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Sample records for lymnaea cubensis molusco

  1. 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

  2. Complete mitochondrial genome of Pseudoperonospora cubensis.

    PubMed

    Lu, Wei-Jia; Hu, Wen-Guo; Wang, Guang-Peng

    2016-09-01

    Pseudoperonospora cubensis is a species of water mould known for causing downy mildew on cucurbits. 454 GS FLX Titanium sequencing data was used to obtain its complete mitochondrial genome (38 553 bp). The mitogenome contains 60 genes, including two ribosomal RNA, 25 transfer RNA, 15 ribosomal proteins, five open reading frames (ORFs). The rps3 and rpl16 overlapped each other by 14 bp. The gene order and composition of P. cubensis was similar to that of most other oomycetes, and its GC content was 22.4%. It is the first report of the complete mitochondrial genome in the genus Pseudoperonospora. Phylogeny analysis indicates that P. cubensis has a close genetic relationship with genus Phytophthora. PMID:26186306

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  4. Resistance in Cucumis melo germplasm to Pseudoperonospora cubensis pathotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Cucumis melo-Pseudoperonospora cubensis host-pathogen interaction is characterized by large variation in specificity. This report summarizes results obtained by laboratory screening of 52 C. melo accessions by 8 isolates of P. cubensis. The isolates represent 8 different pathotypes with low, m...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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

    Savory, Elizabeth A; Adhikari, Bishwo N; 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. MOLECULAR ANALYSIS OF NEW SOURCES OF RESISTANCE TO Pseudoperonospora cubensis (Berk. et Curt.) Rostovzev in CUCUMBER.

    PubMed

    Szczechura, W; Staniaszek, M; Klosinska, U; Kozik, E U

    2015-10-01

    Downy mildew of cucumber (Cucumis sativus L.), caused by Pseudoperonospora cubensis (Berk. et Curt.) Rostovzev, is one of the most important foliar diseases of cucurbit crops. Two parental lines resistant PI 197085, susceptible PI 175695 and their F2 generation were used in our study. Inheritance of resistance to Pseudoperonospora cubensis in PI 197085 was quantitative. JoiMap 4.1 and MapQTL 6.0 software was used for a linkage groups construction and QTL mapping. Three QTL were detected: DM1, DM2, DM3. The loci were mapped on chromosome 5 of cucumber genome. Molecular analysis confirmed results of classical quantitative genetics indicating that resistance to Pseudoperonospora cubensis in PI 197085 is polygenic trait. PMID:27169228

  8. Identification and characterization of cucumber microRNAs in response to Pseudoperonospora cubensis infection.

    PubMed

    Jin, Weibo; Wu, Fangli

    2015-09-15

    MicroRNAs (miRNAs) regulate the expression of genes related to several stress responses, including fungal infection, in plants. However, the miRNA-mediated gene regulatory networks in cucumbers that respond to Pseudoperonospora cubensis stress remain unexplored. In this study, the miRNA expression patterns in response to P. cubensis stress in cucumbers were investigated through high-throughput sequencing. A total of 123 known miRNAs and 4 novel miRNAs were identified, and their corresponding expressions were detected in mock- and P. cubensis-inoculated leaves. Three novel and 39 known miRNAs were found to be differentially expressed in P. cubensis-infected leaves. The results of 5'-RLM-RACE confirmed that miR164b, miR156h, miR171e, miR160b, and miR159f targeted No Apical Meristem domain protein, squamosa promoter binding protein-like class transcription factor, GRAS family transcription factor, Auxin response factor ARF16, and a conserved gene of unknown function, respectively. The expression patterns of these miRNAs were also determined through quantitative reverse transcription polymerase chain reaction (qRT-PCR). All of these miRNAs, except for miR156h, can respond to P. cubensis infection in cucumber leaves. In addition, the results of qRT-PCR revealed that the targets negatively correlated with their corresponding miRNAs (miR164b, miR171e, miR160b, and miR159f). PMID:26071186

  9. 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

  10. Regional and Temporal Population Structure of Pseudoperonospora cubensis in Michigan and Ontario.

    PubMed

    Naegele, R P; Quesada-Ocampo, L M; Kurjan, J D; Saude, C; Hausbeck, M K

    2016-04-01

    Cucurbit downy mildew (CDM), caused by the oomycete pathogen Pseudoperonospora cubensis, is a devastating disease that affects cucurbit species worldwide. This obligate, wind-dispersed pathogen does not overwinter in Michigan or other northern regions and new isolates can enter the state throughout the growing season. To evaluate the regional and temporal population structure of P. cubensis, sporangia from CDM lesions were collected from cucurbit foliage grown in Michigan and Ontario field locations in 2011. Population structure and genetic diversity were assessed in 257 isolates using nine simple sequence repeat markers. Genetic diversity was high for isolates from Michigan and Canada (0.6627 and 0.6131, respectively). Five genetic clusters were detected and changes in population structure varied by site and sampling date within a growing season. The Michigan and Canada populations were significantly differentiated, and a unique genetic cluster was detected in Michigan. PMID:26735060

  11. 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…

  12. Comparing RNA-seq and GBS to identify SNPs useful for determining population structure in obligate biotrophic pathogens Pseudoperonospora cubensis and P. humuli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  14. 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. PMID:26012858

  15. Morphological and physiological characteristics of dermal photoreceptors in Lymnaea stagnalis

    PubMed Central

    Takigami, Satoshi; Sunada, Hiroshi; Horikoshi, Tetsuro; Sakakibara, Manabu

    2014-01-01

    Dermal photoreceptors located in the mantle of Lymnaea stagnalis were histologically and physiologically characterized. Our previous study demonstrated that the shadow response from dermal photoreceptors induces the whole-body withdrawal response. Through the interneuron, RPeD11, we detected that the light-off response indirectly originated from a dermal photoreceptor. Previous observations, based on behavioral pharmacology, revealed that cyclic guanosine monophosphate acts as a second messenger in the dermal photoreceptor. Furthermore, gastropods possess dermal photoreceptors containing rhodopsin, as a photopigment, and another photo-sensitive protein, arrestin, responsible for terminating the light response. Thus, we chose three antibodies, anti-cGMP, anti-rhodopsin, and anti-β-arrestin, to identify the dermal photoreceptor molecules in Lymnaea mantle. Extracellular recording, using a suction electrode on the mantle, revealed a light off-response from the right parietal nerve. Overlapping structures, positive against each of the antibodies, were also observed. Numerous round, granular particles of 3–47 μm in diameter with one nucleus were distributed around pneumostome and/or inside the mantle. The cells surrounding the pneumostome area, located 10 μm beneath the surface, tended to have smaller cell soma ranging from 3 to 25 μm in diameter, while cells located in other areas were distributed uniformly inside the mantle, with a larger diameter ranging from 12 to 47 μm. The histological examination using back-filing Lucifer Yellow staining of the right parietal nerve with the three dermal photoreceptor antibodies confirmed that these overlapping-stained structures were dermal photoreceptors in Lymnaea. PMID:27493502

  16. 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

  17. 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. PMID:26002291

  18. 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.

  19. 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

  20. Alternative splicing of a multi-drug transporter from Pseudoperonospora cubensis generates an RXLR effector protein that elicits a rapid cell death.

    PubMed

    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

  1. 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. PMID:25549212

  2. 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. PMID:23431525

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

    PubMed Central

    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. PMID:25549212

  4. 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

  5. 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

  6. 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. PMID:20038665

  7. 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

  8. 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

  9. De Novo Sequencing and Transcriptome Analysis of the Central Nervous System of Mollusc Lymnaea stagnalis by Deep RNA Sequencing

    PubMed Central

    Sadamoto, Hisayo; Takahashi, Hironobu; Okada, Taketo; Kenmoku, Hiromichi; Toyota, Masao; Asakawa, Yoshinori

    2012-01-01

    The pond snail Lymnaea stagnalis is among several mollusc species that have been well investigated due to the simplicity of their nervous systems and large identifiable neurons. Nonetheless, despite the continued attention given to the physiological characteristics of its nervous system, the genetic information of the Lymnaea central nervous system (CNS) has not yet been fully explored. The absence of genetic information is a large disadvantage for transcriptome sequencing because it makes transcriptome assembly difficult. We here performed transcriptome sequencing for Lymnaea CNS using an Illumina Genome Analyzer IIx platform and obtained 81.9 M of 100 base pair (bp) single end reads. For de novo assembly, five programs were used: ABySS, Velvet, OASES, Trinity and Rnnotator. Based on a comparison of the assemblies, we chose the Rnnotator dataset for the following blast searches and gene ontology analyses. The present dataset, 116,355 contigs of Lymnaea transcriptome shotgun assembly (TSA), contained longer sequences and was much larger compared to the previously reported Lymnaea expression sequence tag (EST) established by classical Sanger sequencing. The TSA sequences were subjected to blast analyses against several protein databases and Aplysia EST data. The results demonstrated that about 20,000 sequences had significant similarity to the reported sequences using a cutoff value of 1e-6, and showed the lack of molluscan sequences in the public databases. The richness of the present TSA data allowed us to identify a large number of new transcripts in Lymnaea and molluscan species. PMID:22870333

  10. 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.

  11. 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. PMID:2626571

  12. 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. PMID:22549769

  13. 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

  14. The influence of pretreatment methods on saccharification of sugarcane bagasse by an enzyme extract from Chrysoporthe cubensis and commercial cocktails: A comparative study.

    PubMed

    Maitan-Alfenas, Gabriela Piccolo; Visser, Evan Michael; Alfenas, Rafael Ferreira; Nogueira, Bráulio Ris G; de Campos, Guilherme Galvão; Milagres, Adriane Ferreira; de Vries, Ronald P; Guimarães, Valéria Monteze

    2015-09-01

    Biomass enzymatic hydrolysis depends on the pretreatment methods employed, the composition of initial feedstock and the enzyme cocktail used to release sugars for subsequent fermentation into ethanol. In this study, sugarcane bagasse was pretreated with 1% H2SO4 and 1% NaOH and the biomass saccharification was performed with 8% solids loading using 10 FPase units/g of bagasse of the enzymatic extract from Chrysoporthe cubensis and three commercial cocktails for a comparative study. Overall, the best glucose and xylose release was obtained from alkaline pretreated sugarcane bagasse. The C. cubensis extract promoted higher release of glucose (5.32 g/L) and xylose (9.00 g/L) than the commercial mixtures. Moreover, the C. cubensis extract presented high specific enzyme activities when compared to commercial cocktails mainly concerning to endoglucanase (331.84 U/mg of protein), β-glucosidase (29.48 U/mg of protein), β-xylosidase (2.95 U/mg of protein), pectinase (127.46 U/mg of protein) and laccase (2.49 U/mg of protein). PMID:26094192

  15. 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. PMID:26599440

  16. 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

  17. 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

    2016-01-01

    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. PMID:27394893

  18. [Predation of Lymnaea (Galba) truncatula Müller by Zonitoides nitidus Müller (Mollusca Gastropoda Pulmonata) (author's transl)].

    PubMed

    Rondelaud, D

    1975-01-01

    Zonitoides nitidus is omnivorous with carnivorous tendancies: the presence of food coming from snails is required for growth of this predator. This snail is not selective for the choice of its preys. Zonitoides cannot be taken for an absolute predator for all growing periods of Lymnaea truncatula: eggs and large snails are not eaten. This species can be cannibal. PMID:1211765

  19. 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. PMID:19968555

  20. Do larvae of Trichobilharzia szidati and Echinostoma revolutum generate behavioral fever in Lymnaea stagnalis individuals?

    PubMed

    Zbikowska, Elzbieta

    2005-08-01

    The objective of this study was to determine whether individuals of Lymnaea stagnalis naturally parasitized with Trichobilharzia szidati and Echinostoma revolutum can generate the behavioral fever against larvae of those parasites. Thermal preferences of each snail were examined in an oblong thermal gradient during 48 h observation. Uninfected animals under study chose higher temperatures than those releasing cercariae of parasites. Infected snails kept in constant temperature lived shorter than uninfected ones. At high temperature, they released more cercariae per day than at low temperature. Temperature had a great influence on the longevity of emerged cercariae. The thermal behavior of infected snails is not a symptom of behavioral fever but probably can play a therapeutic role in the host. PMID:15952039

  1. The effect of digenea larvae on calcium content in the shells of Lymnaea stagnalis (L.) individuals.

    PubMed

    Zblkowska, Elzbieta

    2003-02-01

    The objective of this work was to examine the calcium concentration in the shells of naturally infected individuals of Lymnaea stagnalis. Calcium concentration in the water of lakes and in snail shells was examined by the EDTA method. Calcium concentration in the shells of infected snails was found to be higher than that in the shells of uninfected ones only in the lake with the lowest calcium concentration in water. However, this difference is not evidence of hypercalcification of snail shells caused by trematode larvae but suggests that the limited calcium concentration in the environment can be a very good factor for studying snail shell calcification under natural conditions. Moreover, small adult snails from 2 lakes had more calcium in their shells than did large ones. Different reproductive rates of different-sized snails could be the cause of this phenomenon. PMID:12659306

  2. 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. PMID:27358197

  3. 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.

  4. A Sodium Leak Current Regulates Pacemaker Activity of Adult Central Pattern Generator Neurons in Lymnaea Stagnalis

    PubMed Central

    Lu, Tom Z.; Feng, Zhong-Ping

    2011-01-01

    The resting membrane potential of the pacemaker neurons is one of the essential mechanisms underlying rhythm generation. In this study, we described the biophysical properties of an uncharacterized channel (U-type channel) and investigated the role of the channel in the rhythmic activity of a respiratory pacemaker neuron and the respiratory behaviour in adult freshwater snail Lymnaea stagnalis. Our results show that the channel conducts an inward leak current carried by Na+ (ILeak-Na). The ILeak-Na contributed to the resting membrane potential and was required for maintaining rhythmic action potential bursting activity of the identified pacemaker RPeD1 neurons. Partial knockdown of the U-type channel suppressed the aerial respiratory behaviour of the adult snail in vivo. These findings identified the Na+ leak conductance via the U-type channel, likely a NALCN-like channel, as one of the fundamental mechanisms regulating rhythm activity of pacemaker neurons and respiratory behaviour in adult animals. PMID:21526173

  5. 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. PMID:25617463

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

    PubMed Central

    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. PMID:27493506

  7. 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

  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. 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. PMID:26734552

  10. An increase in insulin is important for the acquisition conditioned taste aversion in Lymnaea.

    PubMed

    Mita, Koichi; Yamagishi, Miki; Fujito, Yutaka; Lukowiak, Ken; Ito, Etsuro

    2014-12-01

    Conditioned taste aversion (CTA) in Lymnaea is brought about by pairing a sucrose solution (the conditioned stimulus, CS) with an electric shock (the unconditioned stimulus, US). Following repeated CS-US pairings, CTA occurs and it is consolidated into long-term memory (LTM). The best CTA is achieved, if snails are food-deprived for 1 day before training commences. With a longer period of food deprivation (5 days), learning and memory formation does not occur. It has been hypothesized that the levels of insulin in the central nervous system (CNS) are very important for CTA to occur. To test his hypothesis, we injected insulin directly into 5-day food-deprived snails. The injection of insulin, as expected, resulted in a decrease in hemolymph glucose concentration. Consistent with our hypothesis with insulin injection, learning and memory formation of CTA occurred. That is, the 'insulin spike' is more important than an increase in hemolymph glucose concentration for CTA-LTM. If we injected an insulin receptor antibody into the snails before the insulin injection, learning was formed but memory formation was not, which is consistent with our previous study. Therefore, a rise in the insulin concentration (i.e., insulin spike) in the CNS is considered to be a key determining factor in the process of CTA-LTM. PMID:25451307

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

    PubMed

    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

  12. Environmental versus Anthropogenic Effects on Population Adaptive Divergence in the Freshwater Snail Lymnaea stagnalis

    PubMed Central

    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 QST -FST comparisons. Despite strong neutral differentiation (mean FST = 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. PMID:25207985

  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. PMID:24081640

  14. [Individual growth of Lymnaea stagnalis (Lymnaeidae, Gastropoda): II. Late postlarval ontogeny].

    PubMed

    Zotin, A A

    2009-01-01

    Our investigation on the growth of 14 individuals of the great pond snail Lymnaea stagnalis was performed in an aquatic culture at 18 degrees C beginning from the 10th week after hatching until death. It has been demonstrated that the increase in the mollusk mass follows an S-like curve during the whole studied period. Linear growth (conch height) follows a parabolic (convex) curve until the age of 39 weeks. Both weight and linear growth during studied period significantly approximate to the Bertalanffy equation, while the interrelation between mass and conch height corresponds to the allometric equation. The meanings of the coefficients of these equations do not differ significantly in different individuals. At the age of 38 to 39 weeks, all mollusks demonstrate breakage in the curve of linear growth, then followed with abrupt slowing of growth until stopping or even decreasing in size in some cases. Neither the Bertalanffy equation nor the allometric relation describe the linear growth of individuals with ages exceeding 39 weeks. PMID:20143629

  15. 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

  16. Factors affecting laboratory acclimatization of field collected Lymnaea (Bullastra) cumingiana Pfeiffer (Pulmonata: Lymnaeidae).

    PubMed

    Monzon, R B; Kitikoon, V

    1991-12-01

    Lymnaea (Bullastra) cumingiana, the newly discovered natural second intermediate host of Echinostoma malayanum in the Philippines, is a sensitive and delicate lymnaeid species which requires certain conditions for successful transport from the field and cultivation in the laboratory. Field collected specimens were found to be best transported in styrofoam containers lined with wet filter paper or containing natural substrate and vegetation instead of Sphagnum moss. The method is convenient and produces a survival rate of 73-86%. However, transport time is crucial and mortality increases the longer the snails are in transit. For optimal results in laboratory acclimatization, snails are best raised in wide-mouthed containers providing a large exposed water surface area. Adequate aeration is advised but vigorous bubbling of the water should be avoided. Water should be replaced with filtered dechlorinated water every 2 to 3 days, depending on water quality. A combination of fresh lettuce leaves and a few flakes of fish food was found to be ideal. Lastly, population density was the most significant factor affecting survival and so overcrowding should be avoided. PMID:1820655

  17. Operant Conditioning in Lymnaea: Evidence for Intermediate- and Long-term Memory

    PubMed Central

    Lukowiak, Ken; Adatia, Nimet; Krygier, Darin; Syed, Naweed

    2000-01-01

    Aerial respiration of the pond snail, Lymnaea stagnalis, can be operantly conditioned; however, the parameters necessary to produce long-term (LTM) or intermediate term memory (ITM) have not previously been investigated. We conducted training using procedures that varied in the duration of the training session, the number of training sessions per day or the amount of time between subsequent training sessions (SI). We found that by varying the duration and frequency of the training session learning could be differentially produced. Furthermore, the ability to form LTM was dependent not only on the duration of the training session was also the interval between training sessions, the SI. Thus it was possible to produce ITM, which persists for up to 3 hr, and not form LTM, which persists at least 18 hr. Learning, ITM, and LTM can be differentially produced by altering the SI, the duration of the training session, or the number of training sessions per day. These findings may allow us to begin to elucidate the underlying neural mechanisms of learning, ITM, and LTM. PMID:10837503

  18. 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.

  19. 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

  20. A Whole Mount In Situ Hybridization Method for the Gastropod Mollusc Lymnaea stagnalis.

    PubMed

    Jackson, Daniel J; Herlitze, Ines; Hohagen, Jennifer

    2016-01-01

    Whole mount in situ hybridization (WMISH) is a technique that allows for the spatial resolution of nucleic acid molecules (often mRNAs) within a 'whole mount' tissue preparation, or developmental stage (such as an embryo or larva) of interest. WMISH is extremely powerful because it can significantly contribute to the functional characterization of complex metazoan genomes, a challenge that is becoming more of a bottleneck with the deluge of next generation sequence data. Despite the conceptual simplicity of the technique much time is often needed to optimize the various parameters inherent to WMISH experiments for novel model systems; subtle differences in the cellular and biochemical properties between tissue types and developmental stages mean that a single WMISH method may not be appropriate for all situations. We have developed a set of WMISH methods for the re-emerging gastropod model Lymnaea stagnalis that generate consistent and clear WMISH signals for a range of genes, and across all developmental stages. These methods include the assignment of larvae of unknown chronological age to an ontogenetic window, the efficient removal of embryos and larvae from their egg capsules, the application of an appropriate Proteinase-K treatment for each ontogenetic window, and hybridization, post-hybridization and immunodetection steps. These methods provide a foundation from which the resulting signal for a given RNA transcript can be further refined with probe specific adjustments (primarily probe concentration and hybridization temperature). PMID:27023483

  1. Heat stress enhances LTM formation in Lymnaea: role of HSPs and DNA methylation.

    PubMed

    Sunada, Hiroshi; Riaz, Hamza; de Freitas, Emily; Lukowiak, Kai; Swinton, Cayley; Swinton, Erin; Protheroe, Amy; Shymansky, Tamila; Komatsuzaki, Yoshimasa; Lukowiak, Ken

    2016-05-01

    Environmentally relevant stressors alter the memory-forming process in Lymnaea following operant conditioning of aerial respiration. One such stressor is heat. Previously, we found that following a 1 h heat shock, long-term memory (LTM) formation was enhanced. We also had shown that the heat stressor activates at least two heat shock proteins (HSPs): HSP40 and HSP70. Here, we tested two hypotheses: (1) the production of HSPs is necessary for enhanced LTM formation; and (2) blocking DNA methylation prevents the heat stressor-induced enhancement of LTM formation. We show here that the enhancing effect of the heat stressor on LTM formation occurs even if snails experienced the stressor 3 days previously. We further show that a flavonoid, quercetin, which inhibits HSP activation, blocks the enhancing effect of the heat stressor on LTM formation. Finally, we show that injection of a DNA methylation blocker, 5-AZA, before snails experience the heat stressor prevents enhancement of memory formation. PMID:27208033

  2. Role for electrical synapses in shaping the output of coupled peptidergic neurons from Lymnaea.

    PubMed

    Beekharry, Christopher C; Zhu, Guan Z; Magoski, Neil S

    2015-04-01

    Electrically coupled neurons communicate through channel assemblies called gap junctions, which mediate the transfer of current from one cell to another. Electrical synapses ensure spike synchronization and reliable transmission, which influences bursting patterns and firing frequency. The present study concerns an electrically coupled two-neuron network in the gastropod mollusc, Lymnaea stagnalis. The neurons, designated Visceral Dorsal 1 (VD1) and Right Parietal Dorsal 2 (RPD2), are peptidergic, innervate aspects of the cardio-respiratory system, and show strong coupling, such that they fire synchronously. Using dual sharp-electrode current-clamp recording and morphological staining in isolated brain preparations, the hypothesis that the electrical synapse is necessary for accurate network output was tested. We found that both cells make extensive projections within and out of the brain, including across the visceral-parietal connective, which links VD1 and RPD2. Cutting this connective uncoupled the neurons and disrupted the firing rate and pattern of RPD2 more than VD1, consistent with VD1 being the master and RPD2 the follower. The electrical synapse was inhibited by select gap junction blockers, with niflumic acid and 5-nitro-2-(3-phenylpropylamino) benzoic acid decreasing the VD1→RPD2 and RPD2→VD1 coupling coefficients, whereas carbenoxolone, α-glycyrrhetinic acid, meclofenamic acid, and quinine were ineffective. There was little-to-no impact on VD1↔RPD2 firing synchrony or frequency when coupling was reduced pharmacologically. However, in the presence of gap junction blockers, suppressing the activity of VD1 by prolonged hyperpolarization revealed a distinct, low-frequency firing pattern in RPD2. This suggests that strong electrical coupling is key to maintaining a synchronous output and proper firing rate. PMID:25641041

  3. 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

  4. 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

  5. Immunotoxicity of surface waters contaminated by municipal effluents to the snail Lymnaea stagnalis.

    PubMed

    Gust, M; Fortier, M; Garric, J; Fournier, M; Gagné, F

    2013-01-15

    The immunotoxic effects of surface waters contaminated by a municipal effluent dispersion plume were examined in the snail Lymnaea stagnalis. Snails were exposed to surface waters where changes in hemocyte counts, viability, levels of reactive oxygen species (ROS), reduced thiols and phagocytic activity were tracked following exposure periods of 3h and 3 and 7d. Changes in mRNA expression of some genes in the hemocytes were also assessed after 7d of exposure, as follows: genes coding for catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GSR), selenium-dependent glutathione peroxidase (SeGPX), two isoforms of the nitric oxide synthetase (NOS1 and NOS2), molluscan defensive molecule (MDM), toll-like receptor 4 (TLR4), allograft inflammatory factor-1 (AIF), and heat-shock protein 70 (HSP70). At the sites closest to the discharge point, exposure led to impaired hemocyte viability and intracellular thiol levels and also an increase of hemocyte count, ROS levels and phagocytosis. Phagocytosis and ROS levels in hemocytes were correlated with heterotrophic bacterial counts in snails. We found four genes with increased mRNA expression as a response to exposure of municipal wastewaters: TLR4 (6-fold), HSP70 (2-fold), SeGPx (4-fold) and CAT (2-fold). Immunocompetence responses were analyzed by canonical analysis to seek out relationships with mRNA expression of the genes involved in stress, pattern recognition, cellular and humoral responses. The data revealed that genes involved in oxidative stress were strongly involved with immunocompetence and that the resulting immune responses were influenced both by the bacterial and pollutant loadings of the effluent. PMID:23021492

  6. 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. PMID:26340121

  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. PMID:26771541

  8. 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. PMID:26250985

  9. 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

  10. Chronic toxicity of tributyltin to development and reproduction of the European freshwater snail Lymnaea stagnalis (L.).

    PubMed

    Leung, Kenneth M Y; Grist, Eric P M; Morley, Neil J; Morritt, David; Crane, Mark

    2007-01-01

    Chronic toxicity, growth and reproduction were measured in the freshwater gastropod Lymnaea stagnalis exposed to waterborne bis(tri-n-butyltin) oxide (TBTO) over a range of four nominal concentrations (0-10microg TBTl(-1)). Egg development was completely inhibited at 10microg TBTl(-1), whilst abnormal embryonic development was observed at 1microg TBTl(-1). For the solvent control and the 0.01microg TBTl(-1)treatment group, normal development of L. stagnalis was observed. Survivorship of hatchlings was significantly reduced by TBT at 1microgl(-1) while inhibition of shell growth of L. stagnalis was also observed at this concentration. The data were used to determine intrinsic growth rates (r) using two theoretical approaches (the Euler-Lotka equation and a Leslie Matrix). Both approaches showed that survival, fecundity and population growth rate were reduced at 1microg TBTl(-1). Interestingly, at 0.01microg TBTl(-1) snails showed a higher fecundity and growth rate than in the solvent control. The TBT concentration at which the r would equal zero (ECr(0)) and the population NOEC (No Observed Effect Concentration) were estimated. The population NOEC was defined as either the lower 95% confidence or lower 95% pointwise percentile limit of the ECr(0). Values obtained using the two different approaches were similar and thus a geometric mean was calculated to obtain a final representative population NOEC value for L. stagnalis of 2745ng TBTl(-1). The present data together with chronic toxicity TBT data for freshwater organisms, obtained from peer-reviewed literature, were used to construct a species sensitivity distribution (SSD). A predicted no effect concentration was then derived from the SSD (hazardous concentration at 5%, i.e., HC5 or 95% protection level). This SSD was compared with the SSD derived from saltwater species datasets. The HC5 value for saltwater species (3.55ng TBTl(-1); lower confidence limit: 1.93ng TBTl(-1)) was significantly lower than that for

  11. Genetic variation of Lymnaea stagnalis tolerance to copper: A test of selection hypotheses and its relevance for ecological risk assessment.

    PubMed

    Côte, Jessica; Bouétard, Anthony; Pronost, Yannick; Besnard, Anne-Laure; Coke, Maïra; Piquet, Fabien; Caquet, Thierry; Coutellec, Marie-Agnès

    2015-10-01

    The use of standardized monospecific testing to assess the ecological risk of chemicals implicitly relies on the strong assumption that intraspecific variation in sensitivity is negligible or irrelevant in this context. In this study, we investigated genetic variation in copper sensitivity of the freshwater snail Lymnaea stagnalis, using lineages stemming from eight natural populations or strains found to be genetically differentiated at neutral markers. Copper-induced mortality varied widely among populations, as did the estimated daily death rate and time to 50% mortality (LT50). Population genetic divergence in copper sensitivity was compared to neutral differentiation using the QST-FST approach. No evidence for homogenizing selection could be detected. This result demonstrates that species-level extrapolations from single population studies are highly unreliable. The study provides a simple example of how evolutionary principles could be incorporated into ecotoxicity testing in order to refine ecological risk assessment. PMID:26074162

  12. Distribution of metals and accumulation of lead by different tissues in the freshwater snail Lymnaea stagnalis (L.)

    SciTech Connect

    Pyatt, F.B.; Pyatt, A.J.; Pentreath, V.W.

    1997-07-01

    The concentrations of several metals in different body tissues of the freshwater snail, Lymnaea stagnalis (L.), collected from an uncontaminated environment, were measured by electron probe X-ray microanalysis. Significant concentrations of the potentially toxic elements manganese, titanium, and copper were detected in all tissues, although they were not detectable in the water sampled at collection; bioaccumulation is thus evidenced. Highest concentrations of manganese and copper were present in the shell, while highest concentrations of titanium were present in the head and foot. Experimental snails were continuously exposed to lead chloride (lead at 5 ppm) for an experimental period of 3 weeks. Both elements were accumulated to different extents by the snail tissues but with high concentrations again in the head of the animals, and chloride also in the visceral hump. No significant alterations in the distribution of the other elements measured were observed in the lead chloride-exposed animals.

  13. 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.

  14. 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). PMID:24575245

  15. 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

  16. 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. PMID:18814203

  17. Characterization and response of antioxidant systems in the tissues of the freshwater pond snail (Lymnaea stagnalis) during acute copper exposure.

    PubMed

    Atli, Gülüzar; Grosell, Martin

    2016-07-01

    The response of enzymatic (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX and glutathione reductase, GR) and non-enzymatic responses (glutathione, GSH, oxidized glutathione, GSSG and GSH/GSSG) against acute Cu toxicity (2-90μg/mL for 48h) in different tissues of Lymnaea stagnalis were measured. Incubation conditions for enzymatic activity measurements were optimized for L. stagnalis tissues. Three examined tissues, the hepatopancreas, the foot muscle and the mantle, exhibited variable responses in antioxidant parameters as a function of Cu concentrations. The most responsive antioxidant enzymes were GPX and CAT while GR appeared less sensitive. In general antioxidant enzymes at higher Cu concentrations though GSH levels at lower Cu concentrations exhibited the greatest changes in hepatopancreas and foot muscle, respectively. All antioxidant enzymes except GR increased after exposure to the highest Cu concentration in mantle. Total and reduced GSH increased in hepatopancreas but decreased with GSH/GSSG ratios at all Cu concentrations in foot muscle. The present results show that antioxidants respond to acute Cu exposure at concentrations as low as 2μg Cu/L in adult L. stagnalis with variable responses in different tissues. Antioxidants both including enzymatic and non-enzymatic parameters may account, in part, for the high tolerance to acute metal exposure observed in adult L. stagnalis and could form suited biomarkers to evaluate the metal exposure and toxicity in aquatic environment even at relatively low level short term exposure. PMID:27108202

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

    PubMed

    Soldánová, Miroslava; Selbach, Christian; 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

  19. 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

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

    PubMed

    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

  1. 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. PMID:11708833

  2. 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

  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. PMID:24641838

  4. 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.

  5. 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

  6. Chronic hypoxia-induced alteration of presynaptic protein profiles and neurobehavioral dysfunction are averted by supplemental oxygen in Lymnaea stagnalis.

    PubMed

    Fei, G-H; Feng, Z-P

    2008-04-22

    Chronic hypoxia causes neural dysfunction. Oxygen (O(2)) supplements have been commonly used to increase the O(2) supply, yet the therapeutic benefit of this treatment remains controversial due to a lack of cellular and molecular evidence. In this study, we examined the effects of short-burst O(2) supplementation on neural behavior and presynaptic protein expression profiles in a simple chronic hypoxia model of snail Lymnaea stagnalis. We reported that hypoxia delayed the animal response to light stimuli, suppressed locomotory activity, induced expression of stress-response proteins, hypoxia inducible factor-1alpha (HIF-1alpha) and heat shock protein 70 (HSP70), repressed syntaxin-1 (a membrane-bound presynaptic protein) and elevated vesicle-associated membrane protein-1 (VAMP-1) (a vesicle-bound presynaptic protein) level. O(2) supplements relieved suppression of neural behaviors, and corrected hypoxia-induced protein alterations in a dose-dependent manner. The effectiveness of supplemental O(2) was further evaluated by determining time courses for recovery of neural behaviors and expression of stress response proteins and presynaptic proteins after relief from hypoxia conditions. Our findings suggest that O(2) supplement improves hypoxia-induced adverse alterations of presynaptic protein expression and neurobehaviors, however, the optimal level of O(2) required for improvement is protein specific and system specific. PMID:18343591

  7. Pesticide Mixture Toxicity in Surface Water Extracts in Snails (Lymnaea stagnalis) by an in Vitro Acetylcholinesterase Inhibition Assay and Metabolomics.

    PubMed

    Tufi, Sara; Wassenaar, Pim N H; Osorio, Victoria; de Boer, Jacob; Leonards, Pim E G; Lamoree, Marja H

    2016-04-01

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

  8. 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

  9. 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.

  10. 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. PMID:26944418

  11. Inhibitory modulation by FMRFamide of the voltage-gated sodium current in identified neurones in Lymnaea stagnalis.

    PubMed Central

    Brussaard, A B; Lodder, J C; ter Maat, A; de Vlieger, T A; Kits, K S

    1991-01-01

    1. The putative neurotransmitter FMRFa (Phe-Met-Arg-Phe-amide) caused an inhibitory modulation of the voltage-gated sodium current (INa) in central neurones, the peptidergic caudo dorsal cells (CDCs) of the mollusc Lymnaea stagnalis. FMRFa reduced INa at all command potentials tested (ranging from -35 to +20 mV), but the amplitude of the effect of FMRFa was voltage dependent, inhibition being stronger at more negative potentials (50 +/- 5% reduction at half-maximal INa activation versus 25 +/- 8% at the peak of the I-V curve). 2. INa current traces were well fitted by a Hodgkin & Huxley based model, using m3 activation kinetics and two time constants for inactivation. 3. The steady-state inactivation curve of INa was characterized by half-maximal inactivation at -42.5 +/- 1.81 mV and a slope factor of 4.6 +/- 0.28 mV. The fastest time constant of inactivation ran from 100 +/- 5 to 0.8 +/- 0.32 ms and the slower time constant from 505 +/- 45 to 4.8 +/- 1.40 ms in the range -40 to -5 mV. 4. FMRFa had no significant effect on either component of inactivation, nor on the voltage dependence of steady-state inactivation, nor on the maximal conductance. 5. FMRFa affected the activation of INa. The activation time constant was increased, ranging from 0.75 +/- 0.050 to 0.22 +/- 0.017 ms under control and from 0.91 +/- 0.043 to 0.31 +/- 0.038 ms with FMRFa in the voltage range -25 to +5 mV. The steady-state activation curve was shifted to less negative potentials: half-maximal activation occurred at -26.5 +/- 1.2 mV under control and at 23.6 +/- 1.4 mV with FMRFa; the slope factor (4.6 +/- 1.4 mV in control experiments) was not affected. The combination of slower activation kinetics and a shift in the voltage dependence of activation in the Hodgkin & Huxley based model, adequately explained the reduction of INa by FMRFa. 6. The physiological consequence is that the spiking threshold is increased, causing an arrest of on-going firing activity and a decrease in excitability

  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. 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

  14. Developmental toxicity of metaldehyde in the embryos of Lymnaea stagnalis (Gastropoda: Pulmonata) co-exposed to the synergist piperonyl butoxide.

    PubMed

    Hallett, Katrina C; Atfield, Andrew; Comber, Sean; Hutchinson, Thomas H

    2016-02-01

    Metaldehyde is a widely used molluscicide in countries where damage to crops from slugs and snails is a major problem associated with warm and wet winters. In the UK it is estimated that over 8% of the area covered by arable crops is treated with formulated granular bait pellets containing metaldehyde as the main active ingredient. Metaldehyde is hydrophilic (log Kow=0.12), water soluble (200 mg·L(-1) at 17 °C) and has been detected in UK surface waters in the concentration range of typically 0.2-0.6 μg·L(-1) (maximum 2.7 μg·L(-1)) during 2008-2011. In the absence of chronic data on potential hazards to non-target freshwater molluscs, a laboratory study was conducted to investigate the impact of metaldehyde on embryo development in the gastropod Lymnaea stagnalis (RENILYS strain) and using zinc as a positive control. L. stagnalis embryos were exposed to metaldehyde under semi-static conditions at 20±1 °C and hatching success and growth (measured as shell height and intraocular distance) examined after 21 d. Exposure concentrations were verified using HPLC and gave 21 d (hatching)NOEC and (hatching)LOEC mean measured values of 36 and 116 mg MET·L(-1), respectively (equal to the 21 d (shell height)NOEC and (shell height)LOEC values). For basic research purposes, a second group of L. stagnalis embryos was co-exposed to metaldehyde and the pesticide synergist piperonyl butoxide (PBO). Co-exposure to the PBO (measured concentrations between 0.47-0.56 mg·L(-1)) reduced hatching success from 100% to 47% and resulted in a 30% reduction in embryo growth (shell height) in snail embryos co-exposed to metaldehyde at 34-36 mg·L(-1) over 21 d. In conclusion, these data suggest mollusc embryos may have some metabolic detoxication capacity for metaldehyde and further work is warranted to explore this aspect in order to support the recent initiative to include molluscs in the OECD test guideline programme. PMID:26575636

  15. The bioaccumulation and fate of a branched 14C-p-nonylphenol isomer in Lymnaea stagnalis L.

    PubMed

    Lalah, Joseph O; Behechti, Akbar; Severin, Gabriele F; Lenoir, Dieter; Günther, Klaus; Kettrup, Antonius; Schramm, Karl-Werner

    2003-07-01

    A single branched isomer of p-nonylphenol, 4(3',6'-dimethyl-3'-heptyl)-phenol, previously identified by gas chromatography-mass spectrometry as one of the major constituent isomers in p-nonylphenol (constituting approximately 10% of all its isomers), was synthesized and used in studies of its bioaccumulation and excretion in the hermophroditic pond snail Lymnaea stagnalis L. Branched isomers of nonylphenol are perceived to have more estrogenlike toxicity than the straight-chain isomers in addition to being more resistant to biodegradation in the environment. With an average static exposure concentration of 104 microg/L (range: 92-116 microg/L) in water at 19 degrees C for 8 d, the uptake of the compound was found to be fairly rapid, reaching a peak concentration of 23,548 microg/kg of whole tissue wet weight after 5 d and a peak bioaccumulation factor (BAFw) of 242 (5,562, based on lipid weight) after 3 d. The uptake data fitted into a logarithmic expression C(t) = 5,231 ln(t) + 11,956, where C(t) is the amount of residues accumulated in whole tissue in micrograms per kilogram tissue wet weight after a period of time, t, and t is the period of exposure in days. By determination of the excretion of 14C-residues released in water and in feces, an average loss of 96% of the accumulated residues was achieved after 22 d of continuous exposure to clean water. By first-order kinetics analysis of the excretion data, an average half-life of excretion of 4.9 d was obtained. By high-performance liquid chromatography and gas-liquid chromatography-mass spectrometry, a catechol metabolite, 4(3',6'-dimethyl-3'-heptyl)-catechol, was detected in tissue extracts (after hydrolysis with beta-glucuronidase) and in feces, in addition to the parent isomer, suggesting that the isomer may have been metabolized by glucuronic acid conjugation and hydroxylation at the ortho position of its phenolic ring. PMID:12836966

  16. 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. PMID:10594932

  17. 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

  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. PMID:25229223

  19. 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

  20. Elimination of Biomphalaria pfeifferi, Bulinus tropicus and Lymnaea natalensis by the ampullarid snail, Marisa cornuarietis, in a man-made dam in northern Tanzania.

    PubMed

    Nguma, J F; McCullough, F S; Masha, E

    1982-03-01

    Marisa cornuarietis is a well known ampullarid competitor/predator of Biomphalaria glabrata in Puerto Rico. For the first time in Africa a flourishing population of Marisa has been established in a small, permanent, man-made dam at Kisangara, near Moshi, Tanzania. Prior to the release of M. cornuarietis in June 1977, this dam supported thriving populations of the pulmonate snail hosts Biomphalaria pfeifferi and Lymnaea natalensis; Bulinus tropicus and the melaniid Melanoides tuberculata were also common. Some 24 months after the establishment of Marisa the three pulmonate species had been eliminated; only M. tuberculata remained at about the same population density as originally recorded. Marisa has not caused any obvious adverse environmental impact in the dam. There is at present no valid evidence that this ampullarid would be a threat to local rice production, which is the only crop at risk, but carefully designed field trials should be undertaken to confirm or refute this view. In view of the vast number of permanent, lentic habitats throughout the Afrotropical region, which act as important transmission sites of schistosomiasis and fascioliasis, the role of Marisa cornuarietis as a cost-effective biological control agent in integrated control operations deserves henceforth to be energetically explored. PMID:6122367

  1. Differences in shell shape of naturally infected Lymnaea stagnalis (L.) individuals as the effect of the activity of digenetic trematode larvae.

    PubMed

    Zbikowska, Elzbieta; Zbikowski, Janusz

    2005-10-01

    The shells of Lymnaea stagnalis show great morphological variability. This phenomenon has been described as the result of an environmental influence. The main object of the present study was to compare some biometric data from shells of naturally infected and uninfected snails from 25 different lakes in the central part of Poland. The height of the shell, the height of the spiral, and the width of the shell were measured. Some inter- and intrapopulation differences among individuals were found. Greater variability of shell shape was observed among snails parasitized with digenean larvae than in nonparasitized ones. Snails infected with Echinoparyphium aconiatum, Echinostoma revolutum, Diplostomum pseudospathaceum, and Opisthioglyphe ranae differed in shell shape compared with uninfected individuals. Snails infected with Plagiorchis elegans did not differ from uninfected individuals. The same was true of snails in which the commensal oligochaete, Chaetogaster limnei, was found. The results of the present study support the assumption that the deformation of shells of the snails under study was in some way influenced by the presence of certain species of digenetic trematodes. PMID:16419747

  2. Training Lymnaea in the presence of a predator scent results in a long-lasting ability to form enhanced long-term memory.

    PubMed

    Forest, Jeremy; Sunada, Hiroshi; Dodd, Shawn; Lukowiak, Ken

    2016-06-01

    Lymnaea exposed to crayfish effluent (CE) gain an enhanced ability to form long-term memory (LTM). We test the hypothesis that a single CE exposure and operant conditioning training leads to long lasting changes in the capability of snails to form LTM when tested in pond water four weeks later. We trained both juvenile and adult snails with a single 0.5 h training session in CE and show that LTM was present 24 h later. Snails trained in a similar manner in just pond water show no LTM. We then asked if such training in CE conferred enhanced memory forming capabilities on these snails four weeks later. That is, would LTM be formed in these snails four weeks later following a single 0.5 h training session in pond water? We found that both adult and juvenile snails previously trained in CE one month previously had enhanced LTM formation abilities. The injection of a DNA methylation blocker, 5-AZA, prior to training in adult snails blocked enhanced LTM formation four weeks later. Finally, this enhanced LTM forming ability was not passed on to the next generation of snails. PMID:27138222

  3. 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

  4. 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. PMID:26925296

  5. [Studies upon behaviour of snails in anthropogenically changed water environment. 1. Locomotor activity of Lymnaea stagnalis (L.), with regard to subpopulations infected with developmental stages of digeneans].

    PubMed

    Pokora, Zbigniew

    2002-01-01

    The aim of the paper was to analyse the locomotor activity of snails, Lymnaea stagnalis, with regard to physico-chemical properties of water in an inhabited reservoir and parasitic infection. The material was collected in selected anthropogenic water environments situated in the Upper Silesian Industrial Region (sinkhole ponds, sand- and clay-excavations). The locomotor activity of each snail was analysed in laboratory conditions by designation of number of penetrated segments, marked in tanks filled with water originating from a given reservoir, during 15', with intervals of 1'. It was observed the significant relationship between locomotor activity of examined snails and the water carbonaceous hardness (r = -0,812, at range of the independent variable 173.0-863.5 mg CaCO3/dm3). Correlation coefficients with other physico-chemical parameters of water were close to zero. Locomotion of snails infected with developmental stages of digenetic trematodes was significantly lower comparing to non-infected individuals. Locomotor activity of these former ones was dependend more on degree of the digestive gland damage by the parasite than on the infection agent. PMID:16883702

  6. 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.

  7. 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

  8. 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. PMID:26934156

  9. 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. PMID:12387481

  10. 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. PMID:27267390

  11. 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

  12. 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. PMID:14762529

  13. 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. PMID:12937774

  14. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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

    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. 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

  18. 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

  19. Transient and big are key features of an invertebrate T-type channel (LCav3) from the central nervous system of Lymnaea stagnalis.

    PubMed

    Senatore, Adriano; Spafford, J David

    2010-03-01

    Here we describe features of the first non-mammalian T-type calcium channel (LCa(v)3) expressed in vitro. This molluscan channel possesses combined biophysical properties that are reminiscent of all mammalian T-type channels. It exhibits T-type features such as "transient" kinetics, but the "tiny" label, usually associated with Ba(2+) conductance, is hard to reconcile with the "bigness" of this channel in many respects. LCa(v)3 is 25% larger than any voltage-gated ion channel expressed to date. It codes for a massive, 322-kDa protein that conducts large macroscopic currents in vitro. LCa(v)3 is also the most abundant Ca(2+) channel transcript in the snail nervous system. A window current at typical resting potentials appears to be at least as large as that reported for mammalian channels. This distant gene provides a unique perspective to analyze the structural, functional, drug binding, and evolutionary aspects of T-type channels. PMID:20056611

  20. Chemoattraction and penetration of Echinostoma trivolvis and E. caproni cercariae in the presence of Biomphalaria glabrata, Helisoma trivolvis, and Lymnaea elodes dialysate.

    PubMed

    Fried, B; Frazer, B A; Reddy, A

    1997-01-01

    A petri-dish bioassay was used to study the chemoattraction and penetration of the cercariae of Echinostoma trivolvis and E. caproni in the presence of snail dialysates from Helisoma trivolvis (Pennsylvania and Colorado strains). Biomphalaria glabrata, and Lynmaea elodes. Significant chemoattraction was seen with E. trivolvis cercariae in the presence of all snail dialysates released from nonperforated dialysis sacs with a molecular-weight exclusion of 12,000. Under the same conditions, E. caproni was significantly attracted to B. glabrata and H. trivolvis (CO strain) but not to L. elodes or H. trivolvis (PA strain). Dialysis sacs were perforated with needles to allow the release of snail substances of all molecular weights into the bioassay. Cercariae of both species were significantly attracted to all snail dialysates released from perforated sacs. Moreover, cercariae entered these sacs and penetrated the snails, and 24 h later the percentage of cysts per snail species ranged from 70% to 83% for E. trivolvis and from 73% to 93% for E. caproni. Dialysates released from intact sacs were extracted in choloroform-methanol (2:1) to obtain hydrophilic and lipophilic fractions. When these extracts were placed on agar plugs in the bioassay, the lipophilic fraction, but not the hydrophilic fraction, was mainly chemoattractive. PMID:9039703

  1. Wasson's alternative candidates for soma.

    PubMed

    Riedlinger, T J

    1993-01-01

    Citing recently published challenges to R. Gordon Wasson's identification of Vedic soma as the psychoactive mushroom Amanita muscaria (fly-agaric), this article reviews unpublished letters by Wasson in which he considered and rejected other psychoactive plants as candidates, including the mint Lagochilus inebrians, Convolvulaceae (morning glory) seeds, the fungal parasite Claviceps purpurea (ergot), and especially the psilocybin mushroom Stropharia cubensis, known also as Psilocybe cubensis. Apart from their historical interest, these letters--from the Tina and Gordon Wasson Ethnomycological Collection at the Harvard Botanical Museum--demonstrate that Wasson remained open to refinements of his theory. PMID:8377083

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  3. Plant eR Genes That Encode Photorespiratory Enzymes Confer Resistance against Disease

    PubMed Central

    Taler, Dvir; Galperin, Marjana; Benjamin, Ido; Cohen, Yigal; Kenigsbuch, David

    2004-01-01

    Downy mildew caused by the oomycete pathogen Pseudoperonospora cubensis is a devastating foliar disease of cucurbits worldwide. We previously demonstrated that the wild melon line PI 124111F (PI) is highly resistant to all pathotypes of P. cubensis. That resistance was controlled genetically by two partially dominant, complementary loci. Here, we show that unlike other plant disease resistance genes, which confer an ability to resist infection by pathogens expressing corresponding avirulence genes, the resistance of PI to P. cubensis is controlled by enhanced expression of the enzymatic resistance (eR) genes At1 and At2. These constitutively expressed genes encode the photorespiratory peroxisomal enzyme proteins glyoxylate aminotransferases. The low expression of At1 and At2 in susceptible melon lines is regulated mainly at the transcriptional level. This regulation is independent of infection with the pathogen. Transgenic melon plants overexpressing either of these eR genes displayed enhanced activity of glyoxylate aminotransferases and remarkable resistance against P. cubensis. The cloned eR genes provide a new resource for developing downy mildew–resistant melon varieties. PMID:14688292

  4. Distribution of Parmarion cf. martensi (Pulmonata: Helicarionidae), a New Semi-Slug Pest on Hawai‘i Island, and Its Potential as a Vector for Human Angiostrongyliasis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The semi-slug, Parmarion cf. martensi Simroth, 1893, was first discovered on Oahu, Hawaii in 1996 and then on the island of Hawaii in 2004. This species has become abundant in eastern Hawaii island, reportedly displacing the Cuban slug, Veronicella cubensis (Pfeiffer, 1840) in some areas. A survey i...

  5. [Cucumber diseases diagnosis using multispectral imaging technique].

    PubMed

    Feng, Jie; Liao, Ning-Fang; Zhao, Bo; Luo, Yong-Dao; Li, Bao-Ju

    2009-02-01

    For a reliable diagnosis of plant diseases and insect pests, spectroscopy analysis technique and mutispectral imaging technique are proposed to diagnose five cucumber diseases, namely Trichothecium roseum, Sphaerotheca fuliginea, Cladosporium cucumerinum, Corynespora cassiicola and Pseudoperonospora cubensis. In the experiment, the cucumbers' multispectral images of 14 visible lights channels, near infrared channel and panchromatic channel were captured using narrow-band multispectral imaging system under standard observation environment. And the 5 cucumber diseases, healthy leaves and reference white were classified using their multispectral information, the distance, angle and relativity. The discrimination of Trichothecium roseum, Sphaerotheca fuliginea, Cladosporium cucumerinum, and reference white was 100%, and that of Pseudoperonospora cubensis and healthy leaves was 80% and 93.33% respectively. The mean correct discrimination of diseases was 81.90% when the distance and relativity were used together. The result shows that the method realized good accuracy in the cucumber diseases diagnosis. PMID:19445229

  6. 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. PMID:27447223

  7. Apertural features and surface texture of upper Paleogene biserial planktonic foraminifers: links between Chiloguembelina and Streptochilus.

    USGS Publications Warehouse

    Poore, R.Z.; Gosnell, L.B.

    1985-01-01

    Several upper Paleogene species of Chiloguembelina have an internal apertural plate that is very similar to the internal plate typical of the Neogene genus Streptochilus. The type species of Chiloguembelina, C. midwayensis midwayensis (Cushman), however, lacks any internal apertural structure or modifications. Therefore, the following 'Chiloguembelina', which have an internal plate, are assigned to Streptochilus: S. cubensis (Palmer), S. martini (Pijpers) and S. sp.aff. S. martini. -Authors

  8. [Fauna from the M/N "Vikheim"ship exploration in the northwest of the Colombian Caribbean].

    PubMed

    Alvarez-León, Ricardo; Rey-Carrasco, Iván

    2003-06-01

    Crustaceans (5 families, 10 species) and fish (38 families, 101 species) were captured (October 27 through November 3, 1979) from the R/V "Vikheim" (Cruise 7901) in the Colombian Caribbean, at a 10-630 m, depth range (Metapeneopsis shrimp, 26 species of fishes new for the trawling bottom and, Squalus cubensis, Chlorophthalmus agassizi, and, Neoepinnula orientalis), new fishes records for the Caribbean of Colombia. PMID:15162746

  9. 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.

  10. 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

  11. [Bounds of change in unsaturation index of fatty acid composition of phospholipids at adaptation of molluscs to biogenic and abiogenic factors of external medium].

    PubMed

    Chebotareva, M A; Zabelinskiĭ, S A; Shukoliukova, E P; Krivchenko, A I

    2011-01-01

    Comparative study of fatty acid composition of total phospholipids, as well as of phosphatidylcholine and phosphatidylethanolamine from hepatopancreas and leg muscle was performed on several representatives of gasteropods (Gastropoda) molluscs and bivalve (Bivalvia) mussel (Mytilus edulus). The objects of our study were marine litorins (Littorina saxsatilis) adapted to different temperature conditions of White Sea and Barents Sea, freshwater lymnaea (Lymnaea stagnalis) infested by Trematoda and mussels from White Sea and Black Sea. It was shown that depending on the existence conditions of studied tissue or lipid, the maximal change is observed in the percentage of saturated acids (4-83 %), the percentage of unsaturated acids was less expressed (1-14 %) and the changes in unsaturation index (UI) did not exceed 20 % on average. It was supposed that observed quantitative bounds of UI change under the action of different external factors is utmost for maintenance of membrane fluidity necessary for normal vital activity of cell, particularly in studied ectothermic molluscs. PMID:22145319

  12. A G protein-coupled receptor with low density lipoprotein-binding motifs suggests a role for lipoproteins in G-linked signal transduction.

    PubMed Central

    Tensen, C P; Van Kesteren, E R; Planta, R J; Cox, K J; Burke, J F; van Heerikhuizen, H; Vreugdenhil, E

    1994-01-01

    We have isolated and analyzed a cDNA from the central nervous system of the mollusc Lymnaea stagnalis encoding a putative receptor, which might be a natural hybrid between two different classes of receptor proteins. Preceded by a signal peptide, two types of repeated sequences are present in the N-terminal part of the protein. The first repeat displays a high sequence similarity to the extracellular binding domains of the low density lipoprotein receptor, which binds and internalizes cholesterol-containing apolipoproteins. The second repeat and the C-terminal part of the Lymnaea receptor are very similar to regions of a specific class of guanine nucleotide-binding protein-coupled receptors, the mammalian glycoprotein hormone receptors. The mRNA encoding the receptor is predominantly expressed in a small number of neurons within the central nervous system and to a lesser extent in the heart. Images PMID:8197140

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

    PubMed

    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

  14. 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

  15. 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

  16. 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.

  17. The entheomycological origin of Egyptian crowns and the esoteric underpinnings of Egyptian religion.

    PubMed

    Berlant, Stephen R

    2005-11-14

    In this paper, I theorize that the Egyptian White and Triple Crowns were originally primordia of the entheogenic Psilocybe (Stropharia) cubensis, which an Egyptian tale known as Cheops and the Magicians allegorically explained grew on barley, and that Osiris was the God of spiritual rebirth because he personified this and other entheogenic mushrooms. I go on to theorize that the plant known commonly as the Eye of Horus, which the Egyptians included in cakes and ales designed to spiritually rebirth the living and the dead, was an entheogenic mushroom cap entirely analogous, if not identical, to Soma. Finally, I explain why so many scholars failed to discern these identities and relationships for so long. PMID:16199133

  18. 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).

  19. Taxonomic revision of Coniceromyia Borgmeier (Diptera: Phoridae), with the description of three new species from Brazil.

    PubMed

    Ament, Danilo César; Amorim, Dalton De Souza

    2016-01-01

    The 55 known species of Coniceromyia are herein revised. Three new species from the Atlantic Forest in Brazil are described-C. apioneura, sp.nov., C. neofusca, sp.nov. and C. tanycrossa, sp.nov.-and fourteen species are redescribed. Most of the species have foreleg, wing, hind femur, and male terminalia illustrated. Characters previously unnoticed are described for the first time. Coniceromyia cubensis Brues, previously accepted as a synonym of C. latimana (Malloch), has its status reinstated. Taxonomic problems in the genus are addressed, including the condition of the damaged holotypes of C. boliviana Borgmeier and C. vespertilio Schmitz, and our inability to associate males with the female holotypes of C. arizonensis Borgmeier, C. fusca Borgmeier and C. grenadensis (Brues). The holotypes of Coniceromyia angularis Borgmeier & Prado and Coniceromyia laticosta Prado are considered to be lost. PMID:27394322

  20. Ecological modulation of environmental stress: interactions between ultraviolet radiation, epibiotic snail embryos, plants and herbivores.

    PubMed

    Wahl, Martin

    2008-05-01

    1. The distribution of egg masses of the freshwater snails Lymnaea stagnalis and Planorbarius corneus on the undersides of water lily leaves (e.g. Nuphar lutea) is related to the prevalence of the leaf-mining beetle Galerucella nymphaeae. 2. When given the choice, Planorbarius significantly avoids leaves that were infested by the mining beetle. Conversely, Lymnaea did not discriminate against mined leaves. 3. Intact Nuphar leaves block over 95% of incident ultraviolet radiation. Yet, ultraviolet transmission reaches almost 100% under beetle mining scars. These are several times wider than snail embryos. 4. When exposed to natural sunlight, Lymnaea embryos proved to be resistant to ambient ultraviolet, while Planorbarius embryos were rapidly killed. Thus, one selective advantage of Planorbarius discrimination against mined leaves when depositing its eggs could be the avoidance of ultraviolet radiation passing through mining scars. 5. Other mining-related modifications of the leaves, reduced area, decreased longevity, altered aufwuchs (i.e. biofilm and epibionts) are discussed but seem less relevant for the oviposition preference of Planorbarius. 6. The discriminatory behaviour of this snail species was triggered by water-borne cues emitted by the damaged leaf, not by the eggs or larvae of the beetle. 7. This study illustrates how environmental stress on a given species, ultraviolet radiation in this case, can be ecologically buffered (shading by Nuphar) or enhanced (reduction of Nuphar shading through beetle mining) by associated species. It highlights how the impact of a given stress depends on the identity of the target species as well as on the identity and role of other species in the community. PMID:18217942

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

    PubMed Central

    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. PMID:25405008

  2. 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.

  3. Infection of snails with bird schistosomes and the threat of swimmer's itch in selected Polish lakes.

    PubMed

    Zbikowska, Elzbieta

    2004-01-01

    Studies of selected species of Lymnaeidae and Planorbidae showed that infection with bird schistosomes occurred in 14 of the 26 Polish lakes studied. In Planorbarius corneus larvae of Bilharziella polonica were found, and in Lymnaea stagnalis and Radix auricularia larvae of Trichobilharzia ocellata. In spite of their comparatively low prevalence, cercariae, potentially pathogenic to humans, may have caused dermatitis in patients registered in one of the regions under study. The low prevalence of infection among the host snails may have been compensated for by the enormous number of cercariae released by them, which, moreover, showed a long-lasting viability, particularly at low ambient temperature. PMID:14598171

  4. [Interrelations in the Fasciola hepatica-water snail system].

    PubMed

    Iavorskiĭ, I P

    1989-01-01

    Peculiarities of relationships in the "Fasciola hepatica-Lymnaea truncatula" system were studied by means of hystological and histochemical methods. Trematodes cause deep histopathological and histochemical changes of the injured organs of L. truncatula. They are determined by mechanical destruction of mollusc's tissues under the effect of parasites and by intoxication of animals with metabolites of parasites. Under the effect of parasites the content of glycogen and phospholipids in hosts' tissues decreases while the concentration of neutral fats increases. In most cases, however, the infected hosts remain viable that under normal ecological conditions results in the preservation of the "F. hepatica-L. truncatula" system. PMID:2812859

  5. 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)

  6. Resistance of pulmonate snail populations to repeated treatments of copper sulfate

    NASA Astrophysics Data System (ADS)

    Blankespoor, Harvey D.; Cameron, Stephen C.; Cairns, John

    1985-09-01

    Two species of pulmonate snails, Lymnaea cat-ascopium and Physa integra, were collected from Douglas and Houghton Lakes. Snail populations from the former lake (pristine) had never been exposed to copper sulfate, whereas those from the latter one (treated) had been subjected to the molluscicide for more than 40 years. Molluscs from the treated lake were more resistant to the copper at concentrations of 0.5 and 1.0 ppm than those from the pristine lake. Furthermore, larger lymnaeids had a higher survival rate than smaller ones.

  7. 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.

  8. 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. PMID:16253436

  9. 3-O-methyl sugars as constituents of glycoproteins. Identification of 3-O-methylgalactose and 3-O-methylmannose in pulmonate gastropod haemocyanins.

    PubMed

    Hall, R L; Wood, E J; Kamberling, J P; Gerwig, G J; Vliegenthart, F G

    1977-07-01

    In addition to the already knownonosaccharides fucose, xylose, mannose, galactose, glucose, N-acetylgalactosamine and N-acetylglucosamine, the carbohydrate part of the haemocyanin from Helix pomatia (Roman snail) contains 3-O-methylgalactose, and that from Lymnaea stagnalis (a freshwater snail) 3-O-methylgalactose and 3-O-methylmannose. The 3-O-methyl sugars were identified by g.l.c.-mas spectrometry of the corresponding trimethylsilyl methyl glycosides and the alditol acetates, and by co-chromatography with the synthetic reference substances. PMID:889564

  10. [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. PMID:20143583

  11. 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

  12. [Lipids composition and speed of energy metabolism in gastropods].

    PubMed

    Arakelova, E S

    2008-01-01

    Lipid composition of digestive gland and pedal muscle of two northern freshwater pulmonate snails Lymnaea stagnalis and Lymnaea ovata and three marine prosobranch gastropods Littorina obtusata, Littorina littorea, Buccinum undatum from the White Sea was studied. The species differ in ecology, particularly in trophic nabits and motor activity. The content of triacilglycerides both in digestive gland and pedal was higher in littoral dwellers Littorina the activity of which depends on the tide level. The phospholipids content in digestive gland does not differ in quantity in all cases and does not relate to type of feeding or resource quality. In a pedal muscle of marine species the quantity of common phospholipids is higher in comparison with the freshwater ones. The amount of total phospholipids in pedal muscle correlates with mass of metabolic inert formation which constitutes a part of whole mass of snails. The presence of massive shell enhances demands in energy needed for supporting movement and activity. Because the intensity of energy metabolism is related to quantity of total phospholipids, mitochondria and activity of their oxidizing ferments, the presence of thick shell in marine snails together with motor activity costs more in terms of energy than in freshwater snails with thin shell. This hypothesis is supported by the higher specific rate of oxygen consumption in marine snails than in freshwaters. PMID:19140337

  13. Bioanalytical Applications of Real-Time ATP Imaging Via Bioluminescence

    SciTech Connect

    Jason Alan Gruenhagen

    2003-12-12

    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. Ca{sup 2+} imaging along with ATP imaging revealed that activation of phospholipase C and induction of intracellular Ca{sup 2+} 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{sup +} 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 functionalized Cd

  14. 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

  15. Immune defence under extreme ambient temperature

    PubMed Central

    Seppälä, Otto; Jokela, Jukka

    2011-01-01

    Owing to global climate change, the extreme weather conditions are predicted to become more frequent, which is suggested to have an even greater impact on ecological interactions than the gradual increase in average temperatures. Here, we examined whether exposure to high ambient temperature affects immune function of the great pond snail (Lymnaea stagnalis). We quantified the levels of several immune traits from snails maintained in a non-stressful temperature (15°C) and in an extreme temperature (30°C) that occurs in small ponds during hot summers. We found that snails exposed to high temperature had weaker immune defence, which potentially predisposes them to infections. However, while phenoloxidase and antibacterial activity of snail haemolymph were reduced at high temperature, haemocyte concentration was not affected. This suggests that the effect of high temperature on snail susceptibility to infections may vary across different pathogens because different components of invertebrate immune defence have different roles in resistance. PMID:20610417

  16. Noninvasive neuroelectronic interfacing with synaptically connected snail neurons immobilized on a semiconductor chip

    PubMed Central

    Zeck, Günther; Fromherz, Peter

    2001-01-01

    A hybrid circuit of a semiconductor chip and synaptically connected neurons was implemented and characterized. Individual nerve cells from the snail Lymnaea stagnalis were immobilized on a silicon chip by microscopic picket fences of polyimide. The cells formed a network with electrical synapses after outgrowth in brain conditioned medium. Pairs of neurons were electronically interfaced for noninvasive stimulation and recording. Voltage pulses were applied to a capacitive stimulator on the chip to excite the attached neuron. Signals were transmitted in the neuronal net and elicited an action potential in a second neuron. The postsynaptic excitation modulated the current of a transistor on the chip. The implementation of the silicon-neuron-neuron-silicon circuit constitutes a proof-of-principle experiment for the development of neuroelectronic systems to be used in studies on neuronal signal processing, neurocomputation, and neuroprosthetics. PMID:11526244

  17. Helobdella nilae and Alboglossiphonia conjugata leeches as biological agents for snails control.

    PubMed

    Abd-Allah, Karim F; Saleh, Mohamed H; El-Hamshary, Azza M S; Negm-Eldin, Mohsen M; El-Fakahany, Amany F; Abdel-Tawab, Ahmed H; Abdel-Maboud, Amina I; Aly, Nagwa S M

    2009-04-01

    The efficacy of leeches, as biological agents, in control of snail intermediate hosts of schistosomiasis (Bulinus truncatus, Biomphalaria alexandrina) and fascioliasis (Lymnaea natalensis) as well as their effect on the non-target snails Physa acuta, Melanioides tuberculata and Cleopatra bulimoides was evaluated. Two glossiphoniid snail leeches, Helobdella nilae and Alboglossiphonia conjugata were used. They destroyed egg masses and young snails more rapidly than adult ones. H. nilae showed a stronger destructive effect than A. conjugata. In a descending order, it preferred L. natalensis followed by B. truncatus, B. alexandrina, Ph. acuta, M. tuberculata and lastly C. bulimoides. But, A. conjugata preferred L. natalensis followed by B. truncatus, Ph. acuta, M. tuberculata, B. alexandrina and lastly C. bulimoides. The detailed diagnostic morphology and biology of the two leeches were given. PMID:19530628

  18. 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).

  19. A flavanoid component of chocolate quickly reverses an imposed memory deficit.

    PubMed

    Knezevic, Bogdan; Komatsuzaki, Yoshimasa; de Freitas, Emily; Lukowiak, Ken

    2016-03-15

    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. PMID:26823103

  20. Demonstration of substances immunologically related to the identified arthropod neuropeptides AKH/RPCH in the CNS of several invertebrate species.

    PubMed

    Schooneveld, H; van Herp, F; van Minnen, J

    1987-03-17

    The occurrence of adipokinetic hormone (AKH) and red pigment concentrating hormone (RPCH)-like neuropeptides in the central nervous system of different invertebrate species other than insects was investigated immunocytochemically with polyclonal antisera to N- and C-terminal regions of the AKH molecule. Substances reacting with the C-terminal specific antiserum code 241 were present in neurons of the pond snail, Lymnaea stagnalis, the sowbug Porcellio scaber, the centiped Lithobius forficatus and the crayfish Astacus leptodactylus. Substances revealed by the N-terminal specific antiserum code 433 were demonstrated in the latter two species. The distribution of immunoreactive substances in neuropile areas of several ganglia suggests that these substances act as neurotransmitter/neuromodulator. Their presence in neurohemal organs such as the periphery of the pedal and visceral nerves in the pond snail and in the sinus gland of the crayfish suggests a neurohormonal role in these species. PMID:3567623

  1. 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". PMID:1822928

  2. 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. PMID:27574544

  3. The activity of isolated snail neurons controlling locomotion is affected by glucose

    PubMed Central

    Dyakonova, Varvara; Hernádi, László; Ito, Etsuro; Dyakonova, Taisia; Zakharov, Igor; Sakharov, Dmitri

    2015-01-01

    The involvement of serotonin in mediating hunger-related changes in behavioral state has been described in many invertebrates. However, the mechanisms by which hunger signals to serotonergic cells remain unknown. We tested the hypothesis that serotonergic neurons can directly sense the concentration of glucose, a metabolic indicator of nutritional state. In the snail Lymnaea stagnalis, we demonstrate that completely isolated pedal serotonergic neurons that control locomotion changed their biophysical characteristics in response to glucose application by lowering membrane potential and decreasing the firing rate. Additionally, the excitatory response of the isolated serotonergic neurons to the neuroactive microenvironment of the pedal ganglia was significantly lowered by glucose application. Because hunger has been reported to increase the activity of select neurons and their responses to the pedal ganglia microenvironment, these responses to glucose are in accordance with the hypothesis that direct glucose signaling is involved in the mediation of the hunger-related behavioral state. PMID:27493515

  4. 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. PMID:2626572

  5. 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. PMID:11495286

  6. 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. PMID:26515556

  7. 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.

  8. 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. PMID:23901391

  9. 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

  10. Studies in genera similar to Torula: Bahusaganda, Bahusandhika, Pseudotorula, and Simmonsiella gen. nov.

    PubMed

    Crane, J Leland; Miller, Andrew N

    2016-06-01

    A generic key is presented to delimit Torula from seven hyphomycete genera whose type species were at one time included in the genus or whose conidium ontogeny and conidium development appear similar or superficially similar to that of Torula herbarum, the type of the genus. In Bahusaganda, two new species are described (B. elliseverhartii and B. simmonsii spp. nov.) and three new combinations made (B. ambrosiae, B. elaeodes, and B. heteromorpha combs. nov.). In Bahusandhika, one new species (B. hughesii sp. nov.) is introduced, and two new combinations made (B. rhombica and B. terrestris combs. nov.), along with emendations in the circumscription of B. caligans and B. intercalaris. Latorua is considered synonymous with Bahusandhika. In Pseudotorula, one new combination is made (P. sundara comb. nov.), and one emendation proposed (P. helica). The transfer of Dwayabeeja sundara, the type species of the genus, to Pseudotorula will require a new generic name to be introduced for D. aethiopica and D. cubensis. The new generic name Simmonsiella is established for Torula ndjilensis. Bahusandhika compacta is shown to be synonymous with Torula verrucospora. PMID:27433439

  11. 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. PMID:26615751

  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. 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. PMID:26429524

  14. [Horticultural plant diseases multispectral classification using combined classified methods].

    PubMed

    Feng, Jie; Li, Hong-Ning; Yang, Wei-Ping; Hou, De-Dong; Liao, Ning-Fang

    2010-02-01

    The research on multispectral data disposal is getting more and more attention with the development of multispectral technique, capturing data ability and application of multispectral technique in agriculture practice. In the present paper, a cultivated plant cucumber' familiar disease (Trichothecium roseum, Sphaerotheca fuliginea, Cladosporium cucumerinum, Corynespora cassiicola, Pseudoperonospora cubensis) is the research objects. The cucumber leaves multispectral images of 14 visible light channels, near infrared channel and panchromatic channel were captured using narrow-band multispectral imaging system under standard observation and illumination environment, and 210 multispectral data samples which are the 16 bands spectral reflectance of different cucumber disease were obtained. The 210 samples were classified by distance, relativity and BP neural network to discuss effective combination of classified methods for making a diagnosis. The result shows that the classified effective combination of distance and BP neural network classified methods has superior performance than each method, and the advantage of each method is fully used. And the flow of recognizing horticultural plant diseases using combined classified methods is presented. PMID:20384138

  15. 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. PMID:22150235

  16. What are the elements of motivation for acquisition of conditioned taste aversion?

    PubMed

    Mita, Koichi; Okuta, Akiko; Okada, Ryuichi; Hatakeyama, Dai; Otsuka, Emi; Yamagishi, Miki; Morikawa, Mika; Naganuma, Yuki; Fujito, Yutaka; Dyakonova, Varvara; Lukowiak, Ken; Ito, Etsuro

    2014-01-01

    The pond snail Lymnaea stagnalis is capable of being classically conditioned to avoid food and to consolidate this aversion into a long-term memory (LTM). Previous studies have shown that the length of food deprivation is important for both the acquisition of taste aversion and its consolidation into LTM, which is referred to as conditioned taste aversion (CTA). Here we tested the hypothesis that the hemolymph glucose concentration is an important factor in the learning and memory of CTA. One-day food deprivation resulted in the best learning and memory, whereas more prolonged food deprivation had diminishing effects. Five-day food deprivation resulted in snails incapable of learning or remembering. During this food deprivation period, the hemolymph glucose concentration decreased. If snails were fed for 2days following the 5-day food deprivation, their glucose levels increased significantly and they exhibited both learning and memory, but neither learning nor memory was as good as with the 1-day food-deprived snails. Injection of the snails with insulin to reduce glucose levels resulted in better learning and memory. Insulin is also known to cause a long-term enhancement of synaptic transmission between the feeding-related neurons. On the other hand, injection of glucose into 5-day food-deprived snails did not alter their inability to learn and remember. However, if these snails were fed on sucrose for 3min, they then exhibited learning and memory formation. Our data suggest that hemolymph glucose concentration is an important factor in motivating acquisition of CTA in Lymnaea and that the action of insulin in the brain and the feeding behavior are also important factors. PMID:24176925

  17. 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. PMID:25369208

  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. PMID:25504929

  19. 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. PMID:20653234

  20. Transmission dynamics of Fasciola hepatica in the Plateau Region of Mexico. Effect of weather and treatment of mammals under current farm management.

    PubMed

    Cruz-Mendoza, Irene; Quiroz-Romero, Héctor; Correa, Dolores; Gómez-Espinoza, Guillermo

    2011-01-10

    The aim of the present work was to study the dynamics of Fasciola hepatica natural infection in ovines, caprines, bovines and two mollusc species, Lymnaea (Fossaria) humilis and Lymnaea (F.) bulimoides, from 2004 to mid 2007 under normal farm management conditions, and the relation to climate changes. The study was performed in a research centre in the plateau of Mexico. Temperature and rainfall were registered every month, as well as the number and intensity of infection in livestock and molluscs, as determined by coprology and direct observation/cercariae release, respectively. The first two years mammals were treated with clorsulon/ivermectin because the animals were harbouring concomitant intestinal nematode infections and this was the available drug combination. During the second period treatment was with triclabendazole. The temperature ranged from around cero to 30 °C, except during September 2005 to January 2006, when a cold climate prevailed. The rainfall augmented every year in July-August, and slightly in April, 2006. Lymneid snails appeared during or immediately after the rainfall peaks of 2004 and 2006, while few L. humilis and no L. bulimoides were present during the same period of 2005, probably because it was cold. A total of 15564 cercariae were released from molluscs during the wet time of 2004, 76 during 2005 and 368 in 2006. Several peaks of infection in mammals were observed, most occurring up to 4 months after the snails had disappeared. As expected, the weather had strong impact on snails and then on livestock infection. Also, treatment given to livestock was related to reduced cercarieae release five months later. Therefore, the combination of treatment and inspection of snails in the biotopes where the livestock graze may facilitate control of fasciolosis under current farm management. PMID:21055879

  1. [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. PMID:26995910

  2. 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.

  3. 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. PMID:22679601

  4. 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

  5. Identification of the role of C/EBP in neurite regeneration following microarray analysis of a L. stagnalis CNS injury model

    PubMed Central

    2012-01-01

    Background Neuronal regeneration in the adult mammalian central nervous system (CNS) is severely compromised due to the presence of extrinsic inhibitory signals and a reduced intrinsic regenerative capacity. In contrast, the CNS of adult Lymnaea stagnalis (L. stagnalis), a freshwater pond snail, is capable of spontaneous regeneration following neuronal injury. Thus, L. stagnalis has served as an animal model to study the cellular mechanisms underlying neuronal regeneration. However, the usage of this model has been limited due to insufficient molecular tools. We have recently conducted a partial neuronal transcriptome sequencing project and reported over 10,000 EST sequences which allowed us to develop and perform a large-scale high throughput microarray analysis. Results To identify genes that are involved in the robust regenerative capacity observed in L. stagnalis, we designed the first gene chip covering ~15, 000 L. stagnalis CNS EST sequences. We conducted microarray analysis to compare the gene expression profiles of sham-operated (control) and crush-operated (regenerative model) central ganglia of adult L. stagnalis. The expression levels of 348 genes were found to be significantly altered (p < 0.05) following nerve injury. From this pool, 67 sequences showed a greater than 2-fold change: 42 of which were up-regulated and 25 down-regulated. Our qPCR analysis confirmed that CCAAT enhancer binding protein (C/EBP) was up-regulated following nerve injury in a time-dependent manner. In order to test the role of C/EBP in regeneration, C/EBP siRNA was applied following axotomy of cultured Lymnaea PeA neurons. Knockdown of C/EBP following axotomy prevented extension of the distal, proximal and intact neurites. In vivo knockdown of C/EBP postponed recovery of locomotory activity following nerve crush. Taken together, our data suggest both somatic and local effects of C/EBP are involved in neuronal regeneration. Conclusions This is the first high-throughput microarray

  6. 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

  7. 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

  8. Neuron changes in a mollusk in response to proteolytic enzymes.

    PubMed

    Sotnikov, O S; Lukovnikova, M V; Vasyagina, N Yu; Laktionova, A A; Paramonova, N M

    2010-09-01

    The aims of the present work were to investigate the structure of neurons after treatment with proteases and to identify possible recovery of interneuronal syncytial connections. In the first series of experiments, phase-contrast microscopy studies of live dissociated neurons from ganglia of the mollusk Lymnaea stagnalis treated with 0.4% pronase solution demonstrated retraction of nerve processes and biphasic changes in cell body volume. At stage I, at an average of 82.5 min, neuron body volume decreased by 12.1%, after which it increased by a mean of 14.1%. Signs of neuron viability in Ringer's solution were seen for an average of 828 min; survival time in pronase solution was 1.4 times shorter. In the second series of experiments, studies of neuron ultrastructure showed many cases of persistence of mitochondria, the rough and smooth endoplasmic reticulum (ER), Golgi complex, light and granular vesicles, nuclear structure, and neuroplasm optical density. Cells coming close together after centrifugation formed intracellular clefts of uniform width (about 20 nm). There were very rare cases of points at which membranes came into contact. There were no signs of syncytial connections. Lengthening and fusion of smooth ER cisterns separated fragments of neuron bodies from relatively undamaged cells. Some neurons were damaged, with multiple vacuoles formed form swollen mitochondria and ER cisterns. Fragments of nerve processes formed on dissociation were surrounded by a normal outer cell membrane. PMID:20652422

  9. Predicting dietborne metal toxicity from metal influxes.

    PubMed

    Croteau, Marie-Noële; Luoma, Samuel N

    2009-07-01

    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 (k(uf)) were, respectively, 3.3 and 2.3 times higher than thatfor Cu. Detoxification rate constants (k(detox)) were similar among metals and appeared 100 times higher than efflux rate constants (K(e)). 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. PMID:19673285

  10. Estimating Genetic and Maternal Effects Determining Variation in Immune Function of a Mixed-Mating Snail

    PubMed Central

    Seppälä, Otto; Langeloh, Laura

    2016-01-01

    Evolution of host defenses such as immune function requires heritable genetic variation in them. However, also non-genetic maternal effects can contribute to phenotypic variation, thus being an alternative target for natural selection. We investigated the role of individuals’ genetic background and maternal effects in determining immune defense traits (phenoloxidase and antibacterial activity of hemolymph), as well as in survival and growth, in the simultaneously hermaphroditic snail Lymnaea stagnalis. We utilized the mixed mating system of this species by producing full-sib families in which each parental snail had produced offspring as both a dam and as a sire, and tested whether genetic background (family) and non-genetic maternal effects (dam nested within family) explain trait variation. Immune defense traits and growth were affected solely by individuals’ genetic background. Survival of snails did not show family-level variation. Additionally, some snails were produced through self-fertilization. They showed reduced growth and survival suggesting recessive load or overdominance. Immune defense traits did not respond to inbreeding. Our results suggest that the variation in snail immune function and growth was due to genetic differences. Since immune traits did not respond to inbreeding, this variation is most likely due to additive or epistatic genetic variance. PMID:27551822

  11. Nickel toxicity to benthic organisms: The role of dissolved organic carbon, suspended solids, and route of exposure.

    PubMed

    Custer, Kevin W; Hammerschmidt, Chad R; Burton, G Allen

    2016-01-01

    Nickel bioavailability is reduced in the presence of dissolved organic carbon (DOC), suspended solids (TSS), and other complexing ligands; however, no studies have examined the relative importance of Ni exposure through different compartments (water, sediment, food). Hyalella azteca and Lymnaea stagnalis were exposed to Ni-amended water, sediment, and food, either separately or in combination. Both organisms experienced survival and growth effects in several Ni compartment tests. The DOC amendments attenuated L. stagnalis Ni effects (survival, growth, and (62)Ni bioaccumulation), and presence of TSS exposures demonstrated both protective and synergistic effects on H. azteca and L. stagnalis. (62)Ni trophic transfer from food to H. azteca and L. stagnalis was negligible; however, bioaccumulating (62)Ni was attributed to (62)Ni-water ((62)Ni flux from food), (62)Ni-TSS, and (62)Ni-food. Overall, H. azteca and L. stagnalis Ni compartment toxicity increased in the following order: Ni-water > Ni-sediment > Ni-all (water, sediment, food) > Ni-food. PMID:26552544

  12. 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

    2016-02-01

    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 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. PMID:26698541

  13. 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. PMID:25869798

  14. Trematode infections in freshwater snails and cattle from the Kafue wetlands of Zambia during a period of highest cattle-water contact.

    PubMed

    Phiri, A M; Phiri, I K; Chota, A; Monrad, J

    2007-03-01

    A total of 984 snails, comprising nine species, were collected from six areas in the Kafue wetlands between August and October 2003 to assess larval trematode infections. Of these, 135 (13.7%) were positive. Most trematode infections were recorded from Lymnaea natalensis (42.8%), which harboured four of the five morphologically different cercariae found. No trematodes were recovered from Bellamya capillata, Biomphalaria pfeifferi, Melanoides tuberculata, Physa acuta and Cleopatra nswendweensis. One snail (0.2%) of 416 Bulinus snails shed brevifurcate-apharyngeate distome cercariae while three (0.7%) shed amphistomes. Gymnocephalous and longifurcate-pharyngeate distome were the commonest types of cercariae recorded while xiphidiocercaria was the least common. The highest prevalence rates of F. gigantica (68.8%) and amphistomes (50.0%) in cattle (n = 101) were in Chiyasa while those in Kaleya had the lowest (9.1 and 18.2%, respectively). In most habitats, infections were recorded in both cattle and snails. Critical determinants of infection may have been the distance of settlements and/or cattle kraals, the number of animals in nearby homesteads and the presence of susceptible host snails. This study suggests that fascioliasis and amphistomiasis could be major constraints of cattle production in the Kafue wetlands because favourable factors were available to introduce and maintain the infections. It further provides a starting point for some comprehensive studies on snail-related aspects of transmission and snail host ecology in Zambia. PMID:17381873

  15. 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. PMID:19530615

  16. 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.

  17. [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. PMID:17867501

  18. A conserved set of maternal genes? Insights from a molluscan transcriptome.

    PubMed

    Liu, M Maureen; Davey, John W; Jackson, Daniel J; Blaxter, Mark L; Davison, Angus

    2014-01-01

    The early animal embryo is entirely reliant on maternal gene products for a 'jump-start' that transforms a transcriptionally inactive embryo into a fully functioning zygote. Despite extensive work on model species, it has not been possible to perform a comprehensive comparison of maternally-provisioned transcripts across the Bilateria because of the absence of a suitable dataset from the Lophotrochozoa. As part of an ongoing effort to identify the maternal gene that determines left-right asymmetry in snails, we have generated transcriptome data from 1 to 2-cell and ~32-cell pond snail (Lymnaea stagnalis) embryos. Here, we compare these data to maternal transcript datasets from other bilaterian metazoan groups, including representatives of the Ecydysozoa and Deuterostomia. We found that between 5 and 10% of all L. stagnalis maternal transcripts (~300-400 genes) are also present in the equivalent arthropod (Drosophila melanogaster), nematode (Caenorhabditis elegans), urochordate (Ciona intestinalis) and chordate (Homo sapiens, Mus musculus, Danio rerio) datasets. While the majority of these conserved maternal transcripts ("COMATs") have housekeeping gene functions, they are a non-random subset of all housekeeping genes, with an overrepresentation of functions associated with nucleotide binding, protein degradation and activities associated with the cell cycle. We conclude that a conserved set of maternal transcripts and their associated functions may be a necessary starting point of early development in the Bilateria. For the wider community interested in discovering conservation of gene expression in early bilaterian development, the list of putative COMATs may be useful resource. PMID:25690965

  19. 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

  20. 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

    2013-04-01

    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% (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. PMID:23458345

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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

    2016-08-01

    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 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. PMID:27385165

  6. 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

  7. 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. PMID:26160679

  8. Paramphistomum daubneyi: characteristics of infection in three lymnaeid species

    PubMed Central

    Sanabria, R.; Titi, A.; Mekroud, A.; Vignoles, P.; Dreyfuss, G.; Rondelaud, D.; Romero, J.

    2012-01-01

    Experimental infections of two South American lymnaeids (Lymnaea neotropica and L. viatrix var. ventricosa) with Paramphistomum daubneyi were carried out to determine if these snail species could sustain larval development of this digenean and, if so, to specify their potential for cercarial production. A French population of Galba truncatula infected and raised according to the same protocol served as controls. In both experiments, prevalence of P. daubneyi infections in snails did not significantly differ from each other. In snail groups evaluated for cercarial shedding (first experiment), a significantly lower number of shed cercariae was noted for L. neotropica, while those from G. truncatula and L. v. ventricosa did not differ significantly from each other. Dissection of infected snails at day 65 post-exposure at 20 °C (second experiment) found significantly lower burdens of P. daubneyi rediae and cercariae in the bodies of L. neotropica than in those of G. truncatula and L. v. ventricosa. Compared to total cercarial production observed in dissected snails, the percentage of cercariae which exited from snails was 75.6% for G. truncatula, 21.6% for L. neotropica, and 91.4% for L. v. ventricosa. This last species seems to be a good candidate for metacercarial production of P. daubneyi. PMID:23193532

  9. 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

  10. 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. PMID:26874318

  11. [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. PMID:25859605

  12. 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. PMID:11411948

  13. 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. PMID:26536397

  14. 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. PMID:26573519

  15. Relative reproductive success of co-infecting parasite genotypes under intensified within-host competition.

    PubMed

    Seppälä, Otto; Louhi, Katja-Riikka; Karvonen, Anssi; Rellstab, Christian; Jokela, Jukka

    2015-12-01

    In nature, host individuals are commonly simultaneously infected with more than one genotype of the same parasite species. These co-infecting parasites often interact, which can affect their fitness and shape host-parasite ecology and evolution. Many of such interactions take place through competition for limited host resources. Therefore, variation in ecological factors modifying the host resource level could be important in determining the intensity of competition and the outcome of co-infections. We tested this hypothesis by measuring the relative reproductive success of co-infecting genotypes of the trematode parasite Diplostomum pseudospathaceum in its snail host Lymnaea stagnalis while experimentally manipulating snail resource level using contrasting feeding treatments (ad libitum food supply, no food). We found that food deprivation constrained the overall parasite within-host reproduction as the release of parasite transmission stages (cercariae) was reduced. This indicates intensified competition among the parasite genotypes. The genotypic composition of the released cercariae, however, was not affected by the feeding treatments. This suggests that in this system, the relative reproductive success of co-infecting parasite genotypes, which is an important component determining their fitness, is robust to variation in ecological factors modifying the strength of resource competition. PMID:26296607

  16. Efficacy of temperature, and two commonly used molluscicides and fertilizers on Fasciola gigantica eggs.

    PubMed

    Hassan, Aly A; Shoukary, Nahla M; Ismail, Nahed M M

    2008-08-01

    This study evaluated the effect of temperature, molluscicides (Copper sulphate and Niclosamide), fertilizers (Superphosphate and Ammonium sulphate) on the hatchability of Fasciola gigantica eggs. The results showed that hatchability decreased to 4% when eggs were incubated in bile secretion at 37 degrees C for 5 days and to 1.4% for 10 days, but few eggs incubated in water at 37 degrees C hatched. Bile secretion at 37 degrees C was a poor medium for in-vitro egg preservation. But, hatching occurred only when eggs were transferred to water at 26 degrees C. Temperature fluctuation from 26-4 degrees C or from 32-4 degrees C had an inhibitory effect on embryos development (35.2% & 32.3%, respectively) as compared to controls (60% & 63.9%, respectively). The incubation period (19 & 17 days) was higher than controls (14 & 12 days, respectively). The LC50 & LC90 of Copper sulphate and Niclosamide against Biomphalaria alexandrina and Lymnaea natalenesis had no toxic effect on Fasciola eggs. The higher concentrations of Copper sulphate (30 ppm) and Niclosamide (1 ppm) slightly lower eggs hatchability rate than controls. The rate decreased by increasing the exposure time from 3 to 6 hours with both molluscicides. Ammonium sulphate had a lethal effect on eggs, but Superphosphate had some inhibitory effect on egg development, which increased by increasing Superphosphate concentration or with the prolongation of the exposure time. PMID:18853633

  17. Testing the stress gradient hypothesis in herbivore communities facilitation peaks at intermediate nutrient levels.

    PubMed

    Bakker, Elisabeth S; Dobrescu, Ioana; Straile, Dietmar; Holmgren, Milena

    2013-08-01

    The role of positive interactions in structuring plant and animal communities is increasingly recognized, but the generality of current theoretical models has remained practically unexplored in animal communities. The stress gradient hypothesis predicts a linear increase in the intensity of facilitation as environmental conditions become increasingly stressful, whereas other theoretical models predict a maximum at intermediate environmental stress. We tested how competition and facilitation between herbivores change over a manipulated gradient of nutrient availability. We studied the effect of grazing by pond snails (Lymnaea stagnalis L.) as bulk grazers on aquatic caterpillars (Acentria ephemerella Denis and Schiffermüller) as small specialist grazers along an experimental gradient of environmental nutrient concentration. Higher nutrient levels increased overall total plant biomass but induced a shift toward dominance of filamentous algae at the expense of macrophytes. Facilitation of caterpillars by snail presence peaked at intermediate nutrient levels. Both caterpillar biomass and caterpillar grazing on macrophytes were highest at intermediate nutrient levels. Snails facilitated caterpillars possibly by removing filamentous algae and increasing access to the macrophyte resource, whereas they did not affect macrophyte biomass or C: nutrient ratios, a measure of food quality. We conclude that competition and facilitation in herbivore communities change along nutrient availability gradients that affect plant biomass and community composition. Understanding how interspecific interactions may change in strength and direction along environmental gradients is important to predict how the diversity and structure of communities may respond to the introduction or removal of herbivore species in ecosystems. PMID:24015521

  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. Thermotolerance induced by heat and ethanol.

    PubMed

    Boon-Niermeijer, E K; Souren, J E; De Waal, A M; Van Wijk, R

    1988-01-01

    The effect of ethanol and heat on the thermosensitivity of 3-day-old larvae of the fresh water snail Lymnaea stagnalis is investigated, especially with regard to the kinetics of thermotolerance, the effect on protein synthesis and the pattern of proteins synthesized. Both stress factors, in a mild dose, induce a state of thermotolerance with the following characteristics: (i) it is not accompanied by an enhanced synthesis of HSPs, (ii) it needs only 10-30 min to develop maximally, and (iii) it decays within 60-90 min after it has been triggered. At a higher dose both factors induce an enhanced synthesis of the HSP 65, HSP 70, and HSP 87, and also a more stable state of thermotolerance beside the thermotolerant state present shortly after the trigger. It appears that the synthesis of HSPs is enhanced only when the overall protein synthesis is depressed. The data are discussed in relation to the putative functions of heat shock proteins. It is suggested that the constitutive levels of the HSPs provide the rapid protection against heat. An induced level of HSPs is necessary for the extension of the thermotolerant state. PMID:3361168

  20. 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.

  1. Energetic endpoints provide early indicators of life history effects in a freshwater gastropod exposed to the fungicide, pyraclostrobin.

    PubMed

    Fidder, Bridgette N; Reátegui-Zirena, Evelyn G; Olson, Adric D; Salice, Christopher J

    2016-04-01

    Organismal energetics provide important insights into the effects of environmental toxicants. We aimed to determine the effects of pyraclostrobin on Lymnaea stagnalis by examining energy allocation patterns and life history traits. Juvenile snails exposed to pyraclostrobin decreased feeding rate and increased apparent avoidance behaviors at environmentally relevant concentrations. In adults, we found that sublethal concentrations of pyraclostrobin did not affect reproductive output, however, there were significant effects on developmental endpoints with longer time to hatch and decreased hatching success in pyraclostrobin-exposed egg masses. Further, there were apparent differences in developmental effects depending on whether mothers were also exposed to pyraclostrobin suggesting this chemical can exert intergenerational effects. Pyraclostrobin also affected protein and carbohydrate content of eggs in mothers that were exposed to pyraclostrobin. Significant effects on macronutrient content of eggs occurred at lower concentrations than effects on gross endpoints such as hatching success and time to hatch suggesting potential value for these endpoints as early indicators of ecologically relevant stress. These results provide important insight into the effects of a common fungicide on important endpoints for organismal energetics and life history. PMID:26766536

  2. 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

  3. 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

  4. 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.

  5. 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

  6. Molluscicidal activity of Punica granatum bark and Canna indica root.

    PubMed

    Tripathi, S M; Singh, D K

    2000-11-01

    The molluscicidal activity of Punica granatum Linn. (Punicaceae) and Canna indica Linn. (Cannaceae) against the snail Lymnaea acuminata was studied. The molluscicidal activity of P. granatum bark and C. indica root was found to be both time and dose dependent. The toxicity of P. granatum bark was more pronounced than that of C. indica. The 24 h LC(50) of the column-purified root of C. indica was 6.54 mg/l whereas that of the column-purified bark of P. granatum was 4.39 mg/l. The ethanol extract of P. granatum (24 h LC(50): 22.42 mg/l) was more effective than the ethanol extract of C. indica (24 h LC(50): 55.65 mg/l) in killing the test animals. P. granatum and C. indica may be used as potent molluscicides since the concentrations used to kill the snails were not toxic for the fish Colisa fasciatus, which shares the same habitat with the snail L. acuminata. PMID:11050667

  7. A multichannel native fluorescence detection system for capillary electrophoretic analysis of neurotransmitters in single neurons.

    PubMed

    Lapainis, T; Scanlan, C; Rubakhin, S S; Sweedler, J V

    2007-01-01

    A laser-induced native fluorescence detection system optimized for analysis of indolamines and catecholamines by capillary electrophoresis is described. A hollow-cathode metal vapor laser emitting at 224 nm is used for fluorescence excitation, and the emitted fluorescence is spectrally distributed by a series of dichroic beam-splitters into three wavelength channels: 250-310 nm, 310-400 nm, and >400 nm. A separate photomultiplier tube is used for detection of the fluorescence in each of the three wavelength ranges. The instrument provides more information than a single-channel system, without the complexity associated with a spectrograph/charge-coupled device-based detector. With this instrument, analytes can be separated and identified not only on the basis of their electrophoretic migration time but also on the basis of their multichannel signature, which consists of the ratios of relative fluorescence intensities detected in each wavelength channel. The 224-nm excitation channel resulted in a detection limit of 40 nmol L-1 for dopamine. The utility of this instrument for single-cell analysis was demonstrated by the detection and identification of the neurotransmitters in serotonergic LPeD1 and dopaminergic RPeD1 neurons, isolated from the central nervous system of the well-established neurobiological model Lymnaea stagnalis. Not only can this system detect neurotransmitters in these individual neurons with S/N>50, but analyte identity is confirmed on the basis of spectral characteristics. PMID:17047942

  8. 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

  9. 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.

  10. 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.

  11. 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. PMID:26747374

  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. PMID:27041341

  13. 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

  14. 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.

  15. Multi-neuronal refractory period adapts centrally generated behaviour to reward.

    PubMed

    Harris, Christopher A; Buckley, Christopher L; Nowotny, Thomas; Passaro, Peter A; Seth, Anil K; Kemenes, György; O'Shea, Michael

    2012-01-01

    Oscillating neuronal circuits, known as central pattern generators (CPGs), are responsible for generating rhythmic behaviours such as walking, breathing and chewing. The CPG model alone however does not account for the ability of animals to adapt their future behaviour to changes in the sensory environment that signal reward. Here, using multi-electrode array (MEA) recording in an established experimental model of centrally generated rhythmic behaviour we show that the feeding CPG of Lymnaea stagnalis is itself associated with another, and hitherto unidentified, oscillating neuronal population. This extra-CPG oscillator is characterised by high population-wide activity alternating with population-wide quiescence. During the quiescent periods the CPG is refractory to activation by food-associated stimuli. Furthermore, the duration of the refractory period predicts the timing of the next activation of the CPG, which may be minutes into the future. Rewarding food stimuli and dopamine accelerate the frequency of the extra-CPG oscillator and reduce the duration of its quiescent periods. These findings indicate that dopamine adapts future feeding behaviour to the availability of food by significantly reducing the refractory period of the brain's feeding circuitry. PMID:22860134

  16. Estimating Genetic and Maternal Effects Determining Variation in Immune Function of a Mixed-Mating Snail.

    PubMed

    Seppälä, Otto; Langeloh, Laura

    2016-01-01

    Evolution of host defenses such as immune function requires heritable genetic variation in them. However, also non-genetic maternal effects can contribute to phenotypic variation, thus being an alternative target for natural selection. We investigated the role of individuals' genetic background and maternal effects in determining immune defense traits (phenoloxidase and antibacterial activity of hemolymph), as well as in survival and growth, in the simultaneously hermaphroditic snail Lymnaea stagnalis. We utilized the mixed mating system of this species by producing full-sib families in which each parental snail had produced offspring as both a dam and as a sire, and tested whether genetic background (family) and non-genetic maternal effects (dam nested within family) explain trait variation. Immune defense traits and growth were affected solely by individuals' genetic background. Survival of snails did not show family-level variation. Additionally, some snails were produced through self-fertilization. They showed reduced growth and survival suggesting recessive load or overdominance. Immune defense traits did not respond to inbreeding. Our results suggest that the variation in snail immune function and growth was due to genetic differences. Since immune traits did not respond to inbreeding, this variation is most likely due to additive or epistatic genetic variance. PMID:27551822

  17. Acetylcholine binding protein of mollusks is unlikely to act as a regulator of cholinergic neurotransmission at neurite-neurite synaptic sites in vivo.

    PubMed

    Banks, Gareth; Kemenes, Ildiko; Schofield, Michael; O'Shea, Michael; Korneev, Sergei A

    2009-09-01

    A population of glial cells in the central nervous system of the gastropod mollusk Lymnaea stagnalis produces a soluble protein that specifically binds acetylcholine. This protein is named the acetylcholine binding protein (AChBP). Experiments performed in vitro indicated that AChBP inactivates released acetylcholine at cholinergic synapses. On the basis of these observations, a similar in vivo role for AChBP was hypothesized. To fulfill this function, AChBP-expressing glia ought to be located in close proximity to cholinergic synapses in vivo. To examine this, we have analyzed the cellular and subcellular expression of AChBP in the intact CNS. Using a variety of molecular techniques, we demonstrate here that AChBP expression is confined to a subpopulation of glial cells located within the peripheral zone of each of the ganglia constituting the CNS. This zone contains the cell bodies of neurons, but few synapses. Conversely, glial cells that do not express the AChBP are predominantly located in the synapse-rich central neuropile zone but are rare in the cell body zone. Thus, our findings are not compatible with the previous conclusions drawn from in vitro studies and suggest that AChBP functions in vivo as a regulator of nonsynaptic cholinergic transmission. PMID:19395478

  18. Revealing the secret lives of cryptic species: Examining the phylogenetic relationships of echinostome parasites in North America.

    PubMed

    Detwiler, Jillian T; Bos, David H; Minchella, Dennis J

    2010-05-01

    The recognition of cryptic parasite species has implications for evolutionary and population-based studies of wildlife and human disease. Echinostome trematodes are a widely distributed, species-rich group of internal parasites that infect a wide array of hosts and are agents of disease in amphibians, mammals, and birds. We utilize genetic markers to understand patterns of morphology, host use, and geographic distribution among several species groups. Parasites from >150 infected host snails (Lymnaea elodes, Helisoma trivolvis and Biomphalaria glabrata) were sequenced at two mitochondrial genes (ND1 and CO1) and one nuclear gene (ITS) to determine whether cryptic species were present at five sites in North and South America. Phylogenetic and network analysis demonstrated the presence of five cryptic Echinostoma lineages, one Hypoderaeum lineage, and three Echinoparyphium lineages. Cryptic life history patterns were observed in two species groups, Echinostoma revolutum and Echinostoma robustum, which utilized both lymnaied and planorbid snail species as first intermediate hosts. Molecular evidence confirms that two species, E. revolutum and E. robustum, have cosmopolitan distributions while other species, E. trivolvis and Echinoparyphium spp., may be more geographically limited. The intra and interspecific variation detected in our study provides a genetic basis for seven species groups of echinostomes which will help accurately identify agents of disease as well as reveal cryptic aspects of trematode biology. PMID:20064622

  19. 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

  20. Modeling spatial frailties in survival analysis of cucurbit downy mildew epidemics.

    PubMed

    Ojiambo, P S; Kang, E L

    2013-03-01

    Cucurbit downy mildew caused by Pseudoperonospora cubensis is economically the most important disease of cucurbits globally, and the pathogen is disseminated aerially over a large spatial scale. Spatio-temporal spread of the disease was characterized during phase I (low and sporadic disease outbreaks) and II (rapid increase in disease outbreaks) of the epidemic using records collected from sentinel plots from 2008 to 2009 in 23 states in the eastern United States as part of the United States Department of Agriculture Cucurbit Downy Mildew ipmPIPE network. A substantive goal of this study was to explain the pattern of time to disease outbreak using important covariates while accounting for spatially correlated differences in risk of disease outbreak among the states. Survival analyses that accounts for spatial dependence were performed on time to disease outbreak, and posterior median frailties (or random effects) were mapped to identify states with high or low risk for disease outbreak. From February to October, disease occurred in 195 and 172 out of 413 and 556 cases monitored in 2008 and 2009, respectively. Disease outbreaks were spatially aggregated, with a spatial dependence of up to ≈1,025 km where clustering of outbreaks in phase I and II of the epidemic were similar. However, unlike in phase I of the epidemic, space-time point pattern analysis was significant (P < 0.0001) for outbreaks in phase II, during which the highest risk window as estimated by the space-time function was within 1.5 months and 500 km of the initial outbreak. The risk of disease outbreak peaked around July and decreased thereafter until the end of the study period. Spatially correlated analysis of time to disease outbreak indicated the need to incorporate spatial frailties in standard survival analysis models. Evaluation of alternative formulations of the spatial models demonstrated that a Bayesian hierarchical spatially structured frailty model best described time to disease outbreak

  1. Allelopathic potential and ecotoxicity evaluation of gallic and nonanoic acids to prevent cyanobacterial growth in lentic systems: A preliminary mesocosm study.

    PubMed

    Techer, Didier; Fontaine, Pascal; Personne, Aline; Viot, Sandrine; Thomas, Marielle

    2016-03-15

    The increase in anthropogenic nutrient loading affecting many freshwater ecosystems combined with global warming may lead to cyanobacterial blooms on an increasingly frequent basis. Among the various physicochemical and biological methods which have been proposed to rapidly control blue-green algae growth, the use of plant-derived substances such as allelochemicals has gained great interest as an environment-friendly approach. The primary aim of this work was to evaluate the efficiency of gallic and nonanoic acid application to preemptively inhibit cyanobacterial growth in lentic hydrosystems. In order to address the process feasibility under realistic exposure scenarios, thirteen outdoor freshwater mesocosms (unit volume: 3m(3)) were designed, each containing phytoplankton (including local blue-green algae species) and various non-target organisms from higher trophic levels (Physa, Lymnaea, Gammarus, and Scardinius erythrophthalmus). After an 8-week mesocosm stabilization period, a full factorial design based on the presence/absence of gallic acid (GA) and nonanoic acid (NA) (including a control group) was implemented into the exposure tanks. Regular monitoring of major phytoplankton taxa was conducted during a 28-day experiment using an on-line fluorometer. The main results suggested that gallic acid was more efficient than nonanoic acid at limiting cyanobacterial growth at concentrations as low as 1 mg L(-1). Successive gallic acid applications (at 1, 2 and 4 mg L(-1)) at the early stages of cyanobacterial growth did not allow the complete elimination of blue-green algae from the mesocosms. However, the specificity of the allelopathic effect of gallic acid towards cyanobacteria was compatible with the maintenance of a primary productivity in the treated tanks as indicated by the photoautotrophic growth of other algal taxa. Finally, no biomarker induction signal could be reported in non-target species. Further gallic acid application trials in lentic systems such

  2. Roles of G-protein beta gamma, arachidonic acid, and phosphorylation inconvergent activation of an S-like potassium conductance by dopamine, Ala-Pro-Gly-Trp-NH2, and Phe-Met-Arg-Phe-NH2.

    PubMed

    van Tol-Steye, H; Lodder, J C; Mansvelder, H D; Planta, R J; van Heerikhuizen, H; Kits, K S

    1999-05-15

    Dopamine and the neuropeptides Ala-Pro-Gly-Trp-NH2 (APGWamide or APGWa) and Phe-Met-Arg-Phe-NH2 (FMRFamide or FMRFa) all activate an S-like potassium channel in the light green cells of the mollusc Lymnaea stagnalis, neuroendocrine cells that release insulin-related peptides. We studied the signaling pathways underlying the responses, the role of the G-protein betagamma subunit, and the interference by phosphorylation pathways. All responses are blocked by an inhibitor of arachidonic acid (AA) release, 4-bromophenacylbromide, and by inhibitors of lipoxygenases (nordihydroguaiaretic acid and AA-861) but not by indomethacin, a cyclooxygenase inhibitor. AA and phospholipase A2 (PLA2) induced currents with similar I-V characteristics and potassium selectivity as dopamine, APGWa, and FMRFa. PLA2 occluded the response to FMRFa. We conclude that convergence of the actions of dopamine, APGWa, and FMRFa onto the S-like channel occurs at or upstream of the level of AA and that formation of lipoxygenase metabolites of AA is necessary to activate the channel. Injection of a synthetic peptide, which interferes with G-protein betagamma subunits, inhibited the agonist-induced potassium current. This suggests that betagamma subunits mediate the response, possibly by directly coupling to a phospholipase. Finally, the responses to dopamine, APGWa, and FMRFa were inhibited by activation of PKA and PKC, suggesting that the responses are counteracted by PKA- and PKC-dependent phosphorylation. The PLA2-activated potassium current was inhibited by 8-chlorophenylthio-cAMP but not by 12-O-tetradecanoylphorbol 13-acetate (TPA). However, TPA did inhibit the potassium current induced by irreversible activation of the G-protein using GTP-gamma-S. Thus, it appears that PKA targets a site downstream of AA formation, e.g., the potassium channel, whereas PKC acts at the active G-protein or the phospholipase. PMID:10234006

  3. [The fate of subspecies category in zoological systematics. 2. The present].

    PubMed

    Vinarski, M V

    2015-01-01

    The present approach to the use of subspecies category in zoological systematics is an integrative one. It counts as obligatory to confirm the validity of subspecies, defined by morphological data, with genetic criteria. This allows marking out those subspecies that really exist as separate monophyletic population groups. As a result, the system would be cleared of many 'phantom' taxa established in course of non-critical use of the subspecies concept. However, detailed analyses of intra-species variability by methods of molecular taxonomy in many cases reveal a quite complicated divergence pattern which cannot be adequately described in terms of the classic scheme of 'species and its subspecies'. Keeping in mind the irregularity of intra-species divergence rate when dealing with molecular and morphological traits, it is proposed to use an extended system of subspecies taxa when describing 'extra complicated' situations. In addition to a 'subspecies' such categories as 'allospecies', 'morphotype', 'morphospecies' may be used for which operational definitions are suggested. As an example, the micro-systematics of the great pond snails (the complex Lymnaea stagnalis s. lato) from Palaearctic region is examined. The provisional system of this group, developed by the author, is based on morphological and phylogeographical data. Applying the series of subspecies categories of different level allows reflecting with maximal completeness the intra-species variability of great pond snails and, to some extent, the process of their genetic divergence and geographic range forming. The second part of the article deals with modern approaches to subspecies category usage in zoological systematics as well as the problems of so called micro-systematics, i.e., systematics operating at the lowest level of categories such as ones of subspecies and infra-subspecies rank (Mayr, 1982). PMID:25985485

  4. Structural basis for cooperative interactions of substituted 2-aminopyrimidines with the acetylcholine binding protein

    PubMed Central

    Kaczanowska, Katarzyna; Harel, Michal; Radić, Zoran; Changeux, Jean-Pierre; Finn, M. G.; Taylor, Palmer

    2014-01-01

    The nicotinic acetylcholine receptor (nAChR) and the acetylcholine binding protein (AChBP) are pentameric oligomers in which binding sites for nicotinic agonists and competitive antagonists are found at selected subunit interfaces. The nAChR spontaneously exists in multiple conformations associated with its activation and desensitization steps, and conformations are selectively stabilized by binding of agonists and antagonists. In the nAChR, agonist binding and the associated conformational changes accompanying activation and desensitization are cooperative. AChBP, which lacks the transmembrane spanning and cytoplasmic domains, serves as a homology model of the extracellular domain of the nAChRs. We identified unique cooperative binding behavior of a number of 4,6-disubstituted 2-aminopyrimidines to Lymnaea AChBP, with different molecular variants exhibiting positive, nH > 1.0, and negative cooperativity, nH < 1.0. Therefore, for a distinctive set of ligands, the extracellular domain of a nAChR surrogate suffices to accommodate cooperative interactions. X-ray crystal structures of AChBP complexes with examples of each allowed the identification of structural features in the ligands that confer differences in cooperative behavior. Both sets of molecules bind at the agonist-antagonist site, as expected from their competition with epibatidine. An analysis of AChBP quaternary structure shows that cooperative ligand binding is associated with a blooming or flare conformation, a structural change not observed with the classical, noncooperative, nicotinic ligands. Positively and negatively cooperative ligands exhibited unique features in the detailed binding determinants and poses of the complexes. PMID:25006260

  5. Structural basis for cooperative interactions of substituted 2-aminopyrimidines with the acetylcholine binding protein.

    PubMed

    Kaczanowska, Katarzyna; Harel, Michal; Radić, Zoran; Changeux, Jean-Pierre; Finn, M G; Taylor, Palmer

    2014-07-22

    The nicotinic acetylcholine receptor (nAChR) and the acetylcholine binding protein (AChBP) are pentameric oligomers in which binding sites for nicotinic agonists and competitive antagonists are found at selected subunit interfaces. The nAChR spontaneously exists in multiple conformations associated with its activation and desensitization steps, and conformations are selectively stabilized by binding of agonists and antagonists. In the nAChR, agonist binding and the associated conformational changes accompanying activation and desensitization are cooperative. AChBP, which lacks the transmembrane spanning and cytoplasmic domains, serves as a homology model of the extracellular domain of the nAChRs. We identified unique cooperative binding behavior of a number of 4,6-disubstituted 2-aminopyrimidines to Lymnaea AChBP, with different molecular variants exhibiting positive, nH > 1.0, and negative cooperativity, nH < 1.0. Therefore, for a distinctive set of ligands, the extracellular domain of a nAChR surrogate suffices to accommodate cooperative interactions. X-ray crystal structures of AChBP complexes with examples of each allowed the identification of structural features in the ligands that confer differences in cooperative behavior. Both sets of molecules bind at the agonist-antagonist site, as expected from their competition with epibatidine. An analysis of AChBP quaternary structure shows that cooperative ligand binding is associated with a blooming or flare conformation, a structural change not observed with the classical, noncooperative, nicotinic ligands. Positively and negatively cooperative ligands exhibited unique features in the detailed binding determinants and poses of the complexes. PMID:25006260

  6. Virtual Screening Against α-Cobratoxin

    PubMed Central

    UTSINTONG, MALEERUK; TALLEY, TODD T.; TAYLOR, PALMER W.; OLSON, ARTHUR J.; VAJRAGUPTA, OPA

    2011-01-01

    α-Cobratoxin (Cbtx), the neurotoxin isolated from the venom of the Thai cobra Naja kaouthia, causes paralysis by preventing acetylcholine (ACh) binding to nicotinic acetylcholine receptors (nAChRs). In the current study, the region of the Cbtx molecule that is directly involved in binding to nAChRs is used as the target for anticobratoxin drug design. The crystal structure (1YI5) of Cbtx in complex with the acetylcholine binding protein (AChBP), a soluble homolog of the extracellular binding domain of nAChRs, was selected to prepare an α-cobratoxin active binding site for docking. The amino acid residues (Ser182-Tyr192) of the AChBP structure, the binding site of Cbtx, were used as the positive control to validate the prepared Cbtx active binding site (root mean square deviation < 1.2 Å). Virtual screening of the National Cancer Institute diversity set, a library of 1990 compounds with nonredundant pharmacophore profiles, using AutoDock against the Cbtx active site, revealed 39 potential inhibitor candidates. The adapted in vitro radioligand competition assays using [3H]epibatidine and [125I]bungarotoxin against the AChBPs from the marine species, Aplysia californica (Ac), and from the freshwater snails, Lymnaea stagnalis (Ls) and Bolinus truncates (Bt), revealed 4 compounds from the list of inhibitor candidates that had micromolar to nanomolar interferences for the toxin binding to AChBPs. Three hits (NSC42258, NSC121865, and NSC134754) can prolong the survival time of the mice if administered 30 min before injection with Cbtx, but only NSC121865 and NSC134754 can prolong the survival time if injected immediately after injection with Cbtx. These inhibitors serve as novel templates/scaffolds for the development of more potent and specific anticobratoxin. PMID:19734437

  7. Triassic and Jurassic rocks at Currie, Nevada Preliminary paleontologic evidence

    SciTech Connect

    Johnson, E.A.; Dubiel, R.F.; Brouwers, E.M. ); Litwin, R.J. ); Ash, S.R. ); Good, S.C. )

    1993-04-01

    A sequence of continental rocks overlies the Lower Triassic Thaynes Formation in a poorly exposed syncline near Currie in northeastern NV. The authors recognize four lithostratigraphic units above the Thaynes near Currie and provide new paleontologic data. In ascending order, unit 1 (120 ft) consists of reddish-brown, very fine grained sandstone. Unit 2 (50 ft) consists of light-gray, trough cross-stratified, coarse-grained, conglomeratic sandstone. Unit 3 (at least 500 ft) consists of green, red, and brown sandstone and mudstone. Unit 4 occurs as isolated outcrops of reddish-orange, fine- to medium-grained sandstone. New fossil evidence, while not definitive, constrain the age of this sequence. Plant megafossils in unit 1 include (1) a specimen with narrow ovate leaves, possibly from an early Mesozoic conifer and (2) abundant fragments of probable Neocalamites. The presence of these fossils and the absence of any angiosperm leaves or wood fragments suggest an early Mesozoic age. Ostracodes in unit 3 are exclusively Darwinula sp., and their association with conchostracans in the absence of younger ostracodes suggests a Triassic age. Finally, two small outcrops, previously mapped as Triassic/Jurassic, contain the gastropods Pilidae indet. and Lymnaea sp., which resemble Late Cretaceous to Paleocene faunas. The sequence is similar to the nearest Lower Mesozoic section on the Colorado Plateau at Cove Fort, Utah, 165 miles to the southeast. The authors' new evidence supports the longstanding correlation of units 1--4 with the Lower Triassic Moenkopi Formation (part), the Shinarump and Petrified Forest Members of the Upper Triassic Chinle Formation, and the Lower Jurassic Navajo Sandstone of the Plateau. These rocks at Currie demonstrate that the Early Mesozoic depositional systems of the Colorado Plateau extended at least this far west and provide constraints on Early Mesozoic tectonism in the eastern Great Basin.

  8. Docking studies of benzylidene anabaseine interactions with α7 nicotinic acetylcholine receptor (nAChR) and acetylcholine binding proteins (AChBPs): Application to the design of related α7 selective ligands

    PubMed Central

    Kombo, David C.; Mazurov, Anatoly; Tallapragada, Kartik; Hammond, Philip S.; Chewning, Joseph; Hauser, Terry A.; Vasquez-Valdivieso, Montserrat; Yohannes, Daniel; Talley, Todd T.; Taylor, Palmer; Caldwell, William S.

    2016-01-01

    AChBPs isolated from Lymnaea stagnalis (Ls), Aplysia californica (Ac) and Bulinus truncatus (Bt) have been extensively used as structural prototypes to understand the molecular mechanisms that underlie ligand-interactions with nAChRs [1]. Here, we describe docking studies on interactions of benzylidene anabaseine analogs with AChBPs and α7 nAChR. Results reveal that docking of these compounds using Glide software accurately reproduces experimentally-observed binding modes of DMXBA and of its active metabolite, in the binding pocket of Ac. In addition to the well-known nicotinic pharmacophore (positive charge, hydrogen-bond acceptor, and hydrophobic aromatic groups), a hydrogen-bond donor feature contributes to binding of these compounds to Ac, Bt, and the α7 nAChR. This is consistent with benzylidene anabaseine analogs with OH and NH2 functional groups showing the highest binding affinity of these congeners, and the position of the ligand shown in previous X-ray crystallographic studies of ligand-Ac complexes. In the predicted ligand-Ls complex, by contrast, the ligand OH group acts as hydrogen-bond acceptor. We have applied our structural findings to optimizing the design of novel spirodiazepine and spiroimidazoline quinuclidine series. Binding and functional studies revealed that these hydrogen-bond donor containing compounds exhibit improved affinity and selectivity for the α7 nAChR subtype and demonstrate partial agonism. The gain in affinity is also due to conformational restriction, tighter hydrophobic enclosures, and stronger cation-π interactions. The use of AChBPs structure as a surrogate to predict binding affinity to α7 nAChR has also been investigated. On the whole, we found that molecular docking into Ls binding site generally scores better than when a α7 homology model, Bt or Ac crystal structure is used. PMID:21986237

  9. Experimental life history and biological characteristics of Fasciola gigantica (Digenea: Fasciolidae).

    PubMed

    Phalee, Anawat; Wongsawad, Chalobol; Rojanapaibul, Amnat; Chai, Jong-Yil

    2015-02-01

    This study was conducted to investigate the life history, morphology, and maturation of larval stages and adult worms of Fasciola gigantica in experimental mice. Lymnaea auricularia rubiginosa was used as the intermediate host, and Oryza sativa was used for encystment of the metacercariae, while Mus musculus was used as the definitive host for maturation study. Fresh eggs from the gall bladder of water buffaloes fully developed into embryonated ones and hatched out at days 11-12 after incubation at about 29ºC. Free-swimming miracidia rapidly penetrated into the snail host, and gradually developed into the next larval stages; sporocyst, redia, and daughter redia with cercariae. Fully-developed cercariae were separated from the redia and shed from the snails on day 39 post-infection (PI). Free-swimming cercariae were immediately allowed to adhere to rice plants, and capsules were constructed to protect metacercariae on rice plants. Juvenile worms were detected in intestines of mice at days 3 and 6 PI, but they were found in the bile duct from day 9 PI. Juvenile and adult flukes were recovered from 16 mice experimentally infected with metacercariae, with the average recovery rate of 35.8%. Sexually mature adult flukes were recovered from day 42 PI. It could be confirmed that experimentally encysted metacercariae could infect and develop to maturity in the experimental host. The present study reports for the first time the complete life history of F. gigantica by an experimental study in Thailand. The obtained information can be used as a guide for prevention, elimination, and treatment of F. gigantica at environment and in other hosts. PMID:25748710

  10. Habitat characteristics for different freshwater snail species as determined biologically through macroinvertebrate information.

    PubMed

    El-Khayat, Hanaa M M; Mahmoud, Kadria M A; Mostafa, Bayomy B; Tantawy, Ahmad A; El-Deeb, Fatma A; Ragb, Fawzy M; Ismail, Nahed M; El-Said, Kalil M; Taleb, Hoda M Abu

    2011-12-01

    Macro-invertebrates including freshwater snails collected from 643 sites over 8 successive seasons among the River Nile, branches, main canals and certain drains in eight Egyptian Governorates. Thirteen snail species and one bivalve species were identified. The most distributed were Lanistus carinatus and Physa acuta while the most abundant were Cleopatra bulimoides and Physa acuta during the whole study. The sites that harbored each snail species in all the examined water-courses were grouped seasonally and their biological assessment was determined by their minimum and maximum total point similarity percentage to that of the corresponded reference site and mean of the total points. Habitats for most snail species attained minimum total point's similarity percentage less than 21% (very poor habitat) during autumn and winter then spring while during summer very poor habitat was harbored by only few snail species. P. acuta was the only survived snails in habitat which attained 0 as a minimum total point's similarity percentage during two seasons and L. carinatus and Succinea cleopatra during one season. With respect to medically important snails very poor sites constituted 23% of Biomphalaria alexandrina sites, 14% of Lymnaea natalensis and 9.4% of Bulinus truncatus sites. The studied macroinvertebrate matrices, total number of organisms, taxa richness, the Ephemeroptera, Plecoptera, and Trichoptera (EPT) index, ratio of EPT index to chironomidae, ratio of scraper to filtering collector, contribution of dominant macroinvertebrate major group, comparison revealed descending tolerances from B. alexanrina followed by L. natalensis then B. truncates, but Hilsenhoff Biotic Index (HBI) showed the same tolerance to organic pollution. PMID:22435158

  11. Interneuronal mechanism for Tinbergen's hierarchical model of behavioral choice.

    PubMed

    Pirger, Zsolt; Crossley, Michael; László, Zita; Naskar, Souvik; Kemenes, György; O'Shea, Michael; Benjamin, Paul R; Kemenes, Ildikó

    2014-09-01

    Recent studies of behavioral choice support the notion that the decision to carry out one behavior rather than another depends on the reconfiguration of shared interneuronal networks [1]. We investigated another decision-making strategy, derived from the classical ethological literature [2, 3], which proposes that behavioral choice depends on competition between autonomous networks. According to this model, behavioral choice depends on inhibitory interactions between incompatible hierarchically organized behaviors. We provide evidence for this by investigating the interneuronal mechanisms mediating behavioral choice between two autonomous circuits that underlie whole-body withdrawal [4, 5] and feeding [6] in the pond snail Lymnaea. Whole-body withdrawal is a defensive reflex that is initiated by tactile contact with predators. As predicted by the hierarchical model, tactile stimuli that evoke whole-body withdrawal responses also inhibit ongoing feeding in the presence of feeding stimuli. By recording neurons from the feeding and withdrawal networks, we found no direct synaptic connections between the interneuronal and motoneuronal elements that generate the two behaviors. Instead, we discovered that behavioral choice depends on the interaction between two unique types of interneurons with asymmetrical synaptic connectivity that allows withdrawal to override feeding. One type of interneuron, the Pleuro-Buccal (PlB), is an extrinsic modulatory neuron of the feeding network that completely inhibits feeding when excited by touch-induced monosynaptic input from the second type of interneuron, Pedal-Dorsal12 (PeD12). PeD12 plays a critical role in behavioral choice by providing a synaptic pathway joining the two behavioral networks that underlies the competitive dominance of whole-body withdrawal over feeding. PMID:25155505

  12. Predicting impacts of climate change on Fasciola hepatica risk.

    PubMed

    Fox, Naomi J; White, Piran C L; McClean, Colin J; Marion, Glenn; Evans, Andy; Hutchings, Michael R

    2011-01-01

    Fasciola hepatica (liver fluke) is a physically and economically devastating parasitic trematode whose rise in recent years has been attributed to climate change. Climate has an impact on the free-living stages of the parasite and its intermediate host Lymnaea truncatula, with the interactions between rainfall and temperature having the greatest influence on transmission efficacy. There have been a number of short term climate driven forecasts developed to predict the following season's infection risk, with the Ollerenshaw index being the most widely used. Through the synthesis of a modified Ollerenshaw index with the UKCP09 fine scale climate projection data we have developed long term seasonal risk forecasts up to 2070 at a 25 km square resolution. Additionally UKCIP gridded datasets at 5 km square resolution from 1970-2006 were used to highlight the climate-driven increase to date. The maps show unprecedented levels of future fasciolosis risk in parts of the UK, with risk of serious epidemics in Wales by 2050. The seasonal risk maps demonstrate the possible change in the timing of disease outbreaks due to increased risk from overwintering larvae. Despite an overall long term increase in all regions of the UK, spatio-temporal variation in risk levels is expected. Infection risk will reduce in some areas and fluctuate greatly in others with a predicted decrease in summer infection for parts of the UK due to restricted water availability. This forecast is the first approximation of the potential impacts of climate change on fasciolosis risk in the UK. It can be used as a basis for indicating where active disease surveillance should be targeted and where the development of improved mitigation or adaptation measures is likely to bring the greatest benefits. PMID:21249228

  13. The Calmodulin-Binding, Short Linear Motif, NSCaTE Is Conserved in L-Type Channel Ancestors of Vertebrate Cav1.2 and Cav1.3 Channels

    PubMed Central

    Taiakina, Valentina; Boone, Adrienne N.; Fux, Julia; Senatore, Adriano; Weber-Adrian, Danielle

    2013-01-01

    NSCaTE is a short linear motif of (xWxxx(I or L)xxxx), composed of residues with a high helix-forming propensity within a mostly disordered N-terminus that is conserved in L-type calcium channels from protostome invertebrates to humans. NSCaTE is an optional, lower affinity and calcium-sensitive binding site for calmodulin (CaM) which competes for CaM binding with a more ancient, C-terminal IQ domain on L-type channels. CaM bound to N- and C- terminal tails serve as dual detectors to changing intracellular Ca2+ concentrations, promoting calcium-dependent inactivation of L-type calcium channels. NSCaTE is absent in some arthropod species, and is also lacking in vertebrate L-type isoforms, Cav1.1 and Cav1.4 channels. The pervasiveness of a methionine just downstream from NSCaTE suggests that L-type channels could generate alternative N-termini lacking NSCaTE through the choice of translational start sites. Long N-terminus with an NSCaTE motif in L-type calcium channel homolog LCav1 from pond snail Lymnaea stagnalis has a faster calcium-dependent inactivation than a shortened N-termini lacking NSCaTE. NSCaTE effects are present in low concentrations of internal buffer (0.5 mM EGTA), but disappears in high buffer conditions (10 mM EGTA). Snail and mammalian NSCaTE have an alpha-helical propensity upon binding Ca2+-CaM and can saturate both CaM N-terminal and C-terminal domains in the absence of a competing IQ motif. NSCaTE evolved in ancestors of the first animals with internal organs for promoting a more rapid, calcium-sensitive inactivation of L-type channels. PMID:23626724

  14. The calmodulin-binding, short linear motif, NSCaTE is conserved in L-type channel ancestors of vertebrate Cav1.2 and Cav1.3 channels.

    PubMed

    Taiakina, Valentina; Boone, Adrienne N; Fux, Julia; Senatore, Adriano; Weber-Adrian, Danielle; Guillemette, J Guy; Spafford, J David

    2013-01-01

    NSCaTE is a short linear motif of (xWxxx(I or L)xxxx), composed of residues with a high helix-forming propensity within a mostly disordered N-terminus that is conserved in L-type calcium channels from protostome invertebrates to humans. NSCaTE is an optional, lower affinity and calcium-sensitive binding site for calmodulin (CaM) which competes for CaM binding with a more ancient, C-terminal IQ domain on L-type channels. CaM bound to N- and C- terminal tails serve as dual detectors to changing intracellular Ca(2+) concentrations, promoting calcium-dependent inactivation of L-type calcium channels. NSCaTE is absent in some arthropod species, and is also lacking in vertebrate L-type isoforms, Cav1.1 and Cav1.4 channels. The pervasiveness of a methionine just downstream from NSCaTE suggests that L-type channels could generate alternative N-termini lacking NSCaTE through the choice of translational start sites. Long N-terminus with an NSCaTE motif in L-type calcium channel homolog LCav1 from pond snail Lymnaea stagnalis has a faster calcium-dependent inactivation than a shortened N-termini lacking NSCaTE. NSCaTE effects are present in low concentrations of internal buffer (0.5 mM EGTA), but disappears in high buffer conditions (10 mM EGTA). Snail and mammalian NSCaTE have an alpha-helical propensity upon binding Ca(2+)-CaM and can saturate both CaM N-terminal and C-terminal domains in the absence of a competing IQ motif. NSCaTE evolved in ancestors of the first animals with internal organs for promoting a more rapid, calcium-sensitive inactivation of L-type channels. PMID:23626724

  15. Biotic variation in coastal water bodies in Sussex, England: Implications for saline lagoons

    NASA Astrophysics Data System (ADS)

    Joyce, Chris B.; Vina-Herbon, Cristina; Metcalfe, Daniel J.

    2005-12-01

    Coastal water bodies are a heterogeneous resource typified by high spatial and temporal variability and threatened by anthropogenic impacts. This includes saline lagoons, which support a specialist biota and are a priority habitat for nature conservation. This paper describes the biotic variation in coastal water bodies in Sussex, England, in order to characterise the distinctiveness of the saline lagoon community and elucidate environmental factors that determine its distribution. Twenty-eight coastal water bodies were surveyed for their aquatic flora and invertebrate fauna and a suite of exploratory environmental variables compiled. Ordination and cluster analyses were used to examine patterns in community composition and relate these to environmental parameters. Biotic variation in the coastal water body resource was high. Salinity was the main environmental parameter explaining the regional distribution of taxa; freshwater and saline assemblages were evident and related to sea water ingress. Freshwater sites were indicated by the plant Myriophyllum spicatum and gastropod mollusc Lymnaea peregra, while more saline communities supported marine and brackish water taxa, notably a range of chlorophytic algae and the bivalve mollusc Cerastoderma glaucum. Site community differences were also related to bank slope and parameters describing habitat heterogeneity. A saline lagoon community was discerned within the matrix of biotic variation consisting of specialist lagoonal species with associated typically euryhaline taxa. For fauna, the latter were the molluscs Abra tenuis and Hydrobia ulvae, and the crustaceans Corophium volutator and Palaemonetes varians, and for flora they were the algae Ulva lactuca, Chaetomorpha mediterranea, Cladophora spp. and Enteromorpha intestinalis. One non-native polychaete species, Ficopomatus enigmaticus, also strongly influenced community structure within the lagoonal resource. The community was not well defined as specialist and

  16. Experimental Life History and Biological Characteristics of Fasciola gigantica (Digenea: Fasciolidae)

    PubMed Central

    Phalee, Anawat; Wongsawad, Chalobol; Rojanapaibul, Amnat; Chai, Jong-Yil

    2015-01-01

    This study was conducted to investigate the life history, morphology, and maturation of larval stages and adult worms of Fasciola gigantica in experimental mice. Lymnaea auricularia rubiginosa was used as the intermediate host, and Oryza sativa was used for encystment of the metacercariae, while Mus musculus was used as the definitive host for maturation study. Fresh eggs from the gall bladder of water buffaloes fully developed into embryonated ones and hatched out at days 11-12 after incubation at about 29ºC. Free-swimming miracidia rapidly penetrated into the snail host, and gradually developed into the next larval stages; sporocyst, redia, and daughter redia with cercariae. Fully-developed cercariae were separated from the redia and shed from the snails on day 39 post-infection (PI). Free-swimming cercariae were immediately allowed to adhere to rice plants, and capsules were constructed to protect metacercariae on rice plants. Juvenile worms were detected in intestines of mice at days 3 and 6 PI, but they were found in the bile duct from day 9 PI. Juvenile and adult flukes were recovered from 16 mice experimentally infected with metacercariae, with the average recovery rate of 35.8%. Sexually mature adult flukes were recovered from day 42 PI. It could be confirmed that experimentally encysted metacercariae could infect and develop to maturity in the experimental host. The present study reports for the first time the complete life history of F. gigantica by an experimental study in Thailand. The obtained information can be used as a guide for prevention, elimination, and treatment of F. gigantica at environment and in other hosts. PMID:25748710

  17. Unusual snail species involved in the transmission of Fasciola hepatica in watercress beds in central France.

    PubMed

    Dreyfuss, G; Vignoles, P; Abrous, M; Rondelaud, D

    2002-06-01

    Four freshwater pulmonate species (Lymnaea ovata, L. stagnalis, Physa acuta, Planorbis leucostoma) were living in several watercress beds known for their relationships with human cases of fasciolosis, whereas L. truncatula was never found. The aims of these studies were to determine the prevalence of natural infections with Fasciola hepatica in snails and to verify if these species might ensure the full larval development of this trematode (with cercarial shedding) when they were experimentally subjected to F. hepatica only, or to co-infections with an other trematode species. Investigations were so carried out in six snail populations living in watercress beds (including three for P. acuta) and in four others originating from three brooks or a pond (as controls). Snails naturally infected with F. hepatica were found in two watercress beds inhabited by L. ovata (prevalence of infection: 1.4%) and P. leucostoma (0.1%), respectively. The L. ovata from the watercress bed could be infected at a higher size than those from the control population and the prevalence of this infection was greater in the bed population. Similar findings were noted for L. stagnalis. Despite single or dual infections, the results obtained with the four populations of P. acuta were unsuccessful. In contrast, the co-infections of young P. leucostoma with Paramphistomum daubneyi and F. hepatica resulted in the shedding of some F. hepatica cercariae. According to the authors, the occurrence of fasciolosis in these watercress beds would be the consequence of frequent natural encounters between parasite and snails (L. ovata, L. stagnalis), or of co-infections with P. daubneyi and F. hepatica (P. leucostoma). In watercress beds only colonized by P. acuta, a lymnaeid species would have ensured the larval development of F. hepatica but it would have been eliminated by P. acuta, as this last species was known to be invasive and could colonize open drainage ditches on siliceous soil. PMID:12116856

  18. [About effect of habitat and motor activity of molluscs on fatty acid composition of triglycerides and phospholipids].

    PubMed

    Arakelova, E S; Chebotareva, M A; Zabelinskiĭ, S A; Ivanova, V P

    2009-01-01

    A comparative analysis of fatty acids (FA) in neutral and phospholipids of digestive gland and pedal muscle has been performed in molluscs from various ecological groups differing by belonging to sea or fresh water, trophic types or the associated motor activity. In freshwater pulmonary gastropods Lymnaea stagnalis and Limnaea ovalis and marine prosobranchial molluscs Buccinum undatum and Littorina littorea the total content of omega3-acids in phospholipids of the studied tissues differed more than twice, predominantly due to the combined effect of temperature and salinity of the habitat. The lower viscosity of cell membranes in marine species (omega3/omega6 < 1) is determined to the greatest degree by the presence of eicosapentaenoic acid that accounts for 22-25 % of the FA sum in marine species. Comparison of the molluscs by their trophic belonging has revealed the presence of linoleic acid in triglycerides in digestive glands of phytophages (8-12 %), but the practically complete absence of this acid in the predator B. undulatum (<0.8 %. By mobility, L. littorea inhabiting the high-low tide littoral was inferior to freshwater pulmonary gastropods and to marine predator, as it stops moving twice a day during the low tide. In phospholipids of pedal muscle of this mollusc the amount of long-chain polyunsaturated C:22 FA was 3-6 times lower than that in other studied species, which might possibly indicate the role of these acids in functioning of the pedal muscle contractile tissue. On the whole, use of the FA characteristics as parameters determining belonging to certain ecological group requires a certain caution due to a complex action of biotic and abiotic factors on the animal metabolism. The exception is the omega3/omega6 ratio in total phospholipids of freshwater and marine gastropods. PMID:19370988

  19. Marine Natural Products Acting on the Acetylcholine-Binding Protein and Nicotinic Receptors: From Computer Modeling to Binding Studies and Electrophysiology

    PubMed Central

    Kudryavtsev, Denis; Makarieva, Tatyana; Utkina, Natalia; Santalova, Elena; Kryukova, Elena; Methfessel, Christoph; Tsetlin, Victor; Stonik, Valentin; Kasheverov, Igor

    2014-01-01

    For a small library of natural products from marine sponges and ascidians, in silico docking to the Lymnaea stagnalis acetylcholine-binding protein (AChBP), a model for the ligand-binding domains of nicotinic acetylcholine receptors (nAChRs), was carried out and the possibility of complex formation was revealed. It was further experimentally confirmed via competition with radioiodinated α-bungarotoxin ([125I]-αBgt) for binding to AChBP of the majority of analyzed compounds. Alkaloids pibocin, varacin and makaluvamines С and G had relatively high affinities (Ki 0.5–1.3 μM). With the muscle-type nAChR from Torpedo californica ray and human neuronal α7 nAChR, heterologously expressed in the GH4C1 cell line, no competition with [125I]-αBgt was detected in four compounds, while the rest showed an inhibition. Makaluvamines (Ki ~ 1.5 μM) were the most active compounds, but only makaluvamine G and crambescidine 359 revealed a weak selectivity towards muscle-type nAChR. Rhizochalin, aglycone of rhizochalin, pibocin, makaluvamine G, monanchocidin, crambescidine 359 and aaptamine showed inhibitory activities in electrophysiology experiments on the mouse muscle and human α7 nAChRs, expressed in Xenopus laevis oocytes. Thus, our results confirm the utility of the modeling studies on AChBPs in a search for natural compounds with cholinergic activity and demonstrate the presence of the latter in the analyzed marine biological sources. PMID:24686559

  20. [Glycemia and free sugar levels of the goby Perccottus glehni depending on period before the beginning and after the end of hibernation].

    PubMed

    Karanova, M V

    2009-01-01

    Goby Perccottus glehni is one of the most winterhardy species of fresh-water eurythermal fish. Study of grounds of biochemical adaptation of these animals to hibernation under conditions of ice, which are currently absent, are of undoubted for understanding of the nature of hypometabolic states. This work deals with a study of changes in the content of glucose and other free sugars in goby blood and muscle tissue under different physiological states: active, prehibernation, and arousal after experimental cooling to negative near-zero temperature. (1) A relatively high glycemia level with fluctuation amplitude from 9.8 +/- 2.1 to 24.4 +/- 2.4 mmol/ml is revealed. The minimal value of these fluctuations is recorded at the period almost coinciding with beginning of hibernation, while the maximal value--at the period of artificial termination of the three-month hibernation in ice at -1.5 degrees C. The high blood glycemia level correlating with that in the muscle tissue might probably be due to the protector role of this sugar in adaptive mechanisms of the studied fish not much to winter hypothermia, but rather to the winter hibernation on ice. (2) The level of disaccharide maltose in muscle tissue that is maximal in April is predominantly in reciprocal dependence on the fructose content that is maximal in July. (3) Dynamics of changes in the mono- and disaccharide content depending on the stage of preparation of hibernation basically coincided with the previously revealed dynamics for the fresh-water mollusc Lymnaea stagnalis, which indicated homology of mechanisms of the low-temperature adaptation for animals of different phylogenetic levels. PMID:19569557

  1. Occurrence of a Snail Borne Disease, Cercarial Dermatitis (Swimmer Itch) in Doon Valley (Uttarakhand), India

    PubMed Central

    JAUHARI, Rakesh Kumar; NONGTHOMBAM, Pemola Devi

    2014-01-01

    Abstract Background ‘Cercarial dermatitis’ also known as swimmers itch (Skin allergies) is caused by a trematode parasite, Schistosoma which has two hosts - an invertebrate (snail) and a vertebrate (livestock, human being). Although the availability of both vector snails and pathogens at the selected site the Doon Valley in northern India has already been confirmed but there was a hazy picture of the disease, whether it is due to entrance of cercariae or due to wild variety of grass (Parthenium hysterophorus). The present study is an attempt to provide a way forward towards the vector snails and snail borne diseases in the study area. Methods Snail sampling and identification was done by applying standard methods / using Keys & Catalogues. Associated parasites and cercariometry in snails has been worked out by cercarial shedding. Human involvement at zo-onotic level has been performed in collaboration with Health centers and socio- economic aspect of inhabitants of study area. Results The snail diversity encountered 19 species including the vector species such as Indoplanorbis exustus, Gyraulus convexiusculus, Melanoides tuberculata and Lymnaea acuminata. The cercarial diversity comprised Furcocercous, Monostome, Amphistome and liver fluke / Xiphidiocercaria. During the study (2009–2010), 0.173% was found with cercarial dermatitis among human population in the selected area. The symptoms of disease recorded were red spots and swellings on effected parts of skin. Frequent visits of livestock to the water body and presence of vector snails provides a clue in completing the life cycle of the parasite of the family Schistosomatidae. Conclusion Cercarial dermatitis has been considered a potential risk at those places where warm blooded and snail’s hosts share a link with aquatic bodies with particular emphasis to temperature and time of year. PMID:26060739

  2. Oxidative-stress induced increase in circulating fatty acids does not contribute to phospholipase A2-dependent appetitive long-term memory failure in the pond snail Lymnaeastagnalis

    PubMed Central

    2014-01-01

    Background Reactive oxygen species (ROS) are essential for normal physiological functioning of the brain. However, uncompensated increase in ROS levels may results in oxidative stress. Phospholipase A2 (PLA2) is one of the key players activated by elevated ROS levels resulting in the hydrolysis of various products from the plasmamembrane such as peroxidized fatty acids. Free fatty acids (FFAs) and fatty acid metabolites are often implicated to the genesis of cognitive impairment. Previously we have shown that age-, and experimentally induced oxidative stress causes PLA2-dependent long-term memory (LTM) failure in an aversive operant conditioning model in Lymnaea stagnalis. In the present study, we investigate the effects of experimentally induced oxidative stress and the role of elevated levels of circulating FFAs on LTM function using a non-aversive appetitive classical conditioning paradigm. Results We show that intracoelomic injection of exogenous PLA2 or pro-oxidant induced PLA2 activation negatively affects LTM performance in our learning paradigm. In addition, we show that experimental induction of oxidative stress causes significant temporal changes in circulating FFA levels. Importantly, the time of training coincides with the peak of this change in lipid metabolism. However, intracoelomic injection with exogenous arachidonic acid, one of the main FFAs released by PLA2, does not affect LTM function. Moreover, sequestrating circulating FFAs with the aid of bovine serum albumin does not rescue pro-oxidant induced appetitive LTM failure. Conclusions Our data substantiates previous evidence linking lipid peroxidation and PLA2 activation to age- and oxidative stress-related cognitive impairment, neuronal dysfunction and disease. In addition however, our data indicate that lipid peroxidation induced increased levels of circulating (per)oxidized FFAs are not a factor in oxidative stress induced LTM impairment. PMID:24886155

  3. Development of a solid-phase receptor-based assay for the detection of cyclic imines using a microsphere-flow cytometry system.

    PubMed

    Rodríguez, Laura P; Vilariño, Natalia; Molgó, Jordi; Aráoz, Rómulo; Louzao, M Carmen; Taylor, Palmer; Talley, Todd; Botana, Luis M

    2013-02-19

    Biologically active macrocycles containing a cyclic imine were isolated for the first time from aquaculture sites in Nova Scotia, Canada, during the 1990s. These compounds display a "fast-acting" toxicity in the traditional mouse bioassay for lipophilic marine toxins. Our work aimed at developing a receptor-based detection method for spirolides using a microsphere/flow cytometry Luminex system. For the assay, two alternatives were considered as binding proteins, the Torpedo marmorata nicotinic acetylcholine receptor (nAChR) and the Lymnaea stagnalis acetylcholine binding protein (Ls-AChBP). A receptor-based inhibition assay was developed using the immobilization of nAChR or Ls-AChBP on the surface of carboxylated microspheres and the competition of cyclic imines with biotin-α-bungarotoxin (α-BTX) for binding to these proteins. The amount of biotin-α-BTX bound to the surface of the microspheres was quantified using phycoerythrin (PE)-labeled streptavidin, and the fluorescence was analyzed in a Luminex 200 system. AChBP and nAChR bound to 13-desmethyl spirolide C efficiently; however, the cross-reactivity profile of the nAChR for spirolides and gymnodimine more closely matched the relative toxic potencies reported for these toxins. The nAChR was selected for further assay development. A simple sample preparation protocol consisting of an extraction with acetone yielded a final extract with no matrix interference on the nAChR/microsphere-based assay for mussels, scallops, and clams. This cyclic imine detection method allowed the detection of 13-desmethyl spirolide C in the range of 10-6000 μg/kg of shellfish meat, displaying a higher sensitivity and wider dynamic range than other receptor-based assays previously published. This microsphere-based assay provides a rapid, sensitive, and easily performed screening method that could be multiplexed for the simultaneous detection of several marine toxins. PMID:23343192

  4. Development of a Solid-Phase Receptor-Based Assay for the Detection of Cyclic Imines Using a Microsphere-Flow Cytometry System

    PubMed Central

    Rodríguez, Laura P.; Vilariño, Natalia; Molgó, Jordi; Aráoz, Rómulo; Louzao, M. Carmen; Taylor, Palmer; Talley, Todd; Botana, Luis M.

    2013-01-01

    Biologically active macrocycles containing a cyclic imine were isolated for the first time from aquaculture sites in Nova Scotia, Canada, during the 1990s. These compounds display a “fast-acting” toxicity in the traditional mouse bioassay for lipophilic marine toxins. Our work aimed at developing receptor-based detection method for spirolides using a microsphere/flow cytometry Luminex system. For the assay two alternatives were considered as binding proteins, the Torpedo marmorata nicotinic acetylcholine receptor (nAChR) and the Lymnaea stagnalis acetylcholine binding protein (Ls-AChBP). A receptor-based inhibition assay was developed using the immobilization of nAChR or Ls-AChBP on the surface of carboxylated microspheres and the competition of cyclic imines with biotin-α-bungarotoxin (α-BTX) for binding to these proteins. The amount of biotin-α-BTX bound to the surface of the microspheres was quantified using phycoerythrin (PE)-labeled streptavidin and the fluorescence was analyzed in a Luminex 200 system. AChBP and nAChR bound to 13-desmethyl spirolide C efficiently; however the cross-reactivity profile of the nAChR for spirolides and gymnodimine more closely matched the relative toxic potencies reported for these toxins. The nAChR was selected for further assay development. A simple sample preparation protocol consisting of an extraction with acetone yielded a final extract with no matrix interference on the nAChR/microsphere-based assay for mussels, scallops and clams. This cyclic imine detection method allowed the detection of 13-desmethyl spirolide C in the range of 10–6000 μg/kg of shellfish meat, displaying a higher sensitivity and wider dynamic range than other receptor-based assays previously published. This microsphere-based assay provides a rapid, sensitive and easily performed screening method that could be multiplexed for the simultaneous detection of several marine toxins. PMID:23343192

  5. Deep mRNA Sequencing of the Tritonia diomedea Brain Transcriptome Provides Access to Gene Homologues for Neuronal Excitability, Synaptic Transmission and Peptidergic Signalling

    PubMed Central

    Senatore, Adriano; Edirisinghe, Neranjan; Katz, Paul S.

    2015-01-01

    Background The sea slug Tritonia diomedea (Mollusca, Gastropoda, Nudibranchia), has a simple and highly accessible nervous system, making it useful for studying neuronal and synaptic mechanisms underlying behavior. Although many important contributions have been made using Tritonia, until now, a lack of genetic information has impeded exploration at the molecular level. Results We performed Illumina sequencing of central nervous system mRNAs from Tritonia, generating 133.1 million 100 base pair, paired-end reads. De novo reconstruction of the RNA-Seq data yielded a total of 185,546 contigs, which partitioned into 123,154 non-redundant gene clusters (unigenes). BLAST comparison with RefSeq and Swiss-Prot protein databases, as well as mRNA data from other invertebrates (gastropod molluscs: Aplysia californica, Lymnaea stagnalis and Biomphalaria glabrata; cnidarian: Nematostella vectensis) revealed that up to 76,292 unigenes in the Tritonia transcriptome have putative homologues in other databases, 18,246 of which are below a more stringent E-value cut-off of 1x10-6. In silico prediction of secreted proteins from the Tritonia transcriptome shotgun assembly (TSA) produced a database of 579 unique sequences of secreted proteins, which also exhibited markedly higher expression levels compared to other genes in the TSA. Conclusions Our efforts greatly expand the availability of gene sequences available for Tritonia diomedea. We were able to extract full length protein sequences for most queried genes, including those involved in electrical excitability, synaptic vesicle release and neurotransmission, thus confirming that the transcriptome will serve as a useful tool for probing the molecular correlates of behavior in this species. We also generated a neurosecretome database that will serve as a useful tool for probing peptidergic signalling systems in the Tritonia brain. PMID:25719197

  6. Natural Compounds Interacting with Nicotinic Acetylcholine Receptors: From Low-Molecular Weight Ones to Peptides and Proteins

    PubMed Central

    Kudryavtsev, Denis; Shelukhina, Irina; Vulfius, Catherine; Makarieva, Tatyana; Stonik, Valentin; Zhmak, Maxim; Ivanov, Igor; Kasheverov, Igor; Utkin, Yuri; Tsetlin, Victor

    2015-01-01

    Nicotinic acetylcholine receptors (nAChRs) fulfill a variety of functions making identification and analysis of nAChR subtypes a challenging task. Traditional instruments for nAChR research are d-tubocurarine, snake venom protein α-bungarotoxin (α-Bgt), and α-conotoxins, neurotoxic peptides from Conus snails. Various new compounds of different structural classes also interacting with nAChRs have been recently identified. Among the low-molecular weight compounds are alkaloids pibocin, varacin and makaluvamines C and G. 6-Bromohypaphorine from the mollusk Hermissenda crassicornis does not bind to Torpedo nAChR but behaves as an agonist on human α7 nAChR. To get more selective α-conotoxins, computer modeling of their complexes with acetylcholine-binding proteins and distinct nAChRs was used. Several novel three-finger neurotoxins targeting nAChRs were described and α-Bgt inhibition of GABA-A receptors was discovered. Information on the mechanisms of nAChR interactions with the three-finger proteins of the Ly6 family was found. Snake venom phospholipases A2 were recently found to inhibit different nAChR subtypes. Blocking of nAChRs in Lymnaea stagnalis neurons was shown for venom C-type lectin-like proteins, appearing to be the largest molecules capable to interact with the receptor. A huge nAChR molecule sensible to conformational rearrangements accommodates diverse binding sites recognizable by structurally very different compounds. PMID:26008231

  7. Increase in cyclic AMP concentration in a cerebral giant interneuron mimics part of a memory trace for conditioned taste aversion of the pond snail

    PubMed Central

    Otsuka, Emi; Matsunaga, Miho; Okada, Ryuichi; Yamagishi, Miki; Okuta, Akiko; Lukowiak, Ken; Ito, Etsuro

    2013-01-01

    Conditioned taste aversion (CTA) can be classically conditioned in the pond snail Lymnaea stagnalis and subsequently be consolidated into long-term memory (LTM). The neural trace that subserves CTA-LTM can be summarized as follows: A polysynaptic inhibitory postsynaptic potential recorded in the neuron 1 medial (N1M) cell in the conditioned snails as a result of activation of the cerebral giant cell (CGC) is larger and lasts longer than that in control snails. The N1M cell is ultimately activated by the CGC via the neuron 3 tonic (N3t) cell. That is, the inhibitory monosynaptic inputs from the N3t cell to the N1M cell are facilitated. The N1M and N3t cells are the members of feeding central pattern generator, whereas the CGC is a multimodal interneuron thought to play a key role in feeding behavior. Here we examined the involvement of a second messenger, cAMP, in the establishment of the memory trace. We injected cAMP into the CGC and monitored the potentials of the B3 motor neuron activated by the CGC. B3 activity is used as an index for the synaptic inputs from the N3t cell to the N1M cell. We found that the B3 potentials were transiently enlarged. Thus, when the cAMP concentration is increased in the CGC by taste aversion training, cAMP-induced changes may play a key role in the establishment of a memory trace in the N3t cell. PMID:27493554

  8. Biodiversity of trematodes in their intermediate mollusc and fish hosts in the freshwater ecosystems of Europe.

    PubMed

    Faltýnková, Anna; Sures, Bernd; Kostadinova, Aneta

    2016-03-01

    We analysed two novel databases containing 2,380 and 8,202 host-parasite-locality records for trematode parasites of molluscs and fishes, respectively, to assess the biodiversity of trematodes in their intermediate mollusc and fish hosts in the freshwater environment in Europe. The "mollusc" dataset covers large numbers of pulmonate (29 spp.), "prosobranch" (15 spp.) and bivalve (11 spp.) molluscs acting as first intermediate hosts for 171 trematode species of 89 genera and 35 families. Of these, 23 and 40 species utilise freshwater fishes as definitive and second intermediate hosts, respectively. The most frequently recorded families are the Echinostomatidae Looss, 1899, Diplostomidae Poirier, 1886 and Schistosomatidae Stilles & Hassal, 1898, and the most frequently recorded species are Diplostomum spathaceum (Rudolphi, 1819), D. pseudospathaceum Niewiadomska, 1984 and Echinoparyphium recurvatum (von Linstow, 1873). Four snail species harbour extremely rich trematode faunas: Lymnaea stagnalis (L.) (41 spp.); Planorbis planorbis (L.) (39 spp.); Radix peregra (O.F. Müller) (33 spp.); and R. ovata (Draparnaud) (31 spp.). The "fish" dataset covers 99 fish species of 63 genera and 19 families acting as second intermediate hosts for 66 species of 33 genera and nine families. The most frequently recorded families are the Diplostomidae Poirier, 1886, Strigeidae Railliet, 1919 and Bucephalidae Poche, 1907, and the most frequently recorded species are Diplostomum spathaceum (Rudolphi, 1819), Tylodelphys clavata (von Nordmann, 1832) and Posthodiplostomum cuticola (von Nordmann, 1832). Four cyprinid fishes exhibit the highest species richness of larval trematodes: Rutilus rutilus (L.) (41 spp.); Abramis brama (L.) (34 spp.); Blicca bjoerkna (L.) (33 spp.); and Scardinius erythrophthalmus (L.) (33 spp.). Larval stages of 50 species reported in fish are also reported in freshwater molluscs, thus indicating a relatively good knowledge of the life-cycles of fish trematodes in

  9. Quercetin Targets Cysteine String Protein (CSPα) and Impairs Synaptic Transmission

    PubMed Central

    Xu, Fenglian; Proft, Juliane; Gibbs, Sarah; Winkfein, Bob; Johnson, Jadah N.; Syed, Naweed; Braun, Janice E. A.

    2010-01-01

    Background Cysteine string protein (CSPα) is a synaptic vesicle protein that displays unique anti-neurodegenerative properties. CSPα is a member of the conserved J protein family, also called the Hsp40 (heat shock protein of 40 kDa) protein family, whose importance in protein folding has been recognized for many years. Deletion of the CSPα in mice results in knockout mice that are normal for the first 2–3 weeks of life followed by an unexplained presynaptic neurodegeneration and premature death. How CSPα prevents neurodegeneration is currently not known. As a neuroprotective synaptic vesicle protein, CSPα represents a promising therapeutic target for the prevention of neurodegenerative disorders. Methodology/Principal Findings Here, we demonstrate that the flavonoid quercetin promotes formation of stable CSPα-CSPα dimers and that quercetin-induced dimerization is dependent on the unique cysteine string region. Furthermore, in primary cultures of Lymnaea neurons, quercetin induction of CSPα dimers correlates with an inhibition of synapse formation and synaptic transmission suggesting that quercetin interfers with CSPα function. Quercetin's action on CSPα is concentration dependent and does not promote dimerization of other synaptic proteins or other J protein family members and reduces the assembly of CSPα:Hsc70 units (70kDa heat shock cognate protein). Conclusions/Significance Quercetin is a plant derived flavonoid and popular nutritional supplement proposed to prevent memory loss and altitude sickness among other ailments, although its precise mechanism(s) of action has been unclear. In view of the therapeutic promise of upregulation of CSPα and the undesired consequences of CSPα dysfunction, our data establish an essential proof of principle that pharmaceutical agents can selectively target the neuroprotective J protein CSPα. PMID:20548785

  10. 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.

  11. Effect of cysteine and humic acids on bioavailability of Ag from Ag nanoparticles to a freshwater snail

    USGS Publications Warehouse

    Luoma, Samuel N.; Tasha Stoiber; Croteau, Marie-Noele; Isabelle Romer; Ruth Merrifeild; Jamie Lead

    2016-01-01

    Metal-based engineered nanoparticles (NPs) will undergo transformations that will affect their bioavailability, toxicity and ecological risk when released to the environment, including interactions with dissolved organic material. The purpose of this paper is to determine how interactions with two different types of organic material affect the bioavailability of silver nanoparticles (AgNPs). Silver uptake rates by the pond snail Lymnaea stagnalis were determined after exposure to 25 nmol l-1 of Ag as PVP AgNPs, PEG AgNPs or AgNO3, in the presence of either Suwannee River humic acid or cysteine, a high-affinity thiol-rich organic ligand. Total uptake rate of Ag from the two NPs was either increased or not strongly affected in the presence of 1 – 10 mg 1-1 humic acid. Humic substances contain relatively few strong ligands for Ag explaining their limited effects on Ag uptake rate. In contrast, Ag uptake rate was substantially reduced by cysteine. Three components of uptake from the AgNPs were quantified in the presence of cysteine using a biodynamic modeling approach: uptake of dissolved Ag released by the AgNPs, uptake of a polymer or large (>3kD) Ag-cysteine complex and uptake of the nanoparticle itself. Addition of 1:1 Ag:cysteine reduced concentrations of dissolved Ag, which contributed to, but did not fully explain the reductions in uptake. A bioavailable Ag-cysteine complex (> 3kD) appeared to be the dominant avenue of uptake from both PVP AgNPs and PEG AgNPs in the presence of cysteine. Quantifying the different avenues of uptake sets the stage for studies to assess toxicity unique to NPs.

  12. 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.

  13. Neuron-independent Ca(2+) signaling in glial cells of snail's brain.

    PubMed

    Kojima, S; Ogawa, H; Kouuchi, T; Nidaira, T; Hosono, T; Ito, E

    2000-01-01

    To directly monitor the glial activity in the CNS of the pond snail, Lymnaea stagnalis, we optically measured the electrical responses in the cerebral ganglion and median lip nerve to electrical stimulation of the distal end of the median lip nerve. Using a voltage-sensitive dye, RH155, we detected a composite depolarizing response in the cerebral ganglion, which consisted of a fast transient depolarizing response corresponding to a compound action potential and a slow depolarizing response. The slow depolarizing response was observed more clearly in an isolated median lip nerve and also detected by extracellular recording. In the median lip nerve preparation, the slow depolarizing response was suppressed by an L-type Ca(2+) channel blocker, nifedipine, and was resistant to tetrodotoxin and Na(+)-free conditions. Together with the fact that a delay from the compound action potential to the slow depolarizing response was not constant, these results suggested that the slow depolarizing response was not a postsynaptic response. Because the signals of the action potentials appeared on the saturated slow depolarizing responses during repetitive stimulation, the slow depolarizing response was suggested to originate from glial cells. The contribution of the L-type Ca(2+) current to the slow depolarizing response was confirmed by optical recording in the presence of Ba(2+) and also supported by intracellular Ca(2+) measurement. Our results suggested that electrical stimulation directly triggers glial Ca(2+) entry through L-type Ca(2+) channels, providing evidence for the generation of glial depolarization independent of neuronal activity in invertebrates. PMID:11036223

  14. 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.

  15. Structural and Functional Studies of the Modulator NS9283 Reveal Agonist-like Mechanism of Action at α4β2 Nicotinic Acetylcholine Receptors*

    PubMed Central

    Olsen, Jeppe A.; Ahring, Philip K.; Kastrup, Jette S.; Gajhede, Michael; Balle, Thomas

    2014-01-01

    Modulation of Cys loop receptor ion channels is a proven drug discovery strategy, but many underlying mechanisms of the mode of action are poorly understood. We report the x-ray structure of the acetylcholine-binding protein from Lymnaea stagnalis with NS9283, a stoichiometry selective positive modulator that targets the α4-α4 interface of α4β2 nicotinic acetylcholine receptors (nAChRs). Together with homology modeling, mutational data, quantum mechanical calculations, and pharmacological studies on α4β2 nAChRs, the structure reveals a modulator binding mode that overlaps the α4-α4 interface agonist (acetylcholine)-binding site. Analysis of contacts to residues known to govern agonist binding and function suggests that modulation occurs by an agonist-like mechanism. Selectivity for α4-α4 over α4-β2 interfaces is determined mainly by steric restrictions from Val-136 on the β2-subunit and favorable interactions between NS9283 and His-142 at the complementary side of α4. In the concentration ranges where modulation is observed, its selectivity prevents NS9283 from directly activating nAChRs because activation requires coordinated action from more than one interface. However, we demonstrate that in a mutant receptor with one natural and two engineered α4-α4 interfaces, NS9283 is an agonist. Modulation via extracellular binding sites is well known for benzodiazepines acting at γ-aminobutyric acid type A receptors. Like NS9283, benzodiazepines increase the apparent agonist potency with a minimal effect on efficacy. The shared modulatory profile along with a binding site located in an extracellular subunit interface suggest that modulation via an agonist-like mechanism may be a common mechanism of action that potentially could apply to Cys loop receptors beyond the α4β2 nAChRs. PMID:24982426

  16. How Stress Alters Memory in ‘Smart’ Snails

    PubMed Central

    Dalesman, Sarah; Lukowiak, Ken

    2012-01-01

    Cognitive ability varies within species, but whether this variation alters the manner in which memory formation is affected by environmental stress is unclear. The great pond snail, Lymnaea stagnalis, is commonly used as model species in studies of learning and memory. The majority of those studies used a single laboratory strain (i.e. the Dutch strain) originating from a wild population in the Netherlands. However, our recent work has identified natural populations that demonstrate significantly enhanced long-term memory (LTM) formation relative to the Dutch strain following operant conditioning of aerial respiratory behaviour. Here we assess how two populations with enhanced memory formation (i.e. ‘smart’ snails), one from Canada (Trans Canada 1: TC1) and one from the U.K. (Chilton Moor: CM) respond to ecologically relevant stressors. In control conditions the Dutch strain forms memory lasting 1–3 h following a single 0.5 h training session in our standard calcium pond water (80 mg/l [Ca2+]), whereas the TC1 and CM populations formed LTM lasting 5+ days following this training regime. Exposure to low environmental calcium pond water (20 mg/l [Ca2+]), which blocks LTM in the Dutch strain, reduced LTM retention to 24 h in the TC1 and CM populations. Crowding (20 snails in 100 ml) immediately prior to training blocks LTM in the Dutch strain, and also did so in TC1 and CM populations. Therefore, snails with enhanced cognitive ability respond to these ecologically relevant stressors in a similar manner to the Dutch strain, but are more robust at forming LTM in a low calcium environment. Despite the two populations (CM and TC1) originating from different continents, LTM formation was indistinguishable in both control and stressed conditions. This indicates that the underlying mechanisms controlling cognitive differences among populations may be highly conserved in L. stagnalis. PMID:22384220

  17. A taxonomic revision of two local endemic Radix spp. (Gastropoda: Lymnaeidae) from Khodutka geothermal area, Kamchatka, Russian Far East.

    PubMed

    Bolotov, Ivan; Bespalaya, Yulia; Aksenova, Olga; Aksenov, Andrey; Bolotov, Nikita; Gofarov, Mikhail; Kondakov, Alexander; Paltser, Inga; Vikhrev, Ilya

    2014-01-01

    Khodutka geothermal area is located near Khodutka and Priemysh volcanoes and is one of the largest geothermal areas of the Kamchatka Peninsula. Vakin (2003) described geological, geochemical and geothermic conditions of this geothermal area in detail. The main thermal water sources have temperatures up to 87°C and a discharge of approximately 150 l×sec.-1 are flows out into the warm lake with dimensions of ca. 250 m length and 80 m width. This warm river is ca. 20 m in width beginning from the lake and flows to the Bolshaya Khodutka River basin. Two local endemic Radix species were described from this geothermal area, especially Lymnaea (Radix) hadutkae Kruglov & Starobogatov, 1989 and L. (R.) thermokamtschatica Kruglov & Starobogatov, 1989 (Kruglov & Starobogatov 1989, 1993; Kruglov 2005). These species were separated using proportions of shell and reproductive system (Kruglov & Starobogatov 1989, 1993; Starobogatov et al. 2004). According to the diagnosis, L. (R.) hadutkae differs in the ear-shape shell, a form of the provaginal duct with cylindrical distal part and conical proximal part, and larger value of the index of the copulatory apparatus (ICA: proportion of the preputium to phallotheca is 1.27) from other species within the section Thermoradix Kruglov & Starobogatov, 1989. The last whorl is large, 0.86-0.89 of the shell height; an excess of the last whorl over upper margin of the aperture is 0.15-0.16 of the aperture height. L. (R.) thermokamtschatica has the cylindrical provaginal duct, relatively short bursa duct (1.5X longer than the bursa copulatrix diameter) and very long phallotheca (ICA is 0.77). The last whorl is large, 0.85-0.87 of the shell height; an excess of the last whorl over upper margin of the aperture is 0.2-0.25 of the aperture height. In accordance with an identification key (Starobogatov et al. 2004), the main diagnostic feature is an excess of the last whorl over the shell aperture, which has ≤0.78 and ≥0.80 of the

  18. The effect of pH on chronic aquatic nickel toxicity is dependent on the pH itself: Extending the chronic nickel bioavailability models.

    PubMed

    Nys, Charlotte; Janssen, Colin R; Van Sprang, Patrick; De Schamphelaere, Karel A C

    2016-05-01

    The environmental quality standard for Ni in the European Commission's Water Framework Directive is bioavailability based. Although some of the available chronic Ni bioavailability models are validated only for pH ≤ 8.2, a considerable fraction of European surface waters has a pH > 8.2. Therefore, the authors investigated the effect of a change in pH from 8.2 to 8.7 on chronic Ni toxicity in 3 invertebrate (Daphnia magna, Lymnaea stagnalis, and Brachionus calyciflorus) and 2 plant species (Pseudokirchneriella subcapitata and Lemna minor). Nickel toxicity was almost always significantly higher at pH 8.7 than at pH 8.2. To test whether the existing chronic Ni bioavailability models developed for pH ≤ 8.2 can be used at higher pH levels, Ni toxicity at pH 8.7 was predicted based on Ni toxicity observed at pH 8.2. This resulted in a consistent underestimation of toxicity. The results suggest that the effect of pH on Ni(2+) toxicity is dependent on the pH itself: the slope of the pH effect is steeper above than below pH 8.2 for species for which a species-specific bioavailability model exists. Therefore, the existing chronic Ni bioavailability models were modified to allow predictions of chronic Ni toxicity to invertebrates and plants in the pH range of 8.2 to 8.7 by applying a pH slope (SpH ) dependent on the pH of the target water. These modified Ni bioavailability models resulted in more accurate predictions of Ni toxicity to all 5 species (within 2-fold error), without the bias observed using the bioavailability models developed for pH ≤ 8.2. The results of the present study can decrease the uncertainty in implementing the bioavailability-based environmental quality standard under the Water Framework Directive for high-pH regions in Europe. PMID:26335781

  19. Laboratory assessment of the molluscicidal and cercariacidal activities of Balanites aegyptiaca

    PubMed Central

    Molla, Eshetu; Giday, Mirutse; Erko, Berhanu

    2013-01-01

    Objective To assess the molluscicidal and cercariacidal activities of aqueous extracts of Balanites aegyptiaca (B. aegyptiaca) against Ethiopian Biomphalaria pfeifferi (B. pfeifferi), Lymnaea natalensis (L. natalensis) and Schistosoma mansoni (S. mansoni) cercariae. Methods Extracts of seeds, endocarp, mesocarp, and fruit of B. aegyptiaca were tested for their activities against adult B. pfeifferi and L. natalensis. The cercariacidal activity of the seeds of the plant was also evaluated against S. mansoni. Bioassays were carried out following the methods recommended by WHO. Snail mortalities were compared between each plant part and snail species, and LC50 and LC90 values for the plant parts tested were computed. The cercariacidal activity of the plant was assessed by exposing the mice to the cercariae pre-exposed to aqueous extract of B. aegyptiaca seeds. Results For the molluscicidal activities of seeds, endocarp, mesocarp and whole fruit, the LC50 values against B. pfeifferi were 56.32, 77.53, 65.51 and 66.63 mg/L, respectively, while the respective LC90 values were 77.70, 120.04, 89.50 and 97.55 mg/L. Similarly, the LC50 values for the seeds, endocarp, mesocarp and whole fruit against L. natalensis were 80.33, 92.61, 83.52 and 87.84 mg/L, respectively, while the respective LC90 values were 102.30, 138.21, 115.42 and 127.69 mg/L. B. pfeifferi were found to be more susceptible to B. aegyptiaca than L. natalensis. S. mansoni cercariae exposed to 15 mg/L of extract of seeds were incapable of infecting mice. The mean egg load of tissue was reduced in mice infected with the cercariae exposed to 5 and 10 mg/L of the extract. Conclusions The aqueous extracts of different parts of B. aegyptiaca exhibited reasonable molluscicidal activity against B. pfeifferi and L. natalensis, as well as cercariacidal activity against S. mansoni cercariae. However, comprehensive laboratory evaluation is recommended prior to field tests of the plant parts since their impact on other

  20. Radiation-induced cytogenetic and hematologic effects on aquatic biota within the Chernobyl exclusion zone.

    PubMed

    Gudkov, D I; Shevtsova, N L; Pomortseva, N A; Dzyubenko, E V; Kaglyan, A E; Nazarov, A B

    2016-01-01

    During 1998-2014 the rate of chromosomal aberrations in embryo tissues of the pond snail (Lymnaea stagnalis) and root meristems of higher aquatic plants, and also hematologic indexes of mantle liquid of the adult snails and peripheral blood of fishes in water bodies within the Chernobyl exclusion zone (EZ) was studied. The absorbed dose rate for hydrobionts from water bodies of the EZ registered in a range from 0.25 to 420 μGy h(-1) and in the reference ones - up to 0.09 μGy h(-1). The level of chromosomal aberrations in the molluscs from the most contaminated water bodies of the EZ was registered within range of 18-27% and for the molluscs from the reference lakes this index was on the average 1.5% with the maximal values 2.3%. The rate of chromosomal aberrations in root meristematic cells of higher aquatic plants from the contaminated lakes of the EZ was in range of 7-17% and in the plants from reference water bodies was not exceed 2.1%. The positive correlation between chromosomal aberration rate and absorbed dose rate in the pond snail's embryos and root meristems of higher aquatic plants in water bodies of the EZ was registered. Analysis of hemolymph structure of snails from the most contaminated water bodies showed a high rate of dead and phagocytic cells as well as decrease of the young amoebocytes quantity. Hematologic research of fish allows to determine on the one hand an insignificant changes of leukogram structure, and from the other hand a high level of red cells with different abnormalities in the peripheral blood of fishes from the water bodies with high levels of radioactive contamination. It is suppose that qualitative indexes of red cells in peripheral blood of fish are more sensitive to long-term radiation impact in comparison with elements of white blood, which can be used for conducting of the hematologic monitoring of radioactive contaminated water bodies. PMID:26455549

  1. Transmission rates of the bacterial endosymbiont, Neorickettsia risticii, during the asexual reproduction phase of its digenean host, Plagiorchis elegans, within naturally infected lymnaeid snails

    PubMed Central

    2013-01-01

    Background Neorickettsia are obligate intracellular bacterial endosymbionts of digenean parasites present in all lifestages of digeneans. Quantitative information on the transmission of neorickettsial endosymbionts throughout the complex life cycles of digeneans is lacking. This study quantified the transmission of Neorickettsia during the asexual reproductive phase of a digenean parasite, Plagiorchis elegans, developing within naturally parasitized lymnaeid pond snails. Methods Lymnaea stagnalis snails were collected from 3 ponds in Nelson County, North Dakota and screened for the presence of digenean cercariae. Cercariae were identified to species by PCR and sequencing of the 28S rRNA gene. Neorickettsia infections were initially detected using nested PCR and sequencing of a partial 16S rRNA gene of pooled cercariae shed from each parasitized snail. Fifty to 100 single cercariae or sporocysts were isolated from each of six parasitized snails and tested for the presence of Neorickettsia using nested PCR to estimate the efficiency at which Neorickettsia were transmitted to cercariae during asexual development of the digenean. Results A total of 616 L. stagnalis were collected and 240 (39%) shed digenean cercariae. Of these, 18 (8%) were Neorickettsia-positive. Six Neorickettsia infections were selected to determine the transmission efficiency of Neorickettsia from mother to daughter sporocyst and from daughter sporocyst to cercaria. The prevalence of neorickettsiae in cercariae varied from 11 to 91%. The prevalence of neorickettsiae in sporocysts from one snail was 100%. Conclusion Prevalence of Neorickettsia infection in cercariae of Plagiorchis elegans was variable and never reached 100%. Reasons for this are speculative, however, the low prevalence of Neorickettsia observed in some of our samples (11 to 52%) differs from the high prevalence of other, related bacterial endosymbionts, e.g. Wolbachia in Wolbachia-dependent filariid nematodes, where the prevalence

  2. Fasciolosis in cattle in Louisiana. II. Development of a system to use soil maps in a geographic information system to estimate disease risk on Louisiana coastal marsh rangeland.

    PubMed

    Zukowski, S H; Wilkerson, G W; Malone, J B

    1993-03-01

    A geographic information system (GIS) model of habitat for Lymnaea bulimoides, the snail intermediate host of Fasciola hepatica and the rumen fluke, Calicophoron microbothrioides, on the Chenier Plain of southwest Louisiana was revised to incorporate broad (greater than 100 m) chenier (relict beaches) along with adjacent marsh and transitional soils associated with spatial distribution of L. bulimoides habitat. The proportion of farmland comprised of soils of the GIS model coincided with actual habitat from a previous survey with a sensitivity of 91.3% and a specificity of 80.1%, and regressed significantly against the proportion of farmland comprised of L. bulimoides habitat (n = 12, P = 0.01, r2 = 0.50, slope = 0.015). A soil model index was calculated to incorporate (1) the proportion of farmland comprised of soils of the GIS model and (2) stocking rate. Fluke egg shedding indices (mean egg count multiplied by prevalence) were calculated for each fluke species on nine farms at four sampling times over a 2-year period. The maximum egg shedding indices for each farm, taken to indicate potential fluke transmission intensity, were correlated for the two fluke species on herds not recently treated for fasciolosis (n = 9, P = 0.004, r2 = 0.72, slope = 0.2), although at no one sampling period were shedding indices of the two fluke species significantly correlated. Egg shedding of C. microbothrioides by cattle correlated with the proportion of farmland comprised of soils included in the GIS model (n = 9, Spearman's rank coefficient was 0.7, P = 0.05). We conclude that (1) the maximum of several observations of the C. microbothrioides egg shedding index may be useful as a surrogate for F. hepatica in estimating risk from snail habitat on a farm when regular flukicide treatment interferes with F. hepatica egg shedding, and (2) the GIS model may estimate site-specific differences in fasciolosis risk to cattle operations in the Chenier Plain based on the association of

  3. Influence of hardness on the bioavailability of silver to a freshwater snail after waterborne exposure to silver nitrate and silver nanoparticles.

    PubMed

    Stoiber, Tasha; Croteau, Marie-Noële; Römer, 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 AgNO(3) 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 AgNO(3). 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 (k(uw), 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. PMID:25676617

  4. [Latin American malacology. Freshwater mollusks from Argentina].

    PubMed

    Rumi, Alejandra; Gregoric, Diego E Gutiérrez; Núñez, Verónica; Darrigran, Gustavo A

    2008-03-01

    . Species of sanitary interest are the propagators of: schistosomiasis -Biomphalaria peregrina, B. straminea y B. tenagophila, Planorbidae-, fasciolasis -Lymnaea viatrix and L. columnella, Lymnaeidae- and dermatitis -Chilina gibbosa and C. fluminea, Chilinidae. Invasive species are: Corbicula fluminea (Corbiculidae) and Limnoperna fortunei (Mytilidae). The construction of new areas for the protection and conservation of the high risk endemic species of freshwater molluscs is a priority. It is necessary to give special attention to the species of the patagonic mountain range and of the mesopotamic area of the Del Plata Basin. PMID:18624229

  5. The effect of organic and inorganic aqueous uranium speciation on U(VI) bioavailability to an aquatic invertebrate

    NASA Astrophysics Data System (ADS)

    Fuller, C.; Croteau, M. N.; Campbell, K. M.; Cain, D.; Aiken, G.

    2015-12-01

    Growing world-wide demand for uranium (U) as an energy source has raised concerns of the human and ecological risks of U extraction and processing in the United States. Because of limited information on the relationship between U speciation and bioavailability, particularly in aquatic animals, we are characterizing U uptake by a model freshwater invertebrate (the snail Lymnaea stagnalis). This species grazes on biofilms and is thus key in the trophic transfer of contaminants through aquatic food webs. We determined the bioavailability of dissolved U(VI) over a range of water hardness, pH (6 to 8), and the presence of dissolved natural organic matter (NOM) as a competing ligand, to test the effect of aqueous speciation on uptake. Bioavailability was assessed using U uptake rate constants (kuw) derived from a kinetic bioaccumulation model. Dissolved U (1 to 1000 nM) was bioavailable over the range of geochemical conditions tested with kuw (L/g/d) decreasing with increasing dissolved Ca and with increasing pH. For example, kuw decreased from 1.6 to 0.3 as dissolved Ca was increased from 0.04 to 1.5 mM, suggesting competition between bioavailable U(VI) species and strong ternary calcium uranyl carbonato complexes. At pH 7.5 in synthetic moderately hard freshwater, kuw decreased from 0.22 in the absence of NOM to 0.07 in the presence of a hydrophobic acid NOM isolate of high aromaticity (SUVA = 5) consistent with strong aqueous complexation of U(VI) by the NOM. The co-variance of U uptake and aqueous U species distribution is being analyzed to determine which U species are bioavailable. U speciation in systems with NOM is calculated using conditional U-NOM binding constants derived by equilibrium dialysis ligand exchange methodology. The bioavailability of dietborne U is being tested since dietary metal uptake prevails for many aquatic species. These experiments include addition of ferrihydrite with U sorbed, both in the presence and absence of NOM, and mixed with diet.

  6. Toxicity of lead (Pb) to freshwater green algae: development and validation of a bioavailability model and inter-species sensitivity comparison.

    PubMed

    De Schamphelaere, K A C; Nys, C; Janssen, C R

    2014-10-01

    model to reduce uncertainty in site-specific risk assessment. A model-based comparison with other species indicated that the sensitivity difference between P. subcapitata and two of the most chronically Pb-sensitive aquatic invertebrates (the crustacean Ceriodaphnia dubia and the snail Lymnaea stagnalis) is strongly pH dependent, with P. subcapitata becoming the most sensitive of the three at pH > 7.4. This indicates that inter-species differences in Pb bioavailability relationships should be accounted for in risk assessment and in the derivation of water quality criteria or environmental quality standards for Pb. The chronic toxicity data with three algae species and the bioavailability model presented here will help to provide a stronger scientific basis for evaluating ecological effects of Pb in the freshwater environment. PMID:25089923

  7. Reworked planktonic Foraminifera from the Late Rupelian of the southern Upper Rhine Graben and their palaeogeographic and biostratigraphic implications

    NASA Astrophysics Data System (ADS)

    Pirkenseer, C.; Spezzaferri, S.; Berger, J.-P.

    2009-04-01

    margin of the Upper Rhine Graben. Reworked Mesozoic and Paleogene calcareous nannoplankton from the Upper Rhine Graben and the Mainz Basin confirms the data derived from planktonic Foraminifera. The existence of reworked planktonic Foraminifera influences the biostratigraphic interpretation of the assemblage ranges attributed to "Série grise" samples. Facultatively reworked planktonic Foraminifera as Subbotina utilisindex and Pseudohastigerina micra ranging from the Lutetian to the Late Rupelian should not be included in the biostratigraphic analyses, as the occurrences of these facultatively reworked species are always linked to those of exclusively Cretaceous and Eocene age. Therefore the age of the "Série grise" deposits at Allschwil-2 is most likely to be placed within the "Chiloguembelina cubensis - Globigerinella obesa / Globorotaloides variabilis"-assemblage range of Mid P20 to Final P21a, lasting considerably longer than the very short Mid P20 range based on the presence of Pseudohastigerina micra as "last occurrence"-marker (PIRKENSEER 2007). This study was funded by the Swiss National Science Foundation projects 109457 and 118025. References: BERGER, J.-P., REICHENBACHER, B., BECKER, D., et al. (2005): Eocene-Pliocene time scale and stratigraphy of the Upper Rhine Graben (URG) and the Swiss Molasse Basin (SMB). - International Journal of Earth Sciences, 94, 4: 711-731. FISCHER, H. (1965): Geologie des Gebietes zwischen Blauen und Pfirter Jura. - Beiträge zur geologischen Karte der Schweiz, NF 122: 106p. PIRKENSEER, C. (2007): Foraminifera, Ostracoda and other microfossils of the Southern Upper Rhine Graben - Palaeoecology, biostratigraphy, palaeogeography and geodynamic implications. - PhD thesis: 340p, Fribourg. ROUSSÉ, S. (2006): Architecture et dynamique des séries marines et continentales de ĺOligocène Moyen et Supérieur du Sud du Fossé Rhénan: Evolution des milieux de dépôt en contexte de rift en marge de ĺavant-pays alpin. - PhD: 471p