sequential exposure to a combination of stressors blocks memory reconsolidation in Lymnaea.

    PubMed

    Dodd, Shawn Xavier; Lukowiak, Ken

    2015-03-01

    Stress alters the formation of long-term memory (LTM) in Lymnaea. When snails are exposed to more than one stressor, however, how the memory is altered becomes complicated. Here, we investigated how multiple stressors applied in a specific pattern affect an aspect of memory not often studied in regards to stress - reconsolidation. We hypothesized that the application of a sequence of stressors would block the reconsolidation process. Reconsolidation occurs following activation of a previously formed memory. Sequential crowding and handling were used as the stressors to block reconsolidation. When the two stressors were sequentially presented immediately following memory activation, reconsolidation was blocked. However, if the sequential presentation of the stressors was delayed for 1 h after memory activation, reconsolidation was not blocked. That is, LTM was observed. Finally, presentation of either stressor alone did not block reconsolidation. Thus, stressors can block reconsolidation, which may be preferable to pharmacological manipulations. © 2015. Published by The Company of Biologists Ltd.

  13. Sub-lethal cadmium exposure increases phytochelatin concentrations in the aquatic snail Lymnaea stagnalis.

    PubMed

    Sf, Gonçalves; Sk, Davies; Bennett, M; Raab, A; Feldmann, J; Kille, P; Loureiro, S; Dj, Spurgeon; Jg, Bundy

    2016-10-15

    Phytochelatins are metal-binding metabolites found in almost all plant species and some animal groups, including nematodes and annelids, where they can play an important role in detoxifying metals such as cadmium. Species from several other taxa contain a phytochelatin synthase (PCS) gene orthologue, including molluscs, indicating they may have the potential to synthesize phytochelatins. However, the presence of a gene alone does not demonstrate that it plays a functional role in metal detoxification. In the present study, we show that the aquatic snail Lymnaea stagnalis produced both penta- and heptapeptide phytochelatins (i.e. phytochelatin-2 and phytochelatin-3), and their levels increased in response to sub-lethal levels of cadmium. Copyright © 2016. Published by Elsevier B.V.

  14. Juveniles of Lymnaea 'smart' snails do not perseverate and have the capacity to form LTM.

    PubMed

    Shymansky, Tamila; Protheroe, Amy; Hughes, Emily; Swinton, Cayley; Swinton, Erin; Lukowiak, Kai S; Phillips, Iain; Lukowiak, Ken

    2017-02-01

    Previously, it was concluded that the nervous systems of juvenile snails were not capable of mediating long-term memory (LTM). However, exposure and training of those juvenile snails in the presence of a predator cue significantly altered their ability to learn and form LTM. In addition, there are some strains of Lymnaea which have been identified as 'smart'. These snails form LTM significantly better than the lab-bred strain. Here, we show that juveniles of two smart snail strains not only are capable of associative learning but also have the capacity to form LTM following a single 0.5 h training session. We also show that freshly collected 'wild' 'average' juveniles are also not able to form LTM. Thus, the smart snail phenotype in these strains is expressed in juveniles.

  15. Influence of shell size of Lymnaea columella on infectivity and development of Fasciola hepatica.

    PubMed

    Coelho, L H L; Guimarães, M P; Lima, W S

    2008-03-01

    Experimental infections of Lymnaea columella with Fasciola hepatica were carried out to determine the influence of shell size on the infection rate and on the outcome of rediae and cercariae. Snails were divided into seven groups according to shell size: 2-4 mm, 5-6 mm, 7-8 mm, 9-10 mm, 11-12 mm, 13-14 mm and 15 mm or more. One hundred snails in each group were infected by using four miracidia for each snail. Snails with larger shell size showed a lower infection rate, the groups presenting the highest (79%) and lowest (2%) proportions of positives being those of 5-6 mm and 15 mm or more, respectively. Cercariae were present in 21% of them at 31 days post-infection, and cercarial shedding was observed 61 days post-infection. It was concluded that there is a non-linear negative association between shell size and infection rate.

  16. The presence of predators modifies the larval development of Fasciola hepatica in surviving Lymnaea truncatula.

    PubMed

    Rondelaud, D; Vignoles, P; Dreyfuss, G

    2002-06-01

    Experimental infections of Lymnaea truncatula with Fasciola hepatica were performed to study the consequences of the presence of predators (sciomyzid larvae or zonitid snails) on the characteristics of larval F. hepatica development in surviving snails. Controls consisted of infected snails that were not subjected to predators. Compared to controls, the survival rate at day 30 post-exposure, the duration of cercarial shedding, and the number of cercariae shed by surviving snails were significantly lower when predators were present in snail breeding boxes, whatever the type of predator used. In contrast, the prevalences of Fasciola infections in snails, and the length of time between exposure and the onset of cercarial shedding showed no significant variation. The progressive development of a stress reaction in surviving snails against predators during the first 30 days of experimental exposure to F. hepatica would influence snail survival during the cercarial shedding period and, consequently, the number of cercariae shed by the snails.

  17. Seasonal transmission of Fasciola hepatica in cattle and Lymnaea (Fossaria) humilis snails in central Mexico.

    PubMed

    Cruz-Mendoza, I; Ibarra-Velarde, F; Quintero-Martínez, M T; Naranjo-García, E; Lecumberri-López, J; Correa, D

    2005-03-01

    A 19-month study on the prevalence of fasciolosis in 30 naturally infected cows, the presence of infected and non-infected Lymnaea (Fossaria) humilis snails, and variation in soil temperature and humidity is reported. The prevalence of fasciolosis in cattle declined from around 50% in March to 30% in July, then, it increased from August, reaching a plateau of 100% in November-January, before gradually declining thereafter. A rise in soil humidity and temperature in June and July, respectively, which peaked between August and November was observed. In July, L. (F.) humilis snails appeared, but the infection could only be found in these in August and November. The number of infected snails did not reflect the infestation rate in cows, even though the infestation kinetics in both hosts behaved as predicted from the life cycle of the parasite.

  18. Fasciola gigantica: the growth and larval productivity of redial generations in the snail Lymnaea truncatula.

    PubMed

    Dar, Y; Vignoles, P; Rondelaud, D; Dreyfuss, G

    2002-04-01

    Bimiracidial infections of French Lymnaea truncatula with a Madagascan isolate of Fasciola gigantica were carried out under laboratory conditions to study the growth of rediae and their larval productivity in relation to the different redial generations. The total numbers of rediae and their mean lengths significantly increased with the duration of infection until day 49 post-exposure (p.e.). Significant differences in the lengths between the different redial generations were noted. At day 49 p.e. (at 20 degrees C), the cercariae were produced by the first redial generation, while the productivity of other redial groups was delayed. This last finding shows a slow larval development of this Madagascan isolate of F. gigantica in this French population of L. truncatula.

  19. Detection of Lymnaea columella infection by Fasciola hepatica through Multiplex-PCR.

    PubMed

    Magalhães, Kelly Grace; Passos, Liana Konovaloff Jannotti; Carvalho, Omar dos Santos

    2004-06-01

    From complete mitochondrial DNA sequence of Fasciola hepatica available in Genbank, specific primers were designed for a conserved and repetitive region of this trematode. A pair of primers was used for diagnosis of infected Lymnaea columella by F. hepatica during the pre-patent period simultaneously with another pair of primers which amplified the internal transcribed spacer (ITS) region of rDNA from L. columella in a single Multiplex-PCR. The amplification generated a ladder band profile specific for F. hepatica. This profile was observed in positive molluscs at different times of infection, including adult worms from the trematode. The Multiplex-PCR technique showed to be a fast and safe tool for fascioliasis diagnosis, enabling the detection of F. hepatica miracidia in L. columella during the pre-patent period and identification of transmission areas.

  20. Behavioural responses of the snail Lymnaea acuminata to carbohydrates and amino acids in bait pellets.

    PubMed

    Agrahari, P; Singh, D K

    2010-12-01

    Snail control could play an important role in programmes against fascioliasis, especially if the methods used for molluscicide delivery could be improved, such as by the development of bait formulations containing both an effective attractant and a molluscicide, to ensure good levels of contact between the molluscicide and the target snail populations. In a recent study, the attractiveness to Lymnaea acuminata (an intermediate host of the digenean trematode Fasciola gigantica) of potential components of snail-attractant pellets was investigated. Carbohydrates (glucose, maltose, sucrose or starch, each at 10 mM) and amino acids (citrulline, tryptophan, proline or serine, each at 20 mM), were tested in aquaria, with the snails initially placed 22.5, 30 or 45 cm from an agar pellet containing the component under test. Under these conditions, starch and proline emerged as the strongest attractants for L. acuminata, followed by maltose and serine.

  1. A cholinergic modulatory interneuron in the feeding system of the snail, Lymnaea.

    PubMed

    Yeoman, M S; Parish, D C; Benjamin, P R

    1993-07-01

    1. Pharmacological and physiological methods were used to examine the role of acetylcholine (ACh) in modulation of the Lymnaea feeding central pattern generator (CPG) by the slow oscillator (SO) interneuron. 2. Extracts of dissected SO cell bodies inhibited spontaneous ventricular contractions of the clam Mya arenaria, indicating the presence of ACh. These effects were blocked by the specific antagonist benzoquinonium chloride (10(-7) M). 3. Isolated SO cells grown in culture synthesized ACh from tritiated choline. 4. High [K+] saline induced release of synthesized ACh from cultured SO cells into the medium. 5. The specific ACh antagonist phenyltrimethylammonium (10(-4) M) blocked both excitatory, biphasic (inhibitory-excitatory) and inhibitory monosynaptic connections from the SO to feeding CPG interneurons and motor neurons. Less specific cholinergic antagonists blocked either excitatory (hexamethonium, 10(-4) M) or both excitatory and inhibitory connections (d-tubo-curarine, 10(-4) M). 6. The synaptic responses of the SO could be mimicked by brief (20 ms) pressure-pulsed application of ACh onto the cell bodies of the postsynaptic cells in high-Mg2+ saline. In normal saline, ACh elicited bursts of spikes in the N1 cells, indicating that a fictive feeding pattern had been induced in the CPG. This mimics the main mechanism by which the SO activates the CPG, which is by exciting the N1s. 7. The frequency of SO-induced fictive feeding rhythm was reduced by bath application of hexamethonium chloride to the buccal ganglia. This reduced the amplitude of the SO-->N1 excitatory synaptic response (30% of controls) and is probably the main mechanism for the reduction in the frequency of the rhythm. 8. The evidence suggests that ACh is the main neurochemical involved in allowing the SO to initiate and control the frequency of the Lymnaea feeding CPG.

  2. Neuronal somata and extrasomal compartments play distinct roles during synapse formation between Lymnaea neurons.

    PubMed

    Xu, Fenglian; Luk, Collin C; Wiersma-Meems, Ryanne; Baehre, Kelly; Herman, Cameron; Zaidi, Wali; Wong, Noelle; Syed, Naweed I

    2014-08-20

    Proper synapse formation is pivotal for all nervous system functions. However, the precise mechanisms remain elusive. Moreover, compared with the neuromuscular junction, steps regulating the synaptogenic program at central cholinergic synapses remain poorly defined. In this study, we identified different roles of neuronal compartments (somal vs extrasomal) in chemical and electrical synaptogenesis. Specifically, the electrically synapsed Lymnaea pedal dorsal A cluster neurons were used to study electrical synapses, whereas chemical synaptic partners, visceral dorsal 4 (presynaptic, cholinergic), and left pedal dorsal 1 (LPeD1; postsynaptic) were explored for chemical synapse formation. Neurons were cultured in a soma-soma or soma-axon configuration and synapses explored electrophysiologically. We provide the first direct evidence that electrical synapses develop in a soma-soma, but not soma-axon (removal of soma) configuration, indicating the requirement of gene transcription regulation in the somata of both synaptic partners. In addition, the soma-soma electrical coupling was contingent upon trophic factors present in Lymnaea brain-conditioned medium. Further, we demonstrate that chemical (cholinergic) synapses between soma-soma and soma-axon pairs were indistinguishable, with both exhibiting a high degree of contact site and target cell type specificity. We also provide direct evidence that presynaptic cell contact-mediated, clustering of postsynaptic cholinergic receptors at the synaptic site requires transmitter-receptor interaction, receptor internalization, and a protein kinase C-dependent lateral migration toward the contact site. This study provides novel insights into synaptogenesis between central neurons revealing both distinct and synergistic roles of cell-cell signaling and extrinsic trophic factors in executing the synaptogenic program. Copyright © 2014 the authors 0270-6474/14/3411304-12$15.00/0.

  3. Electrophysiological characteristics of feeding-related neurons after taste avoidance Pavlovian conditioning in Lymnaea stagnalis.

    PubMed

    Sunada, Hiroshi; Takigami, Satoshi; Lukowiak, Ken; Sakakibara, Manabu

    2014-01-01

    Taste avoidance conditioning (TAC) was carried out on the pond snail, Lymnaea stagnalis. The conditional stimulus (CS) was sucrose which elicits feeding behavior; while the unconditional stimulus (US) was a tactile stimulus to the head which causes feeding to be suppressed. The neuronal circuit that drives feeding behavior in Lymnaea is well worked out. We therefore compared the physiological characteristics on 3 classes of neurons involved with feeding behavior especially in response to the CS in conditioned vs. control snails. The cerebral giant cell (CGC) modulates feeding behavior, N1 medial neuron (N1M) is one of the central pattern generator neurons that organizes feeding behavior, while B3 is a motor neuron active during the rasp phase of feeding. We found the resting membrane potential in CGC was hyperpolarized significantly in conditioned snails but impulse activity remained the same between conditioned vs. control snails. There was, however, a significant increase in spontaneous activity and a significant depolarization of N1M's resting membrane potential in conditioned snails. These changes in N1M activity as a result of training are thought to be due to withdrawal interneuron RPeD11 altering the activity of the CGCs. Finally, in B3 there was: 1) a significant decrease in the amplitude and the frequency of the post-synaptic potentials; 2) a significant hyperpolarization of resting membrane potential in conditioned snails; and 3) a disappearance of bursting activity typically initiated by the CS. These neuronal modifications are consistent with the behavioral phenotype elicited by the CS following conditioning.

  4. Embryonic exposure to model naphthenic acids delays growth and hatching in the pond snail Lymnaea stagnalis.

    PubMed

    Johnston, Christina U; Clothier, Lindsay N; Quesnel, Dean M; Gieg, Lisa M; Chua, Gordon; Hermann, Petra M; Wildering, Willem C

    2017-02-01

    Naphthenic acids (NAs), a class of structurally diverse carboxylic acids with often complex ring structures and large aliphatic tail groups, are important by-products of many petrochemical processes including the oil sands mining activity of Northern Alberta. While it is evident that NAs have both acute and chronic harmful effects on many organisms, many aspects of their toxicity remain to be clarified. Particularly, while substantive data sets have been collected on NA toxicity in aquatic prokaryote and vertebrate model systems, to date, nothing is known about the toxic effects of these compounds on the embryonic development of aquatic invertebrate taxa, including freshwater mollusks. This study examines under laboratory conditions the toxicity of NAs extracted from oil sands process water (OSPW) and the low-molecular weight model NAs cyclohexylsuccinic acid (CHSA), cyclohexanebutyric acid (CHBA), and 4-tert-butylcyclohexane carboxylic acid (4-TBCA) on embryonic development of the snail Lymnaea stagnalis, a common freshwater gastropod with a broad Palearctic distribution. Evidence is provided for concentration-dependent teratogenic effects of both OSPW-derived and model NAs with remarkably similar nominal threshold concentrations between 15 and 20 mg/L and 28d EC50 of 31 mg/L. In addition, the data provide evidence for substantial toxicokinetic differences between CHSA, CHBA and 4-TBCA. Together, our study introduces Lymnaea stagnalis embryonic development as an effective model to assay NA-toxicity and identifies molecular architecture as a potentially important toxicokinetic parameter in the toxicity of low-molecular weight NA in embryonic development of aquatic gastropods.

  5. Morphological and ecological studies on Lymnaea natalensis the snail vector of Fasciola gigantica in Egypt.

    PubMed

    el-Dafrawy, Shadia M

    2002-08-01

    Lymnaea natalensis were collected from several localities in Giza Governorate (El-Mansouria, Kafr Hakim and The Nile). The collected snails were examined for cercarial shedding and measurement of shell was carried out using a virner caliper. A total of 217 Lymnaea was collected from all habitats and 24 snails were found to shed Fasciola gigantica cercariae with infection rate 11.1%. The ratio of shell height to shell width (H/W) ranged 1.7-2.1. The ratio between length of aperture to shell height (A/H) was almost constant ranged 0.7-0.8. While the ratio between length of aperture and shell width (A/W) ranged from to 1.8. There was a significant positive correlation between shell height and both shell width and length of aperture (p<0.001). The same relation was clearly indicated between shell width and length of aperture. Also, when the aperture length increased the ratio between height and width increased (p<0.05). While, the following ratios (H/W), (A/H) and (A/W) remained somewhat constant irrespective to the number of whorls. There was a positive correlation between number of whorls and each of aperture length, shell length and shell height. On maintaining L. natalensis in different pH values, the results showed that at pH 3 and pH 11, all snails maintained at these pH values died after one day of maintenance. While snails survived and laid eggs in the range of pH 5-9.

  6. Natural prevalence in Cuban populations of the lymnaeid snail Galba cubensis infected with the liver fluke Fasciola hepatica: small values do matter.

    PubMed

    Vázquez, Antonio A; Sánchez, Jorge; Alba, Annia; Pointier, Jean-Pierre; Hurtrez-Boussès, Sylvie

    2015-11-01

    Natural infections of lymnaeid snails by Fasciola hepatica are of primary importance to study transmission. Also, infected snails in the field can be used to explore the existing compatibility in host-parasite interactions. This paper aimed to describe the infection rate of Galba cubensis populations in fasciolosis transmission areas. Eight sites were sampled in western Cuba and 24 infected snails at six sites were found. The mean prevalence was 2.94% and the maximum value was 11.4%. The intensity of parasite infection was assessed as the number of rediae inside a single snail. High variation within the sites examined was observed, but a maximum of 76 rediae was recovered from one individual. Although the presence of two other trematode families (Schistosomatidae and Paramphistomatidae) was discovered in dissected individuals, no co-infection with F. hepatica was observed. This is the first time a study of natural prevalence of F. hepatica infection is carried out in Cuba, considered a hyper endemic country for bovine fasciolosis. Our results suggest that fasciolosis transmission may occur even when the number of infected snails remains relatively low.

  7. Environmental Persistence and Infectivity of Oocysts of Two Species of Gregarines, Blabericola migrator and Blabericola cubensis (Apicomplexa: Eugregarinida: Blabericolidae), Parasitizing Blaberid Cockroaches (Dictyoptera: Blaberidae).

    PubMed

    Clopton, Richard E; Steele, Shelby M; Clopton, Debra T

    2016-04-01

    For apicomplexan parasites using an oral-fecal transmission route with significant environmental exposure, the environmental persistence and infectivity of the oocyst has a direct impact on local infection dynamics, including the ability to withstand extended periods without readily available hosts. Herein we quantify the environmental persistence and infectivity of the oocysts of 2 septate gregarine species at controlled temperature and humidity and demonstrate that they can persist over multiple generational time spans. Species of Blabericola generally complete their endogenous life cycles from oocyst to oocyst within 10 days. The median residual environmental oocyst lifetime for Blabericola oocysts in this study is 21-28 days, but a significant number of oocysts of Blabericola migrator persisted and remained infective in the environment for up to 39 days while those of Blabericola cubensis persisted and remained infective for up to 92 days. Although long-lived relative to their own generational time, the oocysts of Blabericola species infecting cockroaches are short-lived relative to gregarines infecting tenebrionid beetles. For these gregarines, oocysts can persist in the environment and remain infective for up to 787 days. Mechanistically, environmental persistence and infectivity are probably energy-limited phenomena related to the amount of stored amylopectin and the basal metabolic rate of quiescent oocysts.

  8. /sup 45/Ca uptake from water by snails (Lymnaea vulgaris) in control and detergent-polluted samples

    SciTech Connect

    Misra, V.; Lal, H.; Viswanathan, P.N.; Murti, C.R.

    1984-02-01

    A biostatic assay method involving /sup 45/Ca uptake into shells and tissues of snails (Lymnaea vulgaris) in 72 hr was developed to follow the effect of detergent-polluted water on ecosystems. There was a marked decrease in the /sup 45/Ca uptake by shells and tissues of linear alkyl benzene sulfonate-exposed animals as compared to controls. No change in /sup 45/Ca uptake was observed in dead shells, thereby excluding the possibility of passive exchange.

  9. First report of Lymnaea cousini Jousseaume, 1887 naturally infected with Fasciola hepatica (Linnaeus, 1758) (Trematoda: Digenea) in Machachi, Ecuador.

    PubMed

    Villavicencio, Angel; Vasconcellos, Mauricio Carvalho de

    2005-11-01

    We report the first finding of Lymnaea cousini naturally infected with Fasciola hepatica in Ecuador. A sample of 70 snails was collected in April 2005 from a wetland located in a valley at approximately 3000 m a.s.l., near the locality of Machachi, Pichincha Province. The prevalence of natural infection in L. cousini was 31.43%, which is the highest value ever recorded for naturally infected lymnaeid species.

  10. Characterisation of fascioliasis lymnaeid intermediate hosts from Chile by DNA sequencing, with emphasis on Lymnaea viator and Galba truncatula.

    PubMed

    Artigas, Patricio; Bargues, M Dolores; Mera y Sierra, Roberto L; Agramunt, Veronica H; Mas-Coma, Santiago

    2011-12-01

    In South America, Fasciola hepatica infection poses serious health problems in both humans and livestock. In Chile, the medical impact appears yearly stable and mainly concentrated in central regions, where the veterinary problem is highlighted by higher animal prevalences. Studies were undertaken by rDNA ITS-2 and ITS-1 and mtDNA cox1 sequencing to clarify the specific status of the lymnaeids, their geographical distribution and fascioliasis transmission capacity in Chile, by comparison with other American countries and continents. Results change the lymnaeid scenario known so far. The lymnaeid fauna of mainland Chile shows to be poor, including only two authochthonous species, Lymnaea viator and Pectinidens diaphana, and a third introduced species of Palaearctic origin Galba truncatula. Both Lymnaea lebruni and Lymnaea patagonica proved to be synonyms of P. diaphana. G. truncatula appears to have always been confused with L. viator and seems distributed from Región VI to Región IX, overlapping with human endemic areas. DNA sequencing results suggest that the absence of correlation between remote sensing data and disease prevalences could be due to transmission capacity differences between L. viator and G. truncatula. Results furnish a new baseline on which to undertake future appropriate studies on transmission, epidemiology and control.

  11. An expressed sequence tag survey of gene expression in the pond snail Lymnaea stagnalis, an intermediate vector of trematodes [corrected].

    PubMed

    Davison, A; Blaxter, M L

    2005-05-01

    The pond snail Lymnaea stagnalis is an intermediate vector for the liver fluke Fasciola hepatica, a common parasite of ruminants and humans. Yet, despite being a disease of medical and economic importance, as well as a potentially useful comparative tool, the genetics of the relationship between Lymnaea and Fasciola has barely been investigated. As a complement to forthcoming F. hepatica expressed sequence tags (ESTs), we generated 1320 ESTs from L. stagnalis central nervous system (CNS) libraries. We estimate that these sequences derive from 771 different genes, of which 374 showed significant similarity to proteins in public databases, and 169 were similar to ESTs from the snail vector Biomphalaria glabrata. These L. stagnalis ESTs will provide insight into the function of the snail CNS, as well as the molecular components of behaviour and response to parasitism. In the future, the comparative analysis of Lymnaea/Fasciola with Biomphalaria/Schistosoma will help to understand both conserved and divergent aspects of the host-parasite relationship. The L. stagnalis ESTs will also assist gene prediction in the forthcoming B. glabrata genome sequence. The dataset is available for searching on the world-wide web at http://zeldia.cap.ed.ac.uk/mollusca.html.

  12. DIFFERENTIAL TRACER COUPLING BETWEEN PAIRS OF IDENTIFIED NEURONES OF THE MOLLUSC LYMNAEA STAGNALIS

    PubMed

    Ewadinger; Syed; Lukowiak; Bulloch

    1994-07-01

    Electrical coupling is a common means of cell-to-cell communication in both neuronal and non-neuronal tissues (Lowenstein, 1985). Within the nervous system, many electrically coupled neurones exhibit dye coupling (Bennett, 1973; Stewart, 1978; Glantz and Kirk, 1980; Spencer and Satterlie, 1980; Fraser and Heitler, 1993); however, some electrically coupled cells do not dye-couple (Audesirk et al. 1982; Murphy et al. 1983; Berdan, 1987; Robinson et al. 1993; Veenstra et al. 1993). Electrical coupling and dye coupling, often considered in parallel, are in fact two different parameters that can vary independently (e.g. Audesirk et al. 1982; Perez-Armendariz et al. 1991). The giant identified neurones of pulmonate and opisthobranch molluscs have frequently been used for studies of neuronal communication and its plasticity (Winlow and McCrohan, 1987; Bulloch, 1989). In the present study, we explored the relationship between electrical and tracer coupling in both strongly and weakly coupled pairs of molluscan neurones. Specifically, we examined electrically coupled, identified neurones in a freshwater pond snail, Lymnaea stagnalis L., and tested for tracer coupling with Lucifer Yellow CH and biocytin. The cells examined were the strongly electrically coupled neurones, visceral dorsal 1 (VD1) and right parietal dorsal 2 (RPD2) (Boer et al. 1979; Benjamin and Pilkington, 1986), and the weakly coupled neurones, left buccal 1 (LB1) and right buccal 1 (RB1) (Benjamin and Rose, 1979). The use of these particular neurones made it possible to compare electrical coupling with tracer coupling in the molluscan central nervous system (CNS). All experiments were performed on laboratory-bred Lymnaea stagnalis (Mollusca, Pulmonata), maintained as previously described (Ridgway et al. 1991). The CNS was dissected from mature animals (16­18 mm shell length) and pinned to the silicone rubber (RTV 616 GE) base of a recording dish in normal saline (51.3 mmol l-1 NaCl, 1.7 mmol l-1 KCl, 4

  13. Family of prohormone convertases in Lymnaea: characterization of two alternatively spliced furin-like transcripts and cell-specific regulation of their expression.

    PubMed

    Spijker, S; Smit, A B; Sharp-Baker, H E; Van Elk, R; Van Kesteren, E R; Van Minnen, J; Kurosky, A; Geraerts, W P

    1999-11-15

    The majority of neuropeptides in Lymnaea stagnalis are proteolytically processed from larger precursors at sites composed of single or multiple basic amino acid residues. Previous studies have identified several putative prohormone convertases in the brain of Lymnaea. To characterize the complete family, we undertook three independent approaches: reverse-transcribed polymerase chain reaction screening, and low-stringency cDNA and genomic library screenings. The central nervous system cDNA library screening yielded two cDNAs encoding Lfurin1 and its variant form, Lfurin1-X. Both proteins show the characteristic organization of (human) furin with a putative catalytic domain, a P domain, a Cys-rich domain, a transmembrane domain, and a cytoplasmic tail. Lfurin1 and Lfurin1-X are identical, apart from a putative alternatively spliced noncatalytic luminal protein domain, which is present exclusively in Lfurin1-X. In situ hybridization revealed that the Lfur1 gene is expressed throughout the Lymnaea brain, but that the level varies considerably from one neuron to another. Quantitative analysis of the expression level of the two alternatively spliced transcripts revealed that it is neuron type-specifically regulated. This probably indicates the functional importance of noncatalytic luminal protein domains in these enzymes. In addition, our findings suggest that apart from the identified convertases LPC2, Lfurin1/Lfurin1-X, and Lfurin2, additional prohormone convertase diversity is either not present or present only at low levels in the Lymnaea brain. Alternatively, additional prohormone convertases could exist with a lower degree of sequence conservation than the other Lymnaea prohormone convertase members. From our findings, it appears that the majority of prohormone processing in Lymnaea is carried out by the three thus far identified types of Kex2-related prohormone convertases despite the large number of neuropeptide precursors and diverse multiple basic cleavage

  14. Molluscicidal activity of Sapindus mukorossi and Terminalia chebula against the freshwater snail Lymnaea acuminata.

    PubMed

    Upadhyay, Aparna; Singh, D K

    2011-04-01

    The molluscicidal activity of Sapindus mukorossi and Terminalia chebula fruit powder against the vector snail Lymnaea acuminata was time and concentration dependent. The molluscicidal activity of T. chebula fruit powder (96 h LC(50):93.59 mg L(-1)) was more pronounced than that of S. mukorossi fruit powder (96 h LC(50):119.57 mg L(-1)). Ethanolic extracts of S. mukorossi and T. chebula fruit powder were more toxic than their other organic solvent extracts. The molluscicidal activity of ethanolic extract of S. mukorossi fruit powder (24h LC(50):2.75 mg L(-1)) was more effective than the ethanolic extract of T. chebula fruit powder (24h LC(50):124.06 mg L(-1)). The 96 h LC(50) of column-purified fraction of S. mukorossi fruit powder was 5.43 mg L(-1) whereas those of T. chebula fruit powder was 7.49 mg L(-1). Column, thin layer and high performance liquid chromatography analysis demonstrates that the active molluscicidal component in S. mukorossi and T. chebula is saponin (96 h LC(50):1.31 mg L(-1)) and tannic acid (96 h LC(50):1.64 mg L(-1)), respectively. These plants may be used as potent source of molluscicides against the snail L. acuminata.

  15. Millimeter waves thermally alter the firing rate of the Lymnaea pacemaker neuron

    SciTech Connect

    Alekseev, S.I.; Kochetkova, N.V.; Ziskin, M.C.; Bolshakov, M.A.

    1997-05-01

    The effects of millimeter waves (mm-waves, 75 GHz) and temperature elevation on the firing rate of the BP-4 pacemaker neuron of the pond snail Lymnaea stagnalis were studied by using microelectrode techniques. The open end of a rectangular waveguide covered with a thin Teflon film served as a radiator. Specific absorption rates (SARs), measured in physiological solution at the radiator outlet, ranged from 600 to 4,200 W/kg, causing temperature rises from 0.3 to 2.2 C, respectively. Irradiation at an SAR of 4,200 W/kg caused a biphasic change in the firing rate, i.e., a transient decrease in the firing rate followed by a gradual increase to a new level that was 68 {+-} 21% above control. The biphasic changes in the firing rate were reproduced by heating under the condition that the magnitude (2 C) and the rate of temperature rise were equal to those produced by the irradiation. The addition of 0.05 mM of ouabain caused the disappearance of transient responses of the neuron to the irradiation. It was shown that the rate of temperature rise played an important role in the development of a transient neuronal response. The threshold stimulus for a transient response of the BP-4 neutron found in warming experiments was a temperature rise of 0.0025 C/s.

  16. Optimizing the design of a reproduction toxicity test with the pond snail Lymnaea stagnalis.

    PubMed

    Charles, Sandrine; Ducrot, Virginie; Azam, Didier; Benstead, Rachel; Brettschneider, Denise; De Schamphelaere, Karel; Filipe Goncalves, Sandra; Green, John W; Holbech, Henrik; Hutchinson, Thomas H; Faber, Daniel; Laranjeiro, Filipe; Matthiessen, Peter; Norrgren, Leif; Oehlmann, Jörg; Reategui-Zirena, Evelyn; Seeland-Fremer, Anne; Teigeler, Matthias; Thome, Jean-Pierre; Tobor Kaplon, Marysia; Weltje, Lennart; Lagadic, Laurent

    2016-11-01

    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.

  17. Molluscicidal activity of Saraca asoca and Thuja orientalis against the fresh water snail Lymnaea acuminata.

    PubMed

    Singh, Arundhati; Singh, V K

    2009-10-14

    The molluscicidal activity of bark powder of Saraca asoca, leaf powder of Thuja orientalis against the snail Lymnaea acuminata was studied. The molluscicidal activity of all the plant products was found to be both time and concentration dependent. The 96 h LC(50) of T. orientalis leaf powder against L. acuminata was 250.5mg/l. Ethanol extracts were more toxic than other organic extracts. The ethanol extract of T. orientalis leaf (24h LC(50): 32.74 mg/l) was more effective than that of S. asoca bark (24h LC(50): 82.38 mg/l). The 24h LC(50) of column purified fraction of T. orientalis leaf and S. asoca bark powder was 29.25 and 64.89 mg/l, respectively. Saponin and thujone were identified as active molluscicide components in the bark of S. asoca and leaf of T. orientalis, respectively. The product of S. asoca and T. orientalis may be used as potent molluscicides.

  18. Crystal structures of Lymnaea stagnalis AChBP in complex with neonicotinoid insecticides imidacloprid and clothianidin

    PubMed Central

    Ihara, Makoto; Okajima, Toshihide; Yamashita, Atsuko; Oda, Takuma; Hirata, Koichi; Nishiwaki, Hisashi; Morimoto, Takako; Akamatsu, Miki; Ashikawa, Yuji; Kuroda, Shun’ichi; Mega, Ryosuke; Kuramitsu, Seiki; Sattelle, David B.

    2008-01-01

    Neonicotinoid insecticides, which act on nicotinic acetylcholine receptors (nAChRs) in a variety of ways, have extremely low mammalian toxicity, yet the molecular basis of such actions is poorly understood. To elucidate the molecular basis for nAChR–neonicotinoid interactions, a surrogate protein, acetylcholine binding protein from Lymnaea stagnalis (Ls-AChBP) was crystallized in complex with neonicotinoid insecticides imidacloprid (IMI) or clothianidin (CTD). The crystal structures suggested that the guanidine moiety of IMI and CTD stacks with Tyr185, while the nitro group of IMI but not of CTD makes a hydrogen bond with Gln55. IMI showed higher binding affinity for Ls-AChBP than that of CTD, consistent with weaker CH–π interactions in the Ls-AChBP–CTD complex than in the Ls-AChBP–IMI complex and the lack of the nitro group-Gln55 hydrogen bond in CTD. Yet, the NH at position 1 of CTD makes a hydrogen bond with the backbone carbonyl of Trp143, offering an explanation for the diverse actions of neonicotinoids on nAChRs. PMID:18338186

  19. Reproductive impacts of tributyltin (TBT) and triphenyltin (TPT) in the hermaphroditic freshwater gastropod Lymnaea stagnalis.

    PubMed

    Giusti, Arnaud; Barsi, Alpar; Dugué, Maël; Collinet, Marc; Thomé, Jean-Pierre; Joaquim-Justo, Célia; Roig, Benoit; Lagadic, Laurent; Ducrot, Virginie

    2013-07-01

    Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment, they have mainly been tested separately for their effects on snail reproduction. Because large discrepancies in experimental conditions occurred in these tests, the present study aimed to compare the relative toxicity of TBT and TPT under similar laboratory conditions in the range of 0 ng Sn/L to 600 ng Sn/L. Tests were performed on the simultaneous hermaphrodite Lymnaea stagnalis, a freshwater snail in which effects of TPT were unknown. Survival, shell length, and reproduction were monitored in a 21-d semistatic test. Frequency of abnormal eggs was assessed as an additional endpoint. Triphenyltin hampered survival while TBT did not. Major effects on shell solidity and reproduction were observed for both compounds, reproductive outputs being more severely hampered by TBT than by TPT. Considering the frequency of abnormal eggs allowed increasing test sensitivity, because snail responses to TBT could be detected at concentrations as low as 19 ng Sn/L. However, the putative mode of action of the 2 compounds could not be deduced from the structure of the molecules or from the response of apical endpoints. Sensitivity of L. stagnalis to TBT and TPT was compared with the sensitivity of prosobranch mollusks with different habitats and different reproductive strategies.

  20. Mucus secretion by the freshwater snail Lymnaea stagnalis limits aluminum concentrations of the aqueous environment

    SciTech Connect

    Jugdaohsingh, R.; Thompson, R.P.H.; Powell, J.J.; Campbell, M.M.; Mccrohan, C.R.; White, K.N.

    1998-09-01

    Extracellular mucopolysaccharide (EPS) is a significant component in many waters. Its role in the cycling and mobilization of metals is unclear. In vitro studies were conducted to examine the influence of EPS, secreted by the freshwater pond snail, Lymnaea stagnalis, on soluble water Al concentrations at near-neutral pH. Snails maintained in aerated water of known ion content and added aluminum reduced Al in solution as compared to controls. Although snails accumulated Al into soft tissue, this only accounted for a small percentage of the total reduction. The remaining Al was recovered following acidification of the water. This observation was attributed to pedal EPS secreted by L. stagnalis which is chiefly insoluble and substrate bound. The Al that remained in solution was more labile, possibly due to the influence of soluble EPS. Further experiments with isolated EPS, confirmed that this poorly soluble film binds and reduces Al in solution. The influence of EPS on the solution chemistry and bioavailability of Al and possibly other metals may be important in natural waters.

  1. Critical Period of Memory Enhancement during Taste Avoidance Conditioning in Lymnaea stagnalis

    PubMed Central

    Sunada, Hiroshi; Lukowiak, Ken; Sakakibara, Manabu

    2013-01-01

    The present study investigated the optimal training procedure leading to long-lasting taste avoidance behavior in Lymnaea. A training procedure comprising 5 repeated pairings of a conditional stimulus (CS, sucrose), with an unconditional stimulus (US, a tactile stimulation to the animal’s head), over a 4-day period resulted in an enhanced memory formation than 10 CS-US repeated pairings over a 2-day period or 20 CS-US repeated pairings on a single day. Backward conditioning (US-CS) pairings did not result in conditioning. Thus, this taste avoidance conditioning was CS-US pairing specific. Food avoidance behavior was not observed following training, however, if snails were immediately subjected to a cold-block (4°C for 10 min). It was critical that the cold-block be applied within 10 min to block long-term memory (LTM) formation. Further, exposure to the cold-block 180 min after training also blocked both STM and LTM formation. The effects of the cold-block on subsequent learning and memory formation were also examined. We found no long lasting effects of the cold-block on subsequent memory formation. If protein kinase C was activated before the conditioning paradigm, snails could still acquire STM despite exposure to the cold-block. PMID:24098373

  2. Environmental versus anthropogenic effects on population adaptive divergence in the freshwater snail Lymnaea stagnalis.

    PubMed

    Bouétard, Anthony; Côte, Jessica; Besnard, Anne-Laure; Collinet, Marc; Coutellec, Marie-Agnès

    2014-01-01

    Repeated pesticide contaminations of lentic freshwater systems located within agricultural landscapes may affect population evolution in non-target organisms, especially in species with a fully aquatic life cycle and low dispersal ability. The issue of evolutionary impact of pollutants is therefore conceptually important for ecotoxicologists. The impact of historical exposure to pesticides on genetic divergence was investigated in the freshwater gastropod Lymnaea stagnalis, using a set of 14 populations from contrasted environments in terms of pesticide and other anthropogenic pressures. The hypothesis of population adaptive divergence was tested on 11 life-history traits, using Q(ST)-F(ST) comparisons. Despite strong neutral differentiation (mean F(ST) = 0.291), five adult traits or parameters were found to be under divergent selection. Conversely, two early expressed traits showed a pattern consistent with uniform selection or trait canalization, and four adult traits appeared to evolve neutrally. Divergent selection patterns were mostly consistent with a habitat effect, opposing pond to ditch and channel populations. Comparatively, pesticide and other human pressures had little correspondence with evolutionary patterns, despite hatching rate impairment associated with global anthropogenic pressure. Globally, analyses revealed high genetic variation both at neutral markers and fitness-related traits in a species used as model in ecotoxicology, providing empirical support for the need to account for genetic and evolutionary components of population response in ecological risk assessment.

  3. NCS-1 differentially regulates growth cone and somata calcium channels in Lymnaea neurons.

    PubMed

    Hui, Kwokyin; Feng, Zhong-Ping

    2008-02-01

    Local voltage-gated calcium channels, which regulate intracellular Ca2+ levels by allowing Ca2+ influx, play an important role in guiding and shaping growth cones, and in regulating the outgrowth and branching of neurites. Therefore, elucidating the mechanisms that regulate the biophysical properties of whole-cell calcium currents in the growth cones and somata of growing neurons is important to improving our understanding of neuronal development and regeneration. In this study, taking advantage of the large size of the pedal A (PeA) neurons in Lymnaea stagnalis, we compared the biophysical properties of somata and growth cone whole-cell calcium channel currents using Ba2+ and Ca2+ as current carriers. We found that somata and growth cone currents exhibit similar high-voltage activation properties. However, Ba2+ and Ca2+ currents in growth cones and somata are differentially affected by a dominant-negative peptide containing the C-terminal amino acid sequence of neuronal calcium sensor-1 (NCS-1). The peptide selectively reduces the peak and sustained components of current densities and the slope conductance in growth cones, and shifts the reversal potential of the growth cone currents to more hyperpolarized voltages. In contrast, the peptide had no significant effect on the somata calcium channels. Thus, we conclude that NCS-1 differentially modulates Ca2+ currents in the somata and growth cones of regenerating neurons, and may serve as a key regulator to facilitate the growth cone calcium channel activity.

  4. Protein kinase C mediates memory consolidation of taste avoidance conditioning in Lymnaea stagnalis.

    PubMed

    Takigami, Satoshi; Sunada, Hiroshi; Lukowiak, Ken; Kuzirian, Alan M; Alkon, Daniel L; Sakakibara, Manabu

    2014-05-01

    In Lymnaea stagnalis, in order to obtain a 10 min short-term memory (STM) of taste avoidance conditioning (TAC) at least 10 paired presentations of a conditioned stimulus (CS), sucrose, and an unconditioned stimulus (US), tactile stimulation to the animal's head, are required. Pre-exposure of snails to the protein kinase C (PKC) α and ε activator bryostatin (Bryo) facilitated STM formation in that only 5 paired CS-US trials were required. Typically 20 paired presentations of the CS-US are required for formation of STM and LTM. However, 20 paired presentations do not result in STM or LTM if snails are pre-incubated with a PKC inhibitor, Ro-32-0432. We also found that LTM lasting longer than 48 h was acquired with Bryo incubation for 45 min even after termination of the conditioning paradigm. These data suggest that activation of the α and ε isozymes of PKC is crucially involved in the formation of LTM and provide further support for a mechanism that has been conserved across the evolution of species ranging from invertebrate molluscs to higher mammals.

  5. A two-neuron system for adaptive goal-directed decision-making in Lymnaea

    PubMed Central

    Crossley, Michael; Staras, Kevin; Kemenes, György

    2016-01-01

    During goal-directed decision-making, animals must integrate information from the external environment and their internal state to maximize resource localization while minimizing energy expenditure. How this complex problem is solved by the nervous system remains poorly understood. Here, using a combined behavioural and neurophysiological approach, we demonstrate that the mollusc Lymnaea performs a sophisticated form of decision-making during food-searching behaviour, using a core system consisting of just two neuron types. The first reports the presence of food and the second encodes motivational state acting as a gain controller for adaptive behaviour in the absence of food. Using an in vitro analogue of the decision-making process, we show that the system employs an energy management strategy, switching between a low- and high-use mode depending on the outcome of the decision. Our study reveals a parsimonious mechanism that drives a complex decision-making process via regulation of levels of tonic inhibition and phasic excitation. PMID:27257106

  6. A two-neuron system for adaptive goal-directed decision-making in Lymnaea.

    PubMed

    Crossley, Michael; Staras, Kevin; Kemenes, György

    2016-06-03

    During goal-directed decision-making, animals must integrate information from the external environment and their internal state to maximize resource localization while minimizing energy expenditure. How this complex problem is solved by the nervous system remains poorly understood. Here, using a combined behavioural and neurophysiological approach, we demonstrate that the mollusc Lymnaea performs a sophisticated form of decision-making during food-searching behaviour, using a core system consisting of just two neuron types. The first reports the presence of food and the second encodes motivational state acting as a gain controller for adaptive behaviour in the absence of food. Using an in vitro analogue of the decision-making process, we show that the system employs an energy management strategy, switching between a low- and high-use mode depending on the outcome of the decision. Our study reveals a parsimonious mechanism that drives a complex decision-making process via regulation of levels of tonic inhibition and phasic excitation.

  7. Effects of Fasciola gigantica experimental infection on some inorganic elements in the snail host Lymnaea natalensis.

    PubMed

    Mostafa, Osama Mohammad Sayed

    2008-04-01

    Flame atomic absorption spectrometry was performed to determine the alteration in the concentrations of metallic ion Pb, Zn, K, Na, Fe, Cu and Co in the soft parts of the Lymnaea natalensis snails shedding Fasciola gigantica cercariae and to determine the alteration in the concentration of Ca in the soft parts and shells of the same snails. The Co was found to be present at concentration level below the detection limits of the analytical method used. Regarding detected elements, three elements Zn, K and Cu were found to be present at significantly higher concentrations in cercariae-shedding snails compared with uninfected snails. Two elements, Pb and Na, showed significant decrease in cercariae-shedding snails compared to uninfected ones. The concentration of Fe showed non-significant increase. The results showed significant lowering in the calcium content of the shells and soft parts of cercariae-shedding snails relative to the calcium content in the uninfected ones. The obtained results and the hypothesis of hypercalcification in shells of infected snails were discussed.

  8. Rearing of Lymnaea columella (Say, 1817), intermediate host of Fasciola hepatica (Linnaeus, 1758).

    PubMed

    Pereira de Souza, C; Magalhães, K G

    2000-01-01

    The intermediate host of Fasciola hepatica, Lymnaea columella, collected in Belo Horizonte, Minas Gerais, Brazil, was reared in our laboratory. The aim of the current study was to standardize a rearing and maintenance technique. Two kinds of diet were tested: fresh lettuce (A) and rodent ration + 10% CaCO3 plus fresh lettuce (B). The age for the beginning of oviposition ranged from 27 to 57 days. Ten days after oviposition at 24.7 degrees C, 100% eclosion occurred. The complete life cycle varied from 37 to 67 days. The average numbers of eggs per egg mass were 26.3 and 31.1 with diets (A) and (B), respectively. The lettuce and ration fed snails presented a increased growth although the difference was not statistically significant (p > 0.05). The mortality rate varied from 40 to 64% after 90 days. The maximum longevity was 183 days, 21.5 mm length and 11 mm wide. The methodology to mass breed and maintain these snails was found to be suitable in the laboratory

  9. Influence of photon beam irradiation on Lymnaea natalensis snails infected with Fasciola gigantica.

    PubMed

    Said, Doaa E; Rostom, Yousry A

    2006-04-01

    Lymnaea natalensis is the intermediate host of Fasciola gigantica in Egypt. The effect of photon beam irradiation on the ability of the laboratory reared L. natalensis to support the larval development of F. gigantica has been studied. 120 snails were divided into two groups: The control infected non irradiated group (GI) and the experimental infected irradiated group (GII). The later group was subdivided into two subgroups: GIIa: snails irradiated before infection and GIIb: snails irradiated after infection. Photon beam irradiation had non significant effect on the survival rate between the all groups at the 30th day post infection. The life span, the number of infected snails and the length of the shedding period were significantly decreased in the two irradiated subgroups than the control group. The effect was more obvious on GIIb without significant difference. The number of metacercariae significantly decreased in the 2 irradiated subgroups than the control one. Also, it was significantly decreased in GIIb when compared with GIIa. So, photon beam irradiation has a great role on retarding larval development of F. gigantica inside the snail. This opens the way to a new strategy for fascioliasis control of in Egypt.

  10. Fasciola gigantica: larval productivity of three different miracidial isolates in the snail Lymnaea truncatula.

    PubMed

    Dar, Y; Vignoles, P; Rondelaud, D; Dreyfuss, G

    2003-03-01

    Bimiracidial infections of Lymnaea truncatula with three isolates of Fasciola gigantica, originating from China, Egypt and Madagascar, were carried out to determine the effect of geographic origin of the parasite on the larval productivity of redial generations. The prevalences of experimental infections in snails exposed to strains from Madagascar, China and Egypt were 20.8%, 60.0% and 80.0%, respectively. At day 49 post-exposure (p.e.), the total number of free rediae in snails infected with the Egyptian isolate was significantly higher than that recorded in the Madagascan group. On the other hand, at day 49 p.e., the majority of cercariae in the Chinese and Egyptian groups were produced by R2a rediae (70.6% and 66.6% of cercariae produced by all live rediae), while, in the Madagascan group, the cercariae were produced mainly by the first redial generation. Snails infected with the Egyptian isolate of miracidia developed more live rediae and, consequently, could produce a higher number of cercariae. As a result, L. truncatula snails were highly adapted to infections with the Egyptian and Chinese isolates of F. gigantica.

  11. Larval trematode infections in Lymnaea glabra populations living in the Brenne Regional Natural Park, central France.

    PubMed

    Rondelaud, Daniel; Vignoles, Philippe; Dreyfuss, Gilles

    2015-01-01

    Lymnaea glabra is known to be a natural intermediate host of two flukes, Calicophoron daubneyi and Fasciola hepatica, in central France. But it can also sustain larval development of other digeneans. Adult snails were thus collected from 206 habitats in 2014 and 2015 to identify parasite species and determine the prevalence of each digenean infection in relation to the five types of snail habitats. Seven digenean species were noted in 321 infected snails (out of 17,647 L. glabra). Snails with F. hepatica or C. daubneyi were found in 14.5% and 12.6% of habitats, respectively. Percentages were lower for snails with Opisthoglyphe ranae (5.8%), Haplometra cylindracea (5.3%) and were less than 5% for those infected with Echinostoma revolutum, Notocotylus sp. or Plagiorchis sp. Prevalence noted for each parasite species varied with the type of habitat. The number of species in L. glabra was lower than that found in G. truncatula from the same region (7 instead of 10). The distribution and prevalence of each digenean species were thus dependent on the type and location of each snail habitat. © D. Rondelaud et al., published by EDP Sciences, 2015.

  12. Lymnaea glabra: progressive increase in susceptibility to Fasciola hepatica through successive generations of experimentally infected snails.

    PubMed

    Rondelaud, D; Teukeng, F F Djuikwo; Vignoles, P; Dreyfuss, G

    2015-07-01

    Experimental infections of Lymnaea glabra (two populations) with Fasciola hepatica were carried out during seven successive snail generations, to determine if prevalence and intensity of snail infection increased over time through descendants of snails already infected with F. hepatica. Controls were descendants coming from uninfected parents and infected according to the same protocol. No larval forms were found in the bodies of control snails coming from uninfected parents. In contrast, prevalence and intensity of F. hepatica infection in snails originating from infected parents progressively increased from the F2 or F3 to the F6 generation of L. glabra. In another experiment carried out with the F7 generations of L. glabra and a single generation of Galba truncatula (as controls), the prevalence of F. hepatica infection and the total number of cercariae were lower in L. glabra (without significant differences between both populations). If the number of cercariae shed by infected snails was compared to overall cercarial production noted in snails containing cercariae but dying without emission, the percentage was greater in G. truncatula (69% instead of 52-54% in L. glabra). Even if most characteristics of F. hepatica infection were lower in L. glabra, prevalence and intensity of parasite infection increased with snail generation when tested snails came from infected parents. This mode of snail infection with F. hepatica suggests an explanation for cases of fasciolosis occurring in cattle-breeding farms where paramphistomosis is lacking and G. truncatula is absent.

  13. Comparative toxicity of Paraquat herbicide and some plant extracts in Lymnaea natalensis snails.

    PubMed

    Bakry, Fayez A; Eleiwa, Mona E; Taha, Samir A; Ismil, Somya M

    2016-01-01

    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. © The Author(s) 2013.

  14. Larval development of Fasciola hepatica in experimental infections: variations with populations of Lymnaea truncatula.

    PubMed

    Vignoles, P; Dreyfuss, G; Rondelaud, D

    2002-06-01

    A retrospective study was undertaken on 70 French populations of Lymnaea truncatula experimentally infected with Fasciola hepatica to determine whether or not susceptibility of snails to infection influenced redial and cercarial production. Results were compared with those obtained from two control populations, known for prevalences higher than 60% when experimentally infected with F. hepatica. In the 70 other populations examined, the prevalences ranged from 2 to 75%. In 55 of these populations, where the prevalence was more than 20%, a high proportion (50.1-56.8%) of snails died after cercarial shedding, whereas in the other groups (non-shedding snails with the most differentiated larvae being free cercariae, rediae containing cercariae, immature rediae, or sporocysts, respectively), snail death was significantly less. In 11 populations, where the prevalence values were 5-19%, only 14% of snails died after cercarial shedding, whereas snails with free cercariae, rediae with cercariae, or immature rediae showed significant increases in snail mortality. In the remaining four snail populations, with prevalences of less than 5%, the most differentiated larval forms were only immature rediae and/or sporocysts. Overall, the number of rediae containing cercariae significantly decreased with decreasing prevalence values. The low prevalence of experimental infection in several populations of snails might be explained by the occurrence of natural infections with miracidia originating from a mammalian host other than cattle, and/or by genetic variability in the susceptibility of snails to infection.

  15. Cercarial productivity of Fasciola hepatica in Lymnaea truncatula during usual and unusual development of redial generations.

    PubMed

    Augot, D; Rondelaud, D

    2001-08-01

    Single-miracidium infections of Lymnaea truncatula by Fasciola hepatica were carried out to determine the cercarial productivity of each redial generation when the first-appearing mother redia (R1a redia) normally developed (usual development of redial generations) or quickly died (unusual development). In both developmental patterns of infection, the number of morulae was significantly higher in the second-appearing mother rediae (R1b group) than in either the daughter rediae from R1a rediae (R2a group) or the rediae from subsequent groups (R2b/R3a). The live R1a group did not produce cercariae. The percentages of cercariae produced by the R1b, R2a, and R2b/R3a groups were 28.2%, 62.8%, and 8.9% when the development of redial generations was usual. In contrast, in an unusual development, they were 69.3%, 20.3%, and 10.2%, respectively. Cercarial production until day 63 post-exposure was essentially provided by the R2a rediae, when the development of redial generations was usual, and by the R1b rediae when it was unusual.

  16. Larval trematode infections in Lymnaea glabra populations living in the Brenne Regional Natural Park, central France

    PubMed Central

    Rondelaud, Daniel; Vignoles, Philippe; Dreyfuss, Gilles

    2015-01-01

    Lymnaea glabra is known to be a natural intermediate host of two flukes, Calicophoron daubneyi and Fasciola hepatica, in central France. But it can also sustain larval development of other digeneans. Adult snails were thus collected from 206 habitats in 2014 and 2015 to identify parasite species and determine the prevalence of each digenean infection in relation to the five types of snail habitats. Seven digenean species were noted in 321 infected snails (out of 17,647 L. glabra). Snails with F. hepatica or C. daubneyi were found in 14.5% and 12.6% of habitats, respectively. Percentages were lower for snails with Opisthoglyphe ranae (5.8%), Haplometra cylindracea (5.3%) and were less than 5% for those infected with Echinostoma revolutum, Notocotylus sp. or Plagiorchis sp. Prevalence noted for each parasite species varied with the type of habitat. The number of species in L. glabra was lower than that found in G. truncatula from the same region (7 instead of 10). The distribution and prevalence of each digenean species were thus dependent on the type and location of each snail habitat. PMID:26692260

  17. Development of Fasciola hepatica in Lymnaea columella infected with miracidia derived from cattle and marmoset infections.

    PubMed

    Mendes, E A; Lima, W S; de Melo, A L

    2008-03-01

    The development of Fasciola hepatica from two species of definitive hosts, i.e. cattle (Bos taurus) and a marmoset (Callithrix penicillata) in the snail Lymnaea columella was determined based on the production of rediae and cercariae and snail survival rate. More rediae and cercariae at 60-74 days post-infection were produced by snails infected by cattle-derived miracidia (cattle group) than by those infected by marmoset-derived miracidia (marmoset group). Among the L. columella parasitized by the marmoset group, the survival rate and the percentage of positive snails were higher than among those parasitized by the cattle group. Eggs of F. hepatica released in cattle faeces were significantly bigger than those released in marmoset faeces. Miracidia originating from parasites that completed their development in cattle were more efficient in infecting the intermediate host. These results suggest that vertebrate-host origin influences the eggs produced by the parasite and the infection rates in the snail host L. columella.

  18. Estrogen-related fecundity reduction of Lymnaea ollula following Fasciola gigantica infection.

    PubMed

    Kumkate, Supeecha; Onmek, Nuttajit; Boonburapong, Bongkoj; Singhakaew, Sombut; Leardkamolkarn, Vijittra

    2009-12-01

    Infection by trematode parasites generally affects life history traits of their intermediate hosts. Reduction in life expectancy and reproductive capacity have previously been documented in Fasciola gigantica-infected Lymnaea ollula, but the influence of the endocrine system on this specific host–parasite interaction has not been previously examined. In the present study, we observed survival, growth pattern, and reproductive output of L. ollula following exposure to F. gigantica. Both the survival and the growth pattern of infected snails were similar to those of the non-infected control group. However, a significant difference was apparent in fecundity, as infected snails consistently showed lower levels of egg and embryo production throughout a 7-wk observation period. Semi-quantitative RT-PCR also revealed down-regulation of estrogen receptor expression in infected snails during the first 4 wk of infection. Nonetheless, the inhibition of estrogen signaling was transient, as they regained expression in the later phase of infection. It is, therefore, suggested that other hormones of the complex endocrine system may be involved in the reduced fecundity of L. ollula following F. gigantica infection.

  19. More efficient allopatric combinations of Fasciola hepatica and Lymnaea truncatula due to modification of redial development?

    PubMed

    Goumghar, M D; Dreyfuss, G; Rondelaud, D; Benlemlih, M; Cabaret, J

    2001-12-01

    Experimental infections of two susceptible French populations of Lymnaea truncatula (Courcelles and Saint Ours) with an allopatric (Fès, Morocco) or a semi-sympatric (Limoges, France) isolate of Fasciola hepatica miracidia were performed to determine the effect of allopatric miracidia on redial and cercarial production. In both populations, cercarial release was significantly greater in allopatric than in semi-sympatric snails. Compared to semi-sympatric snails, the examination of allopatric snails killed from day 14 to day 35 post-exposure demonstrated (1) a significant decrease after day 28 in the number of daughter rediae (R2a group) exiting from the first-appearing mother redia (R1a redia), and (2) the differentiation of numerous daughter rediae (R2b group) in the body of second-appearing mother rediae (R1b group). These experiments demonstrated that the exposure of L. truncatula to an allopatric isolate of miracidia disturbed the usual developmental pattern of redial generations and caused the formation of numerous R2b rediae. The authors hypothesized that the increase in cercarial release noted in allopatric snails would be assured by the rediae from the R2b group after their emergence from the body of R1b mother rediae.

  20. High sensitivity of spontaneous spike frequency to sodium leak current in a Lymnaea pacemaker neuron.

    PubMed

    Lu, T Z; Kostelecki, W; Sun, C L F; Dong, N; Pérez Velázquez, J L; Feng, Z-P

    2016-12-01

    The spontaneous rhythmic firing of action potentials in pacemaker neurons depends on the biophysical properties of voltage-gated ion channels and background leak currents. The background leak current includes a large K(+) and a small Na(+) component. We previously reported that a Na(+) -leak current via U-type channels is required to generate spontaneous action potential firing in the identified respiratory pacemaker neuron, RPeD1, in the freshwater pond snail Lymnaea stagnalis. We further investigated the functional significance of the background Na(+) current in rhythmic spiking of RPeD1 neurons. Whole-cell patch-clamp recording and computational modeling approaches were carried out in isolated RPeD1 neurons. The whole-cell current of the major ion channel components in RPeD1 neurons were characterized, and a conductance-based computational model of the rhythmic pacemaker activity was simulated with the experimental measurements. We found that the spiking rate is more sensitive to changes in the Na(+) leak current as compared to the K(+) leak current, suggesting a robust function of Na(+) leak current in regulating spontaneous neuronal firing activity. Our study provides new insight into our current understanding of the role of Na(+) leak current in intrinsic properties of pacemaker neurons. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  1. Echinostomatid larval stages in Lymnaea viatrix (Gastropoda: Pulmonata) from southwest Patagonia, Argentina.

    PubMed

    Prepelitchi, Lucila; de Núñez, Margarita Ostrowski

    2007-04-01

    The partial life cycle of an echinostomatid found in Lymnaea viatrix from Patagonia, Argentina, was experimentally clarified. Emerging cercariae were exposed to laboratory-reared specimens of Biomphalaria sp. Metacercariae obtained from both naturally and experimentally infected snails were force-fed to chicks. Specimens recovered from the chicks belong to Echinoparyphium sp. on the basis of morphological features. The studied species possesses 43 collar spines arranged in 4-4-27-4-4 at all stages, a cercariae with over 100 small corpuscles in the excretory system, a cercariae tail without finfolds, and a metacercariae with a thin cyst wall. The present species cannot be assigned to Echinoparyphium megacirrus despite their morphological similarity because of differences in the habitats of L. viatrix and the intermediate hosts of E. megacirrus, namely Chilina dombeiana, Diplodon chilensis, and Temnocephala chilensis. More information on some life cycle stages and on the ecology of the intermediate hosts is needed to clarify the taxonomic status of the parasite. This study represents the first detailed description of parasites other than Fasciola hepatica in L. viatrix from Argentina.

  2. Variability and frequent failure of lucifer yellow to pass between two electrically coupled neurons in Lymnaea stagnalis.

    PubMed

    Audesirk, G; Audesirk, T; Bowsher, P

    1982-07-01

    The electrically coupled giant neurosecretory neurons VD1 and RPD2 of Lymnaea stagnalis were found to have coupling coefficients ranging from ca. 0.1-0.6. When the fluoroescent dye Lucifer Yellow was injected intracellularly into one of the neurons, in most preparations no dye was observed to pass through into the coupled cell body or the process leading to it. There was no apparent correlation between the amount of dye coupling and the length of time allowed for diffusion of the dye in the cells. In eight preparations, the electrical coupling coefficient was measured before dye was injected. There was no correlation between dye coupling and the electrical coupling coefficient.

  3. Fasciola immature stages sought in Lymnaea species and Biomphalaria species in the water bodies of Dakahlia Governorate.

    PubMed

    el-Shazly, Atef M; Helmy, Moshira M F; Haridy, Fouad M; el-Sharkawy, Eman M A; Morsy, Tosson A

    2002-04-01

    Examination of the five different water bodies in Dakahlia governorate, revealed four species of Lymnaea. These were L. natalensis (68.4%). L. truncatula (16%), L. stagnalis (12.2%) and L. columella (3.4%). Also, two species of Biomphalaria were recovered. These were B. alexandrina (54.7%) and B. glabrata (45.3%). Examination of all these snails showed natural infection with immature stages of Fasciola sp. in 5.5% of L. natalensis (= cailliaudi), 3.1% in L. truncatula and 0.67% in B. alexandrina. The importance of these snails in dissemination and spreading of fascioliasis was discussed.

  4. Ingestion of Fasciola gigantica metacercariae by the intermediate host snail, Lymnaea ollula, and infectivity of discharged metacercariae.

    PubMed

    Yoshihara, Shinobu; Ueno, Hakaru

    2004-09-01

    The rate of ingestion of Fasciola normal metacercariae (NMc) encysted on plants by Lymnaea ollula was examined, and the infectivity of the ingested metacercariae (IMc) in the feces of the host snail to mice was studied. As a result of ingestion by snails, the metacercarial outer cyst disappeared in about 50% of IMc in feces. There was no significant difference in the liver juvenile recovery at autopsy between mice inoculated with NMc and IMc kinds of metacercariae. Compared with NMc, the number of IMc could more easily be counted, because the separation of IMc from fecal contents under a microscope was not laborious.

  5. First report of Lymnaea columella Say, 1817 (Pulmonata: Lymnaeidae) naturally infected with Fasciola hepatica (Linnaeus,1758) (Trematoda: Digenea) in Argentina.

    PubMed

    Prepelitchi, Lucila; Kleiman, Florencia; Pietrokovsky, Silvia M; Moriena, Ricardo A; Racioppi, Oscar; Alvarez, José; Wisnivesky-Colli, Cristina

    2003-10-01

    We report the first evidence of natural infection of Lymnaea columella with Fasciola hepatica in Argentina. A sample of 601 snails was collected in May 2003 in northeastern Corrientes, a province bounded on the north by Paraguay, on the east by Brazil and on the southeast by Uruguay. Among 500 examined snails, 44 (8.8%) were exclusively infected with F. hepatica. Parasite identification was based on morphological features of cercariae from snails, and of eggs and adult flukes from Wistar rats. We discuss the events suggesting that an enzootic transmission cycle of F. hepatica has been recently established in northeastern Corrientes.

  6. Toxicity of Chlorophyllin against Lymnaea acuminata at Different Wavelengths of Visible Light

    PubMed Central

    Chaturvedi, Divya; Singh, Vinay Kumar

    2016-01-01

    Fasciolosis is a water and food-borne disease caused by the liver fluke Fasciola hepatica and Fasciola gigantica. This disease is widespread in different parts of the world. Lymnaeidae and Planorbidae snails are the intermediate hosts of these flukes. Snail population management is a good tool to control fasciolosis because gastropods represent the weakest link in the life-cycle of trematodes. Chlorophyll can be extracted from any green plant. Chlorophyllin was prepared from spinach in 100% ethanol by using different types of chemicals. The chlorophyll obtained from spinach was transformed into water-soluble chlorophyllin. In the present paper, toxicity of chlorophyllin against the snail Lymnaea acuminata was time and concentration dependent. The toxicity of extracted and pure chlorophyllin at continuous 4 h exposure of sunlight was highest with lethal concentration (LC50) of 331.01 mg/L and 2.60 mg/L, respectively, than discontinuous exposure of sunlight up to 8 h with LC50 of 357.04 mg/L and 4.94 mg/L, respectively. Toxicity of extracted chlorophyllin was noted in the presence of different monochromatic visible lights. The highest toxicity was noted in yellow light (96 h, LC50 392.77 mg/L) and the lowest in green light (96 h, LC50 833.02 mg/L). Chlorophyllin in combination with solar radiation or different wavelength of monochromatic visible lights may become a latent remedy against the snail L. acuminata. It was demonstrated that chlorophyllin was more toxic in sunlight. Chlorophyllin is ecologically safe and more economical than synthetic molluscicides which have the potential to control the incidence of fasciolosis in developing countries. PMID:27688849

  7. Differences in neuronal activity explain differences in memory forming abilities of different populations of Lymnaea stagnalis.

    PubMed

    Braun, Marvin H; Lukowiak, Kai; Karnik, Vikram; Lukowiak, Ken

    2012-01-01

    The ability to learn and form long-term memory (LTM) can enhance an animal's fitness, for example, by allowing them to remember predators, food sources or conspecific interactions. Here we use the pond snail, Lymnaea stagnalis, to assess whether variability between natural populations (i.e., strains) in memory forming capabilities correlates with electrophysiological properties at the level of a single neuron, RPeD1. RPeD1 is a necessary site of LTM formation of aerial respiratory behaviour following operant conditioning. We used strains from two small, separate permanent ponds (TC1 and TC2). A comparison of the two populations showed that the TC1 strain had enhanced memory forming capabilities. Further, the behavioural phenotype of enhanced memory strain was explained, in part, by differences in the electrophysiology of RPeD1. Compared to RPeD1 from the naive TC2 strain, RPeD1 from the TC1 strain has both a decreased resistance and decreased excitability. Moreover, 24h after a single 0.5h training session, those membrane properties, as well as the firing and bursting rate, decrease further in the TC1 strain but not in the TC2 strain. The initial differences in RPeD1 properties in the TC1 strain coupled with their ability to further change these properties with a single training session suggests that RPeD1 neurons from the TC1 strain are "primed" to rapidly form memory. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Neonicotinoid insecticides inhibit cholinergic neurotransmission in a molluscan (Lymnaea stagnalis) nervous system.

    PubMed

    Vehovszky, Á; Farkas, A; Ács, A; Stoliar, O; Székács, A; Mörtl, M; Győri, J

    2015-10-01

    Neonicotinoids are highly potent and selective systemic insecticides, but their widespread use also has a growing impact on non-target animals and contaminates the environment, including surface waters. We tested the neonicotinoid insecticides commercially available in Hungary (acetamiprid, Mospilan; imidacloprid, Kohinor; thiamethoxam, Actara; clothianidin, Apacs; thiacloprid, Calypso) on cholinergic synapses that exist between the VD4 and RPeD1 neurons in the central nervous system of the pond snail Lymnaea stagnalis. In the concentration range used (0.01-1 mg/ml), neither chemical acted as an acetylcholine (ACh) agonist; instead, both displayed antagonist activity, inhibiting the cholinergic excitatory components of the VD4-RPeD1 connection. Thiacloprid (0.01 mg/ml) blocked almost 90% of excitatory postsynaptic potentials (EPSPs), while the less effective thiamethoxam (0.1 mg/ml) reduced the synaptic responses by about 15%. The ACh-evoked membrane responses of the RPeD1 neuron were similarly inhibited by the neonicotinoids, confirming that the same ACh receptor (AChR) target was involved. We conclude that neonicotinoids act on nicotinergic acetylcholine receptors (nAChRs) in the snail CNS. This has been established previously in the insect CNS; however, our data indicate differences in the background mechanism or the nAChR binding site in the snail. Here, we provide the first results concerning neonicotinoid-related toxic effects on the neuronal connections in the molluscan nervous system. Aquatic animals, including molluscs, are at direct risk while facing contaminated surface waters, and snails may provide a suitable model for further studies of the behavioral/neuronal consequences of intoxication by neonicotinoids. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Silver nanoparticles alter learning and memory formation in an aquatic organism, Lymnaea stagnalis.

    PubMed

    Young, Austin; Protheroe, Amy; Lukowiak, Ken

    2017-06-01

    We tested the effect of silver nanoparticles (AgNPs) on the ability of the pond snail, Lymnaea stagnalis, to learn and form long-term memory (LTM) following operant conditioning of aerial respiration. We hypothesized that the AgNPs would act as a stressor and prevent learning and LTM formation. We tested snails exposed for either 72 h or only during training and testing for memory (i.e. 0.5 h) and found no difference between those treatments. We found that at a low concentration of AgNPs (5 μg/L) neither learning and nor memory formation were altered. When we increased the concentration of AgNPs (10 μg/L) we found that memory formation was enhanced. Finally, at a higher concentration (50 μg/L) memory formation was blocked. To determine if the disassociation of Ag(+) from the AgNPs caused the effects on memory we performed similar experiments with AgNO3 and found similar concentration-dependent results. Finally, we found that snails perceive the AgNPs differently from Ag+ as there was context specific memory. That is, snails trained in AgNPs did not show memory when tested in Ag(+) and vice-versa. We believe that changes in memory formation may be a more sensitive determination of AgNPs on aquatic organisms than the determination of a LC50. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  10. Evidence of trophic transfer of microcystins from the gastropod Lymnaea stagnalis to the fish Gasterosteus aculeatus.

    PubMed

    Lance, Emilie; Petit, Anais; Sanchez, Wilfried; Paty, Christelle; Gérard, Claudia; Bormans, Myriam

    2014-01-01

    According to our previous results the gastropod Lymnaea stagnalis exposed to MC-producing cyanobacteria accumulates microcystins (MCs) both as free and covalently bound forms in its tissues, therefore representing a potential risk of MC transfer through the food web. This study demonstrates in a laboratory experiment the transfer of free and bound MCs from L. stagnalis intoxicated by MC-producing Planktothrix agardhii ingestion to the fish Gasterosteus aculeatus. Fish were fed during five days with digestive glands of L. stagnalis containing various concentrations of free and bound MCs, then with toxin-free digestive glands during a 5-day depuration period. MC accumulation was measured in gastropod digestive gland and in various fish organs (liver, muscle, kidney, and gills). The impact on fish was evaluated through detoxification enzyme (glutathion-S-transferase, glutathion peroxydase and superoxyde dismutase) activities, hepatic histopathology, and modifications in gill ventilation, feeding and locomotion. G. aculeatus ingestion rate was similar with intoxicated and toxin-free diet. Fish accumulated MCs (up to 3.96±0.14μgg(-1)DW) in all organs and in decreasing order in liver, muscle, kidney and gills. Hepatic histopathology was moderate. Glutathion peroxydase was activated in gills during intoxication suggesting a slight reactive oxygen species production, but without any impact on gill ventilation. Intoxication via ingestion of MC-intoxicated snails impacted fish locomotion. Intoxicated fish remained significantly less mobile than controls during the intoxication period possibly due to a lower health condition, whereas they showed a greater mobility during the depuration period that might be related to an acute foraging for food. During depuration, MC elimination was total in gills and kidney, but partial in liver and muscle. Our results assess the MC transfer from gastropods to fish and the potential risk induced by bound MCs in the food web.

  11. Pronase acutely modifies high voltage-activated calcium currents and cell properties of Lymnaea neurons.

    PubMed

    Hermann, P M; Lukowiak, K; Wildering, W C; Bulloch, A G

    1997-12-01

    Pronase E ('pronase') is one of the proteolytic enzymes that are used in preparative procedures such as cell isolation and to soften the sheath of invertebrate ganglia. Although several effects of proteolytic enzymes on the physiology of non-neuronal tissues have been described, the effects of these enzymes on central neurons have received little attention. We examined the effects of bath-applied pronase on neurons in the Lymnaea central nervous system and in vitro. Pronase caused action potential broadening in neurons that exhibit a shoulder on the repolarization phase of their action potentials. This effect of pronase was accompanied by, although unrelated to, a depolarization and decrease in action potential interval. Some, but not all, effects of pronase in the central nervous system were reversible. For example, the decreases in membrane potential and action potential interval were both reversed after approximately 1 h of washing with saline. However, the effect of pronase on the action potential duration was not reversed after a period of 90 min. The modulation of action potential width prompted us to examine Ca2+ currents. Exposure to pronase resulted in an increase in both peak and late high voltage-activated Ca2+ currents in isolated neurons. Pronase neither changed the inactivation rate nor caused a shift in the current-voltage relationship of the current. The changes in action potential duration could be prevented by application of 0.1 mM Cd2+, indicating that the action potential broadening caused by pronase depends on Ca2+ influx. This is the first systematic study of the acute and direct actions of pronase on Ca2+ currents and cell properties both in the CNS and in vitro.

  12. Aluminum-dependent regulation of intracellular silicon in the aquatic invertebrate Lymnaea stagnalis

    PubMed Central

    Desouky, Mahmoud; Jugdaohsingh, Ravin; McCrohan, Catherine R.; White, Keith N.; Powell, Jonathan J.

    2002-01-01

    Silicon is essential for some plants, diatoms, and sponges but, in higher animals, its endogenous regulation has not been demonstrated. Silicate ions may be natural ligands for aluminum and here we show that, in the freshwater snail (Lymnaea stagnalis), intracellular silicon seems specifically up-regulated in response to sublethal aluminum exposure. X-ray microanalysis showed that exposure of snails to low levels of aluminum led to its accumulation in lysosomal granules, accompanied by marked up-regulation of silicon. Increased lysosomal levels of silicon were a specific response to aluminum because cadmium and zinc had no such effect. Furthermore, intra-lysosomal sulfur from metallothionein and other sulfur-containing ligands was increased after exposure to cadmium and zinc but not aluminum. To ensure that these findings indicated a specific in vivo response, and not ex vivo formation of hydroxy-aluminosilicates (HAS) from added aluminum (555 μg/liter) and water-borne silicon (43 μg/liter), two further studies were undertaken. In a ligand competition assay the lability of aluminum (527 μg/liter) was completely unaffected by the presence of silicon (46 μg/liter), suggesting the absence of HAS. In addition, exogenous silicon (6.5 mg/liter), added to the water column to promote formation of HAS, caused a decrease in lysosomal aluminum accumulation, showing that uptake of HAS would not explain the loading of aluminum into lysosomal granules. These findings, and arguments on the stability, lability, and kinetics of aluminum–silicate interactions, suggest that a silicon-specific mechanism exists for the in vivo detoxification of aluminum, which provides regulatory evidence of silicon in a multicellular organism. PMID:11891333

  13. Toxicity of Chlorophyllin against Lymnaea acuminata at Different Wavelengths of Visible Light.

    PubMed

    Chaturvedi, Divya; Singh, Vinay Kumar

    2016-08-01

    Fasciolosis is a water and food-borne disease caused by the liver fluke Fasciola hepatica and Fasciola gigantica. This disease is widespread in different parts of the world. Lymnaeidae and Planorbidae snails are the intermediate hosts of these flukes. Snail population management is a good tool to control fasciolosis because gastropods represent the weakest link in the life-cycle of trematodes. Chlorophyll can be extracted from any green plant. Chlorophyllin was prepared from spinach in 100% ethanol by using different types of chemicals. The chlorophyll obtained from spinach was transformed into water-soluble chlorophyllin. In the present paper, toxicity of chlorophyllin against the snail Lymnaea acuminata was time and concentration dependent. The toxicity of extracted and pure chlorophyllin at continuous 4 h exposure of sunlight was highest with lethal concentration (LC50) of 331.01 mg/L and 2.60 mg/L, respectively, than discontinuous exposure of sunlight up to 8 h with LC50 of 357.04 mg/L and 4.94 mg/L, respectively. Toxicity of extracted chlorophyllin was noted in the presence of different monochromatic visible lights. The highest toxicity was noted in yellow light (96 h, LC50 392.77 mg/L) and the lowest in green light (96 h, LC50 833.02 mg/L). Chlorophyllin in combination with solar radiation or different wavelength of monochromatic visible lights may become a latent remedy against the snail L. acuminata. It was demonstrated that chlorophyllin was more toxic in sunlight. Chlorophyllin is ecologically safe and more economical than synthetic molluscicides which have the potential to control the incidence of fasciolosis in developing countries.

  14. On the Ultrastructure and Function of Rhogocytes from the Pond Snail Lymnaea stagnalis

    PubMed Central

    Kokkinopoulou, Maria; Spiecker, Lisa; Messerschmidt, Claudia; Barbeck, Mike; Ghanaati, Shahram; Landfester, Katharina; Markl, Jürgen

    2015-01-01

    Rhogocytes, also termed “pore cells”, occur as solitary or clustered cells in the connective tissue of gastropod molluscs. Rhogocytes possess an enveloping lamina of extracellular matrix and enigmatic extracellular lacunae bridged by cytoplasmic bars that form 20 nm diaphragmatic slits likely to act as a molecular sieve. Recent papers highlight the embryogenesis and ultrastructure of these cells, and their role in heavy metal detoxification. Rhogocytes are the site of hemocyanin or hemoglobin biosynthesis in gastropods. Based on electron microscopy, we recently proposed a possible pathway of hemoglobin exocytosis through the slit apparatus, and provided molecular evidence of a common phylogenetic origin of molluscan rhogocytes, insect nephrocytes and vertebrate podocytes. However, the previously proposed secretion mode of the respiratory proteins into the hemolymph is still rather hypothetical, and the possible role of rhogocytes in detoxification requires additional data. Although our previous study on rhogocytes of the red-blooded (hemoglobin-containing) freshwater snail Biomphalaria glabrata provided much new information, a disadvantage was that the hemoglobin molecules were not unequivocally defined in the electron microscope. This made it difficult to trace the exocytosis pathway of this protein. Therefore, we have now performed a similar study on the rhogocytes of the blue-blooded (hemocyanin-containing) freshwater snail Lymnaea stagnalis. The intracellular hemocyanin could be identified in the electron microscope, either as individual molecules or as pseudo-crystalline arrays. Based on 3D-electron microscopy, and supplemented by in situ hybridization, immunocytochemistry and stress response experiments, we provide here additional details on the structure and hemocyanin biosynthesis of rhogocytes, and on their response in animals under cadmium and starvation stress. Moreover, we present an advanced model on the release of synthesized hemocyanin molecules

  15. Serotonergic and dopaminergic influence of the duration of embryogenesis and intracapsular locomotion of Lymnaea stagnalis L.

    PubMed

    Filla, Adrienn; Hiripi, L; Elekes, K

    2004-01-01

    The role of the dopaminergic and serotonergic system was studied during the embryonic development of the pond snail Lymnaea stagnalis, with special attention to the effect of dopamine and serotonin as well as their agonists and antagonists on the rotation of the veliger larvae, and to the effect of precursors and inhibitors of the synthetizing enzymes on the duration of the embryonic life. Serotonin, D-lysergic acid diethylamide and N,N-dimethyltryptamine increased at a concentration of 1 microM the rotation by 50%, 90% and 87% respectively, and among them D-Lysergic acid diethylamide was found to be the most potent agonist. Other serotonergic agonists and antagonists enhanced the frequency of the rotation (from 165% to 355%) at higher threshold concentrations in the following rank order: methysergid > tryptamine > 2,5-dimethoxy-4-iodoamphetamine > 5-carboxyamidotryptamine > bromo-lysergic acid diethylamide > 7-methyltryptamine. Application of 1-(2-methoxyphenyl) piperazine decreased the rotation by 76%. The reuptake inhibitor desipramine completely blocked the rotation and killed the embryos. Dopaminergic agonists accelerated the rotation by 62% to 233%, and their effect was ranged as follows: dopamine > apomorphine > m-tyramine approximately equal to p-tyramine. Chlorpromazine at 100 microM concentration killed the embryos. At a concentration of 100 microg/ml, tyrosine, the precursor of DA, slowed down the embryonic development by increasing the duration of the embryonic life from 8 to 10 days. Decarboxylase inhibitors, alpha-methyl-3,4-dihydroxyphenyl-alanine (25 microg/ml) and m-hydroxybenzylhydrazin (5 microg/ml), killed 50% of the embryos, meanwhile the rest hatched ten days later, compared to the control animals. The development was partially blocked by the serotonin precusor L-tryptophane (50 microg/ml). Trytophan hydroxylase blocker, p-chlorphenylalanine (50 microg/ml) resulted in a distortion of the body pattern of the embryos, and prevented the hatching

  16. Enhanced memory persistence is blocked by a DNA methyltransferase inhibitor in the snail Lymnaea stagnalis.

    PubMed

    Lukowiak, Ken; Heckler, Benjamin; Bennett, Thomas E; Schriner, Ellen K; Wyrick, Kathryn; Jewett, Cynthia; Todd, Ryan P; Sorg, Barbara A

    2014-08-15

    Lymnaea stagnalis provides an excellent model system for studying memory because these snails have a well-described set of neurons, a single one of which controls expression of long-term memory of operantly conditioned respiratory behavior. We have shown that several different manipulations, including pre-training exposure to serotonin (5-HT) or methamphetamine, submersion of snails after training to prevent memory interference, and exposure to effluent from predatory crayfish (CE), enhance memory persistence. Changes in DNA methylation underlie formation of strong memories in mammals and 5-HT-enhanced long-term facilitation in Aplysia. Here we determined the impact of the DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5-AZA; 87 μmol l(-1)), on enhanced memory persistence by all four manipulations. We found that 5-HT (100 μmol l(-1)) enhanced memory persistence, which was blocked by 5-AZA pretreatment. Snails pre-exposed to 3.3 μmol l(-1) Meth 4 h prior to training demonstrated memory 72 h later, which was not present in controls. This memory-enhancing effect was blocked by pre-treatment with 87 μmol l(-1) 5-AZA. Similarly, submersion to prevent interference learning as well as training in CE produced memory that was not present in controls, and these effects were blocked by pre-treatment with 87 μmol l(-1) 5-AZA. In contrast, 5-AZA injection did not alter expression of normal (non-enhanced) memory, suggesting that these four stimuli enhance memory persistence by increasing DNA methyltransferase activity, which, in turn, increases expression of memory-enhancing genes and/or inhibits memory suppressor genes. These studies lay important groundwork for delineating gene methylation changes that are common to persistent memory produced by different stimuli.

  17. An ancient process in a modern mollusc: early development of the shell in Lymnaea stagnalis

    PubMed Central

    2013-01-01

    Background The morphological variety displayed by the molluscan shell underlies much of the evolutionary success of this phylum. However, the broad diversity of shell forms, sizes, ornamentations and functions contrasts with a deep conservation of early cell movements associated with the initiation of shell construction. This process begins during early embryogenesis with a thickening of an ectodermal, ‘dorsal’ (opposite the blastopore) population of cells, which then invaginates into the blastocoel to form the shell gland. The shell gland evaginates to form the shell field, which then expands and further differentiates to eventually become the adult shell-secreting organ commonly known as the mantle. Despite the deep conservation of the early shell forming developmental program across molluscan classes, little is known about the fine-scale cellular or molecular processes that underlie molluscan shell development. Results Using modern imaging techniques we provide here a description of the morphogenesis of a gastropod shell gland and shell field using the pulmonate gastropod Lymnaea stagnalis as a model. We find supporting evidence for a hypothesis of molluscan shell gland specification proposed over 60 years ago, and present histochemical assays that can be used to identify a variety of larval shell stages and distinct cell populations in whole mounts. Conclusions By providing a detailed spatial and temporal map of cell movements and differentiation events during early shell development in L. stagnalis we have established a platform for future work aimed at elucidation of the molecular mechanisms and regulatory networks that underlie the evo-devo of the molluscan shell. PMID:23845038

  18. Lymnaea schirazensis, an overlooked snail distorting fascioliasis data: genotype, phenotype, ecology, worldwide spread, susceptibility, applicability.

    PubMed

    Bargues, María Dolores; Artigas, Patricio; Khoubbane, Messaoud; Flores, Rosmary; Glöer, Peter; Rojas-García, Raúl; Ashrafi, Keyhan; Falkner, Gerhard; Mas-Coma, Santiago

    2011-01-01

    Lymnaeid snails transmit medical and veterinary important trematodiases, mainly fascioliasis. Vector specificity of fasciolid parasites defines disease distribution and characteristics. Different lymnaeid species appear linked to different transmission and epidemiological patterns. Pronounced susceptibility differences to absolute resistance have been described among lymnaeid populations. When assessing disease characteristics in different endemic areas, unexpected results were obtained in studies on lymnaeid susceptibility to Fasciola. We undertook studies to understand this disease transmission heterogeneity. A ten-year study in Iran, Egypt, Spain, the Dominican Republic, Mexico, Venezuela, Ecuador and Peru, demonstrated that such heterogeneity is not due to susceptibility differences, but to a hitherto overlooked cryptic species, Lymnaea schirazensis, confused with the main vector Galba truncatula and/or other Galba/Fossaria vectors. Nuclear rDNA and mtDNA sequences and phylogenetic reconstruction highlighted an old evolutionary divergence from other Galba/Fossaria species, and a low intraspecific variability suggesting a recent spread from one geographical source. Morphometry, anatomy and egg cluster analyses allowed for phenotypic differentiation. Selfing, egg laying, and habitat characteristics indicated a migration capacity by passive transport. Studies showed that it is not a vector species (n = 8572 field collected, 20 populations): snail finding and penetration by F. hepatica miracidium occur but never lead to cercarial production (n = 338 experimentally infected). This species has been distorting fasciolid specificity/susceptibility and fascioliasis geographical distribution data. Hence, a large body of literature on G. truncatula should be revised. Its existence has henceforth to be considered in research. Genetic data on livestock, archeology and history along the 10,000-year post-domestication period explain its wide spread from the Neolithic

  19. Tertiary combination of freeze-dried urine of Indian breeds of cow with plant products against snail Lymnaea acuminata.

    PubMed

    Kumar, Shiv; Singh, D K; Singh, Vinay Kumar

    2012-10-15

    Snail Lymnaea acuminata is the intermediate host of liver fluke Fasciola gigantica, which cause endemic fasciolosis among cattle population of eastern Uttar Pradesh. Control of snail population by molluscicides is one of the effective methods to control fasciolosis. In the present study molluscicidal activity of tertiary combination of freeze-dried urine of different Indian breeds of cow Sahiwal, Geer and Tharparkar with Annona squamosa seed powder, Ferula asafoetida root latex, Azadirachta indica oil and Camellia sinensis leaves have been tested against Lymnaea acuminata. It was noted that the toxicity of tertiary combination (1:1:5) of cow urine kept for 15 days in sunlight or laboratory condition with different plant products were highly toxic against snail L. acuminata. 96 h LC50 of tertiary combinations with Sahiwal urine kept for 15 days in sunlight with A. squamosa, F. asafoetida, A. indica oil and C. sinensis were 35.47 mg L(-1), 37.13 mg L(-1), 33.66 mg L(-1), respectively higher than the Geer and Tharparkar. The toxicity of Sahiwal urine kept for 15 days in laboratory condition with A. squamosa and C. sinensis (96 h LC50 28.28 mg L(-1)) was more potent than the all other combinations. Cow urine in combination with plant product can be used for effective control of snail.

  20. Pituitary adenylate cyclase activating polypeptide (PACAP) and its receptors are present and biochemically active in the central nervous system of the pond snail Lymnaea stagnalis.

    PubMed

    Pirger, Zsolt; Laszlo, Zita; Hiripi, Laszlo; Hernadi, Laszlo; Toth, Gabor; Lubics, Andrea; Reglodi, Dora; Kemenes, Gyorgy; Mark, Laszlo

    2010-11-01

    PACAP is a highly conserved adenylate cyclase (AC) activating polypeptide, which, along with its receptors (PAC1-R, VPAC1, and VPAC2), is expressed in both vertebrate and invertebrate nervous systems. In vertebrates, PACAP has been shown to be involved in associative learning, but it is not known if it plays a similar role in invertebrates. To prepare the way for a detailed investigation into the possible role of PACAP and its receptors in a suitable invertebrate model of learning and memory, here, we undertook a study of their expression and biochemical role in the central nervous system of the pond snail Lymnaea stagnalis. Lymnaea is one of the best established invertebrate model systems to study the molecular mechanisms of learning and memory, including the role of cyclic AMP-activated signaling mechanisms, which crucially depend on the learning-induced activation of AC. However, there was no information available on the expression of PACAP and its receptors in sensory structures and central ganglia of the Lymnaea nervous system known to be involved in associative learning or whether or not PACAP can actually activate AC in these ganglia. Here, using matrix-assisted laser desorption ionization time of flight (MALDI-TOF) and immunohistochemistry, we established the presence of PACAP-like peptides in the cerebral ganglia and the lip region of Lymnaea. The MALDI-TOF data indicated an identity with mammalian PACAP-27 and the presence of a squid-like PACAP-38 highly homologous to vertebrate PACAP-38. We also showed that PACAP, VIP, and maxadilan stimulated the synthesis of cAMP in Lymnaea cerebral ganglion homogenates and that this effect was blocked by the appropriate general and selective PACAP receptor antagonists.

  1. Investigations into the mechanism of lead toxicity to the freshwater pulmonate snail, Lymnaea stagnalis.

    PubMed

    Brix, Kevin V; Esbaugh, Andrew J; Munley, Kathleen M; Grosell, Martin

    2012-01-15

    The freshwater pulmonate snail, Lymnaea stagnalis, is the most sensitive aquatic organism tested to date for Pb with an estimated EC20 for juvenile snail growth of 3 μg l⁻¹. A previous study supported the hypothesis that this hypersensitivity to Pb was due to an extremely high Ca²⁺ uptake rate needed to support shell formation. The current study sought to build upon this working hypothesis and develop a mechanistic predictive model for inhibition of snail growth as a function of Pb exposure. Initial experiments confirmed previous predictions that juvenile snails have net Ca²⁺ uptake rates of 7000-8000 nmol g⁻¹ h⁻¹, approximately 100-fold higher than observed in a typical freshwater fish. However, an initial time course study revealed that the onset of growth inhibition occurs at least 4d prior to inhibition of net Ca²⁺ flux in Pb-exposed snails indicating the latter is not the primary mechanism of action. Qualitative observations during this experiment indicated snail feeding was inhibited in a dose-dependent manner. A subsequent experiment demonstrated that when food is withheld from snails for even 24 h, net Ca²⁺ uptake is significantly (∼50%) reduced. A second time course study demonstrated quantitatively that snail feeding is inhibited by Pb exposure by up to 98% at relatively high Pb concentrations (57 μg l⁻¹) but no inhibition was observed at ≤ 10 μg l⁻¹ Pb indicating feeding inhibition is not causing observed growth effects at concentrations approximating the EC20 of 3 μg l⁻¹ Pb. A final experiment testing whether Pb-induced growth effects are related to inhibition of carbonic anhydrase activity in the snail mantle also failed to demonstrate an effect. We conclude that while both feeding and net Ca²⁺ uptake in snails are affected by Pb exposure, they appear to be secondary effects. The primary mechanism of action explaining L. stagnalis hypersensitivity to Pb remains to be identified.

  2. Lymnaea schirazensis, an Overlooked Snail Distorting Fascioliasis Data: Genotype, Phenotype, Ecology, Worldwide Spread, Susceptibility, Applicability

    PubMed Central

    Bargues, María Dolores; Artigas, Patricio; Khoubbane, Messaoud; Flores, Rosmary; Glöer, Peter; Rojas-García, Raúl; Ashrafi, Keyhan; Falkner, Gerhard; Mas-Coma, Santiago

    2011-01-01

    Background Lymnaeid snails transmit medical and veterinary important trematodiases, mainly fascioliasis. Vector specificity of fasciolid parasites defines disease distribution and characteristics. Different lymnaeid species appear linked to different transmission and epidemiological patterns. Pronounced susceptibility differences to absolute resistance have been described among lymnaeid populations. When assessing disease characteristics in different endemic areas, unexpected results were obtained in studies on lymnaeid susceptibility to Fasciola. We undertook studies to understand this disease transmission heterogeneity. Methodology/Principal Findings A ten-year study in Iran, Egypt, Spain, the Dominican Republic, Mexico, Venezuela, Ecuador and Peru, demonstrated that such heterogeneity is not due to susceptibility differences, but to a hitherto overlooked cryptic species, Lymnaea schirazensis, confused with the main vector Galba truncatula and/or other Galba/Fossaria vectors. Nuclear rDNA and mtDNA sequences and phylogenetic reconstruction highlighted an old evolutionary divergence from other Galba/Fossaria species, and a low intraspecific variability suggesting a recent spread from one geographical source. Morphometry, anatomy and egg cluster analyses allowed for phenotypic differentiation. Selfing, egg laying, and habitat characteristics indicated a migration capacity by passive transport. Studies showed that it is not a vector species (n = 8572 field collected, 20 populations): snail finding and penetration by F. hepatica miracidium occur but never lead to cercarial production (n = 338 experimentally infected). Conclusions/Significance This species has been distorting fasciolid specificity/susceptibility and fascioliasis geographical distribution data. Hence, a large body of literature on G. truncatula should be revised. Its existence has henceforth to be considered in research. Genetic data on livestock, archeology and history along the 10,000-year

  3. Phyto-adaptogens protect against environmental stress-induced death of embryos from the freshwater snail Lymnaea stagnalis.

    PubMed

    Boon-Niermeijer, E K; van den Berg, A; Wikman, G; Wiegant, F A

    2000-10-01

    The main purpose of the studies presented in this paper is twofold: 1) to evaluate whether phyto-adaptogens (Acanthopanax senticosus and Rhodiola rosea) are able to exert a protective action against stress-induced death of embryos of the pond snail Lymnaea stagnalis; and 2) whether a possible protective action by phyto-adaptogens can be explained by the induction of heat shock proteins. Enhancement in resistance by phyto-adaptogens was studied by applying plant extracts for a period of 20 hours to 3-day old larvae of the pond snail Lymnaea stagnalis. Subsequently they were exposed to a high and toxic dose of different environmental stressors. The following stress conditions were selected: a physical stress condition (heat shock: 43 degrees C for 4 minutes), an oxidative stress condition (superoxide radicals induced by menadione (600 microM for 2 hours)) and heavy metal-induced stress (copper (150 microM for 1 hour) or cadmium (20 microM during 1 hour)). Both Acanthopanax and Rhodiola exert a strong protective action against a lethal heat shock. These adaptogens also significantly protect against the negative effect of superoxide radicals as induced by menadione. With respect to the protective action against exposure to heavy metals a small but significant protection was observed against intoxication with copper or cadmium by the phyto-adaptogens. In summary, there appears to be a difference in efficiency in enhancing resistance to the various stress conditions used (heat shock>menadione>copper>cadmium). Based on the results presented in this paper, we can conclude that phyto-adaptogens are able to enhance the resistance against the different stress conditions tested in developing individuals of Lymnaea. Although the degree to which resistance is enhanced appears to depend on the type of stressor applied, our results confirm the definition of phyto-adaptogens as being universal enhancers of non-specific resistance against different kinds of stress conditions. With

  4. Binary Combination of Carica papaya, Areca catechu and Myristica fragrans with Piperonyl Butoxide / MGK-264 against Freshwater Snail Lymnaea acuminata

    PubMed Central

    Hanif, Farhat; Singh, Dinesh Kumar

    2013-01-01

    Piperonyl butoxide (PB) and MGK-264 were used to enhance the toxicity of the active components papain, arecoline and myristicin from the plants Carica papaya, Areca catechu and Myristica fragrans, respectively, against the vector snail Lymnaea acuminata. A time- and dose-dependent relationship was observed for the toxicity of these combinations. The toxic effects of these plant-derived molluscicides in combination with the synergists PB and MGK-264 were several times higher than the effect of the individual treatments. The highest degree of synergism was observed when MGK-264 was used in combination with C. papaya latex (10.47-fold increase) and PB was used with papain (8.35-fold increase). PMID:24575245

  5. [THE EMISSION OF PLAGIORCHIS MULTIGLANDULARIS CERCARIAE FROM NATURALLY INFECTED SNAILS LYMNAEA STAGNALIS IN CHANY LAKE, SOUTH OF WEST SIBERIA].

    PubMed

    Rastyazhenko, N M; Vodyanitskaya, S N; Yurlova, N I

    2015-01-01

    The daily cercarial output of freshwater trematode Plagiorchis multiglandularis from naturally infected snail Lymnaea stagnalis were studied. The snails were collected in the Chany Lake (South of West Siberia). The daily cercarial output from the snail of different size was determined. The average daily cercarial output ranged from 4641 ± 1829 at the snail with shell length 29 mm to 14022 ± 5198 at the snail with shell length 44 mm. The positive correlation between the average daily cercarial output and the shell of snail host was found (p ≤ 0.001). The maximum of P. multiglandularis cercariae release from the snail during daytime, that coincided with period of activity of the second intermediate hosts. Temperature-mediated increase in cercarial output of P. multiglandularis in temperature range 23-24.5 degrees C was found. The cercarial output was inhibited over the temperature optimum.

  6. Effect of DDT and MCPA (4-chloro-2-methylphenoxyacetic acid) on reproduction of the pond snail, Lymnaea stagnalis L

    SciTech Connect

    Woin, P.; Broenmark, C. )

    1992-01-01

    Reproduction is the single most important function in the life cycle of an organism. Successful reproduction determines fitness of organisms. The inability of an organism to complete any one stage of the reproductive process severely reduces its lifetime reproductive success. Disruptions in the reproduction will ultimately affect the abundance and distribution of the species. Therefore, laboratory tests of long-term impact of sublethal pollutant concentrations on organisms preferably is done on the reproductive success. Pollutants of diverse structure may affect the reproductive system which is sensitive to toxic agents. Certain pollutants, notably the organochlorine compounds, have been shown to affect the male and female reproductive systems. The authors have studied the effect of sublethal concentrations of DDT and the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) on the reproductive output of the pulmonate snail Lymnaea stagnalis under a 2-mon exposure period.

  7. Structure-dependent effects of amyloid-β on long-term memory in Lymnaea stagnalis.

    PubMed

    Ford, Lenzie; Crossley, Michael; Vadukul, Devkee M; Kemenes, György; Serpell, Louise C

    2017-05-01

    Amyloid-β (Aβ) peptides are implicated in the causation of memory loss, neuronal impairment, and neurodegeneration in Alzheimer's disease. Our recent work revealed that Aβ 1-42 and Aβ 25-35 inhibit long-term memory (LTM) recall in Lymnaea stagnalis (pond snail) in the absence of cell death. Here, we report the characterization of the active species prepared under different conditions, describe which Aβ species is present in brain tissue during the behavioral recall time point and relate the sequence and structure of the oligomeric species to the resulting neuronal properties and effect on LTM. Our results suggest that oligomers are the key toxic Aβ1-42 structures, which likely affect LTM through synaptic plasticity pathways, and that Aβ 1-42 and Aβ 25-35 cannot be used as interchangeable peptides. © 2017 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

  8. Binary Combination of Carica papaya, Areca catechu and Myristica fragrans with Piperonyl Butoxide / MGK-264 against Freshwater Snail Lymnaea acuminata.

    PubMed

    Hanif, Farhat; Singh, Dinesh Kumar

    2013-12-01

    Piperonyl butoxide (PB) and MGK-264 were used to enhance the toxicity of the active components papain, arecoline and myristicin from the plants Carica papaya, Areca catechu and Myristica fragrans, respectively, against the vector snail Lymnaea acuminata. A time- and dose-dependent relationship was observed for the toxicity of these combinations. The toxic effects of these plant-derived molluscicides in combination with the synergists PB and MGK-264 were several times higher than the effect of the individual treatments. The highest degree of synergism was observed when MGK-264 was used in combination with C. papaya latex (10.47-fold increase) and PB was used with papain (8.35-fold increase).

  9. Effects of DDT and permethrin on neurite growth in cultured neurons of chick embryo brain and Lymnaea stagnalis.

    PubMed

    Ferguson, C A; Audesirk, G

    1990-01-01

    The pesticides permethrin and 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT), dissolved in either ethanol (EtOH) or dimethylsulphoxide (DMSO), were studied to determine their effect on neurite growth from cultured neurons of Lymnaea stagnalis and embryonic chicks. Both of these toxins decreased the percentage of neurons growing neurites, mean neurite length, and number of neurites/cell in a dose-dependent manner. DMSO increased the toxicity of permethrin and DDT in L. stagnalis neurons. EtOH was not used as a solvent with the embryonic chick cultures. Pre-existing neurites of L. stagnalis neurons exposed to permethrin regressed in a dose- and time-dependent manner. These two toxins may affect neurite outgrowth through interference with intracellular calcium regulation.

  10. Comparative shell morphology of Lymnaea (Bullastra) cumingiana (Pulmonata: Lymnaeidae) and related taxa in the Indo-Pacific region.

    PubMed

    Monzon, R B; Kitikoon, V; Thammapalerd, N; Temcharoen, P; Sornmani, S; Viyanant, V

    1993-09-01

    Comparative shell morphology using both quantitative and qualitative parameters was employed to investigate the taxonomic relationship between the endemic Philippine species, Lymnaea (Bullastra) cumingiana and five other lymnaeid "species" in the Indo-Pacific region, namely: L. (Radix) quadrasi (Philippines). L. (Radix) rubiginosa (Indonesia), L. (Radix) rubiginosa (Thailand), L. (Radix) viridis (Guam) and L. (Radix) viridis (Hong Kong). Fifty randomly chosen adult specimens of each species were studied and compared, although only field-collected specimens were studied for the first four groups and laboratory-raised specimens for the last two group. Results strongly suggested that L. cumingiana is a distinct species among the rest. L. quadrasi, L. rubiginosa (Indonesia) and L. rubiginosa (Thailand) exhibited great affinity towards each other. Likewise, the two geographical isolates of L. viridis were practically identical to each other except for some minor size differences.

  11. Effect of non target snails on some biological of Lymnaea natalensis snails and their infection to Fasciola gigantica.

    PubMed

    Bakry, Fayez A; Hamdi, Salwa A H

    2006-12-01

    The influence of non-target freshwater snails (Melanoides tuberculata and Planorbis planorbis) on the capacity of Fasciola egg production F. gigantica miracidia to infect Lymnaea natalensis and their effect on mortality and growth rates showed that the snails exhibited a competitive ability against L. natalensis. The mortality rate existed in mixed cultures with snails was greatly increased, and increased with increase of snails number. The egg production and growth rate were negatively affected by the presence of M. tuberculata and P. planorbis which was more pronounced when snails were at higher ratio lL: 10D. Also, the snails showed significant degree of reduction in infection rate of L. natalensis with F. gigantica miracidia.

  12. Sympatric and allopatric combinations of Lymnaea columella and Fasciola hepatica from southern and south-eastern Brazil.

    PubMed

    Coelho, L H L; Lima, W S; Guimaraes, M P

    2009-09-01

    Experimental infections of Lymnaea columella with Fasciola hepatica were carried out to test the effect of sympatric and allopatric combinations between parasite and host, by using snails and flukes from southern and south-eastern Brazil. Four groups of 50 snails were infected with four miracidia per snail: two groups in sympatric and two groups in allopatric combinations. Sympatric combinations between parasite and host were more efficient than allopatric ones when snails from Itajubá were used, but the opposite was observed in infections involving snails from Pelotas. The sympatric association between L. columella and F. hepatica from Itajubá was significantly higher than in the other combinations. We concluded that the host-parasite relationship between L. columnella and F. hepatica may vary according to the geographical origin of the snails and flukes involved.

  13. Population dynamics of Lymnaea columella and its natural infection by Fasciola hepatica in the State of Minas Gerais, Brazil.

    PubMed

    Coelho, L H L; Lima, W S

    2003-03-01

    Studies on the population dynamics and natural infection of Lymnaea columella by Fasciola hepatica were carried out from September 1999 to December 2000 in a low-lying area near Itajubá in the Brazilian State of Minas Gerais. A total of 626 snails were collected monthly at nine different sites, counted, and dissected to search for larvae of F. hepatica. The highest populations of L. columella were reached in October of 1999 and August of 2000, and the highest natural infection rates of snails by F. hepatica were reached in September 1999 (5.2%) and July 2000 (3.9%). The removal by farmers of aquatic plants from the drainage furrows caused a drastic reduction in this snail population.

  14. Genetic variability of Brazilian populations of Lymnaea columella (Gastropoda: Lymnaeidae), an intermediate host of Fasciola hepatica (Trematoda: Digenea).

    PubMed

    Cardoso, Paula Cristina Marques; Caldeira, Roberta Lima; Lovato, Maria Bernadete; Coelho, Paulo Marcos Zech; Berne, Maria Elisabeth Aires; Müller, Gertrud; Carvalho, Omar dos Santos

    2006-03-01

    In Brazil, Lymnaea columella is the most important intermediate host of Fasciola hepatica, the etiological agent of fasciolosis, which is a parasitic disease of veterinarian and human importance. Random amplified polymorphic DNA (RAPD) was used to investigate the genetic variability within and among nine Brazilian populations of L. columella comprising 205 individuals. A number of four primers were used for analysis of molecular variance (AMOVA). Out of 83 RAPD markers, 63 (76%) were polymorphic and revealed 119 unique RAPD profiles. The levels of genetic variability found in the populations were low and most of the genetic variation was interpopulational (81.6%) when compared to intrapopulational variability (18.4%). These results are in accordance with the dynamics and distribution of the populations analyzed.

  15. Kinetics of enzyme inhibition by active molluscicidal agents ferulic acid, umbelliferone, eugenol and limonene in the nervous tissue of snail Lymnaea acuminata.

    PubMed

    Kumar, Pradeep; Singh, V K; Singh, D K

    2009-02-01

    Ferulic acid, umbelliferone (Ferula asafoetida), eugenol (Syzygium aromaticum) and limonene (Carum carvi) are active molluscicidal components that inhibited the activity of alkaline phosphatase and acetylcholinesterase in in vivo and in vitro exposure of Lymnaea acuminata. It was observed that ferulic acid, umbelliferone and eugenol are competitive and limonene is a competitive-non-competitive inhibitor of alkaline phosphatase. Ferulic acid and umbelliferone are competitive, whereas eugenol and limonene are competitive-non-competitive and uncompetitive inhibitors of acetylcholinesterase, respectively.

  16. Effects of in vitro lead exposure on voltage-sensitive calcium channels differ among cell types in central neurons of Lymnaea stagnalis.

    PubMed

    Audesirk, G; Audesirk, T

    1989-01-01

    The effects of acute in vitro lead exposure on slowly inactivating voltage-sensitive calcium channels in central neurons of the freshwater pond snail Lymnaea stagnalis were studied under voltage clamp. Three physiologically distinct cell types were used: two subsets of the B cell cluster (Bpos and Bneg) and the pedal giant neuron (RPeD1). In Bpos neurons, 5 nM free Pb2+ irreversibly inhibited current flow through calcium channels by 38 +/- 10%. In Bneg neurons, 5 nM free Pb2+ slightly inhibited inward currents (12 +/- 6%) and may have shifted their voltage dependence to more depolarized voltages. The inhibition and voltage shift were irreversible. In RPeD1 neurons, Pb2+ caused a small, statistically insignificant inhibition of inward current (5 nM free Pb2+; 18 +/- 19%; 30 nM free Pb2+: 31 +/- 23%). The effects of Pb2+ were fully reversible. These data indicate that (1) voltage-sensitive calcium channels in Lymnaea neurons are inhibited by nanomolar concentrations of free Pb2+; (2) there are multiple types of calcium channels in Lymnaea neurons; and (3) the effects of in vitro lead exposure differ qualitatively among channel types.

  17. Feeding of Bait to Snail Lymnaea acuminata and Their Effect on Certain Enzyme in the Nervous Tissue

    PubMed Central

    Kumar, Pradeep; Singh, V. K.; Singh, D. K.

    2012-01-01

    Fascioliasis, a snail-borne parasitic zoonosis, has been recognized for a long time because of its major veterinary and human impact. Different Bait formulations were fed to the snail Lymnaea acuminata in clear glass aquaria having diameter of 30 cm. Snail attractant containing bait formulations was prepared from different binary combination (1 : 1 ratio) of carbohydrates (glucose, starch 10 mM) and amino acid (methionine, histidine 10 mM) in 100 ml of 2% agar solution + sublethal (20% and 60% of 24 h and 96 h LC50) doses of different molluscicides (eugenol, ferulic acid, umbelliferone, and limonene). Snails fed on bait containing sub-lethal concentration of different molluscicides and the snail attractant, causing a significant inhibition in alkaline phosphatase (ALP) and acetylcholinesterase (AChE) activity in the nervous tissue of the vector snail L. acuminata. Maximum inhibition in ALP (20% of control) and AChE (49.49% of control) activity was observed in the nervous tissue of the L. acuminata exposed to 60% of 96 h LC50 of eugenol in the bait pellets containing starch + histidine, starch + methionine, respectively. PMID:25969756

  18. Characterization of the molluscicidal activity of Bauhinia variegata and Mimusops elengi plant extracts against the fasciola vector Lymnaea acuminata.

    PubMed

    Singh, Kanchan Lata; Singh, D K; Singh, Vinay Kumar

    2012-01-01

    The molluscicidal activity of Bauhinia variegata leaf and Mimusops elengi bark was studied against vector snail Lymnaea acuminata. The toxicity of both plants was time and concentration-dependent. Among organic extracts, ethanol extracts of both plants were more toxic. Toxicity of B. variegata leaf ethanolic extract (96h LC50- 14.4 mg/L) was more pronounced than M. elengi bark ethanolic extract (96h LC50-15.0 mg/L). The 24h LC50 of column purified fraction of B. variegata and M. elengi bark were 20.3 mg/L and 18.3 mg/L, respectively. Saponin and quercetin were characterized and identified as active molluscicidal component. Co-migration of saponin (Rf 0.48) and quercetin (Rf 0.52) with column purified bark of M. elengi and leaf of B. variegata on thin layer chromatography demonstrate same Rf value i.e. 0.48 and 0.52, respectively. The present study clearly indicates the possibility of using M. elengi and/or B. variegata as potent molluscicide.

  19. Small-scale to large-scale and back: larval trematodes in Lymnaea stagnalis and Planorbarius corneus in Central Europe.

    PubMed

    Brown, Rebecca; Soldánová, Miroslava; Barrett, John; Kostadinova, Aneta

    2011-01-01

    We examined the small-scale temporal and spatial variability in composition and structure of larval trematode communities in Lymnaea stagnalis and Planorbarius corneus in two fish ponds in the Czech Republic and compared the patterns of richness and similarity to continental and regional trematode faunas of these hosts. The levels of parasitism in the populations of both hosts were high, the former parasitized predominantly by allogenic species maturing in a wide range of birds and the latter infected by relatively more species completing their life cycles in micromammals. Communities in both hosts exhibited a congruent pattern of seasonal change in overall infection rates and community composition with lower levels of infection in spring. Both temporal and spatial variation was closely related to the structure of snail populations, and no significant differentiation of community composition with respect to pond was observed. Comparisons with large-scale inventories revealed overall congruent patterns of decreased richness and similarity and increased variability at the smaller scales in both host-parasite systems. The relative compositional homogeneity of larval communities in both snail hosts irrespective of scale suggests that historical data at small to medium regional scales may provide useful estimates of past richness and composition of larval trematode communities in these snail hosts.

  20. Metabolomics to Explore Imidacloprid-Induced Toxicity in the Central Nervous System of the Freshwater Snail Lymnaea stagnalis.

    PubMed

    Tufi, Sara; Stel, Jente M; de Boer, Jacob; Lamoree, Marja H; Leonards, Pim E G

    2015-12-15

    Modern toxicology is seeking new testing methods to better understand toxicological effects. One of the most concerning chemicals is the neonicotinoid pesticide imidacloprid. Although imidacloprid is designed to target insects, recent studies have shown adverse effects on nontarget species. Metabolomics was applied to investigate imidacloprid-induced sublethal toxicity in the central nervous system of the freshwater snail Lymnaea stagnalis. The snails (n = 10 snails) were exposed for 10 days to increasing imidacloprid concentrations (0.1, 1, 10, and 100 μg/L). The comparison between control and exposure groups highlighted the involvement and perturbation of many biological pathways. The levels of several metabolites belonging to different metabolite classes were significantly changed by imidacloprid exposure. A change in the amino acids and nucleotide metabolites like tryptophan, proline, phenylalanine, uridine, and guanosine was found. Many fatty acids were down-regulated, and the levels of the polyamines, spermidine and putrescine, were found to be increased which is an indication of neuron cell injury. A turnover increase between choline and acetylcholine led us to hypothesize an increase in cholinergic gene expression to overcome imidacloprid binding to the nicotinic acetylcholine receptors. Metabolomics revealed imidacloprid induced metabolic changes at low and environmentally relevant concentration in a nontarget species and generated a novel mechanistic hypothesis.

  1. Does water chemistry affect the dietary uptake and toxicity of silver nanoparticles by the freshwater snail Lymnaea stagnalis?

    USGS Publications Warehouse

    López-Serrano Oliver, Ana; Croteau, Marie-Noële; Stoiber, Tasha L.; Tejamaya, Mila; Römer, Isabella; Lead, Jamie R.; Luoma, Samuel N.

    2014-01-01

    Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important.

  2. Modelling effects of diquat under realistic exposure patterns in genetically differentiated populations of the gastropod Lymnaea stagnalis

    PubMed Central

    Ducrot, Virginie; Péry, Alexandre R. R.; Lagadic, Laurent

    2010-01-01

    Pesticide use leads to complex exposure and response patterns in non-target aquatic species, so that the analysis of data from standard toxicity tests may result in unrealistic risk forecasts. Developing models that are able to capture such complexity from toxicity test data is thus a crucial issue for pesticide risk assessment. In this study, freshwater snails from two genetically differentiated populations of Lymnaea stagnalis were exposed to repeated acute applications of environmentally realistic concentrations of the herbicide diquat, from the embryo to the adult stage. Hatching rate, embryonic development duration, juvenile mortality, feeding rate and age at first spawning were investigated during both exposure and recovery periods. Effects of diquat on mortality were analysed using a threshold hazard model accounting for time-varying herbicide concentrations. All endpoints were significantly impaired at diquat environmental concentrations in both populations. Snail evolutionary history had no significant impact on their sensitivity and responsiveness to diquat, whereas food acted as a modulating factor of toxicant-induced mortality. The time course of effects was adequately described by the model, which thus appears suitable to analyse long-term effects of complex exposure patterns based upon full life cycle experiment data. Obtained model outputs (e.g. no-effect concentrations) could be directly used for chemical risk assessment. PMID:20921047

  3. Does water chemistry affect the dietary uptake and toxicity of silver nanoparticles by the freshwater snail Lymnaea stagnalis?

    PubMed

    Oliver, Ana López-Serrano; Croteau, Marie-Noële; Stoiber, Tasha L; Tejamaya, Mila; Römer, Isabella; Lead, Jamie R; Luoma, Samuel N

    2014-06-01

    Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important. Published by Elsevier Ltd.

  4. Two proteolytic fragments of menin coordinate the nuclear transcription and postsynaptic clustering of neurotransmitter receptors during synaptogenesis between Lymnaea neurons

    PubMed Central

    Getz, Angela M.; Visser, Frank; Bell, Erin M.; Xu, Fenglian; Flynn, Nichole M.; Zaidi, Wali; Syed, Naweed I.

    2016-01-01

    Synapse formation and plasticity depend on nuclear transcription and site-specific protein targeting, but the molecular mechanisms that coordinate these steps have not been well defined. The MEN1 tumor suppressor gene, which encodes the protein menin, is known to induce synapse formation and plasticity in the CNS. This synaptogenic function has been conserved across evolution, however the underlying molecular mechanisms remain unidentified. Here, using central neurons from the invertebrate Lymnaea stagnalis, we demonstrate that menin coordinates subunit-specific transcriptional regulation and synaptic clustering of nicotinic acetylcholine receptors (nAChR) during neurotrophic factor (NTF)-dependent excitatory synaptogenesis, via two proteolytic fragments generated by calpain cleavage. Whereas menin is largely regarded as a nuclear protein, our data demonstrate a novel cytoplasmic function at central synapses. Furthermore, this study identifies a novel synaptogenic mechanism in which a single gene product coordinates the nuclear transcription and postsynaptic targeting of neurotransmitter receptors through distinct molecular functions of differentially localized proteolytic fragments. PMID:27538741

  5. Inverse Relationship between Basal Pacemaker Neuron Activity and Aversive Long-Term Memory Formation in Lymnaea stagnalis

    PubMed Central

    Dong, Nancy; Feng, Zhong-Ping

    2017-01-01

    Learning and memory formation are essential physiological functions. While quiescent neurons have long been the focus of investigations into the mechanisms of memory formation, there is increasing evidence that spontaneously active neurons also play key roles in this process and possess distinct rules of activity-dependent plasticity. In this study, we used a well-defined aversive learning model of aerial respiration in the mollusk Lymnaea stagnalis (L. stagnalis) to study the role of basal firing activity of the respiratory pacemaker neuron Right Pedal Dorsal 1 (RPeD1) as a determinant of aversive long-term memory (LTM) formation. We investigated the relationship between basal aerial respiration behavior and RPeD1 firing activity, and examined aversive LTM formation and neuronal plasticity in animals exhibiting different basal aerial respiration behavior. We report that animals with higher basal aerial respiration behavior exhibited early responses to operant conditioning and better aversive LTM formation. Early behavioral response to the conditioning procedure was associated with biphasic enhancements in the membrane potential, spontaneous firing activity and gain of firing response, with an early phase spanning the first 2 h after conditioning and a late phase that is observed at 24 h. Taken together, we provide the first evidence suggesting that lower neuronal activity at the time of learning may be correlated with better memory formation in spontaneously active neurons. Our findings provide new insights into the diversity of cellular rules of plasticity underlying memory formation. PMID:28101006

  6. Testosterone levels and fecundity in the hermaphroditic aquatic snail Lymnaea stagnalis exposed to testosterone and endocrine disruptors.

    PubMed

    Giusti, Arnaud; Ducrot, Virginie; Joaquim-Justo, Célia; Lagadic, Laurent

    2013-08-01

    Endocrine disruptors are known to alter endogenous free and esterified levels of androgenic and estrogenic steroid hormones in aquatic mollusks. The origin of steroids in these animals, however, remains controversial. In the present study, free and esterified testosterone concentrations were measured in the hermaphroditic aquatic gastropod Lymnaea stagnalis exposed to molecules known for their androgenic (testosterone and tributyltin), anti-androgenic (cyproterone-acetate), and estrogenic (chlordecone) properties, by reference to their mode of action in vertebrates. In parallel, snail oviposition and fecundity were followed over a 21-d exposure period. Testosterone exposure resulted in increased esterified testosterone levels, whereas free testosterone concentrations remained stable. In contrast, cyproterone-acetate significantly increased the free form of testosterone with no changes in the esterified form, whereas chlordecone showed a tendency to reduce (though not significantly) esterified testosterone concentrations without changing free testosterone levels. Finally, tributyltin did not alter testosterone homeostasis. The production of egg clutches and eggs was significantly reduced only in the snails exposed to the highest concentrations of chlordecone (19.6 µg/L) and tributyltin (94.2 ng Sn/L). Overall, the present study demonstrates that uptake of testosterone from the exposure medium occurs in L. stagnalis. Moreover, it shows that cyproterone-acetate and, to a lesser extent, chlordecone can alter endogenous testosterone levels in this freshwater snail. However, the relationship between hormonal changes and snail reproduction has not been established. Environ Toxicol Chem 2013;32:1740-1745. © 2013 SETAC.

  7. Modelling effects of diquat under realistic exposure patterns in genetically differentiated populations of the gastropod Lymnaea stagnalis.

    PubMed

    Ducrot, Virginie; Péry, Alexandre R R; Lagadic, Laurent

    2010-11-12

    Pesticide use leads to complex exposure and response patterns in non-target aquatic species, so that the analysis of data from standard toxicity tests may result in unrealistic risk forecasts. Developing models that are able to capture such complexity from toxicity test data is thus a crucial issue for pesticide risk assessment. In this study, freshwater snails from two genetically differentiated populations of Lymnaea stagnalis were exposed to repeated acute applications of environmentally realistic concentrations of the herbicide diquat, from the embryo to the adult stage. Hatching rate, embryonic development duration, juvenile mortality, feeding rate and age at first spawning were investigated during both exposure and recovery periods. Effects of diquat on mortality were analysed using a threshold hazard model accounting for time-varying herbicide concentrations. All endpoints were significantly impaired at diquat environmental concentrations in both populations. Snail evolutionary history had no significant impact on their sensitivity and responsiveness to diquat, whereas food acted as a modulating factor of toxicant-induced mortality. The time course of effects was adequately described by the model, which thus appears suitable to analyse long-term effects of complex exposure patterns based upon full life cycle experiment data. Obtained model outputs (e.g. no-effect concentrations) could be directly used for chemical risk assessment.

  8. Octopamine-containing (OC) interneurons enhance central pattern generator activity in sucrose-induced feeding in the snail Lymnaea.

    PubMed

    Vehovszky, Agnes; Szabó, Henriette; Elliott, Christopher J H

    2004-10-01

    In the pond snail Lymnaea stagnalis octopamine-containing (OC) interneurons trigger and reconfigure the feeding pattern in isolated CNS by excitation of the central pattern generator. In semi-intact (lip-mouth-CNS) preparations, this central pattern generator is activated by chemosensory inputs. We now test if sucrose application to the lips activates the OC neurons independently of the rest of the feeding central pattern generator, or if the OC interneuron is activated by inputs from the feeding network. In 66% of experiments, sucrose stimulated feeding rhythms and OC interneurons received regular synaptic inputs. Only rarely (14%) did the OC interneuron fire action potentials, proving that firing of OC interneurons is not necessary for the sucrose-induced feeding. Prestimulation of OC neurons increased the intensity and duration of the feeding rhythm evoked by subsequent sucrose presentations. One micromolar octopamine in the CNS bath mimicked the effect of OC interneuron stimulation, enhancing the feeding response when sucrose is applied to the lips. We conclude that the modulatory OC neurons are not independently excited by chemosensory inputs to the lips, but rather from the buccal central pattern generator network. However, when OC neurons fire, they release modulatory octopamine, which provides a positive feedback to the network to enhance the sucrose-activated central pattern generator rhythm.

  9. Molluscicidal activity of Ferula asafoetida, Syzygium aromaticum and Carum carvi and their active components against the snail Lymnaea acuminata.

    PubMed

    Kumar, Pradeep; Singh, D K

    2006-06-01

    The molluscicidal activity of dried root latex powder of Ferula asafoetida, flower-bud powder of Syzygium aromaticum and seed powder of Carum carvi against the snail Lymnaea acuminata was studied. The molluscicidal activity of all the three plant products was found to be both time and concentration dependent. The toxicity of S. aromaticum flower-bud powder (96 h LC(50):51.98 mg/l) was more pronounced than that of root latex powder of F. asafoetida (96 h LC(50):82.71 mg/l) and seed powder of C. carvi (96 h LC(50):140.58 mg/l). Ethanol extract was more toxic than other organic extracts. The ethanol extract of S. aromaticum (24h LC(50):83.53 mg/l) was more effective than that of F. asafoetida (24h LC(50):132.31 mg/l) and C. carvi (24h LC(50):130.61 mg/l) in killing the test animals. The 96 h LC(50) of column purified fraction of seed powder of C. carvi was 5.40 mg/l whereas those of flower-bud powder of S. aromaticum and dried root latex powder of F. asafoetida were 7.87 and 9.67 mg/l, respectively. The product of F. asafoetida, S. aromaticum and C. carvi may be used as potent molluscicides.

  10. Relationship between the grades of a learned aversive-feeding response and the dopamine contents in Lymnaea

    PubMed Central

    Aonuma, Hitoshi; Kaneda, Mugiho; Hatakeyama, Dai; Watanabe, Takayuki; Lukowiak, Ken

    2016-01-01

    ABSTRACT The pond snail Lymnaea learns conditioned taste aversion (CTA) and remembers not to respond to food substances that initially cause a feeding response. The possible relationship between how well snails learn to follow taste-aversion training and brain dopamine contents is not known. We examined this relationship and found the following: first, snails in the act of eating just before the commencement of CTA training were poor learners and had the highest dopamine contents in the brain; second, snails which had an ad libitum access to food, but were not eating just before training, were average learners and had lower dopamine contents; third, snails food-deprived for one day before training were the best learners and had significantly lower contents of dopamine compared to the previous two cohorts. There was a negative correlation between the CTA grades and the brain dopamine contents in these three cohorts. Fourth, snails food-deprived for five days before training were poor learners and had higher dopamine contents. Thus, severe hunger increased the dopamine content in the brain. Because dopamine functions as a reward transmitter, CTA in the severely deprived snails (i.e. the fourth cohort) was thought to be mitigated by a high dopamine content. PMID:27815244

  11. The Early Worm Catches the Bird? Productivity and Patterns of Trichobilharzia szidati Cercarial Emission from Lymnaea stagnalis

    PubMed Central

    Sures, Bernd

    2016-01-01

    Digenean trematodes are common and abundant in aquatic habitats and their free-living larvae, the cercariae, have recently been recognized as important components of ecosystems in terms of comprising a significant proportion of biomass and in having a potentially strong influence on food web dynamics. One strategy to enhance their transmission success is to produce high numbers of cercariae which are available during the activity peak of the next host. In laboratory experiments with 13 Lymnaea stagnalis snails infected with Trichobilharzia szidati the average daily emergence rate per snail was determined as 2,621 cercariae, with a maximum of 29,560. During a snail’s lifetime this summed up to a mass equivalent of or even exceeding the snail’s own body mass. Extrapolated for the eutrophic pond where the snails were collected, annual T. szidati biomass may reach 4.65 tons, a value equivalent to a large Asian elephant. Emission peaks were observed after the onset of illumination, indicating emission synchronizing with the high morning activities of the definitive hosts, ducks. However, high cercarial emission is possible throughout the day under favorable lightning conditions. Therefore, although bird schistosomes, such as T. szidati constitute only a fraction of the diverse trematode communities in the studied aquatic ecosystem, their cercariae can still pose a considerable risk for humans of getting cercarial dermatitis (swimmer's itch) due to the high number of cercariae emitted from infected snails. PMID:26895541

  12. A comparative study of haemocytes from resistant and susceptible Lymnaea natalensis snails exposed to Fasciola gigantica miracidia.

    PubMed

    El-Sayed, Kamelia A; El-Din, Abdel-hakim saad; Gad EL-KAarim, Rasha M

    2014-12-01

    Effect ot infection with Fasciola gigantica on total and differential haemocytes count of resistant and susceptible Lymnaea natalensis snails were studied. Exposure of L. natalensis resistant and susceptible strains to F. gigantica on miracidia caused gradual increase in the number of circulating haemocytes at the same time of exposure. In susceptible strain, the increase in the number of circulating haemocytes became significant at the second week post exposure being 2560 cell/ml (p

  13. Distribution and habitats of the snail Lymnaea truncatula, intermediate host of the liver fluke Fasciola hepatica, in South Africa.

    PubMed

    de Kock, K N; Wolmarans, C T; Bornman, M

    2003-12-01

    This paper focuses on the geographical distribution and habitats of Lymnaea truncatula, the intermediate, snail host of the liver fluke, Fasciola hepatica, as reflected by the 723 samples in the database of the National Freshwater Snail Collection, Potchefstroom, South Africa. The 221 different loci (1/16-degree squares) on record reflect an extensive but discontinuous distribution, except in Lesotho and in parts of the Mpumalanga, Gauteng and North West provinces of South Africa. Although recorded from 12 different types of waterbody, it was mostly (42.0%) recovered from swamps. Most samples (45.8%) were collected in habitats with slow-flowing water. A muddy substratum was recorded for 62.5% of the samples. Most samples (86.3%) were collected in habitats with a mean annual air temperature of 10-20 degrees C, and more than 69% came from localities with a mean annual rainfall of 600-900 mm. An integrated decision tree constructed from the data indicated that temperature and types of waterbody play a decisive role in determining the presence of L. truncatula in a given area. A temperature index calculated for all mollusc species ranked L. truncatula second in a total of 53 species according to its association with low temperatures. It remains to be established whether its distribution is indeed discontinuous, and whether its preference for a particular habitat, amphibious habits and ability to aestivate could have resulted in some populations having been overlooked during surveys.

  14. Aspects of the maintenance of the life cycle of Fasciola hepatica in Lymnaea columella in Minas Gerais, Brazil.

    PubMed

    de Souza, Cecília Pereira; Magalhaes, Kelly Grace; Passos, Liana Konovaloff Jannotti; Pereira dos Santos, Glaucia Cristina; Ribeiro, Fabio; Katz, Naftale

    2002-04-01

    Fascioliasis is a parasitic disease of domestic ruminants that occurs worldwide. The lymnaeid intermediate hosts of Fasciola hepatica include Lymnaea columella, which is widely distributed in Brazil. A colony of L. columella from Belo Horizonte, MG, was reared in our laboratory to be used in studies of the F. hepatica life cycle, the intermediate host-parasite relationship and development of an anti-helminthic vaccine. In the first experiment 1,180 snails were exposed to miracidia of F. hepatica eggs removed from the biliary tracts of cattle from the State of Rio Grande do Sul. In the second and third experiments the snails were exposed to miracidia that had emerged from F. hepatica eggs from Uruguay, maintained in rabbits. The rates of infection in the first, second and third experiments were 0, 42.1 and 0% respectively. Over 15,806 metacercariae were obtained and stored at 4 degrees C. Four rabbits weighing 1.5 kg each were infected with 32-44 metacercariae and two with 200. Three rabbits begin to eliminate eggs of the parasite in the feces from 84 days after infection onwards. The biological cycle of F. hepatica in L. columella and the rabbit was completed within 124 days.

  15. Exposure to Fasciola hepatica miracidia increases the sensitivity of Lymnaea (Fossaria) humilis to high and low pH.

    PubMed

    Cruz-Mendoza, I; Naranjo-García, E; Quintero-Martínez, M T; Ibarra-Velarde, F; Correa, D

    2006-06-01

    Humidity and temperature have been considered important factors affecting the infectivity of Fasciola hepatica to its molluscan host. One hundred and thirty laboratory-reared Lymnaea humilis were exposed for 4 hr to the miracidia of F. hepatica over a pH range from 4.0 to 10.0, and their rates of survival were compared with 130 similarly treated but unexposed control snails. All control snails died within 24 hr at pH 4.0, but they showed better survival at pH 5.0-10.0. Their sensitivity to solutions with high and low pH, however, was increased if kept in the presence of F. hepatica miracidia. Snails exposed at pH 5.0 died within 24 hr, whereas most other pHs also affected survival such that by day 18 only those snails exposed at pH 7.2 remained alive. The increased sensitivity of the snails to pH could be explained by a damage-mediated release of parasite enzymes, because infectivity was highest at pHs associated with the lowest host mortality.

  16. The stress of Lymnaea truncatula just before miracidial exposure with Fasciola hepatica increased the prevalence of infection.

    PubMed

    Abrous, M; Rondelaud, D; Dreyfuss, G

    2001-09-01

    Single-miracidium infections of Lymnaea truncatula with Fasciola hepatica were carried out under laboratory conditions to determine whether the stress of snails just before miracidial exposure had any influence on the prevalence of Fasciola infection, redial burden, and cercarial shedding. Three methods, i.e., the fasting of L. truncatula for 3 days in water filtered through a Millipore membrane, the effect of 6-8 degrees C water for 15 min, or the immersion of L. truncatula in a detergent solution at low concentration for 15 min, were used to stress snails. Enhanced susceptibility of snails to F. hepatica infection was noted in stressed groups (93-96% vs 48-50% in controls). The number of free rediae did not show any variation in controls as well as in stressed groups, except for fasted snails in which free rediae were significantly fewer. No differences in cercarial production between controls and the cold group were noted. Fasting, cold shock, or detergent exposure prior to exposure to F. hepatica miracidia might have weakened the snails so that they were not as efficient in avoiding miracidial penetration, thus leading to higher infection rates. Copyright 2001 Academic Press.

  17. Southernmost finding of Lymnaea viatrix orbigny, 1835 (Pulmonata: Lymnaeidae), intermediate host of Fasciola hepatica (Linnaeus, 1758) (Trematoda: Digenea), in urban and rural areas of Patagonia, Argentina.

    PubMed

    Kleiman, Florencia; Pietrokovsky, Silvia; Paraense, W Lobato; Wisnivesky-Colli, Cristina

    2004-02-01

    We report the first finding of Lymnaea viatrix south of parallel 41 masculine S, in rural and urban areas from Argentina. Ninety snails were collected during year 2000, from a concrete pond at a Public Square in El Bolsón Village, Río Negro province, and 811 snails in November 1999, and during 2000 from waterbodies within a farm at Cholila locality, Chubut province. Fasciola hepatica infection was detected in 0.9% snails from the rural area. We discuss the potential risk of L. viatrix to public health in urban areas and its epidemiological importance in rural areas of the Andean Patagonian region.

  18. Combination of molluscicides with attractant carbohydrates and amino acids in bait formulation against the snail Lymnaea acuminata.

    PubMed

    Kumar, P; Singh, V K; Singh, D K

    2011-05-01

    Fascioliasis is an important helminth disease caused by Fasciola (F.) hepatica and F gigantica of Asia and Africa. This disease belongs to the plant-borne trematode zoonoses. Human infection has been reported in 51 different countries from 5 continents. One of the possible approaches to control this problem is to interrupt the life cycle of the parasitic trematodes by eliminating the snail. Snails attractant pellets (SAP) were prepared from binary combination of carbohydrate + amino acid (20 mM) in 2% agar solution with active molluscicidal component Ferula asafoetida (ferulic acid, umbelliferone), Syzygium aromaticum (eugenol), Carum carvi (limonene). Attraction of snails to different combinations was studied by using clear glass aquaria having diameter of 30 cm. Each aquarium was divided into four concentric zones; zone-3 (central zone), zone-2 and zone-1 (middie zone) and zone-0 (outer zone) had a diameter of 13, 18, 24, and 30 cm, respectively. The behavioral responses of snails to these binary combinations of carbohydrate and amino acid in bait formulation were examined. The fraction of snails that was in contact with the SAP at different times was used as a measure of attraction. Among all the binary combination of carbohydrate+amino acid+molluscicide after 2h of experiment, highest attraction of snail (54.71%) was observed towards the SAP containing starch+histidine+limolene. Limonene+ starch+histidine containing SAP emerged as the strongest bait formulation (96h LC50 0.74%) against Lymnaea acuminata. The present study suggested that the molluscicides of plant origin could be used with varying degrees of success in bait formulation.

  19. The electrotonic location of low-resistance intercellular junctions between a pair of giant neurones in the snail Lymnaea.

    PubMed Central

    Benjamin, P R; Pilkington, J B

    1986-01-01

    The passive electrotonic properties of neurones VD1 and RPD2 in the brain of the snail Lymnaea can be represented by a soma-finite cable model with closed-circuit axon termination. There is a considerable individual variation in input resistance, membrane time constant, electrotonic length and axon-soma conductance ratio, but the average values for these parameters are similar in the two neurones. The cells are tightly coupled by an electrotonic synapse giving an average steady-state coupling coefficient of 0.68 and an average resistance measured between recording sites in the cell bodies of 20 M omega. Calculations using a model consisting of a symmetrical pair of cells with standard values for the electrotonic parameters show that in this system, for a soma-soma resistance of 20 M omega, the junction cannot be more than 0.16 length constants from the cell bodies. Reduction in coupling due to membrane current losses in such short proximal axon segments is insignificant. Intra-axonal recordings indicate that most of the coupling resistance is located at the junction between VD1 and RPD2, which must therefore be closer to the cell bodies than the limiting value of 0.16 length constants assuming an electrical equivalent model which includes the standard electrotonic parameters. If all the soma-soma resistance is located at the junction, then it could be physically a single array of gap-junction particles. Despite its low conductance (1/20 M omega = 50 nS) and possibly small physical dimensions, the electrotonic synapse is more than sufficient to ensure spike synchrony in the two cells. PMID:3958976

  20. Molecular Evidence of Trichobilharzia Species (Digenea: Schistosomatidae) in the Snails of Lymnaea auricularia from Urmia Suburb, North West Iran

    PubMed Central

    YAKHCHALI, Mohammad; HOSSEINPANAHI, Asaad; MALEKZADEH-VIAYEH, Reza

    2016-01-01

    Background: The present study was carried out to detect the infection of larval stages of Trichobilharzia species in the snail Lymnaea auricularia in northwestern Iran based on DNA analysis. Methods: A total number of 320 snails of L. auricularia were sampled from four water-bodies located in the suburb of Urmia City, North West Iran, during May to November 2011. The snails were first microscopically inspected for the infection with larval stages of trematodes. Genomic DNA was extracted from the snails and PCR was performed to amplify a fragment of the ribosomal DNA of Trichobilharzia species in the infected snails. Results: Microscopic examinations indicated that 11.25% (36 out of 320) of the snails were infected with larval stages of trematodes, while the PCR patterns showed a much higher infection rate (31.25%, 100/320). According to the PCR, the infections were caused by the larval stages of T. szidati (21.56%, 69/320) and T. franki (9.69%, 31/320) or both of them (8.44%, 27/320). The infected snails were observed in three out of the four studied sites. The highest infection rate in a single site was 50% (25/50). Only 7.81% (25 out of 320) of the infected snails were from the plain areas, while the remaining was from high altitudes. Conclusion: Results of this study contribute the utility of the employed technique for quick and accurate detection of the infection with trichobilharzian species in their intermediate host snails, which may have potential zoonotic role in the region. PMID:28127334

  1. Proteomic Analysis of the Reproductive Organs of the Hermaphroditic Gastropod Lymnaea stagnalis Exposed to Different Endocrine Disrupting Chemicals

    PubMed Central

    Giusti, Arnaud; Leprince, Pierre; Mazzucchelli, Gabriel; Thomé, Jean-Pierre; Lagadic, Laurent; Ducrot, Virginie; Joaquim-Justo, Célia

    2013-01-01

    Many studies have reported perturbations of mollusc reproduction following exposure to low concentrations (ng/L range) of endocrine disrupting chemicals (EDCs). However, the mechanisms of action of these molecules on molluscs are still poorly understood. Investigation of the modifications of protein expression in organisms exposed to chemicals using proteomic methods can provide a broader and more comprehensive understanding of adverse impacts of pollution on organisms than conventional biochemical biomarkers (e.g., heat-shock proteins, metallothioneins, GST, EROD). In this study we have investigated the impacts of four chemicals, which exhibit different endocrine disrupting properties in vertebrates, on the proteome of the hermaphroditic freshwater pulmonate gastropod Lymnaea stagnalis after 21 days of exposure. Testosterone, tributyltin, chlordecone and cyproterone acetate were chosen as tested compounds as they can induce adverse effects on the reproduction of this snail. The 2D-DIGE method was used to identify proteins whose expression was affected by these compounds. In addition to modifying the expression of proteins involved in the structure and function of the cytoskeleton, chemicals had impacts on the expression of proteins involved in the reproduction of L. stagnalis. Exposure to 19.2 µg/L of chlordecone increased the abundance of ovipostatin, a peptide transmitted during mating through seminal fluid, which reduces oviposition in this species. The expression of yolk ferritin, the vitellogenin equivalent in L. stagnalis, was reduced after exposure to 94.2 ng Sn/L of tributyltin. The identification of yolk ferritin and the modification of its expression in snails exposed to chemicals were refined using western blot analysis. Our results showed that the tested compounds influenced the abundance of yolk ferritin in the reproductive organs. Alteration in proteins involved in reproductive pathways (e.g., ovipostatin and yolk ferritin) could constitute relevant

  2. Fasciola gigantica: cercarial shedding pattern from Lymnaea natalensis after long-term exposure to cadmium at different temperatures.

    PubMed

    Soliman, Maha F M

    2009-04-01

    Little is known about the response of Fasciola spp., inside its snail host to pollutant toxicity. The effect of long-term exposure of Lymnaea natalensis to 0.1 microg/l, 10 microg/l, or 100 microg/l cadmium (Cd) on the infection rates with F. gigantica, percentage of cercariae-shedding snails and cercariae shedding pattern was investigated. The snails were exposed to Cd for 7 days either pre-infection with single Fasciola miracidium or during the late pre-patent period of the infection. The possible interaction between metal exposure and acclimatization temperature was also studied in three ranges; 16-18 degrees C, 23-25 degrees C and 30-32 degrees C. Results clearly showed that host exposure to 100 microg/l Cd significantly affected the pattern of Fasciola development inside its snail host, and that the acclimatization temperature was a key factor affecting the role played by Cd. Pre-infection exposure to Cd caused a significant reduction in the infection rates where the effect was temperature-dependent. Post-infection exposure to Cd significantly increased the percentage of cercariae-shedding snails; the effect was temperature-independent. Interestingly, post-infection exposure significantly altered the differential cercarial output pattern, while no clear impact on the total was found. The alteration in the differential cercarial output was represented as a significantly higher proportion of floating metacercaria as compared to fixed ones and also higher proportion of dead cercariae which may directly reduce the transmission of Fasciola to the final host. The mechanisms of cadmium impact are briefly discussed.

  3. Highland populations of Lymnaea truncatula infected with Fasciola hepatica survive longer under experimental conditions than lowland ones.

    PubMed

    Vignoles, P; Favennec, L; Dreyfuss, G; Rondelaud, D

    2002-04-01

    A retrospective study was carried out on the experimental infections of Lymnaea truncatula with Fasciola hepatica performed over the last 20 years to determine if the populations of snails living in highland or lowland countries had the same ability to sustain trematode larval development. The six highland populations originated from the Peruvian Altiplano (altitude 2,800 m), the French Alps (2,300 m), and the Massif Central (900-1,400 m), whereas the 13 lowland populations came from different sites located in central France (90-250 m). Bimiracidial infections of 4-mm-high snails were performed to study cercarial shedding and to quantify their redial burden. Compared to lowland populations, snail survival at day 30 post-exposure was significantly higher in the highland L. truncatula (57-75% compared to 31-45%) and their lifespan was greater (a mean of 87-96 days for cercaria-shedding snails compared to 64-77 days). The prevalences of F. hepatica infections, the numbers of free rediae within snail bodies, and the numbers of cercariae did not show any significant differences between highland and lowland snails although the numbers of cercariae were clearly higher in the Peruvian and three French highland populations of L. truncatula. The long survival times of highland snails under laboratory conditions might be an adaptation of these L. truncatula to the more extreme highland climate. The better ability of highland snails to sustain parasite larval development suggests that they would be better intermediate hosts in the life cycle of F. hepatica than lowland populations.

  4. Interactions between cyanobacteria and gastropods II. Impact of toxic Planktothrix agardhii on the life-history traits of Lymnaea stagnalis.

    PubMed

    Lance, Emilie; Paty, Chrystelle; Bormans, Myriam; Brient, Luc; Gérard, Claudia

    2007-03-30

    Hepatotoxins are frequently produced by many cyanobacterial species. Microcystins (MCs) are the most frequent and widely studied hepatotoxins, with potentially hazardous repercussions on aquatic organisms. As a ubiquitous herbivore living in eutrophic freshwaters, the snail Lymnaea stagnalis (Gastropoda: Pulmonata) is particularly exposed to cyanobacteria. The toxic filamentous Planktothrix agardhii is common in temperate lakes and is therefore, a potential food resource for gastropods. In the first part of this study, we demonstrated the ingestion of toxic P. agardhii by L. stagnalis during a 5 weeks exposure, with concomitant accumulation of, on average, 60% of total MCs ingested. After 3 weeks of non-toxic food (lettuce), approximately 90% of MCs were eliminated from tissues. Here, we investigate the impact of toxic P. agardhii consumption on the life-history traits (survival, growth and fecundity), locomotion and the structure of digestive and genital glands of juvenile and adult L. stagnalis. We observed a decrease of growth regardless of age, although this was more marked in juveniles, and a reduction of fecundity in adults. Survival and locomotion were not affected. Reduction of growth and fecundity continued to be observed even after feeding of non-toxic food for 3 weeks. The structure of the digestive gland was altered during the intoxication period but not irreversibly as cells tended to recover a normal status after the 3-week detoxification period. No histopathological changes occurred in the genital gland and oocytes, and spermatozoids were present in the gonadic acini. The density of cyanobacterial suspensions used in this study was comparable to those regularly observed in lakes, particularly in eutrophic waters. These results are discussed in terms of the negative impact of toxic cyanobacteria on natural communities of freshwater gastropods, and potential cascading effects on the equilibrium and functioning of the ecosystem.

  5. Aptitude of Lymnaea palustris and L. stagnalis to Fasciola hepatica larval development through the infection of several successive generations of 4-mm-high snails.

    PubMed

    Vignoles, P; Rondelaud, D; Dreyfuss, G

    2016-06-01

    Bimiracidial infections of Lymnaea palustris and Lymnaea stagnalis (shell height at exposure, 4 mm) with Fasciola hepatica were carried out during six successive snail generations to determine if prevalence and intensity of snail infection increased over time through descendants issuing from eggs laid by parents already exposed to this digenean. Controls were constituted by a French population of Galba truncatula (a single generation) infected according to the same protocol. In a first experiment performed with the F1 to F5 generations of L. palustris, the prevalence and intensity of F. hepatica infection in snails progressively increased. Immature rediae and a few cercariae-containing rediae of the digenean were observed in L. stagnalis from the F3 generation, but no free cercaria was noted in the bodies of this lymnaeid from the F4 to F6 generations. In another experiment carried out with the F6 generation of L. palustris, the prevalence of F. hepatica infection and the number of shed cercariae were significantly lower in L. palustris than in G. truncatula. This mode of snail infection suggests an explanation for cases of human fasciolosis occurring in central France after the collection of wild watercress from beds where L. palustris was the sole lymnaeid.

  6. Direct mass spectrometric peptide profiling and sequencing of nervous tissues to identify peptides involved in male copulatory behavior in Lymnaea stagnalis

    NASA Astrophysics Data System (ADS)

    Dreisewerd, Klaus; Kingston, Robert; Geraerts, Wijnand P. M.; Li, Ka Wan

    1997-12-01

    Matrix-assisted laser desorption mass spectrometry (MALDI-MS) was performed directly on a small piece of single penis nerve of the pond snail, Lymnaea stagnalis, and reveals the presence of complex peptide profiles, including many hitherto undescribed peptides. Two of the peptides have molecular weights corresponding exactly to the previously described Lymnaea small cardioactive peptides (SCP) A and B. We confirmed their identities by structural characterization of the two peptides directly from a single penis nerve by matrix-assisted laser desorption ionization high-energy collision tandem MS analysis. MALDI-MS of nervous tissues also demonstrates that a cluster of central neurons, which send their axons to the penis nerve, contain the two peptides. As the penis nerve is the nerve that innervates the penis complex, we propose that the peptides are involved in the modulation of male copulatory processes. A bioassay indeed showed that the peptides increase the contraction frequency of the vas deference in a dose-dependent manner. The results demonstrate the potential of direct MALDI-MS analysis of nervous tissue to complement or substitute conventional biochemical techniques for the identification and localization of neuropeptides.

  7. The effect of abiotic factors on the toxicity of cypermethrin against the snail Lymnaea acuminata in the control of fascioliasis.

    PubMed

    Singh, V; Singh, D K

    2009-03-01

    Every month during the year 2006-2007, the 24, 48, 72 and 96 h LC50 values of a molluscicide, cypermethrin, were determined for a snail Lymnaea acuminata, with concomitant estimation of levels of temperature, pH, dissolved oxygen and carbon dioxide and electrical conductivity, both in control and test water. On the basis of a 24 h toxicity assay, it was noted that LC50 values of 10.39, 10.90 and 11.19 mg l- 1 during the months of May, June and July, respectively, were most effective in killing the snails, while the molluscicide was least effective in the month of January, when its 24 h LC50 was 65.84 mg l- 1.There was a significant positive correlation between LC50 of cypermethrin and levels of dissolved O2/pH of water in corresponding months. On the contrary, a negative correlation was observed between LC50 and dissolved CO2/temperature of test water in the same months. In order to ascertain that such a relationship between toxicity and abiotic factors is not coincidental, the nervous tissue of the snail was assayed for the activity of acetylcholinesterase (AChE), acid phosphatase (ACP) and alkaline phosphatase (ALP) to sublethal concentrations (40% and 80%) of 24 h LC50 during each of the 12 months of the same year. The findings confirmed that abiotic factors indeed influence toxicity of cypermethrin in the snail. A significant positive rank correlation between AChE, ACP and ALP activity did exist following exposure to the corresponding sublethal concentrations. Moreover, there was a maximum inhibition of 61.29 and 76.16% of AChE and ACP, respectively, in snails exposed to 80% of the 24 h LC50 in the month of May. A similar treatment caused a maximum inhibition of 70.53% of ALP activity in the month of June. This work shows conclusively that the best time to control the snail population with cypermethrin is during the months of May and June.

  8. Adaptation of Lymnaea fuscus and Radix balthica to Fasciola hepatica through the experimental infection of several successive snail generations

    PubMed Central

    2014-01-01

    Background High prevalence of Fasciola hepatica infection (>70%) was noted during several outbreaks before the 2000s in several French farms where Galba truncatula is lacking. Other lymnaeids such as Lymnaea fuscus, L. glabra and/or Radix balthica are living in meadows around these farms but only juvenile snails can sustain complete larval development of F. hepatica while older snails were resistant. The low prevalence of infection (<20%) and limited cercarial production (<50 cercariae per infected snail) noted with these juveniles could not explain the high values noted in these cattle herds. As paramphistomosis due to Calicophoron daubneyi was not still noted in these farms, the existence of another mode of infection was hypothesized. Experimental infection of several successive generations of L. glabra, originating from eggs laid by their parents already infected with this parasite resulted in a progressive increase in prevalence of snail infection and the number of shed cercariae. The aim of this paper was to determine if this mode of snail infection was specific to L. glabra, or it might occur in other lymnaeid species such as L. fuscus and R. balthica. Methods Five successive generations of L. fuscus and R. balthica were subjected to individual bimiracidial infections in the laboratory. Resulting rediae and cercariae in the first four generations were counted after snail dissection at day 50 p.e. (20°C), while the dynamics of cercarial shedding was followed in the F5 generation. Results In the first experiment, prevalence and intensity of F. hepatica infection in snails progressively increased from the F1 (R. balthica) or F2 (L. fuscus) generation. In the second experiment, the prevalence of F. hepatica infection and the number of shed cercariae were significantly lower in L. fuscus and R. balthica (without significant differences between both lymnaeids) than in G. truncatula. Conclusion The F. hepatica infection of several successive snail generations

  9. Histopathology and microcystin distribution in Lymnaea stagnalis (Gastropoda) following toxic cyanobacterial or dissolved microcystin-LR exposure.

    PubMed

    Lance, Emilie; Josso, Celine; Dietrich, Daniel; Ernst, Bernhard; Paty, Chrystelle; Senger, Fabrice; Bormans, Myriam; Gérard, Claudia

    2010-07-01

    The accumulation of hepatotoxic microcystins (MCs) in gastropods has been demonstrated to be higher following grazing of toxic cyanobacteria than from MCs dissolved in ambient water. Previous studies, however, did not adequately consider MCs covalently bound to protein phosphatases, which may represent a considerably part of the MC body burden. Thus, using an immunohistochemical method, we examined and compared the histopathology and organ distribution of covalently bound MCs in Lymnaea stagnalis following a 5-week exposure to (i) dmMC-LR, dmMC-RR, and MC-YR-producing Planktothrix agardhii (5 microg MC-LReqL(-1)) and (ii) dissolved MC-LR (33 and 100 microgL(-1)). A subsequent 3-week depuration investigated potential MC elimination and tissue regeneration. Following both exposures, bound MCs were primarily observed in the digestive gland and tract of L. stagnalis. Snails exposed to toxic cyanobacteria showed severe and widespread necrotic changes in the digestive gland co-occurring with a pronounced cytoplasmic presence of MCs in digestive cells and in the lumen of digestive lobules. Snails exposed to dissolved MC-LR showed moderate and negligible pathological changes of the digestive gland co-occurring with a restrained presence of MCs in the apical membrane of digestive cells and in the lumen of digestive lobules. These results confirm lower uptake of dissolved MC-LR and correspondingly lower cytotoxicity in the digestive gland of L. stagnalis. In contrast, after ingestion of MC-containing cyanobacterial filaments, the most likely longer residual time within the digestive gland and/or the MC variant involved (e.g., MC-YR) allowed for increased MC uptake, consequently a higher MC burden in situ and thus a more pronounced ensuing pathology. While no pathological changes were observed in kidney, foot and the genital gland, MCs were detected in spermatozoids and oocytes of all exposed snails, most likely involving a hemolymph transport from the digestive system to the

  10. Adaptation of Lymnaea fuscus and Radix balthica to Fasciola hepatica through the experimental infection of several successive snail generations.

    PubMed

    Rondelaud, Daniel; Titi, Amal; Vignoles, Philippe; Mekroud, Abdeslam; Dreyfuss, Gilles

    2014-07-01

    High prevalence of Fasciola hepatica infection (>70%) was noted during several outbreaks before the 2000s in several French farms where Galba truncatula is lacking. Other lymnaeids such as Lymnaea fuscus, L. glabra and/or Radix balthica are living in meadows around these farms but only juvenile snails can sustain complete larval development of F. hepatica while older snails were resistant. The low prevalence of infection (<20%) and limited cercarial production (<50 cercariae per infected snail) noted with these juveniles could not explain the high values noted in these cattle herds. As paramphistomosis due to Calicophoron daubneyi was not still noted in these farms, the existence of another mode of infection was hypothesized. Experimental infection of several successive generations of L. glabra, originating from eggs laid by their parents already infected with this parasite resulted in a progressive increase in prevalence of snail infection and the number of shed cercariae. The aim of this paper was to determine if this mode of snail infection was specific to L. glabra, or it might occur in other lymnaeid species such as L. fuscus and R. balthica. Five successive generations of L. fuscus and R. balthica were subjected to individual bimiracidial infections in the laboratory. Resulting rediae and cercariae in the first four generations were counted after snail dissection at day 50 p.e. (20°C), while the dynamics of cercarial shedding was followed in the F5 generation. In the first experiment, prevalence and intensity of F. hepatica infection in snails progressively increased from the F1 (R. balthica) or F2 (L. fuscus) generation. In the second experiment, the prevalence of F. hepatica infection and the number of shed cercariae were significantly lower in L. fuscus and R. balthica (without significant differences between both lymnaeids) than in G. truncatula. The F. hepatica infection of several successive snail generations, coming from parents infected with this

  11. Fascioliasis transmission by Lymnaea neotropica confirmed by nuclear rDNA and mtDNA sequencing in Argentina.

    PubMed

    Mera y Sierra, Roberto; Artigas, Patricio; Cuervo, Pablo; Deis, Erika; Sidoti, Laura; Mas-Coma, Santiago; Bargues, Maria Dolores

    2009-12-03

    Fascioliasis is widespread in livestock in Argentina. Among activities included in a long-term initiative to ascertain which are the fascioliasis areas of most concern, studies were performed in a recreational farm, including liver fluke infection in different domestic animal species, classification of the lymnaeid vector and verification of natural transmission of fascioliasis by identification of the intramolluscan trematode larval stages found in naturally infected snails. The high prevalences in the domestic animals appeared related to only one lymnaeid species present. Lymnaeid and trematode classification was verified by means of nuclear ribosomal DNA and mitochondrial DNA marker sequencing. Complete sequences of 18S rRNA gene and rDNA ITS-2 and ITS-1, and a fragment of the mtDNA cox1 gene demonstrate that the Argentinian lymnaeid belongs to the species Lymnaea neotropica. Redial larval stages found in a L. neotropica specimen were ascribed to Fasciola hepatica after analysis of the complete ITS-1 sequence. The finding of L. neotropica is the first of this lymnaeid species not only in Argentina but also in Southern Cone countries. The total absence of nucleotide differences between the sequences of specimens from Argentina and the specimens from the Peruvian type locality at the levels of rDNA 18S, ITS-2 and ITS-1, and the only one mutation at the mtDNA cox1 gene suggest a very recent spread. The ecological characteristics of this lymnaeid, living in small, superficial water collections frequented by livestock, suggest that it may be carried from one place to another by remaining in dried mud stuck to the feet of transported animals. The presence of L. neotropica adds pronounced complexity to the transmission and epidemiology of fascioliasis in Argentina, due to the great difficulties in distinguishing, by traditional malacological methods, between the three similar lymnaeid species of the controversial Galba/Fossaria group present in this country: L. viatrix

  12. Development and validation of an OECD reproductive toxicity test guideline with the pond snail Lymnaea stagnalis (Mollusca, Gastropoda).

    PubMed

    Ducrot, Virginie; Askem, Clare; Azam, Didier; Brettschneider, Denise; Brown, Rebecca; Charles, Sandrine; Coke, Maïra; Collinet, Marc; Delignette-Muller, Marie-Laure; Forfait-Dubuc, Carole; Holbech, Henrik; Hutchinson, Thomas; Jach, Arne; Kinnberg, Karin L; Lacoste, Cédric; Le Page, Gareth; Matthiessen, Peter; Oehlmann, Jörg; Rice, Lynsey; Roberts, Edward; Ruppert, Katharina; Davis, Jessica Elphinstone; Veauvy, Clemence; Weltje, Lennart; Wortham, Ruth; Lagadic, Laurent

    2014-12-01

    The OECD test guideline development program has been extended in 2011 to establish a partial life-cycle protocol for assessing the reproductive toxicity of chemicals to several mollusk species, including the great pond snail Lymnaea stagnalis. In this paper, we summarize the standard draft protocol for a reproduction test with this species, and present inter-comparison results obtained in a 56-day prevalidation ring-test using this protocol. Seven European laboratories performed semi-static tests with cultured snails of the strain Renilys® exposed to nominal concentrations of cadmium chloride (from 53 to 608μgCdL(-1)). Cd concentrations in test solutions were analytically determined to confirm accuracy in the metal exposure concentrations in all laboratories. Physico-chemical and biological validity criteria (namely dissolved oxygen content >60% ASV, water temperature 20±1°C, control snail survival >80% and control snail fecundity >8 egg-masses per snail over the test period) were met in all laboratories which consistently demonstrated the reproductive toxicity of Cd in snails using the proposed draft protocol. Effect concentrations for fecundity after 56days were reproducible between laboratories (68

  13. Anti-inflammatory and protective investigations on the effects of Theranekron® "an alcoholic extract of the Tarantula cubensis" on wound healing of peritoneal in the rat: an in vivo comparative study.

    PubMed

    Adib-Hashemi, Farajollah; Farahmand, Farshad; Hesari, Shamim Fattah; Rezakhaniha, Bijan; Fallah, Ehsan; Fayyaz, Amir Farshid; Dadpay, Masoomeh

    2015-04-02

    The present study sought to investigate the effects of Tarantula cubensis extract (TC; Theranekron®) on the histopathological scores of peritoneal wound healing after laparotomy in the rats. This study was designed to investigate the effects of Theranekron on the peritoneal wound healing after wound creation, on days9, 14, 19, 24 and 29 post-injury in rats. Twenty-four mature Wister-albino male rats were randomly divided into two groups. In the experimental group, TC was repeatedly injected subcutaneously (SC) over the lesion 9, 14,19 and 24 days after laparotomy, whereas the control group received only normal saline by subcutaneous injection and then the animal groups were euthanized9, 14, 19, 24, and 29 days after wounding respectively by intravenous injections of pentobarbital (50 mg/kg). Finally, assessment of the peritoneal wound healing between the groups was carried out by histopathologic data and statistical tests as Mann-Whitney U, Wilcoxon W and Z RESULTS: Histopathological examination indicated significant improvement in angiogenesis, re-epithelialization and less inflammatory response in comparison to control and also, revealed matured, compact and parallel deposition of collagen fibrils on day 29. So, at long term, treatment reduced the inflammation and increased the quality and rate of wound re- epithelialization compared to controls(P < 0.05). Furthermore, excluding the control group, rats exhibited the most pronounced effect on wound closure, with the statistically significant improvement in wound healing being seen at post-operative day 29. Moreover, collagen content on days 24 and 29 in the test group was found to be higher than in the healthy group. To warp up, treated groups had a significant increase in peritoneal wound healing area compared to the control group on all days (P < 0.05). Our results suggested that Theranekron have delivered a novel therapeutic route for wound treatment in clinical practice. The virtual slide(s) for

  14. EFFECTS OF SINGLE, BINARY AND TERTIARY COMBINATIONS WITH Jatropha gossypifolia AND OTHER PLANT-DERIVED MOLLUSCICIDES ON REPRODUCTION AND SURVIVAL OF THE SNAIL Lymnaea acuminata

    PubMed Central

    Yadav, Ram P.; Singh, Ajay

    2014-01-01

    The effect of sub-lethal doses (40% and 80% of LC50/24h) of plant derived molluscicides of singly, binary (1:1) and tertiary (1:1:1) combinations of the Rutin, Ellagic acid, Betulin and taraxerol with J. gossypifolia latex, leaf and stem bark powder extracts and their active component on the reproduction of freshwater snail Lymnaea acuminata have been studied. It was observed that the J. gossypifolia latex, stem bark, individual leaf and their combinations with other plant derived active molluscicidal components caused a significant reduction in fecundity, hatchability and survival of young snails. It is believed that sub-lethal exposure of these molluscicides on snail reproduction is a complex process involving more than one factor in reducing the reproductive capacity. PMID:25229223

  15. Inhibition kinetics of certain enzymes in the nervous tissue of vector snail Lymnaea acuminata by active molluscicidal components of Sapindus mukorossi and Terminalia chebula.

    PubMed

    Upadhyay, Aparna; Singh, Dinesh K

    2011-10-01

    Effect of active molluscicidal components of Sapindus mukorossi and Terminalia chebula on the acetylcholinesterase (AChE), acid and alkaline phosphatase (ACP/ALP) activity in the nervous tissue of freshwater snail Lymnaea acuminata were studied. In vivo and in vitro exposure of saponin (active component of S. mukorossi pericarp) and tannic acid (active component of T. chebula) significantly inhibited the AChE, ACP and ALP activity in the nervous tissue of L. acuminata. The inhibition kinetics of these enzymes indicate that saponin and tannic acid caused competitive and competitive-non-competitive inhibition of AChE, respectively. Saponin also caused competitive and competitive-non-competitive inhibition of ACP and ALP, respectively, whereas tannic acid caused competitive-non-competitive inhibition of ACP and ALP. Thus the inhibition of AChE, ACP and ALP by saponin and tannic acid in the nervous tissue of L. acuminata may be the cause of molluscicidal activity of S. mukorossi and T. chebula.

  16. GABA(A)- and AMPA-like receptors modulate the activity of an identified neuron within the central pattern generator of the pond snail Lymnaea stagnalis.

    PubMed

    Moccia, Francesco; Di Cristo, Carlo; Winlow, William; Di Cosmo, Anna

    2009-03-01

    To examine the neurochemistry underlying the firing of the RPeD1 neuron in the respiratory central pattern generator of the pond snail, Lymnaea stagnalis, we examined electrophysiologically and pharmacologically either "active" or "silent" preparations by intracellular recording and pharmacology. GABA inhibited electrical firing by hyperpolarizing RPeD1, while picrotoxin, an antagonist of GABA(A) receptors, excited silent cells and reversed GABA-induced inhibition. Action potential activity was terminated by 1 mM glutamate (Glu) while silent cells were depolarized by the GluR agonists, AMPA, and NMDA. Kainate exerted a complex triphasic effect on membrane potential. However, only bath application of AMPA desensitized the firing. These data indicate that GABA inhibits RPeD1 via activation of GABA(A) receptors, while Glu stimulates the neuron by activating AMPA-sensitive GluRs.

  17. Effect of binary combination of some plant-derived molluscicides with MGK-264 or piperonyl butoxide on the reproduction of the snail Lymnaea acuminata.

    PubMed

    Singh, Priyamvada; Singh, Vinay K; Singh, Dinesh K

    2005-02-01

    The effects of sub-lethal treatments (20 and 60% of 24-h LC(50)) with plant-derived molluscicides Annona squamosa, acetogenins, Argemone mexicana seed and protopine, in combination (1 + 5) with MGK-264 (ENT 8184) or piperonyl butoxide on the reproduction of Lymnaea acuminata has been studied. The plant-derived molluscicides and their active molluscicidal components, protopine and acetogenins, in combination with ENT 8184 or piperonyl butoxide caused a significant reduction in the fecundity, hatchability and survival of young snails. Combination of A squamosa seed powder with piperonyl butoxide was very effective as it caused a complete arrest of snail fecundity within 24 h of treatment. Removal of the snails to fresh water after the 96-h treatments caused a significant recovery in the fecundity of L acuminata.

  18. Effects of single, binary and tertiary combinations with Jatropha gossypifolia and other plant-derived molluscicides on reproduction and survival of the snail Lymnaea acuminata.

    PubMed

    Yadav, Ram P; Singh, Ajay

    2014-01-01

    The effect of sub-lethal doses (40% and 80% of LC(50)/24h) of plant derived molluscicides of singly, binary (1:1) and tertiary (1:1:1) combinations of the Rutin, Ellagic acid, Betulin and taraxerol with J. gossypifolia latex, leaf and stem bark powder extracts and their active component on the reproduction of freshwater snail Lymnaea acuminata have been studied. It was observed that the J. gossypifolia latex, stem bark, individual leaf and their combinations with other plant derived active molluscicidal components caused a significant reduction in fecundity, hatchability and survival of young snails. It is believed that sub-lethal exposure of these molluscicides on snail reproduction is a complex process involving more than one factor in reducing the reproductive capacity.

  19. Effect of active molluscicidal component of spices on different enzyme activities and biogenic amine levels in the nervous tissue of Lymnaea acuminata.

    PubMed

    Singh, V K; Singh, S; Singh, D K

    1999-12-01

    In vivo exposure of Lymnaea acuminata to thymol and [6]-gingerol (active molluscicidal components of Trachyspermum ammi and Zingiber officinale, respectively) indicates that they significantly alter acetylcholinesterase, lactic dehydrogenase, succinic dehydrogenase and cyto-oxidase activity in the nervous -tissue of snails. In vitro exposure showed that, except for acetylcholinesterase and lactic dehydrogenase, no significant changes were observed in cyto-oxidase and succinic dehydrogenase activity in the nervous tissue of L. acuminata. Sublethal exposure to thymol and [6]-gingerol reduced the levels of 5-hydroxytryptamine (5-HT) and dopamine (DA) in the nervous tissue of L. acuminata. There was, however, no significant change in the level of 5-hydroxy indol acetic acid (5-HIAA). Thymol and [6]-gingerol thus affects all the known neurotransmission mechanisms in the snail either separately or through a complex interaction between the different neurotransmitters. This may account for their toxicity to snails.

  20. Development of a multispecies system for testing reproductive effects on aquatic invertebrates. Experience with Daphnia magna, Chironomus prasinus and Lymnaea peregra.

    PubMed

    Sánchez, Paloma; Tarazona, José V

    2002-10-30

    A cost /effective innovative approach combining three freshwater invertebrates: the cladoceran Daphnia magna, the insect Chironomus prasinus and the basommatophoran snail Lymnaea peregra, in a single system is presented. The selection combines different reproductive strategies: parthenogenesis, sexual reproduction and hermaphroditism, respectively, and covers water column, sediment, food and contact exposure. Results confirm the system's capacity. In 46 days, multi-generation, whole-life-cycle, and chronic reproduction assays can be achieved for D. magna, C. prasinus and L. peregra, respectively. The 21-day D. magna test is commonly used to assess the effects of chemicals on aquatic invertebrates. Wide concerns on its suitability for testing endocrine disrupting chemicals have been raised, particularly for substances with estrogenic activities. The combination of three species with different reproductive strategies offer a suitable approach for assessing ecologically relevant effects related to any mechanism of action, including endocrine disruption.

  1. An interactive map to assess the potential spread of Lymnaea truncatula and the free-living stages of Fasciola hepatica in Switzerland.

    PubMed

    Rapsch, Christina; Dahinden, Tobias; Heinzmann, Dominik; Torgerson, Paul R; Braun, Ueli; Deplazes, Peter; Hurni, Lorenz; Bär, Hansruedi; Knubben-Schweizer, Gabi

    2008-07-04

    The intermediate host of Fasciola hepatica is Lymnaea truncatula in Switzerland. The snail and the free-living stages of the parasite require a moderate climate and moisture for survival, reproduction, and transmission. In Switzerland, these conditions are present in many regions, resulting in a mean prevalence of bovine fasciolosis from 8.4 to 21.4%. An interactive map was created in order to demonstrate the relative risk of transmission by modelling the environmental conditions that promote the survival and reproduction of the larval stages of the parasite and the parasite's intermediate host. The map is based on temperature and rainfall data, soil conditions including ground water and forest cover in Switzerland. Extensive information on the free-living stages of F. hepatica and the intermediate host L. truncatula and how the development of these are affected by these environmental factors was used to create the interactive risk map.

  2. DNA multigene characterization of Fasciola hepatica and Lymnaea neotropica and its fascioliasis transmission capacity in Uruguay, with historical correlation, human report review and infection risk analysis.

    PubMed

    Bargues, María Dolores; Gayo, Valeria; Sanchis, Jaime; Artigas, Patricio; Khoubbane, Messaoud; Birriel, Soledad; Mas-Coma, Santiago

    2017-02-01

    Fascioliasis is a pathogenic disease transmitted by lymnaeid snails and recently emerging in humans, in part due to effects of climate changes, anthropogenic environment modifications, import/export and movements of livestock. South America is the continent presenting more human fascioliasis hyperendemic areas and the highest prevalences and intensities known. These scenarios appear mainly linked to altitude areas in Andean countries, whereas lowland areas of non-Andean countries, such as Uruguay, only show sporadic human cases or outbreaks. A study including DNA marker sequencing of fasciolids and lymnaeids, an experimental study of the life cycle in Uruguay, and a review of human fascioliasis in Uruguay, are performed. The characterization of Fasciola hepatica from cattle and horses of Uruguay included the complete sequences of the ribosomal DNA ITS-2 and ITS-1 and mitochondrial DNA cox1 and nad1. ITS-2, ITS-1, partial cox1 and rDNA 16S gene of mtDNA were used for lymnaeids. Results indicated that vectors belong to Lymnaea neotropica instead of to Lymnaea viator, as always reported from Uruguay. The life cycle and transmission features of F. hepatica by L. neotropica of Uruguay were studied under standardized experimental conditions to enable a comparison with the transmission capacity of F. hepatica by Galba truncatula at very high altitude in Bolivia. On this baseline, we reviewed the 95 human fascioliasis cases reported in Uruguay and analyzed the risk of human infection in front of future climate change estimations. The correlation of fasciolid and lymnaeid haplotypes with historical data on the introduction and spread of livestock into Uruguay allowed to understand the molecular diversity detected. Although Uruguayan L. neotropica is a highly efficient vector, its transmission capacity is markedly lower than that of Bolivian G. truncatula. This allows to understand the transmission and epidemiological differences between Andean highlands and non

  3. Pyrosequencing-based transcriptomic resources in the pond snail Lymnaea stagnalis, with a focus on genes involved in molecular response to diquat-induced stress.

    PubMed

    Bouétard, Anthony; Noirot, Céline; Besnard, Anne-Laure; Bouchez, Olivier; Choisne, Damien; Robe, Eugénie; Klopp, Christophe; Lagadic, Laurent; Coutellec, Marie-Agnès

    2012-11-01

    Due to their ability to explore whole genome response to drugs and stressors, omics-based approaches are widely used in toxicology and ecotoxicology, and identified as powerful tools for future ecological risk assessment and environmental monitoring programs. Understanding the long-term effects of contaminants may indeed benefit from the coupling of genomics and eco-evolutionary hypotheses. Next-generation sequencing provides a new way to investigate pollutants impact, by targeting early responses, screening chemicals, and directly quantifying gene expression, even in organisms without reference genome. Lymnaea stagnalis is a freshwater mollusk in which access to genomic resources is critical for many scientific issues, especially in ecotoxicology. We used 454-pyrosequencing to obtain new transcriptomic resources in L. stagnalis and to preliminarily explore gene expression response to a redox-cycling pesticide, diquat. We obtained 151,967 and 128,945 high-quality reads from control and diquat-exposed individuals, respectively. Sequence assembly provided 141,999 contigs, of which 124,387 were singletons. BlastX search revealed significant match for 34.6 % of the contigs (21.2 % protein hits). KEGG annotation showed a predominance of hits with genes involved in energy metabolism and circulatory system, and revealed more than 400 putative genes involved in oxidative stress, cellular/molecular stress and signaling pathways, apoptosis, and metabolism of xenobiotics. Results also suggest that diquat may have a great diversity of molecular effects. Moreover, new genetic markers (putative SNPs) were discovered. We also created a Ensembl-like web-tool for data-mining ( http://genotoul-contigbrowser.toulouse.inra.fr:9095/Lymnaea_stagnalis/index.html ). This resource is expected to be relevant for any genomic approach aimed at understanding the molecular basis of physiological and evolutionary responses to environmental stress in L. stagnalis.

  4. [Lymnaea cousini , intermediate host of Fasciola hepatica in the Colombian high tropical Andes, and its new haplotypes confirmed with the mitochondrial marker cytochrome oxidase I].

    PubMed

    Uribe, Nelson; Becerra, Wlda Margarita; Velásquez, Luz Elena

    2014-01-01

    Fasciolosis is the disease transmitted by vectors with the highest latitudinal, longitudinal, and altitudinal distribution due to the colonizing capacity of the parasite Fasciola hepatica and its intermediate hosts, Lymnaeidae mollusks. These snails are under research due to their epidemiological importance, but their taxonomic identification is difficult given their interspecific phenotypical similarity. For this reason, there is uncertainty regarding Lymnaea cousini -a host of F. hepatica in Colombia- due to the morphological similarity it has with Lymnaea meridensis , recently described for Venezuela. To confirm with the COI marker (ADNmt) the taxonomic status of individuals morphologically identified as L. cousini from Nariño, Norte de Santander, and Santander (Colombia), deposited in the Vector Mollusks Collection VHET No. 37 of Universidad de Antioquia. The amplification of the mitochondrial COI required total DNA extraction of each individual´s foot using the DNeasy Blood and Tissue Kit (Qiagen®). Products amplified were sent for sequencing to Macrogen Inc., Korea. Twenty seven sequences generated in this research were compared to sequences published in the GenBank, including sequences of the type locality of L. cousini . Two new haplotypes of L. cousini were obtained for Colombia. Specimens from Nariño correspond to haplotype A, referenced for Ecuador, and specimens from Santander and Norte de Santander belong to a new haplotype we called haplotype D. By using the mitochondrial COI marker, we confirmed that the species under study did correspond to L. cousini . The number of known haplotypes of the species for Colombia has been duplicated and its geographical distribution has been extended to the southwest and northeast of the Colombian high Andean region.

  5. DNA multigene characterization of Fasciola hepatica and Lymnaea neotropica and its fascioliasis transmission capacity in Uruguay, with historical correlation, human report review and infection risk analysis

    PubMed Central

    Gayo, Valeria; Sanchis, Jaime; Artigas, Patricio; Khoubbane, Messaoud; Birriel, Soledad; Mas-Coma, Santiago

    2017-01-01

    Background Fascioliasis is a pathogenic disease transmitted by lymnaeid snails and recently emerging in humans, in part due to effects of climate changes, anthropogenic environment modifications, import/export and movements of livestock. South America is the continent presenting more human fascioliasis hyperendemic areas and the highest prevalences and intensities known. These scenarios appear mainly linked to altitude areas in Andean countries, whereas lowland areas of non-Andean countries, such as Uruguay, only show sporadic human cases or outbreaks. A study including DNA marker sequencing of fasciolids and lymnaeids, an experimental study of the life cycle in Uruguay, and a review of human fascioliasis in Uruguay, are performed. Methodology/Principal findings The characterization of Fasciola hepatica from cattle and horses of Uruguay included the complete sequences of the ribosomal DNA ITS-2 and ITS-1 and mitochondrial DNA cox1 and nad1. ITS-2, ITS-1, partial cox1 and rDNA 16S gene of mtDNA were used for lymnaeids. Results indicated that vectors belong to Lymnaea neotropica instead of to Lymnaea viator, as always reported from Uruguay. The life cycle and transmission features of F. hepatica by L. neotropica of Uruguay were studied under standardized experimental conditions to enable a comparison with the transmission capacity of F. hepatica by Galba truncatula at very high altitude in Bolivia. On this baseline, we reviewed the 95 human fascioliasis cases reported in Uruguay and analyzed the risk of human infection in front of future climate change estimations. Conclusions/Significance The correlation of fasciolid and lymnaeid haplotypes with historical data on the introduction and spread of livestock into Uruguay allowed to understand the molecular diversity detected. Although Uruguayan L. neotropica is a highly efficient vector, its transmission capacity is markedly lower than that of Bolivian G. truncatula. This allows to understand the transmission and

  6. DNA sequence characterisation and phylogeography of Lymnaea cousini and related species, vectors of fascioliasis in northern Andean countries, with description of L. meridensis n. sp. (Gastropoda: Lymnaeidae).

    PubMed

    Bargues, M Dolores; Artigas, Patricio; Khoubbane, Messaoud; Mas-Coma, Santiago

    2011-07-12

    Livestock fascioliasis is a problem throughout Ecuador, Colombia and Venezuela, mainly in Andean areas where the disease also appears to affect humans. Transmission patterns and epidemiological scenarios of liver fluke infection have shown to differ according to the lymnaeid vector snail species involved. These Andean countries present the vectors Lymnaea cousini, L. bogotensis and L. ubaquensis, unknown in the rest of Latin America. An exhaustive combined haplotype study of these species is performed by means of DNA sequencing of the nuclear ribosomal 18S RNA gene, ITS-2 and ITS-1, and mitochondrial DNA cox1 gene. The conserved 5.8S rDNA sequence corroborated that no pseudogenes are involved in the numerous non-microsatellite/minisatellite-related indels appearing between the ITS-2 and ITS-1 sequences when comparing different L. cousini--L. bogotensis populations. Sequence analyses and phylogenetic reconstruction methods including other lymnaeid vector species show that (i) L. bogotensis is a synonym of L. cousini, (ii) L. ubaquensis is a synonym of Pseudosuccinea columella, and (iii) populations of L. cousini hitherto known from Venezuelan highlands indeed belong to a new species for which the name L. meridensis n. sp. is proposed. This new species is described and a complete phenotypic differentiation provided. ITS-2, ITS-1 and cox1 prove to be good markers for specimen classification and haplotype characterisation of these morphologically similar lymnaeids in endemic areas. Analysis of the 18S gene and phylogenetic reconstructions indicate that L. cousini and L. meridensis n. sp. cluster in an evolutionary line different from the one of P. columella, despite their external resemblance. This suggests an evolutionary phenotypic convergence related to similar environments and which has given rise to frequent specimen misclassification. Body size and phylogenetic relationships of L. meridensis n. sp. with well-known vectors as Lymnaea cousini and P. columella, as

  7. DNA sequence characterisation and phylogeography of Lymnaea cousini and related species, vectors of fascioliasis in northern Andean countries, with description of L. meridensis n. sp. (Gastropoda: Lymnaeidae)

    PubMed Central

    2011-01-01

    Background Livestock fascioliasis is a problem throughout Ecuador, Colombia and Venezuela, mainly in Andean areas where the disease also appears to affect humans. Transmission patterns and epidemiological scenarios of liver fluke infection have shown to differ according to the lymnaeid vector snail species involved. These Andean countries present the vectors Lymnaea cousini, L. bogotensis and L. ubaquensis, unknown in the rest of Latin America. An exhaustive combined haplotype study of these species is performed by means of DNA sequencing of the nuclear ribosomal 18S RNA gene, ITS-2 and ITS-1, and mitochondrial DNA cox1 gene. Results The conserved 5.8S rDNA sequence corroborated that no pseudogenes are involved in the numerous non-microsatellite/minisatellite-related indels appearing between the ITS-2 and ITS-1 sequences when comparing different L. cousini - L. bogotensis populations. Sequence analyses and phylogenetic reconstruction methods including other lymnaeid vector species show that (i) L. bogotensis is a synonym of L. cousini, (ii) L. ubaquensis is a synonym of Pseudosuccinea columella, and (iii) populations of L. cousini hitherto known from Venezuelan highlands indeed belong to a new species for which the name L. meridensis n. sp. is proposed. This new species is described and a complete phenotypic differentiation provided. Conclusions ITS-2, ITS-1 and cox1 prove to be good markers for specimen classification and haplotype characterisation of these morphologically similar lymnaeids in endemic areas. Analysis of the 18S gene and phylogenetic reconstructions indicate that L. cousini and L. meridensis n. sp. cluster in an evolutionary line different from the one of P. columella, despite their external resemblance. This suggests an evolutionary phenotypic convergence related to similar environments and which has given rise to frequent specimen misclassification. Body size and phylogenetic relationships of L. meridensis n. sp. with well-known vectors as

  8. The role of spatial and temporal heterogeneity and competition in structuring trematode communities in the great pond snail, Lymnaea stagnalis (L.)

    USGS Publications Warehouse

    Soldánová, Miroslava; Kuris, Armand M.; Scholz, Tomáš; Lafferty, Kevin D.

    2012-01-01

    We assessed how spatial and temporal heterogeneity and competition structure larval trematode communities in the pulmonate snail Lymnaea stagnalis. To postulate a dominance hierarchy, mark-release-recapture was used to monitor replacements of trematode species within snails over time. In addition, we sampled the trematode community in snails in different ponds in 3 consecutive years. A total of 7,623 snails (10,382 capture events) was sampled in 7 fishponds in the Jindřichův Hradec and Třeboň areas in South Bohemia (Czech Republic) from August 2006 to October 2008. Overall, 39% of snails were infected by a community of 14 trematode species; 7% of snails were infected with more than 1 trematode species (constituting 16 double- and 4 triple-species combinations). Results of the null-model analyses suggested that spatial heterogeneity in recruitment among ponds isolated trematode species from each other, whereas seasonal pulses in recruitment increased species interactions in some ponds. Competitive exclusion among trematodes led to a rarity of multiple infections compared to null-model expectations. Competitive relationships among trematode species were hypothesized as a dominance hierarchy based on direct evidence of replacement and invasion and on indirect evidence. Seven top dominant species with putatively similar competitive abilities (6 rediae and 1 sporocyst species) reduced the prevalence of the other trematode species developing in sporocysts only.

  9. Molluscicidal potential of Heterorhabditis baujardi (Rhabditida: Heterorhabditidae), strain LPP7, on Lymnaea columella (Gastropoda: Pulmonata): An alternative for biological control of fasciolosis.

    PubMed

    Tunholi, Victor Menezes; Lorenzoni, P O; da Silva, Ygor Henrique; Tunholi-Alves, Vinícius Menezes; Boeloni, Jankerle Neves; da Silva, Maria Aparecida; Monteiro, Caio Oliveira; Prata, M C A; Pinheiro, J; Martins, Isabella Vilhena Freire

    2017-09-01

    This study elucidated for the first time, under laboratory conditions, the susceptibility of Lymnaea columella to infective juveniles of Heterorhabditis baujardi LPP7. Exposure to the nematodes induced an average mortality rate of 66.66% in the population of L. columella, with the highest values attained from the second week after exposure onward. In addition, all the reproductive parameters analyzed (total number of eggs, number of egg masses, number of eggs laid/snail, embryo hatching rate and content of galactogen stored in the albumen gland) changed as a result of the infection. The results indicate the occurrence of the phenomenon of parasitic castration in L. columella infected by H. baujardi LPP7, probably through depletion of energy reserves such as galactogen, necessary to meet the intense metabolic demands of the nematode's larval stages. Finally, histopathological analysis demonstrated an intense process of cell disorganization, characterized by the occurrence of granulomatous inflammatory reactions in tissues of exposed snails, induced by the spoliative action of the bacteria/nematode. The results suggest the use of H. baujardi LPP7 as an alternative for biological control of the population of this intermediate host, and thus of the diseases in whose epidemiological chain it participates, especially fasciolosis, in line with the recommendations of the World Health Organization (WHO). Copyright © 2017. Published by Elsevier B.V.

  10. Temporal variation in prevalence and abundance of metacercariae in the pulmonate snail Lymnaea stagnalis in Chany Lake, West Siberia, Russia: long-term patterns and environmental covariates.

    PubMed

    Yurlova, Natalia I; Vodyanitskaya, Svetlana N; Serbina, Elena A; Biserkov, Valko Y; Georgiev, Boyko B; Chipev, Nesho H

    2006-04-01

    Infrapopulations of trematode metacercariae were monitored in the snail Lymnaea stagnalis over 17 yr (1982-1999) at Chany Lake, Novosibirskaya Oblast', Russia. Eighteen trematode species were recorded. Patterns of occurrence varied from 4 species (Echinoparyphium aconiatum, Echinoparyphium recurvatum, Moliniella anceps, and Cotylurus cornutus) that persisted at relatively high prevalence (> 60% of samples) across sites, seasons, and years, to species that were very rare and sporadic in occurrence. The stability of the 4 common species was probably because of their occurrence either in a wide range of definitive hosts or in a host adapted to the extreme abiotic changes that occurred from year to year in these wetlands. The prevalence and mean abundance of C. cornutus were negatively correlated with water level in the wetlands; its prevalence was also correlated with water temperature. The mean abundance of M. anceps was positively correlated with water level. The most probable explanation for the cyclic dynamics of infections of the common species is change in population sizes and densities of definitive and intermediate hosts, which mediated cyclic alterations in water levels.

  11. Bioaccumulation and toxic effects of cadmium on feeding and growth of an Indian pond snail Lymnaea luteola L. under laboratory conditions.

    PubMed

    Das, Sangita; Khangarot, B S

    2010-10-15

    Effects of dissolved cadmium exposure on the survival, feeding, growth rates and accumulation in Indian pond snails Lymnaea luteola L. were examined for a period of 7 weeks. The concentrations of cadmium tested were 0, 10, 32, 100, 320, 560, and 1000 microg l(-1). Cadmium exposure significantly inhibited the feeding and growth rates. At higher Cd concentrations snails refused to consume food offered as plant Marsilia sp. leaves. Cadmium mainly accumulated in soft tissues in a dose-dependent manner. After 4 and 7 weeks of exposure, the no observed effect concentration (NOEC) of Cd was 10 microg l(-1) and the lowest observed effect concentration (LOEC) was 32 microg l(-1). Reduction of growth (decrease in wet weight) was noticed followed by a high mortality in higher Cd concentrations. Significant reduction in food consumption and growth rates was found at 32 microg l(-1) and above Cd concentration. A significant relationship between Cd exposure and growth and feeding rates was noticed. The results obtained with these key aquatic organisms in the food chains complement those obtained with other aquatic organisms and gastropod snails. The findings of the present study and those of earlier studies suggested that Indian pond snail L. luteola are useful test organisms for ecotoxicology bioassays. 2010 Elsevier B.V. All rights reserved.

  12. Considerations for test design to accommodate energy-budget models in ecotoxicology: a case study for acetone in the pond snail Lymnaea stagnalis.

    PubMed

    Barsi, Alpar; Jager, Tjalling; Collinet, Marc; Lagadic, Laurent; Ducrot, Virginie

    2014-07-01

    Toxicokinetic-toxicodynamic (TKTD) modeling offers many advantages in the analysis of ecotoxicity test data. Calibration of TKTD models, however, places different demands on test design compared with classical concentration-response approaches. In the present study, useful complementary information is provided regarding test design for TKTD modeling. A case study is presented for the pond snail Lymnaea stagnalis exposed to the narcotic compound acetone, in which the data on all endpoints were analyzed together using a relatively simple TKTD model called DEBkiss. Furthermore, the influence of the data used for calibration on accuracy and precision of model parameters is discussed. The DEBkiss model described toxic effects on survival, growth, and reproduction over time well, within a single integrated analysis. Regarding the parameter estimates (e.g., no-effect concentration), precision rather than accuracy was affected depending on which data set was used for model calibration. In addition, the present study shows that the intrinsic sensitivity of snails to acetone stays the same across different life stages, including the embryonic stage. In fact, the data on egg development allowed for selection of a unique metabolic mode of action for the toxicant. Practical and theoretical considerations for test design to accommodate TKTD modeling are discussed in the hope that this information will aid other researchers to make the best possible use of their test animals. © 2014 SETAC.

  13. Evolutionary conservation of the insulin gene structure in invertebrates: cloning of the gene encoding molluscan insulin-related peptide III from Lymnaea stagnalis.

    PubMed

    Smit, A B; van Marle, A; van Elk, R; Bogerd, J; van Heerikhuizen, H; Geraerts, W P

    1993-08-01

    Although insulins and structurally related peptides are found in vertebrates as well as in invertebrates, it is not clear whether the genes encoding these hormones have emerged from a single ancestral (insulin)-type of gene or, alternatively, have arisen independently through convergent evolution from different types of gene. To investigate this issue, we cloned the gene encoding the molluscan insulin-related peptide III (MIP III) from the freshwater snail, Lymnaea stagnalis. The predicted MIP III preprohormone had the overall organization of preproinsulin, with a signal peptide and A and B chains, connected by two putative C peptides. Although MIP III was found to share key features with vertebrate insulins, it also had unique structural characteristics in common with the previously identified MIPs I and II, thus forming a distinct class of MIP peptides within the insulin superfamily. MIP III is synthesized in neurones in the brain. It is encoded by a gene with the overall organization of the vertebrate insulin genes, with three exons and two introns, of which the second intron interrupts the coding region of the C peptides. Our data therefore demonstrate that in the Archaemetazoa, the common ancestor of the vertebrates and invertebrates, a primordial peptide with a two-chain insulin configuration encoded by a primordial insulin-type gene must have been present.

  14. Effects of in vitro and in vivo lead exposure on voltage-dependent calcium channels in central neurons of Lymnaea stagnalis.

    PubMed

    Audesirk, G

    1987-01-01

    Currents through calcium channels of members of an identified cluster of neurons (B cells) in the pond snail Lymnaea stagnalis were studied under voltage clamp. The normal physiological saline was modified to maximize the visibility of voltage-dependent calcium currents and minimize contamination by other currents. Barium was used as the charge carrier for the calcium channels. Depolarizing voltage steps induce an inward current, the magnitude of which varies with the barium concentration. In brains taken from animals not exposed in vivo to lead, in vitro addition of lead acetate to the recording medium (0.25 to 14 microM) inhibits the barium current by 59 +/- 14% (mean +/- s.d.), in a manner that is independent of the lead concentration. The magnitude of the residual current still varies with the barium concentration. The voltage dependence of the current appears to be unaffected by lead. In contrast to some other calcium-channel blockers, such as cobalt, the inhibition of barium currents by in vitro lead exposure is irreversible, at least in short-term experiments. Contrary to expectations based on these in vitro results, barium currents in B cells of animals exposed to 5 microM lead for 6 to 12 weeks in vivo were approximately twice as large as barium currents in B cells from unexposed controls, when both were recorded in lead-free saline. It is possible that chronic in vivo lead exposure causes an increase in the number of calcium channels in these neurons.

  15. The population density of Lymnaea columella (Say, 1817) (Mollusca, Lymnaeidae) an intermediate host of Fasciola hepatica (Linnaeus, 1758), in the Caparaó microregion, ES, Brazil.

    PubMed

    D'Almeida, S C G; Freitas, D F; Carneiro, M B; Camargo, P F; Azevedo, J C; Martins, I V F

    2016-06-01

    The aim of this study was to monitor the population density of Lymnaea columella, an intermediate host of Fasciola hepatica, in various aquatic habitats and in drinking water in the area of the Instituto Federal de Educação, Ciência e Tecnologia do Espírito Santo, on Caparaó Microregion, municipality of Alegre, state of Espírito Santo, Brazil. Monthly samplings were performed at certain points between drainage areas and drinking water in cattle and goat production systems during the years 2010 to 2013. The mean temperature, precipitation and the frequency of samples of L. columella were analysed graphically according the monthly average during the study period. A total of 2,038 molluscs were collected, 1558 of which were L. columella, that predominated in all sampled points. The highest average of specimens observed for L. columella was in the years 2010 and 2013 (51.0), and occurred decreased in 2011 (19.8). The temperature and precipitation averaged is 23.7 °C and 141 mm/year, respectively. Rainfall peak occurred in March (2011, 2013) and November (2012), during these periods the population of L. columella growth. There was no significant difference in the relationship between the specimens observed with seasons (dry-wet), thus the population of L. columella remained stable and can be found throughout the year.

  16. Accumulation of free and covalently bound microcystins in tissues of Lymnaea stagnalis (Gastropoda) following toxic cyanobacteria or dissolved microcystin-LR exposure.

    PubMed

    Lance, Emilie; Neffling, Milla-Riina; Gérard, Claudia; Meriluoto, Jussi; Bormans, Myriam

    2010-03-01

    Accumulation of free microcystins (MCs) in freshwater gastropods has been demonstrated but accumulation of MCs covalently bound to tissues has never been considered so far. Here, we follow the accumulation of total (free and bound) MCs in Lymnaea stagnalis exposed to i) dissolved MC-LR (33 and 100 microg L(-1)) and ii) Planktothrix agardhii suspensions producing 5 and 33 microg MC-LR equivalents L(-1) over a 5-week period, and after a 3-week depuration period. Snails exposed to dissolved MC-LR accumulated up to 0.26 microg total MCs g(-1) dry weight (DW), with no detection of bound MCs. Snails exposed to MCs producing P. agardhii accumulated up to 69.9 microg total MCs g(-1) DW, of which from 17.7 to 66.7% were bound. After depuration, up to 15.3 microg g(-1) DW of bound MCs were detected in snails previously exposed to toxic cyanobacteria, representing a potential source of MCs transfer through the food web. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  17. Effect of the photoperiod on the time schedule of egg mass production in Lymnaea stagnalis, as induced by ovulation hormone injections.

    PubMed

    Dogterom, G E; Bohlken, S; Joosse, J

    1983-02-01

    In the pulmonate snail Lymnaea stagnalis the neurosecretory caudo-dorsal cells (CDC) produce an ovulation hormone (CDCH) which is released at the periphery of the cerebral commissure (COM). Time schedules of the successive stages of the egg mass production following CDCH injection (COM extract) were determined at 20 degrees. Ovulation is performed rapidly, within 10 to 20 min. The latencies of the other stages are: egg formation, 20-30 min; egg mass formation, 60-90 min; and oviposition, about 120 min. The duration of oviposition is dependent on the size of the egg mass and varies from 5 to 20 min. At a 16-hr photoperiod all stages start 10 min earlier than at a 12-hr photoperiod. It is suggested that the effect of the photoperiod is achieved by a change of release activities of dorsal bodies and/or of CDC. The possibility that a nervous mechanism is involved in the control of the packaging of the egg cells is discussed.

  18. Chlorophyllin Bait Formulation and Exposure to Different Spectrum of Visible Light on the Reproduction of Infected/Uninfected Snail Lymnaea acuminata.

    PubMed

    Kumar, Navneet; Singh, D K; Singh, Vinay Kumar

    2016-01-01

    Fasciolosis is a waterborne disease, caused by Fasciola species. Snail Lymnaea acuminata is an intermediate host of these flukes. Control of snail population is major tool in reducing the incidences. Variation in light intensity and wavelength caused significant changes in reproduction pattern of snails. Maximum fecundity was noted with bait containing carbohydrate (starch, 468 ± 0.10/20 snails) or amino acid (serine, 319 ± 0.29/20 snails) as attractant. Sublethal feeding of chlorophyllin bait with starch or serine attractant to infected and uninfected snails caused significant reduction in fecundity, hatchability, and survivability. These significant changes are observed in snails exposed to different spectral band of visible light and sunlight. Maximum fecundity of 536 ± 2.0 and minimum of 89.3 ± 0.4 were noted in snails not fed with bait and exposed to sunlight and red spectral band, respectively. There was complete arrest in the fecundity of infected and uninfected snails and no survivability of uninfected snails after 48 h feeding with bait containing chlorophyllin + attractant. Minimum hatchability (9.25 ± 0.5) was noted in red light exposed, chlorophyllin + starch fed infected snails and hatching period of bait fed snails was prolonged. Conclusively, chlorophyllin bait and red light reduce reproduction capacity in snails.

  19. Schistosomin: a pronase-sensitive agent in the hemolymph of Trichobilharzia ocellata-infected Lymnaea stagnalis inhibits the activity of albumen glands in vitro.

    PubMed

    Joosse, J; van Elk, R; Mosselman, S; Wortelboer, H; van Diepen, J C

    1988-01-01

    The schistosome parasite, Trichobilharzia ocellata, nearly completely inhibits the reproductive activity of its intermediate host, Lymnaea stagnalis. The synthetic activity of albumen glands of infected snails at day 35 postinfection (p.i.) is only 1% of the control value. The parasite acts by humoral means. We tested the hypothesis that (a) specific humoral agent(s) is (are) involved and refer to this (these) agent(s) as schistosomin. The presence of schistosomin in the hemolymph of infected snails was investigated by using galactogen synthesis in albumen glands as an in vitro bioassay. The synthetic activity of albumen glands of noninfected snails decreased by about 50% during a 1-h incubation in the hemolymph of infected snails. This inhibition is attributed to schistosomin. Based on these results, with the present bioassay schistosomin appears in the hemolymph between days 28-36 p.i. onwards. Schistosomin is heat-stable (100 degrees C) and pronase-sensitive, and therefore it might have a peptide nature. Schistosomin suppresses the stimulating action of the female, gonadotrophic dorsal body hormone at relatively low doses, which suggests that it may compete with this hormone for the same receptors. The development of two other bioassays for schistosomin in our laboratory is discussed.

  20. Immune responses in the aquatic gastropod Lymnaea stagnalis under short-term exposure to pharmaceuticals of concern for immune systems: Diclofenac, cyclophosphamide and cyclosporine A.

    PubMed

    Boisseaux, P; Noury, P; Thomas, H; Garric, J

    2017-05-01

    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. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Acquisition of Ca2+ and HCO3−/CO32− for shell formation in embryos of the common pond snail Lymnaea stagnalis

    PubMed Central

    O’Donnell, Michael J.; Grosell, Martin

    2010-01-01

    Embryos of the freshwater common pond snail Lymnaea stagnalis develop to hatch within 10 days under control conditions (22°C, Miami-Dade tap water) and this development is impaired by removal of ambient calcium. In contrast, embryos did not exhibit dependence upon an ambient HCO3−/CO32− source, developing and hatching in HCO3−/CO32−-free water at rates comparable to controls. Post-metamorphic, shell-laying embryos exhibited a significant saturation-type calcium uptake as a function of increasing ambient calcium concentration. However, changes in ambient bicarbonate concentration did not influence calcium or apparent titratable alkalinity uptake. There was a distinct shift from no significant flux in pre-metamorphic embryos to net uptake of calcium in post-metamorphic stages as indicated by an increased uptake from the micro-environment surrounding the egg mass and increased net uptake in 24-h, whole egg mass flux measurements. Furthermore, HCO3−/CO32− acquisition as measured by titratable alkalinity flux is at least partially attributable to an endogenous carbonate source that is associated with acid extrusion. Thus, calcium requirements for embryonic shell formation are met via uptake but HCO3−/CO32−, which is also necessary for shell formation is acquired in part from endogenous sources with no detectable correlation to ambient HCO3−/CO32− availability. PMID:20361194

  2. A comparison of metal levels and antioxidant enzymes in freshwater snails, Lymnaea natalensis, exposed to sediment and water collected from Wright Dam and Lower Mguza Dam, Bulawayo, Zimbabwe.

    PubMed

    Siwela, A H; Nyathi, C B; Naik, Y S

    2010-10-01

    We compared the bioaccumulation of lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu), nickel (Ni) and iron (Fe) with antioxidant enzyme activity in tissues of the snails, Lymnaea natalensis, exposed to elements of two differently polluted dams. 45 snails were exposed to sediment and water collected from Wight Dam (reference) whilst another 45 snails were also exposed to sediment and water collected from Lower Mguza Dam (polluted dam). Except for Fe in sediment and Pb in water, metal concentrations were statistically higher in sediment and water collected from Lower Mguza Dam. Lead, Cd and Zn were two times higher in tissues of snails exposed to Lower Mguza Dam elements. On one hand, superoxide dismutase (SOD), diphosphotriphosphodiaphorase (DTD) and catalase (CAT) activities were significantly lower whilst malondialdehyde (MDA) levels were significantly higher in tissues of snails exposed to Lower Mguza Dam sediment and water. On the other hand, selenium-dependent glutathione peroxidase (Se-GPX) activity was significantly elevated in tissues of snails exposed to Lower Mguza Dam sediment and water. Snails exposed to Lower Mguza Dam elements seem to have responded to pollution by increasing CAT and Se-GPX specific activity in an effort to detoxify peroxides produced as a result of metal induced oxidative stress.

  3. Comparative horizontal starch gel isoenzyme electrophoresis of Lymnaea (Bullastra) cumingiana (Pulmonata: Lymnaeidae) and related taxa in the Indo-Pacific region.

    PubMed

    Monzon, R B; Thammapalerd, N; Kitikoon, V; Temcharoen, P; Sornmani, S; Viyanant, V

    1994-03-01

    Foot muscle tissue extracts from six lymnaeid species of the Indo-Pacific region [Lymnaea (Bullastra) cumingiana and L. (Radix) quadrasi from the Philippines, L. (R.) rubiginosa from Indonesia and Thailand, and L. (R.) viridis from Guam and Hong Kong] were subjected to horizontal starch gel isoenzyme electrophoresis and assayed for seven isoenzymes (AcP, AlP, CA, EST, LAP, CAT and GOT) to elucidate their taxonomic relationships. L. cumingiana exhibited banding patterns for EST, LAP and CAT uniquely different from the rest, thus supporting the hypothesis that it is a distinct species. Zymogram patterns for AlP, CA, EST and LAP attest to the close affinity between L. quadrasi and L. rubiginosa (Indonesia and Thailand). Minor differences suggest a closer relationship between the two geographical strains of L. rubiginosa than with L. quadrasi, lending support to the hypothesis that L. quadrasi is inseparable as a race or variety from the typical L. swinhoei Adams, which in turn is but a race of L. auricularia, which also encompasses L. rubiginosa. The two geographical strains of L. viridis from Guam and Hong Kong showed the greatest consistency with regards to similarity and congruence in banding patterns. Non-specific esterases (EST) were the most useful in distinguishing the six species from each other.

  4. Extremely low frequency magnetic field and the hatching rate of Fasciola hepatica eggs, the fecundity and survival of liver fluke-infected snail, Lymnaea truncatula.

    PubMed

    Kołodziejczyk, Lidia; Kuźna-Grygiel, Wanda; Gonet, Bolesław; Podraza, Wojciech

    2010-01-01

    Eggs of Fasciola hepatica were exposed for 10 days to extremely low frequency magnetic field (ELFMF) at the frequency of 50 Hz and density of 2 mT (rms). The results show an accelerated hatching of F. hepatica eggs in relation to control (non-exposed) group. The host snails, Lymnaea truncatula, were divided into three groups; those of groups I and II were infected with the miracidia of F. hepatica hatched from control egg culture, whereas those of group III were infected with miracidia hatched from eggs affected by ELFMF. Thereafter, snails of groups II and III were exposed to ELFMF for 53 days, whereas those of group I were not exposed. At day 14 post infection, a significant decrease was observed in the number of cocoons laid by snails of group III, compared with control. Also, significant mortality in group III snails was observed 42 days post infection. The increased mortality and a lower number of cocoons laid by group III snails have probably resulted from enhanced stimulation of metacercarial parthenogenetic reproduction in consequence of infecting the molluscs with miracidia reared under ELFMF.

  5. Isolation and detection of Fasciola hepatica DNA in Lymnaea viatrix from formalin-fixed and paraffin-embedded tissues through multiplex-PCR.

    PubMed

    Magalhães, Kelly Grace; Jannotti-Passos, Liana K; Caldeira, Roberta L; Berne, Maria Elisabeth Aires; Muller, Gertrude; Carvalho, Omar S; Lenzi, Henrique Leonel

    2008-04-15

    Detection of Fasciola hepatica infection in Lymnaea viatrix through analysis of histological cuts is based upon morphological characters of the parasite during the intra-mollusk phase of parasitism. At this stage, trematode forms are very similar and, thus, very difficult to differentiate. Specific detection may also be impaired by the presence of other helminthes in the mollusk. Histological samples are usually fixed in formalin, embedded in paraffin, sectioned and HE stained. In the current study, a method for the extraction of DNA from formalin-fixed, paraffin-embedded tissues was standardized by means of deparaffinizing with xylol and digesting with proteinase K. Extracted DNA was amplified in a multiplex-PCR, by using simultaneous primers in a single reaction under high stringency conditions. Results showed specific amplification of DNA from the trematode and the snails. The technique was sensitive enough to detect F. hepatica infections in L. viatrix, in histological sections in which the presence of larval stages could not be observed through brightfield microscopy. The profiles generated were: stair bands referring to F. hepatica DNAmt amplification; a band of 1200 bp referring to L. viatrix ITS and another of 1300 bp referring to F. hepatica ITS and other trematodes. Multiplex-PCR has shown to be a fast, safe, highly sensitive and specific method, which is able to amplify DNA from fixed tissues, despite a low DNA quantity and its degradation caused by fixation processes. Such methodology may be useful in studies on fascioliasis epidemiology, enabling the use of material from histological collections.

  6. PCR-RFLP Analysis of 28 SrDNA for Specification of Fasciola gigantica (Cobbold, 1855) in the Infected Lymnaea auricularia (Linnaeus, 1785) Snails from Northwestern Iran.

    PubMed

    Yakhchali, Mohammad; Malekzadeh-Viayeh, Reza; Imani-Baran, Abass

    2014-09-01

    Fasciolosis in livestock is a crucial concern in the globe, mainly due to its impact on human health. The aim of this study was to determine the rate of infection with Fasciola gigantica (Cobbold, 1855) larvae in the field-collected snails of Lymnaea auricularia (Linnaeus, 1785) from northwestern Iran using a molecular approach. A total of 6,759 pond snails were collected from 28 freshwater bodies in West Azarbaijan. PCR was performed to amplify a 618-bp fragment of the nuclear 28 SrRNA gene of Fasciola. The PCR products were digested by AvaII restriction enzyme to create restriction fragment length polymorphism (RFLP) patterns specific for the detection of F. gigantica. Of the total collected snails 496 (7.34 %) were L. auricularia, among which 4.64% (23 out of 496) were infected with a Fasciola species according to the PCR analysis. Only 2.22% (11 out of 496) of the infected snails were from the mountainous areas. The highest Fasciola infection rate recorded in the snails of a single site was 1.81% (9 out of 496 snails). Based on the RFLP pattern, F. gigantica accounted for 2.42% of the infection rates in the study sites. Application of PCR-RFLP was proven to be a useful approach for valid and robust detection of the infection with F. gigantica in its intermediate host snails. These findings may therefore be applicable for establishment of the control programs against dissemination of the infection in different regions.

  7. Prevalence of Fasciola hepatica in the intermediate host Lymnaea truncatula detected by real time TaqMan PCR in populations from 70 Swiss farms with cattle husbandry.

    PubMed

    Schweizer, G; Meli, M L; Torgerson, P R; Lutz, H; Deplazes, P; Braun, U

    2007-11-30

    Bovine fasciolosis is an economically important parasitic disease. Quantitative real time PCR was utilized to determine the prevalence of Fasciola hepatica in the snail intermediate host Lymnaea truncatula from 70 selected, infected Swiss cattle farms, and to gain information on the infection risk to the definitive host. Snails from 130 habitats (36 streams, 21 wells, 24 drainage ditches, 33 spring swamps, 14 reeds, 1 drainage shaft and 1 pond) originating from 71 dairy cow pastures, 39 pastures for young stock, 14 hay fields and 6 dry cow pastures were collected. Of these, 51 populations were found to be infected with F. hepatica. A total of 4733 snails were examined of which 331 were infected (7.0%). The numbers of snails collected from different sites ranged from 1 to 159 snails. Clustering of infection in snails was found on the farm of origin with a mixed logistic model with random effects. The risk of infection of L. truncatula with F. hepatica was significantly higher in populations originating from spring swamps, wells and reeds compared to populations from streams. In addition the risk of snail infection was significantly lower in populations collected in young stock and dry cow pastures compared to dairy cow pastures. The greater the population size collected from a habitat also increased the risk of an individual snail being infected.

  8. Chlorophyllin Bait Formulation and Exposure to Different Spectrum of Visible Light on the Reproduction of Infected/Uninfected Snail Lymnaea acuminata

    PubMed Central

    Kumar, Navneet; Singh, D. K.; Singh, Vinay Kumar

    2016-01-01

    Fasciolosis is a waterborne disease, caused by Fasciola species. Snail Lymnaea acuminata is an intermediate host of these flukes. Control of snail population is major tool in reducing the incidences. Variation in light intensity and wavelength caused significant changes in reproduction pattern of snails. Maximum fecundity was noted with bait containing carbohydrate (starch, 468 ± 0.10/20 snails) or amino acid (serine, 319 ± 0.29/20 snails) as attractant. Sublethal feeding of chlorophyllin bait with starch or serine attractant to infected and uninfected snails caused significant reduction in fecundity, hatchability, and survivability. These significant changes are observed in snails exposed to different spectral band of visible light and sunlight. Maximum fecundity of 536 ± 2.0 and minimum of 89.3 ± 0.4 were noted in snails not fed with bait and exposed to sunlight and red spectral band, respectively. There was complete arrest in the fecundity of infected and uninfected snails and no survivability of uninfected snails after 48 h feeding with bait containing chlorophyllin + attractant. Minimum hatchability (9.25 ± 0.5) was noted in red light exposed, chlorophyllin + starch fed infected snails and hatching period of bait fed snails was prolonged. Conclusively, chlorophyllin bait and red light reduce reproduction capacity in snails. PMID:26925296

  9. A 5-HT1A-like receptor is involved in the regulation of the embryonic rotation of Lymnaea stagnalis L.

    PubMed

    Hiripi, László; Elekes, Károly

    2010-06-01

    Cilia driven rotation of the pond snail Lymnaea stagnalis embryos is regulated by serotonin (5-HT). In the present study, physiological and biochemical assays were used to identify the 5-HT receptor type involved in rotation. The 5-HTergic agonists applied stimulated the rotation by 180-400% and their rank order potency was as follows: LSD>5-HT>8-OH-DPAT>WB4101>5-CT. The applied antagonists, spiperone, propranalol and mianserin inhibited the 5-HT or 8-OH-DPAT stimulated rotation of the embryos by 50-70%. (3)H-5-HT was bound specifically to the washed pellet of the embryo homogenates. The specific binding of (3)H-5-HT was saturable and showed a single, high affinity binding site with K(d) 7.36 nM and B(max) 221 fmol/mg pellet values. This is the first report demonstrating the high affinity binding of (3)H-5-HT to the native receptor in molluscs. All of the pharmacons that stimulated the rotation or inhibited the 5-HT or 8-OH-DPAT evoked stimulation displaced effectively the binding of (3)H-5-HT. 5-HT resulted in the inhibition of forskolin stimulated cAMP accumulation, showing that 5-HT is negatively coupled to adenylate cyclase. Our results suggest that in the 5-HTergic regulation of the embryonic rotation in L. stagnalis a 5-HT(1A)-like receptor of the vertebrate type is involved. Copyright 2010 Elsevier Inc. All rights reserved.

  10. The effects of host size and temperature on the emergence of Echinoparyphium recurvatum cercariae from Lymnaea peregra under natural light conditions.

    PubMed

    Morley, N J; Adam, M E; Lewis, J W

    2010-09-01

    The production of cercariae from their snail host is a fundamental component of transmission success in trematodes. The emergence of Echinoparyphium recurvatum (Trematoda: Echinostomatidae) cercariae from Lymnaea peregra was studied under natural sunlight conditions, using naturally infected snails of different sizes (10-17 mm) within a temperature range of 10-29 degrees C. There was a single photoperiodic circadian cycle of emergence with one peak, which correlated with the maximum diffuse sunlight irradiation. At 21 degrees C the daily number of emerging cercariae increased with increasing host snail size, but variations in cercarial emergence did occur between both individual snails and different days. There was only limited evidence of cyclic emergence patterns over a 3-week period, probably due to extensive snail mortality, particularly those in the larger size classes. Very few cercariae emerged in all snail size classes at the lowest temperature studied (10 degrees C), but at increasingly higher temperatures elevated numbers of cercariae emerged, reaching an optimum between 17 and 25 degrees C. Above this range emergence was reduced. At all temperatures more cercariae emerged from larger snails. Analysis of emergence using the Q10 value, a measure of physiological processes over temperature ranges, showed that between 10 and 21 degrees C (approximately 15 degrees C) Q10 values exceeded 100 for all snail size classes, indicating a substantially greater emergence than would be expected for normal physiological rates. From 14 to 25 degrees C (approximately 20 degrees C) cercarial emergence in most snail size classes showed little change in Q10, although in the smallest size class emergence was still substantially greater than the typical Q10 increase expected over this temperature range. At the highest range of 21-29 degrees C (approximately 25 degrees C), Q10 was much reduced. The importance of these results for cercarial emergence under global climate change

  11. Accumulation and detoxication responses of the gastropod Lymnaea stagnalis to single and combined exposures to natural (cyanobacteria) and anthropogenic (the herbicide RoundUp(®) Flash) stressors.

    PubMed

    Lance, Emilie; Desprat, Julia; Holbech, Bente Frost; Gérard, Claudia; Bormans, Myriam; Lawton, Linda A; Edwards, Christine; Wiegand, Claudia

    2016-08-01

    Freshwater gastropods are increasingly exposed to multiple stressors in the field such as the herbicide glyphosate in Roundup formulations and cyanobacterial blooms either producing or not producing microcystins (MCs), potentially leading to interacting effects. Here, the responses of Lymnaea stagnalis to a 21-day exposure to non-MC or MC-producing (33μgL(-1)) Planktothrix agardhii alone or in combination with the commercial formulation RoundUp(®) Flash at a concentration of 1μgL(-1) glyphosate, followed by 14days of depuration, were studied via i) accumulation of free and bound MCs in tissues, and ii) activities of anti-oxidant (catalase CAT) and biotransformation (glutathione-S-transferase GST) enzymes. During the intoxication, the cyanobacterial exposure induced an early increase of CAT activity, independently of the MC content, probably related to the production of secondary cyanobacterial metabolites. The GST activity was induced by RoundUp(®) Flash alone or in combination with non MC-producing cyanobacteria, but was inhibited by MC-producing cyanobacteria with or without RoundUp(®) Flash. Moreover, MC accumulation in L. stagnalis was 3.2 times increased when snails were concomitantly exposed to MC-producing cyanobacteria with RoundUp(®), suggesting interacting effects of MCs on biotransformation processes. The potent inhibition of detoxication systems by MCs and RoundUp(®) Flash was reversible during the depuration, during which CAT and GST activities were significantly higher in snails previously exposed to MC-producing cyanobacteria with or without RoundUp(®) Flash than in other conditions, probably related to the oxidative stress caused by accumulated MCs remaining in tissues. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. In Vitro Effects of Mucus from the Mantle of Compatible (Lymnaea elodes) and Incompatible (Helisoma trivolvis) Snail Hosts on Fascioloides magna Miracidia.

    PubMed

    Coyne, Kathyrn; Laursen, Jeffrey R; Yoshino, Timothy P

    2015-06-01

    The epidermal mucus covering the surface of a snail represents an important barrier to trematode larvae attempting to penetrate the snail and may play a role in mediating snail-trematode compatibility. In this study, Facioloides magna miracidia were exposed to mucus harvested from a compatible snail host, Lymnaea elodes (palustris), and from an incompatible snail, Helisoma trivolvis . In vitro treatment of freshly hatched miracidia with snail-derived mucus exerted dramatically different effects on larvae depending on snail species. At the lowest dilution of mucus tested (1:3) mean damage rates (tegumental damage and/or larval lysis and death) were as high as 100% for miracidia exposed to H. trivolvis mucus, while none of F. magna miracidia were damaged in L. elodes mucus. A dilution series for each snail species, and treatments with heat and proteinase K were performed to characterize the component(s) of mucus inducing the observed morphological changes. The damaging effects of H. trivolvis mucus were concentration dependent and completely abrogated by heat (65 C, 30 min) and proteinase treatment, strongly implicating a heat-labile protein(s) in mucus as the active cytotoxic agent(s). In contrast to our prediction that miracidial contact with mucus of compatible L. elodes would trigger larval transformation, mucus from either snail species tested exhibited little to no activity. Overall these data demonstrate the presence of a potent cytotoxic protein-like factor in the mucus of F. magna -incompatible H. trivolvis , and its absence in the mucus of the compatible snail, L. elodes . This finding supports the notion that the epidermal mucus layer may be serving as an important determinant of larval trematode-snail compatibility.

  13. Seasonal variation in abiotic factors and ferulic acid toxicity in snail-attractant pellets against the intermediate host snail Lymnaea acuminata.

    PubMed

    Agrahari, P; Singh, D K

    2013-11-01

    Laboratory evaluation was made to access the seasonal variations in abiotic environmental factors temperature, pH, dissolved oxygen, carbon dioxide, electrical conductivity and ferulic acid toxicity in snail-attractant pellets (SAP) against the intermediate host snail Lymnaea acuminata in each month of the years 2010 and 2011. On the basis of a 24-h toxicity assay, it was noted that lethal concentration values of 4.03, 3.73% and 4.45% in SAP containing starch and 4.16, 4.23% and 4.29% in SAP containing proline during the months of May, June and September, respectively, were most effective in killing the snails, while SAP containing starch/proline + ferulic acid was least effective in the month of January/February (24-h lethal concentration value was 7.67%/7.63% in SAP). There was a significant positive correlation between lethal concentration value of ferulic acid containing SAP and levels of dissolved O2 /pH of water in corresponding months. On the contrary, a negative correlation was observed between lethal concentration value and dissolved CO2 /temperature of test water in the same months. To ascertain that such a relationship between toxicity and abiotic factors is not co-incidental, the nervous tissue of treated (40% and 80% of 24-h lethal concentration value) and control group of snails was assayed for the activity of acetylcholinesterase (AChE) in each of the 12 months of the same year. There was a maximum inhibition of 58.43% of AChE, in snails exposed to 80% of the 24-h lethal concentration value of ferulic acid + starch in the month of May. This work shows conclusively that the best time to control snail population with SAP containing ferulic acid is during the months of May, June and September.

  14. Impact of microcystin-producing cyanobacteria on reproductive success of Lymnaea stagnalis (Gastropoda, Pulmonata) and predicted consequences at the population level.

    PubMed

    Lance, Emilie; Alonzo, Frederic; Tanguy, Marion; Gérard, Claudia; Bormans, Myriam

    2011-06-01

    Our previous studies showed that microcystin (MC)-accumulation in the gastropod Lymnaea stagnalis and effects on life-history traits (survival, growth, and fecundity) varied according to age, exposure pathway (MC-producing cyanobacteria or dissolved MC), and presence or not of additional non-toxic food. This study investigated effects of exposure to MC-producing cyanobacteria or to dissolved MC of parent and of parent and egg masses of L. stagnalis on hatching success, duration of embryonic development and neonate survival. Secondly, the potential impact of MC-producing cyanobacterial proliferations (blooms) on L. stagnalis population growth, depending on bloom frequencies and recovery duration of life traits after exposure, was evaluated using a modelling approach. Experimental results showed that embryonic development was shortened in case of parent exposure to toxic cyanobacteria. Parent and eggs exposure to dissolved MC extended embryonic development and reduced hatching percentage, suggesting a permeability of egg masses to MC. Whatever exposure, neonate survival was reduced. Neonates exposed to cyanobacteria accumulated MCs 24 h after hatching, suggesting very early cyanobacteria ingestion. Modelling results showed that L. stagnalis population growth was influenced by the recovery time of life-history traits after exposure. When setting the latest at 6 weeks according to previous experiments, a frequency of one to four blooms per year strongly affected population dynamics and induced up to a 80-weeks delay compared to control in time required for populations to grow from 1 to 1000 individuals. Results are discussed in terms of impact of intoxication pathways on parents, eggs and neonates, and on population dynamics of L. stagnalis.

  15. Effects of the mixture of diquat and a nonylphenol polyethoxylate adjuvant on fecundity and progeny early performances of the pond snail Lymnaea stagnalis in laboratory bioassays and microcosms.

    PubMed

    Coutellec, Marie-Agnès; Delous, Georges; Cravedi, Jean-Pierre; Lagadic, Laurent

    2008-09-01

    Effects of the bipyridylium herbicide diquat and tank-mix adjuvant Agral90 were investigated on various life history traits of the freshwater pulmonate snail Lymnaea stagnalis. Trait expression was measured in simple laboratory bioassays on small size groups of snails, and under more complex, indoor microcosm conditions, on larger groups of snails. Microcosms were provided with sediment, plants, and fish, thus allowing a more complex level of intra and inter-specific interactions to develop. Treatments were performed with substances alone or in mixture, at concentrations ranging from 4.4 to 222.2microgl(-1) for diquat, and from 10 to 500microgl(-1) for Agral 90, under a fixed ratio design. Adult growth was negatively affected by diquat and its mixture with Agral 90 both at the highest concentrations (222.2 and 500microgl(-1), respectively). Fecundity expressed differently in bioassays and microcosms, but no effect of the chemicals could be observed on this trait. Progeny development was impaired by 222.2microgl(-1) diquat and its mixture with 500microgl(-1) Agral 90, as reflected by longer development time and reduced hatching rate of clutches laid by the exposed animals, as compared to the controls. Hatching data suggested that diquat bioavailability was lower in microcosms than under bioassay conditions. Consistently, chemical analysis showed that diquat disappeared more rapidly from the water in microcosms than in bioassays. Moreover, the differential expression of several life history traits under bioassays and microcosms conditions was probably also influenced by the level of intraspecific interaction, which differed among the systems. When significant, the effect of diquat was attenuated by the presence of Agral 90, indicating antagonistic interaction between the two substances. Such a deviation from additivity was partly validated statistically.

  16. Cross-phylum extrapolation of the Daphnia magna chronic biotic ligand model for zinc to the snail Lymnaea stagnalis and the rotifer Brachionus calyciflorus.

    PubMed

    De Schamphelaere, Karel A C; Janssen, Colin R

    2010-10-15

    We investigated if the chronic zinc biotic ligand model (BLM) developed earlier for the arthropod Daphnia magna could be extrapolated to predict chronic ecotoxicity of zinc as a function of water chemistry to two species from other phyla, i.e. the mollusc Lymnaea stagnalis and the rotifer Brachionus calyciflorus. We chronically exposed these two species to zinc in six natural surface waters. These water covered a wide range of pH (6.8-8.3), dissolved organic carbon (1.2-12.7mg/L) and Ca (8.8-118mg/L). Across all waters tested, the 28d-EC10s (200-1629μg Zn/L) and EC50s (382-2026μg Zn/L) for L. stagnalis spanned a 8.1-fold and 5.3-fold range, respectively. The 2d-EC10s (142-550μg Zn/L) and 2d-EC50s (195-1104μg Zn/L) for B. calyciflorus spanned a 3.9-fold and 5.7-fold range, respectively. The data indicated that higher pH and higher concentrations of Ca and DOC were generally associated with lower toxicity (higher ECx values). Furthermore, the chronic Zn BLM for D. magna, when calibrated only to reflect the intrinsic sensitivity of L. stagnalis and B. calyciflorus, was able to predict all ECx values with a less than 1.6-fold error, which demonstrates that the chronic D. magna Zn BLM can be extrapolated to other invertebrate phyla. This lends further support to the use of the chronic Zn BLM to account for bioavailability of zinc in aquatic risk assessment and the derivation of environmental quality standards.

  17. Effects of parasitism and pesticide exposure on characteristics and functions of hemocyte populations in the freshwater snail Lymnaea palustris (Gastropoda, Pulmonata).

    PubMed

    Russo, J; Lagadic, L

    2000-01-01

    Morphological characteristics and functions of hemocytes were used to compare the immunological effects of biological and chemical stress in the freshwater snail Lymnaea palustris. Animals were either infected by a trematode parasite (Metaleptocephalus sp.), or exposed to environmental contaminants, namely atrazine and hexachlorobenzene (HCB). Three populations of circulating hemocytes, morphologically and cytochemically distinct (round cells, hyalinocytes, granulocytes), were identified in both control and parasitized or pesticide-exposed snails. After 6 h of exposure, HCB and atrazine resulted in 8-fold increases in the mean total number of hemocytes, whereas only a 2.2-fold increase was observed 6 h after cercaria emission in parasitized snails. The impact of HCB was limited to the first 24 h of exposure, whereas long-lasting effects of atrazine were observed. Hyalinocytes and, to a lesser extent, round cells contributed most to the increases in hemocyte density in pesticide-exposed snails. Parasitism and atrazine treatment resulted in significant increases of lectin-stained hemocytes, whereas exposure to HCB did not affect the percentages of stained and unstained cells. Hemocyte phagocytic activity increased in HCB-exposed snails but with no concomitant change of the oxidative burst. Opposite results were obtained in atrazine-treated snail hemocytes, with unchanged phagocytosis and decreased phorbol 12-myristate 13-acetate-stimulated production of reactive oxygen intermediates. No increase in phagocytosis, or in the production of reactive oxygen intermediates, was observed in hemocytes from parasitized snails. Infection with the immunologically compatible trematode parasite Metaleptocephalus sp. and exposure to atrazine generated similar reactions from circulating hemocytes, whereas a different response pattern was observed in HCB-exposed snails.

  18. Impact of various salts on biology, physiology and tissue soluble proteins (SDS-PAGE) of Lymnaea natalensis and their infection with Fasciola gigantica miracidia.

    PubMed

    Mahmoud, Moamena Bayoumi

    2006-08-01

    The effect of sublethal concentrations of magnesium sulphate (MgSo4), sodium chloride (NaCl), potassium chloride (KCl), calcium sulphate (CaSo4) and sodium carbonate (Na2Co3) on survival, fecundity, Lymnaea natalensis infection with Fasciola gigantica miracidia and the activities of certain enzymes in tissue homogenate of these snails were evaluated. Tissue soluble proteins of the snails were analyzed by SDS-PAGE. The results indicated that Na2Co3 was more toxic to L. natalensis than the other salts. Egg laying capacity was declined after two weeks of continuous exposure to Na2Co3 (0.38 eggs/snail/week) compared to (13.85 eggs/snail/week) for controls. The lowest infection rate was among snails exposed to MgSo4 (31.25%) with a significant variation from controls (64.28%). The salts supperssed cercarial production of infected snails (14.6 metacercariae/ snail/stimulant) at MgSo4 compared to (59.3 metacercariae/ snail/stimulant) for controls. The maintenance of L. natalensis in the salts solutions for four successive weeks reduced the total protein content in their tissues (13.2 mg/g) at Na2Co3 (100 ppm) compared to (21.47 mg/g) for controls. The activity of alkaline phosphatase was significantly reduced in treated snails than controls. The electrophoretic data revealed a common band between controls and treated snails with a molecular weight of 79.42 to 80.55 kDa. There were bands in treated snails but not in controls (41.2 & 45 kDa). A band was detected for snails treated with each salt but not with controls or the other treated groups (28.68 kDa at NaCl, 100.75 kDa at CaSo4 & 205 Kda at KCl).

  19. Calicophoron daubneyi and Fasciola hepatica: characteristics of natural and experimental co-infections of these digeneans in the snail Lymnaea glabra.

    PubMed

    Vignoles, P; Titi, A; Mekroud, A; Rondelaud, D; Dreyfuss, G

    2017-01-01

    A retrospective study on different Lymnaea glabra samples collected from central France between 1993 and 2010 was carried out to determine the prevalence of natural co-infections with Calicophoron daubneyi and Fasciola hepatica, and to specify the composition of redial burdens. Experimental infections of L. glabra performed during the same period of time were also analysed to study metacercarial production of each digenean in co-infected snails. Controls were naturally or experimentally co-infected Galba truncatula. In natural co-infections, prevalence was 0.7% in L. glabra (186/25,128) and 0.4% in G. truncatula (137/31,345). Low redial burdens were found in these snails, with F. hepatica rediae significantly more numerous in L. glabra than in G. truncatula (7.5 per snail instead of 5.2). In contrast, the total numbers of C. daubneyi rediae in both lymnaeids were close to each other (4.3 and 3.0 rediae, respectively). In experimentally co-infected groups, prevalence was greater in G. truncatula than in the other lymnaeid (6.3% instead of 3.0%). Significantly shorter patent periods and lower metacercarial production for each digenean were noted in L. glabra than in G. truncatula. However, in both lymnaeids, the two types of cercariae were released during the same shedding waves and several peaks during the patent period were synchronous. In spite of a greater shell height for L. glabra, metacercarial production of both digeneans in co-infected snails was lower than that in G. truncatula, thus indicating a still incomplete adaptation between these French L. glabra and both parasites.

  20. Fasciola hepatica and Paramphistomum daubneyi: changes in prevalences of natural infections in cattle and in Lymnaea truncatula from central France over the past 12 years.

    PubMed

    Mage, Christian; Bourgne, Henri; Toullieu, Jean-Marc; Rondelaud, Daniel; Dreyfuss, Gilles

    2002-01-01

    A retrospective study was carried out over a 10- to 12-year period to analyse the changes in prevalences of natural fasciolosis and paramphistomosis among cattle and snails in central France, and to determine the causes which had induced these changes. The prevalences of natural fasciolosis in cattle increased from 1990 to 1993 (13.6% to 25.2%) and diminished afterwards up to 1999 (at 12.6%). Those of natural paramphistomosis showed a progressive increase between 1990 and 1999 (from 5.2 to 44.7%). The prevalences of natural infections and the numbers of free rediae counted in the snails (Lymnaea truncatula) infected with F. hepatica did not show any significant variations over time. By contrast, the prevalences of natural paramphistomosis in snails significantly increased from 1989 to 1996 and remained afterwards in the same range of values (3.7-5.3%), while the number of free rediae significantly increased up to 2000 (from a mean of 6.5 to 13.8 rediae per infected snail, respectively). Three hypotheses may explain the increase of paramphistomosis in cattle and snails: a better quality of diagnosis for the detection of P. daubneyi eggs in veterinary analysis laboratories, the use of specific molecules in the treatment of cattle fasciolosis since 1993, and the lack of an effective treatment up to now against cattle paramphistomosis. Since the objective of most farmers in central France is to obtain the highest antiparasitic efficiency with a single treatment of cattle per year, it is reasonable to assume that the prevalence of bovine paramphistomosis will continue to increase in the future.

  1. Distribution of Lymnaeidae (Mollusca: Pulmonata), intermediate snail hosts of Fasciola hepatica in Venezuela.

    PubMed

    Pointier, J P; Noya, O; Alarcón de Noya, B; Théron, A

    2009-08-01

    An extensive malacological survey was carried out between 2005-2009 in order to clarify the exact number of lymnaeid species which may be intermediate hosts of Fasciola hepatica in Venezuela. Four species were discovered during this survey, including two local species: Lymnaea cubensis and Lymnaea cousini and two exotic species: Lymnaea truncatula and Lymnaea columella. The most common local species was L. cubensis which was found at 16 out of the 298 sampling sites. This species has a large distribution area throughout the Northern part of Venezuela and was encountered from sea level to an altitude of 1,802 m in state of Trujillo. The second local species L. cousini was collected at only two sites of the Andean Region at altitudes of 3,550 m and 4,040 m, respectively. The European L. truncatula was found at 24 sites all located in the states of Mérida and Táchira at an altitude varying between 1,540-4,000 m. The respective distribution areas of L. cubensis and L. truncatula do not appear to overlap, but more detailed malacological surveys are needed. The fourth lymnaeid species, L. columella was collected in a canal from Mérida at an altitude of 1,929 m and in an irrigation canal from the state of Guárico, at an altitude of 63 m. The role of these four lymnaeid species in the transmission of fascioliasis in Venezuela is discussed.

  2. Tissue distribution and subcellular localization of trace metals in the pond snail Lymnaea stagnalis with special reference to the role of lysosomal granules in metal sequestration.

    PubMed

    Desouky, Mahmoud M A

    2006-05-01

    The present study was undertaken to elucidate the cellular mechanisms, which govern metal sequestration and detoxification in gastropods. For this purpose the pond snail, Lymnaea stagnalis was exposed to environmentally relevant concentrations of three species of metals (Al, Zn and Cd) for 30 days and the localization and fate of these metals were followed in different tissues of the snails. The measurement of relative distribution of metals between tissues revealed that the digestive gland and kidney account for most of the accumulated metals. Al and Cd (non-essential metals) were redistributed to the digestive gland, possibly because of the presence of specific binding entities in the digestive glands of the herein species. This study focuses on the role of intracellular metal-containing granules on metal sequestration. Three main types of granules were identified in the digestive gland cells namely small, green and yellow granules. The morphological examination and the progressive accumulation of elements within these granules revealed that they are developmental stages with the yellow granule being the mature one. The total number of these granules was found to be significantly increased upon exposure of the snails to Al only. This increase may be a response to the large amount of Al that is accumulated through feeding route of this grazing snail. X-ray microanalysis (XRMA) revealed that metals were localized in all three types of digestive gland granules. The increased amount of ligands (P and S) in the granules may give evidence for their role in metal sequestration. Levels of Al and P were positively correlated in the digestive gland granules. It is possible that aluminium is bound to phosphorus to render it insoluble and so to both immobilize it within the lysosome and to be excreted in a highly insoluble form. On the other hand, both Zn and Cd induced marked upregulation of S in mature (yellow) granules by 26- and 11-folds, respectively. The lysosomal

  3. Molecular characterisation of Galba truncatula, Lymnaea neotropica and L. schirazensis from Cajamarca, Peru and their potential role in transmission of human and animal fascioliasis

    PubMed Central

    2012-01-01

    Background Human and animal fascioliasis is emerging in many world regions, among which Andean countries constitute the largest regional hot spot and Peru the country presenting more human endemic areas. A survey was undertaken on the lymnaeid snails inhabiting the hyperendemic area of Cajamarca, where human prevalences are the highest known among the areas presenting a "valley transmission pattern", to establish which species are present, genetically characterise their populations by comparison with other human endemic areas, and discuss which ones have transmission capacity and their potential implications with human and animal infection. Methods Therefore, ribosomal DNA ITS-2 and ITS-1, and mitochondrial DNA 16S and cox1 were sequenced by the dideoxy chain-termination method. Results Results indicate the presence of three, morphologically similar, small lymnaeid species belonging to the Galba/Fossaria group: Galba truncatula, Lymnaea neotropica and L. schirazensis. Only one combined haplotype for each species was found. The ITS-1, 16S and cox1 haplotypes of G. truncatula are new. No new haplotypes were found in the other two species. This scenario changes previous knowledge, in which only L. viator (= L. viatrix) was mentioned. Galba truncatula appears to be the most abundant, with high population densities and evident anthropophyly including usual presence in human neighbourhood. Infection by Fasciola hepatica larval stages were molecularly confirmed in two populations of this species. The nearness between G. truncatula populations presenting liver fluke infection and both human settings and schools for children, together with the absence of populations of other lymnaeid species in the locality, suggest a direct relationship with human infection. Conclusions The geographical overlap of three lymnaeid species poses problems for epidemiological studies and control action. First, a problem in classifying lymnaeid specimens in both field and laboratory activities

  4. Molecular characterisation of Galba truncatula, Lymnaea neotropica and L. schirazensis from Cajamarca, Peru and their potential role in transmission of human and animal fascioliasis.

    PubMed

    Bargues, M Dolores; Artigas, Patricio; Khoubbane, Messaoud; Ortiz, Pedro; Naquira, Cesar; Mas-Coma, Santiago

    2012-08-15

    Human and animal fascioliasis is emerging in many world regions, among which Andean countries constitute the largest regional hot spot and Peru the country presenting more human endemic areas. A survey was undertaken on the lymnaeid snails inhabiting the hyperendemic area of Cajamarca, where human prevalences are the highest known among the areas presenting a "valley transmission pattern", to establish which species are present, genetically characterise their populations by comparison with other human endemic areas, and discuss which ones have transmission capacity and their potential implications with human and animal infection. Therefore, ribosomal DNA ITS-2 and ITS-1, and mitochondrial DNA 16S and cox1 were sequenced by the dideoxy chain-termination method. Results indicate the presence of three, morphologically similar, small lymnaeid species belonging to the Galba/Fossaria group: Galba truncatula, Lymnaea neotropica and L. schirazensis. Only one combined haplotype for each species was found. The ITS-1, 16S and cox1 haplotypes of G. truncatula are new. No new haplotypes were found in the other two species. This scenario changes previous knowledge, in which only L. viator (= L. viatrix) was mentioned. Galba truncatula appears to be the most abundant, with high population densities and evident anthropophyly including usual presence in human neighbourhood. Infection by Fasciola hepatica larval stages were molecularly confirmed in two populations of this species. The nearness between G. truncatula populations presenting liver fluke infection and both human settings and schools for children, together with the absence of populations of other lymnaeid species in the locality, suggest a direct relationship with human infection. The geographical overlap of three lymnaeid species poses problems for epidemiological studies and control action. First, a problem in classifying lymnaeid specimens in both field and laboratory activities, given their transmission capacity

  5. Primary structure of a low-molecular-mass N-linked oligosaccharide from hemocyanin of Lymnaea stagnalis. 3-O-methyl-D-mannose as a constituent of the xylose-containing core structure in an animal glycoprotein.

    PubMed

    Van Kuik, J A; Sijbesma, R P; Kamerling, J P; Vliegenthart, J F; Wood, E J

    1986-11-03

    Hemocyanin from the freshwater snail Lymnaea stagnalis is a high-molecular-mass copper-containing oxygen-transport protein, which occurs freely dissolved in the hemolymph. It is a glycoprotein containing fucose, xylose, 3-O-methylmannose, 3-O-methylgalactose, mannose, galactose, N-acetylgalactosamine and N-acetylglucosamine residues as sugar constituents. The N-glycosidic carbohydrate chains of this glycoprotein were released by hydrazinolysis of a pronase digest and subsequently fractionated as oligosaccharide-alditols on Bio-Gel P-4 followed by Lichrosorb-NH2. Investigation with 500-MHz 1H-NMR spectroscopy, in conjunction with sugar and methylation analysis revealed the lowest-molecular-mass glycan chain to have the structure: (Formula: see text).

  6. Impact of the redox-cycling herbicide diquat on transcript expression and antioxidant enzymatic activities of the freshwater snail Lymnaea stagnalis.

    PubMed

    Bouétard, Anthony; Besnard, Anne-Laure; Vassaux, Danièle; Lagadic, Laurent; Coutellec, Marie-Agnès

    2013-01-15

    The presence of pesticides in the environment results in potential unwanted effects on non-target species. Freshwater organisms inhabiting water bodies adjacent to agricultural areas, such as ditches, ponds and marshes, are good models to test such effects as various pesticides may reach these habitats through several ways, including aerial drift, run-off, and drainage. Diquat is a non-selective herbicide used for crop protection or for weed control in such water bodies. In this study, we investigated the effects of diquat on a widely spread aquatic invertebrate, the holarctic freshwater snail Lymnaea stagnalis. Due to the known redox-cycling properties of diquat, we studied transcript expression and enzymatic activities relative to oxidative and general stress in the haemolymph and gonado-digestive complex (GDC). As diquat is not persistent, snails were exposed for short times (5, 24, and 48 h) to ecologically relevant concentrations (22.2, 44.4, and 222.2 μg l(-1)) of diquat dibromide. RT-qPCR was used to quantify the transcription of genes encoding catalase (cat), a cytosolic superoxide dismutase (Cu/Zn-sod), a selenium-dependent glutathione peroxidase (gpx), a glutathione reductase (gred), the retinoid X receptor (rxr), two heat shock proteins (hsp40 and hsp70), cortactin (cor) and the two ribosomal genes r18S and r28s. Enzymatic activities of SOD, Gpx, Gred and glutathione S-transferase (GST) were investigated in the GDC using spectrophoto/fluorometric methods. Opposite trends were obtained in the haemolymph depending on the herbicide concentration. At the lowest concentration, effects were mainly observed after 24 h of exposure, with over-transcription of cor, hsp40, rxr, and sod, whereas higher concentrations down-regulated the expression of most of the studied transcripts, especially after 48 h of exposure. In the GDC, earlier responses were observed and the fold-change magnitude was generally much higher: transcription of all target genes increased

  7. Activity of Euphorbia splendens var. hislopii N.E.B. (Euphorbiaceae) latex against Lymnaea columella (Say, 1817) (Pulmonata: Lymnaeidae), intermediate host of Fasciola hepatica, Linnaeus, 1758 (Trematoda: Fasciolidae). 2: limited field-testing.

    PubMed

    de Vasconcellos, Mauricio Carvalho; de Amorim, Alziro

    2003-10-01

    The molluscicidal evaluation of Euphorbia splendens var. hislopii (Crown of thorns) against Lymnaea columella snails, intermediate host of Fasciola hepatica, in irrigation ditches of the Pisciculture Station at Universidade Federal Rural do Rio de Janeiro, was studied under limited field conditions. An aqueous solution of the latex at 5 mg/l was tested in two irrigation ditches (experimental and control ditches), after initial sampling of the snail population present. Twenty-four hours after application of the product, it was verified that 97.4% of free L. columella snails and 100% of snails of the same species captive in cages and used as sentinels at three points equidistant from the application site in the experimental ditch, died. For Biomphalaria tenagophila and Melanoides tuberculata snails, present in the experimental ditch, the mortality was 100%, for the species Pomacea spp. the mortality was 40%. No mortality was verified in the free mollusks, or in the sentinels in the ditch used as control. E. splendens var. hislopii latex is thus an efficient natural molluscicide, which may be used as an alternative control agent against L. columella.

  8. [Investigations on the pathogenesis of changes in somatic growth of Lymnaea stagnalis (Gastropoda: Pulmonata) experimentally infected with parthenites Opisthioglyphe ranae (Digenea: Plagiorchiida). I. Relative weight of accessory sex organs and synthetic activity of neurosecretory cells].

    PubMed

    Pokora, Z

    1996-01-01

    In the paper an attempt to define pathogenesis of changes in somatic growth of juvenile individuals of the popular freshwater snail Lymnaea stagnalis experimentally infected with parthenites of the trematode Opisthioglyphe ranae was undertaken. Significant enlargement of relative wet weight of examined accessory sex organs (albumen gland, oothecal gland, prostate, male copulatory organ) observed in infected snails permits to explain increase of their somatic growth basing on the hypothesis of disturbances in energetistic budget of the host-as a consequence of reduction by the parasite activity of the snail's reproductive system. Pathogenesis of this phenomenon has probably a complicated character, including also effect of parthenites on activity of the neurosecretory cells that control somatic growth in examined species of the snail. An argument for this standpoint is, observed in infected snails, increase of amount of neurosecretory material and RNA in cytoplasm of these cells (the light green cells of cerebral ganglia), as well as amount of the loose fraction of chromatine in their nuclei.

  9. Primary structure determination of seven novel N-linked carbohydrate chains derived from hemocyanin of Lymnaea stagnalis. 3-O-methyl-D-galactose and N-acetyl-D-galactosamine as constituents of xylose-containing N-linked oligosaccharides in an animal glycoprotein.

    PubMed

    Van Kuik, J A; Sijbesma, R P; Kamerling, J P; Vliegenthart, J F; Wood, E J

    1987-12-01

    Hemocyanin from the freshwater snail Lymnaea stagnalis is a high-molecular-mass copper-containing glyco-protein which functions as oxygen carrier in the hemolymph. To release the carbohydrate chains, the protein was digested by pronase followed by hydrazinolysis and reduction. The oligosaccharide-alditols were purified by gel permeation chromatography on Bio-Gel P-4, followed by HPLC on a Lichrosorb-NH2 column. Using 500-MHz 1H-NMR spectroscopy, in conjunction with sugar, methylation and deamination analysis, the following seven novel primary oligosaccharide structures could be unravelled. (Formula: see text).

  10. Acute toxicity, critical body residues, Michaelis-Menten analysis of bioaccumulation, and ionoregulatory disturbance in response to waterborne nickel in four invertebrates: Chironomus riparius, Lymnaea stagnalis, Lumbriculus variegatus and Daphnia pulex.

    PubMed

    Leonard, Erin M; Wood, Chris M

    2013-06-01

    We investigated the bioaccumulation and acute toxicity (48 h or 96 h) of Ni in four freshwater invertebrate species in two waters with hardness of 40 (soft water) and 140 mg L(-1) as CaCO(3) (hard water). Sensitivity order (most to least) was Lymnaea stagnalis > Daphnia pulex > Lumbriculus variegatus > Chironomus riparius. In all cases water hardness was protective against acute Ni toxicity with LC(50) values 3-3.5× higher in the hard water vs. soft water. In addition, higher water hardness significantly reduced Ni bioaccumulation in these organisms suggesting that competition by Ca and Mg for uptake at the biotic ligand may contribute to higher metal resistance. CBR50 values (Critical Body Residues) were less dependent on water chemistry (i.e. more consistent) than LC(50) values within and across species by ~2 fold. These data support one of the main advantages of the Tissue Residue Approach (TRA) where tissue concentrations are generally less variable than exposure concentrations with respect to toxicity. Whole body Ni bioaccumulation followed Michaelis-Menten kinetics in all organisms, with greater hardness tending to decrease B(max) with no consistent effect on K(d). Across species, acute Ni LC(50) values tended to increase with both K(d) and B(max) values - i.e. more sensitive species exhibited higher binding affinity and lower binding capacity for Ni, but there was no correlation with body size. With respect to biotic ligand modeling, log K(NiBL) values derived from Ni bioaccumulation correlated well with log K(NiBL) values derived from toxicity testing. Both whole body Na and Mg levels were disturbed, suggesting that disruption of ionoregulatory homeostasis is a mechanism of acute Ni toxicity. In L. stagnalis, Na depletion was a more sensitive endpoint than mortality, however, the opposite was true for the other organisms. This is the first study to show the relationship between Na and Ni.

  11. Molluscicidal action of the latex of Euphorbia splendens var. hislopii N.E.B. ("Christ's Crown") (Euphorbiaceae) against Lymnaea columella (Say, 1817) (Pulmonata: Lymnaeidae), intermediate host of Fasciola hepatica Linnaeus, 1758 (Trematode: Fasciolidae): 1- test in laboratory.

    PubMed

    de Vasconcellos, Mauricio Carvalho; de Amorim, Alziro

    2003-06-01

    The latex action of Euphorbia splendens var. hislopii (Christ's Crown) against snails Lymnaea columella, intermediate host of Fasciola hepatica, derived from irrigation ditches of the Station of Pisciculture at Universidade Federal Rural do Rio de Janeiro, was studied in the laboratory. Lab bioassays, using aqueous solutions of the latex, varying between 0.1 and 10 mg/l, have proven molluscicidal activity of the product collected on the same day the tests were performed, during the four seasons of the year, finding the following lethal concentrations (LC90): 1.51 mg/l in the spring; 0.55 mg/l in the summer; 0.74 mg/l in the fall and 0.93 mg/l in winter, after 24 h exposure of the snails, showing significant differences among the seasons of the year (ANOVA test, F = 11.01, G.L.= 3/33, p < 0.05), as well as among the concentrations (ANOVA test, F = 27.38, G.L.= 11/33, p < 0.05). In the summer, mortality reached 100% from concentration at 0.6 mg/l, the same during fall and in winter as of 1 mg/l, while in spring it only reached 100% mortality as of 2 mg/l. Mortality in the controls was low, reaching 5% in the summer and winter and 10% in the fall and spring. None of the samples died. During the assay, with an aqueous solution of the latex at a concentration of 5 mg/l, in order to check the time of duration of the product effect, in the laboratory, it was observed that the molluscicidal activity remained stable up to the 15th day after the beginning of the test with 100% mortality of L. columella, gradually losing its effect until the 23rd day, when we no longer observed animal mortality. In the control group, there was a random daily variation in mortality rate ranging 0-50% after 48 h of observation for 30 days.

  12. Larval stages of trematodes in gastropods from Lake Chicnahuapan, State of Mexico, Mexico.

    PubMed

    Barragán-Sáenz, Francisco Adrián; Sánchez-Nava, Petra; Hernández-Gallegos, Oswaldo; Salgado-Maldonado, Guillermo

    2009-10-01

    During the period from January to December (2007), 1,095 freshwater molluscs of four species were captured (Lymnaea stagnalis, Stagnicola elodes, Physella cubensis and Physa acuta) in Lake Chicnahuapan, State of Mexico, Mexico. Two hundred seventy-two (24.84% prevalence) of these molluscs were parasitised by 11 trematode species (from which two were not identified at the species level) having six cercariae species and five metacercariae species represented in five families. The cercariae Telorchis corti (Plagiorchiidae) and the metacercariae Cotylurus cornutus (Strigeidae) were the species with the highest prevalence among the examined snails. The highest percentage of infection was observed in L. stagnalis (27.45% of prevalence, n = 572) and P. cubensis (23.96%, n = 455). Twenty-one of the examined snails had multiple infections with up to three trematode species.

  13. Molluscicidal steroid glycoalkaloids possessing stereoisomeric spirosolane structures.

    PubMed

    Alzérreca, A; Hart, G

    1982-07-01

    Both the steroidal glycoalkaloid mixture obtained from Solanum mammosum fruits (solasonine 1 and solamargine 2) and the stereoisomeric glycosidic alkaloid tomatine 3 are toxic at 10 and 25 ppm to Lymnaea cubensis and Biomphalaria glabratus, respectively. Their aglycones solasodine 4 and tomatidine 5 obtained by hydrolysis of the glycosides showed no toxicity to either mollusk under the test conditions used. Preliminary structure-activity correlations indicate that the molluscicidal properties depend on the type of aglycones and on the glycoside bond. A common molecular structure in molluscicidal spirosolane and spirostane glycosides is recognized.

  14. Fascioliasis of livestock and snail host for Fasciola in the Altiplano Region of Bolivia.

    PubMed

    Ueno, H; Arandia, R; Morales, G; Medina, G

    1975-01-01

    Fascioliasis caused by Fasciola hepatica was a serious problem for sheep and alpacas in the Altiplano Region of Bolivia. In some provinces close to Lake Titicaca, the raising of sheep was forced to discontinue, because infection with the fluke made it unprofitable and almost impossible. It was proved that in the Altiplano Region, two species of freshwater snails, Lymnaea viatrix and L. cubensis var., served as intermediate hosts for F. hepatica. In some subtropical areas of Bolivia, these snails could not be found, although other Lymnaea sp. was widely distributed there. As it is possible for Lymnaea sp. to be intermediate host for the fluke, further studies are required on the identification. Acute fascioliasis of sheep occurred in the Altiplano Region principally during a period from May to July, or the dry season. In some areas, the mortality rate of infected sheep was roughly estimated as 15 to 25% annually. Contamination with Fasciola metacercariae of herbage and semi-aquatic plants grown in a swamp in one of these areas was biologically assessed, using guinea pigs. Plants of Compositae and Eleocharis sp. were contaminated most intensely and those of Senicio sp. and Vallisneria sp. carried a fairly large number of cysts, while plants of Scirpus sp. and Ranunclaceae carried only a few cysts. No signs of Fasciola infection were observed in any animal given the plants of Liliaceae.

  15. Epidemiology and population biology of pseudoperonospora cubensis: a model system for management of downy mildews

    USDA-ARS?s Scientific Manuscript database

    The resurgence of cucurbit downy mildew has dramatically influenced production of cucurbits and disease management systems at multiple scales. Long-distance dispersal is a fundamental aspect of epidemic development that influences the timing and extent of disease outbreaks. Dispersal potential of th...

  16. Spatial and Temporal Profiling of Griseofulvin Production in Xylaria cubensis Using Mass Spectrometry Mapping

    PubMed Central

    Sica, Vincent P.; Rees, Evan R.; Tchegnon, Edem; Bardsley, Robert H.; Raja, Huzefa A.; Oberlies, Nicholas H.

    2016-01-01

    A large portion of natural products research revolves around the discovery of new, bioactive chemical entities; however, studies to probe the biological purpose of such secondary metabolites for the host organism are often limited. Mass spectrometry mapping of secondary metabolite biosynthesis in situ can be used to probe a series of ecological questions about fungi that may be lost through traditional natural products chemistry extraction protocols. A griseofulvin-producing fungal culture of the Xylariaceae family, isolated as an endophyte of the tree Asimina triloba, was analyzed through a series of spatial and temporal mapping experiments. This fungus produced unique fungal characteristics, such as guttates and stroma, both of which were explored spatially. The distribution of griseofulvin on this culture in isolation was compared to its dispersal when grown in co-culture with a competing Penicillium species via a droplet–based surface sampling system. The fungistatic properties of griseofulvin were visualized, including the consequences for biosynthesis of polyhydroxyanthraquinones in a rival culture. PMID:27199902

  17. Spatial and Temporal Profiling of Griseofulvin Production in Xylaria cubensis Using Mass Spectrometry Mapping.

    PubMed

    Sica, Vincent P; Rees, Evan R; Tchegnon, Edem; Bardsley, Robert H; Raja, Huzefa A; Oberlies, Nicholas H

    2016-01-01

    A large portion of natural products research revolves around the discovery of new, bioactive chemical entities; however, studies to probe the biological purpose of such secondary metabolites for the host organism are often limited. Mass spectrometry mapping of secondary metabolite biosynthesis in situ can be used to probe a series of ecological questions about fungi that may be lost through traditional natural products chemistry extraction protocols. A griseofulvin-producing fungal culture of the Xylariaceae family, isolated as an endophyte of the tree Asimina triloba, was analyzed through a series of spatial and temporal mapping experiments. This fungus produced unique fungal characteristics, such as guttates and stroma, both of which were explored spatially. The distribution of griseofulvin on this culture in isolation was compared to its dispersal when grown in co-culture with a competing Penicillium species via a droplet-based surface sampling system. The fungistatic properties of griseofulvin were visualized, including the consequences for biosynthesis of polyhydroxyanthraquinones in a rival culture.

  18. Sympatric predator detection alters cutaneous respiration in Lymnaea.

    PubMed

    Orr, Mike; Lukowiak, Ken

    2010-01-01

    The ability of an organism to detect a predator and then to take the appropriate vigilance actions is paramount for survival of the species. Lab-reared snails (>250 generations) maintain their ability to detect predators and alter both aerial and cutaneous respiration. However, only the scent of a sympatric predator altered aerial respiration in freshly collected 'wild' snails. Here we test the hypothesis that the detection of a sympatric predator but not an allopatric predator will alter cutaneous respiration in freshly collected 'wild' snails. We find that Alberta snails while altering their cutaneous respiration to the scent of a sympatric predator (tiger salamander) do not alter respiration to the scent of a crayfish (an allopatric predator). In Dutch snails there is a greater alteration to the scent of crayfish (sympatric predator) than to an allopatric predator (tiger salamander).

  19. A new baseline for fascioliasis in Venezuela: lymnaeid vectors ascertained by DNA sequencing and analysis of their relationships with human and animal infection

    PubMed Central

    2011-01-01

    Background Human and animal fascioliasis poses serious public health problems in South America. In Venezuela, livestock infection represents an important veterinary problem whereas there appear to be few human cases reported, most of which are passively detected in health centres. However, results of recent surveys suggest that the situation may be underestimated in particular areas. To obtain a baseline for future fascioliasis assessment, studies were undertaken by means of rDNA ITS-2 and ITS-1 and mtDNA cox1 sequencing to clarify the specific status of Venezuelan lymnaeids, their geographical distribution and fascioliasis transmission capacity, by comparison with other American countries and other continents. Results Results obtained completely change the lymnaeid scenario known so far. The relatively rich lymnaeid fauna of Venezuela has been proven to include (i) Lymnaea meridensis and L. neotropica as the only native members, (ii) L. cubensis and Pseudosuccinea columella introduced from the Caribbean area, and (iii) Galba truncatula and L. schirazensis introduced from the Old World. The absence of representatives of the stagnicoline and Radix groups is remarkable. Four species are fascioliasis vectors: G. truncatula, L. cubensis and L. neotropica, which have the capacity to give rise to human endemic areas, and P. columella, which is a source of animal infection and is responsible for the spread of disease. Vector capacity in the apparently highland endemic L. meridensis is to be confimed, although may be expected given its phylogenetic relationships. Similarly as elsewhere, the non-transmitting L. schirazensis has been confused with L. cubensis, also with G. truncatula and possibly with L. neotropica. Conclusions The new scenario leads to the re-opening of many disease aspects. In Venezuela, altitude appears to be the main factor influencing fascioliasis distribution. Human infection shows an altitude pattern similar to other Andean countries, although a

  20. Using next-generation sequencing to develop molecular diagnostics for Pseudoperonospora cubensis, the cucurbit downy mildew pathogen

    USDA-ARS?s Scientific Manuscript database

    Advances in Next Generation Sequencing (NGS) allow for rapid development of genomics resources needed to generate molecular diagnostics assays for infectious agents. NGS approaches are particularly helpful for organisms that cannot be cultured, such as the downy mildew pathogens, a group of biotrop...

  1. SPATIAL DISTRIBUTION OF LYMNAEIDAE (MOLLUSCA, BASOMMATOPHORA), INTERMEDIATE HOST OF Fasciola hepatica LINNAEUS, 1758 (TREMATODA, DIGENEA) IN BRAZIL

    PubMed Central

    Medeiros, Camilla; Scholte, Ronaldo Guilherme Carvalho; D'ávila, Sthefane; Caldeira, Roberta Lima; Carvalho, Omar dos Santos

    2014-01-01

    Snails of the family Lymnaeidae act as intermediate hosts in the biological cycle of Fasciola hepatica, which is a biological agent of fasciolosis, a parasitic disease of medical importance for humans and animals. The present work aimed to update and map the spatial distribution of the intermediate host snails of F. hepatica in Brazil. Data on the distribution of lymnaeids species were compiled from the Collection of Medical Malacology (Fiocruz-CMM, CPqRR), Collection of Malacology (MZUSP), “SpeciesLink” (CRIA) network and through systematic surveys in the literature. Our maps of the distribution of lymnaeids show that Pseudosuccinea columella is the most common species and it is widespread in the South and Southeast with few records in the Midwest, North and Northeast regions. The distribution of the Galba viatrix, G. cubensis and G. truncatula showed a few records in the South and Southeast regions, they were not reported for the Midwest, North and Northeast. In addition, in the South region there are a few records for G. viatrix and one occurrence of Lymnaea rupestris. Our findings resulted in the first map of the spatial distribution of Lymnaeidae species in Brazil which might be useful to better understand the fasciolosis distribution and delineate priority areas for control interventions. PMID:24879003

  2. Spatial distribution of Lymnaeidae (Mollusca, Basommatophora), intermediate host of Fasciola hepatica Linnaeus, 1758 (Trematoda, Digenea) in Brazil.

    PubMed

    Medeiros, Camilla; Scholte, Ronaldo Guilherme Carvalho; D'ávila, Sthefane; Caldeira, Roberta Lima; Carvalho, Omar Dos Santos

    2014-01-01

    Snails of the family Lymnaeidae act as intermediate hosts in the biological cycle of Fasciola hepatica, which is a biological agent of fasciolosis, a parasitic disease of medical importance for humans and animals. The present work aimed to update and map the spatial distribution of the intermediate host snails of F. hepatica in Brazil. Data on the distribution of lymnaeids species were compiled from the Collection of Medical Malacology (Fiocruz-CMM, CPqRR), Collection of Malacology (MZUSP), "SpeciesLink" (CRIA) network and through systematic surveys in the literature. Our maps of the distribution of lymnaeids show that Pseudosuccinea columella is the most common species and it is widespread in the South and Southeast with few records in the Midwest, North and Northeast regions. The distribution of the Galba viatrix, G. cubensis and G. truncatula showed a few records in the South and Southeast regions, they were not reported for the Midwest, North and Northeast. In addition, in the South region there are a few records for G. viatrix and one occurrence of Lymnaea rupestris. Our findings resulted in the first map of the spatial distribution of Lymnaeidae species in Brazil which might be useful to better understand the fasciolosis distribution and delineate priority areas for control interventions.

  3. Molluscicidal activities of aqueous extract of the sea anemone Parasicyonis actinostoloides against vector snails Bulinus truncatus and Lymnaea natalensis.

    PubMed

    el-Sayed, Kamelia Abass

    2006-08-01

    The aqueous extract of the sea anemone Parasicyonis actinostoloides showed molluscicidal effect against vector snails of Schistosoma hacematobium and Fasciola gigantica after 24 hours of exposure. LC50) and LC90 values for P. actinostoloides were 40 & 78.6 ppm for B. runcatus and 46.6 & 86.5 ppm for L. natalensis respectively. The effect of continuously exposure of B. truncatits and L. naltlensis to sublethal aqueous extract concentrations (LC0, LC10 & LC25) on survival rate, egg production and on infectivity of miracidia to infection with S. haematobium and F. gigantica were studied. The data showed that no B. truncatus survived more than 42, 32 & 27 days after exposure with a mean life span of 18.5, 13.3 & 11.1 days respectively. The death rate of B. truncatus with LC0 was highly significant as compared to treatment with LC10 & LC25 (p < 0.01). L. natalensis were more susceptible to the effect of aqueous extract than B. truncatus. LC0, LC10 & LC25, extract killed all L. natalensis through 32, 27 & 22 days. The mean life span of those exposed to LC0 was 12.37 days, high significant when compared with treated LC10 & LC25 ones (p < 0.01). The cumulative mortality rates of B. truncatus and L. natalensis in controls during the experimental study (52 days) was 60% & 75%, respectively. Egg production of B. truncatius and L. natalensis was not affected by sublethal concentrations. Control snails layed significantly higher no. of eggs than treated ones. B. truncatus stopped egg laying 17 days after exposure to LC25. those treated with LC10 & LC0 ceased to deposit eggs after 22 & 27 days respectively. The percent reduction in egg laying capacity of B. truncatus treated with LC0, LC10 & LC25 compared to controls was 77.1%, 93.2% & 92.8% respectively (p < 0.01). Similar reduction in egg production of treated L. natalensis cornpared to controls occurred, the percent reduction in egg production of snails treated with LC0, LC10 & LC25 in relation to controls was 78.4%, 92.4% & 94.7% respectively. Sublethal concentrations of aqueous extract of P. actinostoloides affected hatchability of B. truncatus and L. natalensis eggs. The data showed that eggs of B. truncatus and L. natalensis can hatch in all tested concentrations but with different rates. The eggs' hatchability in snails exposed to LC0, LCIo & LC25 extract at 5 days old was 44%, 38% & 30% in B. truncatus respectively. In L. natalensis eggs, the corresponding rates were lower 28%, 24% & 18% respectively. The infection of B. truncatuts and L. natalensis with S. haematobium n and F. giganlica miracidia was greatly reduced by the sublethal concentrations of aqueous extract of P. actinostoloides. The reduction of infection rate increased with the increased of sublethal concentrations. In B. truncatus the reduction was 43.2%, 57.6% & 76.6% compared to controls and in L. natalensis was 56.3%, 70.2% & 77.4%, respectively.

  4. [Ultrastructural changes in the MP3 neuron of the mollusk Lymnaea stagnalis after cryopreservation of the isolated brain].

    PubMed

    Dmitrieva, E V; Moshkov, D A; Gakhova, E N

    2006-01-01

    Investigation of a possibility of long-term storage of frozen (-196 degrees C) viable neurons and nervous tissue is one of the central present day problems. In this study ultrastructural changes in neurons of frozen-thawed snail brain were examined as a function of time. We studied the influence of cryopreservation, cryoprotectant (Me2SO), cooling to 4-6 degrees C, and a prolonged incubation in physiological solution at 4-6 degrees C on dictyosomes of Golgi apparatus, endoplasmic reticulum (ER) cisternae and mitochondria. It has been found that responses of these intracellular structures of cryopreserved neurons to the above influences are similar: dissociation of Golgi dictyosomes, swelling of endoplasmic reticulum cisternae and mitochondrial cristae. Both freezing-thawing and cryoprotectant were seen to cause an increase in the number of lysosomes, liposomes, myelin-like structures, and to form large vacuoles. The structural changes in molluscan neurons caused by cryopreservation with Me2SO (2 M) were reversible.

  5. The participation of NMDA receptors, PKC, and MAPK in the formation of memory following operant conditioning in Lymnaea

    PubMed Central

    2010-01-01

    Background Memory is the ability to store, retain, and later retrieve information that has been learned. Intermediate term memory (ITM) that persists for up to 3 h requires new protein synthesis. Long term memory (LTM) that persists for at least 24 h requires: DNA transcription, RNA translation, and the trafficking of newly synthesized proteins. It has been shown in a number of different model systems that NMDA receptors, protein kinase C (PKC) and mitogen activated protein kinase (MAPK) are all involved in the memory formation process. Results Here we show that snails trained in control conditions are capable of forming, depending on the training procedure used, either ITM or LTM. However, blockage of NMDA receptors (MK 801), inhibition of PKC (GF109203X hydrochloride) and MAPK activity (UO126) prevent the formation of both ITM and LTM. Conclusions The injection of either U0126 or GF109203X, which inhibit MAPK and PKC activity respectively, 1 hour prior to training results in the inhibition of both ITM and LTM formation. We further found that NMDA receptor activity was necessary in order for both ITM and LTM formation. PMID:20807415

  6. Fasciola hepatica: the characteristics of experimental infections in Lymnaea truncatula subjected to miracidia differing in their mammalian origin.

    PubMed

    Vignoles, P; Ménard, A; Rondelaud, D; Chauvin, A; Dreyfuss, G

    2001-11-01

    Experimental infections of Lymaea truncatula, using two susceptible snail populations (Berneuil, or Migné, central France) and four isolates of Fasciola hepatica miracidia differing in their mammalian host of origin (cattle, nutrias, rabbits, or sheep), were performed under laboratory conditions to determine whether the host of origin had an effect on the daily production of cercariae. Snails were each subjected to bimiracidial exposures and were then reared under semi-natural conditions (a constant temperature of 20 degrees C and natural photoperiod). Significantly lower values were noted in the rabbit groups for survival rates at day 30 post-exposure, as well as for prevalences of infection, snail growth. duration of shedding period, and the total numbers of cercariae these snails shed. The total number of cercariae shed by both nutria groups was significantly higher than those recorded in the six other infected groups. In the cattle, rabbit, and sheep (Berneuil only) groups, the peaks in the daily distribution of cercariae occurred between day 2 and day 4 after the first shedding, and the number of cercaria-shedding snails decreased with increasing number of shedding waves. In contrast, in the three other groups, the peaks were only observed between days 20 and 45. Snails shedding their cercariae during nine or more waves were numerous in these last groups. No infradian-type rhythm in the daily distribution of cercarial numbers over the shedding period was noted for any snail group. The highest production of F. hepatica cercariae in both nutria groups would be a consequence of a higher success rate of miracidia when they infected an allopatric population of snails. The absence of an infradian-type rhythm in the distribution of daily cercarial numbers in the eight groups suggests that this rhythm, if it occurs, would only be influenced by temperature and thus be limited to periods with optimal conditions for cercarial shedding.

  7. Host specificity shapes population structure of pinworm parasites in Caribbean reptiles.

    PubMed

    Falk, Bryan G; Perkins, Susan L

    2013-09-01

    Host specificity is one of the potential factors affecting parasite diversification because gene flow may be facilitated or constrained by the number of host species that a parasite can exploit. We test this hypothesis using a costructure approach, comparing two sympatric pinworm parasites that differ in host specificity - Parapharyngodon cubensis and Spauligodon anolis - on the Puerto Rican Bank and St. Croix in the Caribbean. Spauligodon anolis specializes on Anolis lizards, whereas P. cubensis parasitizes Anolis lizards as well as many other species of lizards and snakes. We collected lizards from across the Puerto Rican Bank and St. Croix, sampled them for S. anolis and P. cubensis and generated nuclear and mitochondrial sequence data from the parasites. We used these data to show that P. cubensis is comprised of multiple cryptic species that exhibit limited population structure relative to S. anolis, which is consistent with our prediction based on their host specificity. We also provide evidence that the distribution of P. cubensis species is maintained by competitive exclusion, and in contrast to previous theoretical work, the parasites with the greatest number of host species also reach the highest prevalence rates. Overall, our results are consistent with the hypothesis that host specificity shapes parasite diversification, and suggest that even moderate differences in host specificity may contribute to substantial differences in diversification.

  8. QTL mapping of downy mildew resistance in PI 197088 and PI 330628 cucumbers

    USDA-ARS?s Scientific Manuscript database

    Downy mildew (DM, Pseudoperonospora cubensis) is a devastating fungal disease of cucumber worldwide. Several plant introduction lines have been identified with high resistance to the post-2004 new DM strain found in the U.S. However, the inheritance of DM resistance is still not well defined. Molecu...

  9. Developing clones of Eucalyptus cloeziana resistant to rust (Puccinia psidii)

    Treesearch

    Rafael F. Alfenas; Marcelo M. Coutinho; Camila S. Freitas; Rodrigo G. Freitas; Acelino C. Alfenas

    2012-01-01

    Besides its high resistance to Chrysoporthe cubensis canker, Eucalyptus cloeziana F. Muell. is a highly valuable tree species for wood production. It can be used for furniture, electric poles, fence posts, and charcoal. Nevertheless, it is highly susceptible to the rust caused by Puccinia psidii, which...

  10. PCR detection of Pseudoperonospora humuli in air samples from hop yards

    USDA-ARS?s Scientific Manuscript database

    Downy mildew of hop, caused by Pseudoperonospora humuli, is an important disease in most regions of hop production and is managed largely with regular fungicide applications. A PCR assay specific to P. humuli and the related organism P. cubensis was developed and used to monitor airborne inoculum i...

  11. QTLs for downy mildew resistance and their association with LRR-RLK resistance gene analogs in cucumber

    USDA-ARS?s Scientific Manuscript database

    Downy mildew (DM) caused by the obligate oomycete Pseudoperonospora cubensis is an important disease of cucumber and other cucurbit crops. For more than 50 years, DM was effectively controlled in cucumber through host resistance. The dm-1 gene became less effective in 2004 due to the appearance of a...

  12. Helminth parasites of the Mediterranean gecko, Hemidactylus turcicus (Sauria: Gekkonidae), from Texas, United States with a summary of helminths of this host.

    PubMed

    McAllister, Chris T; Bursey, Charles R

    2016-09-01

    One hundred-thirty six Mediterranean geckos, Hemidactylus turcicus, were collected between December 1986 and March 2016 in Hardin (n = 7), Harris (n = 57), and Tom Green (n = 72) counties, Texas, USA., and examined for helminth parasites. Fifty-two H. turcicus (38%) were infected with at least one helminth species. Found were a trematode, Mesocoelium meggitti, three cestodes, Mesocestoides sp. (tetrathyridia), Oochoristica ameivae and Oochoristica scelopori, and four nematodes, Cosmocercoides variabilis, Oswaldocruzia pipiens, Parapharyngodon cubensis, and larvae of Physaloptera sp. Oochoristica ameivae, O. scelopori, P. cubensis, Physaloptera sp., and Os. pipiens represent new host records for H. turcicus and M. meggitti is reported from Texas for the first time. A summary of the helminth parasites of both native and non-native H. turcicus is presented.

  13. The hyphomycete genus Piricauda, with the description of a new species.

    PubMed

    Mercado Sierra, Angel; Guarro, Josep; Heredia, Gabriela

    2005-06-01

    The genus Piricauda comprises eight species characterized by monotretic conidiogenous cells and micronematous arched conidiophores: P. cochinensis, P. cubensis, P. longispora, P. mexicana, P. paraguayensis, P. pseudarthriae, P. taiwanensis, and P. vulcanensis sp. nov. P. caribensis is transferred to Acrodictys. Species usually colonize dead petioles and rachides of palms in tropical and subtropical areas, but can also be found on branches and leaves of different trees. The species are illustrated and briefly described, and a key to them is provided.

  14. Identification and characterization of potential NBS-encoding resistance genes and induction kinetics of a putative candidate gene associated with downy mildew resistance in Cucumis

    PubMed Central

    2010-01-01

    Background Due to the variation and mutation of the races of Pseudoperonospora cubensis, downy mildew has in recent years become the most devastating leaf disease of cucumber worldwide. Novel resistance to downy mildew has been identified in the wild Cucumis species, C. hystrix Chakr. After the successful hybridization between C. hystrix and cultivated cucumber (C. sativus L.), an introgression line (IL5211S) was identified as highly resistant to downy mildew. Nucleotide-binding site and leucine-rich repeat (NBS-LRR) genes are the largest class of disease resistance genes cloned from plant with highly conserved domains, which can be used to facilitate the isolation of candidate genes associated with downy mildew resistance in IL5211S. Results Degenerate primers that were designed based on the conserved motifs in the NBS domain of resistance (R) proteins were used to isolate NBS-type sequences from IL5211S. A total of 28 sequences were identified and named as cucumber (C. sativus = CS) resistance gene analogs as CSRGAs. Polygenetic analyses separated these sequences into four different classes. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed that these CSRGAs expressed at different levels in leaves, roots, and stems. In addition, introgression from C. hystrix induced expression of the partial CSRGAs in cultivated cucumber, especially CSRGA23, increased four-fold when compared to the backcross parent CC3. Furthermore, the expression of CSRGA23 under P. cubensis infection and abiotic stresses was also analyzed at different time points. Results showed that the P. cubensis treatment and four tested abiotic stimuli, MeJA, SA, ABA, and H2O2, triggered a significant induction of CSRGA23 within 72 h of inoculation. The results indicate that CSRGA23 may play a critical role in protecting cucumber against P. cubensis through a signaling the pathway triggered by these molecules. Conclusions Four classes of NBS-type RGAs were successfully isolated

  15. One-trial reward learning in the snail Lymnea stagnalis.

    PubMed

    Alexander, J; Audesirk, T E; Audesirk, G J

    1984-01-01

    We present evidence that the pond snail Lymnaea stagnalis is capable of aquisition and extensive retention of an appetitively reinforced feeding response after only a single training trial. Food-deprived snails presented with a single pairing of a phagostimulant (a mixture of sucrose and casein digest) and a novel, non-food chemostimulus (amyl acetate) subsequently made feeding responses to the amyl acetate and retained the association for at least 19 days. This demonstration of one-trial, non-aversive classical conditioning enhances the utility of Lymnaea stagnalis as a model system for the detailed analysis of neural mechanisms underlying plasticity.

  16. Morphological and Molecular Characterization of Lymnaeid Snails and Their Potential Role in Transmission of Fasciola spp. in Vietnam

    PubMed Central

    Doanh, Pham Ngoc; The, Dang Tat; Loan, Ho Thi; Losson, Bertrand; Caron, Yannick

    2013-01-01

    Freshwater snails of the family Lymnaeidae play an important role in the transmission of fascioliasis worldwide. In Vietnam, 2 common lymnaeid species, Lymnaea swinhoei and Lymnaea viridis, can be recognized on the basis of morphology, and a third species, Lymnaea sp., is known to exist. Recent studies have raised controversy about their role in transmission of Fasciola spp. because of confusion in identification of the snail hosts. The aim of this study is, therefore, to clarify the identities of lymnaeid snails in Vietnam by a combination of morphological and molecular approaches. The molecular analyses using the second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA clearly showed that lymnaeids in Vietnam include 3 species, Austropeplea viridis (morphologically identified as L. viridis), Radix auricularia (morphologically identified as L. swinhoei) and Radix rubiginosa (morphologically identified as Lymnaea sp.). R. rubiginosa is a new record for Vietnam. Among them, only A. viridis was found to be infected with Fasciola spp. These results provide a new insight into lymnaeid snails in Vietnam. Identification of lymnaeid snails in Vietnam and their role in the liver fluke transmission should be further investigated. PMID:24516270

  17. Morphological and molecular characterization of lymnaeid snails and their potential role in transmission of Fasciola spp. in Vietnam.

    PubMed

    Dung, Bui Thi; Doanh, Pham Ngoc; The, Dang Tat; Loan, Ho Thi; Losson, Bertrand; Caron, Yannick

    2013-12-01

    Freshwater snails of the family Lymnaeidae play an important role in the transmission of fascioliasis worldwide. In Vietnam, 2 common lymnaeid species, Lymnaea swinhoei and Lymnaea viridis, can be recognized on the basis of morphology, and a third species, Lymnaea sp., is known to exist. Recent studies have raised controversy about their role in transmission of Fasciola spp. because of confusion in identification of the snail hosts. The aim of this study is, therefore, to clarify the identities of lymnaeid snails in Vietnam by a combination of morphological and molecular approaches. The molecular analyses using the second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA clearly showed that lymnaeids in Vietnam include 3 species, Austropeplea viridis (morphologically identified as L. viridis), Radix auricularia (morphologically identified as L. swinhoei) and Radix rubiginosa (morphologically identified as Lymnaea sp.). R. rubiginosa is a new record for Vietnam. Among them, only A. viridis was found to be infected with Fasciola spp. These results provide a new insight into lymnaeid snails in Vietnam. Identification of lymnaeid snails in Vietnam and their role in the liver fluke transmission should be further investigated.

  18. A novel monoclonal antibody-based immunoenzymatic assay for epidemiological surveillance of the vector snails of Fasciola hepatica (Trematoda: Digenea).

    PubMed

    Alba, Annia; Hernández, Hilda M; Marcet, Ricardo; Vázquez, Antonio A; Figueredo, Mabel; Sánchez, Jorge; Otero, Oscar; Sarracent, Jorge

    2015-02-01

    Fasciolosis is a globally distributed snail-borne disease which requires economic consideration due to its enormous impact on veterinary medicine. During recent decades, this parasitosis has also shown increasing prevalence in human populations worldwide. The dissemination and successful transmission of fasciolosis ultimately depends on the existence of susceptible snails that act as intermediate hosts. Therefore, to accomplish effective control of this disease, surveillance and detection of the infected intermediate host would be essential. The screening of trematodes within snails using classical parasitological examination of the larvae can be unreliable (sensitivity and specificity vary depending on the time of infection and the experience of the observer) and relatively costly when using molecular biological methods during large-scale monitoring. Here we propose a novel monoclonal antibody-based immunoenzymatic assay to detect ongoing Fasciola hepatica infection in lymnaeid snails. Anti-F. hepatica rediae mouse monoclonal antibodies were generated and used to develop a double monoclonal antibody-based ELISA for parasite detection. Fasciola hepatica-infected and uninfected laboratory-reared Galba cubensis and Pseudosuccinea columella were used for assessment of the developed ELISA. Experimentally infected snails were dissected and examined for parasite larvae as the "gold standard" method. Sensitivity results were 100% for both snail species, while specificity was 98% for G. cubensis and 100% for P. columella. No cross-reactivity was detected in lymnaeids infected with Trichobilharzia sp. or Cotylophoron sp. The ELISA enabled detection of the infection from day 8 p.i. in G. cubensis while in P. columella it was noted as early as day 4. To our knowledge no previous immunoassays have been reported to detect helminth-infected snails and the developed sandwich ELISA method is therefore suggested for infection status validation in natural populations of lymnaeid

  19. First description of deep-water elasmobranch assemblages in the Exuma Sound, The Bahamas

    NASA Astrophysics Data System (ADS)

    Brooks, Edward J.; Brooks, Annabelle M. L.; Williams, Sean; Jordan, Lance K. B.; Abercrombie, Debra; Chapman, Demian D.; Howey-Jordan, Lucy A.; Grubbs, R. Dean

    2015-05-01

    Deep-sea chondrichthyans, like many deep-water fishes, are very poorly understood at the most fundamental biological, ecological and taxonomic levels. Our study represents the first ecological investigation of deep-water elasmobranch assemblages in The Bahamas, and the first assessment of species-specific resilience to capture for all of the species captured. Standardised deep-water longline surveys (n=69) were conducted September to December 2010 and 2011 between 472 m and 1024 m deep, resulting in the capture of 144 sharks from 8 different species. These included the Cuban dogfish, Squalus cubensis, the bigeye sixgill shark, Hexanchus nakamurai, the bluntnose sixgill shark, Hexanchus griseus, the smooth dogfish, Mustelus canis insularis, the roughskin dogfish, Centroscymnus owstoni, Springer's sawtail catshark, Galeus springeri and the false catshark, Pseudotriakis microdon. Preliminary genetic analysis indicated two or more species of gulper sharks, Centrophorus spp.; however, for the present study they were treated as a single species complex. Water depth and distance from the rocky structure of the Exuma Sound wall were inversely correlated with species richness, whereas seabed temperature was directly correlated with species richness. These variables also had a significant influence on the abundance and distribution of many species. Expanded depth ranges were established for S. cubensis and H. nakamurai, which, in the case of S. cubensis, is thought to be driven by thermal preferences. At-vessel mortality rates increased significantly with depth, and post-release mortality was thought to be high for some species, in part due to high post-release predation. This study highlights the importance of utilising strategic geographic locations that provide easy access to deep water, in combination with traditional expedition-based deep-ocean science, to accelerate the acquisition of fundamental ecological and biological insights into deep-sea elasmobranchs.

  20. Phylogeography of Pinus subsection Australes in the Caribbean Basin

    PubMed Central

    Jardón-Barbolla, Lev; Delgado-Valerio, Patricia; Geada-López, Gretel; Vázquez-Lobo, Alejandra; Piñero, Daniel

    2011-01-01

    Background and Aims Four species of Pinus subsection Australes occur in the Caribbean Basin: P. caribaea, P. cubensis, P. maestrensis and P. occidentalis. This study analyses the phylogeography of these species to assess possible colonization events from Central America to the islands and subsequent population expansions during glacial periods driven by both drier climate and larger emerged land areas. Methods Allele size data were obtained for plastid microsatellites for 314 individuals from 24 populations, covering the distribution range of subsection Australes in the Caribbean Basin. Key Results In total, 113 plastid haplotypes were identified. The highest genetic diversity was found in populations of P. caribaea. Overall, Caribbean Basin populations fit the isolation by distance model. Significant phylogeographical structure was found (RST = 0·671 > permuted RST = 0·101; P < 0·0001). The haplotype network and a Bayesian analysis of population structure (BAPS) indicated different Central American origins for P. caribaea var. bahamensis and P. caribaea var. caribaea plastids, with Central America populations in northern and south-eastern groups. Sudden expansion times for BAPS clusters were close to three glacial maxima. Conclusions Central America contains ancestral plastid haplotypes. Population expansion has played a major role in the distribution of genetic diversity in P. caribaea var. hondurensis. Two colonization events gave rise to the P. caribaea var. bahamensis and P. caribaea var. caribaea lineages. Plastid variation in the eastern species (P. cubensis, P. maestrensis and P. occidentalis) evolved independently from that in P. caribaea var. caribaea. Incomplete lineage sorting between P. cubensis and P. maestrensis is apparent. Inferred expansion times for P. caribaea var. bahamensis and for the eastern lineages correspond to glacial maxima, whereas those for P. caribaea var. hondurensis correspond to the beginning of the temperature decrease that

  1. Morphological and molecular analyses of larval and adult stages of Echinoparyphium recurvatum von Linstow 1873 (Digenea: Echinostomatidae) from central Mexico.

    PubMed

    Sereno-Uribe, A L; Pinacho-Pinacho, C D; Sanchéz Cordero, V; García-Varela, M

    2015-07-01

    In central Mexico, populations of the freshwater snail Physella cubensis were infected with metacercariae from a species of Echinoparyphium (Digenea: Echinostomatidae). In the current study, we describe both larval and adult stages of this species obtained from experimental and natural infections. A total 180 snails were collected from Patzcuaro Lake, Michoacan state in central Mexico in July 2012. In the laboratory snails were placed in individual vials and exposed to light with the aim of observing emergence of cercariae. To obtain metacercariae, uninfected snails (P. cubensis) were exposed to cercariae. Chicks were infected with metacercariae to obtain adults. Nine days post-infection, eggs were recovered and incubated in tap water at room temperature to observe miracidia. Adults obtained from natural and experimentally infected hosts possess a head collar with 45 spines in two alternating rows, confirming the identification as Echinoparyphium recurvatum von Linstow 1873. To test the conspecificity of all stages, sequences of nuclear internal transcribed spacer 1 (ITS1), 5.8S and ITS2 rDNA were obtained from two adult worms recovered from chicks and also a natural avian host, the shoveler duck Anas clypeata, together with five cercarial and four metacercarial isolates from nine snails. The genetic divergence estimated among the 13 isolates was very low, ranging from 0 to 0.6%. Phylogenetic analyses inferred by maximum likelihood and Bayesian methods showed that all isolates of E. recurvatum form a single clade with strong support. The presence of E. recurvatum in P. cubensis and A. clypeata from central Mexico represents new host reports, and extends the distribution range in the Americas.

  2. Hallucinogenic mushrooms on the German market - simple instructions for examination and identification.

    PubMed

    Musshoff, F; Madea, B; Beike, J

    2000-09-11

    'Magic mushrooms' is the name most commonly given to psychoactive fungi containing the hallucinogenic components psilocybin and psilocin. Material confiscated by local authorities was examined using morphologic, microscopic, microchemical, and toxicological methods. Psilocybe cubensis was the most popular mushroom in the sample collective, followed by Psilocybe semilanceata, Panaeolus cyanescens and Psilocybe tampanensis. The alkaloid content was determined with <0.003-1.15% of psilocybin and 0.01-0.90% psilocin. Panaeolus cyanescens was the mushroom with highest levels of psilocybin and psilocin.

  3. [Ecology of river mollusks of medical and veterinary importance in 3 sites in La Habana province].

    PubMed

    Vázquez Perera, Antonio Alejandro; Gutiérrez Amador, Alfredo

    2007-01-01

    An ecological research study was carried out in freshwater mollusk populations of medical and veterinary importance, in order to determine the biotic and abiotic factors that affect their dynamics. It was observed that the principal abiotic factors influencing abundance of mollusks were total hardness, salinity, acidity, alkalinity and CO2 concentration. Both aquatic plants and specific relations among mollusk groups were the principal biotic factors that affected the molluskan fauna. Species like Fossaria cubensis and Tarebia granifera appeared affected when the site diversity increased whereas the tiarid Melanoides tuberculata prevailed in almost all the ecosystems.

  4. Aurapex penicillata gen. sp. nov. from native Miconia theaezans and Tibouchina spp. in Colombia.

    PubMed

    Gryzenhout, Marieka; Myburg, Henrietta; Rodas, Carlos A; Wingfield, Brenda D; Wingfield, Michael J

    2006-01-01

    Conidiomata of a fungus resembling Chrysoporthe cubensis, a serious canker pathogen of Eucalyptus spp. (Myrtaceae, Myrtales) in tropical and subtropical parts of the world, was found on Eucalyptus grandis in Colombia. Fruiting structures of the fungus could be distinguished from those of C. cubensis by their distinctly orange conidiomatal necks. This fungus also was found on several plant species native to Colombia including Tibouchina urvilleana, T. lepidota and Miconia theaezans (Melastomataceae, Myrtales). Morphological comparisons, as well as those based on sequences of the ITS1/ITS2 region of the ribosomal DNA repeat and the beta-tubulin gene, were used to characterize this fungus. Its pathogenicity was assessed on various plants from which it has been collected, either in field or greenhouse trials. Phylogenetic analyses showed that isolates reside in a clade distinct from the four clades accommodating Chrysoporthe, Cryphonectria, Endothia and Rostraureum. Members of this clade are distinguished by the presence of orange conidiomatal necks with black bases and a unique internal stromatal structure. No teleomorph has been found for this fungus, for which we have provided the name Aurapex penicillata gen. sp. nov. A. penicillata produced only small lesions after inoculation on young T. urvilleana, M. theaezans and E. grandis trees and appears not to be a serious pathogen.

  5. Morphological and chemical analysis of magic mushrooms in Japan.

    PubMed

    Tsujikawa, Kenji; Kanamori, Tatsuyuki; Iwata, Yuko; Ohmae, Yoshihito; Sugita, Ritsuko; Inoue, Hiroyuki; Kishi, Tohru

    2003-12-17

    Morphological and toxicological analyses were performed on hallucinogenic mushrooms that are currently circulated in Japan. Scanning electron microscope (SEM) indicated a three-dimensional microstructures in the mushrooms. The complementary use of SEM with an optical microscope was effective for observing characteristic tissues, such as basidiomycetes, spores, cystidia and basidia. Hallucinogenic alkaloids were extracted with methanol and determined by high performance liquid chromatography (HPLC) with a UV detector set at 220 nm. The psilocin/psilocybin contents in Psilocybe cubensis were in the range of 0.14-0.42%/0.37-1.30% in the whole mushroom (0.17-0.78%/0.44-1.35% in the cap and 0.09-0.30%/0.05-1.27% in the stem), respectively. The hallucinogenic alkaloids in Copelandia were 0.43-0.76%/0.08-0.22% in the whole mushroom (0.64-0.74%/0.02-0.22% in the cap and 0.31-0.78%/0.01-0.39% in the stem). It thus appears that P. cubensis is psilocybin-rich, whereas Copelandia is psilocin-rich.

  6. The spiny dogfish ('cação-bagre'): description of an envenoming in a fisherman, with taxonomic and toxinologic comments on the Squalus gender.

    PubMed

    Haddad, Vidal; Gadig, Otto Bismarck Fazzano

    2005-07-01

    The authors report an injury caused by a spiny dogfish (Squalus sp) in a professional fisherman that was got hurt in the left hand for a spine in the dorsal fin of the fish and felt excruciating local pain for 6 h and manifested local edema and erythema. The sharks of the Squalus gender, in a similar way to the gender Heterodontus, present two spines in position previous to the dorsal fins, with channels presenting a whitish mass, composed of great and vacuolated cells that produce venom. The Squalus gender has a complex taxonomy, with five nominal species mentioned in Brazil: S. acanthias, S. blainvillei, S. cubensis, S. megalops and S. mitsukurii. The species associated to the injury belongs to the group 'megalops/cubensis'. A detailed study on the taxonomy and toxinology of the Squalus gender in Brazil would be of vital importance in the resolution of those problems and it would serve as subsidy for any other works involving their representatives, besides with aspects of envenoming that this gender can cause and that has rare citations in the literature.

  7. Monogeneans on native and introduced freshwater fishes from Cuba with the description of a new species of Salsuginus Beverley-Burton, 1984 from Limia vittata (Poeciliidae).

    PubMed

    Mendoza-Franco, Edgar F; Vidal-Martínez, V M; Cruz-Quintana, Y; León, F L Prats

    2006-07-01

    During a parasitological survey carried out between March and September 2003 in Cuba, the following monogeneans were found on the gills of freshwater fishes: Salsuginus cubensis n. sp. on the Cuban molly Limia vittata Guichenot (Poeciliidae); Cichlidogyrus sclerosus Paperna & Thurston, 1969 and C. tilapiae Paperna, 1960 on the African cichlid Tilapia rendalli Boulenger (Cichlidae); Haplocleidus dispar Mueller, 1936 and Pterocleidus acer Mueller, 1936 (all Dactylogyridae) on the sunfish Lepomis macrochirus Rafinesque (Centrarchidae) (new geographical records); and Gyrodactylus sp. (Gyrodactylidae) on the biajaca Nandopsis tetracanthus Valenciennes (Cichlidae) (new host and geographical record). Salsuginus cubensis differs from all other species of the genus in the size and morphology of the copulatory complex. The occurrence of C. sclerosus, C. tilapiae, H. dispar and P. acer in their respective hosts is due to the introduction of these hosts to Cuba. A review of the species composition of the Monogenea in native and introduced freshwater fish from Cuba is presented and the zoogeographical distribution of the species found is briefly discussed.

  8. Gigantobilharzia, possible cause of cercarial dermatitis: Case report

    PubMed Central

    Omar, Hussein M.; Omer, Osama H.; Al-Dhubaibi, Mohammed S.

    2016-01-01

    Cercarial dermatitis (swimmer’s itch) is a worldwide, often neglected parasitic skin disease characterized by strong maculopapular skin eruption accompanied by intensive itching. A fisherman suffered from forearm dermatitis. Clinical history associated with the recovery of the avian schistosome; Gigantobilharzia from little green bee-eater (Merops orientalis najdanus) and collected Lymnaea snails supported the authors’ opinion that patient clinical signs are most likely due to the invasion of avian schistosome cercariae. PMID:27004065

  9. Spot light survey on fresh-water snails of medical importance in Al Fayoum Governorate, Egypt.

    PubMed

    Abo-Madyan, Ahmed A; Morsy, Tosson A; Motawea, Saad M; El Garhy, Manal F; Massoud, Ahmed M A

    2005-04-01

    In a survey carried out during Summer and Autumn of 2004, for snails of medical importance, nine species were recovered. These were Biomphalaria alexandrina, B. glabrata, B. pfeifferi, Bulinus truncatus, B. forskalii, Lymnaea natalensis, Bellamya (=Vivipara) unicolor, Physa acuta and Hydrobia musaensis. Parasitological examination revealed that B. alexandrina, B. glabrata and L. natalensis harboured immature stages of their concerned trematode parasites. Moreover, P. acuta harboured the immature stage of the nematode parasite Parastrongylus cantonensis.

  10. Spatiotemporal spread of cucurbit downy mildew in the eastern United States.

    PubMed

    Ojiambo, P S; Holmes, G J

    2011-04-01

    The dynamics of cucurbit downy mildew, caused by Pseudoperonospora cubensis, in the eastern United States in 2008 and 2009 were investigated based on disease records collected in 24 states as part of the Cucurbit downy mildew ipmPIPE monitoring program. The mean season-long rate of temporal disease progress across the 2 years was 1.4 new cases per day. Although cucurbit downy mildew was detected in mid-February and early March in southern Florida, the disease progressed slowly during the spring and early summer and did not enter its exponential phase until mid-June. The median nearest-neighbor distance of spread of new disease cases was ≈110 km in both years, with ≈15% of the distances being >240 km. Considering disease epidemics on all cucurbits, the epidemic expanded at a rate of 9.2 and 10.5 km per day in 2008 and 2009, respectively. These rates of spatial spread are at the lower range of those reported for the annual spread of tobacco blue mold in the southeastern United States, a disease that is also aerially dispersed over long distances. These results suggest that regional spread of cucurbit downy mildew may be limited by opportunities for establishment in the first half of the year, when fewer cucurbit hosts are available for infection. The O-ring statistic was used to determine the spatial pattern of cucurbit downy mildew outbreaks using complete spatial randomness as the null model for hypothesis testing. Disease outbreaks in both years were spatially aggregated and the extent of spatial dependence was up to 1,000 km. Results from the spatial analysis suggests that disease outbreaks in the Great Lakes and mid-Atlantic regions may be due to the spread of P. cubensis sporangia from outbreaks of the disease near the Georgia/South Carolina/North Carolina border rather than from overwintering sites in southern Florida. Space-time point pattern analysis indicated strong (P < 0.001) evidence for a space-time interaction and a space-time risk window of ≈3

  11. Coevolution between Hispaniolan crossbills and pine: does more time allow for greater phenotypic escalation at lower latitude?

    PubMed

    Parchman, Thomas L; Benkman, Craig W; Mezquida, Eduardo T

    2007-09-01

    Crossbills (Aves: Loxia) and several conifers have coevolved in predator-prey arms races over the last 10,000 years. However, the extent to which coevolutionary arms races have contributed to the adaptive radiation of crossbills or to any other adaptive radiation is largely unknown. Here we extend our previous studies of geographically structured coevolution by considering a crossbill-conifer interaction that has persisted for a much longer time period and involves a conifer with more variable annual seed production. We examined geographic variation in the cone and seed traits of two sister species of pines, Pinus occidentalis and P. cubensis, on the islands of Hispaniola and Cuba, respectively. We also compared the Hispaniolan crossbill (Loxia megaplaga) to its sister taxa the North American white-winged crossbill (Loxia leucoptera leucoptera). The Hispaniolan crossbill is endemic to Hispaniola whereas Cuba lacks crossbills. In addition and in contrast to previous studies, the variation in selection experienced by these pines due to crossbills is not confounded by the occurrence of selection by tree squirrels (Tamiasciurus and Sciurus). As predicted if P. occidentalis has evolved defenses in response to selection exerted by crossbills, cones of P. occidentalis have scales that are 53% thicker than those of P. cubensis. Cones of P. occidentalis, but not P. cubensis, also have well-developed spines, a known defense against vertebrate seed predators. Consistent with patterns of divergence seen in crossbills coevolving locally with other conifers, the Hispaniolan crossbill has evolved a bill that is 25% deeper than the white-winged crossbill. Together with phylogenetic analyses, our results suggest that predator-prey coevolution between Hispaniolan crossbills and P. occidentalis over approximately 600,000 years has caused substantial morphological evolution in both the crossbill and pine. This also indicates that cone crop fluctuations do not prevent crossbills and

  12. Blabericola rhyparobiae n. comb. (Apicomplexa: Eugregarinida: Blabericolidae), parasitizing the Madeira cockroach, Rhyparobia maderae (Dictyoptera: Blaberidae).

    PubMed

    Clopton, Richard E

    2014-02-01

    Blabericola rhyparobiae n. comb. (Apicomplexa: Eugregarinida: Blabericolidae) is redescribed from the Madeira cockroach, Rhyparobia maderae (Dictyoptera: Blaberidae: Oxyhaloinae: Nauphoetini). Oocysts within the genus are typically dolioform with nonprojecting polar plates. Those of B. rhyparobiae differ from all other species of Blabericola in being oblong rather than dolioform. Morphometrically, the oocysts of B. rhyparobiae are significantly narrower than those of any other known species in the genus; they are significantly longer than those of Blabericola haasi, Blabericola migrator, and Blabericola princisi, but they are significantly shorter than those of Blabericola cubensis (oocyst width 4.47 μm vs. 4.74 μm, 4.70 μm, 5.06 μm, 5.21 μm, respectively; oocyst length 8.98 μm vs. 7.94 μm, 7.93 μm, 8.85 μm, 9.26 μm, respectively). All 5 species are also distinguished by unique sporozoite-bearing cavity sizes and morphometric ratios. Gametocysts of Blabericola species are either orbicular (B. cubensis, B. princisi) or elliptoid (B. haasi , B. migrator, B. rhyparobiae). Among Blabericola species with elliptoid gametocysts, the gametocysts of B. rhyparobiae are intermediate in size relative to the much larger gametocysts of B. migrator and the much smaller gametocysts of B. haasi (gametocyst length 462.06 μm vs. 728.11 μm, 272.02 μm; gametocyst width 297.12 μm vs. 461.31 μm, 178.36 μm, respectively). No structurally unique feature of the gamont distinguishes among species of Blabericola, but gamonts of all 5 species differ morphometrically. Gamonts of B. rhyparobiae differ significantly from all other species in the genus in the primite's protomerite and deutomerite lengths, the satellite' deutomerite lengths, and the total length of both primite and satellite in association. The gamonts of B. rhyparobiae are significantly smaller than those of B. cubensis, B. migrator, and B. princisi but significantly larger than those of B. haasi and can be readily

  13. Effects of a non-native cichlid fish (African jewelfish, Hemichromis letourneuxi Sauvage 1880) on a simulated Everglades aquatic community

    USGS Publications Warehouse

    Schofield, Pamela J.; Slone, Daniel H.; Gregoire, Denise R.; Loftus, William F.

    2014-01-01

    In an 8-month mesocosm experiment, we examined how a simulated Everglades aquatic community of small native fishes, snails, and shrimp changed with the addition of either a native predator (dollar sunfish Lepomis marginatus) or a non-native predator (African jewelfish Hemichromis letourneuxi) compared to a no-predator control. Two snail species (Planorbella duryi, Physella cubensis) and the shrimp (Palaemonetes paludosus) displayed the strongest predator-treatment effects, with significantly lower biomasses in tanks with Hemichromis. One small native fish (Heterandria formosa) was significantly less abundant in Hemichromis tanks, but there were no significant treatment effects for Gambusia holbrooki, Jordanella floridae, or Pomacea paludosa (applesnail). Overall, there were few treatment differences between native predator and no-predator control tanks. The results suggest that the potential of Hemichromis to affect basal food-web species that link primary producers with higher-level consumers in the aquatic food web, with unknown consequences for Florida waters.

  14. Glycyrrhiza glabra extract protects plants against important phytopathogenic fungi.

    PubMed

    Schuster, C; Konstantinidou-Doltsinis, S; Schmitt, A

    2010-01-01

    In previous investigations an ethanolic plant extract from Glycyrrhiza glabra (2.5% w/v) showed 100% efficacy against late blight (Phytophthora infestans) on detached tomato leaves. Based on these findings, the objective of this work was to investigate the effect of this extract against different important plant pathogenic fungi. Tests were carried out on potted plants. Against P. infestans, efficacies of 75% and 58% were achieved on tomato and potato plants with 5% extract concentration, respectively. Against another Oomycete, Pseudoperonospora cubensis, on cucumber, application of a 2.5% extract led to an efficacy of above 90%. The EC50-value was calculated to be 0.5% In a trial on beans against bean rust (Uromyces appendiculatus), G. glabra extract (5% concentration) showed 92% efficacy. In contrast, against powdery mildew on cucumber (Podosphaera xanthii), no disease reduction was found. Overall, the results indicate a high potential for the extract of G. glabra to control a number of important plant pathogens.

  15. Pulley reef: a deep photosynthetic coral reef on the West Florida Shelf, USA

    USGS Publications Warehouse

    Culter, J.K.; Ritchie, K.B.; Earle, S.A.; Guggenheim, D.E.; Halley, R.B.; Ciembronowicz, K.T.; Hine, A.C.; Jarrett, B.D.; Locker, S.D.; Jaap, W.C.

    2006-01-01

    Pulley Reef (24°50′N, 83°40′W) lies on a submerged late Pleistocene shoreline feature that formed during a sea-level stillstand from 13.8 to 14.5 ka (Jarrett et al. 2005). The reef is currently 60–75 m deep, exhibits 10–60% coral cover, and extends over approximately 160 km2 of the sea floor. Zooxanthellate corals are primarily Agaricia lamarcki, A. fragilis, Leptoseris cucullata, and less common Madracis formosa, M. pharensis, M. decactis, Montastraea cavernosa, Porites divaricata, Scolymia cubensis and Oculina tenella. Coralline algae are comparable in abundance to stony corals. Other macroalgae include Halimeda tuna, Dictyota divaricata, Lobophora variegata, Ventricatri ventricosa, Verdigelas pelas, and Kallymenia sp. Anadyomene menziesii is abundant. The reef provides a habitat for organisms typically observed at much shallower depths, and is the deepest known photosynthetic coral reef on the North America continental shelf (Fig. 1).

  16. [Natural products from the tropical rain forest of Venezuela as inhibitors of HIV-1 replication].

    PubMed

    Walder, R; Kalvatchev, Z; Garzaro, D; Barrios, M

    1995-01-01

    More than 100 plant extracts from the Amazonian rain forest of Venezuela were evaluated for their cytotoxicity and inhibitory activity against the human immunodeficiency virus type-1 (HIV-1). Aqueous extracts from Fomitella supina (S # 0389-4), Phellinus rhabarbarinus (S # 0389-7), Trichaptum perrottetti (S # 0389-8) and Trametes cubensis (S # 0389-13), Polyporaceae exhibited strong anti-HIV-1 activity, without toxicity for Molt-4 lymphocytic cells. Our results demonstrated, that the compound(s) acted by mechanism of direct virion inactivation and by inhibition of syncytium formation in an in vitro culture system. These results support the suggestion that the test extracts specifically act at the level of CD4-gp120 binding. The active components of these extracts is at present unknown, but anti-AIDS agents, such as those found in this study, individually or in combination, may be of therapeutic relevance.

  17. Presence of Fasciola hepatica in feral nutria (Myocastor coypus) living in a public park in Brazil.

    PubMed

    El-Kouba, Maysa M A N; Marques, Sandra M T; Pilati, Célso; Hamann, Waldir

    2009-03-01

    Sixteen nutria (Myocastor coypus) from a protected area in Curitiba, Brazil, were sampled to determine the prevalence of Fasciola hepatica eggs and intestinal parasites and the presence of snails in the habitat used by nutria. The overall prevalence rates were 56.25% (9) for F. hepatica eggs, 87.50% (14) for cestode eggs, 56.25% (9) for ascarid eggs, 50% (8) for coccidian (Eimeriidae) oocysts, and 56.25% (9) for Strongyloidea eggs. Fasciola hepatica eggs had an average size of 138 microm x 72 microm. The following mollusks were found: Physa cubensis, Physa marmorata, and Biomphalaria tenagophyla. These results suggest that the infected nutria could serve as a source of contamination for other animals, humans, and surface water. This is the first report about parasites in nutria in the state of Paraná, Brazil.

  18. A revision of the genus Atelecrinus PH Carpenter (Echinodermata: Crinoidea).

    PubMed

    Messing, Charles G

    2013-01-01

    The unusual bathyal comatulid crinoid genus Atelecrinus is widespread in the Atlantic and tropical Pacific Oceans and currently includes three recognized species. A re-assessment based on examination of new and existing specimens requires establishment of two new genera and five new species, and returns three junior synonyms to species-level status. Paratelecrinus is erected to accommodate Atelecrinus wyvilli PH Carpenter, A. conifer AH Clark, A. cubensis PH Carpenter, P. orthotriremis, new species, P. amenouzume new species, P. laticonulus new species and P. telo new species. Adelatelecrinus is erected to accommodate Atelecrinus sulcatus AH Clark and Adelatelecrinus vallatus new species. Atelecrinus retains A. balanoides PH Carpenter and A. helgae AH Clark, which restricts the genus to the Atlantic. In both Paratelecrinus and Adelatelecrinus, the basals articulate with the centrodorsal via ligament bundles anchored in deep ringlike interradial pits that project into the centrodorsal cavity, whereas in Atelecrinus the centrodorsal rim has shallow interradial concavities and attaches to the basals via a tight junction with no obvious ligament bundles. The spoon-shaped aboral fossa in the basals of Paratelecrinus appears to be unique among articulate crinoids and differs from the smooth fossa found in both Atelecrinus and Adelatelecrinus. New material extends the range of the family to the Indian Ocean. A few species are now known from enough specimens to identify some ontogenetic and distributional variations. Proximal ray morphology varies substantially with size in P. cubensis and P. orthotriremis. A. balanoides generally occurs in deeper water in the Lesser Antilles than in the Bahamas and Strait of Florida, while P. orthotriremis occurs in shallower water in the Lesser Antilles and deeper in the Bahamas.

  19. Distribution and abundance of schistosomiasis and fascioliasis host snails along the Mara River in Kenya and Tanzania.

    PubMed

    Dida, Gabriel O; Gelder, Frank B; Anyona, Douglas N; Matano, Ally-Said; Abuom, Paul O; Adoka, Samson O; Ouma, Collins; Kanangire, Canisius K; Owuor, Phillip O; Ofulla, Ayub V O

    2014-01-01

    We purposively selected 39 sampling sites along the Mara River and its two perennial tributaries of Amala and Nyangores and sampled snails. In addition, water physicochemical parameters (temperature, turbidity, dissolved oxygen, conductivity, alkalinity, salinity and pH) were taken to establish their influence on the snail abundance and habitat preference. Out of the 39 sites sampled, 10 (25.6%) had snails. The snail species encountered included Biomphalaria pfeifferi Krauss - the intermediate host of Schistosoma mansoni Sambon, Bulinus africanus - the intermediate host of Schistosoma haematobium, and Lymnaea natalensis Krauss - the intermediate host of both Fasciola gigantica and F. hepatica Cobbold. Ceratophallus spp., a non-vector snail was also encountered. Most (61.0%) of the snails were encountered in streamside pools. Schistosomiasis-transmitting host snails, B. pfeifferi and B. africanus, were fewer than fascioliasis-transmitting Lymnaea species. All the four different snail species were found to be attached to different aquatic weeds, with B. pfeifferi accounting for over half (61.1%) of the snails attached to the sedge, followed by B. africanus and Lymnaea spp., accounting for 22.2 and 16.7%, respectively. Ceratophallus spp. were non-existent in sedge. The results from this preliminary study show that snails intermediate hosts of schistosomiasis and fascioliasis exists in different habitats, in few areas along the Mara River, though their densities are still low to have any noticeable impacts on disease transmission in case they are infected. The mere presence of the vector snails in these focal regions calls for their immediate control and institution of proper regulations, management, and education among the locals that can help curtail the spread of the snails and also schistosomiasis and fascioliasis within the Mara River basin.

  20. LASER BIOLOGY: Peculiarities of studying an isolated neuron by the method of laser interference microscopy

    NASA Astrophysics Data System (ADS)

    Yusipovich, Alexander I.; Novikov, Sergey M.; Kazakova, Tatiana A.; Erokhova, Liudmila A.; Brazhe, Nadezda A.; Lazarev, Grigory L.; Maksimov, Georgy V.

    2006-09-01

    Actual aspects of using a new method of laser interference microscopy (LIM) for studying nerve cells are discussed. The peculiarities of the LIM display of neurons are demonstrated by the example of isolated neurons of a pond snail Lymnaea stagnalis. A comparative analysis of the images of the cell and subcellular structures of a neuron obtained by the methods of interference microscopy, optical transmission microscopy, and confocal microscopy is performed. Various aspects of the application of LIM for studying the lateral dimensions and internal structure of the cytoplasm and organelles of a neuron in cytology and cell physiology are discussed.

  1. Peculiarities of studying an isolated neuron by the method of laser interference microscopy

    SciTech Connect

    Yusipovich, Alexander I; Kazakova, Tatiana A; Erokhova, Liudmila A; Brazhe, Nadezda A; Maksimov, Georgy V; Novikov, Sergey M; Lazarev, Grigory L

    2006-09-30

    Actual aspects of using a new method of laser interference microscopy (LIM) for studying nerve cells are discussed. The peculiarities of the LIM display of neurons are demonstrated by the example of isolated neurons of a pond snail Lymnaea stagnalis. A comparative analysis of the images of the cell and subcellular structures of a neuron obtained by the methods of interference microscopy, optical transmission microscopy, and confocal microscopy is performed. Various aspects of the application of LIM for studying the lateral dimensions and internal structure of the cytoplasm and organelles of a neuron in cytology and cell physiology are discussed. (laser biology)

  2. Effects of histochrom and emoxypin on biophysical properties of electroexitable cells.

    PubMed

    Mischenko, N P; Fedoreev, S A; Zapara, T A; Ratushnyak, A S

    2009-02-01

    Comparative investigation of effects of antioxidant agents histochrom and emoxypin on biophysical characteristics of isolated neurons from shell Lymnaea stagnalis under normal conditions and during oxidative stress was performed. Differently directed effects of these compounds on resting potential and transmembrane ion currents of neural cells under normal conditions were detected. Histochrom provides hyperpolarizing and emoxypin--depolarizing effect on neuronal membrane potential. Under conditions of oxidative stress both products possess antioxidant action. Obtained data allows coming closer to understanding of cellular-molecular mechanisms of protective action of compounds.

  3. [Radioecological studies of freshwater mollusks in the Chernobyl accident exclusion zone].

    PubMed

    Gudkov, D I; Nazarov, A B; Dziubenko, E V; Kaglian, A E; Klenus, V G

    2009-01-01

    Species-specificity and dynamics of 90Sr, 137Cs and some transuranic elements accumulation in bivalve and gastropod freshwater molluscs of the Chernobyl exclusion zone during 1997-2008 was analyzed. The results of radiation dose and chromosome aberration rate estimation and the analysis of hemolymph composition of freshwater snail (Lymnaea stagnalis L.) was produced. The absorbed dose rate was registered in the range of 0.3-85.0 microGy/h. In closed water bodies the heightened chromosome aberration rate (up to 27%) in embryo tissues, and also the change of haematological indexes for the adult individuals of snails was registered.

  4. Chronic lead exposure reduces junctional resistance at an electrical synapse.

    PubMed

    Audesirk, G; Audesirk, T

    1984-01-01

    Both acute and chronic lead exposure have been found to inhibit transmission at chemical synapses, possibly by interfering with inward calcium current. We have found that chronic lead exposure slightly reduces input resistance and greatly reduces the junctional resistance between two strongly electrically coupled neurons in the pond snail Lymnaea stagnalis. The net effect is to increase the strength of electrical coupling. A reduction in gap junctional resistance would also be expected to increase the flow of small molecules between cells. However, Lucifer Yellow injections did not reveal dye-coupling between the cells. Lead exposure also increases the capacitance of the neurons.

  5. Molluscicidal evaluation of three common plants from India.

    PubMed

    Singh, Ajay; Singh, Sunil Kumar

    2005-12-01

    Mortality caused by the aqueous extract of latex of Thevetia peruviana, Alstonia scholaris and Euphorbia pulcherrima against two harmful freshwater snails, Lymnaea acuminata and Indoplanorbis exustus, is reported. Latices of all the plants at high doses were also lethal to freshwater fish Channa punctatus, which shares the habitat with these snails, but within 24 h, LC90 of snail L. acuminata did not cause any mortality to fishes in a mixed population of snail and fish. Therefore, these plant extracts may eventually be of great value for the control of harmful aquatic snails and other molluscan pests.

  6. Lead uptake and lead loss in the fresh water field crab, Barytelphusa guerini, on exposure to organic and inorganic lead

    SciTech Connect

    Tulasi, S.J.; Yasmeen, R.; Reddy, C.P.; Rao, J.V.R.

    1987-07-01

    Lead is a heavy metal which is widely used in paint industry, pigments, dyes, electrical components and electronics, plastic chemicals and in various other things. Since some of the lead salts are soluble in water, lead presents a potential threat to aquatic organisms. Studies dealing with invertebrates include those on mortality, growth and lead uptake in Lymnaea palustris and bioaccumulation of heavy metals in oysters and mussels. Little information exists regarding the effect of lead on the fresh water crustaceans. Hence the present investigation has been undertaken to study the uptake and loss of lead on exposure to subtoxic levels or organic and inorganic lead.

  7. Synthesis, Spectroscopic and Toxicity Studies of Titanocene Chelates of Isatin-3-Thiosemicarbazones

    PubMed Central

    Vatsa, Garima; Pandey, O. P.; Sengupta, S. K.

    2005-01-01

    The reactions of bis(cyclopentadienyl)titanium(IV) dichloride with a new class of thiosemicarbazone (LH2), derived by condensing isatin with different N(4)-substituted thiosemicarbazides, have been studied and products of type [Cp2Ti(L)] have been isolated. On the basis of various physico-chemical and spectral studies, five coordinate structures have been assigned to these derivatives. Toxicity studies of titanocene complexes at tbur different concentrations have been carried out against snail Lymnaea acuminata. The effect of most potent compounds on the activity of acetylcholinesterase enzyme, which inhibits the activity of enzyme, possibly by the formation of enzyme-inhibitor complex, was also studied. PMID:18365096

  8. Mach-Zehnder interference microscopy optically records electrically stimulated cellular activity in unstained nerve cells.

    PubMed

    Kaul, R A; Mahlmann, D M; Loosen, P

    2010-10-01

    Dual-beam white light interference microscopy monitors changes in the optical density of the investigated object with high sensitivity. We report on the recording of dynamic changes in a neuron's optical density evoked by extracellular electrical stimulation. These recorded changes were analysed and unambiguously connected to the investigated object, an invertebrate neuron of the pond snail Lymnaea stagnalis. The results provide evidence for the method's applicability in visualizing cellular dynamics purely by evaluating changes in a cell's optical properties. © 2010 The Authors Journal compilation © 2010 The Royal Microscopical Society.

  9. Microelectrode investigation of neuroneal ageing from a single identified neurone.

    PubMed

    Patel, Bhavik Anil; Arundell, Martin; Parker, Kim H; Yeoman, Mark S; O'Hare, Danny

    2010-09-14

    Microelectrode amperometry is uniquely suited for characterising the dynamics of neurotransmitter release, as it offers unparalleled spatial and temporal resolution. We have used carbon fibre microelectrodes to study release of the monoamine neurotransmitter serotonin (5-HT) and the gaseous transmitter nitric oxide (NO) in intact central nervous system of the water snail, Lymnaea stagnalis. Analysis of spontaneous vesicular release of 5-HT and depolarisation-induced release of NO reveals significant differences with ageing that may be associated with changes in protein structure and function.

  10. Estimating Polygenic Models for Multivariate Data on Large Pedigrees

    PubMed Central

    Thompson, E. A.; Shaw, R. G.

    1992-01-01

    We have developed algorithms for the likelihood estimation of additive genetic models for quantitative traits on large pedigrees. The approach uses the expectation L-maximization (EM) algorithm, but avoids intensive computation. In this paper, we focus on extensions of previous work to the case of multivariate data. We exemplify the approach by analyses of bivariate data on a four-generation, 949-member pedigree of the snail Lymnaea elodes, and on a three-generation pedigree of the guppy Poecilia reticulata containing about 400 individuals. PMID:1516823

  11. Fasciola hepatica in snails collected from water-dropwort fields using PCR.

    PubMed

    Kim, Hwang-Yong; Choi, In-Wook; Kim, Yeon-Rok; Quan, Juan-Hua; Ismail, Hassan Ahmed Hassan Ahmed; Cha, Guang-Ho; Hong, Sung-Jong; Lee, Young-Ha

    2014-12-01

    Fasciola hepatica is a trematode that causes zoonosis mainly in cattle and sheep and occasionally in humans. Fascioliasis has been reported in Korea; however, determining F. hepatica infection in snails has not been done recently. Thus, using PCR, we evaluated the prevalence of F. hepatica infection in snails at 4 large water-dropwort fields. Among 349 examined snails, F. hepatica-specific internal transcribed space 1 (ITS-1) and/or ITS-2 markers were detected in 12 snails and confirmed using sequence analysis. Morphologically, 213 of 349 collected snails were dextral shelled, which is the same aperture as the lymnaeid snail, the vectorial host for F. hepatica. Among the 12 F. hepatica-infected snails, 6 were known first intermediate hosts in Korea (Lymnaea viridis and L. ollula) and the remaining 6 (Lymnaea sp.) were potentially a new first intermediate host in Korea. It has been shown that the overall prevalence of the snails contaminated with F. hepatica in water-dropwort fields was 3.4%; however, the prevalence varied among the fields. This is the first study to estimate the prevalence of F. hepatica infection using the vectorial capacity of the snails in Korea.

  12. Fasciola hepatica in Snails Collected from Water-Dropwort Fields using PCR

    PubMed Central

    Kim, Hwang-Yong; Choi, In-Wook; Kim, Yeon-Rok; Quan, Juan-Hua; Ismail, Hassan Ahmed Hassan Ahmed; Cha, Guang-Ho; Hong, Sung-Jong

    2014-01-01

    Fasciola hepatica is a trematode that causes zoonosis mainly in cattle and sheep and occasionally in humans. Fascioliasis has been reported in Korea; however, determining F. hepatica infection in snails has not been done recently. Thus, using PCR, we evaluated the prevalence of F. hepatica infection in snails at 4 large water-dropwort fields. Among 349 examined snails, F. hepatica-specific internal transcribed space 1 (ITS-1) and/or ITS-2 markers were detected in 12 snails and confirmed using sequence analysis. Morphologically, 213 of 349 collected snails were dextral shelled, which is the same aperture as the lymnaeid snail, the vectorial host for F. hepatica. Among the 12 F. hepatica-infected snails, 6 were known first intermediate hosts in Korea (Lymnaea viridis and L. ollula) and the remaining 6 (Lymnaea sp.) were potentially a new first intermediate host in Korea. It has been shown that the overall prevalence of the snails contaminated with F. hepatica in water-dropwort fields was 3.4%; however, the prevalence varied among the fields. This is the first study to estimate the prevalence of F. hepatica infection using the vectorial capacity of the snails in Korea. PMID:25548416

  13. Background concentrations of heavy metals in benthos from transboundary rivers of the Transbaikalia region, Russia.

    PubMed

    Kuklin, Aleksei Petrovich; Matafonov, Petr Viktorovich

    2014-02-01

    The concentrations (mg/kg dry weight) of Cu, Zn, As, Cd, Hg, and Pb were measured in benthic macroalgae and invertebrates collected in the upper transboundary tributaries of the Onon River, Transbaikalia, Russia. The background concentration ranges in Cladophora fracta, Ulothrix zonata and Zygnemataceae were: 6.4-9.1 for Cu, 27.2-73.1 for Zn, 0.4-0.9 for Cd, 6.7-35.3 for As, 0.01-0.02 for Hg, and 1.9-4.3 for Pb. In Brachycentrus americanus and Lymnaea media the concentration ranges were: 9.0-25.5 for Cu, 21.4-96.0 for Zn, 0.1-0.3 for Cd, 1.7-5.6 for As, 0.004-0.02 for Hg, and 0.4-2.2 for Pb. The concentrations of Cu, Zn, Pb, and Hg were consistent with data for uncontaminated areas. Under contamination conditions the concentrations in C. fracta were: 938 for Zn, 513 for Pb, and 9.5 for Cd; in Lymnaea media were: 46.8 for Cu, 176 for Zn, 52.3 for Pb, and 3.0 for Cd. All the organisms showed a common response to contamination, and consequently can be used as biomonitors of contamination by heavy metals.

  14. Parasites flicking the NPY gene on the host's switchboard: why NPY?

    PubMed

    De Jong-Brink, M; Reid, C N; Tensen, C P; Ter Maat, A

    1999-11-01

    It was investigated whether up-regulation of the NPY gene by the schistosome Trichobilharzia ocellata in its snail host Lymnaea stagnalis redirects the host's energy flows. We cloned the cDNA encoding Lymnaea NPY (LyNPY), purified and sequenced the peptide, and used synthesized peptide for physiological and morphological studies. Increasing the LyNPY titer in nonparasitized snails (mimicking parasitosis) by 1) implantation of slow-release pellets and 2) injections suppressed reproductive activity and reduced growth in a dose- and time-dependent manner without affecting food intake. When the LyNPY titer was back to normal, reproduction and growth were resumed, coinciding with a transient increase of food intake serving to replenish glycogen stores. Observations on double-immunostained whole mount preparations of brains support these data. A close association was found between LyNPY-positive axons and axons both from ovulation hormone-producing neurons and molluscan insulin-like peptide-producing neurons involved in regulation of growth. As no synaptic(-like) contacts were observed, it is supposed that LyNPY acts nonsynaptically. No morphological interaction was found between LyNPY-positive axons and motoneurons innervating the feeding apparatus. Our data explain why it is an advantageous strategy for endoparasites to up-regulate the highly conserved NPY gene in their host.

  15. Trophic factor-induced activity 'signature' regulates the functional expression of postsynaptic excitatory acetylcholine receptors required for synaptogenesis.

    PubMed

    Luk, Collin C; Lee, Arthur J; Wijdenes, Pierre; Zaidi, Wali; Leung, Andrew; Wong, Noelle Y; Andrews, Joseph; Syed, Naweed I

    2015-04-01

    Highly coordinated and coincidental patterns of activity-dependent mechanisms ("fire together wire together") are thought to serve as inductive signals during synaptogenesis, enabling neuronal pairing between specific sub-sets of excitatory partners. However, neither the nature of activity triggers, nor the "activity signature" of long-term neuronal firing in developing/regenerating neurons have yet been fully defined. Using a highly tractable model system comprising of identified cholinergic neurons from Lymnaea, we have discovered that intrinsic trophic factors present in the Lymnaea brain-conditioned medium (CM) act as a natural trigger for activity patterns in post- but not the presynaptic neuron. Using microelectrode array recordings, we demonstrate that trophic factors trigger stereotypical activity patterns that include changes in frequency, activity and variance. These parameters were reliable indicators of whether a neuron expressed functional excitatory or inhibitory nAChRs and synapse formation. Surprisingly, we found that the post- but not the presynaptic cell exhibits these changes in activity patterns, and that the functional expression of excitatory nAChRs required neuronal somata, de novo protein synthesis and voltage gated calcium channels. In summary, our data provides novel insights into trophic factor mediated actions on neuronal activity and its specific regulation of nAChR expression.

  16. Organic and inorganic lead inhibit neurite growth in vertebrate and invertebrate neurons in culture.

    PubMed

    Audesirk, G; Shugarts, D; Nelson, G; Przekwas, J

    1989-12-01

    Neurons from brains of chick embryos and pond snails (Lymnaea stagnalis) were cultured for 3 to 4 d in the presence of no toxins, inorganic lead (PbCl2), or organic lead (triethyl lead chloride). In chick neurons, inorganic lead reduced the percentage of cells that grew neurites (IC50 = 270 microM total lead, approximately 70 nM free Pb2+) but did not reduce the number of neurites per cell or the mean neurite length. Triethyl lead reduced the percentage of cells that grew neurites (IC50 = 0.24 microM) and the mean neurite length (extrapolated IC50 = 3.6 microM) but did not reduce the number of neurites per cell. In Lymnaea neurons, inorganic lead reduced the percentage of cells that grew neurites (IC50 = 13 microM total lead; approximately 10 nM free Pb2+). Triethyl lead reduced the percentage of cells that grew neurites (IC50 = 0.4 microM) and exerted significant toxicity at 0.2 microM. The two forms of lead affected neurite growth in qualitatively different ways, which suggests that their mechanisms of action are different.

  17. In vitro characterization of L-type calcium channels and their contribution to firing behavior in invertebrate respiratory neurons.

    PubMed

    Spafford, J David; Dunn, Tyler; Smit, August B; Syed, Naweed I; Zamponi, Gerald W

    2006-01-01

    L-type calcium channel activity has been associated with a number of cytoplasmic responses, including gene transcription and activation of calcium-dependent enzymes, yet their direct contribution to the electrical activities of neurons has remained largely unexplored. Here we report the cloning and functional characterization of a molluscan L-type calcium channel homologue, LCa(v)1, and investigate its role in coordinating neuronal firing patterns. The LCav1 channel exhibits many hallmarks of vertebrate L-type channels in that it is high-voltage activated, slowly inactivating, and dihydropyridine sensitive and displays calcium-dependent inactivation in recording solutions with standard EGTA concentrations. We show that despite comprising less than approximately 20% of the total whole cell current in identified Lymnaea respiratory network neurons, the L-type channels are essential for maintaining rhythmic action potential discharges without being involved in synaptic release. Our data therefore suggest an important role of L-type calcium channels in maintaining rhythmical pattern activity underlying breathing behavior in Lymnaea.

  18. Expression of a retinoic acid receptor (RAR)-like protein in the embryonic and adult nervous system of a protostome species.

    PubMed

    Carter, Christopher J; Rand, Christopher; Mohammad, Imtiaz; Lepp, Amanda; Vesprini, Nicholas; Wiebe, Olivia; Carlone, Robert; Spencer, Gaynor E

    2015-01-01

    The vitamin A metabolite, retinoic acid, is an important molecule in nervous system development and regeneration in vertebrates. Retinoic acid signaling in vertebrates is mediated by two classes of nuclear receptors, the retinoid X receptors (RXRs) and the retinoic acid receptors (RARs). Recently, evidence has emerged to suggest that many effects of retinoic acid are conserved between vertebrate and invertebrate nervous systems, even though the RARs were previously thought to be a vertebrate innovation and to not exist in non-chordates. We have cloned a full-length putative RAR from the CNS of the mollusc Lymnaea stagnalis (LymRAR). Immunoreactivity for the RAR protein was found in axons of adult neurons in the central nervous system and in growth cones of regenerating neurons in vitro. A vertebrate RAR antagonist blocked growth cone turning induced by exogenous all-trans retinoic acid, possibly suggesting a role for this receptor in axon guidance. We also provide immunostaining evidence for the presence of RAR protein in the developing, embryonic CNS, where it is also found in axonal processes. Using qPCR, we determined that LymRAR mRNA is detectable in the early veliger stage embryo and that mRNA levels increase significantly during embryonic development. Putative disruption of retinoid signaling in Lymnaea embryos using vertebrate RAR antagonists resulted in abnormal eye and shell development and in some instances completely halted development, resembling the effects of all-trans retinoic acid. This study provides evidence for RAR functioning in a protostome species.

  19. Bioanalytical Applications of Real-Time ATP Imaging Via Bioluminescence

    SciTech Connect

    Gruenhagen, Jason Alan

    2003-01-01

    The research discussed within involves the development of novel applications of real-time imaging of adenosine 5'-triphosphate (ATP). ATP was detected via bioluminescence and the firefly luciferase-catalyzed reaction of ATP and luciferin. The use of a microscope and an imaging detector allowed for spatially resolved quantitation of ATP release. Employing this method, applications in both biological and chemical systems were developed. First, the mechanism by which the compound 48/80 induces release of ATP from human umbilical vein endothelial cells (HUVECs) was investigated. Numerous enzyme activators and inhibitors were utilized to probe the second messenger systems involved in release. Compound 48/80 activated a G{sub q}-type protein to initiate ATP release from HUVECs. Ca2+ imaging along with ATP imaging revealed that activation of phospholipase C and induction of intracellular Ca2+ signaling were necessary for release of ATP. Furthermore, activation of protein kinase C inhibited the activity of phospholipase C and thus decreased the magnitude of ATP release. This novel release mechanism was compared to the existing theories of extracellular release of ATP. Bioluminescence imaging was also employed to examine the role of ATP in the field of neuroscience. The central nervous system (CNS) was dissected from the freshwater snail Lymnaea stagnalis. Electrophysiological experiments demonstrated that the neurons of the Lymnaea were not damaged by any of the components of the imaging solution. ATP was continuously released by the ganglia of the CNS for over eight hours and varied from ganglion to ganglion and within individual ganglia. Addition of the neurotransmitters K+ and serotonin increased release of ATP in certain regions of the Lymnaea CNS. Finally, the ATP imaging technique was investigated for the study of drug release systems. MCM-41-type mesoporous nanospheres were loaded with ATP and end-capped with mercaptoethanol

  20. Transmission patterns of Fasciola hepatica to ruminants in Sweden.

    PubMed

    Novobilský, Adam; Engström, Annie; Sollenberg, Sofia; Gustafsson, Katarina; Morrison, David A; Höglund, Johan

    2014-07-14

    Transmission patterns of Fasciola hepatica were investigated on beef cattle (n=3) and sheep (n=3) farms in Sweden between 2011 and 2012. The dynamics of fluke infection, particularly estimated time of infection, were screened each grazing season by ELISA detection of antibodies in lambs (n=94) and first grazing season calves (n=61). Colostral transfer of F. hepatica antibodies from seropositive ewes was detected in sheep up to 11 weeks of age. In sheep, the estimated time of infection differed significantly between herds and years. Typical 'winter infection' was observed on two sheep farms in 2012, but the most prevalent transmission pattern was found to be 'summer infection', characterised by infection of animals in late summer by F. hepatica originating from overwintered and/or spring-excreted eggs. In contrast, beef calves were infected mainly in September-October ('summer infection'). Furthermore, lymnaeid and succineid snails were collected on the pastures used by these animals both in spring and in the autumn each year. In total, 1726, 588, 138, 130, 93 and 42 specimens of Galba truncatula, Lymnaea palustris, Lymnaea glabra, Lymnaea fuscus, Radix peregra and Succinea putris, respectively, were collected and identified. These were subsequently examined for the presence of F. hepatica DNA by species-specific PCR and the findings compared against mean monthly rainfall and temperature data for each farm. The main intermediate host of the liver fluke was G. truncatula, with a prevalence range of F. hepatica infection from 0% to 82%. Only 1 out of 42 terrestrial S. putris tested positive for F. hepatica, casting doubt on the role of this species in transmission of F. hepatica in Sweden. In conclusion, two main peak periods of infection were observed: May-June (from overwintered infected snails='winter infection') and August-September (from metacercariae developed and produced by snails during summer='summer infection'). The occurrence and frequency of 'winter

  1. Genome size determination in peronosporales (Oomycota) by Feulgen image analysis.

    PubMed

    Voglmayr, H; Greilhuber, J

    1998-12-01

    Genome size was determined, by nuclear Feulgen staining and image analysis, in 46 accessions of 31 species of Peronosporales (Oomycota), including important plant pathogens such as Bremia lactucae, Plasmopara viticola, Pseudoperonospora cubensis, and Pseudoperonospora humuli. The 1C DNA contents ranged from 0.046 (45. 6 Mb) to 0.163 pg (159.9 Mb). This is 0.041- to 0.144-fold that of Glycine max (soybean, 1C = 1.134 pg), which was used as an internal standard for genome size determination. The linearity of Feulgen absorbance photometry method over this range was demonstrated by calibration of Aspergillus species (1C = 31-38 Mb) against Glycine, which revealed differences of less than 6% compared to the published CHEF data. The low coefficients of variation (usually between 5 and 10%), repeatability of the results, and compatibility with CHEF data prove the resolution power of Feulgen image analysis. The applicability and limitations of Feulgen photometry are discussed in relation to other methods of genome size determination (CHEF gel electrophoresis, reassociation kinetics, genomic reconstruction) that have been previously applied to Oomycota. Copyright 1998 Academic Press.

  2. Intron Derived Size Polymorphism in the Mitochondrial Genomes of Closely Related Chrysoporthe Species

    PubMed Central

    Kanzi, Aquillah Mumo; Wingfield, Brenda Diana; Steenkamp, Emma Theodora; Naidoo, Sanushka; van der Merwe, Nicolaas Albertus

    2016-01-01

    In this study, the complete mitochondrial (mt) genomes of Chrysoporthe austroafricana (190,834 bp), C. cubensis (89,084 bp) and C. deuterocubensis (124,412 bp) were determined. Additionally, the mitochondrial genome of another member of the Cryphonectriaceae, namely Cryphonectria parasitica (158,902 bp), was retrieved and annotated for comparative purposes. These genomes showed high levels of synteny, especially in regions including genes involved in oxidative phosphorylation and electron transfer, unique open reading frames (uORFs), ribosomal RNAs (rRNAs) and transfer RNAs (tRNAs), as well as intron positions. Comparative analyses revealed signatures of duplication events, intron number and length variation, and varying intronic ORFs which highlighted the genetic diversity of mt genomes among the Cryphonectriaceae. These mt genomes showed remarkable size polymorphism. The size polymorphism in the mt genomes of these closely related Chrysoporthe species was attributed to the varying number and length of introns, coding sequences and to a lesser extent, intergenic sequences. Compared to publicly available fungal mt genomes, the C. austroafricana mt genome is the second largest in the Ascomycetes thus far. PMID:27272523

  3. Effects of Washing Produce Contaminated with the Snail and Slug Hosts of Angiostrongylus cantonensis with Three Common Household Solutions

    PubMed Central

    Yeung, Norine W; Hayes, Kenneth A

    2013-01-01

    The emerging infectious disease angiostrongyliasis (rat lungworm disease) is caused by ingesting snails and slugs infected by the nematode Angiostrongylus cantonensis. The definitive hosts of A. cantonensis are rats and the obligatory intermediate hosts are slugs and snails. Many cases result from accidentally ingesting infected snails or slugs on produce (eg, lettuce). This study assessed three readily available household products as washing solutions for removing snails and slugs from produce (romaine lettuce) to lower the probability of accidentally ingesting them. The solutions were acetic acid (vinegar), sodium hypochlorite (bleach), and sodium chloride (domestic salt). Snail and slug species known to be intermediate hosts and that are common in the Hawaiian Islands were used in the experiments: the alien snail Succinea tenella, the alien semi-slug Parmarion martensi, and the alien slugs Veronicella cubensis and Deroceras laeve. None of the products was any more effective than washing and rinsing with tap water alone. Most snails and slugs were removed after treatment but some remained on the lettuce even after washing and rinsing the produce. Only washing, rinsing, and then rinsing each leaf individually resulted in complete removal of all snails and slugs. The study did not address removal of any remaining slime left by the snails and slugs, nor did it address killing of worms. PMID:23901391

  4. Effects of washing produce contaminated with the snail and slug hosts of Angiostrongylus cantonensis with three common household solutions.

    PubMed

    Yeung, Norine W; Hayes, Kenneth A; Cowie, Robert H

    2013-06-01

    The emerging infectious disease angiostrongyliasis (rat lungworm disease) is caused by ingesting snails and slugs infected by the nematode Angiostrongylus cantonensis. The definitive hosts of A. cantonensis are rats and the obligatory intermediate hosts are slugs and snails. Many cases result from accidentally ingesting infected snails or slugs on produce (eg, lettuce). This study assessed three readily available household products as washing solutions for removing snails and slugs from produce (romaine lettuce) to lower the probability of accidentally ingesting them. The solutions were acetic acid (vinegar), sodium hypochlorite (bleach), and sodium chloride (domestic salt). Snail and slug species known to be intermediate hosts and that are common in the Hawaiian Islands were used in the experiments: the alien snail Succinea tenella, the alien semi-slug Parmarion martensi, and the alien slugs Veronicella cubensis and Deroceras laeve. None of the products was any more effective than washing and rinsing with tap water alone. Most snails and slugs were removed after treatment but some remained on the lettuce even after washing and rinsing the produce. Only washing, rinsing, and then rinsing each leaf individually resulted in complete removal of all snails and slugs. The study did not address removal of any remaining slime left by the snails and slugs, nor did it address killing of worms.

  5. Ultrasound and physical models shed light on the respiratory system of embryonic dogfishes.

    PubMed

    Tomita, Taketeru; Cotton, Charles F; Toda, Minoru

    2016-02-01

    Embryos of live-bearing elasmobranchs (sharks, skates, and rays) must acquire oxygen in the uterus for several months to more than a year, but the mechanisms of delivery and uptake are still largely unknown. Diagnostic sonography performed on a captive Japanese dogfish (Squalus japonicus) showed that a late-stage embryo used buccal movement to pump uterine fluid, suggesting that the embryo acquires oxygen from uterine fluid via gill ventilation. It has been assumed that embryonic respiration in aplacental sharks depends on oxygen supplied by the uterine wall. To test this hypothesis, the rate of oxygen diffusion was estimated by applying a physical model to the uterine wall of two dogfish species (Squalus cf. mitsukurii and Squalus cubensis). The model calculations indicate that the supply of oxygen via diffusion through the uterine villi contributes less than 15-30% of the total oxygen demand of late-stage embryos. Some previous authors have suggested that pregnant dogfish intermittently exchange uterine fluid with external seawater during late gestation. Thus, late-stage embryos may acquire oxygen primarily from uterine seawater introduced from the external environment. Copyright © 2015 Elsevier GmbH. All rights reserved.

  6. Validation of a portable, waterproof blood pH analyser for elasmobranchs.

    PubMed

    Talwar, Brendan; Bouyoucos, Ian A; Shipley, Oliver; Rummer, Jodie L; Mandelman, John W; Brooks, Edward J; Grubbs, R Dean

    2017-01-01

    Quantifying changes in blood chemistry in elasmobranchs can provide insights into the physiological insults caused by anthropogenic stress, and can ultimately inform conservation and management strategies. Current methods for analysing elasmobranch blood chemistry in the field are often costly and logistically challenging. We compared blood pH values measured using a portable, waterproof pH meter (Hanna Instruments HI 99161) with blood pH values measured by an i-STAT system (CG4+ cartridges), which was previously validated for teleost and elasmobranch fishes, to gauge the accuracy of the pH meter in determining whole blood pH for the Cuban dogfish (Squalus cubensis) and lemon shark (Negaprion brevirostris). There was a significant linear relationship between values derived via the pH meter and the i-STAT for both species across a wide range of pH values and temperatures (Cuban dogfish: 6.8-7.1 pH 24-30°C; lemon sharks: 7.0-7.45 pH 25-31°C). The relative error in the pH meter's measurements was ~±2.7%. Using this device with appropriate correction factors and consideration of calibration temperatures can result in both a rapid and accurate assessment of whole blood pH, at least for the two elasmobranch species examined here. Additional species should be examined in the future across a wide range of temperatures to determine whether correction factors are universal.

  7. Synthesis and biological evaluation of novel fluorine-containing stilbene derivatives as fungicidal agents against phytopathogenic fungi.

    PubMed

    Jian, Weilin; He, Daohang; Xi, Pinggen; Li, Xinwei

    2015-11-18

    The rising development of resistance to conventional fungicides is driving the search for new alternative candidates to control plant diseases. In this study, a series of new fluorine-containing stilbene derivatives was synthesized on the basis of our previous quantitative structure-activity relationship analysis results. Bioassays in vivo revealed that the title compounds exhibited potent fungicidal activities against phytopathogenic fungi (Colletotrichum lagenarium and Pseudoperonospora cubensis) from cucumber plants. In comparison to the previous results, the introduction of a fluorine moiety showed improved activities of some compounds against those fungi. Notably, compound 9 exhibited a control efficacy against C. lagenarium (83.4 ± 1.3%) comparable to that of commercial fungicide (82.7 ± 1.7%). For further understanding the possible mode of action of the stilbene against C. lagenarium, the effects on hyphal morphology, electrolyte leakage, and respiration of mycelial cell suspension were studied. Microscopic observation showed considerably deformed mycelial morphology. The conductivity of mycelial suspension increased in the presence of compound 9, whereas no significantly inhibitory effect on respiration was observed. Taken together, the fungicidal mechanism of this stilbene is associated with its membrane disruption effect, resulting in increased membrane permeability. These results provide important clues for mechanistic study and derivatization of stilbenes as alternative sources of fungicidal agents for plant disease control.

  8. Cucumber disease diagnosis using multispectral images

    NASA Astrophysics Data System (ADS)

    Feng, Jie; Li, Hongning; Shi, Junsheng; Yang, Weiping; Liao, Ningfang

    2009-07-01

    In this paper, multispectral imaging technique for plant diseases diagnosis is presented. Firstly, multispectral imaging system is designed. This system utilizes 15 narrow-band filters, a panchromatic band, a monochrome CCD camera, and standard illumination observing environment. The spectral reflectance and color of 8 Macbeth color patches are reproduced between 400nm and 700nm in the process. In addition, spectral reflectance angle and color difference is obtained through measurements and analysis of color patches using spectrometer and multispectral imaging system. The result shows that 16 narrow-bands multispectral imaging system realizes good accuracy in spectral reflectance and color reproduction. Secondly, a horticultural plant, cucumber' familiar disease are the researching objects. 210 multispectral samples are obtained by multispectral and are classified by BP artificial neural network. The classification accuracies of Sphaerotheca fuliginea, Corynespora cassiicola, Pseudoperonospora cubensis are 100%. Trichothecium roseum and Cladosporium cucumerinum are 96.67% and 90.00%. It is confirmed that the multispectral imaging system realizes good accuracy in the cucumber diseases diagnosis.

  9. Synthesis of 1,2,3-Thiadiazole and Thiazole-Based Strobilurins as Potent Fungicide Candidates.

    PubMed

    Chen, Lai; Zhu, Yu-Jie; Fan, Zhi-Jin; Guo, Xiao-Feng; Zhang, Zhi-Ming; Xu, Jing-Hua; Song, Ying-Qi; Yurievich, Morzherin Y; Belskaya, Nataliya P; Bakulev, Vasiliy A

    2017-02-01

    Strobilurin fungicides play a crucial role in protecting plants against different pathogens and securing food supplies. A series of 1,2,3-thiadiazole and thiazole-based strobilurins were rationally designed, synthesized, characterized, and tested against various fungi. Introduction of 1,2,3-thiadiazole greatly improved the fungicidal activity of the target molecules. Compounds 8a, 8c, 8d, and 10i exhibited a relatively broad spectrum of fungicidal activity. Compound 8a showed excellent activities against Gibberella zeae, Sclerotinia sclerotiorum, and Rhizoctonia cerealis with median effective concentrations (EC50) of 2.68, 0.44, and 0.01 μg/mL, respectively; it was much more active than positive controls enestroburin, kresoxim-methyl, and azoxystrobin with EC50 between 0.06 and 15.12 μg/mL. Comparable or better fungicidal efficacy of compound 8a compared with azoxystrobin and trifloxystrobin against Sphaerotheca fuliginea and Pseudoperonspera cubensis was validated in cucumber fields at the same application dosages. Therefore, compound 8a is a promising fungicidal candidate worthy of further development.

  10. Isolation and characterization of an antifungal protein from Bacillus licheniformis HS10.

    PubMed

    Wang, Zhixin; Wang, Yunpeng; Zheng, Li; Yang, Xiaona; Liu, Hongxia; Guo, Jianhua

    2014-11-07

    Bacillus licheniformis HS10 is a good biocontrol agent against Pseudoperonospora cubensis which caused cucumber downy disease. To identify and characterize the antifungal proteins produced by B.licheniformis HS10, the proteins from HS10 were isolated by using 30-60% ammonium sulfate precipitation, and purified with column chromatography on DEAE Sepharose Fast Flow, RESOURCE Q and Sephadex G-75. And the SDS-PAGE and MALDI-TOF/TOF-MS analysis results demonstrated that the antifungal protein was a monomer with molecular weight of about 55 kDa, identified as carboxypeptidase. Our experiments also showed that the antifungal protein from B. licheniformis HS10 had significantly inhibition on eight different kinds of plant pathogenic fungi, and it was stable with good biological activity at as high as 100°C for 30 min and in pH value ranged from 6 to 10. The biological activity was negatively affected by protease K and 10mM metal cations except Ca(2+).

  11. Neogene sharks and rays from the Brazilian 'Blue Amazon'.

    PubMed

    Aguilera, Orangel; Luz, Zoneibe; Carrillo-Briceño, Jorge D; Kocsis, László; Vennemann, Torsten W; de Toledo, Peter Mann; Nogueira, Afonso; Amorim, Kamilla Borges; Moraes-Santos, Heloísa; Polck, Marcia Reis; Ruivo, Maria de Lourdes; Linhares, Ana Paula; Monteiro-Neto, Cassiano

    2017-01-01

    The lower Miocene Pirabas Formation in the North of Brazil was deposited under influence of the proto-Amazon River and is characterized by large changes in the ecological niches from the early Miocene onwards. To evaluate these ecological changes, the elasmobranch fauna of the fully marine, carbonate-rich beds was investigated. A diverse fauna with 24 taxa of sharks and rays was identified with the dominant groups being carcharhiniforms and myliobatiforms. This faunal composition is similar to other early Miocene assemblages from the proto-Carribbean bioprovince. However, the Pirabas Formation has unique features compared to the other localities; being the only Neogene fossil fish assemblage described from the Atlantic coast of Tropical Americas. Phosphate oxygen isotope composition of elasmobranch teeth served as proxies for paleotemperatures and paleoecology. The data are compatible with a predominantly tropical marine setting with recognized inshore and offshore habitats with some probable depth preferences (e.g., Aetomylaeus groups). Paleohabitat of taxa particularly found in the Neogene of the Americas (†Carcharhinus ackermannii, †Aetomylaeus cubensis) are estimated to have been principally coastal and shallow waters. Larger variation among the few analyzed modern selachians reflects a larger range for the isotopic composition of recent seawater compared to the early Miocene. This probably links to an increased influence of the Amazon River in the coastal regions during the Holocene.

  12. Taxonomic revision of Rochefortia Sw. (Ehretiaceae, Boraginales)

    PubMed Central

    Irimia, Ramona-Elena

    2016-01-01

    Abstract Background Rochefortia is a small taxon of woody plants in the Ehretiaceae (Boraginales) exhibiting coriaceous leaves with cystoliths, small whitish flowers and drupaceous fruits containing four pyrenes. It shares the dioecious sex distribution with its sister group Lepidocordia and can be delimited from the latter (and all other Ehretiaceae) by the presence of thorns. Neotropical Rochefortia is distributed over most Caribbean islands, Central America and northern South America. Twenty-eight validly published names (corresponding to twenty-one typified taxa at the species level and below) are available in Rochefortia, but the precise number of species to be accepted has been elusive before this revision. New information In the course of the present revision, 353 herbarium collections, comprising approximately 540 Rochefortia specimens, were entried into a BRAHMS data base providing information about protologues and types and retrospective georeferences if possible. Based on the combination of molecular and morphological data we propose to recognise nine species of Rochefortia, namely R. acanthophora, R. bahamensis, R. barloventensis, R. cubensis, R. cuneata, R. lundellii, R. oblongata, R. spinosa and R. stellata (the remaining nineteen validly published names are synonymised under such names). Morphological description of each species and an identification key are provided. PMID:27346952

  13. Species diversity in the Antrodia crassa group (Polyporales, Basidiomycota).

    PubMed

    Spirin, Viacheslav; Runnel, Kadri; Vlasák, Josef; Miettinen, Otto; Põldmaa, Kadri

    2015-12-01

    Antrodia is a polyphyletic genus, comprising brown-rot polypores with annual or short-lived perennial resupinate, dimitic basidiocarps. Here we focus on species that are closely related to Antrodia crassa, and investigate their phylogeny and species delimitation using geographic, ecological, morphological and molecular data (ITS and LSU rDNA, tef1). Phylogenetic analyses distinguished four clades within the monophyletic group of eleven conifer-inhabiting species (five described herein): (1)A. crassa s. str. (boreal Eurasia), Antrodia cincta sp. nova (North America) and Antrodia cretacea sp. nova (holarctic), all three being characterized by inamyloid skeletal hyphae that dissolve quickly in KOH solution; (2) Antrodia ignobilis sp. nova, Antrodia sitchensis and Antrodia sordida from North America, and Antrodia piceata sp. nova (previously considered conspecific with A. sitchensis) from Eurasia, possessing amyloid skeletal hyphae; (3) Antrodia ladiana sp. nova from the southern part of the USA, Antrodia pinea from East Asia, and Antrodia ferox - so far known from subtropical North America, but here reported also from Eurasia. These three species have inamyloid hyphae and narrow basidiospores; (4) the North American Antrodia pini-cubensis, sharing similar morphological characters with A. pinea, forming a separate clade. The habitat data indicate that several species are threatened by intensive forestry.

  14. Protease activity in cockroach and basidiomycete allergen extracts.

    PubMed

    Wongtim, S; Lehrer, S B; Salvaggio, J E; Horner, W E

    1993-01-01

    Inherent proteolytic activity was estimated in cockroach and basidiomycete extracts by quantifying acid soluble peptides that were released by incubating extracts with 1% bovine serum albumin as measured by Lowry (Sigma). Reference proteases released 740 (Proteinase K, 0.1 U), 248 (Trypsin, 1.0 U), and 533 micrograms/ml (Pronase, 0.5 U) of soluble peptides. American whole body cockroach extract (0.1 mg dry weight) released 330 micrograms/ml of soluble peptides, representing 13 trypsin equivalent units (TEU)/mg. Extracts from spores of the mushroom Pleurotus ostreatus released 230 micrograms/ml (0.9 TEU/mg) and Pleurotus cap extract released 112 micrograms/ml (0.5 TEU/mg). Mycelium of Pleurotus and the mushroom Psilocybe cubensis and spores of Psilocybe and the puffball Calvatia cyathiformis showed negligible amounts of proteolytic activity. The protease inhibitor phenylmethylsulfonyl flouride reduced the proteolytic activity of American whole body cockroach extract by 80% (@1 mM) and the inhibitor ethylene diaminetetraacetic acid inhibited the proteolytic activity of Pleurotus spores by 95% (@1 mM). Loss of allergen activity as determined by RAST inhibition and immunoprinting correlated with protease activity. Thus, in the preparation and handling of allergen extracts, one should employ conditions that minimize proteolysis.

  15. Bilateral symmetry in crayfish behavioral reactions.

    PubMed

    Shuranova, Zhanna

    2008-01-01

    The crayfish, Procambarus cubensis, placed in the central area of a plus-maze preferred to go forward in about 50% of trials; they chose the right or left arm in 20.7 and 18.9% of the trials, respectively. In a T-maze, the difference between right and left directions was also insignificant. When exploring a plus-maze, the crayfish turned to 180 degrees at the end of the arms, then turned to 90 degrees going to the next arm. The mean difference between the right and left U-turns, and the right and left turns was insignificant though some animals demonstrated a left or right preference. There was a strong correlation between the direction of U-turns and following turns ensuring the clockwise or anti-clockwise movements of the crayfish. Also we examined a possible preference of the right or left claw in the feeding behavior of the crayfish. The crayfish caught a small bloodworm given from above equally with the right or left claw. The crayfish conditioned to take a bloodworm with a claw did not demonstrate any stable preference of left or right claw in the course of the experiments. The question of bilateral asymmetries within the decapod crustaceans is discussed.

  16. Neogene sharks and rays from the Brazilian ‘Blue Amazon’

    PubMed Central

    Aguilera, Orangel; Carrillo-Briceño, Jorge D.; Kocsis, László; Vennemann, Torsten W.; de Toledo, Peter Mann; Nogueira, Afonso; Amorim, Kamilla Borges; Moraes-Santos, Heloísa; Polck, Marcia Reis; Ruivo, Maria de Lourdes; Linhares, Ana Paula; Monteiro-Neto, Cassiano

    2017-01-01

    The lower Miocene Pirabas Formation in the North of Brazil was deposited under influence of the proto-Amazon River and is characterized by large changes in the ecological niches from the early Miocene onwards. To evaluate these ecological changes, the elasmobranch fauna of the fully marine, carbonate-rich beds was investigated. A diverse fauna with 24 taxa of sharks and rays was identified with the dominant groups being carcharhiniforms and myliobatiforms. This faunal composition is similar to other early Miocene assemblages from the proto-Carribbean bioprovince. However, the Pirabas Formation has unique features compared to the other localities; being the only Neogene fossil fish assemblage described from the Atlantic coast of Tropical Americas. Phosphate oxygen isotope composition of elasmobranch teeth served as proxies for paleotemperatures and paleoecology. The data are compatible with a predominantly tropical marine setting with recognized inshore and offshore habitats with some probable depth preferences (e.g., Aetomylaeus groups). Paleohabitat of taxa particularly found in the Neogene of the Americas (†Carcharhinus ackermannii, †Aetomylaeus cubensis) are estimated to have been principally coastal and shallow waters. Larger variation among the few analyzed modern selachians reflects a larger range for the isotopic composition of recent seawater compared to the early Miocene. This probably links to an increased influence of the Amazon River in the coastal regions during the Holocene. PMID:28832664

  17. [Distribution and ecological characteristics of freshwater snails of medical importance in Santiago de Cuba province].

    PubMed

    Vázquez Perera, Antonio Alejandro; González Coello, Carelia; Sánchez Noda, Jorge; Alba Menéndez, Annia

    2011-01-01

    The ability of freshwater snails to serve as intermediary host of parasites responsible for some tropical diseases is well known. A malacological study was carried out in the Santiago de Cuba province in order to determine the distribution of freshwater snails of medical importance and their relation with the main ecosystems. Nineteen sites were sampled in the province and the abundance of each of the species was compared to the type of habitat by means of the correspondence analysis. Each site was referred from the geographical viewpoint to determine the distribution patterns. A total amount of 12 freshwater snail species was found and the most abundant were Tarebia granifera, Physa acuta and Pyrgophorus parvulus. Rivers are the main types of ecosystems associated to these species followed by springs and ditches. Fossaria cubensis showed high density in flooded grounds whereas Biomphalaria pallida was the only planorbid species that could coexist with thiarid species. Due to the species found in this province, the likelihood of possible outbreaks of fasciolosis as well as the introduction of schistosomiasis is considered as high.

  18. Synoptic revision of Blabericola (Apicomplexa: Eugregarinida: Blabericolidae) parasitizing blaberid cockroaches (Dictyoptera: Blaberidae), with comments on delineating gregarine species boundaries.

    PubMed

    Clopton, Richard E

    2012-06-01

    Complete synoptic redescriptions, including complete morphometric data for all life cycle stages, species recognition characters, and differential comparisons are presented for the 4 gregarine species comprising Blabericola . Blabericola cubensis ( Peregrine, 1970 ), Blabericola haasi (Geus, 1969), Blabericola migrator ( Clopton, 1995 ), and Blabericola princisi ( Peregrine, 1970 ) are redescribed from their type hosts, i.e., the discoid cockroach Blaberus discoidalis , the lobster cockroach Nauphoeta cinerea , the Madagascar hissing cockroach Gromphadorhina portentosa , and the Bolivian cockroach Blaberus boliviensis , respectively. These gregarine species descriptions are stabilized through deposition of extensive new voucher collections. Species of Blabericola are distinguished by differences in relative metric ratios, morphology of oocysts, and by relative metric ratios of mature gamonts in association. This work is discussed as a model for morphological species descriptions in the Eugregarinorida including the 6 principles for morphological gregarine species descriptions, i.e., a centroid and population variation approach, adequate sample size, partitioning developmental variation and sexual dimorphism, recognition and minimization of fixation and physiological artifacts to eliminate false morphotypes, and comparative data sets across multiple life cycle stages.

  19. Epicatechin, a component of dark chocolate, enhances memory formation if applied during the memory consolidation period.

    PubMed

    Fernell, Maria; Swinton, Cayley; Lukowiak, Ken

    2016-01-01

    Epicatechin (Epi), a flavanol found in foods such as dark chocolate has previously been shown to enhance memory formation in our model system, operant conditioning of aerial respiration in Lymnaea. In those experiments snails were trained in Epi. Here we ask whether snails exposed to Epi before training, during the consolidation period immediately following training, or 1 h after training would enhance memory formation. We report here that Epi is only able to enhance memory if snails are placed in Epi-containing pond water immediately after training. That is, Epi enhances memory formation if it is applied during the memory consolidation period as well as if snails are trained in Epi-containing pond water.

  20. Distribution of potential intermediate hosts for Fasciola hepatica and Fascioloides magna in Montana, USA.

    PubMed

    Dunkel, A M; Rognlie, M C; Johnson, G R; Knapp, S E

    1996-03-01

    A collection of lymnaeid snails in Montana was made over a 3 year period, in conjunction with a state-wide survey of the distribution of liver flukes in Montana. Collection areas were selected based on reports of infected cattle, sheep or wildlife, and with the intent of covering all geographic regions of the state. Snails were found at all 97 of the locations chosen for collections, with lymnaeids collected at 71 of the locations. The 97 sites were located in 28 of Montana's 56 counties. Nine lymnaeid species were collected, five of which have been reported either as natural or experimental intermediate hosts for Fasciola hepatica or Fascioloides magna. The two snail species most widely distributed over the areas enzootic for the flukes were Lymnaea modicella and Lymanaea caperata.

  1. Screening of some Nigerian plants for molluscicidal activity.

    PubMed

    Kela, S L; Ogunsusi, R A; Ogbogu, V C; Nwude, N

    1989-01-01

    Methanolic (MEOH), evaporated crude water (ECW) and unevaporated crude water (UECW) extracts of 25 Nigerian plants, used for different medicinal and domestic purposes were screened for molluscacidal activity on laboratory-reared Lymnaea natalensis Krauss. Seven of the plants were not active; extracts from 18 (72 per cent) of the plants, some of which are renowned fish poisons, had molluscicidal activity. These were Acacia nilotica, Aristolochia albida, Balanites aegyptiaca, Blighia sapida, Boswellia dalzielii, Detarium microcarpum, Gnidia kraussiana, Kigelia africana, Nauclea latifolia, Opilia celtidefolia, Parkia clappertoniana, Polygonum limbatum, Pseudocedrela kotschyi, Sclerocarya birrea, Securidaca longipedunculata, Ximenia americana, Vetiveria nigritana and Ziziphus abyssinica. The LC50 of these extracts were determined. It is strongly recommended that the toxic effects of these extracts against fish, cercariae, snail eggs and mammals be further investigated so as to determine the right concentration, especially for use in fish ponds.

  2. Molluscicidal activity of Lawsonia inermis and its binary and tertiary combinations with other plant derived molluscicides.

    PubMed

    Singh, A; Singh, D K

    2001-03-01

    Molluscicidal activity of leaf, bark and seed of Lawsonia inermis against Lymnaea acuminata and Indoplanorbis exustus was studied. Highest toxicity was observed in the seed of Lawsonia inermis. Toxicity of binary (1:1) and tertiary (1:1:1) combinations of the essential oil of cedar (Cedrus deodara Roxh) and neem (Azadirachta indica A. Juss), powder from bulb of garlic (Allium sativum Linn), and oleoresin extracted from rhizome of ginger (Zingiber officinale Rosc) with Lawsonia inermis and Embelia ribes fruit powder were studied against L. acuminata and I. exustus. L. inermis seed powder in combination with Cedrus deodara oil and Azadirachta indica oil was more toxic than their individual components and other combinations.

  3. Effect of different combinations of MGK-264 or piperonyl butoxide with plant-derived molluscicides on snail reproduction.

    PubMed

    Singh, K; Singh, D K

    2000-02-01

    Effect of sublethal treatment (20% and 60% of LC(50)/24 h) of plant-derived molluscicides, viz. Polianthes tuberosa, Trachyspermum ammi, Allium sativum powder; Azadirachta indica oil; oleoresin of Zingiber officinale; and their active molluscicidal component in combination (1:5) with MGK-264 or piperonyl butoxide on the reproduction of snail Lymnaea acuminata have been studied. It was observed that the combination of plant derived molluscicide and their active molluscicidal components, viz. tigogenin, hecogenin, azadirachtin, allicin, thymol, and [6]-gingerol combination with MGK-264 or piperonyl butoxide caused a significant reduction in fecundity, hatchability, and survival of young snails. Withdrawal of snails to fresh water after the above treatment caused a significant recovery in the fecundity of L. acuminata.

  4. Echinostoma friedi: the effect of age of adult worms on the infectivity of miracidia.

    PubMed

    Toledo, R; Espert, A; Carpena, I; Trelis, M; Muñoz-Antoli, C; Esteban, J G

    2004-03-01

    The effect of ageing of adults of Echinostoma friedi (Trematoda: Echinostomatidae) on the infectivity of miracidia yielded was analysed. Miracidia were obtained after hatching of eggs obtained from adult worms of E. friedi collected weekly during the course of experimental infections in golden hamsters. Miracidial infectivity, measured in terms of percentage of infection in Lymnaea peregra, was significantly influenced by the age of the adult worms from which the miracidia were derived. Infective miracidia only were obtained from adult worms in the age range from 4 to 9 weeks post-infection. Infectivity was maximal in those miracidia derived from adults collected 8 and 9 weeks post-infection. The results suggest that adult worms producing viable eggs require additional maturation to be able to yield eggs containing infective miracidia.

  5. The life cycle and transmission dynamics of the larval stages of Hypoderaeum conoideum.

    PubMed

    Muñoz-Antolí, C; Toledo, R; Esteban, J G

    2000-06-01

    The morphology of the different larval stages and life cycle of Hypoderaeum conoideum (Trematoda: Echinostomatidae) are described. The freshwater snail species Lymnaea peregra (Gastropoda: Lymnaeidae) serves as the natural first intermediate host and this and L. corvus serve as experimental first intermediate hosts. These and other freshwater snails, such as Physella acuta and Gyraulus chinensis, in turn serve as second intermediate hosts. Adult worms were obtained from chicks and ducks, but not from rats, mice and golden hamsters. The morphology of the larval stages is compared with previous work on H. conoideum. Several aspects of the biology of the life history stages are described with emphasis on the transmission dynamics of the free-living stages. Differential suitability of the snail species that may act as first and/or second intermediate hosts is studied and discussed.

  6. Effects of Aβ exposure on long-term associative memory and its neuronal mechanisms in a defined neuronal network.

    PubMed

    Ford, Lenzie; Crossley, Michael; Williams, Thomas; Thorpe, Julian R; Serpell, Louise C; Kemenes, György

    2015-05-29

    Amyloid beta (Aβ) induced neuronal death has been linked to memory loss, perhaps the most devastating symptom of Alzheimer's disease (AD). Although Aβ-induced impairment of synaptic or intrinsic plasticity is known to occur before any cell death, the links between these neurophysiological changes and the loss of specific types of behavioral memory are not fully understood. Here we used a behaviorally and physiologically tractable animal model to investigate Aβ-induced memory loss and electrophysiological changes in the absence of neuronal death in a defined network underlying associative memory. We found similar behavioral but different neurophysiological effects for Aβ 25-35 and Aβ 1-42 in the feeding circuitry of the snail Lymnaea stagnalis. Importantly, we also established that both the behavioral and neuronal effects were dependent upon the animals having been classically conditioned prior to treatment, since Aβ application before training caused neither memory impairment nor underlying neuronal changes over a comparable period of time following treatment.

  7. Biosynthesis of galactogen: purification of a 1. -->. 6 D-galactosyltransferase from Helix pomatia

    SciTech Connect

    Goudsmit, E.M.

    1986-05-01

    A (1 ..-->.. 6) D-galactosyltransferase from a pellet fraction (8000xg) of Helix pomatia albumen gland has been purified over 2000-fold by affinity chromatography on UDP-p-amino-phenyl-Sepharose. The enzyme catalyzes transfer of D-galactose from UDP-galactose to a 1 ..-->.. 6 linkage on acceptor H. pomatia galactogen. Three other polymers served as acceptors; beef lung galactan, Lymnaea stagnalis galactogen and arabinogalactan from larch wood. To determine the linkage of added galactose termini, acceptor galactogen of H. pomatia that had been tritiated by treatment with galactose oxidase and (/sup 3/H)KBH/sub 4/ was incubated with UDP-D-galactose and purified enzyme extract. /sup 3/H-galactogen reaction product was recovered, methylated, hydrolyzed and acetylated; tritiated derivatives were identified by collection of effluent fractions from gas chromatography.

  8. Prolonged modification of action potential shape by synaptic inputs in molluscan neurones.

    PubMed

    Winlow, W

    1985-01-01

    1. Somatic action potentials of Lymnaea neurons are modified by excitatory or inhibitory synaptic inputs and have been studied using phase-plane techniques and an action potential duration monitor. 2. Excitatory synaptic inputs increase the rate of neuronal discharge, cause action potential broadening, a decrease in the maximum rate of depolarization (Vd) and a decrease in the maximum rate of repolarization (Vr). 3. Inhibitory synaptic inputs decrease the discharge rate and cause narrowing of action potentials, an increase in Vd and an increase in Vr. 4. The effects reported above outlast the original synaptic inputs by many seconds and, if the somatic action potentials are similar to those in the axon terminals, they may have far-reaching effects on transmitter release.

  9. A novel, nongenomic mechanism underlies retinoic acid-induced growth cone turning.

    PubMed

    Farrar, Nathan R; Dmetrichuk, Jennifer M; Carlone, Robert L; Spencer, Gaynor E

    2009-11-11

    The vitamin A metabolite, retinoic acid (RA), is well known for its roles in neural development and regeneration. We have previously shown that RA can induce positive growth cone turning in regenerating neurons in vitro. In this study, we address the subcellular mechanisms underlying this chemo-attractive response, using identified central neurons from the adult mollusc, Lymnaea stagnalis. We show that the RA-induced positive growth cone turning was maintained in the presence of the transcriptional inhibitor, actinomycin D. We also physically transected the neurites from the cell body and showed that isolated growth cones retain the capacity to turn toward a gradient of RA. Moreover, this attractive turning is dependent on de novo local protein synthesis and Ca(2+) influx. Most of RA's actions during neurite outgrowth and regeneration require gene transcription, although these data show for the first time in any species, that the chemotropic action of RA in guiding neurite outgrowth, involves a novel, nongenomic mechanism.

  10. Receipt of seminal fluid proteins causes reduction of male investment in a simultaneous hermaphrodite.

    PubMed

    Nakadera, Yumi; Swart, Elferra M; Hoffer, Jeroen N A; den Boon, Onno; Ellers, Jacintha; Koene, Joris M

    2014-04-14

    Mating partners often have conflicting interests when copulating. One of the major agents affecting female mating partners is seminal fluid, transferred along with sperm. The role of seminal fluid proteins (SFPs) in reproductive success is well studied in separate-sexed animals but is much less so in simultaneous hermaphrodites. The latter potentially have a unique target to exploit for the sperm donor's own benefit: the male function of their mating partners. Here we show that, in the great pond snail Lymnaea stagnalis, receipt of specific SFPs reduces both sperm transfer and paternity success in a subsequent insemination event. Lowering investment in the mating partner's male function constitutes a novel role for SFPs. This demonstrates for the first time that hermaphrodites alter their mates' male as well as female reproductive output. Although it remains to be tested whether this represents mate manipulation or an adaptive response of recipients, our findings identify male investment as a new target for postcopulatory sexual selection.

  11. Liver fluke disease (fascioliasis): epidemiology, economic impact and public health significance.

    PubMed

    Saleha, A A

    1991-12-01

    Liver fluke disease (fascioliasis) is an important parasitic disease found worldwide affecting sheep, goats, cattle and buffalo, as well as other domestic ruminants. The common causative agents are Fasciola hepatica and F. gigantica which require various species of Lymnaea, fresh water snails, as their intermediate hosts. The epidemiology of the disease and its prevalence in Malaysia is mentioned briefly. The disease causes considerable impact on the economy of the livestock industry. The economic losses consist of costs of anthelmintics, drenches, labor, liver condemnation at meat inspection; and losses in production due to mortality, reduction in meat, milk and wool production; and reduction in growth rate, fertility and draught power. The disease also has public health significance, causing human fascioliasis and "halzoun".

  12. Epicatechin, a component of dark chocolate, enhances memory formation if applied during the memory consolidation period

    PubMed Central

    Fernell, Maria; Swinton, Cayley; Lukowiak, Ken

    2016-01-01

    ABSTRACT Epicatechin (Epi), a flavanol found in foods such as dark chocolate has previously been shown to enhance memory formation in our model system, operant conditioning of aerial respiration in Lymnaea. In those experiments snails were trained in Epi. Here we ask whether snails exposed to Epi before training, during the consolidation period immediately following training, or 1 h after training would enhance memory formation. We report here that Epi is only able to enhance memory if snails are placed in Epi-containing pond water immediately after training. That is, Epi enhances memory formation if it is applied during the memory consolidation period as well as if snails are trained in Epi-containing pond water. PMID:27574544

  13. Male Accessory Gland Protein Reduces Egg Laying in a Simultaneous Hermaphrodite

    PubMed Central

    Koene, Joris M.; Sloot, Wiebe; Montagne-Wajer, Kora; Cummins, Scott F.; Degnan, Bernard M.; Smith, John S.; Nagle, Gregg T.; ter Maat, Andries

    2010-01-01

    Seminal fluid is an important part of the ejaculate of internally fertilizing animals. This fluid contains substances that nourish and activate sperm for successful fertilization. Additionally, it contains components that influence female physiology to further enhance fertilization success of the sperm donor, possibly beyond the recipient's optimum. Although evidence for such substances abounds, few studies have unraveled their identities, and focus has been exclusively on separate-sex species. We present the first detailed study into the seminal fluid composition of a hermaphrodite (Lymnaea stagnalis). Eight novel peptides and proteins were identified from the seminal-fluid-producing prostate gland and tested for effects on oviposition, hatching and consumption. The gene for the protein found to suppress egg mass production, Ovipostatin, was sequenced, thereby providing the first fully-characterized seminal fluid substance in a simultaneous hermaphrodite. Thus, seminal fluid peptides and proteins have evolved and can play a crucial role in sexual selection even when the sexes are combined. PMID:20404934

  14. Interaction of neurons at the level of cell bodies in the snail CNS. Heterogeneity of the neuroactive environment.

    PubMed

    Chistopol'skii, I A

    2005-09-01

    Experiments on the CNS of snail Lymnaea stagnalis in which a cell isolated from the serotonin cluster PeA was used as a mobile sensor neuron demonstrated the presence of neuroactive factors at the surface of the cellular "cortex" of the pedal ganglion. Apart from the previously known factor serotonin, effective concentrations of a factor suppressing the electrical activity of PeA were found at this site, along with a depolarizing factor which, unlike serotonin, narrowed PeA action potentials. The ability of these factors to control the electrical activity of the sensor neuron demonstrates the possible involvement of chemical agents in the intercellular space of the "cortex" in neuronal signaling.

  15. A flavanoid component of chocolate quickly reverses an imposed memory deficit.

    PubMed

    Knezevic, Bogdan; Komatsuzaki, Yoshimasa; de Freitas, Emily; Lukowiak, Ken

    2016-03-01

    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.

  16. [Epidemiological data on human distomatosis (Fasciola hepatica L.) in the Limousin region of France. The species of plants eaten and snail hosts].

    PubMed

    Rondelaud, D

    1980-01-01

    These epidemiological studies concern 187 cases of human fasciolasis which occurred in the region of Limousin, France on a period of 24 years. Four species of plants have been eaten: Nasturtium officinale, Roripa silvestris, Taraxacum gr. officinale, Valerianella olitoria. These plants have been eaten during all months of the year, but with higher numbers in July-August and from November to February. The cases of human fasciolasis almost take place on all years, but their numbers are high in years showing a very important infestation of cattle by Fasciola hepatica. In 2/3 of cases, the plants come from stations situated out of cattle pastures. The water-cress almost comes from natural stations or from familial plantations. Five species of snails have been observed in these stations: Lymnaea glabra, L. palustris, L. peregra, L. stagnalis, L. truncatula. The young snails of these species experimentally have been observed. The significance of these results is discussed.

  17. Sensitivity of midge larvae of Chironomus tentans Fabricius (Diptera Chironomidae) to heavy metals

    SciTech Connect

    Khangarot, B.S.; Ray, P.K.

    1989-03-01

    The discharge of heavy metals into the natural waters has numerous obvious impacts on physical, chemical and biological parameters of aquatic ecosystem. Bioassay tests are important steps in establishing appropriate water quality criteria and standards for diverse use of ponds, lakes, streams and river waters. Therefore, the acute toxicities of various heavy metals to water flea Daphnia magna, and snail Lymnaea acuminata, and toad tadpoles Bufo mentanostictus have been reported from the authors' laboratory. Chironomid larvae might be particularly useful as indicators of water quality because they are widely distributed in freshwater systems and often from diverse communities within particular habitat. The aim of this study was to determine the acute toxicity of ten heavy metals to the midge larvae Chironomus tentans Fabricius, which forms an important link in aquatic food chain(s).

  18. Toxicity of anti-fouling biocides to encysted metacercariae of Echinoparyphium recurvatum (Digenea: Echinostomatidae) and their snail hosts.

    PubMed

    Morley, N J; Leung, K M Y; Morritt, D; Crane, M

    2004-07-01

    The toxicity of the anti-fouling biocides tributyltin (TBTO), copper, and Irgarol 1051 (irgarol) at a nominal concentration of 10 microg/l over a 30 day period were investigated against the viability of metacercarial cysts of the digenean parasite Echinoparyphium recurvatum resident within the body of two common freshwater snails, Lymnaea peregra and Physa fontinalis. Reduced parasite viability was found under most exposures in both snail species. However a greater effect of toxicant exposure was found in cysts within P. fontinalis compared to those in L. peregra. This was associated with an increased mortality of the host snail. Among all tested biocides, TBTO exposures induced the highest mortality to both the parasite and their hosts. These results suggest that parasite viability is interlinked with survival of the host snail. The mechanisms of differing toxicity between host species and its relevance to successful parasite transmission to the next host are discussed.

  19. [Controlled cell cultivation. V. The effect of various rubbers on the isolated neurons of Limnaea stagnalis in culture].

    PubMed

    Arkhipov, V V; Lezhnev, E I

    1980-08-01

    Various domestic rubbers were tested for toxicity to cultured isolated neurons of Lymnaea stagnalis, the survival time of these cells, and their morphological differentiation being used as criteria. According to the effect towards the neurons, the tested materials could be divided into inert, low-toxic, and toxic ones. Type 52336/4 silicon rubber, the rubber of surgical gloves, and dry rubber of "b" type produce no unfavourable effect on isolated neurons. Stoppers of penicillin bottles, baby's dummies, and silicon-based BgO-1 "Germetic" paste are low-toxic rubbers. By contrast, silicon rubbers of 52336 and 14p-6 types, KLT-30 silicon paste and black rubber of HO-68-1 type decreased sharply the survival time of the neurons and depressed their morphological differentiation in culture.

  20. Comparative studies on ecotoxicology of synthetic detergents.

    PubMed

    Lal, H; Misra, V; Viswanathan, P N; Krishna Murti, C R

    1983-12-01

    To predict the comparative toxicological response of synthetic detergents on aquatic ecosystems, the effects of various concentrations of neutralized alkyl benzene sulfonate were studied. The median tolerance limit at 48 hr, 95% confidence limit, slope function, presumable harmless concentration, and rate of survival of different species of aquatic fauna such as water fleas (Daphnia magna), mosquito larvae (Culex pipiens), slug worms (Tubifex rivulorum), snails (Lymnaea vulgaris), tadpoles (Rana cyanophlyctis), and fish fingerlings (Cirrhina mrigala) were followed at 0, 24, 48, 72, and 96 hr. Any effect on quality of the water was also tested after the addition of various concentrations of detergents. The results showed that water fleas are more susceptible to detergent toxicity than fish fingerlings, tadpoles, slug worms, snails, and mosquito larvae. Behavioral changes were also observed as an index for detergent toxicity. The relative toxicity of the detergents to various species is discussed in relation to selective ecotoxicological response.

  1. Experimental infections with Fasciola in snails, mice and rabbits.

    PubMed

    Hussein, Abdel-Nasser A; Khalifa, R M A

    2008-05-01

    Experimental infection trails of Lymnaea (cailliaudi) natalensis snails with miracidia of Fasciola hepatica revealed neither cercariae nor larval stages shed. Infection of white mice with metacercariae from field-collected snails proved to be negative for Fasciola eggs and immature juveniles or adults after 84 days post infection. The infection of eight rabbits (Oryctolagus cuniculus) has succeeded; two rabbits were infected, with a very low infection rate. Faeces of rabbits were negative for eggs. The worm burden was one and three worms from 40 fed metacercariae. The obtained fluke measures 23 mm in length by 4 mm in width. The tegument is covered with sharp-ending spines. The uterus contains few eggs. The intrauterine eggs measured 158 microm x 80 microm. According to the morphological characters of these flukes, they belong to F. gigantica.

  2. Detection of Fasciola gigantica infection in snails by polymerase chain reaction.

    PubMed

    Velusamy, R; Singh, B P; Raina, O K

    2004-02-26

    Polymerase chain reaction (PCR) was used to detect Fasciola gigantica infection in the snail intermediate host. Fasciola specific primers amplified a 124 bp fragment in PCR when the genomic DNA isolated from F. gigantica infected Lymnaea auricularia snails was used as template. In addition to the 124 bp amplicon, a ladder of DNA fragments representing amplification of the 124 bp repetitive sequences was observed. Genomic DNA of the parasite was used as a positive control, which also gave an amplification of the 124 bp fragment. DNA isolated from non-infected snails was used as a negative control and no amplification of this sequence was observed. This technique is highly specific and sensitive and possesses fairly good prospects of its utility as an epidemiological tool for ascertaining the infectivity status in ubiquitous snail populations.

  3. Commercial watercress as an emerging source of fascioliasis in Northern France in 2002: results from an outbreak investigation.

    PubMed

    Mailles, A; Capek, I; Ajana, F; Schepens, C; Ilef, D; Vaillant, V

    2006-10-01

    In April 2002, five cases of fascioliasis were diagnosed in Tourcoing. A case-finding and a case-control study were carried out to identify the source of the outbreak and take appropriate control measures. Eighteen cases were identified through the medical laboratories carrying out serology for fascioliasis. Fourteen cases and 23 controls, identified by the physicians of the cases, were interviewed on symptoms of the disease and their consumption of uncooked plants. Cases were more likely than controls to have eaten commercialized raw watercress (OR 86.7, P < 0.001) and 13 (93%) of the cases reported its consumption. A single producer common to all cases was identified. The inspection of his watercress beds showed a lack of protection against Lymnaea truncatula. This outbreak of fascioliasis due to commercialized watercress indicates that actual sanitary regulations do not allow for the efficient prevention of infestation of watercress production in France.

  4. Toxic effects of crotocaudin extracted from the medicinal plant Croton tiglium.

    PubMed

    Yadav, Ram P; Singh, Ajay

    2010-01-01

    The compound crotocaudin extracted from the stem bark of the medicinal plant Croton tiglium Linn. was administered for 24 h or 96 h to the freshwater vector snail Lymnaea (Radix) acuminata Lamarck in order to test its toxicity. L. acuminata is the intermediate host of Fasciola hepatica and Fasciola gigantica which cause immense harm to man and his domestic animals. It was observed that the molluscicidal activity of crotocaudin against L. acuminata is time- as well as dose-dependent. There was a significant negative correlation among LC50 values and exposure periods, i.e. increasing the exposure time, the LC50 value of crotocaudin decreased from 5.37 microM (24 h) > 2.08 microM (48 h) > 1.36 microM (72 h) to 1.01 microM (96 h), respectively, against L. acuminata. The toxicological experiments to proof for environmental toxicity, if any, have also been carried out on the non-target freshwater fish Channa punctatus (Bloch) [Channidae (Ophicephalidae)], which shares the habitat with L. acuminata. The sublethal doses of crotocaudin (40% and 80% of LC50) administered over 24 h caused significant changes in the carbohydrate and nitrogenous metabolisms in nervous, hepatopancreas, and ovotestis tissues of Lymnaea acuminata. Channa punctatus was also exposed to sublethal doses of crotocaudin (40% and 80% of 24-h LC50 of L. acuminata) for 96 h which showed significant alterations in the metabolism in muscle, liver, and gonad tissues. After withdrawal of crotocaudin the snail tissues recovered in part after 7 days and the fish tissues completely.

  5. Interactions among invaders: community and ecosystem effects of multiple invasive species in an experimental aquatic system.

    PubMed

    Johnson, Pieter T J; Olden, Julian D; Solomon, Christopher T; Vander Zanden, M Jake

    2009-02-01

    With ecosystems increasingly supporting multiple invasive species, interactions among invaders could magnify or ameliorate the undesired consequences for native communities and ecosystems. We evaluated the individual and combined effects of rusty crayfish (Orconectes rusticus) and Chinese mystery snails [Bellamya (=Cipangopaludina) chinensis] on native snail communities (Physa, Helisoma and Lymnaea sp.) and ecosystem attributes (algal chlorophyll a and nutrient concentrations). Both invaders are widespread in the USA and commonly co-occur within northern temperate lakes, underscoring the importance of understanding their singular and joint effects. An outdoor mesocosm experiment revealed that while the two invaders had only weakly negative effects upon one another, both negatively affected the abundance and biomass of native snails, and their combined presence drove one native species to extinction and reduced a second by >95%. Owing to its larger size and thicker shell, adult Bellamya were protected from crayfish attack relative to native species (especially Physa and Lymnaea), suggesting the co-occurrence of these invaders in nature could have elevated consequences for native communities. The per capita impacts of Orconectes (a snail predator) on native snails were substantially greater than those of Bellamya (a snail competitor). Crayfish predation also had a cascading effect by reducing native snail biomass, leading to increased periphyton growth. Bellamya, in contrast, reduced periphyton biomass, likely causing a reduction in growth by native lymnaeid snails. Bellamya also increased water column N:P ratio, possibly because of a low P excretion rate relative to native snail species. Together, these findings highlight the importance of understanding interactions among invasive species, which can have significant community- and ecosystem-level effects.

  6. Dose-dependent effects of the clinical anesthetic isoflurane on Octopus vulgaris: a contribution to cephalopod welfare.

    PubMed

    Polese, Gianluca; Winlow, William; Di Cosmo, Anna

    2014-12-01

    Recent progress in animal welfare legislation relating to invertebrates has provoked interest in methods for the anesthesia of cephalopods, for which different approaches to anesthesia have been tried but in most cases without truly anesthetizing the animals. For example, several workers have used muscle relaxants or hypothermia as forms of "anesthesia." Several inhalational anesthetics are known to act in a dose-dependent manner on the great pond snail Lymnaea stagnalis, a pulmonate mollusk. Here we report, for the first time, on the effects of clinical doses of the well-known inhalational clinical anesthetic isoflurane on the behavioral responses of the common octopus Octopus vulgaris. In each experiment, isoflurane was equilibrated into a well-aerated seawater bath containing a single adult O. vulgaris. Using a web camera, we recorded each animal's response to touch stimuli eliciting withdrawal of the arms and siphon and observed changes in the respiratory rate and the chromatophore pattern over time (before, during, and after application of the anesthetic). We found that different animals of the same size responded with similar behavioral changes as the isoflurane concentration was gradually increased. After gradual application of 2% isoflurane for a maximum of 5 min (at which time all the responses indicated deep anesthesia), the animals recovered within 45-60 min in fresh aerated seawater. Based on previous findings in gastropods, we believe that the process of anesthesia induced by isoflurane is similar to that previously observed in Lymnaea. In this study we showed that isoflurane is a good, reversible anesthetic for O. vulgaris, and we developed a method for its use.

  7. Graded hypoxia acts through a network of distributed peripheral oxygen chemoreceptors to produce changes in respiratory behaviour and plasticity.

    PubMed

    Janes, Tara A; Xu, Fenglian; Syed, Naweed I

    2015-07-01

    Respiratory behaviour relies critically upon sensory feedback from peripheral oxygen chemoreceptors. During environmental or systemic hypoxia, chemoreceptor input modulates respiratory central pattern generator activity to produce reflex-based increases in respiration and also shapes respiratory plasticity over longer timescales. The best-studied oxygen chemoreceptors are undoubtedly the mammalian carotid bodies; however, questions remain regarding this complex organ's role in shaping respiration in response to varying oxygen levels. Furthermore, many taxa possess distinct oxygen chemoreceptors located within the lungs, airways and cardiovasculature, but the functional advantage of multiple chemoreceptor sites is unclear. In this study, it is demonstrated that a distributed network of peripheral oxygen chemoreceptors exists in Lymnaea stagnalis and significantly modulates aerial respiration. Specifically, Lymnaea breath frequency and duration represent parameters that are shaped by interactions between hypoxic severity and its time-course. Using a combination of behaviour and electrophysiology approaches, the chemosensory pathways underlying hypoxia-induced changes in breath frequency/duration were explored. The current findings demonstrate that breath frequency is uniquely modulated by the known osphradial ganglion oxygen chemoreceptors during moderate hypoxia, while a newly discovered area of pneumostome oxygen chemoreception serves a similar function specifically during more severe hypoxia. Together, these findings suggest that multiple oxygen chemosensory sites, each with their own sensory and modulatory properties, act synergistically to form a functionally distributed network that dynamically shapes respiration in response to changing systemic or environmental oxygen levels. These distributed networks may represent an evolutionarily conserved strategy vis-à-vis respiratory adaptability and have significant implications for the understanding of fundamental

  8. High prevalence of cattle fascioliasis in coastal areas of Thua Thien Hue province, Vietnam

    PubMed Central

    NGUYEN, Nga Thi; LE, Thinh Cong; VO, Minh Duc Co; VAN CAO, Hoang; NGUYEN, Ly Thi; HO, Khanh Thi; NGUYEN, Quyet Ngoc; TRAN, Vui Quang; MATSUMOTO, Yasunobu

    2017-01-01

    In Vietnam, especially central Vietnam, patients with fascioliasis are increasingly being reported. Since the fascioliasis is zoonotic, survey on the cattle fascioliasis should be informative for the control of human fascioliasis. In this study, the prevalence of cattle fascioliasis as well as the density of the intermediate host snails, Lymnaea swinhoei and L. viridis, were studied in Thua Thien Hue (TTH) province during 2014–2015. A total of 572 cattle feces were examined from 27 communes in 9 districts. Fasciola eggs were detected in cattle from 24 communes with an average prevalence of 23.4% (134/ 572). The highest prevalence was detected in cattle in the coastal plain terrain (31.0%) followed by plain (25.5%), mountain (21.7%), and low hilly (16.2%) terrains. The highest proportion of heavy infection (>200 EPG) was observed in the coastal plain terrain (36.1%), followed by mountains (20.0%), low hills (13.0%), and plains (8.9%). Low number of heavy infection, as well as relatively low prevalence in low hills and plains were associated with the extensive use of anti-fluke treatments. High number of intermediate host snails in low hilly and plain terrains also indicate high risk of fascioliasis. In this study, the density of Lymnaea snails in the coastal plain terrain was found to be very high (17.3 snails/m2) compared to that in previous studies. This is the first report indicating the recent expansion of cattle fascioliasis in the coastal region in Vietnam. PMID:28458272

  9. The inclusion of downy mildews in a multi-locus-dataset and its reanalysis reveals a high degree of paraphyly in Phytophthora.

    PubMed

    Runge, Fabian; Telle, Sabine; Ploch, Sebastian; Savory, Elizabeth; Day, Brad; Sharma, Rahul; Thines, Marco

    2011-12-01

    Pathogens belonging to the Oomycota, a group of heterokont, fungal-like organisms, are amongst the most notorious pathogens in agriculture. In particular, the obligate biotrophic downy mildews and the hemibiotrophic members of the genus Phytophthora are responsible for a huge variety of destructive diseases, including sudden oak death caused by P. ramorum, potato late blight caused by P. infestans, cucurbit downy mildew caused by Pseudoperonospora cubensis, and grape downy mildew caused by Plasmopara viticola. About 800 species of downy mildews and roughly 100 species of Phytophthora are currently accepted, and recent studies have revealed that these groups are closely related. However, the degree to which Phytophthora is paraphyletic and where exactly the downy mildews insert into this genus in relation to other clades could not be inferred with certainty to date. Here we present a molecular phylogeny encompassing all clades of Phytophthora as represented in a multi-locus dataset and two representatives of the monophyletic downy mildews from divergent genera. Our results demonstrate that Phytophthora is at least six times paraphyletic with respect to the downy mildews. The downy mildew representatives are consistently nested within clade 4 (contains Phytophthora palmivora), which is placed sister to clade 1 (contains Phytophthora infestans). This finding would either necessitate placing all downy mildews and Phytopthora species in a single genus, either under the oldest generic name Peronospora or by conservation the later name Phytophthora, or the description of at least six new genera within Phytophthora. The complications of both options are discussed, and it is concluded that the latter is preferable, as it warrants fewer name changes and is more practical.

  10. Validation of a portable, waterproof blood pH analyser for elasmobranchs

    PubMed Central

    Bouyoucos, Ian A.; Shipley, Oliver; Rummer, Jodie L.; Mandelman, John W.; Brooks, Edward J.; Grubbs, R. Dean

    2017-01-01

    Abstract Quantifying changes in blood chemistry in elasmobranchs can provide insights into the physiological insults caused by anthropogenic stress, and can ultimately inform conservation and management strategies. Current methods for analysing elasmobranch blood chemistry in the field are often costly and logistically challenging. We compared blood pH values measured using a portable, waterproof pH meter (Hanna Instruments HI 99161) with blood pH values measured by an i-STAT system (CG4+ cartridges), which was previously validated for teleost and elasmobranch fishes, to gauge the accuracy of the pH meter in determining whole blood pH for the Cuban dogfish (Squalus cubensis) and lemon shark (Negaprion brevirostris). There was a significant linear relationship between values derived via the pH meter and the i-STAT for both species across a wide range of pH values and temperatures (Cuban dogfish: 6.8–7.1 pH 24–30°C; lemon sharks: 7.0–7.45 pH 25–31°C). The relative error in the pH meter's measurements was ~±2.7%. Using this device with appropriate correction factors and consideration of calibration temperatures can result in both a rapid and accurate assessment of whole blood pH, at least for the two elasmobranch species examined here. Additional species should be examined in the future across a wide range of temperatures to determine whether correction factors are universal. PMID:28616238

  11. Genome-wide identification of MAPK, MAPKK, and MAPKKK gene families and transcriptional profiling analysis during development and stress response in cucumber.

    PubMed

    Wang, Jie; Pan, Changtian; Wang, Yan; Ye, Lei; Wu, Jian; Chen, Lifei; Zou, Tao; Lu, Gang

    2015-05-15

    The mitogen-activated protein kinase (MAPK) cascade consists of three types of reversibly phosphorylated kinases, namely, MAPK, MAPK kinase (MAPKK/MEK), and MAPK kinase kinase (MAPKKK/MEKK), playing important roles in plant growth, development, and defense response. The MAPK cascade genes have been investigated in detail in model plants, including Arabidopsis, rice, and tomato, but poorly characterized in cucumber (Cucumis sativus L.), a major popular vegetable in Cucurbitaceae crops, which is highly susceptible to environmental stress and pathogen attack. A genome-wide analysis revealed the presence of at least 14 MAPKs, 6 MAPKKs, and 59 MAPKKKs in the cucumber genome. Phylogenetic analyses classified all the CsMAPK and CsMAPKK genes into four groups, whereas the CsMAPKKK genes were grouped into the MEKK, RAF, and ZIK subfamilies. The expansion of these three gene families was mainly contributed by segmental duplication events. Furthermore, the ratios of non-synonymous substitution rates (Ka) and synonymous substitution rates (Ks) implied that the duplicated gene pairs had experienced strong purifying selection. Real-time PCR analysis demonstrated that some MAPK, MAPKK and MAPKKK genes are preferentially expressed in specific organs or tissues. Moreover, the expression levels of most of these genes significantly changed under heat, cold, drought, and Pseudoperonospora cubensis treatments. Exposure to abscisic acid and jasmonic acid markedly affected the expression levels of these genes, thereby implying that they may play important roles in the plant hormone network. A comprehensive genome-wide analysis of gene structure, chromosomal distribution, and evolutionary relationship of MAPK cascade genes in cucumber are present here. Further expression analysis revealed that these genes were involved in important signaling pathways for biotic and abiotic stress responses in cucumber, as well as the response to plant hormones. Our first systematic description of the MAPK

  12. Thirty-seventh supplement to the American Ornithologists' Union checklist of North American birds

    USGS Publications Warehouse

    Monroe, Burt L.; Banks, Richard C.; Fitzpatrick, John W.; Howell, Thomas R.; Johnson, Ned K.; Ouellet, Henri; Remsen, J.V.; Storer, Robert W.

    1989-01-01

    This third supplement subsequent to the 6th edition (1983) of the A.O.U. "Check-list of North American Birds" consists of changes adopted by the Committee on Classification and Nomenclature as of 1 March 1989. The changes fall into nine categories: (1) six species are added to the main list (Pterodroma longirostris, Larus crassirostris, Streptopelia decaocto, Cocccyzus julieni, Chrysolampis mosquitus, Emberiza aureola) because of new distributional information; (2) five species (Ara cubensis, Chlorostilbon bracei, Empidonax occidentalis, Polioptila californica, Pipilo crissalis) are added to the main list because of the splitting of species already on the list; (3) one name (Anthus rubescens) is changed because of the splitting of a species from outside the Checklist area; (4) two names (Morus bassanus, Nyctanassa violacea) is removed from the main list to Appendix B because of re-evaluation of Northern Hemisphere records; (6) three species (Pterodrama rostrata, P. alba, P. solandri) are moved from Appendix A to Appendix B, and one (P. defilippiana) is added to Appendix B because of questionable sight records; (7)A.O.U. numbers are added to three species (Ciccaba virgata, Myiopagis viridicata, Molothrus bonariensis) on the basis on new distributional records or supporting data; (8) several corrections in spelling or citations are made; and (9) English names are changed for twelve species to accommodate worldwide usage of these names. No new distributional information is included except as indicated above (i.e. minor changes of distribution are not noted). These actions bring the number of species recognized as occurring in North America (main list) to 1,945.

  13. Novel techniques and insights into the deployment of pop-up satellite archival tags on a small-bodied deep-water chondrichthyan

    NASA Astrophysics Data System (ADS)

    Shipley, Oliver N.; Howey, Lucy A.; Tolentino, Emily R.; Jordan, Lance K. B.; Brooks, Edward J.

    2017-01-01

    Acquiring movement data for small-bodied, deep-water chondrichthyans is challenged by extreme effects of capture and handling stress, and post-release predation, however, it is urgently required to examine important fisheries interactions and assess the ecological role of these species within deep-water food webs. Here we suggest a novel release-cage mechanism to deploy pop-up satellite archival tags, as well as present vertical habitat data for a data-deficient, small-bodied, deep-water bycatch species, the Cuban dogfish (Squalus cubensis). Data were gathered from seven of eight High Rate X-Tags deployed on mature Cuban dogfish in the Exuma Sound, The Bahamas. Recovery periods appeared variable between individuals and are likely driven by capture-and-handling stress and tag burden. Application of the cross-correlation function to time-series depth and temperature data indicated three of the seven individuals suffered mortality through predation, which occurred during daytime, and suggests Cuban dogfish may constitute a proportion of deep-water apex predator diet in the Exuma Sound. Two animals were successfully released via a novel release-cage mechanism and displayed either no, or rapid (<15 mins) vertically stationary recovery periods and were not consumed by predators; data for these individuals were recorded for the entire deployment duration (14 days). Vertical habitat data suggests Cuban dogfish are diel-vertical migrators, similar to other deep-water taxa, and exhibit a relatively broad temperature and depth range, which may be driven by preference for specific bathymetric structures. These techniques provide an important first step into acquiring and presenting vertical habitat data for small-bodied, deep-water chondrichthyans, which can be directly applied to fisheries and ecosystem-based management approaches.

  14. Thirty-seventh supplement to the American Ornithologists' Union Check-list of North American birds

    USGS Publications Warehouse

    Monroe, Burt L.; Banks, Richard C.; Fitzpatrick, John W.; Howell, Thomas R.; Johnson, Ned K.; Ouellet, Henri; Remsen, J.V.; Storer, Robert W.

    1989-01-01

    This third supplement subsequent to the 6th edition (1983) of the A.O.U. "Check-list of North American Birds" consists of changes adopted by the Committee on Classification and Nomenclature as of 1 March 1989. The changes fall into nine categories: (1) six species are added to the main list (Pterodroma longirostris, Larus crassirostris, Streptopelia decaocto, Cocccyzus julieni, Chrysolampis mosquitus, Emberiza aureola) because of new distributional information; (2) five species (Ara cubensis, Chlorostilbon bracei, Empidonax occidentalis, Polioptila californica, Pipilo crissalis) are added to the main list because of the splitting of species already on the list; (3) one name (Anthus rubescens) is changed because of the splitting of a species from outside the Checklist area; (4) two names (Morus bassanus, Nyctanassa violacea) is removed from the main list to Appendix B because of re-evaluation of Northern Hemisphere records; (6) three species (Pterodrama rostrata, P. alba, P. solandri) are moved from Appendix A to Appendix B, and one (P. defilippiana) is added to Appendix B because of questionable sight records; (7)A.O.U. numbers are added to three species (Ciccaba virgata, Myiopagis viridicata, Molothrus bonariensis) on the basis on new distributional records or supporting data; (8) several corrections in spelling or citations are made; and (9) English names are changed for twelve species to accommodate worldwide usage of these names. No new distributional information is included except as indicated above (i.e. minor changes of distribution are not noted). These actions bring the number of species recognized as occurring in North America (main list) to 1,945.

  15. [An early warning method of cucumber downy mildew in solar greenhouse based on canopy temperature and humidity modeling].

    PubMed

    Wang, Hui; Li, Mei-lan; Xu, Jian-ping; Chen, Mei-xiang; Li, Wen-yong; Li, Ming

    2015-10-01

    The greenhouse environmental parameters can be used to establish greenhouse nirco-climate model, which can combine with disease model for early warning, with aim of ecological controlling diseases to reduce pesticide usage, and protecting greenhouse ecological environment to ensure the agricultural product quality safety. Greenhouse canopy leaf temperature and air relative humidity, models were established using energy balance and moisture balance principle inside the greenhouse. The leaf temperature model considered radiation heat transfer between the greenhouse crops, wall, soil and cover, plus the heat exchange caused by indoor net radiation and crop transpiration. Furthermore, the water dynamic balance in the greenhouse including leaf transpiration, soil evaporation, cover and leaf water vapor condensation, was considered to develop a relative humidity model. The primary infection and latent period warning models for cucumber downy mildew (Pseudoperonospora cubensis) were validated using the results of the leaf temperature and relative humidity model, and then the estimated disease occurrence date of cucumber downy mildew was compared with actual disease occurrence date of field observation. Finally, the results were verified by the measured temperature and humidity data of September and October, 2014. The results showed that the root mean square deviations (RMSDs) of the measured and estimated leaf temperature were 0.016 and 0.024 °C, and the RMSDs of the measured and estimated air relative humidity were 0.15% and 0.13%, respectively. Combining the result of estimated temperature and humidity models, a cucumber disease early warning system was established to forecast the date of disease occurrence, which met with the real date. Thus, this work could provide the micro-environment data for the early warning system of cucumber diseases in solar greenhouses.

  16. Failure of delayed nonsynaptic neuronal plasticity underlies age-associated long-term associative memory impairment

    PubMed Central

    2012-01-01

    Background Cognitive impairment associated with subtle changes in neuron and neuronal network function rather than widespread neuron death is a feature of the normal aging process in humans and animals. Despite its broad evolutionary conservation, the etiology of this aging process is not well understood. However, recent evidence suggests the existence of a link between oxidative stress in the form of progressive membrane lipid peroxidation, declining neuronal electrical excitability and functional decline of the normal aging brain. The current study applies a combination of behavioural and electrophysiological techniques and pharmacological interventions to explore this hypothesis in a gastropod model (Lymnaea stagnalis feeding system) that allows pinpointing the molecular and neurobiological foundations of age-associated long-term memory (LTM) failure at the level of individual identified neurons and synapses. Results Classical appetitive reward-conditioning induced robust LTM in mature animals in the first quartile of their lifespan but failed to do so in animals in the last quartile of their lifespan. LTM failure correlated with reduced electrical excitability of two identified serotonergic modulatory interneurons (CGCs) critical in chemosensory integration by the neural network controlling feeding behaviour. Moreover, while behavioural conditioning induced delayed-onset persistent depolarization of the CGCs known to underlie appetitive LTM formation in this model in the younger animals, it failed to do so in LTM-deficient senescent animals. Dietary supplementation of the lipophilic anti-oxidant α-tocopherol reversed the effect of age on CGCs electrophysiological characteristics but failed to restore appetitive LTM function. Treatment with the SSRI fluoxetine reversed both the neurophysiological and behavioural effects of age in senior animals. Conclusions The results identify the CGCs as cellular loci of age-associated appetitive learning and memory

  17. Conopressin affects excitability, firing, and action potential shape through stimulation of transient and persistent inward currents in mulluscan neurons.

    PubMed

    van Soest, P F; Kits, K S

    1998-04-01

    The molluscan vasopressin/oxytocin-related neuropeptide conopressin activates two persistent inward currents in neurons from the anterior lobe of the right cerebral ganglion of Lymnaea stagnalis that are involved in the control of male copulatory behavior. The low-voltage-activated (LVA) current is activated at a wide range of membrane potentials, its amplitude being only weakly voltage dependent. The high-voltage-activated (HVA) current is activated at potentials positive to -40 mV only and shows a steep voltage dependence. Occurrence of both currents varies from cell to cell, some expressing both and others only the HVA current. In most neurons that have the LVA current, a conopressin-independent persistent inward current (INSR) is found that resembles the HVA current in its voltage dependence. The functional importance of the LVA and HVA currents was studied under current-clamp conditions in isolated anterior lobe neurons. In cells exhibiting both current types, the effect of activation of the LVA current alone was investigated as follows: previously recorded LVA current profiles were injected into the neurons, and the effects were compared with responses induced by conopressin. Both treatments resulted in a strong depolarization and firing activity. No differences in firing frequency and burst duration were observed, indicating that activation of the LVA current is sufficient to evoke bursts. In cells exhibiting only the HVA current, the effect of conopressin on the response to a depolarizing stimulus was tested. Conopressin reversibly increased the number of action potentials generated by the stimulus, suggesting that the HVA current enhances excitability and counteracts accommodation. Conopressin enhanced action potential broadening during depolarizing stimuli in many neurons. Voltage-clamp experiments performed under ion-selective conditions revealed the presence of transient sodium and calcium currents. Using the action potential clamp technique, it was

  18. Ultrastructural localization of NADPH diaphorase and nitric oxide synthase in the neuropils of the snail CNS.

    PubMed

    Nacsa, Kálmán; Elekes, Károly; Serfőző, Zoltán

    2015-08-01

    Comparative studies on the nervous system revealed that nitric oxide (NO) retains its function through the evolution. In vertebrates NO can act in different ways: it is released solely or as a co-transmitter, released from presynaptic or postsynaptic site, spreads as a volumetric signal or targets synaptic proteins. In invertebrates, however, the possible sites of NO release have not yet been identified. Therefore, in the present study, the subcellular distribution of the NO synthase (NOS) was examined in the central nervous system (CNS) of two gastropod species, the terrestrial snail, Helix pomatia and the pond snail, Lymnaea stagnalis, which are model species in comparative neurobiology. For the visualization of NOS NADPH-diaphorase histochemistry and an immunohistochemical procedure using a universal anti-NOS antibody were applied. At light microscopic level both techniques labeled identical structures in sensory tracts ramifying in the neuropils of central ganglia and cell bodies of the Lymnaea and Helix CNS. At ultrastructural level NADPH-d reactive/NOS-immunoreactive materials were localized on the nuclear envelope and membrane segments of the rough and smooth endoplasmic reticulum, as well as the cell membrane and axolemma of positive perikarya. NADPH-d reactive and NOS-immunoreactive varicosities connected to neighboring neurons with both unspecialized and specialized synaptic contacts. In the varicosities, the majority of the NADPH-d reactive/NOS-immunoreactive membrane segments were detected in round and pleomorph agranular vesicles of small size (50-200 nm). However, only a small portion (16%) of the vesicles displayed the NADPH-d reactivity/NOS-immunoreactivity. No evidence for the postsynaptic location of NOS was found. Our results suggest that the localization of NADPH-diaphorase and NOS is identical in the snail nervous system. In contrast to vertebrates, however, NO seems to act exclusively in an anterograde way possibly released from membrane

  19. Bovine fasciolosis at increasing altitudes: Parasitological and malacological sampling on the slopes of Mount Elgon, Uganda

    PubMed Central

    2012-01-01

    Background To clarify the extent and putative transmission zone of bovine fasciolosis on the slopes of Mount Elgon, Uganda, conjoint parasitological and malacological surveys, inclusive of inspection of animals at slaughter, were undertaken at increasing altitudes. Results A total of 239 cattle were sampled across eight locations ranging in elevation from 1112-2072 m. Faecal material was examined for presence of Fasciola eggs and sera were tested by ELISA for antibodies against Fasciola antigens. Bolstering this, 38 cattle at slaughter from 2 abattoir sites at 1150 m and 1947 m were inspected; in addition, wild buffalo stool (n = 10) opportunistically picked within Mount Elgon National Park (MENP) at 3640 m was examined. By faecal egg detection, prevalence of Fasciola gigantica at low (<1500 m) and high (>1500 m) altitude sites was 43.7% (95% CI 35.4-52.2) and 1.1% (95% CI 0.0-6.0), respectively, while by ELISA was much higher, low altitude - 77.9% (95% CI 69.7-85.4) and high altitude - 64.5% (95% CI 51.3-76.3). The decline in prevalence with increasing altitude was corroborated by abattoir sampling. Thirty seven aquatic habitats, ranging from 1139-3937 m in altitude were inspected for freshwater snails, 12 of which were within MENP. At lower altitudes, Lymnaea (Radix) natalensis was common, and often abundant, but at higher altitudes became much rarer ceasing to be found above 1800 m. On the other hand, Lymnaea (Galba) truncatula was found only at altitudes above 3000 m and within MENP alone. The snail identifications were confirmed by DNA analysis of the ribosomal 18S gene. Conclusions Active infections of F. gigantica in cattle are common in lower altitude settings but appear to diminish with increasing elevation. This is likely due to a growing paucity of intermediate hosts, specifically populations of L. natalensis for which a natural boundary of 1800 m appeared. Although F. hepatica was not encountered, the presence of several

  20. Larval settlement and spat recovery rates of the oyster Crassostrea brasiliana (Lamarck, 1819) using different systems to induce metamorphosis.

    PubMed

    Silveira, R C; Silva, F C; Gomes, C H M; Ferreira, J F; Melo, C M R

    2011-05-01

    This study aimed at the assessment, in the laboratory, of the larval settlement and spat recovery rates of oysters of the species Crassostrea brasiliana using plastic collectors, epinephrine (C9H13NO3 C4H6O6) and shell powder in settlement tanks. Polypropylene was used attached to bamboo frames. The material was chosen due to its pliability--that favours the spat detachment. Two experiments were carried out; the first between February and April 2008, and the second between November and December 2008 at the Marine Mussel Laboratory of Santa Catarina Federal University (Laboratório de Moluscos Marinhos da Universidade Federal de Santa Catarina). In the first experiment, the scratched plastic collectors were tested consorting them with shell powder; on the second, the plastic collectors were tested consorted with shell powder, only shell powder and epinephrine as the metamorphosis stimulator. The quantification was carried out of the larvae settled in the plastic collectors, and of the recovery and integrity of the spats after their detachment. The first experiment has shown a recovery rate of 48.83% of the spats in comparison with the D larvae used. From this percentage, 4.9% settled in the plastic collectors and 43.93% in shell powder. The second experiment revealed 55.78% regarding the settled spats in comparison with the total of larvae used (using epinephrine), 78.62% in the treatment with the collector plus shell powder and 58.33% in the treatment only with shell powder. Thus, the use of the collector plus shell powder resulted in a greater spat recovery when compared to the other treatments.

  1. pT305-CaMKII stabilizes a learning-induced increase in AMPA receptors for ongoing memory consolidation after classical conditioning

    PubMed Central

    Kemenes, György

    2014-01-01

    The role of CaMKII in learning-induced activation and trafficking of AMPA receptors (AMPARs) is well established. However, the link between the phosphorylation state of CaMKII and the agonist-triggered proteasomal degradation of AMPARs during memory consolidation remains unknown. Here we describe a novel CaMKII-dependent mechanism by which a learning-induced increase in AMPAR levels is stabilized for consolidation of associative long-term memory. Six hours after classical conditioning the levels of both autophosphorylated pT305-CaMKII and GluA1 type AMPAR subunits are significantly elevated in the ganglia containing the learning circuits of the snail Lymnaea stagnalis. CaMKIINtide treatment significantly reduces the learning-induced elevation of both pT305-CaMKII and GluA1 levels and impairs associative long-term memory. Inhibition of proteasomal activity offsets the deleterious effects of CaMKIINtide on both GluA1 levels and long-term memory. These findings suggest that increased levels of pT305-CaMKII play a role in AMPAR dependent memory consolidation by reducing proteasomal degradation of GluA1 receptor subunits. PMID:24875483

  2. Silver bioaccumulation dynamics in a freshwater invertebrate after aqueous and dietary exposures to nanosized and ionic Ag

    USGS Publications Warehouse

    le Croteau, Marie-Noe; Misra, Superb K.; Luoma, Samuel N.; Valsami-Jones, Eugenia

    2011-01-01

    We compared silver (Ag) bioavailability and toxicity to a freshwater gastropod after exposure to ionic silver (Ag+) and to Ag nanoparticles (Ag NPs) capped with citrate or with humic acid. Silver form, exposure route, and capping agent influence Ag bioaccumulation dynamics in Lymnaea stagnalis. Snails efficiently accumulated Ag from all forms after either aqueous or dietary exposure. For both exposure routes, uptake rates were faster for Ag+ than for Ag NPs. Snails efficiently assimilated Ag from Ag NPs mixed with diatoms (assimilation efficiency (AE) ranged from 49 to 58%) and from diatoms pre-exposed to Ag+ (AE of 73%). In the diet, Ag NPs damaged digestion. Snails ate less and inefficiently processed the ingested food, which adversely impacted their growth. Loss rates of Ag were faster after waterborne exposure to Ag NPs than after exposure to dissolved Ag+. Once Ag was taken up from diet, whether from Ag+ or Ag NPs, Ag was lost extremely slowly. Large Ag body concentrations are thus expected in L. stagnalis after dietborne exposures, especially to citrate-capped Ag NPs. Ingestion of Ag associated with particulate materials appears as the most important vector of uptake. Nanosilver exposure from food might trigger important environmental risks.

  3. Survival and Growth of Freshwater Pulmonate and Nonpulmonate Snails in 28-Day Exposures to Copper, Ammonia, and Pentachlorophenol.

    PubMed

    Besser, John M; Dorman, Rebecca A; Hardesty, Douglas L; Ingersoll, Christopher G

    2016-02-01

    We performed toxicity tests with two species of pulmonate snails (Lymnaea stagnalis and Physa gyrina) and four taxa of nonpulmonate snails in the family Hydrobiidae (Pyrgulopsis robusta, Taylorconcha serpenticola, Fluminicola sp., and Fontigens aldrichi). Snails were maintained in static-renewal or recirculating culture systems with adults removed periodically to isolate cohorts of offspring for toxicity testing. This method successfully produced offspring for both species of pulmonate snails and for two hydrobiid species, P. robusta and Fluminicola sp. Toxicity tests were performed for 28 days with copper, ammonia, and pentachlorophenol in hard reconstituted water with endpoints of survival and growth. Tests were started with 1-week-old L. stagnalis, 2-week-old P. gyrina, 5- to 13-week-old P. robusta and Fluminicola sp., and older juveniles and adults of several hydrobiid species. For all three chemicals, chronic toxicity values for pulmonate snails were consistently greater than those for hydrobiid snails, and hydrobiids were among the most sensitive taxa in species sensitivity distributions for all three chemicals. These results suggest that the toxicant sensitivity of nonpulmonate snails in the family Hydrobiidae would not be adequately represented by results of toxicity testing with pulmonate snails.

  4. Bioaccumulation and toxicity of CuO nanoparticles by a freshwater invertebrate after waterborne and dietborne exposures

    USGS Publications Warehouse

    Croteau, Marie-Noele; Misra, Superb K.; Luoma, Samuel N.; Valsami-Jones, Eugenia

    2014-01-01

    The incidental ingestion of engineered nanoparticles (NPs) can be an important route of uptake for aquatic organisms. Yet, knowledge of dietary bioavailability and toxicity of NPs is scarce. Here we used isotopically modified copper oxide (65CuO) NPs to characterize the processes governing their bioaccumulation in a freshwater snail after waterborne and dietborne exposures. Lymnaea stagnalis efficiently accumulated 65Cu after aqueous and dietary exposures to 65CuO NPs. Cu assimilation efficiency and feeding rates averaged 83% and 0.61 g g–1 d–1 at low exposure concentrations (–1), and declined by nearly 50% above this concentration. We estimated that 80–90% of the bioaccumulated 65Cu concentration in L. stagnalis originated from the 65CuO NPs, suggesting that dissolution had a negligible influence on Cu uptake from the NPs under our experimental conditions. The physiological loss of 65Cu incorporated into tissues after exposures to 65CuO NPs was rapid over the first days of depuration and not detectable thereafter. As a result, large Cu body concentrations are expected in L. stagnalis after exposure to CuO NPs. To the degree that there is a link between bioaccumulation and toxicity, dietborne exposures to CuO NPs are likely to elicit adverse effects more readily than waterborne exposures.

  5. Molecular diversity of avian schistosomes in Danish freshwater snails.

    PubMed

    Christiansen, Anne Ø; Olsen, Annette; Buchmann, Kurt; Kania, Per W; Nejsum, Peter; Vennervald, Birgitte J

    2016-03-01

    Avian schistosomes are widespread parasites of snails and waterfowl and may cause cercarial dermatitis (swimmer's itch) in humans, a disease that is frequently reported in European countries. These parasites are known to occur in Denmark, but here, we applied a new approach using molecular tools to identify the parasites at species level. In order to do that, 499 pulmonate freshwater snails (Radix sp., Lymnaea stagnalis, Stagnicola sp. and Planorbarius corneus) were sampled from 12 lakes, ponds, and marshes in the greater Copenhagen area. Avian schistosome cercariae were identified by microscopy and subjected to molecular investigation by sequencing and phylogenetic analysis of the 5.8S and ITS2 ribosomal DNA for species identification. Additionally, snail hosts belonging to the genus Radix were identified by sequencing and phylogenetic analysis of partial ITS2 ribosomal DNA. Three out of 499 snails shed different species of Trichobilharzia cercariae: Trichobilharzia szidati was isolated from L. stagnalis, Trichobilharzia franki from Radix auricularia and Trichobilharzia regenti from Radix peregra. In the light of the public health risk represented by bird schistosomes, these findings are of concern and, particularly, the presence of the potentially neuro-pathogenic species, T. regenti, in Danish freshwaters calls for attention.

  6. Associations between trematode infections in cattle and freshwater snails in highland and lowland areas of Iringa Rural District, Tanzania.

    PubMed

    Nzalawahe, Jahashi; Kassuku, Ayub A; Stothard, J Russell; Coles, Gerald C; Eisler, Mark C

    2015-09-01

    The epidemiology of trematode infections in cattle was investigated within highland and lowland areas of Iringa Rural District, in southern Tanzania. Fecal samples were collected from 450 cattle in 15 villages at altitudes ranging from 696 to 1800 m above the sea level. Freshwater snails were collected from selected water bodies and screened for emergence of cercariae. The infection rates in cattle were Fasciola gigantica 28·2%, paramphistomes 62·8% and Schistosoma bovis 4·8%. Notably, prevalence of trematode infections in cattle was much higher in highland (altitude > 1500 m) as compared with lowland (altitude < 1500 m) areas and was statistically significant (P-value = 0·000) for F. gigantica and paramphistomes but not for S. bovis. The snails collected included Lymnaea natalensis, Bulinus africanus, Bulinus tropicus, Bulinus forskali, Biomphalaria pfeifferi, Melanoides tuberculata and Bellamya constricta with a greater proportion of highland (75%) than lowland (36%) water bodies harbouring snails. Altitude is a major factor shaping the epidemiology of F. gigantica and paramphistomes infections in cattle in Iringa Rural District with greater emphasis upon control needed in highland areas.

  7. Fascioliasis Control: In Vivo and In Vitro Phytotherapy of Vector Snail to Kill Fasciola Larva

    PubMed Central

    Sunita, Kumari; Singh, D. K.

    2011-01-01

    Snail is one of the important components of an aquatic ecosystem, it acts as intermediate host of Fasciola species. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. Life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria in the snail body. In vivo and in vitro toxicity of the plant products and their active component such as citral, ferulic acid, umbelliferone, azadirachtin, and allicin against larva of Fasciola in infected snail Lymnaea acuminata were tested. Mortality of larvae were observed at 2 h, 4 h, 6 h, and 8 h, of treatment. In in vivo treatment, azadirachtin caused highest mortality in redia and cercaria larva (8 h, LC50 0.11, and 0.05 mg/L) whereas in in vitro condition allicin was highly toxic against redia and cercaria (8 h, LC50 0.01, and 0.009 mg/L). Toxicity of citral was lowest against redia and cercaria larva. PMID:22132306

  8. In vitro PHYTOTHERAPY OF VECTOR SNAILS BY BINARY COMBINATIONS OF LARVICIDAL ACTIVE COMPONENTS IN EFFECTIVE CONTROL OF FASCIOLIASIS

    PubMed Central

    Sunita, Kumari; Kumar, Pradeep; Singh, Vinay Kumar; Singh, Dinesh Kumar

    2013-01-01

    SUMMARY A food-borne trematode infection fascioliasis is one among common public health problems worldwide. It caused a great economic loss for the human race. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. The life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria inside of the snail Lymnaea acuminata. In vitro toxicity of different binary combinations (1:1 ratio) of plant-derived larvicidal active components such as citral, ferulic acid, umbelliferone, azadirachtin and allicin against Fasciola redia and cercaria were tested. The mortality of larvae was observed at 2h, 4h, 6h and 8h of treatment. In in vitro condition azadirachtin + allicin (1:1 ratio) was highly toxic against redia and cercaria (8h LC50 0.006 and 0.005 mg/L). Toxicity of citral + ferulic acid was lowest against redia and cercaria larvae. PMID:24037283

  9. Laboratory assessment of the molluscicidal and cercaricidal activities of the Egyptian weed, Solanum nigrum L.

    PubMed

    Ahmed, A H; Ramzy, R M

    1997-12-01

    The molluscicidal properties of Solanum nigrum L. were tested against three Egyptian snail species (Biomphalaria alexandrina, Bulinus truncatus and Lymnaea natalensis), each an intermediate host of parasites causing human schistosomiasis or fascioliasis. The plant was collected in two regions within Egypt: Fayium and Giza. Snails were exposed for 24 and 48 h, to the dry powdered fruits and leaves or to crude water extracts of the powders, and mortality was recorded. The water extract of the leaves collected in Fayium (FLWE) had the highest molluscicidal activity, with median lethal concentrations (LC50) of 18.6 mg/litre for Bi. alexandrina, 14.5 mg/litre for Bu. truncatus and 17.7 mg/litre for L. natalensis. When Bi. alexandrina infected with Schistosoma mansoni were exposed to FLWE (20 or 25 mg/litre), they shed significantly fewer cercariae than unexposed snails (P < 0.02). The cercaricidal properties of FLWE were directly tested against S. haematobium, S. mansoni and Fasciola gigantica cercariae and a time-concentration relationship was observed; the concentrations needed to kill all cercariae (LC100) within 30 min of exposure were 30 mg/litre for both S. haematobium and S. mansoni and 40 mg/litre for F. gigantica.

  10. Photomediated Larvicidal Activity of Pheophorbide a against Cercaria Larvae of Fasciola gigantica

    PubMed Central

    Singh, Divya Jyoti; Singh, Vinay Kumar

    2017-01-01

    Fasciolosis is a parasitic disease caused by Fasciola gigantica. The freshwater snail Lymnaea acuminata is the intermediate host of F. gigantica which cause endemic fasciolosis in the northern part of India. To investigate larvicidal activity of pure and laboratory extracted pheophorbide a (Pa) against cercaria larvae of F. gigantica, data were analyzed in different spectra of visible light, sunlight, and laboratory conditions. Photostimulation of chlorophyll derivative pheophorbide a (Pa) caused time and concentration dependent larvicidal activity against cercaria larvae of F. gigantica. Larvicidal activity of pure Pa under 650 nm and 400–650 nm (8 h LC50 0.006 mg/10 mL) was more pronounced than extracted Pa under same irradiations (650 nm LC50 0.12 mg/10 mL, 400–650 nm LC50 0.14 mg/10 mL). Lowest toxicity of pure (8 h LC50 0.14 mg/10 mL) and extracted Pa (8 h LC50 1.25 mg/10 mL) was noted under 400 nm. Pa was found to be toxic in laboratory conditions also. The results presented in this paper indicate that pheophorbide a possess potential larvicidal activity against Fasciola gigantica larvae in different wavelengths of visible light, sunlight, and laboratory conditions. PMID:28127494

  11. Laboratory maintenance of the bacterial endosymbiont, Neorickettsia sp., through the life cycle of a digenean, Plagiorchis elegans.

    PubMed

    Greiman, Stephen E; Tkach, Maksym; Vaughan, Jefferson A; Tkach, Vasyl V

    2015-10-01

    The Digenea (Platyhelminthes: Trematoda) are a diverse and complex group of internal metazoan parasites. These parasites can serve as hosts to obligate intracellular bacteria belonging to the genus Neorickettsia (Family: Anaplasmataceae). Neorickettsiae persist within all stages of the fluke life cycle and thus are maintained through vertical transmission. However, the low prevalence of Neorickettsia in nature limits study of their transmission biology at different steps of digenean life cycles. To resolve this dilemma, we have developed for the first time a laboratory model allowing to maintain Neorickettsia sp. through the whole life cycle of a digenean, Plagiorchis elegans. The laboratory life cycle of P. elegans consists of a snail first intermediate host, Lymnaea stagnalis, an aquatic arthropod second intermediate host, Culex pipiens (mosquito larva), and a vertebrate definitive host, Mesocricetus auratus (Syrian hamster). This paper focuses on the development of the laboratory life cycle, as well as outlines its potential uses in studying the transmission biology of Neorickettsia and its evolutionary relationship within its digenean host.

  12. The numbers game: quantitative analysis of Neorickettsia sp. propagation through complex life cycle of its digenean host using real-time qPCR.

    PubMed

    Greiman, Stephen E; Tkach, Vasyl V

    2016-07-01

    Bacteria of the genus Neorickettsia are obligate intracellular endosymbionts of parasitic flukes (Digenea) and are passed through the entire complex life cycle of the parasite by vertical transmission. Several species of Neorickettsia are known to cause diseases in domestic animals, wildlife, and humans. Quantitative data on the transmission of the bacteria through the digenean life cycle is almost completely lacking. This study quantified for the first time the abundance of Neorickettsia within multiple stages of the life cycle of the digenean Plagiorchis elegans. Snails Lymnaea stagnalis collected from a pond in North Dakota were screened for the presence of digenean cercariae, which were subsequently tested for the presence of Neorickettsia. Three L. stagnalis were found shedding P. elegans cercariae infected with Neorickettsia. These snails were used to initiate three separate laboratory life cycles and obtain all life cycle stages for bacterial quantification. A quantitative real-time PCR assay targeting the GroEL gene was developed to enumerate Neorickettsia sp. within different stages of the digenean life cycle. The number of bacteria significantly increased throughout all stages, from eggs to adults. The two largest increases in number of bacteria occurred during the period from eggs to cercariae and from 6-day metacercariae to 48-h juvenile worms. These two periods seem to be the most important for Neorickettsia propagation through the complex digenean life cycle and maturation in the definitive host.

  13. Survival and growth of freshwater pulmonate and nonpulmonate snails in 28-day exposures to copper, ammonia, and pentachlorophenol

    USGS Publications Warehouse

    Besser, John M.; Dorman, Rebecca A.; Hardesty, Douglas K.; Ingersoll, Christopher G.

    2016-01-01

    We performed toxicity tests with two species of pulmonate snails (Lymnaea stagnalis and Physa gyrina) and four taxa of nonpulmonate snails in the family Hydrobiidae (Pyrgulopsis robusta,Taylorconcha serpenticola, Fluminicola sp., and Fontigens aldrichi). Snails were maintained in static-renewal or recirculating culture systems with adults removed periodically to isolate cohorts of offspring for toxicity testing. This method successfully produced offspring for both species of pulmonate snails and for two hydrobiid species, P. robusta and Fluminicola sp. Toxicity tests were performed for 28 days with copper, ammonia, and pentachlorophenol in hard reconstituted water with endpoints of survival and growth. Tests were started with 1-week-old L. stagnalis, 2-week-old P. gyrina, 5- to 13-week-old P. robusta and Fluminicola sp., and older juveniles and adults of several hydrobiid species. For all three chemicals, chronic toxicity values for pulmonate snails were consistently greater than those for hydrobiid snails, and hydrobiids were among the most sensitive taxa in species sensitivity distributions for all three chemicals. These results suggest that the toxicant sensitivity of nonpulmonate snails in the family Hydrobiidae would not be adequately represented by results of toxicity testing with pulmonate snails.

  14. Phylogenetic and individual variation in gastropod central pattern generators.

    PubMed

    Sakurai, Akira; Katz, Paul S

    2015-09-01

    Gastropod molluscs provide a unique opportunity to explore the neural basis of rhythmic behaviors because of the accessibility of their nervous systems and the number of species that have been examined. Detailed comparisons of the central pattern generators (CPGs) underlying rhythmic feeding and swimming behaviors highlight the presence and effects of variation in neural circuits both across and within species. The feeding motor pattern of the snail, Lymnaea, is stereotyped, whereas the feeding motor pattern in the sea hare, Aplysia, is variable. However, the Aplysia motor pattern is regularized with operant conditioning or by mimicking learning using the dynamic clamp to change properties of CPG neurons. Swimming evolved repeatedly in marine gastropods. Distinct neural mechanisms underlie dissimilar forms of swimming, with homologous neurons playing different roles. However, even similar swimming behaviors in different species can be produced by distinct neural mechanisms, resulting from different synaptic connectivity of homologous neurons. Within a species, there can be variation in the strength and even valence of synapses, which does not have functional relevance under normal conditions, but can cause some individuals to be more susceptible to lesion of the circuit. This inter- and intra-species variation provides novel insights into CPG function and plasticity.

  15. Modelling spatial distribution of snails transmitting parasitic worms with importance to human and animal health and analysis of distributional changes in relation to climate.

    PubMed

    Pedersen, Ulrik B; Midzi, Nicholas; Mduluza, Takafira; Soko, White; Stensgaard, Anna-Sofie; Vennervald, Birgitte J; Mukaratirwa, Samson; Kristensen, Thomas K

    2014-05-01

    The environment, the on-going global climate change and the ecology of animal species determine the localisation of habitats and the geographical distribution of the various species in nature. The aim of this study was to explore the effects of such changes on snail species not only of interest to naturalists but also of importance to human and animal health. The spatial distribution of freshwater snail intermediate hosts involved in the transmission of schistosomiasis, fascioliasis and paramphistomiasis (i.e. Bulinus globosus, Biomphalaria pfeifferi and Lymnaea natalensis) were modelled by the use of a maximum entropy algorithm (Maxent). Two snail observation datasets from Zimbabwe, from 1988 and 2012, were compared in terms of geospatial distribution and potential distributional change over this 24-year period investigated. Climate data, from the two years were identified and used in a species distribution modelling framework to produce maps of predicted suitable snail habitats. Having both climate- and snail observation data spaced 24 years in time represent a unique opportunity to evaluate biological response of snails to changes in climate variables. The study shows that snail habitat suitability is highly variable in Zimbabwe with foci mainly in the central Highveld but also in areas to the South and West. It is further demonstrated that the spatial distribution of suitable habitats changes with variation in the climatic conditions, and that this parallels that of the predicted climate change.

  16. Dietary uptake of Cu sorbed to hydrous iron oxide is linked to cellular toxicity and feeding inhibition in a benthic grazer

    USGS Publications Warehouse

    Cain, Daniel J.; Croteau, Marie-Noele; Fuller, Christopher C.; Ringwood, Amy H.

    2016-01-01

    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 104 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.

  17. Novel and nontraditional use of stable isotope tracers to study metal bioavailability from natural particles.

    PubMed

    Croteau, Marie-Noële; Cain, Daniel J; Fuller, Christopher C

    2013-04-02

    We devised a novel tracing approach that involves enriching test organisms with a stable metal isotope of low natural abundance prior to characterizing metal bioavailability from natural inorganic particles. In addition to circumventing uncertainties associated with labeling natural particles and distinguishing background metals, the proposed "reverse labeling" technique overcomes many drawbacks inherent to using radioisotope tracers. Specifically, we chronically exposed freshwater snails ( Lymnaea stagnalis ) to synthetic water spiked with Cu that was 99.4% (65)Cu to increase the relative abundance of (65)Cu in the snail's tissues from ~32% to >80%. The isotopically enriched snails were then exposed to benthic algae mixed with Cu-bearing Fe-Al particles collected from the Animas River (Colorado), an acid mine drainage impacted river. We used (63)Cu to trace Cu uptake from the natural particles and inferred their bioavailability from calculation of Cu assimilation into tissues. Cu assimilation from these particles was 44%, indicating that 44% of the particulate Cu was absorbed by the invertebrate. This demonstrates that inorganic particulate Cu can be bioavailable. The reverse labeling approach shows great potential in various scientific areas such as environmental contamination and nutrition for addressing questions involving uptake of an element that naturally has multiple isotopes.

  18. Assessing the Dietary Bioavailability of Metals Associated with Natural Particles: Extending the Use of the Reverse Labeling Approach to Zinc.

    PubMed

    Croteau, Marie-Noële; Cain, Daniel J; Fuller, Christopher C

    2017-03-07

    We extend the use of a novel tracing technique to quantify the bioavailability of zinc (Zn) associated with natural particles using snails enriched with a less common Zn stable isotope. Lymnaea stagnalis is a model species that has relatively fast Zn uptake rates from the dissolved phase, enabling their rapid enrichment in (67)Zn during the initial phase of labeling. Isotopically enriched snails were subsequently exposed to algae mixed with increasing amounts of metal-rich particles collected from two acid mine drainage impacted rivers. Zinc bioavailability from the natural particles was inferred from calculations of (66)Zn assimilation into the snail's soft tissues. Zinc assimilation efficiency (AE) varied from 28% for the Animas River particles to 45% for the Snake River particles, indicating that particle-bound, or sorbed Zn, was bioavailable from acid mine drainage wastes. The relative binding strength of Zn sorption to the natural particles was inversely related to Zn bioavailability; a finding that would not have been possible without using the reverse labeling approach. Differences in the chemical composition of the particles suggest that their geochemical properties may influence the extent of Zn bioavailability.

  19. Are Sick Individuals Weak Competitors? Competitive Ability of Snails Parasitized by a Gigantism-Inducing Trematode

    PubMed Central

    Seppälä, Otto; Karvonen, Anssi; Kuosa, Marja; Haataja, Maarit; Jokela, Jukka

    2013-01-01

    Parasitized individuals are often expected to be poor competitors because they are weakened by infections. Many trematode species, however, although extensively exploiting their mollusc hosts, also induce gigantism (increased host size) by diverting host resources towards growth instead of reproduction. In such systems, alternatively to reduced competitive ability due to negative effects of parasitism on host performance, larger size could allow more efficient resource acquisition and thus increase the relative competitive ability of host individuals. We addressed this hypothesis by testing the effect of a trematode parasite Diplostomum pseudospathaceum on the competitive ability of its snail host Lymnaea stagnalis. We experimentally examined the growth of snails kept in pairs in relation to their infection status and intensity of resource competition (i.e. food availability). We found that parasitized snails grew faster and their reproduction was reduced compared to unparasitized individuals indicating parasite-induced gigantism. However, growth of the snails was faster when competing with parasitized individuals compared to unparasitized snails indicating reduced competitive ability due to parasitism. The latter effect, however, was relatively weak suggesting that the effects of the parasite on snail physiology may partly override each other in determining competitive ability. PMID:24205383

  20. Mitochondrial Insult in a Parkinson's like symptoms model

    NASA Astrophysics Data System (ADS)

    Carrizales, Julio; Cantu, Manuel; Plas, Daniel; Daniel Plas Lab Team, Dr.

    2014-03-01

    Healthy cells require healthy mitochondria. If these organelles are damaged, many health consequences follow. For example, Parkinson's Disease (PD) is a major neurodegenerative disorder of unknown cause, but much evidence points to the mitochondrion as a key player in the onset of this disease. PD has been studied in animal models challenged with toxins that target the mitochondria. In our work, we have used the pesticide, Rotenone, a known inhibitor of protein Complex I in the mitochondrial electron transport chain. When this toxin is applied to the freshwater mollusk, Lymnaea stagnalis, or pond snail, severe motor deficits ensue. In this project, we are studying the direct effects of this toxin on mitochondrial structure and physiology. We expected that the morphology of the organelle may be altered. In addition, it is likely that the mitochondrial membrane potential necessary for normal function may decrease as the electron transport loses the ability to move protons from the matrix to the intermembrane space. we also are going to use Electrophysiology to compare and Identify the difference of the electrical signaling among healthy and unhealthy neurons. HHMI

  1. Biogeochemical controls of uranium bioavailability from the dissolved phase in natural freshwaters

    USGS Publications Warehouse

    Croteau, Marie-Noele; Fuller, Christopher C.; Cain, Daniel J.; Campbell, Kate M.; Aiken, George R.

    2016-01-01

    To gain insights into the risks associated with uranium (U) mining and processing, we investigated the biogeochemical controls of U bioavailability in the model freshwater speciesLymnaea stagnalis (Gastropoda). Bioavailability of dissolved U(VI) was characterized in controlled laboratory experiments over a range of water hardness, pH, and in the presence of complexing ligands in the form of dissolved natural organic matter (DOM). Results show that dissolved U is bioavailable under all the geochemical conditions tested. Uranium uptake rates follow first order kinetics over a range encompassing most environmental concentrations. Uranium uptake rates in L. stagnalis ultimately demonstrate saturation uptake kinetics when exposure concentrations exceed 100 nM, suggesting uptake via a finite number of carriers or ion channels. The lack of a relationship between U uptake rate constants and Ca uptake rates suggest that U does not exclusively use Ca membrane transporters. In general, U bioavailability decreases with increasing pH, increasing Ca and Mg concentrations, and when DOM is present. Competing ions did not affect U uptake rates. Speciation modeling that includes formation constants for U ternary complexes reveals that the aqueous concentration of dicarbonato U species (UO2(CO3)2–2) best predicts U bioavailability to L. stagnalis, challenging the free-ion activity model postulate.

  2. Trials with N-tritylmorpholine (Shell WL 8008) as a molluscicide in Southern Rhodesia

    PubMed Central

    Shiff, C. J.

    1966-01-01

    In the course of research into the effectiveness of new molluscicides for bilharziasis control, a recently developed compound, Shell WL 8008 (N-tritylmorpholine), has been tested in Southern Rhodesia, both in the laboratory and in the field. It is highly toxic to Bulinus (Physopsis) globosus, Biomphalaria pfeifferi and Lymnaea natalensis, all of which succumbed to the compound at a concentration of 1.0 ppm in a contact time of only 15 minutes. In experiments in reservoirs and natural watercourses, a concentrated aqueous suspension was sprayed on or just under the water surface, forming a white ”blanket” that sank at a rate depending on temperature, amount of vegetation, and so on. The period of contact with snails is sufficiently long for the molluscicide to kill them as it sinks; this characteristic is of great importance in the economic treatment of large stagnant water bodies or slow-moving streams. The compound is highly piscicidal, but has little effect on a wide range of microfauna. PMID:5297004

  3. Inhibition of nicotinic acetylcholine receptors, a novel facet in the pleiotropic activities of snake venom phospholipases A2.

    PubMed

    Vulfius, Catherine A; Kasheverov, Igor E; Starkov, Vladislav G; Osipov, Alexey V; Andreeva, Tatyana V; Filkin, Sergey Yu; Gorbacheva, Elena V; Astashev, Maxim E; Tsetlin, Victor I; Utkin, Yuri N

    2014-01-01

    Phospholipases A2 represent the most abundant family of snake venom proteins. They manifest an array of biological activities, which is constantly expanding. We have recently shown that a protein bitanarin, isolated from the venom of the puff adder Bitis arietans and possessing high phospholipolytic activity, interacts with different types of nicotinic acetylcholine receptors and with the acetylcholine-binding protein. To check if this property is characteristic to all venom phospholipases A2, we have studied the capability of these enzymes from other snakes to block the responses of Lymnaea stagnalis neurons to acetylcholine or cytisine and to inhibit α-bungarotoxin binding to nicotinic acetylcholine receptors and acetylcholine-binding proteins. Here we present the evidence that phospholipases A2 from venoms of vipers Vipera ursinii and V. nikolskii, cobra Naja kaouthia, and krait Bungarus fasciatus from different snake families suppress the acetylcholine- or cytisine-elicited currents in L. stagnalis neurons and compete with α-bungarotoxin for binding to muscle- and neuronal α7-types of nicotinic acetylcholine receptor, as well as to acetylcholine-binding proteins. As the phospholipase A2 content in venoms is quite high, under some conditions the activity found may contribute to the deleterious venom effects. The results obtained suggest that the ability to interact with nicotinic acetylcholine receptors may be a general property of snake venom phospholipases A2, which add a new target to the numerous activities of these enzymes.

  4. Long-term Changes in del 13C in DOC-based Benthic Food Webs in Arctic Lakes

    NASA Astrophysics Data System (ADS)

    Hershey, A. E.; O'Brien, W. J.; Fortino, K.; Keyse, M. D.; Binkley, E.; Lienesch, P. W.; McDonald, M. E.; Luecke, C.; Whalen, S.

    2005-05-01

    Arctic regions are rapidly warming, resulting in warmer summer lake temperatures and increased slumping of organic soils. In Lake NE-12, del 13C of primarily benthivorous lake trout has declined over eleven years. Two important lake trout prey, the caddisfly Grensia and the snail Lymnaea, also became more 13C-depleted. In Lake E-1, the deposit-feeding chironomid, Stictochironomus, also shifted toward lower del 13C, while filter-feeding Tanytarsini did not. Pelagic zooplankton did not show a trend toward 13C depletion overall, but were less consistent. Recent and concurrent studies have shown that DOC is an important resource for the benthic foodweb. Methanotrophy is part of the DOC-based foodweb. Our recent studies have shown that macrobenthos use some methanotroph production. Methane has very low del 13C, thus incorporation of a small amount of methane-based production has a large effect on del 13C. We suggest that climate-driven changes in the carbon pools available to microbes are resulting in increased importance of methanotrophs in macroinvertebrate diets, contributing to the observed long-term del 13C changes. Increased algal fractionation could also be important, but this mechanism has less support because zooplankton and filter-feeding chironomids did not show the same pattern, and previous studies have shown very limited benthic-pelagic coupling.

  5. Assessing the dietary bioavailability of metals associated with natural particles: Extending the use of the reverse labeling approach to zinc

    USGS Publications Warehouse

    Croteau, Marie-Noele; Cain, Daniel J.; Fuller, Christopher C.

    2017-01-01

    We extend the use of a novel tracing technique to quantify the bioavailability of zinc (Zn) associated with natural particles using snails enriched with a less common Zn stable isotope. Lymnaea stagnalis is a model species that has relatively fast Zn uptake rates from the dissolved phase, enabling their rapid enrichment in 67Zn during the initial phase of labeling. Isotopically enriched snails were subsequently exposed to algae mixed with increasing amounts of metal-rich particles collected from two acid mine drainage impacted rivers. Zinc bioavailability from the natural particles was inferred from calculations of 66Zn assimilation into the snail’s soft tissues. Zinc assimilation efficiency (AE) varied from 28% for the Animas River particles to 45% for the Snake River particles, indicating that particle-bound, or sorbed Zn, was bioavailable from acid mine drainage wastes. The relative binding strength of Zn sorption to the natural particles was inversely related to Zn bioavailability; a finding that would not have been possible without using the reverse labeling approach. Differences in the chemical composition of the particles suggest that their geochemical properties may influence the extent of Zn bioavailability.

  6. (Tri)butyltin biotic degradation rates and pathways in different compartments of a freshwater model ecosystem.

    PubMed

    Tessier, Emmanuel; Amouroux, David; Morin, Anne; Christian, Lehnhoff; Thybaud, Eric; Vindimian, Eric; Donard, Olivier F X

    2007-12-15

    Experiments were conducted in controlled temperate freshwater ecosystems (microcosms) to determine the persistence and biogeochemical dynamic of tributyltin (TBT) and its degradation products. TBT and its derivatives were monitored simultaneously for 23 days (552 h) in sediment-water systems, with or without macroorganisms (macrophytes: Elodea canadensis and gastropods: Lymnaea stagnalis). Biphasic TBT removal from the water column was significantly enhanced by the presence of biota. The persistence of TBT in biota was assessed by a kinetic approach of the different bioaccumulation pathways and associated metabolisms adopted by the snails and the macrophytes in response to the TBT contamination. Furthermore, sediment acted for the final sink for butyltins in both types of microcosms, with more than 70% of TBT and its metabolites recovered in this compartment after two weeks of exposure. Degradation pathways in sediments of both biotic and abiotic microcosms appeared to represent a key process in TBT cycle and were characterized by half-lives in the range of one month. Specific transformation and transfer pathways of TBT as reactional mechanisms are discussed and modelled assessing in detail the role of each compartment with regards to the fate of TBT in the model aquatic ecosystems.

  7. Novel and non-traditional use of stable isotope tracers to study metal bioavailability from natural particles

    USGS Publications Warehouse

    Croteau, Marie-Noële; Cain, Daniel J.; Fuller, Christopher C.

    2013-01-01

    We devised a novel tracing approach that involves enriching test organisms with a stable metal isotope of low natural abundance prior to characterizing metal bioavailability from natural inorganic particles. In addition to circumventing uncertainties associated with labeling natural particles and distinguishing background metals, the proposed "reverse labeling" technique overcomes many drawbacks inherent to using radioisotope tracers. Specifically, we chronically exposed freshwater snails (Lymnaea stagnalis) to synthetic water spiked with Cu that was 99.4% 65Cu to increase the relative abundance of 65Cu in the snail’s tissues from 32% to >80%. The isotopically enriched snails were then exposed to benthic algae mixed with Cu-bearing Fe–Al particles collected from the Animas River (Colorado), an acid mine drainage impacted river. We used 63Cu to trace Cu uptake from the natural particles and inferred their bioavailability from calculation of Cu assimilation into tissues. Cu assimilation from these particles was 44%, indicating that 44% of the particulate Cu was absorbed by the invertebrate. This demonstrates that inorganic particulate Cu can be bioavailable. The reverse labeling approach shows great potential in various scientific areas such as environmental contamination and nutrition for addressing questions involving uptake of an element that naturally has multiple isotopes.

  8. Effects of age, size, and mating history on sex role decision of a simultaneous hermaphrodite.

    PubMed

    Nakadera, Yumi; Swart, Elferra M; Maas, Jeroen P A; Montagne-Wajer, Kora; Ter Maat, Andries; Koene, Joris M

    2015-01-01

    Contrasting with separate-sexed animals, simultaneous hermaphrodites display unique reproductive strategies as they are male and female at the same time. Simultaneous hermaphrodites that copulate unilaterally, for instance, make a decision to mate as a male or female. Previous studies have demonstrated that sex role preference in hermaphrodites is flexible and is controlled by several, often confounding, factors. We examined the relationship between sex role decisions and 3 life-history traits (age, size, and mating history) in the great pond snail, Lymnaea stagnalis. Based on our field observations, which indicate that adult individuals show overlapping generations and large variation in body size during the breeding season, we performed a sex role choice experiment in the laboratory. We found that young and small snails mate as males first. Both age and size significantly affected sex role decision, with age having a stronger effect. Furthermore, we tested whether L. stagnalis becomes reluctant to inseminate a mate after being inseminated because it is known that after insemination, male investment substantially reduces. Contrary to expectations, our results indicate that the receipt of seminal fluid does not seem to reduce male motivation. In sum, sex role decisions in L. stagnalis are largely determined by age and size but not by having received seminal fluid. This mating pattern, however, does not fully support the size-advantage model because large or old individuals did not perform better as females in our experiment. These results imply a conflicting mating interest, rather than harmonious agreement, between age- and size-different hermaphrodites.

  9. Neuro-Endocrine Control of Reproduction in Hermaphroditic Freshwater Snails: Mechanisms and Evolution

    PubMed Central

    Koene, Joris M.

    2010-01-01

    Invertebrates are used extensively as model species to investigate neuro-endocrine processes regulating behaviors, and many of these processes may be extrapolated to vertebrates. However, when it comes to reproductive processes, many of these model species differ notably in their mode of reproduction. A point in case are simultaneously hermaphroditic molluscs. In this review I aim to achieve two things. On the one hand, I provide a comprehensive overview of the neuro-endocrine control of male and female reproductive processes in freshwater snails. Even though the focus will necessarily be on Lymnaea stagnalis, since this is the best-studied species in this respect, extensions to other species are made wherever possible. On the other hand, I will place these findings in the actual context of the whole animal, after all these are simultaneous hermaphrodites. By considering the hermaphroditic situation, I uncover a numbers of possible links between the regulation of the two reproductive systems that are present within this animal, and suggest a few possible mechanisms via which this animal can effectively switch between the two sexual roles in the flexible way that it does. Evidently, this opens up a number of new research questions and areas that explicitly integrate knowledge about behavioral decisions (e.g., mating, insemination, egg laying) and sexual selection processes (e.g., mate choice, sperm allocation) with the actual underlying neuronal and endocrine mechanisms required for these processes to act and function effectively. PMID:21088700

  10. About a snail, a toad, and rodents: animal models for adaptation research.

    PubMed

    Roubos, Eric W; Jenks, Bruce G; Xu, Lu; Kuribara, Miyuki; Scheenen, Wim J J M; Kozicz, Tamás

    2010-01-01

    Neural adaptation mechanisms have many similarities throughout the animal kingdom, enabling to study fundamentals of human adaptation in selected animal models with experimental approaches that are impossible to apply in man. This will be illustrated by reviewing research on three of such animal models, viz. (1) the egg-laying behavior of a snail, Lymnaea stagnalis: how one neuron type controls behavior, (2) adaptation to the ambient light condition by a toad, Xenopus laevis: how a neuroendocrine cell integrates complex external and neural inputs, and (3) stress, feeding, and depression in rodents: how a neuronal network co-ordinates different but related complex behaviors. Special attention is being paid to the actions of neurochemical messengers, such as neuropeptide Y, urocortin 1, and brain-derived neurotrophic factor. While awaiting new technological developments to study the living human brain at the cellular and molecular levels, continuing progress in the insight in the functioning of human adaptation mechanisms may be expected from neuroendocrine research using invertebrate and vertebrate animal models.

  11. The mechanism of extracellular stimulation of nerve cells on an electrolyte-oxide-semiconductor capacitor.

    PubMed

    Schoen, Ingmar; Fromherz, Peter

    2007-02-01

    Extracellular excitation of neurons is applied in studies of cultured networks and brain tissue, as well as in neuroprosthetics. We elucidate its mechanism in an electrophysiological approach by comparing voltage-clamp and current-clamp recordings of individual neurons on an insulated planar electrode. Noninvasive stimulation of neurons from pedal ganglia of Lymnaea stagnalis is achieved by defined voltage ramps applied to an electrolyte/HfO2/silicon capacitor. Effects on the smaller attached cell membrane and the larger free membrane are distinguished in a two-domain-stimulation model. Under current-clamp, we study the polarization that is induced for closed ion channels. Under voltage-clamp, we determine the capacitive gating of ion channels in the attached membrane by falling voltage ramps and for comparison also the gating of all channels by conventional variation of the intracellular voltage. Neuronal excitation is elicited under current-clamp by two mechanisms: Rising voltage ramps depolarize the free membrane such that an action potential is triggered. Falling voltage ramps depolarize the attached membrane such that local ion currents are activated that depolarize the free membrane and trigger an action potential. The electrophysiological analysis of extracellular stimulation in the simple model system is a basis for its systematic optimization in neuronal networks and brain tissue.

  12. The identification and characteristics of Echinoparyphium rubrum (Cort. 1914) new comb. (Trematoda, Echinostomatidae) based on experimental evidence of the life cycle

    USGS Publications Warehouse

    Kanev, I.; Sorensen, R.; Sterner, M.; Cole, R.; Fried, B.

    1998-01-01

    The life cycle of Echinoparyphium rubrum (Cort, 1914) comb. n. has been completed experimentally. All of the developmental stages egg, miracidium, sporocyst, mother and daughter rediae, cercaria, metacercaria, and adult were examined and described. The miracidia infected freshwater snails of the genus Physa , P. gyrina and P. occidentalis. Attempts to infect snails of the genera Lymnaea, L. auricularis, L. peregra, L. truncatula and Bulinus, B. truncatus failed. Cercariae infected various pulmonate and prosobranch freshwater snails, mussels, frogs, water turtles and planarians. The adults developed in the small intestine of birds and mammals. The identity and major characteristics of Echinoparyphium rubrum are discussed. Synonyms of E. rubrum are Cercaria rubra Cort, 1914; Cercaria biflexa Faust, 1917; Cercaria chisolenata Faust, 1918; Echinostoma callawayensis Barker et Noll, 1915; Echinostoma revolutum of Johnson (1920); Echinoparyphium elegans of Cannon (1938), of Bain and Trelfall (1977), of Mahoney and Trelfall (1977); and Echinoparyphium recurvatum of Jilek (1977), Harley (1972), Sankurathri and Holmes (1976). Comparisons are made between E. rubrum and its 43-collar-spined allies: E. flexum from North America, E. cinctum from Europe, E. dunni from Asia and E. elegans from Africa.

  13. Cloning and characterization of an ionotropic glutamate receptor subunit expressed in the squid nervous system.

    PubMed

    Battaglia, A A; Nardi, G; Steinhardt, A; Novakovic, A; Gentile, S; Iaccarino Idelson, P; Gilly, W F; de Santis, A

    2003-06-01

    In this paper we describe the cloning of a putative ionotropic glutamate receptor subunit, SqGluR, and its distribution in the nervous system of the squid. A full-length cDNA was assembled from a cDNA library of the stellate ganglion/giant fibre lobe complex of Loligo opalescens. The deduced amino acid sequence of the mature SqGluR displayed 44-46% amino acid identity with mammalian GluR1-GluR4 and 53% with Lym-eGluR1 from Lymnaea stagnalis. In situ hybridizations in adult squid confirmed that the SqGluR mRNA is abundant in giant fibre lobe neurons, in large, presumptive motor neurons of the stellate ganglion proper and in the supraoesophageal and optic lobes of the central nervous system. In newborn squid, SqGluR mRNA expression was detected throughout the nervous system but not elsewhere. A synthetic peptide corresponding to the last 15 amino acids of the SqGluR C-terminus was used to generate polyclonal antibodies, which were used for immunoblot analysis to demonstrate widespread expression in the squid central and peripheral nervous systems. Injection of the synthetic peptide into the postsynaptic side of the giant synapse inhibited synaptic transmission.

  14. Novel interactive effects of darkness and retinoid signaling in the ability to form long-term memory following aversive operant conditioning.

    PubMed

    Rothwell, Cailin M; Simmons, Jason; Peters, Grace; Spencer, Gaynor E

    2014-10-01

    The vitamin A metabolite, retinoic acid, is important for memory formation and hippocampal synaptic plasticity in vertebrate species. In our studies in the mollusc Lymnaea stagnalis, we have shown that retinoic acid plays a role in memory formation following operant conditioning of the aerial respiratory behaviour. Inhibition of either retinaldehyde dehydrogenase (RALDH) or the retinoid receptors prevents long-term memory (LTM) formation, whereas synthetic retinoid receptor agonists promote memory formation by converting intermediate-term memory (ITM) into LTM. In this study, animals were exposed to constant darkness in order to test whether light-sensitive retinoic acid would promote memory formation. However, we found that exposure to constant darkness alone (in the absence of retinoic acid) enhanced memory formation. To determine whether the memory-promoting effects of darkness could override the memory-inhibiting effects of the retinoid signaling inhibitors, we exposed snails to RALDH inhibitors or a retinoid receptor antagonist in constant darkness. We found that darkness overcame the inhibitory effects of RALDH inhibition, but did not overcome the inhibitory effects of the retinoid receptor antagonist. We also tested whether constant darkness and training affected the mRNA levels of the retinoid metabolic enzymes RALDH and Cyp26, or the mRNA levels of the retinoid receptors, but found no significant effect. Overall, these data demonstrate an interaction between environmental light conditions and the retinoid signaling pathway, which influence long-term memory formation in a mollusc. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Structural and Population Polymorphism of RT-Like Sequences in Avian Schistosomes Trichobilharzia szidati (Platyhelminthes: Digenea: Schistosomatidae)

    PubMed Central

    Semyenova, S. K.; Chrisanfova, G. G.; Guliaev, A. S.; Yesakova, A. P.; Ryskov, A. P.

    2015-01-01

    Recently we developed the genus-specific markers of the avian schistosomes of the genus Trichobilharzia, the causative agents of human cercarial dermatitis. The 7 novel genome sequences of T. franki, T. regenti, and T. szidati revealed similarity with genome repeat region of African schistosome Schistosoma mansoni. In the present work we analyzed the 37 new T. szidati sequences to study intragenome variability and host specificity for the parasite from three localities of East Europe. DNAs were isolated from cercariae or single sporocysts obtained from 6 lymnaeid snails Lymnaea stagnalis and L. palustris from Belarus and Russia. All sequences formed three diverged groups, one of which consists of the sequences with multiple deletions; other groups involved two paralogous copies with stop codons and frameshift mutations. Strong association between geographical distribution and snail host specificity cannot be established. All studied sequences have homology with the reverse transcriptase domain (RT) of Penelope-like elements (PLE) of S. mansoni and S. japonicum and new members of RT family were identified. We proposed that three diverged groups RT sequences of T. szidati are results of duplication or transposition of PLE during parasite evolution. Implications of the retroelement dynamics in the life history of avian schistosomes are discussed. PMID:26114104

  16. Photomediated Larvicidal Activity of Pheophorbide a against Cercaria Larvae of Fasciola gigantica.

    PubMed

    Singh, Divya Jyoti; Singh, Vinay Kumar; Singh, D K

    2017-01-01

    Fasciolosis is a parasitic disease caused by Fasciola gigantica. The freshwater snail Lymnaea acuminata is the intermediate host of F. gigantica which cause endemic fasciolosis in the northern part of India. To investigate larvicidal activity of pure and laboratory extracted pheophorbide a (Pa) against cercaria larvae of F. gigantica, data were analyzed in different spectra of visible light, sunlight, and laboratory conditions. Photostimulation of chlorophyll derivative pheophorbide a (Pa) caused time and concentration dependent larvicidal activity against cercaria larvae of F. gigantica. Larvicidal activity of pure Pa under 650 nm and 400-650 nm (8 h LC50 0.006 mg/10 mL) was more pronounced than extracted Pa under same irradiations (650 nm LC50 0.12 mg/10 mL, 400-650 nm LC50 0.14 mg/10 mL). Lowest toxicity of pure (8 h LC50 0.14 mg/10 mL) and extracted Pa (8 h LC50 1.25 mg/10 mL) was noted under 400 nm. Pa was found to be toxic in laboratory conditions also. The results presented in this paper indicate that pheophorbide a possess potential larvicidal activity against Fasciola gigantica larvae in different wavelengths of visible light, sunlight, and laboratory conditions.

  17. The life-cycle of Echinostoma friedi n. sp. (Trematoda: Echinostomatidae) in Spain and a discussion on the relationships within the 'revolutum' group based on cercarial chaetotaxy.

    PubMed

    Toledo, R; Muñoz-Antolí, C; Esteban, J G

    2000-03-01

    The morphology of the different stages and life-cycle of Echinostomna friedi n. sp. are described and figured. The freshwater snail Lymnaea peregra (Gastropoda: Lymnaeidae) serves as the natural and experimental first intermediate host and L. corvus and Gyraulus chinensis (Gastropoda: Planorbidae) as experimental first intermediate hosts. These, and Physella acuta (Gastropoda: Physidae), also serve as second intermediate hosts. Adult worms, possessing 37 collar spines, were obtained from naturally infected Rattus norvegicus and experimentally from albino rats, golden hamsters and chickens. Mice were not suitable experimental definitive hosts. E. friedi differs from the most closely related species in the 'revolutum' group mainly in terms of several morphological and biological features of the life-cycle stages and in its cercarial chaetotaxy. The chaetotaxy patterns of the species of the 'revolutum' group are analyzed and the results show that a taxonomic comparison of these species may be carried out on the basis of the number of sensilla in the clusters CIII VI, CIII V2 (or CIII V1 + CIII V2), CIV DL and UVb. These clusters appear adequate to establish taxonomic relationships between different species within the 'revolutum' group.

  18. The effects of the psychiatric drug carbamazepine on freshwater invertebrate communities and ecosystem dynamics.

    PubMed

    Jarvis, Amanda L; Bernot, Melody J; Bernot, Randall J

    2014-10-15

    Freshwater ecosystems are persistently exposed to pharmaceutical pollutants, including carbamazepine. Despite the ubiquity and recalcitrance of carbamazepine, the effects of this pharmaceutical on freshwater ecosystems and communities are unclear. To better understand how carbamazepine influences the invertebrate community and ecosystem dynamics in freshwaters, we conducted a mesocosm experiment utilizing environmentally relevant concentrations of carbamazepine (200 and 2000 ng/L). Mesocosms were populated with four gastropod taxa (Elimia, Physa, Lymnaea and Helisoma), zooplankton, filamentous algae and phytoplankton. After a 31 d experimental duration, structural equation modeling (SEM) was used to relate changes in the community structure and ecosystem dynamics to carbamazepine exposure. Invertebrate diversity increased in the presence of carbamazepine. Additionally, carbamazepine altered the biomass of Helisoma and Elimia, induced a decline in Daphnia pulex abundance and shifted the zooplankton community toward copepod dominance. Lastly, carbamazepine decreased the decomposition of organic matter and indirectly altered primary production and dissolved nutrient concentrations. Changes in the invertebrate community occurred through both direct (i.e., exposure to carbamazepine) and indirect pathways (i.e., changes in food resource availability). These data indicate that carbamazepine may alter freshwater community structure and ecosystem dynamics and could have profound effects on natural systems.

  19. Stimulus-dependent translocation of egg-laying hormone encoding mRNA into the axonal compartment of the neuroendocrine caudodorsal cells.

    PubMed

    van Minnen, J; Bergman, J J

    2003-11-01

    To get insight into the stimulus-dependent translocation of mRNA encoding neuropeptides to the axonal compartment of neurons, we investigated this process in the egg-laying hormone producing caudodorsal cells of the mollusk Lymnaea stagnalis. The axonal compartment including the nerve terminals of these neurons harbors high amounts of mRNA encoding the egg-laying hormone precursor. We determined how a sensory stimulus, that results in egg-laying, affected the amount of egg-laying hormone encoding transcripts in the axon endings. Four hours after stimulation high amounts of transcripts were detected in the axonal compartment and maximum values were reached after 8 h. Transcript levels in the somata were affected in a similar fashion, although the increase was not as pronounced as in the axons. Next, we investigated the ultrastructural localization of egg-laying hormone encoding transcripts in axons and axon terminals by means of electron microscopic in situ hybridization and showed that transcripts were localized in the axoplasm. By means of conventional electron microscopy we showed that axon terminals of egg-laying hormone producing neurons contained large amounts of polyribosomes. Together, these data support the notion that egg-laying hormone encoding transcripts are translated in the axonal compartment.

  20. Effect of Male Accessory Gland Products on Egg Laying in Gastropod Molluscs

    PubMed Central

    van Iersel, Sander; Swart, Elferra M.; Nakadera, Yumi; van Straalen, Nico M.; Koene, Joris M.

    2014-01-01

    In internally fertilizing animals, seminal fluid is usually added to the spermatozoa, together forming the semen or ejaculate. Besides nourishing and activating sperm, the components in the seminal fluid can also influence female physiology to augment fertilization success of the sperm donor. While many studies have reported such effects in species with separate sexes, few studies have addressed this in simultaneously hermaphroditic animals. This video protocol presents a method to study effects of seminal fluid in gastropods, using a simultaneously hermaphroditic freshwater snail, the great pond snail Lymnaea stagnalis, as model organism. While the procedure is shown using complete prostate gland extracts, individual components (i.e., proteins, peptides, and other compounds) of the seminal fluid can be tested in the same way. Effects of the receipt of ejaculate components on egg laying can be quantified in terms of frequency of egg laying and more subtle estimates of female reproductive performance such as egg numbers within each egg masses. Results show that seminal fluid proteins affect female reproductive output in this simultaneous hermaphrodite, highlighting their importance for sexual selection. PMID:24998794

  1. In Vitro Studies of Neuronal Networks and Synaptic Plasticity in Invertebrates and in Mammals Using Multielectrode Arrays

    PubMed Central

    Tessadori, Jacopo; Ghirardi, Mirella

    2015-01-01

    Brain functions are strictly dependent on neural connections formed during development and modified during life. The cellular and molecular mechanisms underlying synaptogenesis and plastic changes involved in learning and memory have been analyzed in detail in simple animals such as invertebrates and in circuits of mammalian brains mainly by intracellular recordings of neuronal activity. In the last decades, the evolution of techniques such as microelectrode arrays (MEAs) that allow simultaneous, long-lasting, noninvasive, extracellular recordings from a large number of neurons has proven very useful to study long-term processes in neuronal networks in vivo and in vitro. In this work, we start off by briefly reviewing the microelectrode array technology and the optimization of the coupling between neurons and microtransducers to detect subthreshold synaptic signals. Then, we report MEA studies of circuit formation and activity in invertebrate models such as Lymnaea, Aplysia, and Helix. In the following sections, we analyze plasticity and connectivity in cultures of mammalian dissociated neurons, focusing on spontaneous activity and electrical stimulation. We conclude by discussing plasticity in closed-loop experiments. PMID:25866681

  2. Structural mechanisms for α-conotoxin activity at the human α3β4 nicotinic acetylcholine receptor.

    PubMed

    Abraham, Nikita; Healy, Michael; Ragnarsson, Lotten; Brust, Andreas; Alewood, Paul F; Lewis, Richard J

    2017-03-31

    Nicotinic acetylcholine receptors (nAChR) are therapeutic targets for a range of human diseases. α-Conotoxins are naturally occurring peptide antagonists of nAChRs that have been used as pharmacological probes and investigated as drug leads for nAChR related disorders. However, α-conotoxin interactions have been mostly characterised at the α7 and α3β2 nAChRs, with interactions at other subtypes poorly understood. This study provides novel structural insights into the molecular basis for α-conotoxin activity at α3β4 nAChR, a therapeutic target where subtype specific antagonists have potential to treat nicotine addiction and lung cancer. A co-crystal structure of α-conotoxin LsIA with Lymnaea stagnalis acetylcholine binding protein guided the design and functional characterisations of LsIA analogues that identified the minimum pharmacophore regulating α3β4 antagonism. Interactions of the LsIA R10F with β4 K57 and the conserved -NN- α-conotoxin motif with β4 I77 and I109 conferred α3β4 activity to the otherwise inactive LsIA. Using these structural insights, we designed LsIA analogues with α3β4 activity. This new understanding of the structural basis of protein-protein interactions between α-conotoxins and α3β4 may help rationally guide the development of α3β4 selective antagonists with therapeutic potential.

  3. Unraveling the complexities of circadian and sleep interactions with memory formation through invertebrate research

    PubMed Central

    Michel, Maximilian; Lyons, Lisa C.

    2014-01-01

    Across phylogeny, the endogenous biological clock has been recognized as providing adaptive advantages to organisms through coordination of physiological and behavioral processes. Recent research has emphasized the role of circadian modulation of memory in generating peaks and troughs in cognitive performance. The circadian clock along with homeostatic processes also regulates sleep, which itself impacts the formation and consolidation of memory. Thus, the circadian clock, sleep and memory form a triad with ongoing dynamic interactions. With technological advances and the development of a global 24/7 society, understanding the mechanisms underlying these connections becomes pivotal for development of therapeutic treatments for memory disorders and to address issues in cognitive performance arising from non-traditional work schedules. Invertebrate models, such as Drosophila melanogaster and the mollusks Aplysia and Lymnaea, have proven invaluable tools for identification of highly conserved molecular processes in memory. Recent research from invertebrate systems has outlined the influence of sleep and the circadian clock upon synaptic plasticity. In this review, we discuss the effects of the circadian clock and sleep on memory formation in invertebrates drawing attention to the potential of in vivo and in vitro approaches that harness the power of simple invertebrate systems to correlate individual cellular processes with complex behaviors. In conclusion, this review highlights how studies in invertebrates with relatively simple nervous systems can provide mechanistic insights into corresponding behaviors in higher organisms and can be used to outline possible therapeutic options to guide further targeted inquiry. PMID:25136297

  4. Laboratory maintenance of the bacterial endosymbiont, Neorickettsia sp., through the life cycle of a digenean, Plagiorchis elegans

    PubMed Central

    Greiman, Stephen E.; Tkach, Maksym; Vaughan, Jefferson A.; Tkach, Vasyl V.

    2016-01-01

    The Digenea (Platyhelminthes: Trematoda) are a diverse and complex group of internal metazoan parasites. These parasites can serve as hosts to obligate intracellular bacteria belonging to the genus Neorickettsia (Family: Anaplasmataceae). Neorickettsiae persist within all stages of the fluke life cycle and thus are maintained through vertical transmission. However, the low prevalence of Neorickettsia in nature limits study of their transmission biology at different steps of digenean life cycles. To resolve this dilemma, we have developed for the first time a laboratory model allowing to maintain Neorickettsia sp. through the whole life cycle of a digenean, Plagiorchis elegans. The laboratory life cycle of P. elegans consists of a snail first intermediate host, Lymnaea stagnalis, an aquatic arthropod second intermediate host, Culex pipiens (mosquito larva), and a vertebrate definitive host, Mesocricetus auratus (Syrian hamster). This paper focuses on the development of the laboratory life cycle, as well as outlines its potential uses in studying the transmission biology of Neorickettsia and its evolutionary relationship within its digenean host. PMID:26160679

  5. Dietary Uptake of Cu Sorbed to Hydrous Iron Oxide is Linked to Cellular Toxicity and Feeding Inhibition in a Benthic Grazer.

    PubMed

    Cain, Daniel J; Croteau, Marie-Noële; Fuller, Christopher C; Ringwood, Amy H

    2016-02-02

    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.

  6. Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon

    USGS Publications Warehouse

    Lewis, Ariel S.; Huntington, Thomas G.; Marvin-DiPasquale, Mark C.; Amirbahman, Aria

    2016-01-01

    Wetlands are hotspots for production of toxic methylmercury (MeHg) that can bioaccumulate in the food web. The objective of this study was to determine whether the application of zero-valent iron (ZVI) or granular activated carbon (GAC) to wetland sediment could reduce MeHg production and bioavailability to benthic organisms. Field mesocosms were installed in a wetland fringing Hodgdon Pond (Maine, USA), and ZVI and GAC were applied. Pore-water MeHg concentrations were lower in treated compared with untreated mesocosms; however, sediment MeHg, as well as total Hg (THg), concentrations were not significantly different between treated and untreated mesocosms, suggesting that smaller pore-water MeHg concentrations in treated sediment were likely due to adsorption to ZVI and GAC, rather than inhibition of MeHg production. In laboratory experiments with intact vegetated sediment clumps, amendments did not significantly change sediment THg and MeHg concentrations; however, the mean pore-water MeHg and MeHg:THg ratios were lower in the amended sediment than the control. In the laboratory microcosms, snails (Lymnaea stagnalis) accumulated less MeHg in sediment treated with ZVI or GAC. The study results suggest that both GAC and ZVI have potential for reducing MeHg bioaccumulation in wetland sediment.

  7. Ligand-binding domain of an α7-nicotinic receptor chimera and its complex with agonist.

    PubMed

    Li, Shu-Xing; Huang, Sun; Bren, Nina; Noridomi, Kaori; Dellisanti, Cosma D; Sine, Steven M; Chen, Lin

    2011-09-11

    The α(7) acetylcholine receptor (AChR) mediates pre- and postsynaptic neurotransmission in the central nervous system and is a potential therapeutic target in neurodegenerative, neuropsychiatric and inflammatory disorders. We determined the crystal structure of the extracellular domain of a receptor chimera constructed from the human α(7) AChR and Lymnaea stagnalis acetylcholine binding protein (AChBP), which shares 64% sequence identity and 71% similarity with native α(7). We also determined the structure with bound epibatidine, a potent AChR agonist. Comparison of the structures revealed molecular rearrangements and interactions that mediate agonist recognition and early steps in signal transduction in α(7) AChRs. The structures further revealed a ring of negative charge within the central vestibule, poised to contribute to cation selectivity. Structure-guided mutational studies disclosed distinctive contributions to agonist recognition and signal transduction in α(7) AChRs. The structures provide a realistic template for structure-aided drug design and for defining structure-function relationships of α(7) AChRs.

  8. Bioaccumulation dynamics and modeling in an estuarine invertebrate following aqueous exposure to nanosized and dissolved silver.

    PubMed

    Khan, Farhan R; Misra, Superb K; García-Alonso, Javier; Smith, Brian D; Strekopytov, Stanislav; Rainbow, Philip S; Luoma, Samuel N; Valsami-Jones, Eugenia

    2012-07-17

    Predicting the environmental impact of engineered nanomaterials (ENMs) is increasingly important owing to the prevalence of emerging nanotechnologies. We derived waterborne uptake and efflux rate constants for the estuarine snail, Peringia ulvae, exposed to dissolved Ag (AgNO(3)) and silver nanoparticles (Ag NPs), using biodynamic modeling. Uptake rates demonstrated that dissolved Ag is twice as bioavailable as Ag in nanoparticle form. Biphasic loss dynamics revealed the faster elimination of Ag from Ag NPs at the start of depuration, but similar slow efflux rate constants. The integration of biodynamic parameters into our model accurately predicted Ag tissue burdens during chronic exposure with 85% of predicted values within a factor of 2 of observed values. Zeta potentials for the Ag NPs were lower in estuarine waters than in waters of less salinity; and uptake rates in P. ulvae were slower than reported for the freshwater snail Lymnaea stagnalis in similar experiments. This suggests aggregation of Ag NPs occurs in estuarine waters and reduces, but does not eliminate, bioavailability of Ag from the Ag NPs. Biodynamic modeling provides an effective methodology to determine bioavailable metal concentrations (originating from metal and metal-oxide nanoparticles) in the environment and may aid future ENM risk assessment.

  9. The neuronal control of cardiac functions in Molluscs☆

    PubMed Central

    Kodirov, Sodikdjon A.

    2017-01-01

    In this manuscript, I review the current and relevant classical studies on properties of the Mollusca heart and their central nervous system including ganglia, neurons, and nerves involved in cardiomodulation. Similar to mammalian brain hemispheres, these invertebrates possess symmetrical pairs of ganglia albeit visceral (only one) ganglion and the parietal ganglia (the right ganglion is bigger than the left one). Furthermore, there are two major regulatory drives into the compartments (pericard, auricle, and ventricle) and cardiomyocytes of the heart. These are the excitatory and inhibitory signals that originate from a few designated neurons and their putative neurotransmitters. Many of these neurons are well-identified, their specific locations within the corresponding ganglion are mapped, and some are termed as either heart excitatory (HE) or inhibitory (HI) cells. The remaining neurons are classified as cardio-regulatory, and their direct and indirect actions on the heart’s function have been documented. The cardiovascular anatomy of frequently used experimental animals, Achatina, Aplysia, Helix, and Lymnaea is relatively simple. However, as in humans, it possesses all major components including even trabeculae and atrio-ventricular valves. Since the myocardial cells are enzymatically dispersible, multiple voltage dependent cationic currents in isolated cardiomyocytes are described. The latter include at least the A-type K+, delayed rectifier K+, TTX-sensitive Na+, and L-type Ca2+ channels. PMID:21736949

  10. Regulation of seasonal reproduction in mollusks.

    PubMed

    Wayne, N L

    2001-08-01

    Understanding the physiological basis of environmental regulation of reproduction at the cellular level has been difficult or unfeasible in vertebrate species because of the highly complex and diffuse nature of vertebrate neuroendocrine systems. This is not the case with the simple nervous system of mollusks in which reproductive neuroendocrine cells are often readily identifiable in living tissue. Given that there are mollusks that are seasonal breeders, that the neuroendocrine cells controlling reproduction have been identified in several molluskan species, that these neurons are conducive to cell physiological analysis, and that basic features of cell biology have been highly conserved between mammals and mollusks, it seems that the mollusk would provide an excellent model system to investigate cell-physiological events that mediate effects of environmental signals on reproduction. The purpose of this review is to explore this idea in three species in which the topic of the neural basis of seasonal reproduction has been studied: the giant garden slug Limax maximus, the freshwater pond snail Lymnaea stagnalis, and the marine snail Aplysia californica.

  11. A biodynamic understanding of dietborne metal uptake by a freshwater invertebrate

    USGS Publications Warehouse

    Croteau, M.-N.; Luoma, S.N.

    2008-01-01

    Aquatic organisms accumulate metals from dissolved and particulate phases. Dietborne metal uptake likely prevails in nature, but the physiological processes governing metal bioaccumulation from diet are not fully understood. We characterize dietborne copper, cadmium, and nickel uptake by a freshwater gastropod (Lymnaea stagnalis) both in terms of biodynamics and membrane transport characteristics. We use enriched stable isotopes to trace newly accumulated metals from diet, determine food ingestion rate (IR) and estimate metal assimilation efficiency (AE). Upon 18-h exposure, dietborne metal influx was linear over a range encompassing most environmental concentrations. Dietary metal uptake rate constants (kuf) ranged from 0.104 to 0.162 g g -1 day-1, and appeared to be an expression of transmembrane transport characteristics. Although kuf values were 1000-times lower than uptake rate constants from solution, biodynamic modeling showed that diet is the major Cd, Cu, and Ni source in nature. AE varied slightly among metals and exposure concentrations (84-95%). Suppression of Cd and Cu influxes upon exposure to extreme concentrations coincided with a 10-fold decrease in food IR, suggesting that feeding inhibition could act as an end point for dietary metal toxicity in L. stagnalis.

  12. A biodynamic understanding of dietborne metal uptake by a freshwater invertebrate.

    PubMed

    Croteau, Marie-Noële; Luoma, Samuel N

    2008-03-01

    Aquatic organisms accumulate metals from dissolved and particulate phases. Dietborne metal uptake likely prevails in nature, but the physiological processes governing metal bioaccumulation from diet are not fully understood. We characterize dietborne copper, cadmium, and nickel uptake by a freshwater gastropod (Lymnaea stagnalis) both in terms of biodynamics and membrane transport characteristics. We use enriched stable isotopes to trace newly accumulated metals from diet, determine food ingestion rate (IR) and estimate metal assimilation efficiency (AE). Upon 18-h exposure, dietborne metal influx was linear over a range encompassing most environmental concentrations. Dietary metal uptake rate constants (k(uf)) ranged from 0.104 to 0.162 g g(-1) day(-1), and appeared to be an expression of transmembrane transport characteristics. Although k(uf) values were 1000-times lower than uptake rate constants from solution, biodynamic modeling showed that diet is the major Cd, Cu, and Ni source in nature. AE varied slightly among metals and exposure concentrations (84-95%). Suppression of Cd and Cu influxes upon exposure to extreme concentrations coincided with a 10-fold decrease in food IR, suggesting that feeding inhibition could act as an end point for dietary metal toxicity in L. stagnalis.

  13. Efficient expression of acetylcholine-binding protein from Aplysia californica in Bac-to-Bac system.

    PubMed

    Lin, Bo; Meng, Hailing; Bing, Hui; Zhangsun, Dongting; Luo, Sulan

    2014-01-01

    The Bac-to-Bac baculovirus expression system can efficiently produce recombinant proteins, but the system may have to be optimized to achieve high-level expression for different candidate proteins. We reported here the efficient expression of acetylcholine-binding proteins from sea hares Aplysia californica (Ac-AChBP) and a convenient method to monitor protein expression level in this expression system. Three key factors affecting expression of Ac-AChBP were optimized for maximizing the yield, which included the cell density, volume of the infecting baculovirus inoculums, and the culturing time of postinfection. We have found it to reach a high yield of ∼5 mg/L, which needs 55 h incubation after infection at the cell density of 2 × 10(6) cells/mL with an inoculum volume ratio of 1 : 100. The optimized expression system in this study was also applied for expressing another protein Ls-AChBP from Lymnaea stagnalis successfully. Therefore, this established method is helpful to produce high yields of AChBP proteins for X-ray crystallographic structural and functional studies.

  14. Diaphanous gene mutation affects spiral cleavage and chirality in snails

    PubMed Central

    Kuroda, Reiko; Fujikura, Kohei; Abe, Masanori; Hosoiri, Yuji; Asakawa, Shuichi; Shimizu, Miho; Umeda, Shin; Ichikawa, Futaba; Takahashi, Hiromi

    2016-01-01

    L-R (left and right) symmetry breaking during embryogenesis and the establishment of asymmetric body plan are key issues in developmental biology, but the onset including the handedness-determining gene locus still remains unknown. Using pure dextral (DD) and sinistral (dd) strains of the pond snail Lymnaea stagnalis as well as its F2 through to F10 backcrossed lines, the single handedness-determining-gene locus was mapped by genetic linkage analysis, BAC cloning and chromosome walking. We have identified the actin-related diaphanous gene Lsdia1 as the strongest candidate. Although the cDNA and derived amino acid sequences of the tandemly duplicated Lsdia1 and Lsdia2 genes are very similar, we could discriminate the two genes/proteins in our molecular biology experiments. The Lsdia1 gene of the sinistral strain carries a frameshift mutation that abrogates full-length LsDia1 protein expression. In the dextral strain, it is already translated prior to oviposition. Expression of Lsdia1 (only in the dextral strain) and Lsdia2 (in both chirality) decreases after the 1-cell stage, with no asymmetric localization throughout. The evolutionary relationships among body handedness, SD/SI (spiral deformation/spindle inclination) at the third cleavage, and expression of diaphanous proteins are discussed in comparison with three other pond snails (L. peregra, Physa acuta and Indoplanorbis exustus). PMID:27708420

  15. Avian schistosomes and human cercarial dermatitis in a wildlife refuge in Mazandaran Province, northern Iran.

    PubMed

    Gohardehi, S; Fakhar, M; Madjidaei, M

    2013-09-01

    Each year, hundreds of aquatic migratory birds migrate from northern hemisphere to the Mazandaran Province, northern Iran. Little information is available on prevalence and density of schistosomes in water birds in Iran and around the world. The objectives of this study were to determine definitive and intermediate hosts of avian schistosomes as well as to assess human cercarial dermatitis (HCD) in a wildlife refuge in Mazandaran Province. Of 1106 examined people, 589 (53.2%) had maculopapular rashes mainly on feet but also on hand. The majority of cases were adults and local residents. Of 260 ducks, 41 (15.8%) were found to be infected with Trichobilharzia spp. eggs or adult worms. Prevalence was highest in Anas clypeata and Anas platyrhynchos, 79% and 18.9%, respectively. A total of 1.2% snails, examined by both shedding and crushing methods, were infected with furcocercariae belonging to avian schistosomes. The most frequently infected snail was Lymnaea gedrosiana (5.9%). Our results showed that cercarial dermatitis and avian schistosomiasis is a common and yet neglected disease in this area. Anas clypeata played the most important role in exposing snails to miracidia in ponds and paddy fields. Moreover, because of the high prevalence in ducks and high prevalence of HCD in the region, it is considered as a new endemic focus in Iran. © 2012 Blackwell Verlag GmbH.

  16. Mapping of dihydropyridine binding residues in a less sensitive invertebrate L-type calcium channel (LCa v 1).

    PubMed

    Senatore, Adriano; Boone, Adrienne; Lam, Stanley; Dawson, Taylor F; Zhorov, Boris; Spafford, J David

    2011-01-01

    Invertebrate L-type calcium channel, LCa(v) 1, isolated from the pond snail Lymnaea stagnalis is nearly indistinguishable from mammalian Ca(v) 1.2 (α1C) calcium channel in biophysical characteristics observed in vitro. These L-type channels are likely constrained within a narrow range of biophysical parameters to perform similar functions in the snail and mammalian cardiovascular systems. What distinguishes snail and mammalian L-type channels is a difference in dihydropyridine sensitivity: 100 nM isradipine exhibits a significant block of mammalian Ca(v) 1.2 currents without effect on snail LCa(v)1 currents. The native snail channel serves as a valuable surrogate for validating key residue differences identified from previous experimental and molecular modeling work. As predicted, three residue changes in LCa(v)1 (N_3o18, F_3i10, and I_4i12) replaced with DHP-sensing residues in respective positions of Ca(v) 1.2, (Q_3o18, Y_3i10, and M_4i12) raises the potency of isradipine block of LCa(v)1 channels to that of mammalian Ca(v) 1.2. Interestingly, the single N_3o18_Q mutation in LCa(v) 1 channels lowers DHP sensitivity even further and the triple mutation bearing enhanced isradipine sensitivity, still retains a reduced potency of agonist, (S)-Bay K8644.

  17. Effects of chronic low level lead exposure on the physiology of individually identifiable neurons.

    PubMed

    Audesirk, G; Audesirk, T

    1983-01-01

    Although chronic exposure to lead has been correlated with a variety of behavioral and neurochemical deficits in humans and other mammals, little is known of the mechanisms of action of chronic lead at the level of the individual nerve cell. We have used the individually identifiable neurons of the freshwater pond snail Lymnaea stagnalis as a model system to investigate the effects of chronic low level (5 microM) lead exposure on neuronal physiology. Thirteen neuronal parameters were measured with intracellular microelectrode recording in each of six different identifiable neurons or homogeneous neuron clusters. Results were analyzed by a multivariate analysis of variance (MANOVA). MANOVA analysis indicates that there is a significant overall effect of lead exposure (p = 0.0001) and a significant interaction between lead and neuron type (p = 0.01). In most neuron types, chronic lead causes an increase in the resting potential, a slowing of recovery of the membrane potential after the undershoot of a spike, a decrease in spontaneous spiking activity, and a decrease in the input resistance. Lead also has differential effects on identifiable neurons, depressing excitability in some neuron types while not altering excitability in others.

  18. About a Snail, a Toad, and Rodents: Animal Models for Adaptation Research

    PubMed Central

    Roubos, Eric W.; Jenks, Bruce G.; Xu, Lu; Kuribara, Miyuki; Scheenen, Wim J. J. M.; Kozicz, Tamás

    2010-01-01

    Neural adaptation mechanisms have many similarities throughout the animal kingdom, enabling to study fundamentals of human adaptation in selected animal models with experimental approaches that are impossible to apply in man. This will be illustrated by reviewing research on three of such animal models, viz. (1) the egg-laying behavior of a snail, Lymnaea stagnalis: how one neuron type controls behavior, (2) adaptation to the ambient light condition by a toad, Xenopus laevis: how a neuroendocrine cell integrates complex external and neural inputs, and (3) stress, feeding, and depression in rodents: how a neuronal network co-ordinates different but related complex behaviors. Special attention is being paid to the actions of neurochemical messengers, such as neuropeptide Y, urocortin 1, and brain-derived neurotrophic factor. While awaiting new technological developments to study the living human brain at the cellular and molecular levels, continuing progress in the insight in the functioning of human adaptation mechanisms may be expected from neuroendocrine research using invertebrate and vertebrate animal models. PMID:22649351

  19. Ligand-binding domain of an α7-nicotinic receptor chimera and its complex with agonist

    PubMed Central

    Li, Shu-Xing; Huang, Sun; Bren, Nina; Noridomi, Kaori; Dellisanti, Cosma D; Sine, Steven M; Chen, Lin

    2012-01-01

    The α7 acetylcholine receptor (AChR) mediates pre- and postsynaptic neurotransmission in the central nervous system and is a potential therapeutic target in neurodegenerative, neuropsychiatric and inflammatory disorders. We determined the crystal structure of the extracellular domain of a receptor chimera constructed from the human α7 AChR and Lymnaea stagnalis acetylcholine binding protein (AChBP), which shares 64% sequence identity and 71% similarity with native α7. We also determined the structure with bound epibatidine, a potent AChR agonist. Comparison of the structures revealed molecular rearrangements and interactions that mediate agonist recognition and early steps in signal transduction in α7 AChRs. The structures further revealed a ring of negative charge within the central vestibule, poised to contribute to cation selectivity. Structure-guided mutational studies disclosed distinctive contributions to agonist recognition and signal transduction in α7 AChRs. The structures provide a realistic template for structure-aided drug design and for defining structure–function relationships of α7 AChRs. PMID:21909087

  20. Molecular and morphological evidence for three species of Diplostomum (Digenea: Diplostomidae), parasites of fishes and fish-eating birds in Spain.

    PubMed

    Pérez-del-Olmo, Ana; Georgieva, Simona; Pula, Héctor J; Kostadinova, Aneta

    2014-11-12

    Recent molecular studies have revealed high species diversity of Diplostomum in central and northern Europe. However, our knowledge of the distribution of Diplostomum spp. in the southern distributional range in Europe of the snail intermediate hosts (Lymnaea stagnalis and Radix spp.) is rather limited. This study aims to fill this gap in our knowledge using molecular and morphological evidence. Nineteen fish species and six fish-eating bird species were sampled opportunistically in three regions (Catalonia, Extremadura and Aragon) in Spain. All isolates of Diplostomum spp. were characterised morphologically and molecularly. Partial sequences of the barcode region of the cox1 mitochondrial gene and complete sequences of the ribosomal ITS1-5.8S-ITS2 gene cluster were used for molecular identification of the isolates. Integrated morphological and molecular analyses demonstrated the presence of three species among the larval and adult isolates of Diplostomum spp. sampled in Spain: Diplostomum spathaceum (in fish and birds), D. pseudospathaceum (in birds) and Diplostomum sp. (in fish) referred to as Clade Q sensu Georgieva et al. (Int J Parasitol, 43:57-72, 2013). We detected ten cox1 haplotypes among the isolates of D. spathaceum with only one haplotype shared with adult isolates from central and northern Europe. No specific geographic pattern of the distribution of the novel haplotypes was found. This first molecular exploration of the diversity of Diplostomum spp. in southern Europe indicates much lower species richness compared with the northern regions of Europe.

  1. Retinoic acid induces neurite outgrowth and growth cone turning in invertebrate neurons.

    PubMed

    Dmetrichuk, Jennifer M; Carlone, Robert L; Spencer, Gaynor E

    2006-06-01

    Identification of molecules involved in neurite outgrowth during development and/or regeneration is a major goal in the field of neuroscience. Retinoic acid (RA) is a biologically important metabolite of vitamin A that acts as a trophic factor and has been implicated in neurite outgrowth and regeneration in many vertebrate species. Although abundant in the CNS of many vertebrates, the precise role of RA in neural regeneration has yet to be determined. Moreover, very little information is available regarding the role of RA in invertebrate nervous systems. Here, we demonstrate for the first time that RA induces neurite outgrowth from invertebrate neurons. Using individually identified neurons isolated from the CNS of Lymnaea stagnalis, we demonstrated that a significantly greater proportion of cells produced neurite outgrowth in RA. RA also extended the duration of time that cells remained electrically excitable in vitro, and we showed that exogenously applied RA acted as a chemoattractive factor and induced growth cone turning toward the source of RA. This is the first demonstration that RA can induce turning of an individual growth cone. These data strongly suggest that the actions of RA on neurite outgrowth and cell survival are highly conserved across species.

  2. Different receptors mediate the electrophysiological and growth cone responses of an identified neuron to applied dopamine.

    PubMed

    Dobson, K S; Dmetrichuk, J M; Spencer, G E

    2006-09-15

    Neurotransmitters are among the many cues that may guide developing axons toward appropriate targets in the developing nervous system. We have previously shown in the mollusk Lymnaea stagnalis that dopamine, released from an identified pre-synaptic cell, differentially affects growth cone behavior of its target and non-target cells in vitro. Here, we describe a group of non-target cells that also produce an inhibitory electrophysiological response to applied dopamine. We first determined, using pharmacological blockers, which receptors mediate this physiological response. We demonstrated that the dopaminergic electrophysiological responses of non-target cells were sensitive to a D2 receptor antagonist, as are known target cell responses. However, the non-target cell receptors were linked to different G-proteins and intracellular signaling pathways than the target cell receptors. Despite the presence of a D2-like receptor at the soma, the growth cone collapse of these non-target cells was mediated by D1-like receptors. This study shows that different dopamine receptor sub-types mediated the inhibitory physiological and growth cone responses of an identified cell type. We therefore not only provide further evidence that D2- and D1-like receptors can be present on the same neuron in invertebrates, but also show that these receptors are likely involved in very different cellular functions.

  3. Natural selection on immune defense: A field experiment.

    PubMed

    Langeloh, Laura; Behrmann-Godel, Jasminca; Seppälä, Otto

    2017-02-01

    Predicting the evolution of phenotypic traits requires an understanding of natural selection on them. Despite its indispensability in the fight against parasites, selection on host immune defense has remained understudied. Theory predicts immune traits to be under stabilizing selection due to associated trade-offs with other fitness-related traits. Empirical studies, however, report mainly positive directional selection. This discrepancy could be caused by low phenotypic variation in the examined individuals and/or variation in host resource level that confounds trade-offs in empirical studies. In a field experiment where we maintained Lymnaea stagnalis snails individually in cages in a lake, we investigated phenotypic selection on two immune defense traits, phenoloxidase (PO)-like activity and antibacterial activity, in hemolymph. We used a diverse laboratory population and manipulated snail resource level by limiting their food supply. For six weeks, we followed immune activity, growth, and two fitness components, survival and fecundity of snails. We found that PO-like activity and growth were under stabilizing selection, while antibacterial activity was under positive directional selection. Selection on immune traits was mainly driven by variation in survival. The form of selection on immune defense apparently depends on the particular trait, possibly due to its importance for countering the present parasite community. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  4. A planar microelectrode array for simultaneous detection of electrically evoked dopamine release from distinct locations of a single isolated neuron.

    PubMed

    Patel, Bhavik Anil; Luk, Collin C; Leow, Pei Ling; Lee, Arthur J; Zaidi, Wali; Syed, Naweed I

    2013-05-21

    Neurotransmission is a key process of communication between neurons. Although much is known about this process and the influence it has on the function of the body, little is understood about the dynamics of signalling from structural regions of a single neuron. In this study we have fabricated and characterised a microelectrode array (MEA) which was utilised for simultaneous multi-site recordings of dopamine release from an isolated single neuron. The MEA consisted of gold electrodes that were created in plane with the insulation layer using a chemical mechanical planarization process. The detection limit for dopamine measurements was 11 ± 3 nM and all the gold electrodes performed in a consistent fashion during amperometric recordings of 100 nM dopamine. Fouling of the gold electrode was investigated, where no significant change in the current was observed over 4 hours when monitoring 100 nM dopamine. The MEA was accessed using freshly isolated dopaminergic somas from the pond snail, Lymnaea stagnalis, where electrically evoked dopamine release was clearly observed. Measurements were conducted at four structural locations of a single isolated neuron, where electrically evoked dopamine release was observed from the cell body, axonal regions and the terminal. Over time, the release of dopamine varied over the structural regions of the neuron. Such information can provide an insight into the signalling mechanism of neurons and how they potentially form synaptic connections.

  5. Effect of male accessory gland products on egg laying in gastropod molluscs.

    PubMed

    van Iersel, Sander; Swart, Elferra M; Nakadera, Yumi; van Straalen, Nico M; Koene, Joris M

    2014-06-22

    In internally fertilizing animals, seminal fluid is usually added to the spermatozoa, together forming the semen or ejaculate. Besides nourishing and activating sperm, the components in the seminal fluid can also influence female physiology to augment fertilization success of the sperm donor. While many studies have reported such effects in species with separate sexes, few studies have addressed this in simultaneously hermaphroditic animals. This video protocol presents a method to study effects of seminal fluid in gastropods, using a simultaneously hermaphroditic freshwater snail, the great pond snail Lymnaea stagnalis, as model organism. While the procedure is shown using complete prostate gland extracts, individual components (i.e., proteins, peptides, and other compounds) of the seminal fluid can be tested in the same way. Effects of the receipt of ejaculate components on egg laying can be quantified in terms of frequency of egg laying and more subtle estimates of female reproductive performance such as egg numbers within each egg masses. Results show that seminal fluid proteins affect female reproductive output in this simultaneous hermaphrodite, highlighting their importance for sexual selection.

  6. Coolidge effect in pond snails: male motivation in a simultaneous hermaphrodite

    PubMed Central

    Koene, Joris M; Ter Maat, Andries

    2007-01-01

    Background The simultaneously hermaphroditic pond snail, Lymnaea stagnalis, can mate in the male and female role, but within one copulation only one sexual role is performed at a time. Previous work has shown that male motivation is determined by the availability of seminal fluid in the prostate gland, which is detected via a nervous connection by the brain area controlling male behaviour. Based on this knowledge, patterns of sexual role alternations within mating pairs can be explained. Results The data presented here reveal that these snails can donate and receive sperm several times within 24 hours, and that they have increased mating rates in larger groups (i.e. more mating opportunities). For mating pairs we show, by introducing novel mating partners after copulation, that animals do inseminate new partners, while they are no longer motivated to inseminate their original partners. Conclusion Our findings provide the first direct evidence for higher motivation in a hermaphrodite to copulate when a new partner is encountered. This Coolidge effect seems to be attenuated when mucus trails are excluded, which suggests that a chemical or textural cue may be responsible for mediating this response to sperm competition. PMID:17986351

  7. Inhibition of Nicotinic Acetylcholine Receptors, a Novel Facet in the Pleiotropic Activities of Snake Venom Phospholipases A2

    PubMed Central

    Vulfius, Catherine A.; Kasheverov, Igor E.; Starkov, Vladislav G.; Osipov, Alexey V.; Andreeva, Tatyana V.; Filkin, Sergey Yu.; Gorbacheva, Elena V.; Astashev, Maxim E.; Tsetlin, Victor I.; Utkin, Yuri N.

    2014-01-01

    Phospholipases A2 represent the most abundant family of snake venom proteins. They manifest an array of biological activities, which is constantly expanding. We have recently shown that a protein bitanarin, isolated from the venom of the puff adder Bitis arietans and possessing high phospholipolytic activity, interacts with different types of nicotinic acetylcholine receptors and with the acetylcholine-binding protein. To check if this property is characteristic to all venom phospholipases A2, we have studied the capability of these enzymes from other snakes to block the responses of Lymnaea stagnalis neurons to acetylcholine or cytisine and to inhibit α-bungarotoxin binding to nicotinic acetylcholine receptors and acetylcholine-binding proteins. Here we present the evidence that phospholipases A2 from venoms of vipers Vipera ursinii and V. nikolskii, cobra Naja kaouthia, and krait Bungarus fasciatus from different snake families suppress the acetylcholine- or cytisine-elicited currents in L. stagnalis neurons and compete with α-bungarotoxin for binding to muscle- and neuronal α7-types of nicotinic acetylcholine receptor, as well as to acetylcholine-binding proteins. As the phospholipase A2 content in venoms is quite high, under some conditions the activity found may contribute to the deleterious venom effects. The results obtained suggest that the ability to interact with nicotinic acetylcholine receptors may be a general property of snake venom phospholipases A2, which add a new target to the numerous activities of these enzymes. PMID:25522251

  8. Effects of Aβ exposure on long-term associative memory and its neuronal mechanisms in a defined neuronal network

    PubMed Central

    Ford, Lenzie; Crossley, Michael; Williams, Thomas; Thorpe, Julian R.; Serpell, Louise C.; Kemenes, György

    2015-01-01

    Amyloid beta (Aβ) induced neuronal death has been linked to memory loss, perhaps the most devastating symptom of Alzheimer’s disease (AD). Although Aβ-induced impairment of synaptic or intrinsic plasticity is known to occur before any cell death, the links between these neurophysiological changes and the loss of specific types of behavioral memory are not fully understood. Here we used a behaviorally and physiologically tractable animal model to investigate Aβ-induced memory loss and electrophysiological changes in the absence of neuronal death in a defined network underlying associative memory. We found similar behavioral but different neurophysiological effects for Aβ 25-35 and Aβ 1-42 in the feeding circuitry of the snail Lymnaea stagnalis. Importantly, we also established that both the behavioral and neuronal effects were dependent upon the animals having been classically conditioned prior to treatment, since Aβ application before training caused neither memory impairment nor underlying neuronal changes over a comparable period of time following treatment. PMID:26024049

  9. [Osphradial chemosensory organ as a probable trigger of the cardiac system adaptive reaction to the effect of heavy metals in aquatic mollusks].

    PubMed

    Kamardin, N N; Lubimtsev, V A; Kornienko, E L; Udalova, G P; Kholodkevich, S V; Apostolov, S A

    2015-01-01

    The responses of osphradium in the fresh-water mollusk Viviparus sp. and single osphradial neurons in the pond snail Lymnaea stagnalis to L-glutamine and L-asparagine as well as the changes in these responses under the effect of heavy metals (Cu, Cd) were recorded electrophysiologically. The functional connections of osphradium with the identified neurons of the central pattern generator of respiratory movements and cardiac activity as well as the modification of these connections under the effect of short-term application of HgCl2 solution on the snail's osphradium were investigated. The cardiac rhythm in the mollusk Littorina littorea under the effect of Cu ions was registered non-invasively in long-lasting experiments. The dose-dependent short-term effects of heavy metals changes after osphradium injury were revealed. The implication of osphradium in adaptive reactions of the cardiac system in aquatic mollusks to the environmental heavy metal pollution is suggested. The dependence of cardiac rhythm on the degree of accumulation of copper ions in the mollusk tissues was detected. The results obtained are essential for unraveling neural mechanisms and pathways allowing heavy metals to affect the functional state of hydrobionts, particularly, the cardiac activity frequency characteristics of which are widely used as informative biomarkers to assess physiological condition of aquatic invertebrates.

  10. A role for host-parasite interactions in the horizontal transfer of transposons across phyla.

    PubMed

    Gilbert, Clément; Schaack, Sarah; Pace, John K; Brindley, Paul J; Feschotte, Cédric

    2010-04-29

    Horizontal transfer (HT), or the passage of genetic material between non-mating species, is increasingly recognized as an important force in the evolution of eukaryotic genomes. Transposons, with their inherent ability to mobilize and amplify within genomes, may be especially prone to HT. However, the means by which transposons can spread across widely diverged species remain elusive. Here we present evidence that host-parasite interactions have promoted the HT of four transposon families between invertebrates and vertebrates. We found that Rhodnius prolixus, a triatomine bug feeding on the blood of various tetrapods and vector of Chagas' disease in humans, carries in its genome four distinct transposon families that also invaded the genomes of a diverse, but overlapping, set of tetrapods. The bug transposons are approximately 98% identical and cluster phylogenetically with those of the opossum and squirrel monkey, two of its preferred mammalian hosts in South America. We also identified one of these transposon families in the pond snail Lymnaea stagnalis, a cosmopolitan vector of trematodes infecting diverse vertebrates, whose ancestral sequence is nearly identical and clusters with those found in Old World mammals. Together these data provide evidence for a previously hypothesized role of host-parasite interactions in facilitating HT among animals. Furthermore, the large amount of DNA generated by the amplification of the horizontally transferred transposons supports the idea that the exchange of genetic material between hosts and parasites influences their genomic evolution.

  11. The conformation of acetylcholine at its target site in the membrane-embedded nicotinic acetylcholine receptor

    PubMed Central

    Williamson, P. T. F.; Verhoeven, A.; Miller, K. W.; Meier, B. H.; Watts, A.

    2007-01-01

    The conformation of the neurotransmitter acetylcholine bound to the fully functional nicotinic acetylcholine receptor embedded in its native membrane environment has been characterized by using frequency-selective recoupling solid-state NMR. Six dipolar couplings among five resolved 13C-labeled atoms of acetylcholine were measured. Bound acetylcholine adopts a bent conformation characterized with a quaternary ammonium-to-carbonyl distance of 5.1 Å. In this conformation, and with its orientation constrained to that previously determined by us, the acetylcholine could be docked satisfactorily in the agonist pocket of the agonist-bound, but not the agonist-free, crystal structure of a soluble acetylcholine-binding protein from Lymnaea stagnali. The quaternary ammonium group of the acetylcholine was determined to be within 3.9 Å of five aromatic residues and its acetyl group close to residues C187/188 of the principle and residue L112 of the complementary subunit. The observed >CO chemical shift is consistent with H bonding to the nicotinic acetylcholine receptor residues γY116 and δT119 that are homologous to L112 in the soluble acetylcholine-binding protein. PMID:17989232

  12. Left-right asymmetric expression of dpp in the mantle of gastropods correlates with asymmetric shell coiling

    PubMed Central

    2013-01-01

    Background Various shapes of gastropod shells have evolved ever since the Cambrian. Although theoretical analyses of morphogenesis exist, the molecular basis of shell development remains unclear. We compared expression patterns of the decapentaplegic (dpp) gene in the shell gland and mantle tissues at various developmental stages between coiled-shell and non-coiled-shell gastropods. Results We analyzed the expression patterns of dpp for the two limpets Patella vulgata and Nipponacmea fuscoviridis, and for the dextral wild-type and sinistral mutant lineage of the pond snail Lymnaea stagnalis. The limpets had symmetric expression patterns of dpp throughout ontogeny, whereas in the pond snail, the results indicated asymmetric and mirror image patterns between the dextral and sinistral lineages. Conclusion We hypothesize that Dpp induces mantle expansion, and the presence of a left/right asymmetric gradient of the Dpp protein causes the formation of a coiled shell. Our results provide a molecular explanation for shell, coiling including new insights into expression patterns in post-embryonic development, which should aid in understanding how various shell shapes are formed and have evolved in the gastropods. PMID:23711320

  13. Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon.

    PubMed

    Lewis, Ariel S; Huntington, Thomas G; Marvin-DiPasquale, Mark C; Amirbahman, Aria

    2016-05-01

    Wetlands are hotspots for production of toxic methylmercury (MeHg) that can bioaccumulate in the food web. The objective of this study was to determine whether the application of zero-valent iron (ZVI) or granular activated carbon (GAC) to wetland sediment could reduce MeHg production and bioavailability to benthic organisms. Field mesocosms were installed in a wetland fringing Hodgdon Pond (Maine, USA), and ZVI and GAC were applied. Pore-water MeHg concentrations were lower in treated compared with untreated mesocosms; however, sediment MeHg, as well as total Hg (THg), concentrations were not significantly different between treated and untreated mesocosms, suggesting that smaller pore-water MeHg concentrations in treated sediment were likely due to adsorption to ZVI and GAC, rather than inhibition of MeHg production. In laboratory experiments with intact vegetated sediment clumps, amendments did not significantly change sediment THg and MeHg concentrations; however, the mean pore-water MeHg and MeHg:THg ratios were lower in the amended sediment than the control. In the laboratory microcosms, snails (Lymnaea stagnalis) accumulated less MeHg in sediment treated with ZVI or GAC. The study results suggest that both GAC and ZVI have potential for reducing MeHg bioaccumulation in wetland sediment.

  14. Biogeochemical Controls of Uranium Bioavailability from the Dissolved Phase in Natural Freshwaters.

    PubMed

    Croteau, Marie-Noële; Fuller, Christopher C; Cain, Daniel J; Campbell, Kate M; Aiken, George

    2016-08-02

    To gain insights into the risks associated with uranium (U) mining and processing, we investigated the biogeochemical controls of U bioavailability in the model freshwater species Lymnaea stagnalis (Gastropoda). Bioavailability of dissolved U(VI) was characterized in controlled laboratory experiments over a range of water hardness, pH, and in the presence of complexing ligands in the form of dissolved natural organic matter (DOM). Results show that dissolved U is bioavailable under all the geochemical conditions tested. Uranium uptake rates follow first order kinetics over a range encompassing most environmental concentrations. Uranium uptake rates in L. stagnalis ultimately demonstrate saturation uptake kinetics when exposure concentrations exceed 100 nM, suggesting uptake via a finite number of carriers or ion channels. The lack of a relationship between U uptake rate constants and Ca uptake rates suggest that U does not exclusively use Ca membrane transporters. In general, U bioavailability decreases with increasing pH, increasing Ca and Mg concentrations, and when DOM is present. Competing ions did not affect U uptake rates. Speciation modeling that includes formation constants for U ternary complexes reveals that the aqueous concentration of dicarbonato U species (UO2(CO3)2(-2)) best predicts U bioavailability to L. stagnalis, challenging the free-ion activity model postulate.

  15. Brefeldin A or monensin inhibits the 3D organizer in gastropod, polyplacophoran, and scaphopod molluscs.

    PubMed

    Gonzales, Eric E; van der Zee, Maurijn; Dictus, Wim J A G; van den Biggelaar, Jo

    2007-02-01

    In molluscs, the 3D vegetal blastomere acts as a developmental signaling center, or organizer, and is required to establish bilateral symmetry in the embryo. 3D is similar to organizing centers in other metazoans, but detailed comparisons are difficult, in part because its organizing function is poorly understood. To elucidate 3D function in a standardized fashion, we used monensin and brefeldin A (BFA) to rapidly and reversibly interfere with protein processing and secretion, thereby inhibiting the signaling interactions that underlie its specification and patterning. In the gastropods, Patella vulgata and Lymnaea stagnalis, the polyplacophoran, Mopalia muscosa, and the scaphopod, Antalis entalis, treatments initiated before the organizer-dependent onset of bilateral cleavage resulted in radialization of subsequent development. In radialized P. vulgata, L. stagnalis, and M. muscosa, organizer specification was blocked, and embryos failed to make the transition to bilateral cleavage. In all four species, the subsequent body plan was radially symmetric and was similarly organized about a novel aboral-oral axis. Our results demonstrate that brefeldin A (BFA) and monensin can be used to inhibit 3D's organizing function in a comparative fashion and that, at least in M. muscosa, the organizer-dependent developmental architecture of the embryo predicts subsequent patterns of morphogenetic movements in gastrulation and, ultimately, the layout of the adult body plan.

  16. Simultaneous analysis of multiple neurotransmitters by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry.

    PubMed

    Tufi, Sara; Lamoree, Marja; de Boer, Jacob; Leonards, Pim

    2015-05-22

    Neurotransmitters are endogenous metabolites that allow the signal transmission across neuronal synapses. Their biological role is crucial for many physiological functions and their levels can be changed by several diseases. Because of their high polarity, hydrophilic interaction liquid chromatography (HILIC) is a promising tool for neurotransmitter analysis. Due to the large number of HILIC stationary phases available, an evaluation of the column performances and retention behaviors has been performed on five different commercial HILIC packing materials (silica, amino, amide and two zwitterionic stationary phases). Several parameters like the linear correlation between retention and the distribution coefficient (logD), the separation factor k and the column resolution Rs have been investigated and the column performances have been visualized with a heat map and hierarchical clustering analysis. An optimized and validated HILIC-MS/MS method based on the ZIC-cHILIC column is proposed for the simultaneous detection and quantification of twenty compounds consisting of neurotransmitters, precursors and metabolites: 3-methoxytyramine (3-MT), 5-hydroxyindoleacetic acid (5-HIAA), 5-hydroxy-L-tripthophan, acetylcholine, choline, L-3,4-dihydroxyphenylalanine (L-DOPA), dopamine, epinephrine, γ-aminobutyric acid (GABA), glutamate, glutamine, histamine, histidine, L-tryptophan, L-tyrosine, norepinephrine, normetanephrine, phenylalanine, serotonin and tyramine. The method was applied to neuronal metabolite profiling of the central nervous system of the freshwater snail Lymnaea stagnalis. This method is suitable to explore neuronal metabolism and its alteration in different biological matrices.

  17. The definitive and intermediate hosts of Fasciola hepatica in the natural watercress beds in central France.

    PubMed

    Rondelaud, D; Vignoles, P; Abrous, M; Dreyfuss, G

    2001-06-01

    Field investigations were carried out over a two-year period in 52 natural watercress beds located in the Limousin region of central France to list the mammal and bird species that frequented these sites. This enabled detection of the definitive hosts of Fasciola hepatica and determination of the prevalence of natural infection in snails. A total of 13 mammal and five bird species were listed in these watercress beds. Adult flukes were found in Lepus capensis (39.2%), Oryctolagus cuniculus (42.0%), and Sylvilagus floridanus (25.0%). No infection with F. hepatica was noted in the five species of rodents studied. Snails infected with F. hepatica were found in 14 watercress beds. The global prevalence of natural infection was 1.1% in Lymnaea truncatula and 0.3% in L. glabra. Among the other trematode larval forms detected, the most frequent was Haplometra cylindracea (0.5%). In the Limousin region, the presence of hares and rabbits in watercress beds ensured the continuation of the F. hepatica life cycle and permitted the subsequent infection of humans when this wild watercress was eaten.

  18. Species diversity of Plagiorchis Lühe, 1899 (Digenea: Plagiorchiidae) in lymnaeid snails from freshwater ecosystems in central Europe revealed by molecules and morphology.

    PubMed

    Zikmundová, Jana; Georgieva, Simona; Faltýnková, Anna; Soldánová, Miroslava; Kostadinova, Aneta

    2014-05-01

    Larval stages of Plagiorchis spp. are both ubiquitous and ecologically important parasites in snail populations of freshwater ecosystems in Europe. However, difficulties in distinguishing the morphologically similar cercariae used for species identification, may lead to underestimation of species diversity. In this study, 38 isolates of Plagiorchis spp. infecting two lymnaeid snails, Lymnaea stagnalis (L.) and Radix auricularia (L.), in five central European freshwater ecosystems were subjected to morphological and molecular assessment. Five morphologically homogeneous and genetically distinct lineages of Plagiorchis spp. were identified via matching molecular data for the mitochondrial cytochrome c oxidase subunit I (cox1) gene with detailed morphological and morphometric data of the cercariae. Comparative sequence analysis using partial 28S rDNA and ITS1-5.8S-ITS2 sequences revealed that three distinct cox1 lineages are conspecific with Plagiorchis elegans (Rudolphi, 1802), P. maculosus (Rudolphi, 1802) and P. koreanus Ogata, 1938, respectively, whereas the lineage identified based on cercarial morphology as P. neomidis Brendow, 1970 plus a single isolate that could not be assigned to a described species, did not match any of the available sequences for Plagiorchis spp. A key to the cercariae of Plagiorchis spp. parasitising lymnaeid populations in central Europe is provided to facilitate identification.

  19. Occurrence of Fasciola hepatica (Linnaeus, 1758) in capybara (Hydrochoerus hydrochaeris) (Linnaeus, 1766) in Minas Gerais, Brazil.

    PubMed

    Dracz, Ruth Massote; Ribeiro, Vinicius Marques Antunes; Pereira, Cintia Aparecida de Jesus; Lima, Walter Dos Santos

    2016-01-01

    Fasciola hepatica is a parasite that affects the hepatic ducts of several species of domestic and wild vertebrates, causing huge economic losses to livestock rearing worldwide. Reports on occurrences of F. hepatica in capybaras are an important epidemiological aspect of this disease, since these rodents can be a source of contamination for other animals and humans. In the present study, conducted in a rural area of the municipality of Confins, Minas Gerais, fresh feces from capybaras were collected from the ground near a lagoon at the edge of the Ribeirão da Mata river. These were examined using the technique of four metal sieves. F. hepatica eggs were recovered. This trematode species was confirmed by observing morphological characteristics and measuring the eggs recovered from the capybara feces, and through experimental infection of Lymnaea columella (Say, 1817) by miracidia from these eggs and subsequent infection of C57/BL06 mice with metacercariae originating from these infected mollusks. The data suggest the occurrence of natural cycle of F. hepatica in this region and provide a warning that expansion of the geographical distribution of this parasite by means of this rodent is possible. It is therefore important to adopting measures for epidemiological control of this helminthiasis.

  20. Channel opening motion of alpha7 nicotinic acetylcholine receptor as suggested by normal mode analysis.

    PubMed

    Cheng, Xiaolin; Lu, Benzhuo; Grant, Barry; Law, Richard J; McCammon, J Andrew

    2006-01-13

    The gating motion of the human nicotinic acetylcholine receptor (nAChR) alpha7 was investigated with normal mode analysis (NMA) of two homology models. The first model, referred to as model I, was built from both the Lymnaea stagnalis acetylcholine binding protein (AChBP) and the transmembrane (TM) domain of the Torpedo marmorata nAChR. The second model, referred to as model C, was based solely on the recent electron microscopy structure of the T. marmorata nAChR. Despite structural differences, both models exhibit nearly identical patterns of flexibility and correlated motions. In addition, both models show a similar global twisting motion that may represent channel gating. The similar results obtained for the two models indicate that NMA is most sensitive to the contact topology of the structure rather than its finer detail. The major difference between the low-frequency motions sampled for the two models is that a symmetrical pore-breathing motion, favoring channel opening, is present as the second most dominant motion in model I, whilst largely absent from model C. The absence of this mode in model C can be attributed to its less symmetrical architecture. Finally, as a further goal of the present study, an approximate open channel model, consistent with many experimental findings, has been produced.

  1. First record of a rare transversotrematid cercaria larva (Trematoda: Digenea) from Rajasthan, India: focus on seasonal occurrence and host-specificity of diverse cercariae.

    PubMed

    Choubisa, Shanti Lal; Jaroli, Vishva Jeet; Sheikh, Zulfiya

    2017-06-01

    During the survey of freshwater snail hosts and their digenean larval trematode parasites, a rare cercaria larva belonging to family Transversotrematidae and subclass Digenea (Trematoda) was recovered from the snail species Melanoides striatella tuberculata inhabiting perennial Som river of Udaipur district, Rajasthan, India. More than 28 % mature specimens of these snails were found to be infected with transversotrematid cercaria larvae in the spring season. Body of this cercaria is large, bowl-shaped, biocellate, spinose, transparent and laterally extended having two pigmented eye spots, two hold fast organs extended from the junction of body and tail, large tail with two foliated furcal rami, and cyclocoel intestinal caeca. As far as the authors are aware, this is the first record of a transversotrematid larva from Rajasthan, India. Simultaneously, other forms of cercariae viz., amphistome, echinostome, monostome, gymnocephalous, furcocercous and xiphidiocercous cercariae were also recovered from fifteen species of pulmonate and operculate snails including Lymnaea acuminata f. patula, L. acuminata f. chlamys, L. acuminata f. typica, L. acuminata f. rufescens, L. luteola f. australis, L. luteola f. typica, L. luteola f. impura, Planorbis (Indoplanorbis) exustus, and Anisus (Gyraulus) convexiusculus, Faunus ater, Melania (Plotia) scabra, Thiara (Tarebia) lineata, Melanoides striatella tuberculata, Vivipara bengalensis race gigantica and V. bengalensis race mandiensis. The seasonal occurrence and host-specificity of diverse trematode cercaria larvae are also discussed besides the first record of a rare transversotrematid cercaria larva from Rajasthan, India.

  2. Structural and Population Polymorphism of RT-Like Sequences in Avian Schistosomes Trichobilharzia szidati (Platyhelminthes: Digenea: Schistosomatidae).

    PubMed

    Semyenova, S K; Chrisanfova, G G; Guliaev, A S; Yesakova, A P; Ryskov, A P

    2015-01-01

    Recently we developed the genus-specific markers of the avian schistosomes of the genus Trichobilharzia, the causative agents of human cercarial dermatitis. The 7 novel genome sequences of T. franki, T. regenti, and T. szidati revealed similarity with genome repeat region of African schistosome Schistosoma mansoni. In the present work we analyzed the 37 new T. szidati sequences to study intragenome variability and host specificity for the parasite from three localities of East Europe. DNAs were isolated from cercariae or single sporocysts obtained from 6 lymnaeid snails Lymnaea stagnalis and L. palustris from Belarus and Russia. All sequences formed three diverged groups, one of which consists of the sequences with multiple deletions; other groups involved two paralogous copies with stop codons and frameshift mutations. Strong association between geographical distribution and snail host specificity cannot be established. All studied sequences have homology with the reverse transcriptase domain (RT) of Penelope-like elements (PLE) of S. mansoni and S. japonicum and new members of RT family were identified. We proposed that three diverged groups RT sequences of T. szidati are results of duplication or transposition of PLE during parasite evolution. Implications of the retroelement dynamics in the life history of avian schistosomes are discussed.

  3. Invertebrate grazers affect metal/metalloid fixation during litter decomposition.

    PubMed

    Schaller, Jörg; Brackhage, Carsten

    2015-01-01

    Plant litter and organic sediments are main sinks for metals and metalloids in aquatic ecosystems. The effect of invertebrates as key species in aquatic litter decomposition on metal/metalloid fixation by organic matter is described only for shredders, but for grazers as another important animal group less is known. Consequently, a laboratory batch experiment was conducted to examine the effect of invertebrate grazers (Lymnaea stagnalis L.) on metal/metalloid fixation/remobilization during aquatic litter decomposition. It could be shown that invertebrate grazers facilitate significantly the formation of smaller sizes of particulate organic matter (POM), as shown previously for invertebrate shredders. The metal/metalloid binding capacity of these smaller particles of POM is higher compared to leaf litter residuals. But element enrichment is not as high as shown previously for the effect by invertebrate shredders. Invertebrate grazers enhance also the mobilization of selected elements to the water, in the range also proven for invertebrate shredders but different for the different elements. Nonetheless invertebrate grazers activity during aquatic litter decomposition leads to a metal/metalloid fixation into leaf litter as part of sediment organic matter. Hence, the effect of invertebrate grazers on metal/metalloid fixation/remobilization contrasts partly with former assessments revealing the possibility of an enhanced metal/metalloid fixation.

  4. Transcriptome analysis of the Octopus vulgaris central nervous system.

    PubMed

    Zhang, Xiang; Mao, Yong; Huang, Zixia; Qu, Meng; Chen, Jun; Ding, Shaoxiong; Hong, Jingni; Sun, Tiantian

    2012-01-01

    Cephalopoda are a class of Mollusca species found in all the world's oceans. They are an important model organism in neurobiology. Unfortunately, the lack of neuronal molecular sequences, such as ESTs, transcriptomic or genomic information, has limited the development of molecular neurobiology research in this unique model organism. With high-throughput Illumina Solexa sequencing technology, we have generated 59,859 high quality sequences from 12,918,391 paired-end reads. Using BLASTx/BLASTn, 12,227 contigs have blast hits in the Swissprot, NR protein database and NT nucleotide database with E-value cutoff 1e(-5). The comparison between the Octopus vulgaris central nervous system (CNS) library and the Aplysia californica/Lymnaea stagnalis CNS ESTs library yielded 5.93%/13.45% of O. vulgaris sequences with significant matches (1e(-5)) using BLASTn/tBLASTx. Meanwhile the hit percentage of the recently published Schistocerca gregaria, Tilapia or Hirudo medicinalis CNS library to the O. vulgaris CNS library is 21.03%-46.19%. We constructed the Phylogenetic tree using two genes related to CNS function, Synaptotagmin-7 and Synaptophysin. Lastly, we demonstrated that O. vulgaris may have a vertebrate-like Blood-Brain Barrier based on bioinformatic analysis. This study provides a mass of molecular information that will contribute to further molecular biology research on O. vulgaris. In our presentation of the first CNS transcriptome analysis of O. vulgaris, we hope to accelerate the study of functional molecular neurobiology and comparative evolutionary biology.

  5. Morphology and life cycle of Apatemon hypseleotris species novum from Australia including metacercariae viability and excystment.

    PubMed

    Negm-Eldin, M; Davies, R W

    2002-07-01

    Experimental infection of pigeon squabs and rats with encysted metacercariae from the Western Carp gudgeon (Hypseleotris klunzingeri) showed them to be infected with a new strigeid trematode, Apatemon hypseleotris. Growth and development of A. hypseleotris in pigeons were significantly higher than in rats. Eggs appeared in pigeon faeces within 7-14 days; miracidia hatched within 15-21 days and in the snail Lymnaea tomentosa released within 21 days. Cercariae experimentally encysted in the leeches Helobdella papillornata (86.7%) and Alboglossiphonia australiensis (73.3%). In fish, encystation occurred in the abdominal cavity (100%) and muscles (40%) of Hypseleotris klunzingeri, in the abdominal cavity (80%) and head (30%) of Gambusia affinis and in the abdominal cavity (62.5%) of Oncorhynchus mykiss but no encystation occurred in Moenkhausia pittieri. Freezing (-7 degrees C for 3-7 days or -21 degrees C for 8-12 hours), chilling (6 degrees C for 12 days), boiling (3 minutes) or salting for 3-5 days of encysted metacercariae did not significantly reduce infectivity. In vitro excystation of metacercariae was achieved using pepsin followed by trypsin and/or bile salts.

  6. Fasciola hepatica infections in livestock flock, guanacos and coypus in two wildlife reserves in Argentina.

    PubMed

    Issia, Laura; Pietrokovsky, Silvia; Sousa-Figueiredo, José; Stothard, J Russell; Wisnivesky-Colli, Cristina

    2009-11-12

    Between autumn and spring 2006, a coprological survey was performed in two wildlife reserves located in the north of Argentine Patagonia to determine the prevalence of Fasciola hepatica and the number of parasite eggs per gram (epg) of feces in wild guanacos (Lama guanicoe), coypus (Myocastor coypus), and locally born and raised goats and sheep. Snails of the Family Lymnaeidae were collected in freshwater habitats, identified taxonomically and analyzed parasitologically. Prevalence of patent infection was 100% in sheep (n=69) and coypus (n=9), 84% in goats (n=20) and 0.5% in guanacos (n=224). No significant differences in epg were found among animals, but the median epg of coypus (160) and sheep (160) was higher than that of goats (80). For guanacos and goats, a negative binomial model estimating the population egg-count frequency could be fitted, while for coypus and sheep parasite egg-count frequencies trended toward a normal distribution, indicative of a more even, and much less aggregated distribution across sampled hosts. All snails (n=175) were Lymnaea truncatula and none of them was found infected. This is the first report of fascioliasis in free-ranging guanacos in Argentina. Coypu appears to be a major wildlife reservoir of F. hepatica, which was presumably introduced locally by livestock.

  7. [Fascioliasis: diagnosis, epidemiology and treatment].

    PubMed

    Carrada-Bravo, Teodoro

    2003-01-01

    Fascioliasis is a trematode, disease of liver and bile ducts of sheep, cattle, and other ruminants throughout the world that is caused by the fluke, Fasciola hepatica. Human infection has been reported in Mexico, Cuba, Puerto Rico, Chile, Peru, Uruguay, Brazil, Argentina, the US, Europe, eastern Africa, Japan and Australia. The parasite's miracidium invades one of the various Lymnaea water snail hosts. Infection results from ingestion of encysted metacercariae attached to raw watercress (Nasturtium officinale). Symptoms recorded from human cases included irregular fever, epigastric pain and abdominal tenderness, obstructive jaundice and leucocytosis with eosinophilea up to 60%. Specific diagnosis is based on recovery of the eggs in the patient's stool or from biliary tract drainage. Treatment is with emetine hydrochloride given intramusculary. Bithionol is given orally at a dosage of 30-50 mg/kg but on alternate days from 10 to 15 doses. Praziquantel is probably effective. Preventive measures include education of the public on mode of transmission of life cycle of the parasite, and dipping fresh watercress into boiling water for a few sec, or drying suspected watercress.

  8. In vitro studies of neuronal networks and synaptic plasticity in invertebrates and in mammals using multielectrode arrays.

    PubMed

    Massobrio, Paolo; Tessadori, Jacopo; Chiappalone, Michela; Ghirardi, Mirella

    2015-01-01

    Brain functions are strictly dependent on neural connections formed during development and modified during life. The cellular and molecular mechanisms underlying synaptogenesis and plastic changes involved in learning and memory have been analyzed in detail in simple animals such as invertebrates and in circuits of mammalian brains mainly by intracellular recordings of neuronal activity. In the last decades, the evolution of techniques such as microelectrode arrays (MEAs) that allow simultaneous, long-lasting, noninvasive, extracellular recordings from a large number of neurons has proven very useful to study long-term processes in neuronal networks in vivo and in vitro. In this work, we start off by briefly reviewing the microelectrode array technology and the optimization of the coupling between neurons and microtransducers to detect subthreshold synaptic signals. Then, we report MEA studies of circuit formation and activity in invertebrate models such as Lymnaea, Aplysia, and Helix. In the following sections, we analyze plasticity and connectivity in cultures of mammalian dissociated neurons, focusing on spontaneous activity and electrical stimulation. We conclude by discussing plasticity in closed-loop experiments.

  9. Outdoor experimental ponds (mesocosms) designed for long-term ecotoxicological studies in aquatic environment.

    PubMed

    Caquet, T; Lagadic, L; Jonot, O; Baturo, W; Kilanda, M; Simon, P; Le Bras, S; Echaubard, M; Ramade, F

    1996-07-01

    Outdoor artificial ponds (mesocosms) of 12 m3 were designed for long-term ecotoxicological studies. Sediment, macrophytes (Typha angustifolia and Elodea canadensis), and free and caged freshwater snails [Lymnaea palustris (Müller)] and wood lice (Asellus aquaticus L.) were collected in nearby natural ecosystems and introduced in the mesocosms. Sixty goldfish (Carassius auratus L.) were caged in each pond. Introduced species developed and reproduced in every mesocosm. Animal species (mainly insects and amphibians) spontaneously colonized the ponds, developed, and reproduced. The resulting communities qualitatively resemble those living in natural lentic systems in the surrounding area. Homogenity in physical and chemical conditions and in abundance of phytoplanktonic, periphytic, and macroinvertebrate communities between the different mesocosms was assessed during the stabilization period (8 months). Except for periphyton biomass, no divergent evolution was observed between the ponds. Mesocosm water was slightly eutrophic, alkaline (mean pH: 8.47 +/- 0.09), and moderately hard and mineralized. The homogenous and realistic environmental conditions and high ecological representativity of the outdoor experimental ponds were suitable for extensive ecotoxicological studies. Considerations on the choice and origin of introduced species and on possible interactive effects of the transfer of organisms from natural environments, maintainance conditions, and pollutant exposure are discussed.

  10. The Effect of Diet Mixing on a Nonselective Herbivore

    PubMed Central

    2016-01-01

    The balanced-diet hypothesis states that a diverse prey community is beneficial to consumers due to resource complementarity among the prey species. Nonselective consumer species cannot differentiate between prey items and are therefore not able to actively regulate their diet intake. We thus wanted to test whether the balanced-diet hypothesis is applicable to nonselective consumers. We conducted a laboratory experiment in which a nonselective model grazer, the freshwater gastropod Lymnaea stagnalis, was fed benthic green algae as single species or as a multi-species mixture and quantified the snails’ somatic growth rates and shell lengths over a seven-week period. Gastropods fed the mixed diet were found to exhibit a higher somatic growth rate than the average of the snails fed single prey species. However, growth on the multi-species mixture did not exceed the growth rate obtained on the best single prey species. Similar results were obtained regarding the animals’ shell height increase over time. The mixed diet did not provide the highest growth rate, which confirms our hypothesis. We thus suggest that the balanced-diet hypothesis is less relevant for non-selective generalist consumers, which needs to be considered in estimates of secondary production. PMID:27391787

  11. Predicting dietborne metal toxicity from metal influxes

    USGS Publications Warehouse

    Croteau, M.-N.; Luoma, S.N.

    2009-01-01

    Dietborne metal uptake prevails for many species in nature. However, the links between dietary metal exposure and toxicity are not well understood. Sources of uncertainty include the lack of suitable tracers to quantify exposure for metals such as copper, the difficulty to assess dietary processes such as food ingestion rate, and the complexity to link metal bioaccumulation and effects. We characterized dietborne copper, nickel, and cadmium influxes in a freshwater gastropod exposed to diatoms labeled with enriched stable metal isotopes. Metal influxes in Lymnaea stagnalis correlated linearly with dietborne metal concentrations over a range encompassing most environmental exposures. Dietary Cd and Ni uptake rate constants (kuf) were, respectively, 3.3 and 2.3 times higher than that for Cu. Detoxification rate constants (k detox) were similar among metals and appeared 100 times higher than efflux rate constants (ke). Extremely high Cu concentrations reduced feeding rates, causing the relationship between exposure and influx to deviate from linearity; i.e., Cu uptake rates leveled off between 1500 and 1800 nmol g-1 day-1. L. stagnalis rapidly takes up Cu, Cd, and Ni from food but detoxifies the accumulated metals, instead of reducing uptake or intensifying excretion. Above a threshold uptake rate, however, the detoxification capabilities of L. stagnalis are overwhelmed.

  12. A study on biological control of six fresh water snails of medical and veterinary importance.

    PubMed

    Abd-Allah, Karim F; Negm-Eldin, Mohsen M; Saleh, Mohamed H; El-Hamshary, Azza M S; El-Gozamy, Bothina M R; Aly, Nagwa S M

    2009-04-01

    This study evaluated the molluscicidal effect of Commiphora mnolmol oil extract (Myrrh), on control of six fresh water snails (Lymnaea natalensis, Bulinus truncatus, Biomphalaria alexandrina, Physa acuta, Melania tuberculata and Cleopatra bulimoides). Also, the extract effect on the egg masses of L. natalensis, B. truncatus, B. alexandrina and Ph. acuta was evaluated. Snails and egg masses were exposed at 16-20 degrees C to various concentrations (conc.). LD50 after 24 hours expo-sure were 264/132, 283/195, 230/252, 200/224, 241/246 & 241/246 ppm for young/adult of L. natalensis, B. truncatus, B. alexandrina, Ph. acuta, M. tuberculata and C. bulimnoides respectively. LDtoo after 24 hours exposure were 400/400 for L. natalensis, B. truncatus, B. alexandrina, M. tuberculata and C. bulimoides, and 300/300 for Ph. acuta. Also, complete mortality (100%) was achieved for the egg masses of L. natalensis, B. truncatus, B. alexandrina and Ph. acuta at concentrations of 300, 200, 300 & 400 ppm respectively. Lower concentrations gave the same results after longer exposure. LD100 of C. molmol oil extract (Myrrh) had a rapid lethal effect on the six snail species and their egg masses in high conc. of 300 & 400 ppm. Commiphora molmol is a promising plant to be included with the candidate plant molluscicides. The oil extract of this plant showed a remarkable molluscicidal activity against used snail species.

  13. [The radioactive contamination dynamics of water body ecosystems of different types in the Chernobyl atomic station alienation zone in Belarus].

    PubMed

    Golubev, A P; Sikorskiĭ, V G; Kalinin, V N; Afonin, V Iu; Chekan, G S

    2007-01-01

    The long-term (1986-2005) gamma-activity dynamics in dominating zoobenthos species and the bottom sediments in the inlet of Pripyat river and the non-flowing Perstok lake within the Chernobyl alienation zone was determined. Immediately after the accident (1986-1987) zoonehthos y-activity achieved the maximal values (up to 300-1100 kBq/kg) and after that began to decline steadily due to natural decay of man-caused radionuclides of "Chernobyl origin". Up to summer 2005 gastropod mollusks gamma-activity (Lymnaea stagnalis, Viviparus viviparus) approached to the natural level (less than 6 Bq/kg) in the inlet of Pripyat river, but it remained at the very high level up to 979-1638 Bq/kg in the Perstok lake. The positive correlation between gamma-activity of mollusks and bottom sediments has been established. In turn, the long-term variations of atmospheric precipitate amounts which wash down radionuclides from surrounding territories to water bodies and the amounts of annual flow of the Pripyat river as well as shoreline position changes in water bodies within the Chernobyl alienation zone influence on these values too.

  14. α-Conotoxin OmIA Is a Potent Ligand for the Acetylcholine-binding Protein as Well as α3β2 and α7 Nicotinic Acetylcholine Receptors*

    PubMed Central

    Talley, Todd T.; Olivera, Baldomero M.; Han, Kyou-Hoon; Christensen, Sean B.; Dowell, Cheryl; Tsigelny, Igor; Ho, Kwok-Yiu; Taylor, Palmer; McIntosh, J. Michael

    2016-01-01

    The molluskan acetylcholine-binding protein (AChBP) is a homolog of the extracellular binding domain of the pentameric ligand-gated ion channel family. AChBP most closely resembles the α-subunit of nicotinic acetylcholine receptors and in particular the homomeric α7 nicotinic receptor. We report the isolation and characterization of an α-conotoxin that has the highest known affinity for the Lymnaea AChBP and also potently blocks the α7 nAChR subtype when expressed in Xenopus oocytes. Remarkably, the peptide also has high affinity for the α3β2 nAChR indicating that α-conotoxin OmIA in combination with the AChBP may serve as a model system for understanding the binding determinants of α3β2 nAChRs. α-Conotoxin OmIA was purified from the venom of Conus omaria. It is a 17-amino-acid, two-disulfide bridge peptide. The ligand is the first α-conotoxin with higher affinity for the closely related receptor subtypes, α3β2 versus α6β2, and selectively blocks these two subtypes when compared with α2β2, α4β2, and α1β1δε nAChRs. PMID:16803900

  15. The role of synaptotagmin I C2A calcium-binding domain in synaptic vesicle clustering during synapse formation

    PubMed Central

    Gardzinski, Peter; Lee, David W K; Fei, Guang-He; Hui, Kwokyin; Huang, Guan J; Sun, Hong-Shuo; Feng, Zhong-Ping

    2007-01-01

    Synaptic vesicles aggregate at the presynaptic terminal during synapse formation via mechanisms that are poorly understood. Here we have investigated the role of the putative calcium sensor synaptotagmin I in vesicle aggregation during the formation of soma–soma synapses between identified partner cells using a simple in vitro synapse model in the mollusc Lymnaea stagnalis. Immunocytochemistry, optical imaging and electrophysiological recording techniques were used to monitor synapse formation and vesicle localization. Within 6 h, contact between appropriate synaptic partner cells up-regulated global synaptotagmin I expression, and induced a localized aggregation of synaptotagmin I at the contact site. Cell contacts between non-synaptic partner cells did not affect synaptotagmin I expression. Application of an human immunodeficiency virus type-1 transactivator (HIV-1 TAT)-tagged peptide corresponding to loop 3 of the synaptotagmin I C2A domain prevented synaptic vesicle aggregation and synapse formation. By contrast, a TAT-tagged peptide containing the calcium-binding motif of the C2B domain did not affect synaptic vesicle aggregation or synapse formation. Calcium imaging with Fura-2 demonstrated that TAT–C2 peptides did not alter either basal or evoked intracellular calcium levels. These results demonstrate that contact with an appropriate target cell is necessary to initiate synaptic vesicle aggregation during nascent synapse formation and that the initial aggregation of synaptic vesicles is dependent on loop 3 of the C2A domain of synaptotagmin I. PMID:17317745

  16. The distribution of Fasciola hepatica and Fasciola gigantica within southern Tanzania--constraints associated with the intermediate host.

    PubMed

    Walker, S M; Makundi, A E; Namuba, F V; Kassuku, A A; Keyyu, J; Hoey, E M; Prödohl, P; Stothard, J R; Trudgett, A

    2008-04-01

    In East Africa, Fasciola gigantica is generally the causative agent of fasciolosis but there have been reports of F. hepatica in cattle from highland regions of Kenya, Ethiopia, Uganda and Zaire. The topography of the Southern Highlands of Tanzania provides an environment where the climatic conditions exist for the sustenance of lymnaeid species capable of supporting both Fasciola hepatica and F. gigantica. Theoretically this would allow interaction between fasciolid species and the possible creation of hybrids. In this report we present molecular data confirming the existence of the snail, Lymnaea truncatula, at high altitude on the Kitulo Plateau of the Southern Highlands, Tanzania, along with morphometric and molecular data confirming the presence of F. hepatica in the corresponding area. At lower altitudes, where climatic conditions were unfavourable for the existence of L. truncatula, the presence of its sister species L. natalensis was confirmed by molecular data along with its preferred fasciolid parasite, F. gigantica. Analysis based on a 618 bp sequence of the 28S rRNA gene did not reveal the presence of hybrid fasciolids in our fluke samples.

  17. Inhibition of acetylcholinesterase and cytochrome oxidase activity in Fasciola gigantica cercaria by phytoconstituents.

    PubMed

    Sunita, Kumari; Habib, Maria; Kumar, P; Singh, Vinay Kumar; Husain, Syed Akhtar; Singh, D K

    2016-02-01

    Fasciolosis is an important cattle and human disease caused by Fasciola hepatica and Fasciola gigantica. One of the possible methods to control this problem is to interrupt the life cycle of Fasciola by killing its larva (redia and cercaria) in host snail. Molecular identification of cercaria larva of F. gigantica was done by comparing the nucleotide sequencing with adult F. gigantica. It was noted that nucleotide sequencing of cercaria larva and adult F. gigantica were 99% same. Every month during the year 2011-2012, in vivo treatment with 60% of 4 h LC50 of phyto cercaricides citral, ferulic acid, umbelliferone, azadirachtin and allicin caused significant inhibition of acetylcholinesterase (AChE) and cytochrome oxidase activity in the treated cercaria larva of F. gigantica. Whereas, activity of both enzymes were not significantly altered in the nervous tissues of vector snail Lymnaea acuminata exposed to same treatments. Maximum reduction in AChE (1.35% of control in month of June) and cytochrome oxidase (3.71% of control in the month of July) activity were noted in the cercaria exposed to 60% of 4 h LC50 of azadirachtin and allicin, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Biological control of Fasciola gigantica with Echinostoma revolutum.

    PubMed

    Suhardono; Roberts, J A; Copeman, D B

    2006-08-31

    A field trial was carried out in West Java to investigate the potential for control of fasciolosis of antagonism between larvae of Fasciola gigantica and Echinostoma revolutum in Lymnaea rubiginosa. The trial was undertaken in 26 farmers' irrigated rice fields, each chosen because it was adjacent to a cattle pen the effluent from which flowed into or was used as fertiliser in the rice field. Fourteen of the fields chosen at random were retained as controls and received no treatment while in 12, faeces from 5 to 15 ducks containing eggs of E. revolutum were introduced to the rice from a duck pen located over the effluent drain from the cattle pen before it emptied into the adjacent rice field, or at the site bovine faeces was added to the field as fertiliser. After harvest significantly fewer L. rubiginosa were found infected with F. gigantica in fields where duck and cattle dung entered the field together than in control fields, supporting a conclusion that this method of biological control would reduce the infectivity of rice fields fertilised with bovine dung (which are those with the highest potential for being a source of infection with F. gigantica). Positive features of using dung from ducks infected with E. revolutum to control F. gigantica are the minimum additional work and disruption to existing farming practices required to implement the scheme, the common natural infection with E. revolutum in village ducks, and effectiveness of dung from 5 to 15 ducks, a number commonly kept by farmers.

  19. Ecological studies on Al-Khadoud Spring, Al-Hassa, Saudi Arabia.

    PubMed

    Al-Kahtani, Mohammed A; Youssef, Ashraf M; Fathi, Adel A

    2007-11-15

    Al-Khadoud spring is one of the most important water resources in Al-Hassa Governorate, Saudi Arabia. However, much of its biotic information is still unknown. This study presented preliminary ecological information of this aquatic body. Regarding to macrophytes, a total of eight species were observed along the study sites. These species include two submerged aquatic plants (Potamogeton pectinatus L. and Ceratophyllum demersum L.). The common distributed species are Phragmites australis (Cav.) Trimex Steud and Cyperus rotundus (L.). On the other hand, a total of 20 algal genera were recorded with 7 genera of Chlorophyceae, 8 of Bacillariophyceae, 4 of Cyanophyceae and one of Euglenophyceae. The common phytoplankton occurred in all three investigated sites were Chlorella vulgaris, Mougeotia sp., Oscillatoria sp. and Actinastrum sp. Regarding to the biotic fauna, different forms of unicellular zooplankton such as Paramecium and Amoeba were recorded. Invertebrates such as freshwater insects and some freshwater snails were documented in the study sites including Melanodies tuberculata, Melanopsis praemorsa and Lymnaea auricularia. As regard to vertebrates, one species of fish, Aphanius dispar, dominate the spring basin and its extended channels.

  20. Phospholipase A2 – nexus of aging, oxidative stress, neuronal excitability, and functional decline of the aging nervous system? Insights from a snail model system of neuronal aging and age-associated memory impairment

    PubMed Central

    Hermann, Petra M.; Watson, Shawn N.; Wildering, Willem C.

    2014-01-01

    The aging brain undergoes a range of changes varying from subtle structural and physiological changes causing only minor functional decline under healthy normal aging conditions, to severe cognitive or neurological impairment associated with extensive loss of neurons and circuits due to age-associated neurodegenerative disease conditions. Understanding how biological aging processes affect the brain and how they contribute to the onset and progress of age-associated neurodegenerative diseases is a core research goal in contemporary neuroscience. This review focuses on the idea that changes in intrinsic neuronal electrical excitability associated with (per)oxidation of membrane lipids and activation of phospholipase A2 (PLA2) enzymes are an important mechanism of learning and memory failure under normal aging conditions. Specifically, in the context of this special issue on the biology of cognitive aging we portray the opportunities offered by the identifiable neurons and behaviorally characterized neural circuits of the freshwater snail Lymnaea stagnalis in neuronal aging research and recapitulate recent insights indicating a key role of lipid peroxidation-induced PLA2 as instruments of aging, oxidative stress and inflammation in age-associated neuronal and memory impairment in this model system. The findings are discussed in view of accumulating evidence suggesting involvement of analogous mechanisms in the etiology of age-associated dysfunction and disease of the human and mammalian brain. PMID:25538730

  1. Mercury net methylation in five tropical flood plain regions of Brazil: high in the root zone of floating macrophyte mats but low in surface sediments and flooded soils.

    PubMed

    Guimarães, J R; Meili, M; Hylander, L D; de Castro e Silva, E; Roulet, M; Mauro, J B; de Lemos, R

    2000-10-16

    In aquatic systems, bottom sediments have often been considered as the main methylmercury (MeHg) production site. In tropical floodplain areas, however, floating meadows and flooded forests extend over large areas and can be important Hg methylating sites. We present here a cross-system comparison of the Hg net methylation capacity in surface sediments, flooded soils and roots of floating aquatic macrophytes, assayed by in situ incubation with 203Hg and extraction of formed Me203 Hg by acid leaching and toluene. The presence of mono-MeHg was confirmed by thin layer chromatography and other techniques. Study areas included floodplain lakes in the Amazon basin (Tapajós, Negro and Amazon rivers), the Pantanal floodplain (Paraguay river basin), freshwater coastal lagoons in Rio de Janeiro and oxbow lakes in the Mogi-Guaçú river, São Paulo state. Different Hg levels were added in assays performed in 1994-1998, but great care was taken to standardise all other test parameters, to allow data comparisons. Net MeHg production was one order of magnitude higher (mean 13.8%, range 0.28-35) in the living or decomposing roots of floating or rooted macrophyte mats (Eichhornia azurea, E. crassipes, Paspalum sp., Eleocharis sellowiana, Salvinia sp., S. rotundifolia and Scirpus cubensis) than in the surface layer of underlying lake sediments (mean 0.6%, range 0.022-2.5). Methylation in flooded soils presented a wide range and was in some cases similar to the one found in macrophyte roots but usually much lower. In a Tapajós floodplain lake, natural concentrations of MeHg in soil and sediment cores taken along a lake-forest transect agreed well with data on net methylation potentials in the same samples. E. azurea, E. crassipes and Salvinia presented the highest methylation potentials, up to 113 times higher than in sediments. Methylation in E. azurea from six lakes of the Paraguay and Cuiabá rivers, high Pantanal, was determined in the 1998 dry and wet seasons and ranged from

  2. [Acute encephalopathy caused by cyanogenic fungi in 2004, and magic mushroom regulation in Japan].

    PubMed

    Gonmori, Kunio; Yokoyama, Kazumasa

    2009-03-01

    , Psilocybe cubensis, Psilocybe fasciata, Psilocybe lonchophorus, Psilocybe subaeruginascens, Psilocybe subcaerulipes, Psilocybe subcubensis, Psilocybe tampanensis, and Psilocybe venenata.

  3. Timed and targeted differential regulation of nitric oxide synthase (NOS) and anti-NOS genes by reward conditioning leading to long-term memory formation.

    PubMed

    Korneev, Sergei A; Straub, Volko; Kemenes, Ildikó; Korneeva, Elena I; Ott, Swidbert R; Benjamin, Paul R; O'Shea, Michael

    2005-02-02

    In a number of neuronal models of learning, signaling by the neurotransmitter nitric oxide (NO), synthesized by the enzyme neuronal NO synthase (nNOS), is essential for the formation of long-term memory (LTM). Using the molluscan model system Lymnaea, we investigate here whether LTM formation is associated with specific changes in the activity of members of the NOS gene family: Lym-nNOS1, Lym-nNOS2, and the antisense RNA-producing pseudogene (anti-NOS). We show that expression of the Lym-nNOS1 gene is transiently upregulated in cerebral ganglia after conditioning. The activation of the gene is precisely timed and occurs at the end of a critical period during which NO is required for memory consolidation. Moreover, we demonstrate that this induction of the Lym-nNOS1 gene is targeted to an identified modulatory neuron called the cerebral giant cell (CGC). This neuron gates the conditioned feeding response and is an essential part of the neural network involved in LTM formation. We also show that the expression of the anti-NOS gene, which functions as a negative regulator of nNOS expression, is downregulated in the CGC by training at 4 h after conditioning, during the critical period of NO requirement. This appears to be the first report of the timed and targeted differential regulation of the activity of a group of related genes involved in the production of a neurotransmitter that is necessary for learning, measured in an identified neuron of known function. We also provide the first example of the behavioral regulation of a pseudogene.

  4. Spider acetylcholine binding proteins: An alternative model to study the interaction between insect nAChRs and neonicotinoids.

    PubMed

    Bao, Haibo; Meng, Xiangkun; Liu, Zewen

    2017-10-06

    Acetylcholine binding proteins (AChBPs) are homologs of extracellular domains of nicotinic acetylcholine receptors (nAChRs) and serve as models for studies on nAChRs. Particularly, studies on invertebrate nAChRs that are limited due to difficulties in their heterologous expression have benefitted from the discovery of AChBPs. Thus far, AChBPs have been characterized only in aquatic mollusks, which have shown low sensitivity to neonicotinoids, the insecticides targeting insect nAChRs. However, AChBPs were also found in spiders based on the sequence and tissue expression analysis. Here, we report five AChBP subunits in Pardosa pseudoannulata, a predator enemy against rice insect pests. Spider AChBP subunits shared higher sequence similarities with nAChR subunits of both insects and mammals compared with mollusk AChBP subunits. The AChBP1 subunit of P. pseudoannulata (Pp-AChBP) was then expressed in Sf9 cells. The Ls-AChBP from Lymnaea stagnalis was also expressed for comparison. In both AChBPs, one ligand site per subunit was present at each interface between two adjacent subunits. Neonicotinoids had higher affinities (7.9-18.4 times based on Kd or Ki values) for Pp-AChBP than for Ls-AChBP, although epibatidine and α-bungarotoxin showed higher affinities for Ls-AChBP. These results indicate that spider AChBP could be used as an alternative model to study the interaction between insect nAChRs and neonicotinoids. Copyright © 2017. Published by Elsevier Ltd.

  5. Structural mechanisms for α-conotoxin activity at the human α3β4 nicotinic acetylcholine receptor

    PubMed Central

    Abraham, Nikita; Healy, Michael; Ragnarsson, Lotten; Brust, Andreas; Alewood, Paul F.; Lewis, Richard J.

    2017-01-01

    Nicotinic acetylcholine receptors (nAChR) are therapeutic targets for a range of human diseases. α-Conotoxins are naturally occurring peptide antagonists of nAChRs that have been used as pharmacological probes and investigated as drug leads for nAChR related disorders. However, α-conotoxin interactions have been mostly characterised at the α7 and α3β2 nAChRs, with interactions at other subtypes poorly understood. This study provides novel structural insights into the molecular basis for α-conotoxin activity at α3β4 nAChR, a therapeutic target where subtype specific antagonists have potential to treat nicotine addiction and lung cancer. A co-crystal structure of α-conotoxin LsIA with Lymnaea stagnalis acetylcholine binding protein guided the design and functional characterisations of LsIA analogues that identified the minimum pharmacophore regulating α3β4 antagonism. Interactions of the LsIA R10F with β4 K57 and the conserved –NN– α-conotoxin motif with β4 I77 and I109 conferred α3β4 activity to the otherwise inactive LsIA. Using these structural insights, we designed LsIA analogues with α3β4 activity. This new understanding of the structural basis of protein-protein interactions between α-conotoxins and α3β4 may help rationally guide the development of α3β4 selective antagonists with therapeutic potential. PMID:28361878

  6. Influence of hardness on the bioavailability of silver to a freshwater snail after waterborne exposure to silver nitrate and silver nanoparticles

    USGS Publications Warehouse

    Stoiber, Tasha L.; Croteau, Marie-Noele; Romer, Isabella; Tejamaya, Mila; Lead, Jamie R.; Luoma, Samuel N.

    2015-01-01

    The release of Ag nanoparticles (AgNPs) into the aquatic environment is likely, but the influence of water chemistry on their impacts and fate remains unclear. Here, we characterize the bioavailability of Ag from AgNO3 and from AgNPs capped with polyvinylpyrrolidone (PVP AgNP) and thiolated polyethylene glycol (PEG AgNP) in the freshwater snail, Lymnaea stagnalis, after short waterborne exposures. Results showed that water hardness, AgNP capping agents, and metal speciation affected the uptake rate of Ag from AgNPs. Comparison of the results from organisms of similar weight showed that water hardness affected the uptake of Ag from AgNPs, but not that from AgNO3. Transformation (dissolution and aggregation) of the AgNPs was also influenced by water hardness and the capping agent. Bioavailability of Ag from AgNPs was, in turn, correlated to these physical changes. Water hardness increased the aggregation of AgNPs, especially for PEG AgNPs, reducing the bioavailability of Ag from PEG AgNPs to a greater degree than from PVP AgNPs. Higher dissolved Ag concentrations were measured for the PVP AgNPs (15%) compared to PEG AgNPs (3%) in moderately hard water, enhancing Ag bioavailability of the former. Multiple drivers of bioavailability yielded differences in Ag influx between very hard and deionized water where the uptake rate constants (kuw, l g-1 d-1 ± SE) varied from 3.1 ± 0.7 to 0.2 ± 0.01 for PEG AgNPs and from 2.3 ± 0.02 to 1.3 ± 0.01 for PVP AgNPs. Modeling bioavailability of Ag from NPs revealed that Ag influx into L. stagnalis comprised uptake from the NPs themselves and from newly dissolved Ag.

  7. A natural focus of the blood fluke Orientobilharzia turkestanica (Skrjabin, 1913) (Trematoda: Schistosomatidae) in red deer (Cervus elaphus) in Hungary.

    PubMed

    Majoros, Gábor; Dán, Adám; Erdélyi, Károly

    2010-06-24

    The large American liver fluke, Fascioloides magna - introduced to Europe before 1875 - was the first non-indigenous trematode to be detected in Hungarian cervids in 1995. As the most precious deer population became infected in the Gemenc game reserve a study has been launched to assess the extent and the effect of F. magna infections and to examine the options for the treatment of infected deer populations. Livers of red deer shot during regular hunting were submitted for the survey and were investigated by necropsy for the presence of F. magna and other liver dwelling trematodes. Recovered parasites were counted, sorted and stored in 70% ethanol. Unexpectedly, blood flukes were found in liver blood vessels at necropsy. They were identified as Orientobilharzia turkestanica (Skrjabin, 1913) by their morphological features as well as by molecular methods. This parasite is widespread in the middle belt of Asia from Korea to the eastern part of Turkey and infects mainly bovids. It was never found in red deer until now and this is the first report of its occurrence in Hungary and Europe. A subsequent search for the local intermediate host of O. turkestanica in the Gemenc area identified only the pulmonate snail Radix auricularia (Linnaeus, 1758) [syn: Lymnaea auricularia] as a vector capable of producing cercariae of this trematode. Cercariae of O. turkestanica were examined morphologically and were confirmed to be the larvae of this trematode by PCR. O. turkestanica appears to be fairly common in red deer of the Gemenc area. No clinical or pathological effect of the infection could be identified in this study. A form of cercarial dermatitis locally called "water mange" was formerly attributed to the larvae of avian shistosomes. It regularly occurred among fishermen fishing in shallow ponds remaining after floods along the Danube in the Gemenc area. This isolated habitat of O. turkestanica presents an exceptional opportunity to study epidemical situations of typical

  8. Determining metal assimilation efficiency in aquatic invertebrates using enriched stable metal isotope tracers

    USGS Publications Warehouse

    Croteau, M.-N.; Luoma, S.N.; Pellet, B.

    2007-01-01

    We employ a novel approach that combines pulse-chase feeding and multi-labelled stable isotopes to determine gut passage time (GPT), gut retention time (GRT), food ingestion rate (IR) and assimilation efficiency (AE) of three trace elements for a freshwater gastropod. Lettuce isotopically enriched in 53Cr, 65Cu and 106Cd was fed for 2 h to Lymnaea stagnalis. The release of tracers in feces and water was monitored for 48 h, during which unlabelled lettuce was provided ad libidum. The first defecation of 53Cr occurred after 5 h of depuration (GPT), whereas 90% of the ingested 53Cr was recovered in the feces after 22.5 h of depuration (GRT). 53Chromium was not significantly accumulated in the soft tissues upon exposure. In contrast, 65Cu and 106Cd assimilation was detectable for most experimental snails, i.e., 65/63Cu and 106/114Cd ratios in exposed snails were higher than those for controls. Food IR during the labelled feeding phase was 0.16 ?? 0.07 g g-1 d-1. IR was inferred from the amount of 53Cr egested in the feces during depuration and the concentration of 53Cr in the labelled lettuce. Assimilation efficiencies (??95% CI) determined using mass balance calculations were 84 ?? 4% for Cu and 85 ?? 3% for Cd. The ratio method yields similar AE estimates. Expanding the application of this novel stable isotope tracer technique to other metals in a wide variety of species will provide unique opportunities to evaluate the interplay between digestive processes and dietary influx of metals. Understanding the biological processes that modulate dietborne metal uptake is crucial to assess the toxicity of dietborne metals. ?? 2007 Elsevier B.V. All rights reserved.

  9. Cloning and characterization of a novel G protein beta-subunit of pearl oyster (Pinctada fucata), and its interaction sites with calmodulin.

    PubMed

    Chen, Lei; Xie, Liping; Xiong, Xunhao; Dai, Yiping; Fan, Weimin; Zhang, Rongqing

    2005-10-01

    A cDNA clone encoding a novel G protein beta subunit of beta1 subclass, pfGbeta1 was isolated from the pearl oyster (Pinctada fucata). The deduced amino acid sequence of pfGbeta1 (341 amino acids) shares high homology to northern European squid (Loligo pealei) and great pond snail (Lymnaea stagnalis) pfGbeta1, while it has diverged from bovine (Bos taurus) and human. The well-conserved amino acid domains in G protein beta subunit, seven WD repeats, were founded in the deduced amino acid sequence. Alignment analysis showed that the beginning amino acid residues in variable fragment of the seventh WD motif are different from any other Gbeta. The prediction of 3D structure of pfGbeta showed that pfGbeta belongs to beta-propeller family proteins whose members contain 4-8 antiparallel beta-sheets resembling the blades of a propeller. In situ hybridization and Northern blotting analysis revealed that the pfGbeta mRNA hybridization signals were widely expressed in various tissues except muscle, with abundantly in epithelia of gill, gonad and outer fold of mantle. We also investigated the interactions between Gbetagamma and calmodulin (CaM), and specific amino acid residues that may be critical for the binding of Gbetagamma to CaM were also identified. Furthermore, the functional studies of the interaction showed that the binding of CaM and Gbetagamma increases the alkaline phosphatase (ALP) activity, an indicator for mineralization in MC3T3-E1 cells. The ALP activity of the mutants of pfGbetagamma that impaired the interactions of Gbetagamma with CaM is higher than the Control group; however, it is lower than the WTC group. Together, these results suggest that the Gbetagamma might interact with CaM and point to the important physiological function in modulating cellular functions.

  10. Dynamics of Fasciola hepatica transmission in the Andean Patagonian valleys, Argentina.

    PubMed

    Kleiman, Florencia; Pietrokovsky, Silvia; Prepelitchi, Lucila; Carbajo, Aníbal E; Wisnivesky-Colli, Cristina

    2007-04-30

    We described the transmission dynamics of Fasciola hepatica at its southern distribution range. Studies of prevalence and egg output in cattle and population dynamics and infection in snails were performed in a farm in the Andean Patagonian valleys, Argentina, between December 1998 and February 2002. Snail surveys were conducted from spring to autumn. Infection was diagnosed coprologically in the whole herd at the beginning and end of the study, and in a cohort of heifers at the beginning and end of 2001. A twice-a-year anthelmintic treatment was implemented in 1999. The relationship of the variables mentioned above with temperature and rainfall was determined. Lymnaea viatrix showed a life-span of about 15 months and an annual pattern of population dynamics. Specimens were frequently found in temporary environments and lagoons, and rarely in streams. Snail abundance and soil-water availability were directly related in temporary environments and inversely related in lagoons. Overall prevalence in L. viatrix was 0.67% (range: 0.9-14%) and infection was detected in summer and autumn. At the beginning of the study, calves were the least infected age group (15%). Prevalences and median egg counts in grazing animals were similar at the beginning (heifers: 81%, 3.3 epg; cows: 60%, 1.3 epg) and end of the study (heifers and cows: around 51%, 1 epg). Likewise, the prevalence in the cohort of heifers remained similar (around 40%) between surveys. Transmission to cattle was highly effective despite of the short activity period and the low infection rate of snails, and the regular anthelminthic treatment. There would be two seasonal transmission peaks, one in summer-autumn, when infected snails were present, and the other in early spring due to overwintering metacercariae. Some recommendations based on the climatic conditions of the region are provided to minimize snail infection and ultimately to reduce the incidence of fasciolosis in cattle.

  11. Isotopically modified silver nanoparticles to assess nanosilver bioavailability and toxicity at environmentally relevant exposures

    USGS Publications Warehouse

    Croteau, Marie-Noële; Dybowska, Agnieszka D.; Luoma, Samuel N.; Misra, Superb K.; Valsami-Jones, Eugenia

    2014-01-01

    A major challenge in understanding the environmental implications of nanotechnology lies in studying nanoparticle uptake in organisms at environmentally realistic exposure concentrations. Typically, high exposure concentrations are needed to trigger measurable effects and to detect accumulation above background. But application of tracer techniques can overcome these limitations. Here we synthesised, for the first time, citrate-coated Ag nanoparticles using Ag that was 99.7 % 109Ag. In addition to conducting reactivity and dissolution studies, we assessed the bioavailability and toxicity of these isotopically modified Ag nanoparticles (109Ag NPs) to a freshwater snail under conditions typical of nature. We showed that accumulation of 109Ag from 109Ag NPs is detectable in the tissues of Lymnaea stagnalis after 24-h exposure to aqueous concentrations as low as 6 ng L–1 as well as after 3 h of dietary exposure to concentrations as low as 0.07 μg g–1. Silver uptake from unlabelled Ag NPs would not have been detected under similar exposure conditions. Uptake rates of 109Ag from 109Ag NPs mixed with food or dispersed in water were largely linear over a wide range of concentrations. Particle dissolution was most important at low waterborne concentrations. We estimated that 70 % of the bioaccumulated 109Ag concentration in L. stagnalis at exposures –1 originated from the newly solubilised Ag. Above this concentration, we predicted that 80 % of the bioaccumulated 109Ag concentration originated from the 109Ag NPs. It was not clear if agglomeration had a major influence on uptake rates.