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1

The toxicity and physiological effects of copper on the freshwater pulmonate snail, Lymnaea stagnalis  

E-print Network

Keywords: Gastropods Lymnaea stagnalis Copper Water quality criteria Ionoregulation Acid­base balance Several recent studies have demonstrated that the freshwater pulmonate snail Lymnaea stagnalisThe toxicity and physiological effects of copper on the freshwater pulmonate snail, Lymnaea

Grosell, Martin

2

Trematode infection alters the antipredator behavior of a pulmonate snail  

Microsoft Academic Search

Parasites can alter the behavior, life history, and morphology of their host. Many trem- atodes parasitize freshwater pulmonate snails, resulting in a reduction or the elimination of repro- duction in those individuals. However, parasite effects on freshwater snail behavior are unclear. I measured trematode infection rates, size, and covered habitat use of the freshwater pulmonate snail Physa integra in a

RANDALL J. BERNOT

2003-01-01

3

High net calcium uptake explains the hypersensitivity of the freshwater pulmonate snail, Lymnaea stagnalis, to chronic lead exposure  

Microsoft Academic Search

Previous studies have shown that freshwater pulmonate snails of the genus Lymnaea are exceedingly sensitive to chronic Pb exposure. An EC20 of <4?gl?1Pb for juvenile snail growth has recently been determined for Lymnaea stagnalis, which is at or below the current USEPA water quality criterion for Pb. We characterized ionoregulation and acid–base balance in Pb-exposed L. stagnalis (young adults ?1g)

Martin Grosell; Kevin V. Brix

2009-01-01

4

Bleeding of pulmonate snails.  

PubMed

A technique for removing blood (haemolymph) by syringe from African land snails (Achatina spp.) is described. The method avoids the need for shell perforation or incision of soft tissues and appears to have few adverse effects on the snail. PMID:7967469

Cooper, J E

1994-07-01

5

INTRODUCTION Embryos of the freshwater common pond snail Lymnaea stagnalis  

E-print Network

4092 INTRODUCTION Embryos of the freshwater common pond snail Lymnaea stagnalis complete direct retention (Baldwin, 1935). Metamorphosis and shell formation have been observed for Lymnaea palustris (Morrill, 1982), L. stagnalis (Ebanks et al., 2010) and another freshwater pulmonate snail Biomphalaria

Grosell, Martin

6

Predation and the distribution and abundance of a pulmonate pond snail  

Microsoft Academic Search

The abundances of a freshwater pulmonate snail, Lymnaea elodes were studied in a temporary pond and a permanent, more productive pond in northeastern Indiana, USA. When snails from both populations were reared in each of the ponds in containers excluding predators, snails grew to be 1.3 to 2 times as large in the more productive pond, and laid 9 times

Kenneth M. Brown; Dennis R. DeVries

1985-01-01

7

Effects of chronic waterborne nickel exposure on growth, ion homeostasis, acid-base balance, and nickel uptake in the freshwater pulmonate snail, Lymnaea stagnalis.  

PubMed

The freshwater pulmonate snail, Lymnaea stagnalis, is the most sensitive aquatic organism tested to date for Ni. We undertook a series of experiments to investigate the underlying mechanism(s) for this observed hypersensitivity. Consistent with previous experiments, juvenile snail growth in a 21-day exposure was reduced by 48% relative to the control when exposed to 1.3 ?g l(-1) Ni (EC20 less than the lowest concentration tested). Ca(2+) homeostasis was significantly disrupted by Ni exposure as demonstrated by reductions in net Ca(2+) uptake, and reductions in Ca(2+) concentrations in the hemolymph and soft tissues. We also observed reduced soft tissue [Mg(2+)]. Snails underwent a significant alkalosis with hemolymph pH increasing from 8.1 to 8.3 and hemolymph TCO2 increasing from 19 to 22 mM in control versus Ni-exposed snails, respectively. Unlike in previous studies with Co and Pb, snail feeding rates were found to be unaffected by Ni at the end of the exposure. Snails accumulated Ni in the soft tissue in a concentration-dependent manner, and Ni uptake experiments with (63)Ni revealed a biphasic uptake profile - a saturable high affinity component at low exposure concentrations (36-189 nM) and a linear component at the high exposure concentrations (189-1,897 nM). The high affinity transport system had an apparent Km of 89 nM Ni(2+) and Vmax of 2.4 nmol g(-1)h(-1). This equates to a logK of 7.1, significantly higher than logK's (2.6-5.2) for any other aquatic organisms evaluated to date, which will have implications for Biotic Ligand Model development. Finally, pharmacological inhibitors that block Ca(2+) uptake pathways in snails did not inhibit Ni uptake, suggesting that the uptake of Ni does not occur via Ca(2+) uptake pathways. As with Cu and Pb, the exact mechanism for the significant disruption in Ca(2+) homeostasis and reduction in juvenile snail growth remains unknown. PMID:24632313

Niyogi, Som; Brix, Kevin V; Grosell, Martin

2014-05-01

8

Growth inhibition in early life-stage tests predicts full life-cycle toxicity effects of lead in the freshwater pulmonate snail, Lymnaea stagnalis.  

PubMed

The freshwater pulmonate snail, Lymnaea stagnalis, is the most sensitive freshwater organism tested to date for several metals (Co, Cu, Pb, Ni) based on 28 d early life-stage (ELS) tests in which growth was the most sensitive endpoint. The United States Environmental Protection Agency (USEPA) has expressed concern that growth in 28 d ELS tests with mollusks may overpredict toxicity because of the potential for recovery in a full life-cycle (LC) test. Consequently, the USEPA only accepts the survival endpoint for these tests in establishing water quality criteria (WQC). To address this concern, the current study aimed to test the sensitivity of L. stagnalis to Pb in a 56 d full LC test evaluating survival, growth, reproductive and embryonic growth endpoints and compare the estimated effect levels to those established using the 28 d ELS test design. The most sensitive endpoints in this study were 28 d growth and 56 d egg mass production, both with a NOEC of <1.0 ?g L(-1) and a LOEC of 1.0 ?g L(-1), showing that the ELS growth endpoint is predictive of the 56 d reproduction endpoint. Snails exposed to 1.0 and 2.7 ?g L(-1) Pb showed full and partial recovery from growth inhibition between 28 and 56 d. While this recovery supports the USEPA's concern about the 28 d growth endpoint; considering the reproductive lifespan of L. stagnalis and the recovery dose-response, we conclude that the 28 d growth endpoint will be within a factor of 3 of full LC endpoints. This is consistent with the level of precision previously determined for fish ELS tests, which the USEPA accepts for WQC derivation, and suggests that tests using 28 d ELS growth endpoint for L. stagnalis may be acceptable for inclusion in WQC derivation. PMID:23274352

Munley, Kathleen M; Brix, Kevin V; Panlilio, Jennifer; Deforest, David K; Grosell, Martin

2013-03-15

9

Chiral Speciation in Terrestrial Pulmonate Snails  

PubMed Central

On the basis of data in the literature, the percentages of dextral versus sinistral species of snails have been calculated for western Europe, Turkey, North America (north of Mexico), and Japan. When the family of Clausiliidae is represented, about a quarter of all snail species may be sinistral, whereas less than one per cent of the species may be sinistral where that family does not occur. The number of single-gene speciation events on the basis of chirality, resulting in the origin of mirror image species, is not closely linked to the percentage of sinistral versus dextral species in a particular region. Turkey is nevertheless exceptional by both a high percentage of sinistral species and a high number of speciation events resulting in mirror image species. Shell morphology and genetic background may influence the ease of chirality-linked speciation, whereas sinistrality may additionally be selected against by internal selection. For the Clausiliidae, the fossil record and the recent fauna suggest that successful reversals in coiling direction occurred with a frequency of once every three to four million years. PMID:22532825

Gittenberger, Edmund; Hamann, Thomas D.; Asami, Takahiro

2012-01-01

10

Uranium exposure to the tropical duckweed Lemna aequinoctialis and pulmonate snail Amerianna cumingi: fate and toxicity.  

PubMed

The discharge of catchment-management water from the Ranger uranium (U) mine into Magela Creek upstream of the Ramsar-listed Magela Floodplain in Kakadu National Park is an important part of the mine's water-management system. Because U is one of the primary toxicants associated with this water, a receiving-water trigger value (TV), based on chronic toxicity data from five local native species, was derived for U. To strengthen the data set underpinning the derivation of the TV, the chronic toxicity of U to two additional tropical freshwater species, duckweed Lemna aequinoctialis (96-hour growth rate), and pulmonate gastropod, Amerianna cumingi (96-hour reproduction), was determined. The fate of U within the test systems was an important component of the study because analysis of U concentrations during the snail tests indicated that a substantial proportion of U (approximately 25%) was being lost from the test solutions when integrated during the entire test duration. Analysis of the snails and their food for U indicated that only a small proportion that was lost from solution was being taken up by the snails. Therefore, the majority of U that was lost was considered unavailable to the snails, and thus the exposure concentrations used to calculate the toxicity estimates were adjusted downward. Integrating the loss of U from the L. aequinoctialis test solutions over time showed that only a small proportion (6% to 13%) was lost during the test: Of that, almost half (2-5%) was taken up by the plants (constituting exposure). Uranium was only moderately toxic to L. aequinoctialis, with no observed-effect concentrations, lowest observed-effect concentrations, and inhibition concentrations causing 10% and 50% effects (IC10 and IC50) values of 226, 404, 207, and 1435 microg/l, respectively. A. cumingi was found to be more sensitive to U than L. aequinoctialis, with NOEC, LOEC, IC10, and IC50 values of 60, 61, 15, and 278 microg/l, respectively. The data for these two additional species will be used to revise the current TV for U in Magela Creek. PMID:20127482

Hogan, Alicia C; van Dam, Rick A; Houston, Melanie A; Harford, Andrew J; Nou, Suthidha

2010-08-01

11

Thermal Compensation of Respiration in Pulmonate Snails (Pulmonata) of Arion and Deroceras Genera Living in Polar and Temperate Climatic Zone  

Microsoft Academic Search

Comparison of respiration rate in pulmonate snails living in various climatic zones demonstrated higher constant a in representatives of Arion genus (A. subfuscus and A. fasciatus) from Polar Area (Murmansk Region) as compared to inhabitants of temperate latitudes (Moscow Region). The snails of Deroceras genus (D. reticulatum) from these two climatic zones were indistinguishable by relative standard metabolism. Different effects

A. A. Zotin; N. D. Ozernyuk

2002-01-01

12

Survey of Pulmonate Snails of Central Minnesota. I. Lymnaeidae  

Microsoft Academic Search

Aquatic snails were collected at 148 sites from various wetland habitats in central Minnesota between May and September, 1988. Ten lymnaeid species were collected, including Lymnaea palustris, L. stagnalis, L. exilis, L. caperata, L. catascopium, L. megasoma, L. (Fossaria) modicella, L. (F.) parva, L. (E.) bulimoides, and L. (F.) dalli. These species were found at 30-, 18-, 15, 12-, 11-,

Jeffrey R. Laursen; Gary A. Averbeck; Gary A. Conboy; Bert E. Stromberg

1992-01-01

13

The Heritability of Shell Morphometrics in the Freshwater Pulmonate Gastropod Physa  

PubMed Central

The cosmopolitan freshwater pulmonate snail Physa acuta hybridizes readily with Physa carolinae in the laboratory, although their F1 progeny are sterile. The two species differ qualitatively in shell shape, the former bearing a more globose shell and the latter more fusiform. We performed a hybridization experiment, measuring a set of 14 traditional (linear) and landmark-based shell morphological variables on even-aged parents and their offspring from both hybrids and purebred control lines. Parent-offspring regression yielded a strikingly high heritability estimate for score on the first relative warp axis, h2 = 0.819 ± 0.073, a result that would seem to confirm the value of geometric morphometrics as a tool for retrieving evolutionary relationships from gastropod shell form. Score on the second relative warp axis was also significantly heritable (h2 = 0.312 ± 0.123), although more moderate, as were scores on second principal components extracted from traditional measurements (correlation h2 = 0.308 ± 0.069, covariance h2 = 0.314 ± 0.050). Although score on the first relative warp axis was significantly correlated with centroid size (p < 0.001), scores on none of the three second axes were so correlated. This result suggests that second axis score might prove especially useful for estimating genetic divergence among mixed-age populations of gastropods sampled from the field. PMID:25876155

Dillon, Robert T.; Jacquemin, Stephen J.

2015-01-01

14

[Thermal compensation of respiration in pulmonate snails (Pulmonata) of Arion and Deroceras genera living in polar and temperate climatic zone].  

PubMed

Comparison of respiration rate in pulmonate snails living in various climatic zones demonstrated higher constant a in representatives of Arion genus (A. subfucus and A. fasciatus) from Polar Area (Murmansk Region) as compared to inhabitants of temperate latitudes (Moscow Region). The snails of Deroceras genus (D. reticulatum) from these two climatic zones were indistinguishable by relative standard metabolism. Different effects of climatic thermal conditions on respiration rates in representatives of these two snail genera can be due to their specific biology. Representatives of Deroceras genus are short-cycle synanthropic species, while the snails of Arion genus are long-cycle species living mostly in the forest zone. PMID:12400380

Zotin, A A; Ozerniuk, N D

2002-01-01

15

Characterization of 15 microsatellite loci in the pulmonate snail Pseudosuccinea columella (Mollusca, Gastropoda)  

Microsoft Academic Search

We characterized 15 new variable microsatellites in the freshwater snail Pseudosuccinea (Lymnaea) columella, as well as conditions for multiplexing and simultaneously genotyping sets of loci. Two to six alleles were detected per locus over the six populations studied. Gene diversity ranged from 0.000 to 0.498, but essentially no heterozygous individuals were observed. This resulted in extremely high FIS estimates, and

ANTOINE NICOT; MARIE-PIERRE DUBOIS; CHANTAL DEBAIN; PATRICE DAVID; PHILIPPE JARNE

2008-01-01

16

[Molluscacide activity of piquerol A isolated from Piqueria trinervia (Compositae) on 8 species of pulmonate snails].  

PubMed

In laboratory trials an aqueous solution of Piquerol A from Piqueria trinervia, collected in several regions of Mexico, showed a molluscicide action on the adults of eight different pulmonates snails species: Fossaria (Fossaria) humilis, F. (Bakerilymnaea) sp., Pseudosuccinea columella and Stagnicola attenuata from Mexico; F. (B.) cubensis and Physa cubensis from Cuba; P. columella and Biomphalaria glabrata from Brazil; B. glabrata from Puerto Rico; and S. elodes from U.S.A. The solution was tested at 50, 25 and 5 ppm concentration, for two periods of 6 and 24 hours, at room temperature (20-22 degrees C). A 100% mortality was obtained for all species at 50 ppm concentration after 6 hours of exposure; the same percentage at 25 ppm after 24 hours; and 60 to 100% mortality at 5 ppm concentration during 24 hours of exposure. No recovery was observed among any of the treated snails. Piquerol A is a sesquiterpene with low stability in nature and has previously only been tested as an insecticide and as an inhibitor of metabolism in cell cultures: no field trails have been made on its toxicity to other aquatic fauna as yet, but it is believed Piquerol A could be an excellent molluscicide for use in areas where focal transmission of schistosomiasis and fascioliasis are taking place. This is the first time experiments on molluscicides have been carried out in Mexico. PMID:2319950

Cruz-Reyes, A; Chavarin, C; Campos Arias, M P; Taboada, J; Jimenez, M

1989-01-01

17

Isolation, Characterization, and Evolutionary Aspects of a cDNA Clone Encoding Multiple Neuropeptides Involved in the Stereotyped Egg-Laying Behavior of the Freshwater Snail Lymnaea sfagnalis  

Microsoft Academic Search

The cerebral neurosecretory caudodorsal cells (CDCs) of the freshwater pulmonate snail Lymnaea stagnalis control egg laying, an event that involves a pattern of stereotyped be- haviors. The CDCs synthesize and release multiple peptides, among which is the ovulation hormone (CDCH). It is thought that each peptide controls a specific aspect of the processes involved in egg laying. We isolated and

E. Vreugdenhil; J. F. Jackson; T. Bouwmeester; A. B. Smit; J. Van Minnen; H. Van Heerikhuizen

1988-01-01

18

Key to the identification of East and Central African freshwater snails of medical and veterinary importance*  

PubMed Central

This identification key has been prepared to enable field workers in eastern and centra Africa to identify the species and subspecies of snails acting as intermediate hosts of various flukes causing bilharziasis and related diseases in man and his domestic stock. The area covered by the key is eastern Africa from the Sudan and Somalia in the north to Southern Rhodesia in the south. The key includes all species and subspecies of the three medically and veterinarily important genera, Lymnaea, Bulinus and Biomphalaria. All other freshwater pulmonates of the area can be identified as to genus only. Those features of the shells and soft parts of snails which are used in identification are discussed in some detail, and indications are given as to methods of collection, preservation and dissection of snails. PMID:14469160

Mandahl-Barth, G.

1962-01-01

19

Physiological and biochemical responses to cold and drought in the rock-dwelling pulmonate snail, Chondrina avenacea.  

PubMed

The pulmonate snail Chondrina avenacea lives on exposed rock walls where it experiences drastic daily and seasonal fluctuations of abiotic conditions and food availability. We found that tolerance to dry conditions was maintained at a very high level throughout the year and was mainly based on the snails' ability to promptly enter into estivation (quiescence) whenever they experienced drying out of their environment. Snails rapidly suppressed their metabolism and minimized their water loss using discontinuous gas exchange pattern. The metabolic suppression probably included periods of tissue hypoxia and anaerobism as indicated by accumulation of typical end products of anaerobic metabolism: lactate, alanine and succinate. Though the drought-induced metabolic suppression was sufficient to stimulate moderate increase of supercooling capacity, the seasonally highest levels of supercooling capacity and the highest tolerance to subzero temperatures were tightly linked to hibernation (diapause). Hibernating snails did not survive freezing of their body fluids and instead relied on supercooling strategy which allowed them to survive when air temperatures dropped to as low as -21 °C. No accumulation of low-molecular weight compounds (potential cryoprotectants) was detected in hibernating snails except for small amounts of the end products of anaerobic metabolism. PMID:23516021

Koštál, Vladimír; Rozsypal, Jan; Pech, Pavel; Zahradní?ková, Helena; Šimek, Petr

2013-08-01

20

Characterization of 15 microsatellite loci in the pulmonate snail Pseudosuccinea columella (Mollusca, Gastropoda).  

PubMed

We characterized 15 new variable microsatellites in the freshwater snail Pseudosuccinea (Lymnaea) columella, as well as conditions for multiplexing and simultaneously genotyping sets of loci. Two to six alleles were detected per locus over the six populations studied. Gene diversity ranged from 0.000 to 0.498, but essentially no heterozygous individuals were observed. This resulted in extremely high F(IS) estimates, and therefore high selfing rates. The F(ST) estimates ranged from 0.18 to 1 among populations, but was generally high. These markers will constitute efficient tools for investigating the population structure of this invasive species. Cross-species amplification was on the whole unsuccessful. PMID:21586021

Nicot, Antoine; Dubois, Marie-Pierre; Debain, Chantal; David, Patrice; Jarne, Philippe

2008-11-01

21

The influence of diet on the ? 13C of shell carbon in the pulmonate snail Helix aspersa  

NASA Astrophysics Data System (ADS)

The influence of diet and atmospheric CO 2 on the carbon isotope composition of shell aragonite and shell-bound organic carbon in the pulmonate snail Helix aspersa raised in the laboratory was investigated. Three separate groups of snails were raised on romaine lettuce (C3 plant, ? 13C=-25.8‰), corn (C4 plant, ? 13C=-10.5‰), and sour orange ( 12C-enriched C3 plant, ? 13C=-39.1‰). The isotopic composition of body tissues closely tracked the isotopic composition of the snail diet as demonstrated previously. However, the isotopic composition of the acid insoluble organic matrix extracted from the aragonite shells does not track diet in all groups. In snails that were fed corn the isotopic composition of the organic matrix was more negative than the body by as much as 5‰ whereas the matrix was approximately 1‰ heavier than the body tissues in snails fed a diet of C3 plant material. These results indicate that isotopic composition of the organic matrix carbon cannot be used as an isotopic substrate for paleodietary reconstructions without first determining the source of the carbon and any associated fractionations. The isotopic composition of the shell aragonite is offset from the body tissues by 12.3‰ in each of the culture groups. This offset was not influenced by the consumption of carbonate and is not attributable to the diffusion of atmospheric CO 2 into the hemolymph. The carbon isotopic composition of shell aragonite is best explained in terms of equilibrium fractionations associated with exchange between metabolic CO 2 and HCO 3 in the hemolymph and the fractionation associated with carbonate precipitation. These results differ from previous studies, based primarily on samples collected in the field, that have suggested atmospheric carbon dioxide contributes significantly to the shell ? 13C. The culture results indicate that the ? 13C of aragonite is a good recorder of the isotopic composition of the snail body tissue, and therefore a better recorder of diet than is the insoluble shell organic carbon. Because the systematic fractionation of carbon isotopes within the snail is temperature dependent, the ? 13C of the shell could provide an independent technique for estimating paleotemperature changes.

Stott, Lowell D.

2002-02-01

22

Inter- and intraspecific trait compensation of defence mechanisms in freshwater snails.  

PubMed

Trait compensation occurs when mechanically independent adaptations are negatively correlated. Here, we report the first study to demonstrate trait compensation in predator-defence adaptations across several species. Freshwater pulmonate snails exposed experimentally to predation chemical cues from fishes and crushed conspecifics showed clear interspecific differences in their behavioural avoidance responses, which were negatively correlated with shell crush resistance. The type of avoidance response varied between species: thin-shelled species (Lymnaea stagnalis and Physa fontinalis) moved to the water-line or out of the water, while those with thick shells moved under cover or showed a mixed response. There were also intraspecific size-linked differences, with an ontogenetic increase in shell strength accompanied by a decrease in behavioural avoidance. Such trait compensation in response to predation has important implications for interspecific interactions and food-web dynamics. PMID:11454289

Rundle, S D; Brönmark, C

2001-07-22

23

Why get big in the cold? Size-fecundity relationships explain the temperature-size rule in a pulmonate snail (Physa).  

PubMed

Most ectotherms follow a pattern of size plasticity known as the temperature-size rule where individuals reared in cold environments are larger at maturation than those reared in warm environments. This pattern seems maladaptive because growth is slower in the cold so it takes longer to reach a large size. However, it may be adaptive if reaching a large size has a greater benefit in a cold than in a warm environment such as when size-dependent mortality or size-dependent fecundity depends on temperature. I present a theoretical model showing how a correlation between temperature and the size-fecundity relationship affects optimal size at maturation. I parameterize the model using data from a freshwater pulmonate snail from the genus Physa. Nine families were reared from hatching in one of three temperature regimes (daytime temperature of 22, 25 or 28 °C, night-time temperature of 22 °C, under a 12L : 12D light cycle). Eight of the nine families followed the temperature-size rule indicating genetic variation for this plasticity. As predicted, the size-fecundity relationship depended upon temperature; fecundity increases steeply with size in the coldest treatment, less steeply in the intermediate treatment, and shows no relationship with size in the warmest treatment. Thus, following the temperature-size rule is adaptive for this species. Although rarely measured under multiple conditions, size-fecundity relationships seem to be sensitive to a number of environmental conditions in addition to temperature including local productivity, competition and predation. If this form of plasticity is as widespread as it appears to be, this model shows that such plasticity has the potential to greatly modify current life-history theory. PMID:25404100

Arendt, J

2015-01-01

24

Snails as Biomonitors of Oil-Spill and Bioremediation Strategies  

Microsoft Academic Search

Aquatic and pulmonate snails were evaluated for their suitability as biomonitors of habitat recovery following an experimental oil spill in a freshwater marshland. The mystery snail, Viviparus georgianus, and the mimic pondsnail, Pseudosuccinea columella, were used as sediment quality biomonitors for a controlled oil-spill experiment at a wetland site along the St. Lawrence River (Ste. Croix, Quebec) to assess the

L. E. J. Lee; J. Stassen; A. McDonald; C. Culshaw; A. D. Venosa; K. Lee

2002-01-01

25

Bioconcentration ratio of diazinon by freshwater fish and snail  

Microsoft Academic Search

Summary The bioconcentration ratios of diazinon from water by freshwater fishes were generally larger than that of crayfish and snails. Among fishes, the bioconcentration ratio of diazinon by topmouth gudgeon was the highest value, 152 being average. However, elimination of diazinon from fish body was linearly rapid. The influence of test concentration on the bioconcentration ratio was not so much

Jun Kanazawa

1978-01-01

26

Accelerated Mutation Accumulation in Asexual Lineages of a Freshwater Snail  

E-print Network

Sexual reproduction is both extremely costly and widespread relative to asexual reproduction, meaning to contribute to the short-term evolutionary mechanisms that favor sexual reproduction. Key words: sex, asexualAccelerated Mutation Accumulation in Asexual Lineages of a Freshwater Snail Maurine Neiman,*,1 Gery

Neiman, Maurine

27

Control of feeding movements in the freshwater snail Planorbis corneus  

Microsoft Academic Search

(1) The buccal mass of the freshwater snail Planorbis corneus, dissected together with the buccal ganglia, performs rhythmic feeding movements. Radula movements and the electrical activity in various nerves of buccal ganglia were recorded in such a preparation. The cycle of radula movements consisted of three phases: quiescence (Q), protraction (P) and retraction (R). The activity in the radular nerve

Yu. I. Arshavsky; T. G. Deliagina; E. S. Meizerov; G. N. Orlovsky; Yu. V. Panchin

1988-01-01

28

The Effect of Aquatic Plant Abundance on Shell Crushing Resistance in a Freshwater Snail  

E-print Network

-occurs with a specialized snail crushing fish. Aquatic snails are excellent model systems to study anti- predator mechanismThe Effect of Aquatic Plant Abundance on Shell Crushing Resistance in a Freshwater Snail Johel, Baja California Sur, Me´xico Abstract Most of the shell material in snails is composed of calcium

Johnson, Steven G.

29

The shell matrix of the pulmonate land snail Helix aspersa maxima.  

PubMed

In mollusks, the shell mineralization process is controlled by an array of proteins, glycoproteins and polysaccharides that collectively constitute the shell matrix. In spite of numerous researches, the shell protein content of a limited number of model species has been investigated. This paper presents biochemical data on the common edible land snail Helix aspersa maxima, a model organism for ecotoxicological purposes, which has however been poorly investigated from a biomineralization viewpoint. The shell matrix of this species was extracted and analyzed biochemically for functional in vitro inhibition assay, for amino acid and monosaccharides compositions. The matrix was further analyzed on 1 and 2D gels and short partial protein sequences were obtained from 2D gel spots. Serological comparisons were established with a set of heterologous antibodies, two of which were subsequently used for subsequent immunogold localization of matrix components. Our data suggest that the shell matrix of Helix aspersa maxima may differ widely from the shell secretory repertoire of the marine mollusks studied so far, such as the gastropod Haliotis or the pearl oyster Pinctada. In particular, most of the biochemical properties generally attributed to soluble shell matrices, such as calcium-binding capability, or the capacity to interfere in vitro with the precipitation of calcium carbonate or to inhibit the precipitation of calcium carbonate, were not recorded with this matrix. This drastic change in the biochemical properties of the landsnail shell matrix puts into question the existence of a unique molecular model for molluscan shell formation, and may be related to terrestrialisation. PMID:22198121

Pavat, Céline; Zanella-Cléon, Isabelle; Becchi, Michel; Medakovic, Davorin; Luquet, Gilles; Guichard, Nathalie; Alcaraz, Gérard; Dommergues, Jean-Louis; Serpentini, Antoine; Lebel, Jean-Marc; Marin, Frédéric

2012-04-01

30

Camouflaged or tanned: plasticity in freshwater snail pigmentation.  

PubMed

By having phenotypically plastic traits, many organisms optimize their fitness in response to fluctuating threats. Freshwater snails with translucent shells, e.g. snails from the Radix genus, differ considerably in their mantle pigmentation patterns, with snails from the same water body ranging from being completely dark pigmented to having only a few dark patterns. These pigmentation differences have previously been suggested to be genetically fixed, but we propose that this polymorphism is owing to phenotypic plasticity in response to a fluctuating environment. Hence, we here aimed to assess whether common stressors, including ultraviolet radiation (UVR) and predation, induce a plastic response in mantle pigmentation patterns of Radix balthica. We show, in contrast to previous studies, that snails are plastic in their expression of mantle pigmentation in response to changes in UVR and predator threats, i.e. differences among populations are not genetically fixed. When exposed to cues from visually hunting fish, R. balthica increased the proportion of their dark pigmentation, suggesting a crypsis strategy. Snails increased their pigmentation even further in response to UVR, but this also led to a reduction in pattern complexity. Furthermore, when exposed to UVR and fish simultaneously, snails responded in the same way as in the UVR treatment, suggesting a trade-off between photoprotection and crypsis. PMID:24046875

Ahlgren, Johan; Yang, Xi; Hansson, Lars-Anders; Brönmark, Christer

2013-10-23

31

Camouflaged or tanned: plasticity in freshwater snail pigmentation  

PubMed Central

By having phenotypically plastic traits, many organisms optimize their fitness in response to fluctuating threats. Freshwater snails with translucent shells, e.g. snails from the Radix genus, differ considerably in their mantle pigmentation patterns, with snails from the same water body ranging from being completely dark pigmented to having only a few dark patterns. These pigmentation differences have previously been suggested to be genetically fixed, but we propose that this polymorphism is owing to phenotypic plasticity in response to a fluctuating environment. Hence, we here aimed to assess whether common stressors, including ultraviolet radiation (UVR) and predation, induce a plastic response in mantle pigmentation patterns of Radix balthica. We show, in contrast to previous studies, that snails are plastic in their expression of mantle pigmentation in response to changes in UVR and predator threats, i.e. differences among populations are not genetically fixed. When exposed to cues from visually hunting fish, R. balthica increased the proportion of their dark pigmentation, suggesting a crypsis strategy. Snails increased their pigmentation even further in response to UVR, but this also led to a reduction in pattern complexity. Furthermore, when exposed to UVR and fish simultaneously, snails responded in the same way as in the UVR treatment, suggesting a trade-off between photoprotection and crypsis. PMID:24046875

Ahlgren, Johan; Yang, Xi; Hansson, Lars-Anders; Brönmark, Christer

2013-01-01

32

FRESHWATER SNAILS (MOLLUSCA: GASTROPODA) OF NORTH AMERICA  

EPA Science Inventory

Freshwater gastropod mollusks are represented in North America (north of Mexico) by 15 families, 78 genera and, as treated in this manual, 499 species. They are grouped into two large subclasses, the gill-breathing, operculated Prosobranchia and the lung-breathing, non-operculate...

33

Occurrence of Diplostomum pseudospathaceum Niewiadomska, 1984 and D. mergi Dubois, 1932 (Digenea: Diplostomidae) in Danish freshwater snails: ecological and molecular data.  

PubMed

Freshwater pulmonate snails from three locations in Lake Furesø north of Copenhagen were screened for infection with furcocercariae (by shedding in the laboratory) and recovered parasite larvae were diagnosed by molecular methods (by performing PCR of rDNA and sequencing the internal transcribed spacer [ITS] region). Overall prevalence of infection in snails was 2%. Recovered cercariae from Lymnaea stagnalis (Linnaeus) were diagnosed as Diplostomum pseudospathaceum Niewiadomska, 1984 (prevalence 4%) and cercariae from Radix balthica (Linnaeus) as D. mergi (Dubois, 1932) (prevalence 2%). Pathogen-free rainbow trout were then exposed to isolated cercariae and infection success and site location of metacercariae in these fish were determined. Infection experiments confirmed that both species could infect rainbow trout with the eye lens as infection site for the metacercarial stage although infection success differed. Combination of molecular and biological assays may contribute to improvement of our knowledge on diagnosis, distribution and biology of diplostomids in fish. PMID:23724738

Haarder, Simon; Jørgensen, Kasper; Kania, Per Walter; Skovgaard, Alf; Buchmann, Kurt

2013-05-01

34

The maintenance of hybrids by parasitism in a freshwater snail.  

PubMed

Hybrids have often been labelled evolutionary dead-ends due to their lower fertility and viability. However, there is growing awareness that hybridisation between different species may play a constructive role in animal evolution as a means to create variability. Thus, hybridisation and introgression may contribute to adaptive evolution, for example with regards to natural antagonists (parasites, predators, competitors) and adaptation to local environmental conditions. Here we investigated whether parasite intensity contributes to the continuous recreation of hybrids in 74 natural populations of Melanopsis, a complex of freshwater snails with three species. We also examined, under laboratory conditions, whether hybrids and their parental taxa differ in their tolerance of low and high temperatures and salinity levels. Infections were consistently less prevalent in males than in females, and lower in snails from deeper habitats. Infection prevalence in hybrids was significantly lower than in the parental taxa. Low hybrid infection rates could not be explained by sediment type, snail density or geographic distribution of the sampling sites. Interestingly, infected hybrid snails did not show signs of parasite-induced gigantism, whereas all parental taxa did. We found that hybrids mostly coped with extreme temperatures and salinity levels as well as their parental taxa did. Taken together, our results suggest that Melanopsis hybrids perform better in the presence of parasites and environmental stress. This may explain the widespread and long-term occurrence of Melanopsis hybrids as evidenced by paleontological and biogeographic data. Hybridisation may be an adaptive host strategy, reducing infection rates and resisting gigantism. PMID:25173837

Guttel, Yonathan; Ben-Ami, Frida

2014-11-01

35

Efficacy of Euphorbia hirta latex as plant derived molluscicides against freshwater snails.  

PubMed

The toxic effect of binary and tertiary combinations of Euphorbia hirta Linn latex powder with other plant molluscicidal compounds, were evaluated against the freshwater snails Lymnaea (Radix) acuminata and Indoplanorbis exustus in pond. These combinations showed significant time and dose dependent effect against both the snails. These compounds at higher doses were also lethal to freshwater fish Channa punctatus (Bloch) (Channidae {Ophicephalidae}), which shares the habitat with these snails, but the LC90 (24h) doses of snails have no apparent killing properties in fish populations when treated in mixed population of snails and fish. PMID:21537758

Yadav, Ram P; Singh, Ajay

2011-01-01

36

Multiple paternity in the freshwater snail, Potamopyrgus antipodarum  

PubMed Central

Mating multiply may incur costs, such as exposure to predators and to sexually transmitted diseases. Nevertheless, it may be favored, in spite of these costs, as a way to increase the genetic diversity of offspring through fertilization by multiple males. Here, we tested for multiple paternity in a freshwater snail (Potamopyrgus antipodarum), which is host to several species of sterilizing trematode worms. Using microsatellites markers, we found multiple paternity in two different snail populations, with as many as seven males fertilizing a single female. In addition, high evenness of sire fertilization was found within individual broods. Multiple paternity can occur for a variety of reasons; however, given that these populations experience high risk of infection by a sterilizing trematode, one potential explanation may be that multiple paternity and high evenness of sire fertilizations increase the chances of the production of parasite-resistant offspring. PMID:23301182

Soper, Deanna M; Delph, Lynda F; Lively, Curt M

2012-01-01

37

Angiostrongylus cantonensis : morphological and behavioral investigation within the freshwater snail Pomacea canaliculata  

Microsoft Academic Search

An infection with Angiostrongylus cantonensis, the main causative agent for human eosinophilic encephalitis, can be acquired through the consumption of the freshwater\\u000a snail Pomacea canaliculata. This snail also provides a suitable model to study the developmental morphology and behavior of A. cantonensis larvae, facilitated by the snail’s distinct lung structure. We used microanatomy for studying the natural appearance and\\u000a behavior

Shan Lv; Yi Zhang; He-Xiang Liu; Chao-Wei Zhang; Peter Steinmann; Xiao-Nong Zhou; Jürg Utzinger

2009-01-01

38

Clonal diversity driven by parasitism in a freshwater snail.  

PubMed

One explanation for the widespread abundance of sexual reproduction is the advantage that genetically diverse sexual lineages have under strong pressure from virulent coevolving parasites. Such parasites are believed to track common asexual host genotypes, resulting in negative frequency-dependent selection that counterbalances the population growth-rate advantage of asexuals in comparison with sexuals. In the face of genetically diverse asexual lineages, this advantage of sexual reproduction might be eroded, and instead sexual populations would be replaced by diverse assemblages of clonal lineages. We investigated whether parasite-mediated selection promotes clonal diversity in 22 natural populations of the freshwater snail Melanoides tuberculata. We found that infection prevalence explains the observed variation in the clonal diversity of M. tuberculata populations, whereas no such relationship was found between infection prevalence and male frequency. Clonal diversity and male frequency were independent of snail population density. Incorporating ecological factors such as presence/absence of fish, habitat geography and habitat type did not improve the predictive power of regression models. Approximately 11% of the clonal snail genotypes were shared among 2-4 populations, creating a web of 17 interconnected populations. Taken together, our study suggests that parasite-mediated selection coupled with host dispersal ecology promotes clonal diversity. This, in return, may erode the advantage of sexual reproduction in M. tuberculata populations. PMID:24118641

Dagan, Y; Liljeroos, K; Jokela, J; Ben-Ami, F

2013-11-01

39

Carbaryl induced alterations in the reproduction and metabolism of freshwater snail Lymnaea acuminata  

Microsoft Academic Search

When the freshwater snail Lymnaea acuminata was exposed to sub-lethal doses (2.0, 5.0, and 8.0mg\\/L) of carbaryl, fecundity was significantly reduced and even stopped at higher sub-lethal doses and altered metabolic activity in the body tissue of the snail was observed. The change from aerobic to anaerobic metabolism results in lesser energy production in the body tissues of the snails,

Pankaj Kumar Tripathi; Ajay Singh

2004-01-01

40

TREMATODE INFECTIONS OF THE FRESHWATER SNAIL FAMILY THIARIDAE IN THE KHEK RIVER, THAILAND  

Microsoft Academic Search

The freshwater snail family Thiaridae was studied at five different locations: water sources for the Khek River, Thailand. Snail samples were collected by hand using counts per unit of time sampling method between December 2004 and October 2005. The physico-chemi- cal quality of the water changed with the seasons and affected the sampling areas during both the dry season and

Wivitchuta Dechruksa; Duangduen Krailas; Suluck Ukong; Wasin Inkapatanakul; Tunyarut Koonchornboon

41

The influence of TCS on the growth and behavior of the freshwater snail, Physa acuta  

Microsoft Academic Search

Triclosan (TCS) is among the top 10 most persistent contaminants found in U.S. rivers, streams, lakes, and aquifers. Although TCS has not been found to be hazardous to humans, it can be toxic to aquatic environments and animals. The effects of TCS on growth rates and the locomotive behavior of the freshwater snail, Physa acuta, were studied by exposing snails

Jenell Brown; Melody J. Bernot; Randall J. Bernot

2012-01-01

42

Effect of the digenean parasite Proterometra macrostoma on host morphology in the freshwater snail Elimia livescens.  

PubMed

Parasitism can affect size in gastropods by altering the host's growth rate, but other morphological effects of parasitism have rarely been examined. In this study, the relationship between variation in host morphology and parasitism was examined in a population of the freshwater snail Elimia livescens. Differences were found in the morphology of snails infected with the digenean Proterometra macrostoma and uninfected snails. In order to differentiate between 2 hypotheses to explain these differences in morphology, snails were experimentally infected in the laboratory and several morphological traits were measured after 180 days. One hypothesis suggests that parasite-induced changes in shell development explain differences in morphology between infected and uninfected snails. The other hypothesis suggests that selective mortality of infected hosts explains the difference. In the experiment, differences were found between infected snails and uninfected snails in overall size but not in any measurements of shape. The short duration of the experiment relative to the duration of most infections may account for why field-infected snails differed in shape but experimentally infected snails did not. Parasite-induced changes in growth rate are the most likely explanation for the larger size of infected snails relative to uninfected snails. PMID:10780543

Krist, A C

2000-04-01

43

Comparison of snail density, standing stock, and body size between Caribbean karst wetlands and other freshwater ecosystems  

Microsoft Academic Search

Synthesizing data from multiple studies generates hypotheses about factors that affect the distribution and abundance of species\\u000a among ecosystems. Snails are dominant herbivores in many freshwater ecosystems, but there is no comprehensive review of snail\\u000a density, standing stock, or body size among freshwater ecosystems. We compile data on snail density and standing stock, estimate\\u000a body size with their quotient, and

Clifton B. RuehlJoel; Joel C. Trexler

2011-01-01

44

Body size--dependent gender role in a simultaneous hermaphrodite freshwater snail, Physa acuta  

Microsoft Academic Search

We examined whether gender role in the simultaneous hermaphrodite freshwater snail, Physa acuta, is determined by relative body size in a manner predicted by the size-advantage model. We observed the body-size combinations of pairs in the laboratory by using field-collected populations. Smaller individuals tended to play the \\

Kako Ohbayashi-Hodoki; Fumiko Ishihama; Masakazu Shimada

2004-01-01

45

Dragonfly predators influence biomass and density of pond snails.  

PubMed

Studies in lakes show that fish and crayfish predators play an important role in determining the abundance of freshwater snails. In contrast, there are few studies of snails and their predators in shallow ponds and marshes. Ponds often lack fish and crayfish but have abundant insect populations. Here we present the results of field surveys, laboratory foraging trials, and an outdoor mesocosm experiment, testing the hypothesis that insects are important predators of pulmonate snails. In laboratory foraging trials, conducted with ten species of insects, most insect taxa consumed snails, and larval dragonflies were especially effective predators. The field surveys showed that dragonflies constitute the majority of the insect biomass in fishless ponds. More focused foraging trials evaluated the ability of the dragonflies Anax junius and Pantala hymenaea to prey upon different sizes and species of pulmonate snails (Helisoma trivolvis, Physa acuta, and Stagnicola elodes). Anax junius consumed all three species up to the maximum size tested. Pantala hymenaea consumed snails with a shell height of 3 mm and smaller, but did not kill larger snails. P. acuta were more vulnerable to predators than were H. trivolvis or S. elodes. In the mesocosm experiment, conducted with predator treatments of A. junius, P. hymenaea, and the hemipteran Belostoma flumineum, insect predators had a pronounced negative effect on snail biomass and density. A. junius and B. flumineum reduced biomass and density to a similar degree, and both reduced biomass more than did P. hymenaea. Predators did not have a strong effect on species composition. A model suggested that A. junius and P. hymenaea have the largest effects on snail biomass in the field. Given that both pulmonate snails and dragonfly nymphs are widespread and abundant in marshes and ponds, snail assemblages in these water bodies are likely regulated in large part by odonate predation. PMID:17457617

Turner, Andrew M; Chislock, Michael F

2007-08-01

46

Epidemiology of cercarial stage of trematodes in freshwater snails from Chiang Mai province, Thailand  

PubMed Central

Objective To investigate the epidemiological situation of cercarial trematodes infection in freshwater snails from different water resources in Chiang Mai province, Thailand. Methods The snail specimens were collected from 13 districts of Chiang Mai province during April 2008 to February 2012. The prevalence of cercarial infection in snails was investigated using the crushing method. The drawing was done with the help of a camera lucida for the morphological study. Results A total of 2?479 snail individuals were collected and classified into 7 families, 11 genera, and 14 species, Among them, 8 snails species were found to be infected with an overall prevalence of 17.27% (428/2?479), which infected with nine groups of cercariae; gymnocephalous cercaria, strigea cercaria, megalurous cercaria, monostome cercaria, parapleurolophocercous cercaria (Haplorchis cercaria), pleurolophocercous cercaria, furcocercous cercaria (Transversotrema cercaria), xiphidiocercaria, and virgulate cercaria. The parapleurolophocercous cercaria was found to be the dominant type among the cercarial infection in the snails (64.25%). Conclusions The various species of snails found in the research location act as the intermediate hosts for the high prevalence of parasitic infection of many species of mammals. This work will provide new information on both the distribution and first intermediate host of trematodes. PMID:23620846

Chontananarth, Thapana; Wongsawad, Chalobol

2013-01-01

47

The freshwater snails (Gastropoda) of Iran, with descriptions of two new genera and eight new species  

PubMed Central

Abstract Using published records and original data from recent field work and revision of Iranian material of certain species deposited in the collections of the Natural History Museum Basel, the Zoological Museum Berlin, and Natural History Museum Vienna, a checklist of the freshwater gastropod fauna of Iran was compiled. This checklist contains 73 species from 34 genera and 14 families of freshwater snails; 27 of these species (37%) are endemic to Iran. Two new genera, Kaskakia and Sarkhia, and eight species, i.e., Bithynia forcarti, Bithynia starmuehlneri, Bithynia mazandaranensis, Pseudamnicola georgievi, Kaskakia khorrasanensis, Sarkhia sarabensis, Valvata nowsharensis and Acroloxus pseudolacustris are described as new to science; Ecrobia grimmi (Clessin & Dybowski, 1888), Heleobia dalmatica (Radoman, 1974) and Hippeutis complanatus (Linnaeus, 1758) are reported for the first time from Iran. Additional field work is highly desirable for a more appropriate evaluation of the extant freshwater snail biodiversity in Iran. PMID:22977349

Glöer, Peter; Peši?, Vladimir

2012-01-01

48

An overview of freshwater snails in Asia with main focus on Vietnam.  

PubMed

Freshwater snails have received much attention for their role as intermediate hosts for trematodes causing disease in people and animals such as schistosomiasis and various food-borne trematodes. While effective medical treatment exists for some of these diseases there is need for preventive measures to reduce transmission, e.g. control of intermediate hosts because transmission patterns are often complicated due to presence of reservoir final hosts. In order to implement control measures against the intermediate host snails with minimal impact on the freshwater ecosystems and their biodiversity, a profound knowledge on transmission patterns of the trematodes is required and this is partly related to distribution, habitat preferences, and seasonal variation in density of the intermediate host species. Identification of snail species can be problematic on the basis of morphological and anatomical characters alone as some species show morphological plasticity and similarly morphological differentiation of cercariae found in snails may be difficult and this could lead to biased perceptions of intermediate host spectra and transmission patterns. In this paper, we give an overview of the snail families and their medical and veterinary importance in Asia but with main focus on Vietnam. PMID:25149356

Madsen, H; Hung, N M

2014-12-01

49

Freshwater snails (Mollusca: Gastropoda) from the Commonwealth of Dominica with a discussion of their roles in the transmission of parasites  

Technology Transfer Automated Retrieval System (TEKTRAN)

We collected six species of freshwater snails from Dominica, including Biomphalaria kuhniana, Gundlachia radiata Helisoma (= Planorbella) trivolvis, Melanoides tuberculata, Neritina punctulata, and Physa marmorata. Our collections indicate that un-reported species such as Gundlachia radiata and Hel...

50

Functional diversity among predators of a freshwater snail imposes an adaptive trade-off for shell morphology  

Microsoft Academic Search

We explored how functional diversity among predators of the freshwater snail Physa creates an adaptive trade-off for the snail's shell morphology. Physid shells range continuously between elongate and rotund in overall shape. The protection conferred by alternative shell shapes depends on the mode of attack employed by predators. Predators attack Physa primarily through shell entry (by crayfish, Orconectes obscurus) and

Thomas J. DeWitt; Beren W. Robinson; David Sloan Wilson

2000-01-01

51

Scope for growth in a tropical freshwater snail -- Implications for monitoring sublethal toxic stressors  

SciTech Connect

Scope for growth (SfG), the difference between the energy input to an organism from its food and the output from respiratory metabolism, has been used as a bioassay for environmental stress in the temperate region. Here, the same technique was applied to a tropical freshwater snail, Brotia hainanensis (Thiaridae), to investigate whether the technique is applicable to biological systems at lower latitudes. In this study, the effects of copper and low pH on the SfG of the snails were examined. The results show that both copper and low pH can significantly reduce the SfG of individual snails through a decrease in the amount of energy absorbed, while the change in energy expenditure is not apparent. It was also found that the SfG assay is most informative at stress levels too low to be detected by the corresponding acute tests.

Lai, P.C.C.; Lam, P.K.S. [City Univ. of Hong Kong (Hong Kong). Dept. of Biology and Chemistry

1995-12-31

52

Prevalence of larval helminths in freshwater snails of the Kinmen Islands.  

PubMed

A survey of larval helminths in freshwater snails of Kinmen was conducted from 1986 to 1987. Parasitological examinations of a total of 726 live snails collected from 25 loci revealed that 20 of 80 Bithynia fuchsiana were infected with metacercariae of Echinostoma gotoi and 36 with metacercariae of other echinostomes. Among 57 Radix auricularia swinhoei snails, 27 were infected with echinostomes and eight with metacercariae of other flukes. Of 20 Cipangopaludina chinensis, 18 were found with larvae of echinostomes. Larval trematodes were also found in three of 37 Austropeplea ollula and two of 87 Gyraulus spirillus. Third-stage larvae of Parastrongylus cantonensis were found in Ampullarius canaliculatus (5/103), Sinotaia quadrata (20/141), Hippeutis umbilicalis cantori (1/70) and Gyraulus spirillus (2/87). Segmentina hemisphaerula were not infected. Cercariae of Centrocestus formosanus, Haplorchis pumilio and a xiphidiocercaria were found in three, two and two specimens, respectively, of 37 Thiara tuberculata. PMID:8132969

Chao, D; Wang, L C; Huang, T C

1993-12-01

53

Variation In Metabolic Cost of Embryonic Development of the Freshwater Snail, Phsya sp  

Microsoft Academic Search

Embryos of the freshwater snail Physa sp. complete their development within an egg capsule and hatch as juveniles. To estimate the energetic cost of development, oxygen consumption rates of egg masses were monitored from deposition to hatching. Oxygen consumption increased during development (r2=O.173, p\\u000aOriginally presented in the John Wesley Powell Student Research Conference - April 14, 2007 and used

Hall Andrew

2007-01-01

54

Failure of transmission of low-pathogenic avian influenza virus between Mallards and freshwater snails: an experimental evaluation.  

PubMed

In aquatic bird populations, the ability of avian influenza (AI) viruses to remain infectious in water for extended periods provides a mechanism that allows viral transmission to occur long after shedding birds have left the area. However, this also exposes other aquatic organisms, including freshwater invertebrates, to AI viruses. Previous researchers found that AI viral RNA can be sequestered in snail tissues. Using an experimental approach, we determined whether freshwater snails (Physa acuta and Physa gyrina) can infect waterfowl with AI viruses by serving as a means of transmission between infected and naïve waterfowl via ingestion. In our first experiment, we exposed 20 Physa spp. snails to an AI virus (H3N8) and inoculated embryonated specific pathogen-free (SPF) chicken eggs with the homogenized snail tissues. Sequestered AI viruses remain infectious in snail tissues; 10% of the exposed snail tissues infected SPF eggs. In a second experiment, we exposed snails to water contaminated with feces of AI virus-inoculated Mallards (Anas platyrhynchos) to evaluate whether ingestion of exposed freshwater snails was an alternate route of AI virus transmission to waterfowl. None of the immunologically naïve Mallards developed an infection, indicating that transmission via ingestion likely did not occur. Our results suggest that this particular trophic interaction may not play an important role in the transmission of AI viruses in aquatic habitats. PMID:24502718

Oesterle, Paul T; Huyvaert, Kathryn P; Orahood, Darcy; Mooers, Nicole; Sullivan, Heather; Franklin, Alan B; Root, J Jeffrey

2013-10-01

55

Activation of the immune defence of the freshwater snail Lymnaea stagnalis by different immune elicitors.  

PubMed

Understanding the outcomes of host-parasite interactions in nature is in high demand as parasites and pathogens are important for several ecological and evolutionary processes. Ecological immunology (ecoimmunology) has a key role in reaching this goal because immune defence is the main physiological barrier against infections. To date, ecoimmunological studies largely lean on measuring constitutive immune defences (components of defence that are always active). However, understanding the role of inducible components of immune function is important as the immune system is largely an inducible defence. Measuring such defences can be complicated as different parasites may activate different immune cascades, and expression of different immune traits may not be independent. We examined the suitability of different immune activation techniques for the freshwater snail Lymnaea stagnalis. By experimentally challenging snails with different immune elicitors [injection with snail saline (i.e. wounding), lyophilized Escherichia coli cells, lyophilized Micrococcus lysodeikticus cells, healthy snail gonad, and trematode-infected snail gonad; maintenance in microorganism-enriched water] and measuring phenoloxidase-like and antibacterial activity of their haemolymph, we found increased immune activity against some immune elicitors, but also decreased activity. Our findings suggest potentially complicated relationships among immune traits, and propose suitable techniques for ecological studies in this study system. PMID:23842628

Seppälä, Otto; Leicht, Katja

2013-08-01

56

Predator-Induced Morphological Plasticity Across Local Populations of a Freshwater Snail  

PubMed Central

The expression of anti-predator adaptations may vary on a spatial scale, favouring traits that are advantageous in a given predation regime. Besides, evolution of different developmental strategies depends to a large extent on the grain of the environment and may result in locally canalized adaptations or, alternatively, the evolution of phenotypic plasticity as different predation regimes may vary across habitats. We investigated the potential for predator-driven variability in shell morphology in a freshwater snail, Radix balthica, and whether found differences were a specialized ecotype adaptation or a result of phenotypic plasticity. Shell shape was quantified in snails from geographically separated pond populations with and without molluscivorous fish. Subsequently, in a common garden experiment we investigated reaction norms of snails from populations' with/without fish when exposed to chemical cues from tench (Tinca tinca), a molluscivorous fish. We found that snails from fish-free ponds had a narrow shell with a well developed spire, whereas snails that coexisted with fish had more rotund shells with a low spire, a shell morphology known to increase survival rate from shell-crushing predators. The common garden experiment mirrored the results from the field survey and showed that snails had similar reaction norms in response to chemical predator cues, i.e. the expression of shell shape was independent of population origin. Finally, we found significant differences for the trait means among populations, within each pond category (fish/fish free), suggesting a genetic component in the determination of shell morphology that has evolved independently across ponds. PMID:21818264

Brönmark, Christer; Lakowitz, Thomas; Hollander, Johan

2011-01-01

57

Diet alters delayed selfing, inbreeding depression, and reproductive senescence in a freshwater snail.  

PubMed

Reproductive success is a critical fitness attribute that is directly influenced by resource availability. Here, we investigate the effects of diet-based resource availability on three interrelated aspects of reproductive success: a change in mating system based on mate availability, consequent inbreeding depression, and the deterioration of reproductive efficiency with age (senescence). We employed a factorial experimental design using 22 full-sib families of the hermaphroditic freshwater snail Physa acuta to explore these interactions. Individual snails were reared in one of two mate-availability treatments (isolated [selfing] or occasionally paired [outcrossing]) and one of two diet treatments (boiled lettuce or Spirulina, an algae that is rich in protein, vitamins, and minerals). Spirulina-fed snails initiated reproduction at a 13% earlier age and 7% larger size than lettuce-fed snails. Spirulina also resulted in a 30% reduction in the time delay before selfing. Compared to lettuce, a diet of Spirulina increased inbreeding depression by 52% for egg hatching rate and 64% for posthatching juvenile survival. Furthermore, Spirulina led to a 15-fold increase in the rate of reproductive senescence compared with a diet of lettuce. These transgenerational, interactive effects of diet on inbreeding depression and reproductive senescence are discussed in the context of diet-induced phenotypic plasticity. PMID:25165532

Auld, Josh R; Henkel, John F

2014-07-01

58

Plasticity as Phenotype: G x E Interaction in a Freshwater Snail  

NASA Astrophysics Data System (ADS)

Plasticity in morphological development allows species to accommodate environmental variation experienced during growth; however, genetic variation for phenotypic plasticity per se has been relatively under-studied. We utilized the well-documented plastic response of shell development to predator cues in a freshwater snail to quantify genetic variation for plasticity in growth rate and shell shape. Field-caught pairs of snails reproduced in the laboratory to create families of full siblings, which were then divided and allowed to grow in control and predator cue treatments. Predator (crayfish) cues had significant effects on both size-corrected growth rate and shell shape; family identity also significantly affected both final shell shape and growth rate. The interaction between predator treatment and family identity significantly affected snail growth rate but not final shell shape, suggesting genetic variation in the plastic response to predator cues for a physiological variable (growth rate) but not for a variable known to mechanically reduce the risk of predation (shell shape), at least in this population of snails. The possibility that risk of multiple modes of predation (i.e., both fish and crayfish) in some populations might maintain genetic variation in morphological plasticity is discussed.

Brunkow, P. E.; Calloway, S. A.

2005-05-01

59

Factors and processes shaping the population structure and distribution of genetic variation across the species range of the freshwater snail radix balthica (Pulmonata, Basommatophora)  

PubMed Central

Background Factors and processes shaping the population structure and spatial distribution of genetic diversity across a species' distribution range are important in determining the range limits. We comprehensively analysed the influence of recurrent and historic factors and processes on the population genetic structure, mating system and the distribution of genetic variability of the pulmonate freshwater snail Radix balthica. This analysis was based on microsatellite variation and mitochondrial haplotypes using Generalised Linear Statistical Modelling in a Model Selection framework. Results Populations of R. balthica were found throughout North-Western Europe with range margins marked either by dispersal barriers or the presence of other Radix taxa. Overall, the population structure was characterised by distance independent passive dispersal mainly along a Southwest-Northeast axis, the absence of isolation-by-distance together with rather isolated and genetically depauperated populations compared to the variation present in the entire species due to strong local drift. A recent, climate driven range expansion explained most of the variance in genetic variation, reducing at least temporarily the genetic variability in this area. Other factors such as geographic marginality and dispersal barriers play only a minor role. Conclusions To our knowledge, such a population structure has rarely been reported before. It might nevertheless be typical for passively dispersed, patchily distributed taxa (e.g. freshwater invertebrates). The strong local drift implied in such a structure is expected to erode genetic variation at both neutral and coding loci and thus probably diminish evolutionary potential. This study shows that the analysis of multiple factors is crucial for the inference of the processes shaping the distribution of genetic variation throughout species ranges. PMID:21599918

2011-01-01

60

Secondary production and diet of an invasive snail in freshwater wetlands: implications for resource utilization and competition  

Microsoft Academic Search

Invasive species can monopolize resources and thus dominate ecosystem production. In this study we estimated secondary production\\u000a and diet of four populations of Pomacea canaliculata, a freshwater invasive snail, in wetlands (abandoned paddy, oxbow pond, drainage channel, and river meander) in monsoonal\\u000a Hong Kong (lat. 22°N). Apple snail secondary production (ash-free dry mass [AFDM]) ranged from 165.9 to 233.3 g m?2 year?1, and

King Lun Kwong; David Dudgeon; Pak Ki Wong; Jian-Wen Qiu

2010-01-01

61

Predation and control of laboratory populations of the snail Biomphalaria glabrata by the freshwater prawn Macrobrachium rosenbergii.  

PubMed

Laboratory experiments were conducted on predation by the giant freshwater prawn, Macrobrachium rosenbergii, on Biomphalaria glabrata, a snail intermediate host of human schistosomiasis. Prawns greater than 22 mm carapace length could consume snails of any size. Smaller prawns exhibited a size-specific upper limit on the size of snail they could kill. Below the maximum size of prey consumed, little selectivity for prey size was demonstrated. All prawns heavier than 2.5 g killed the largest size of snail offered (16 mm diameter). Consumption, in terms of the numbers of snails killed, and the snails' wet weight and percentage of prawn body weight eaten per day, increased with prawn size. Large prawns consumed snails at a high rate (39% of body weight per day). Population experiments demonstrated that a prawn of 25 mm carapace length could eliminate 95% of a population of 80 snails in a 20-1 aquarium within 20 days and all snails by day 40. A prawn of 15 mm carapace length could not eliminate all snails. Large snails (24% of the initial population) had some protection from predation because of their size. Although the snails bred continuously, no snails were able to recruit to these populations in the presence of small prawns. In contrast, snail populations in control aquaria without prawns expanded to a mean of 919 snails by the end of the experiment (day 70). Since M. rosenbergii are voracious predators on B. glabrata, exhibit considerable habitat overlap with the snail prey, and are likely to treat snails as highly preferred food, further experimentation on these prawns in the context of biological control of schistosomiasis is warranted. The ready availability of prawns through established prawn hatcheries and the synergistic use of these prawns in aquaculture may ensure the reliability of stocking procedures and meet the standards of availability and cost-effectiveness required of a biological control agent. Polyculture of Macrobrachium with fin fish (Tilapia) indicates that these prawns may be a particularly useful control agent in aquacultural environments. PMID:2260905

Roberts, J K; Kuris, A M

1990-08-01

62

Development of the Statocyst in the Freshwater Snail Biomphalaria Glabrata (Pulmonata, Basommatophora)  

NASA Technical Reports Server (NTRS)

The development of the statocyst of the freshwater snail Biomphalaria glabrata has been examined from embryo to adult. Special emphasis was put on the growth of the statoconia in the statocysts. In the statocysts of embryonic snails (90-120 h after oviposition) there is not a single statolith but an average of 40-50 statoconia per statocyst. The number of statoconia increases to 385-400 when the snails reach a shell diameter of 4 mm and remains relatively constant thereafter, irrespective of shell size. Small statoconia are found in supporting cells, which suggests that the statoconia are produced within these cells. The average diameter of statoconia and the total mass of statoconia increase with increasing shell diameter. The average number of large statoconia (diameter greater than 7 micrometers) per statocyst continues to increase from 2 to 10 mm animals while the number of small ones (diameter less than 4 micrometers) initially rises and then decreases after 4 mm. These results demonstrate continuous growth of the statoconia in the cyst lumen of Biomphalaria. The single statoconia vibrate in a regular pattern in vivo, indicating beating of the statocyst cilia. The statoconia sink under the influence of gravity to load and stimulate receptor cells which are at the bottom. The length of cilia and the size of statocyst gradually increase as the animal grows. However, the increase in the volume of the statocyst is relatively small compared with the increase in body weight during normal development.

Gao, Wenyuan; Wiederhold, Michael; Hejl, Robert

1997-01-01

63

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

SciTech Connect

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.

Jugdaohsingh, R.; Thompson, R.P.H.; Powell, J.J. [St. Thomas Hospital, London (United Kingdom)] [St. Thomas Hospital, London (United Kingdom); Campbell, M.M.; Mccrohan, C.R.; White, K.N. [Univ. of Manchester (United Kingdom). School of Biological Sciences] [Univ. of Manchester (United Kingdom). School of Biological Sciences

1998-09-01

64

Understanding the regulation of estivation in a freshwater snail through iTRAQ-based comparative proteomics.  

PubMed

The apple snail Pomacea canaliculata is a freshwater gastropod with a remarkable ability to withstand seasonal or unpredictable dry conditions by entering estivation. Studies of P. canaliculata using conventional biochemical and the individual gene approaches have revealed the expressional changes of several enzymes and antioxidative genes in response to estivation and arousal. In this study, we applied iTRAQ-coupled two-dimensional LC-MS/MS to identify and quantify the global protein expression during the estivation and arousal of P. canaliculata. A total of 1040 proteins were identified, among which 701 proteins were quantified and compared across four treatments (i.e., control, active snails; short-term estivation, 3 days of exposure to air; prolonged estivation, 30 days of exposure to air; and arousal, 6 h after resubmergence in water) revealing 53 differentially expressed proteins. A comparison of protein expression profiles across treatments indicated that the proteome of this species was very insensitive to initial estivation, with only 9 proteins differentially expressed as compared with the control. Among the 9 proteins, the up-regulations of two immune related proteins indicated the initial immune response to the detection of stress cues. Prolonged estivation resulted in many more differentially expressed proteins (47 compared with short-term estivation treatment), among which 16 were down-regulated and 31 were up-regulated. These differentially expressed proteins have provided the first global picture of a shift in energy usage from glucose to lipid, prevention of protein degradation and elevation of oxidative defense, and production of purine for uric acid production to remove toxic ammonia during prolonged estivation in a freshwater snail. From prolonged estivation to arousal, only 6 proteins changed their expression level, indicating that access to water and food alone is not a necessary condition to reactivate whole-sale protein expression. A comparison with hibernation and diapause revealed many similar molecular mechanisms of hypometabolic regulation across the animal kingdom. PMID:24088062

Sun, Jin; Mu, Huawei; Zhang, Huoming; Chandramouli, Kondethimmanahalli H; Qian, Pei-Yuan; Wong, Chris Kong Chu; Qiu, Jian-Wen

2013-11-01

65

Trematode infections of the freshwater snail family Thiaridae in the Khek River, Thailand.  

PubMed

The freshwater snail family Thiaridae was studied at five different locations: water sources for the Khek River, Thailand. Snail samples were collected by hand using counts per unit of time sampling method between December 2004 and October 2005. The physico-chemical quality of the water changed with the seasons and affected the sampling areas during both the dry season and the flood season. A total of 9,568 snail samples comprised of 14 species were found. These were 284 Tarebia granifera, 24 Melanoides tuberculata, 86 Thiara scabra, 3,295 Paracrostoma pseudosulcospira pseudosulcospira, 736 P. paludiformis paludiformis, 3,266 P. paludiformis dubiosa, 117 P. morrisoni, 304 Brotia (Brotia) binodosa binodosa, 1,250 B. (Brotia) microsculpta, 146 B. (Senckenbergia) wykoffi, 1 B. (Brotia) pagodula, 5 B. (Brotia) binodosa spiralis, 5 B. (Brotia) insolita and 49 B. (Brotia) manningi. The cercariae were investigated using shedding and crushing methods where they were categorized into two types and five species. The first type, Parapleurolophocercous cercariae, were comprised of Haplorchis pumilio Looss, 1899 and Centrocestus formosanus Nishigori, 1924. The second type, Xiphidiocercariae were comprised of Acanthatrium hitaense Koga, 1953, Loxogenoides bicolor Kaw, 1945 and Haematoloechus similis Looss, 1899. The cercarial infection rates in the above 5 species were 0.1% (5:9,568), 0.2% (15:9,568), 0.3% (24:9,568), 0.4% (37:9,568) and 0.1% (5:9,568), respectively. Five species of snails were susceptible to trematode infections. They were T. granifera, M. tuberculata, T. scabra, P. paludiformis paludiformis and B. (Senckenbergia) wykoffi; infections were found in 26.1% (74:284), 33.3% (8:24), 1.2% (1:86), 0.3% (2:736) and 0.7% (1:146), respectively. PMID:18613543

Dechruksa, Wivitchuta; Krailas, Duangduen; Ukong, Suluck; Inkapatanakul, Wasin; Koonchornboon, Tunyarut

2007-11-01

66

Detection of Neorickettsia risticii from various freshwater snail species collected from a district irrigation canal in Nevada County, California.  

PubMed

This study investigated the role of a district irrigation canal in Nevada County, California, USA, as the point source of infection for Neorickettsia risticii, causative agent of equine neorickettsiosis (EN). A total of 568 freshwater snails comprising Juga spp., Planorbella subcrenata (Carpenter, 1857) (Rough Rams-horn), Physella virgata (Gould, 1855) (Protean Physa) and feces from three horses with EN were collected and tested for N. risticii by real-time PCR. A total of four freshwater snails tested PCR positive for N. risticii. Phylogenetic analysis showed 99.8-100% homology between the different snail and horse N. risticii isolates. This study represents the first report of infection with N. risticii in Planorbella subcrenata and suggests that the irrigation canal was the aquatic environment responsible for the spread of N. risticii. PMID:23566936

Pusterla, Nicola; Hagerty, Daniel; Mapes, Samantha; Vangeem, Josh; Groves, Lindsey T; Dinucci, Mario; Fielding, Langdon C; Higgins, Jill C

2013-08-01

67

Toxicity evaluation of ammonium sulphate and urea to three developmental stages of freshwater snails.  

PubMed

Studies were performed to evaluate the toxic effects of ammonium sulphate and urea (chemical fertilizers currently applied in ricelands of Cameroon) against eggs, juveniles, and adults of two species of freshwater snails (Helisoma trivolvis and Biomphalaria havanensis). Results obtained from ammonium sulphate tests indicated 24-h LC50 values of 558 mg/L and 669 mg/L for eggs; 393 mg/L and 526 mg/L for juveniles, and 701 mg/L and 657 mg/L for adults of H. trivolvis and B. havanensis, respectively. Similar analysis with urea revealed LC50 values of 14,241 mg/L and 13,532 mg/L for eggs; 18,255 mg/L and 24,504 mg/L for juveniles and 30,060 mg/L and 26,024 mg/L for adults of H. trivolvis and B. havanensis, respectively. Following 48 h exposure, the concentrations of ammonium sulphate killing 100% of snails were 1,250 mg/L and 1,000 mg/L for the adults of H. trivolvis and of B. havanensis, respectively. Those of urea were computed to be 25,000 mg/L for H. trivolvis and 35,000 mg/L for B. havanensis. In rice culture in Cameroon, these fertilizers are applied at doses of 100 kg/ha (ammonium sulphate) and of 150 kg/ha (urea); hence, the above found concentrations lethal to snails appeared to be 10 to 13 times (ammonium sulphate) and to be 165 to 235 times (urea) higher assuming an average water depth of 10 cm in these ricefields. Therefore, the use of ammonium sulphate and urea as chemical fertilizers in ricelands of the Republic of Cameroon might adversely affect the survival of freshwater snails only in the case of spills or of stressful environmental conditions. Under normal laboratory conditions, both chemicals show a low molluscicidal activity with urea being about 25 to 35 times less potent than ammonium sulphate. PMID:1953026

Tchounwou, P B; Englande, A J; Malek, E A

1991-09-01

68

Response to Phosphorus Limitation Varies among Lake Populations of the Freshwater Snail Potamopyrgus antipodarum  

PubMed Central

Local adaptation – typically recognized as higher values of fitness-related traits for native vs. non-native individuals when measured in the native environment - is common in natural populations because of pervasive spatial variation in the intensity and type of natural selection. Although local adaptation has been primarily studied in the context of biotic interactions, widespread variation in abiotic characteristics of environments suggests that local adaptation in response to abiotic factors should also be common. Potamopyrgus antipodarum, a freshwater New Zealand snail that is an important model system for invasion biology and the maintenance of sexual reproduction, exhibits local adaptation to parasites and rate of water flow. As an initial step to determining whether P. antipodarum are also locally adapted to phosphorus availability, we examined whether populations differ in their responses to phosphorus limitation. We found that field-collected juvenile P. antipodarum grew at a lower rate and reached an important size threshold more slowly when fed a relatively low vs. a relatively high- phosphorus diet. We also detected significant across-population variation in individual growth rate. A marginally significant population-by-dietary phosphorus interaction along with a two-fold difference across populations in the extent of suppression of growth by low phosphorus suggests that populations of P. antipodarum may differ in their response to phosphorus limitation. Local adaptation may explain this variation, with the implication that snails from lakes with relatively low phosphorus availability should be less severely affected by phosphorus limitation than snails from lakes with higher phosphorus availability. PMID:24454936

Krist, Amy C.; Kay, Adam D.; Larkin, Katelyn; Neiman, Maurine

2014-01-01

69

Toxicological effects and oxidative stress responses in freshwater snail, Lanistes carinatus, following exposure to chlorpyrifos.  

PubMed

Chlorpyrifos is a widely used organophosphorous pesticide in agriculture and environmental health. Laboratory studies of chlorpyrifos have revealed acute lethal toxicity at very low concentration (96-h LC50) of 0.39?gL(-1) to the freshwater snail, Lanistes carinatus. Acetylcholinesterase (AChE) inhibition progressed and reached 52% and 78% of the control after 28-d exposure to 0.09 and 0.29?gL(-1) chlorpyrifos, respectively. Catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities increased in comparison to control group in the first period of exposure (7-21d), then decreased relative to the control in the second period of exposure (21-28d). A significant (p<0.05) glutathione (GSH) depletion was observed in snails exposed to 0.09 and 0.29?gL(-1) in comparison to the control, whereas malondialdehyde (MDA) content gradually increased in a dose-dependent manner. This study showed that alterations in antioxidant enzyme activities along with depletion of GSH content and elevation of MDA content can be used as biomarkers in environmental assessment programs. PMID:25800985

Khalil, Abdelmonem M

2015-06-01

70

DNA Barcode Identification of Freshwater Snails in the Family Bithyniidae from Thailand  

PubMed Central

Freshwater snails in the family Bithyniidae are the first intermediate host for Southeast Asian liver fluke (Opisthorchis viverrini), the causative agent of opisthorchiasis. Unfortunately, the subtle morphological characters that differentiate species in this group are not easily discerned by non-specialists. This is a serious matter because the identification of bithyniid species is a fundamental prerequisite for better understanding of the epidemiology of this disease. Because DNA barcoding, the analysis of sequence diversity in the 5’ region of the mitochondrial COI gene, has shown strong performance in other taxonomic groups, we decided to test its capacity to resolve 10 species/ subspecies of bithyniids from Thailand. Our analysis of 217 specimens indicated that COI sequences delivered species-level identification for 9 of 10 currently recognized species. The mean intraspecific divergence of COI was 2.3% (range 0-9.2 %), whereas sequence divergences between congeneric species averaged 8.7% (range 0-22.2 %). Although our results indicate that DNA barcoding can differentiate species of these medically-important snails, we also detected evidence for the presence of one overlooked species and one possible case of synonymy. PMID:24223896

Kulsantiwong, Jutharat; Prasopdee, Sattrachai; Ruangsittichai, Jiraporn; Ruangjirachuporn, Wipaporn; Boonmars, Thidarut; Viyanant, Vithoon; Pierossi, Paola; Hebert, Paul D. N.; Tesana, Smarn

2013-01-01

71

Inhibitory effect of naringin on microcystin-LR uptake in the freshwater snail Sinotaia histrica.  

PubMed

Gastropods are an important food source for aquatic animals, and have been demonstrated to transfer microcystin (MC) to higher trophic levels through the food web. In this study, we performed an oral administration experiment to evaluate whether naringin can inhibit MC-LR uptake in the freshwater snail Sinotaia histrica. We also observed the effect of MC-LR on the organizational pathology of the hepatopancreas in S. histrica. Following exposure to cells of Microcystis ichthyoblabe, S. histrica showed vacuolization and separation of the basal lamina from cells in the hepatopancreas. Initial treatment with 1mM naringin resulted in the prevention of MC-LR uptake rate by approximately 60% over 8days, whereas initial treatment with 10mM naringin suppressed microcystin uptake in 2days, despite an increase in MC-LR levels in the snail from days 5 to 8. With continuous treatment of 10mM naringin, the uptake prevention rate was 100%. Overall, we observed a strong inhibitory effect against MC-LR with naringin treatment. This study provides a potential mechanism to prevent the uptake of microcystin in the aquatic food web, thereby limiting its toxicity in cyanobacterial bloom-polluted areas where the environment can be controlled and may have further applications in the aquaculture of gastropods. PMID:25129375

Xie, Liqiang; Hanyu, Tamami; Futatsugi, Noriko; Komatsu, Masaharu; Steinman, Alan D; Park, Ho-Dong

2014-09-01

72

The evolution of reproductive isolation in a simultaneous hermaphrodite, the freshwater snail Physa  

PubMed Central

Background The cosmopolitan freshwater snail Physa acuta has recently found widespread use as a model organism for the study of mating systems and reproductive allocation. Mitochondrial DNA phylogenies suggest that Physa carolinae, recently described from the American southeast, is a sister species of P. acuta. The divergence of the acuta/carolinae ancestor from the more widespread P. pomilia appears to be somewhat older, and the split between a hypothetical acuta/carolinae/pomilia ancestor and P. gyrina appears older still. Results Here we report the results of no-choice mating experiments yielding no evidence of hybridization between gyrina and any of four other populations (pomilia, carolinae, Philadelphia acuta, or Charleston acuta), nor between pomilia and carolinae. Crosses between pomilia and both acuta populations yielded sterile F1 progeny with reduced viability, while crosses between carolinae and both acuta populations yielded sterile F1 hybrids of normal viability. A set of mate-choice tests also revealed significant sexual isolation between gyrina and all four of our other Physa populations, between pomilia and carolinae, and between pomilia and Charleston acuta, but not between pomilia and the acuta population from Philadelphia, nor between carolinae and either acuta population. These observations are consistent with the origin of hybrid sterility prior to hybrid inviability, and a hypothesis that speciation between pomilia and acuta may have been reinforced by selection for prezygotic reproductive isolation in sympatry. Conclusions We propose a two-factor model for the evolution of postzygotic reproductive incompatibility in this set of five Physa populations consistent with the Dobzhansky-Muller model of speciation, and a second two-factor model for the evolution of sexual incompatibility. Under these models, species trees may be said to correspond with gene trees in American populations of the freshwater snail, Physa. PMID:21615966

2011-01-01

73

Complete mitochondrial genome of the giant African snail, Achatina fulica (Mollusca: Achatinidae): a novel location of putative control regions (CR) in the mitogenome within Pulmonate species.  

PubMed

Abstract The whole sequence (15,057?bp) of the mitochondrial DNA (mtDNA) of the terrestrial snail Achatina fulica (order Stylommatophora) was determined. The mitogenome, as the typical metazoan mtDNA, contains 13 protein-coding genes (PCG), 2 ribosomal RNA genes (rRNA) and 22 transfer RNA genes (tRNA). The tRNA genes include two trnS without standard secondary structure. Interestingly, among the known mitogenomes of Pulmonata species, we firstly characterized an unassigned lengthy sequence (551?bp) between the cox1 and the trnV which may be the CR for the sake of its AT bases usage bias (65.70%) and potential hairpin structure. PMID:24975387

He, Zhang-Ping; Dai, Xia-Bin; Zhang, Shuai; Zhi, Ting-Ting; Lun, Zhao-Rong; Wu, Zhong-Dao; Yang, Ting-Bao

2014-06-30

74

Accumulation of microcystins in various organs of the freshwater snail Sinotaia histrica and three fishes in a temperate lake, the eutrophic Lake Suwa, Japan  

Microsoft Academic Search

So far, there has been only one study to examine microcystin (MC) contents in various organs of snails in a subtropical Chinese lake. In this study, tissue distribution and seasonal dynamics of MC-RR and -LR were investigated in various organs of a freshwater snail (Sinotaia histrica) in a temperate eutrophic lake, Lake Suwa, Japan. Accumulation of microcystins in some fish

Liqiang Xie; Atsushi Yokoyama; Koya Nakamura

2007-01-01

75

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

SciTech Connect

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.

Pyatt, F.B. [Nottingham Trent Univ. (United Kingdom). Dept. of Life Sciences; Pyatt, A.J. [Univ. of Bradford (United Kingdom). Dept. of Archaeological Sciences; Pentreath, V.W. [Univ. of Salford (United Kingdom). Dept. of Biological Sciences

1997-07-01

76

Molecular characterization of freshwater snails in the genus Bulinus: a role for barcodes?  

PubMed Central

Background Reliable and consistent methods are required for the identification and classification of freshwater snails belonging to the genus Bulinus (Gastropoda, Planorbidae) which act as intermediate hosts for schistosomes of both medical and veterinary importance. The current project worked towards two main objectives, the development of a cost effective, simple screening method for the routine identification of Bulinus isolates and the use of resultant sequencing data to produce a model of relationships within the group. Results Phylogenetic analysis of the DNA sequence for a large section (1009 bp) of the mitochondrial gene cytochrome oxidase subunit 1 (cox1) for isolates of Bulinus demonstrated superior resolution over that employing the second internal transcribed spacer (its2) of the ribosomal gene complex. Removal of transitional substitutions within cox1 because of saturation effects still allowed identification of snails at species group level. Within groups, some species could be identified with ease but there were regions where the high degree of molecular diversity meant that clear identification of species was problematic, this was particularly so within the B. africanus group. Conclusion The sequence diversity within cox1 is such that a barcoding approach may offer the best method for characterization of populations and species within the genus from different geographical locations. The study has confirmed the definition of some accepted species within the species groups but additionally has revealed some unrecognized isolates which underlines the need to use molecular markers in addition to more traditional methods of identification. A barcoding approach based on part of the cox1 gene as defined by the Folmer primers is proposed. PMID:18544153

Kane, Richard A; Stothard, J Russell; Emery, Aidan M; Rollinson, David

2008-01-01

77

The Structure of the Statocyst of the Freshwater Snail Biomphalaria Glabrata (Pulmonata, Basommatophora)  

NASA Technical Reports Server (NTRS)

The structure of the statocyst of the freshwater snail Biomphalaria glabrata has been examined by light and electron microscopy. The two statocysts are located on the dorsal-lateral side of the left and right pedal ganglion. The statocysts are spherical, fluid-filled capsules with a diameter of approximately 60 microns for young and 110 microns for adult snails. The wall of the cyst is composed of large receptor cells and many smaller supporting cells. The receptor cells bear cilia which are evenly distributed on the apical surface. The cilia have the typical 9+2 internal tubule configuration. Striate rootlets originate from the base of the basal body and run downward into the cytoplasm. Side-roots arise from one side of the basal body and a basal foot from the other. For each receptor cell, the basal foot always points to the periphery of the surface, indicating that the receptor cell is non-polarized. The receptor cells contain cytoplasmic organelles such as mitochondria, ribosomes, rough and smooth endoplasmic reticulum, compact Golgi bodies and multivesicular bodies. Supporting cells bearing microvilli are interposed between the receptor cells. The junction complex between the supporting cells and the receptor cells is composed of adherens and septate junctions, while between supporting cells only the adherens junctions are present. The static nerve arises from the lateral side of the cyst and contains axons in which parallel neurotubules and mitochondria are found. The axons arise directly from the base of the receptor cells without synapse. In the cyst lumen there are unattached statoconia. The statoconia have a plate-like or concentric membranous ring structure. Based on the morphology, the function of the statocyst in Biomphalaria is discussed.

Gao, Wenyuan; Wiederhold, Michael L.

1997-01-01

78

Resource limitation, competition and the influence of life history in a freshwater snail community  

Microsoft Academic Search

Previous work on a snail community occurring throughout lakes in southwestern Michigan showed that predation by molluscivorous sunfish had large impacts on only the rarest snail species. Thus, competition might play a major role in population limitation because dominant members of the snail community are relatively immune to predation. The present experiments were conducted to determine the extent to which

Craig W. Osenberg

1989-01-01

79

Neuro-Endocrine Control of Reproduction in Hermaphroditic Freshwater Snails: Mechanisms and Evolution  

PubMed Central

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

Koene, Joris M.

2010-01-01

80

Divergence preceding island formation among Aegean insular populations of the freshwater snail genus Pseudorientalia (Caenogastropoda: Truncatelloidea).  

PubMed

Freshwater snails that inhabit islands are excellent model organisms for testing relationships between geological events and phylogeography, especially in the Aegean region. Although many Aegean islands were searched in the present study, species of the genus Pseudorientalia were only found on Lesvos, Samos, and Chios. Phylogenetic relationships between specimens living on these three islands were analysed using COI and 16S rRNA molecular markers and morphological data. A high level of diversity was found between islands. Genetic distances between clades showed differences high enough for the samples from different islands to be considered distinct species (p-distance: 0.105-0.133). These results are also supported by obvious morphological differences in shell morphology between islands. The mean divergence time between the Lesvos clade and Samos/Chios clade was 24.13 ± 3.30 Mya; between the Samos and Chios clades the divergence time was 14.80 ± 1.11 Mya. Our data suggest that high divergence may have occurred between Pseudorientalia populations during the Upper and Middle Miocene, when the Aegean region was part of a united landmass. It is possible that the observed highly divergent Pseudorientalia clades are relicts of high regional diversity that existed in the past. PMID:25284387

Szarowska, Magdalena; Hofman, Sebastian; Osikowski, Artur; Falniowski, Andrzej

2014-10-01

81

Developmental toxicity, acute toxicity and mutagenicity testing in freshwater snails Biomphalaria glabrata (Mollusca: Gastropoda) exposed to chromium and water samples.  

PubMed

A protocol combining acute toxicity, developmental toxicity and mutagenicity analysis in freshwater snail Biomphalaria glabrata for application in ecotoxicological studies is described. For acute toxicity testing, LC50 and EC50 values were determined; dominant lethal mutations induction was the endpoint for mutagenicity analysis. Reference toxicant potassium dichromate (K2Cr2O7) was used to characterize B. glabrata sensitivity for toxicity and cyclophosphamide to mutagenicity testing purposes. Compared to other relevant freshwater species, B. glabrata showed high sensitivity: the lowest EC50 value was obtained with embryos at veliger stage (5.76mg/L). To assess the model applicability for environmental studies, influent and effluent water samples from a wastewater treatment plant were evaluated. Gastropod sensitivity was assessed in comparison to the standardized bioassay with Daphnia similis exposed to the same water samples. Sampling sites identified as toxic to daphnids were also detected by snails, showing a qualitatively similar sensitivity suggesting that B. glabrata is a suitable test species for freshwater monitoring. Holding procedures and protocols implemented for toxicity and developmental bioassays showed to be in compliance with international standards for intra-laboratory precision. Thereby, we are proposing this system for application in ecotoxicological studies. PMID:25259848

Tallarico, Lenita de Freitas; Borrely, Sueli Ivone; Hamada, Natália; Grazeffe, Vanessa Siqueira; Ohlweiler, Fernanda Pires; Okazaki, Kayo; Granatelli, Amanda Tosatte; Pereira, Ivana Wuo; Pereira, Carlos Alberto de Bragança; Nakano, Eliana

2014-12-01

82

A laboratory and in situ postexposure feeding assay with a freshwater snail.  

PubMed

Contaminant-driven feeding inhibition has direct and immediate consequences at higher levels of biological organization, by depressing the population consumption and thus hampering ecosystem functioning (e.g., grazing, organic matter decomposition). The present study aimed at developing a short-term laboratory and in situ assay based on the postexposure feeding of the freshwater snail Theodoxus fluviatilis. A method to precisely quantify feeding rates was first developed, consisting of a 3-h feeding period, in darkness, on 150 defrosted nauplii of the brine shrimp Artemia franciscana. Postexposure feeding after a 48-h exposure to cadmium was approximately as sensitive as survival, with the median effective concentration (EC50) and median lethal concentration (LC50) being 85?µg/L and 102?µg/L, respectively, and the 20% effective concentration (EC20) and 20% lethal concentration (LC20) being 41?µg/L and 77?µg/L, respectively. Together, both effects at the LC20 reduced population consumption by 56%. In situ experiments at reference sites covering broad ranges of current velocity, hardness, conductivity, sediment organic matter content, and sediment particle size distribution revealed the influence of these abiotic conditions on postexposure feeding, in the absence of contamination, to be negligible. The effectiveness of the in situ assay was evaluated at 5 sites contaminated with acid mine drainage. Surviving organisms at the single partially lethal site (37% mortality) presented a 54% feeding inhibition relative to the reference, whereas the population consumption would be inhibited by 71%, confirming the integration of survival and feeding to be pertinent for estimating contaminant effects at higher levels of biological organization. PMID:23733247

Correia, Vânia; Ribeiro, Rui; Moreira-Santos, Matilde

2013-09-01

83

Adaptive responses and latent costs of multigeneration cadmium exposure in parasite resistant and susceptible strains of a freshwater snail  

SciTech Connect

Population response to anthropogenic activities will be influenced by prior adaptation to environmental conditions. We tested how parasite-resistant and -susceptible strains of a freshwater snail responded to cadmium and elevated temperature challenges after having been exposed to low-level cadmium continuously for multiple generations. Snails exposed to cadmium for three generations were removed for the fourth generation, and challenged in the fifth generation with (1) chronic cadmium exposure over the entire life cycle, (2) acute cadmium exposure of adults, and (3) elevated temperature challenge of adults. The parasite susceptible NMRI strain is more cadmium tolerant than the parasite resistant BS90 strain and remained more tolerant than BS90 throughout this study. Additionally, NMRI exhibited greater adaptive capacity for cadmium than BS90 and became more tolerant of both chronic and acute cadmium challenges, while BS90 became more tolerant of acute cadmium challenge only. Fitness costs, reflected in population growth rate, were not apparent in fifth generation snails maintained in cadmium-free conditions. However, costs were latent and expressed as decreased tolerance to a secondarily imposed temperature stress. Adaptation to prior selection pressures can influence subsequent adaptation to anthropogenic stresses and may have associated costs that reduce fitness in novel environments.

Salice, Christopher J.; Anderson, Todd; Roesijadi, Guritno

2010-11-01

84

Control of feeding movements in the freshwater snail Planorbis corneus. I. Rhythmical neurons of buccal ganglia.  

PubMed

(1) The buccal mass of the freshwater snail Planorbis corneus, dissected together with the buccal ganglia, performs rhythmic feeding movements. Radula movements and the electrical activity in various nerves of buccal ganglia were recorded in such a preparation. The cycle of radula movements consisted of three phases: quiescence (Q), protraction (P) and retraction (R). The activity in the radular nerve was observed mainly in the P-phase and that in the dorsobuccal nerve, largely in the R-phase. (2) Isolated buccal ganglia were capable of generating a feeding rhythm, the activity in buccal nerves being similar to that observed in the buccal mass-buccal ganglion preparation, i.e., a burst in the radular nerve preceded a burst in the dorsobuccal nerve. The activity of neurons in isolated buccal ganglia during generation of the feeding rhythm has been studied with intracellular microelectrodes. About 10% of ganglion neurons exhibited periodic activity related to the feeding rhythm ("rhythmic" neurons). (3) Rhythmic neurons have been divided into 7 groups according to the phase of their activity and to the characteristics of slow oscillations of the membrane potential during the feeding cycle. Group 1 neurons revealed a gradual increase of depolarization during the Q- and P-phases. In subgroup 1e neurons, spike discharges began in the Q-phase, while in subgroup 1d neurons activity started in the P-phase. During the R-phase, group 1 neurons were strongly hyperpolarized, and their discharges terminated. In group 2 neurons, small depolarization gradually increased during the Q- and P-phases. Then, in the R-phase, a large (20-50 mV) rectangular wave of depolarization arose with superimposed high-frequency oscillations. Group 3 neurons exhibited an excitatory postsynaptic potential (EPSP) in the P-phase and inhibitory postsynaptic potential (IPSP) in the R-phase. The neurons of group 4 revealed two EPSPs: a small one in the P-phase and a larger one in the R-phase. Group 5 neurons exhibited an EPSP in the P-phase, those of group 7 - an IPSP in the R-phase, and those of group 9 - IPSPs in the P- and R-phases. Neurons within each of the groups 1, 2 and 4 were electrically coupled, and in addition, there were also electrical connections between neurons of groups 2 and 4. (4) Data are presented showing that neurons of groups 1 and 2 are the main source of postsynaptic potentials in rhythmic neurons in the P-phase and in the R-phase of the cycle, respectively. PMID:3384034

Arshavsky YuI; Deliagina, T G; Meizerov, E S; Orlovsky, G N; Panchin YuV

1988-01-01

85

The Effect of Aquatic Plant Abundance on Shell Crushing Resistance in a Freshwater Snail  

PubMed Central

Most of the shell material in snails is composed of calcium carbonate but the organic shell matrix determines the properties of calcium carbonate crystals. It has been shown that the deposition of calcium carbonate is affected by the ingestion of organic compounds. We hypothesize that organic compounds not synthesized by the snails are important for shell strength and must be obtained from the diet. We tested this idea indirectly by evaluating whether the abundance of the organic matter that snails eat is related to the strength of their shells. We measured shell crushing resistance in the snail Mexipyrgus churinceanus and the abundance of the most common aquatic macrophyte, the water lily Nymphaea ampla, in ten bodies of water in the valley of Cuatro Ciénegas, Mexico. We used stable isotopes to test the assumption that these snails feed on water lily organic matter. We also measured other factors that can affect crushing resistance, such as the density of crushing predators, snail density, water pH, and the concentration of calcium and phosphorus in the water. The isotope analysis suggested that snails assimilate water lily organic matter that is metabolized by sediment bacteria. The variable that best explained the variation in crushing resistance found among sites was the local abundance of water lilies. We propose that the local amount of water lily organic matter provides organic compounds important in shell biomineralization, thus determining crushing resistance. Hence, we propose that a third trophic level could be important in the coevolution of snail defensive traits and predatory structures. PMID:22970206

Chaves-Campos, Johel; Coghill, Lyndon M.; García de León, Francisco J.; Johnson, Steven G.

2012-01-01

86

Use of DGT and conventional methods to predict sediment metal bioavailability to a field inhabitant freshwater snail (Bellamya aeruginosa) from Chinese eutrophic lakes.  

PubMed

In this study, we used the diffusive gradients in thin films (DGT) and conventional methods (including SEM-AVS models, BCR sequential extraction and total metal concentrations) to assess sediment Cr, Ni, Cu, Zn, Cd and Pb bioavailability to field inhabitant freshwater snails (Bellamya aeruginosa) from Chinese eutrophic lakes. The performance of these methods and the relationship between DGT measurements and conventional methods were evaluated. The results showed that DGT-measured metal concentrations have weak correlations with results from tests using SEM-AVS models as well as sequentially extracted European Community Bureau of Reference (BCR) metal fractions. Among the methods used, Cr, Ni, Cu, and Pb measured by DGT were significantly correlated with metal concentrations in the tissue of snails, while SEM-AVS could predict Cr, Ni and Pb bioavailability well, but not SEM-AVS/fOC. Finally, BCR sequential extraction and total metal concentrations only correlated well with Pb bioavailability to snails. Overall, the results of this study indicated that DGT performed best in predicting metal accumulation in snails and which could be used to predict sediment metal bioavailability to field inhabitant snails from freshwater lake sediments due to their simple manipulation and validity. PMID:24295770

Yin, Hongbin; Cai, Yongjiu; Duan, Hongtao; Gao, Junfeng; Fan, Chengxin

2014-01-15

87

A new freshwater snail genus (Hydrobiidae, Gastropoda) from Montenegro, with a discussion on gastropod diversity and endemism in Skadar Lake  

PubMed Central

Abstract Karucia sublacustrina a new species of freshwater snails (Hydrobiidae, Gastropoda) is described based on material collected from Skadar Lake (Montenegro, Albania). The new species belongs to monotypic genus Karucia gen. n. The shell morphology and body shape of the new genus resembles Radomaniola Szarowska, 2006 and Grossuana Radoman, 1973, from which it differs in the larger shells with relatively slim and a slightly, but clearly shouldered body whorl. The number of gastropods from Skadar Lake basin tallies now 50 species. The adjusted rate of gastropod endemicity for Skadar Lake basin is estimated to be 38%. By compiling faunal and taxonomic data we also aim to provide information of relevance as to conservation efforts. PMID:23794834

Peši?, Vladimir; Glöer, Peter

2013-01-01

88

The value of the freshwater snail dip scoop sampling method in macroinvertebrates bioassessment of sugar mill wastewater pollution in Mbandjock, Cameroon.  

PubMed

Macroinvertebrates identification and enumeration may be used as a simple and affordable alternative to chemical analysis in water pollution monitoring. However, the ecological responses of various taxa to pollution are poorly known in resources-limited tropical countries. While freshwater macroinvertebrates have been used in the assessment of water quality in Europe and the Americas, investigations in Africa have mainly focused on snail hosts of human parasites. There is a need for sampling methods that can be used to assess both snails and other macroinvertebrates. The present study was designed to evaluate the usefulness of the freshwater snail dip scoop method in the study of macroinvertebrates for the assessment of the SOSUCAM sugar mill effluents pollution. Standard snail dip scoop samples were collected upstream and downstream of the factory effluent inputs, on the Mokona and Mengoala rivers. The analysis of the macroinvertebrate communities revealed the absence of Ephemeroptera and Trichoptera, and the thriving of Syrphidae in the sections of the rivers under high effluent load. The Shannon & Weaver diversity index was lower in these areas. The dip scoop sampling protocol was found to be a useful method for macroinvertebrates collection. Hence, this method is recommended as a simple, cost-effective and efficient tool for the bio-assessment of freshwater pollution in developing countries with limited research resources. PMID:18441407

Takougang, Innocent; Barbazan, Phillipe; Tchounwou, Paul B; Noumi, Emmanuel

2008-03-01

89

Gross mismatch between thermal tolerances and environmental temperatures in a tropical freshwater snail: climate warming and evolutionary implications.  

PubMed

The relationship between acute thermal tolerance and habitat temperature in ectotherm animals informs about their thermal adaptation and is used to assess thermal safety margins and sensitivity to climate warming. We studied this relationship in an equatorial freshwater snail (Clea nigricans), belonging to a predominantly marine gastropod lineage (Neogastropoda, Buccinidae). We found that tolerance of heating and cooling exceeded average daily maximum and minimum temperatures, by roughly 20°C in each case. Because habitat temperature is generally assumed to be the main selective factor acting on the fundamental thermal niche, the discordance between thermal tolerance and environmental temperature implies trait conservation following 'in situ' environmental change, or following novel colonisation of a thermally less-variable habitat. Whereas heat tolerance could relate to an historical association with the thermally variable and extreme marine intertidal fringe zone, cold tolerance could associate with either an ancestral life at higher latitudes, or represent adaptation to cooler, higher-altitudinal, tropical lotic systems. The broad upper thermal safety margin (difference between heat tolerance and maximum environmental temperature) observed in this snail is grossly incompatible with the very narrow safety margins typically found in most terrestrial tropical ectotherms (insects and lizards), and hence with the emerging prediction that tropical ectotherms, are especially vulnerable to environmental warming. A more comprehensive understanding of climatic vulnerability of animal ectotherms thus requires greater consideration of taxonomic diversity, ecological transition and evolutionary history. PMID:25526660

Polgar, Gianluca; Khang, Tsung Fei; Chua, Teddy; Marshall, David J

2015-01-01

90

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

PubMed

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

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

2014-06-01

91

OOCYTE DEGENERATION AND ALTERED OVIPOSITORY ACTIVITY INDUCED BY PARAQUAT IN THE FRESHWATER SNAIL PHYSA FONTINALIS (GASTROPODA: PULMONATA).  

PubMed

The freshwater snail Physa fontinalis was used as a bioindicator to study the effects of the herbicide Paraquat (PQ) in laboratory assays. The test solutions used, 0.125, 0.25, and 0.5 mg/l PQ, were in the range of the concentrations recommended for aquatic weed control. The study was carried out in two stages to determine the influence of PQ on the ovipository activity of Physa fontinalis, and the histological effects on these snails. Specimens exposed to PQ continued to be reproductively active, but the number of egg masses and eggs laid decreased significantly. Mortality was almost the same in all the experimental lots, but was significantly related to the production of egg masses only in the controls. The histological analysis showed a clear trend among PQ concentrations and degenerating oocytes, but no visible effects on the male sex-line were observed. By interfering with fertility, PQ has an action that may go well beyond its lethal effect on individuals, suggesting that this herbicide should be strictly regulated in weed control programmes. Moreover, since PQ was observed to interfere with the reproductive process, its endocrine disrupting action must not be excluded. PMID:12011245

Bacchetta, R.; Mantecca, P.; Vailati, G.

2002-05-01

92

Contrasting the distribution of phenotypic and molecular variation in the freshwater snail Biomphalaria pfeifferi, the intermediate host of Schistosoma mansoni  

PubMed Central

Population differentiation was investigated by confronting phenotypic and molecular variation in the highly selfing freshwater snail Biomphalaria pfeifferi, the intermediate host of Schistosoma mansoni. We sampled seven natural populations separated by a few kilometers, and characterized by different habitat regimes (permanent/temporary) and openness (open/closed). A genetic analysis based on five microsatellite markers confirms that B. pfeifferi is a selfer (s?0.9) and exhibits limited variation within populations. Most pairwise FST were significant indicating marked population structure, though no isolation by distance was detected. Families from the seven populations were monitored under laboratory conditions over two generations (G1 and G2), allowing to record several life-history traits, including growth, fecundity and survival, over 25 weeks. Marked differences were detected among populations for traits expressed early in the life cycle (up to sexual maturity). Age and size at first reproduction had high heritability values, but such a trend was not found for early reproductive traits. In most populations, G1 snails matured later and at a larger size than G2 individuals. Individuals from permanent habitats matured at a smaller size and were more fecund than those from temporary habitats. The mean phenotypic differentiation over all populations (QST) was lower than the mean genetic differentiation (FST), suggesting stabilizing selection. However, no difference was detected between QST and FST for both habitat regime and habitat openness. PMID:23321708

Tian-Bi, Y-NT; Jarne, P; Konan, J-NK; Utzinger, J; N'Goran, E K

2013-01-01

93

Effects of 17?-methyltestosterone on the reproduction of the freshwater snail Biomphalaria glabrata.  

PubMed

17-?-methyltestosterone (MT) is a synthetic hormone used in fish hatcheries to induce male monosex. Snails hold promise as possible test models to assess chemicals acting on the endocrine system. Biomphalaria glabrata is an aquatic gastropod mollusk (Pulmonata, Planorbidae) that can be easily maintained in aquaria, predisposing the species for use in ecotoxicological testing. This study evaluated the reproductive effects of MT on B. glabrata by examining histological changes and its reproductive performance. Ten snails per group were exposed for 4 weeks to different concentrations of MT (0.01, 0.1, and 1.0 mg/L). The total number of laid eggs, egg mass per group, size of type V oocytes, and production of spermatozoids were determined. Reproduction of B. glabrata was affected by MT. At the lowest concentration (0.01 mg/L), MT caused a statistically significant increase in the number of egg mass per snail compared with controls unexposed to MT. Histopathology analyses showed an increase in the sperm production at the higher MT concentrations of 0.1 and 1.0 mg/L. Chromatographic analyses of water samples showed that MT concentrations rapidly declined within a 96-h period. These results highlight the importance of giving more support to regulatory authorities, since MT is not registered for use on fish hatcheries in many countries around the world. Wastewater from fish farms discharged into aquatic ecosystems should be monitored for MT residues, since its presence could compromise the reproduction of other native snail species. PMID:24615026

Rivero-Wendt, C L G; Borges, A C; Oliveira-Filho, E C; Miranda-Vilela, A L; Ferreira, M F N; Grisolia, C K

2014-01-01

94

Trait compensation and cospecialization in a freshwater snail: size, shape and antipredator behaviour  

Microsoft Academic Search

We examined relationships between individual differences in antipredator behaviour and prey morphological characters (size, shape) that influence prey vulnerability. Behavioural responses of Physa gyrina to chemical cues associated with predation by crayfish Orconectes rusticus, were assayed in the laboratory for 6 days over a 13-day period. Snails displayed consistent, individually repeatable responses to the predation cues, including hiding (refuge use)

Thomas J. Dewitt; Andrew Sih; Jeffrey A. Hucko

1999-01-01

95

EFFECTS OF COPPER, NICKEL AND ZINC ON THREE SPECIES OF OREGON FRESHWATER SNAILS  

EPA Science Inventory

Three snail species collected from western Oregon were exposed to metals - Juga plicifera and Lithoglyphus virens, which inhabit cool coastal streams, and Physa gyrina, which is found in Willamette Valley ponds. J. plicifera were exposed in flow-through laboratory tests to copper...

96

An experimental heat wave changes immune defense and life history traits in a freshwater snail  

PubMed Central

The predicted increase in frequency and severity of heat waves due to climate change is expected to alter disease dynamics by reducing hosts' ability to resist infections. This could take place via two different mechanisms: (1) through general reduction in hosts' performance under harsh environmental conditions and/or (2) through altered resource allocation that reduces expression of defense traits in order to maintain other traits. We tested these alternative hypotheses by measuring the effect of an experimental heat wave (25 vs. 15°C) on the constitutive level of immune defense (hemocyte concentration, phenoloxidase [PO]-like activity, antibacterial activity of hemolymph), and life history traits (growth and number of oviposited eggs) of the great pond snail Lymnaea stagnalis. We also manipulated the exposure time to high temperature (1, 3, 5, 7, 9, or 11 days). We found that if the exposure to high temperature lasted <1 week, immune function was not affected. However, when the exposure lasted longer than that, the level of snails' immune function (hemocyte concentration and PO-like activity) was reduced. Snails' growth and reproduction increased within the first week of exposure to high temperature. However, longer exposures did not lead to a further increase in cumulative reproductive output. Our results show that short experimental heat waves do not alter immune function but lead to plastic responses that increase snails' growth and reproduction. Thus, although the relative expression of traits changes, short experimental heat waves do not impair snails' defenses. Negative effects on performance get pronounced when the heat waves are prolonged suggesting that high performance cannot be maintained over long time periods. This ultimately reduces the levels of defense traits. PMID:24455121

Leicht, Katja; Jokela, Jukka; Seppälä, Otto

2013-01-01

97

Apple Snails (Ampullariidae)  

NSDL National Science Digital Library

This web site provides information on apple snails (family Ampullariidae), the largest living freshwater snails on earth, often kept as aquarium pets because of their attractive appearance and size. Topics include the care of apple snails, their anatomy, species and genera, and information on snail pests, embryology, and genetics. There is also a frequently-asked-questions feature, photos, links to web sites and literature, and an online discussion forum.

Stijn A. I. Ghesquiere

98

Identification of trematode cercariae carrying Neorickettsia risticii in freshwater stream snails.  

PubMed

We provide evidence of Neorickettsia (Ehrlichia) risticii Holland, the agent of Potomac horse fever, in trematode larval stages found in aquatic snails and insects collected from a stream in Korea, using nested polymerase chain reaction (PCR) and sequence analysis of the 16S rRNA gene fragment amplified from several cercaria species. It was observed that of 423 (13.1%) of 3,219 snails infected with cercariae, 77 (20.8% of the 371) were infected with N. risticii. Five families of trematode cercariae, Schistosomatidae, Echimostomatidae, Heterophyidae, Microphallidae, and Acanthocopidae were identified morphologically within Semisulcospira libertina, Radix auricularia coreana, and S. gottschei snails. Echinostoma cinetorchis, E. hortense, and Metagonimus sp. were identified based on both the cercarial morphology as well as by phylogenetic analysis of the amplified 18S rRNA gene sequences. Adult aquatic insects were also collected from the same sites and were sorted into five species, Ischnura asiatica in Coenagrionidae and Calopteryx japonica, Sympetrum darwinianum, Symptrum eroticum, and Symptrum parvulum in Calopterygoidae. One thousand and two hundred eighty five metacercariae (classified into groups A through F) were isolated from 310 adult aquatic insects, and the average number of metacercariae per aquatic insect was 4.1. However, there was no amplification of N. risticii from these metacercariae. PMID:12860634

Park, Bae-Keun; Kim, Meen-Ju; Kim, Eun-Ha; Kim, Min-Seok; Na, Dong-Gyun; Chae, Joon-Seok

2003-06-01

99

Operculum closing as a defence against predatory leeches in four British freshwater prosobranch snails  

Microsoft Academic Search

The defence reaction of operculum closing in response to the presence of the molluscivorous leech Glossiphonia complanata (L.) and the non-molluscivorous Erpobdella octoculata (L.) was studied in four species of freshwater prosobranch gastropod. Bithynia tentaculata (L.) and Valvata piscinalis (Mller) can distinguish between the leeches, reacting only to G. complanata. V. piscinalis is capable of a greater degree of distance

Paul M. Kelly; Jenny S. Cory

1987-01-01

100

Toxic effect of two common Euphorbiales latices on the freshwater snail Lymnaea acuminata.  

PubMed

The aqueous and serially purified latex extracts of plants Euphorbia pulcherima and Euphorbia hirta (family Euphorbiaceae) have potent molluscicidal activity. Sub-lethal doses (40 and 80% of LC(50)) of aqueous and partially purified latex extracts of both the plants also significantly alter the levels of total protein, total free amino acid, nucleic acid (DNA and RNA) and the activity of enzyme protease and acid and alkaline phosphatase in nervous tissue of the snail Lymnaea acuminata in time and dose dependent manner. E. pulcherima and E. hirta are common medicinal plants of family Euphorbiaceae. E. pulcherima is useful for a variety of conditions, such as rheumatism, snakebite, asthma, obstipation, and skin-diseases. While, E. hirta is also used in cough, asthma, colic, dysentery, and genito urinary diseases. PMID:21782684

Singh, Sunil Kumar; Yadav, R P; Singh, Digvijay; Singh, Ajay

2004-01-01

101

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

PubMed Central

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

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

2014-01-01

102

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

PubMed

Repeated pesticide contaminations of lentic freshwater systems located within agricultural landscapes may affect population evolution in non-target organisms, especially in species with a fully aquatic life cycle and low dispersal ability. The issue of evolutionary impact of pollutants is therefore conceptually important for ecotoxicologists. The impact of historical exposure to pesticides on genetic divergence was investigated in the freshwater gastropod Lymnaea stagnalis, using a set of 14 populations from contrasted environments in terms of pesticide and other anthropogenic pressures. The hypothesis of population adaptive divergence was tested on 11 life-history traits, using Q(ST)-F(ST) comparisons. Despite strong neutral differentiation (mean F(ST) = 0.291), five adult traits or parameters were found to be under divergent selection. Conversely, two early expressed traits showed a pattern consistent with uniform selection or trait canalization, and four adult traits appeared to evolve neutrally. Divergent selection patterns were mostly consistent with a habitat effect, opposing pond to ditch and channel populations. Comparatively, pesticide and other human pressures had little correspondence with evolutionary patterns, despite hatching rate impairment associated with global anthropogenic pressure. Globally, analyses revealed high genetic variation both at neutral markers and fitness-related traits in a species used as model in ecotoxicology, providing empirical support for the need to account for genetic and evolutionary components of population response in ecological risk assessment. PMID:25207985

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

2014-01-01

103

Sole smooth muscle states determine gliding rate in the freshwater snail Lymnaea stagnalis.  

PubMed

The sole of crawling gastropods is a unique model for studying the function of smooth muscles and ciliated epithelium. The gastropod snail Lymnaea stagnalis glides over the substratum without visible muscular contraction in its sole; consequently, the gliding was thought to be due to sole cilia. However, we have shown that the sole muscles in Lymnaea are phasic smooth muscles. They contribute extensively to gliding rate, which is directly correlated with the sole length (longitudinal sole muscle tonus) that varies widely during gliding. Here, we show that the linear relationship between gliding rate and sole length in Lymnaea may be modified. Serotonin increases gliding rate and has no effect on sole length. Dopamine contracts the sole and, consequently, slows the gliding rate, while ergometrine (a blocker of dopamine receptors) relaxes the sole and increases gliding rate. These influences on locomotion rate and sole length are similar to those obtained earlier for Helix lucorum, in which the substances changed the number and contraction force of muscle cells involved in peristaltic locomotory waves. Taken together, the data obtained here for Lymnaea and earlier for Helix describe the fundamental mechanisms for controlling phasic smooth muscles. PMID:24445444

Pavlova, Galina A

2013-12-01

104

The effects of engineered nanoparticles on survival, reproduction, and behaviour of freshwater snail, Physa acuta (Draparnaud, 1805).  

PubMed

Increasing uses of engineered nanoparticles (ENPs) in commercial products and industrial applications has eventually resulted to their releases into atmospheric, terrestrial, and aquatic environments. However, knowledge gaps in ENPs toxicity, fate, and behaviour currently limit our ability to quantify risk assessment of materials with nanoscale dimensions, and therefore, the extent of the resultant environmental impacts remains unknown. In the present study, we evaluated the effects of ?-alumina, ?-alumina, modified TiO(2) (M-TiO(2)), and commercial TiO(2) (C-TiO(2)) ENPs on the survival, behaviour, and early life stages of the freshwater snail Physa acuta (Draparnaud). The toxicity evaluation was carried out after spiking commercial sand with ENPs concentrations of 0.005, 0.05, or 0.5 gk g(-1). Our findings suggest that increases of ?-alumina and ?-alumina concentrations at sub-lethal level concentrations caused significant reduction in the embryo growth rate and embryo hatchability. In addition, these ENPs induced observable developmental deformities of the embryos. In addition, toxicity evaluations using acute 96-h and chronic 28-d tests showed exposure duration may be a significant factor in ENPs-induced toxicity. Therefore, long-term exposure of aquatic organisms to ENPs - potentially can alter certain ecological populations at different trophic levels - and may compromise the entire aquatic ecological functionality. The percentage hatchlings in test chambers containing 0.5 gk g(-1) ?-alumina and ?-alumina concentration was 50% less to those observed in the controls. Our results suggest the embryonic growth and hatchability tests are useful endpoints in chronic sediment toxicity tests for determining the toxic thresholds of ENPs in sediment environment. Although no snail mortalities were observed during the static 96-h test containing sediment spiked with different concentrations of M-TiO(2), C-TiO(2), ?-alumina and ?-alumina - the antioxidant enzymatic assay results indicated a significant change in antioxidant levels which altered peroxidation at 0.05 or 0.5 gk g(-1)concentrations for both ?-alumina and ?-alumina. PMID:20943245

Musee, N; Oberholster, P J; Sikhwivhilu, L; Botha, A-M

2010-11-01

105

Development and evaluation of loop-mediated isothermal amplification (LAMP) for rapid detection of Clonorchis sinensis from its first intermediate hosts, freshwater snails.  

PubMed

Clonorchiasis, caused by Clonorchis sinensis, is a key foodborne zoonosis, which is mainly found in China, Korea and Vietnam. Detection of this parasite from the second intermediate host, the freshwater fish is the common method for epidemiological surveys of this parasite, but is time consuming, labour intensive and easily leads to misdiagnosis. In this study, we have developed a rapid, sensitive and reliable molecular method for the diagnosis of C. sinensis from its first intermediate hosts, freshwater snails, based on a loop-mediated isothermal amplification (LAMP) method. The specific amplified fragment from genomic DNA of C. sinensis did not cross-react with those from other relevant trematodes and a range of hosts (freshwater fish, shrimps and snails) of C. sinensis living in similar environments. The detection limit of the LAMP method was as low as 10 fg which was 1000 times more sensitive than conventional PCR, which was also demonstrated by successful application to field samples. These results show that the LAMP method is a more sensitive tool than conventional PCR for the detection of C. sinensis infection in the first intermediate hosts and, due to a simpler protocol, is an ideal molecular method for field-based epidemiological surveys of this parasite. PMID:23870065

Chen, Y; Wen, T; Lai, D-H; Wen, Y-Z; Wu, Z-D; Yang, T-B; Yu, X-B; Hide, G; Lun, Z-R

2013-09-01

106

[Distribution Of Medically Important Freshwater Snails And Larval Trematodes From Parafossarulus Manchouricus And Semisulcospira Libertina Around The Jinyang Lake In Kyongsang-Nam-Do, Korea  

PubMed

The Jinyang Lake is dammed up Nam River, and surrounded by Jinju city and four counties; Jinyang, Sanchong, Hadong, and Sachon in Kyongsang-Nam-Do, Korea. The area around this man-made lake have been known as an endemic focus of clonorchiasis in Korea. The present study was first aimed to know the distribution of freshwater mollusks including medically important snails, and larval trematodes shed from Parafossarulus manchouricus and Semisulcospira libertina. In addtion to above studies, water analyses in each snail habitat were carried out in order to figure out a part of their environmental factors. This malaco-ecological survey was done at the six areas around upper, middle and lower parts of the lake for 4 months, August-November, 1983. Total nine species of freshwater mollusks were collected throughout the study: 4 species of gastropods; Semisulcospira libertina, Cipangopaludina chinensis, Parafossarulus manchouricus and Radix auricularia, and 5 species of bivalves; Unio douglasiae, Anodonta woodiana, Lamprotula gottschei, Corbicula fluminea and Limnoperma lucustris. Out of nine species of freshwater mollusks, three species of gastropods; S. libertina, P. manchouricus and R. auricularia were medically important in terms of the transmission of digenetic trematodes to humans. P. manchouricus and R. auricularia were mainly collected from the shallow ponds and the irrigation channels with the muddy basin, but S. libertina and the bivalves were only collected from the stream of Nam river where the gravels and rocks were dominant. The levels of dissolved oxygen(D.O.) and biochemical oxygen demand (B.O.D.(5)) of the water specimens sampled from the study areas ranged from 6.0 to 9.6 ppm and from 0.4 to 1.6 ppm respectively. As a result, it is considered that water system around the Jinyang Lake might be relatively clean without any heavy pollution of aquatic microorganisms and organic materials during the period of this study. On the other hand, eight metalic constituents from the water samples were also assayed, and all metalic ions detected were remarkably low below the legal criteria. However, calcium ion in the water samples from the habitats of P. manchouricus was considerably higher than others. Infection rates of digenetic trematodes in the snails were 6.9 % in P. manchouricus and 4.8 poercent in S. libertina, respectively. P. manchouricus snails harboring with the cercariae of Clonorchis sinensis were only 0.14 % among the snails examined and other trematode cercariae except cercaria of C. sinensis were; furcocercus cercariae, cercaria of Loxogenes liberum type I and II. S. libertina snails parasitized with the cercariae of Metagonimus yokogawai were 1.5 % out of the snails examined and no cercaria of Paragonimus westermani was found in S. libertina snails in the present study. Digenetic trematode cercariae other then M. yokogawai in S. libertina snails were: Cercaria yoshidae (B type), Cercaria cristata, Cercaria innominatum, Cercaria of Centrocestus formosanus and Cercaria nipponensis. PMID:12902649

Cho, Hae Chang; Chung, Pyung Rim; Lee, Keun Tae

1983-12-01

107

Asymmetric reproductive isolation during simultaneous reciprocal mating in pulmonates.  

PubMed

The generality of asymmetric reproductive isolation between reciprocal crosses suggests that the evolution of isolation mechanisms often proceeds in reciprocal asymmetry. In hermaphroditic snails that copulate simultaneously and reciprocally, asymmetry in premating isolation may not be readily detectable because the failure of the symmetric performance of courtship would prevent copulation from occurring. On the other hand, through their prolonged copulation, snails discriminate among mates when exchanging spermatophores for their benefit and thus may exhibit asymmetric reproductive isolation during interspecific mating. However, no clear case of reciprocal asymmetry has been found in reproductive isolation between snail species. Here we show a discrete difference in hybridization success between simultaneous reciprocal copulations between two species of pulmonate snails. Premating isolation of Bradybaena pellucida (BP) and Bradybaena similaris (BS) is incomplete in captivity. In interspecific copulation, BP removes its penis without transferring a spermatophore, while BS sires hybrids by inseminating BP. Thus, 'male' BP or 'female' BS rejects the other individual, while female BP and male BS accept each other, so that the two sexes of either BP or BS oppose each other in mate discrimination. Our results are a clear example of asymmetry in reproductive isolation during simultaneous reciprocal mating between hermaphroditic animals. PMID:19141413

Wiwegweaw, Amporn; Seki, Keiichi; Mori, Hiroshi; Asami, Takahiro

2009-04-23

108

Asymmetric reproductive isolation during simultaneous reciprocal mating in pulmonates  

PubMed Central

The generality of asymmetric reproductive isolation between reciprocal crosses suggests that the evolution of isolation mechanisms often proceeds in reciprocal asymmetry. In hermaphroditic snails that copulate simultaneously and reciprocally, asymmetry in premating isolation may not be readily detectable because the failure of the symmetric performance of courtship would prevent copulation from occurring. On the other hand, through their prolonged copulation, snails discriminate among mates when exchanging spermatophores for their benefit and thus may exhibit asymmetric reproductive isolation during interspecific mating. However, no clear case of reciprocal asymmetry has been found in reproductive isolation between snail species. Here we show a discrete difference in hybridization success between simultaneous reciprocal copulations between two species of pulmonate snails. Premating isolation of Bradybaena pellucida (BP) and Bradybaena similaris (BS) is incomplete in captivity. In interspecific copulation, BP removes its penis without transferring a spermatophore, while BS sires hybrids by inseminating BP. Thus, ‘male’ BP or ‘female’ BS rejects the other individual, while female BP and male BS accept each other, so that the two sexes of either BP or BS oppose each other in mate discrimination. Our results are a clear example of asymmetry in reproductive isolation during simultaneous reciprocal mating between hermaphroditic animals. PMID:19141413

Wiwegweaw, Amporn; Seki, Keiichi; Mori, Hiroshi; Asami, Takahiro

2009-01-01

109

Isotopic niche metrics as indicators of toxic stress in two freshwater snails.  

PubMed

Descriptors of trophic niche and of food web structure and function have been suggested as integrative and sensitive endpoints of toxicant effects. In the present study, carbon and nitrogen stable isotope signatures were used to assess the effects of the dithiocarbamate fungicide thiram (35 and 170?g/L nominal concentrations) and of a petroleum distillate (0.01, 0.4, 2 and 20mg/L nominal loadings as Hydrocarbon Emulsion or Hydrocarbon Water Accommodated Fraction) on the trophic niche of two freshwater gastropods in artificial streams (Radix peregra) and ponds (Lymnaea stagnalis). Results were analyzed using classical univariate statistical methods and recently proposed uni- and multivariate metrics of the realized trophic niche of species. The trophic niche metrics were highly sensitive to both types of chemicals, but exposure resulted in different response patterns according to the nature of the tested compound. Thiram clearly affected gastropod trophic niche leading to a change in the food resources used and resulting in trophic niche expansion (i.e., increase of diversity of used resources, especially dead animals) or trophic niche contraction (i.e., decrease of diversity of used resources) across time. Both gastropod taxa exposed to hydrocarbons showed a clear trophic niche expansion. Trophic niche metrics therefore provide a promising way of investigating non-lethal effects of exposure to organic chemicals on aquatic invertebrates, and subsequent disturbances in food webs. PMID:24691210

Bayona, Yannick; Roucaute, Marc; Cailleaud, Kevin; Lagadic, Laurent; Bassères, Anne; Caquet, Thierry

2014-06-15

110

Comparative analysis of circulating hemocytes of the freshwater snail Pomacea canaliculata.  

PubMed

Molluscs are invertebrates of great relevance for economy, environment and public health. The numerous studies on molluscan immunity and physiology registered an impressive variability of circulating hemocytes. This study is focused on the first characterization of the circulating hemocytes of the freshwater gastropod Pomacea canaliculata, a model for several eco-toxicological and parasitological researches. Flow cytometry analysis identified two populations of hemocytes on the basis of differences in size and internal organization. The first population contains small and agranular cells. The second one displays major size and a more articulated internal organization. Light microscopy evidenced two principal morphologies, categorized as Group I (small) and II (large) hemocytes. Group I hemocytes present the characteristics of blast-like cells, with an agranular and basophilic cytoplasm. Group I hemocytes can adhere onto a glass surface but seem unable to phagocytize heat-inactivated Escherichia coli. The majority of Group II hemocytes displays an agranular cytoplasm, while a minority presents numerous granules. Agranular cytoplasm may be basophilic or acidophilic. Granules are positive to neutral red staining and therefore acidic. Independently from their morphology, Group II hemocytes are able to adhere and to engulf heat-inactivated E. coli. Transmission electron microscopy analysis clearly distinguished between agranular and granular hemocytes and highlighted the electron dense content of the granules. After hemolymph collection, time-course analysis indicated that the Group II hemocytes are subjected to an evident dynamism with changes in the percentage of agranular and granular hemocytes. The ability of circulating hemocytes to quickly modify their morphology and stainability suggests that P. canaliculata is endowed with highly dynamic hemocyte populations able to cope with rapid environmental changes as well as fast growing pathogens. PMID:23422816

Accorsi, Alice; Bucci, Laura; de Eguileor, Magda; Ottaviani, Enzo; Malagoli, Davide

2013-05-01

111

Freshwater Ecosystems  

NSDL National Science Digital Library

In this activity, learners create a freshwater ecosystem in a large plastic bottle. Learners cut and prepare bottles, then fill with water, aquatic plants, snails and fish. Learners observe their mini-ecosystem over time to see what changes--such as the color of the water, the water temperature, plant growth, and behavior and/or population of the snails or fish. The activity serves as a model for larger freshwater ecosystems such as ponds, lakes, rivers, streams, wetlands, reservoirs and groundwater.

2013-12-18

112

Species diversity of Plagiorchis Lühe, 1899 (Digenea: Plagiorchiidae) in lymnaeid snails from freshwater ecosystems in central Europe revealed by molecules and morphology.  

PubMed

Larval stages of Plagiorchis spp. are both ubiquitous and ecologically important parasites in snail populations of freshwater ecosystems in Europe. However, difficulties in distinguishing the morphologically similar cercariae used for species identification, may lead to underestimation of species diversity. In this study, 38 isolates of Plagiorchis spp. infecting two lymnaeid snails, Lymnaea stagnalis (L.) and Radix auricularia (L.), in five central European freshwater ecosystems were subjected to morphological and molecular assessment. Five morphologically homogeneous and genetically distinct lineages of Plagiorchis spp. were identified via matching molecular data for the mitochondrial cytochrome c oxidase subunit I (cox1) gene with detailed morphological and morphometric data of the cercariae. Comparative sequence analysis using partial 28S rDNA and ITS1-5.8S-ITS2 sequences revealed that three distinct cox1 lineages are conspecific with Plagiorchis elegans (Rudolphi, 1802), P. maculosus (Rudolphi, 1802) and P. koreanus Ogata, 1938, respectively, whereas the lineage identified based on cercarial morphology as P. neomidis Brendow, 1970 plus a single isolate that could not be assigned to a described species, did not match any of the available sequences for Plagiorchis spp. A key to the cercariae of Plagiorchis spp. parasitising lymnaeid populations in central Europe is provided to facilitate identification. PMID:24711111

Zikmundová, Jana; Georgieva, Simona; Faltýnková, Anna; Soldánová, Miroslava; Kostadinova, Aneta

2014-05-01

113

Advances in the Genomics and Proteomics of the Freshwater Intermediate Snail Host of Schistosoma mansoni, Biomphalaria glabrata  

Microsoft Academic Search

\\u000a Molecular events governing the interplay between the intermediate snail host, Biomphalaria glabrata, and its parasitic trematodes are gradually being unraveled. The last 20 years has seen an upsurge in the number of gene\\u000a sequences and proteins that are expressed, differentially regulated, and diversified in this snail in relation to its role\\u000a as an obligate host for an important human pathogen,

Wannaporn Ittiprasert; Jocelyn Myers; Edwin C. Odoemelam; Nithya Raghavan; Fred Lewis; Joanna M. Bridger; Matty Knight

114

First evidence of "paralytic shellfish toxins" and cylindrospermopsin in a Mexican freshwater system, Lago Catemaco, and apparent bioaccumulation of the toxins in "tegogolo" snails (Pomacea patula catemacensis).  

PubMed

Exposure to cyanobacterial toxins in freshwater systems, including both direct (e.g., drinking water) and indirect (e.g., bioaccumulation in food webs) routes, is emerging as a potentially significant threat to human health. We investigated cyanobacterial toxins, specifically cylindrospermopsin (CYN), the microcystins (MCYST) and the "paralytic shellfish toxins" (PST), in Lago Catemaco (Veracruz, Mexico). Lago Catemaco is a tropical lake dominated by Cylindrospermopsis, specifically identified as Cylindrospermopsis catemaco and Cylindrospermopsis philippinensis, and characterized by an abundant, endemic species of snail (Pomacea patula catemacensis), known as "tegogolos," that is both consumed locally and commercially important. Samples of water, including dissolved and particulate fractions, as well as extracts of tegogolos, were screened using highly specific and sensitive ELISA. ELISA identified CYN and PST at low concentrations in only one sample of seston; however, both toxins were detected at appreciable quantities in tegogolos. Calculated bioaccumulation factors (BAF) support bioaccumulation of both toxins in tegogolos. The presence of CYN in the phytoplankton was further confirmed by HPLC-UV and LC-MS, following concentration and extraction of algal cells, but the toxin could not be confirmed by these methods in tegogolos. These data represent the first published evidence for CYN and the PST in Lago Catemaco and, indeed, for any freshwater system in Mexico. Identification of the apparent bioaccumulation of these toxins in tegogolos may suggest the need to further our understanding of the transfer of cyanobacterial toxins in freshwater food webs as it relates to human health. PMID:19651152

Berry, John P; Lind, Owen

2010-05-01

115

Detection and quantification of schistosome DNA in freshwater snails using either fluorescent probes in real-time PCR or oligochromatographic dipstick assays targeting the ribosomal intergenic spacer.  

PubMed

Several DNA probes were designed for use in real-time polymerase chain reaction (PCR) assays to target sequence variation within the ribosomal intergenic spacer (IGS) of schistosomes. A sub-section of the IGS (?300bp) was amplified, with cross-specific primers, after which group-specific fluorescent, locked nucleic acid probes were assessed for their ability to differentiate and quantify DNA from Schistosoma haematobium and Schistosoma mansoni group parasites. A number of fluorescent probe candidates were screened and validated against genomic DNA from adult schistosome worms and laboratory infected freshwater snails. Two fluorescent, locked nucleic acid probes ShaemLNA5 and SmanLNA2, of 20-26bp in length, were identified and found to be effective in providing evidence of infection in field-collected snails. To adapt these real-time PCR assays for more resource-poor laboratory settings, a PCR-restriction fragment length polymorphism (RFLP) assay was developed and primer/probe combinations were modified for use in oligochromatography, a DNA 'dipstick' technology. An appropriate dipstick was developed, inclusive of internal amplification and amplicon migration controls that could be of particular importance for assessing schistosome transmission dynamics. These assays and tools also have future potential for use in detection of schistosome infections in humans and livestock. PMID:22100540

Kane, Richard A; Stothard, J Russell; Rollinson, David; Leclipteux, Thierry; Evraerts, Jonathan; Standley, Claire J; Allan, Fiona; Betson, Martha; Kaba, Rehana; Mertens, Pascal; Laurent, Thierry

2013-11-01

116

The Effects of Incubation Temperature on Development Time and Juvenile Size in the Freshwater Snail Physa sp  

Microsoft Academic Search

In 2002 we discovered that eggs of the snail Physa sp., when incubated at 20°C, produced larger juveniles than eggs incubated at 25°C. This study is a continuation of this earlier effort. Physa sp. eggs are laid in masses, with many egg capsules surrounded by a gelatinous material. Collected masses were each divided into four equal parts. Two sections were

Pierce Jennifer

2003-01-01

117

Freshwater snails (Mollusca: Gastropoda) from the Commonwealth of Dominica with a discussion of their roles in the transmission of parasites  

E-print Network

and H. trivolvis are established on Dominica, West Indies. We tested a limited number of M. tuberculata Indies The Commonwealth of Dominica is a small (790 km2 ) mountainous island nation in the West Indies and veterinary health significance of these snails. Key words: Biomphalaria, Gundlachia, Helisoma, Physa, West

Dillon, Robert T.

118

INTRODUCTION Predator avoidance in aquatic snails is facilitated by surfacing and  

E-print Network

shell-crushing sunfish or crayfish (Alexander and Covich, 1991; Brown, 1991). Additionally, and central to the intensity of the predatory attack (Arshavsky et al., 1994). Pulmonate snails, such as the common pond snail more vulnerable to benthic predators such as crayfish during that time. A, presumably, sub

Grosell, Martin

119

A snail perspective on the biogeography of Sulawesi, Indonesia: origin and intra-island dispersal of the viviparous freshwater gastropod Tylomelania.  

PubMed

The complex geological history of the Indonesian island Sulawesi has shaped the origin and subsequent diversification of its taxa. For the endemic freshwater snail Tylomelania a vicariant origin from the Australian margin has been hypothesized. Divergence time estimates from a mtDNA phylogeny based on a comprehensive island-wide sampling of Tylomelania fit regional tectonic constraints and support the 'out-of-Australia' vicariance hypothesis. The Banggai-Sula region of the Sula Spur, the Australian promontory colliding with West Sulawesi during the Miocene, is identified as a possible source area for the colonization of Sulawesi by the ancestor of Tylomelania. The molecular phylogeny also shows a rapid diversification of Tylomelania into eight major lineages with very little overlap in their distribution on the island. Haplotype networks provide further evidence for a strong spatial structure of genetic diversity in Tylomelania. Distribution boundaries of the major lineages do at best partially coincide with previously identified contact zones for other endemic species groups on Sulawesi. This pattern has likely been influenced by the poor dispersal capabilities and altitudinal distribution limits of this strict freshwater inhabitant. We suggest that late Miocene and Pliocene orogeny in large parts of Sulawesi has been the vicariant event driving primary diversification in Tylomelania. PMID:24971564

von Rintelen, Thomas; Stelbrink, Björn; Marwoto, Ristiyanti M; Glaubrecht, Matthias

2014-01-01

120

A Snail Perspective on the Biogeography of Sulawesi, Indonesia: Origin and Intra-Island Dispersal of the Viviparous Freshwater Gastropod Tylomelania  

PubMed Central

The complex geological history of the Indonesian island Sulawesi has shaped the origin and subsequent diversification of its taxa. For the endemic freshwater snail Tylomelania a vicariant origin from the Australian margin has been hypothesized. Divergence time estimates from a mtDNA phylogeny based on a comprehensive island-wide sampling of Tylomelania fit regional tectonic constraints and support the ‘out-of-Australia’ vicariance hypothesis. The Banggai-Sula region of the Sula Spur, the Australian promontory colliding with West Sulawesi during the Miocene, is identified as a possible source area for the colonization of Sulawesi by the ancestor of Tylomelania. The molecular phylogeny also shows a rapid diversification of Tylomelania into eight major lineages with very little overlap in their distribution on the island. Haplotype networks provide further evidence for a strong spatial structure of genetic diversity in Tylomelania. Distribution boundaries of the major lineages do at best partially coincide with previously identified contact zones for other endemic species groups on Sulawesi. This pattern has likely been influenced by the poor dispersal capabilities and altitudinal distribution limits of this strict freshwater inhabitant. We suggest that late Miocene and Pliocene orogeny in large parts of Sulawesi has been the vicariant event driving primary diversification in Tylomelania. PMID:24971564

von Rintelen, Thomas; Stelbrink, Björn; Marwoto, Ristiyanti M.; Glaubrecht, Matthias

2014-01-01

121

Partial characterisation of high-molecular weight glycoconjugates in the trail mucus of the freshwater pond snail Lymnaea stagnalis  

Microsoft Academic Search

We have studied the glycoconjugates in trail mucus of the pond snail Lymnaea stagnalis. The mucus was dissolved with 6 M guanidinium hydrochloride (GuHCl) and the major component was comprised of very high-Mr glycoconjugates that were eluted in the void volume of a Sepharose CL-4B gel-filtration column. This high-Mr material was pooled and thereafter subjected to density gradient centrifugation first

Simon Ballance; Marj Howard; Keith N White; Catherine R McCrohan; David J Thornton; John K Sheehan

2004-01-01

122

Indirect effects of heavy metals on parasites may cause shifts in snail species compositions.  

PubMed

We studied the direct and indirect effects of pollution on the distributions and abundances of two closely related species of pulmonate freshwater snails. Physella columbiana is more numerous at heavy metal-polluted lakes, and Lymnaea palustris is more numerous at reference lakes. Both species are present at all sites, as are predatory bluegill sunfish (Lepomis macrochirus). The direct effects examined included the snails' growth and reproduction in both the presence and absence of heavy metals and their short-term survival when exposed to large concentrations of heavy metals. The indirect effects were the species' ability to elude capture by sunfish and the diversity and abundance of parasites within the snails. We found that heavy metals had little direct effect on growth and reproduction and that both species acquired similar levels of metals in their tissues. Interestingly, P. columbiana (the more abundant species in polluted lakes) actually exhibited higher recruitment in the absence of metals than did L. palustris (reference lakes). L. palustris has life history characteristics that favor increased growth and reduced reproduction. These characteristics resulted in decreased predation of adults by gape-limited predators and a greater ability to cope with heavy parasite burdens. P. columbiana exhibited slower growth, which resulted in increased predation although higher reproduction rates may compensate.The major effect of heavy metals on species distributions was indirect on the snails' parasites. Parasites appeared to be very susceptible to metals, and this resulted in lower parasite diversity and intensities at polluted sites for both species of snails. P. columbiana may only be able to outcompete L. palustris at polluted sites due to the indirect effects of heavy metals; the negative effect of heavy metals on parasites, and a proposed negative effect of metals on the foraging ability of sunfish that favors the faster-reproducing P. columbiana. PMID:12045872

Lefcort, H; Aguon, M Q; Bond, K A; Chapman, K R; Chaquette, R; Clark, J; Kornachuk, P; Lang, B Z; Martin, J C

2002-07-01

123

Heavy metal concentrations in the freshwater snail Biomphalaria alexandrina uninfected or infected with cercariae of Schistosoma mansoni and/or Echinostoma liei in Egypt: the potential use of this snail as a bioindicator of pollution.  

PubMed

In spite of using aquatic snails as bioindicators for water pollution, little attention has been paid to the effect of parasitism upon the concentration of heavy metals (Al, Cd, Cu, Fe, Mn, Pb and Zn) in these organisms. The present study therefore aimed to compare the concentrations of heavy metals in trematode-infected Biomphalaria alexandrina collected from Kafer Alsheikh and Menofia provinces, Egypt, with uninfected snails from the same sites, in order to assess the effect of parasitism on the use of these snails as bioindicators. The concentrations of heavy metals in the soft parts and shells of snails were measured by flame atomic absorption spectrometry. The results showed that the heavy metal profile in snails infected with Echinostoma liei was very different from that in snails infected with Schistosoma mansoni. The total concentration of heavy metals in E. liei-infected snails collected from Kafer Alsheikh or Menofia province was greater than in uninfected snails. In contrast, the total concentration of heavy metals in S. mansoni-infected snails was reduced compared with uninfected snails. In conclusion, the status of snails with respect to parasitic infection must be taken into consideration when these snails are used as bioindicators. PMID:23710821

Mostafa, O M S; Mossa, A-T H; El Einin, H M A

2014-12-01

124

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

PubMed

The presence of pesticides in the environment results in potential unwanted effects on non-target species. Freshwater organisms inhabiting water bodies adjacent to agricultural areas, such as ditches, ponds and marshes, are good models to test such effects as various pesticides may reach these habitats through several ways, including aerial drift, run-off, and drainage. Diquat is a non-selective herbicide used for crop protection or for weed control in such water bodies. In this study, we investigated the effects of diquat on a widely spread aquatic invertebrate, the holarctic freshwater snail Lymnaea stagnalis. Due to the known redox-cycling properties of diquat, we studied transcript expression and enzymatic activities relative to oxidative and general stress in the haemolymph and gonado-digestive complex (GDC). As diquat is not persistent, snails were exposed for short times (5, 24, and 48 h) to ecologically relevant concentrations (22.2, 44.4, and 222.2 ?g l(-1)) of diquat dibromide. RT-qPCR was used to quantify the transcription of genes encoding catalase (cat), a cytosolic superoxide dismutase (Cu/Zn-sod), a selenium-dependent glutathione peroxidase (gpx), a glutathione reductase (gred), the retinoid X receptor (rxr), two heat shock proteins (hsp40 and hsp70), cortactin (cor) and the two ribosomal genes r18S and r28s. Enzymatic activities of SOD, Gpx, Gred and glutathione S-transferase (GST) were investigated in the GDC using spectrophoto/fluorometric methods. Opposite trends were obtained in the haemolymph depending on the herbicide concentration. At the lowest concentration, effects were mainly observed after 24 h of exposure, with over-transcription of cor, hsp40, rxr, and sod, whereas higher concentrations down-regulated the expression of most of the studied transcripts, especially after 48 h of exposure. In the GDC, earlier responses were observed and the fold-change magnitude was generally much higher: transcription of all target genes increased significantly (or non-significantly for cat) after 5 h of exposure, and went back to control levels afterwards, suggesting the onset of an early response to oxidative stress associated to the unbalance of reactive oxygen species (ROS) in hepatocytes. Although increases obtained for Gred and SOD activities were globally consistent with their respective transcript expressions, up-regulation of transcription was not always correlated with increase of enzymatic activity, indicating that diquat might affect steps downstream of transcription. However, constitutive levels of enzymatic activities were at least maintained. In conclusion, diquat was shown to affect expression of the whole set of studied transcripts, reflecting their suitability as markers of early response to oxidative stress in L. stagnalis. PMID:23237706

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

2013-01-15

125

Freshwater snails and schistosomiasis mansoni in the state of Rio de Janeiro, Brazil: V - Norte fluminense mesoregion  

Microsoft Academic Search

In this paper, the forth of a series dealing with the survey of freshwater gastropods of the state of Rio de Janeiro, the results of collections carried out in the Sul Fluminense Mesoregion from 2000 to 2002 are presented and revealed the occurrence of 18 species: Antillorbis nordestensis; Biomphalaria glabrata; Biomphalaria peregrina; Biomphalaria straminea; Biomphalaria tenagophila; Drepanotrema anatinum; Drepanotrema cimex;

Silvana C Thiengo; Aline C Mattos; M Fernanda Boaventura; Monica A Fernandez; Sonia B Santos

2004-01-01

126

Toxic effect of stem bark and leaf of Euphorbia hirta plant against freshwater vector snail Lymnaea acuminata.  

PubMed

The aqueous stem bark and leaf extracts of plant Euphorbia hirta (family-Euphorbiaceae) have potent molluscicidal activity. Sub-lethal doses (40% and 80% of LC50) of aqueous stem bark and leaf extracts of this plant also significantly (P<0.05) alter the levels of total protein, total free amino acid, nucleic acids (DNA and RNA) and the activity of enzyme protease and acid and alkaline phosphatase in various tissues of the vector snail Lymnaea acuminata in time and dose dependent manner. Euphorbia hirta (family-Euphorbiaceae) commonly known as Dudhi, is a common medicinal plant of India, which is used in variety of diseases i.e. cough, asthma, colic, dysentery, genito urinary diseases. PMID:15722098

Singh, Sunil Kumar; Yadav, Ram P; Tiwari, Sudhanshu; Singh, Ajay

2005-04-01

127

Disjunct distributions of freshwater snails testify to a central role of the Congo system in shaping biogeographical patterns in Africa  

PubMed Central

Background The formation of the East African Rift System has decisively influenced the distribution and evolution of tropical Africa’s biota by altering climate conditions, by creating basins for large long-lived lakes, and by affecting the catchment and drainage directions of river systems. However, it remains unclear how rifting affected the biogeographical patterns of freshwater biota through time on a continental scale, which is further complicated by the scarcity of molecular data from the largest African river system, the Congo. Results We study these biogeographical patterns using a fossil-calibrated multi-locus phylogeny of the gastropod family Viviparidae. This group allows reconstructing drainage patterns exceptionally well because it disperses very poorly in the absence of existing freshwater connections. Our phylogeny covers localities from major drainage basins of tropical Africa and reveals highly disjunct sister-group relationships between (a) the endemic viviparids of Lake Malawi and populations from the Middle Congo as well as between (b) the Victoria region and the Okavango/Upper Zambezi area. Conclusions The current study testifies to repeated disruptions of the distribution of the Viviparidae during the formation of the East African Rift System, and to a central role of the Congo River system for the distribution of the continent’s freshwater fauna during the late Cenozoic. By integrating our results with previous findings on palaeohydrographical connections, we provide a spatially and temporarily explicit model of historical freshwater biogeography in tropical Africa. Finally, we review similarities and differences in patterns of vertebrate and invertebrate dispersal. Amongst others we argue that the closest relatives of present day viviparids in Lake Malawi are living in the Middle Congo River, thus shedding new light on the origin of the endemic fauna of this rift lake. PMID:24597925

2014-01-01

128

Pulmonic Ingressive Speech in Shetland English  

ERIC Educational Resources Information Center

This paper presents a study of pulmonic ingressive speech, a severely understudied phenomenon within varieties of English. While ingressive speech has been reported for several parts of the British Isles, New England, and eastern Canada, thus far Newfoundland appears to be the only locality where researchers have managed to provide substantial…

Sundkvist, Peter

2012-01-01

129

Toxicity of Azadirachta indica to freshwater snails and fish, with reference to the physicochemical factor effect on potency.  

PubMed

A preliminary crude screening of plants in Jos Metropolis showed that at a concentration of 100 mg/l-1 the stem bark extract of the Neem plant Azadirachta indica caused a 100 percent mortality when tested against three common snail intermediate host species, Biomphalaria pfeifferi, Bulinus truncatus, and Lymnaea natalensis after 24 hours exposure. Toxicity test with freeze-dried aqueous extract of the plant gave 96 hours LC50 values of 19.00 mg/l-1 (p > 0.05), 10.96 mg/l-1 (p > 0.05) and 15.13 mg/l-1 (p > 0.05) against B. pfeifferi, B. truncatus and L. natalensis, respectively. When a similar test was carried out on fish, Aphyosemon giardneri a 96 hour LC50 of 15.1 mg/l-1 was recorded. Extraction with alcohol, increase in temperature within the optimal range, increase in acidity of aquatic medium and cold storage improved the potency of the extract while boiling and room storage reduced it. PMID:8508220

Osuala, F O; Okwuosa, V N

1993-02-01

130

Partial characterisation of high-molecular weight glycoconjugates in the trail mucus of the freshwater pond snail Lymnaea stagnalis.  

PubMed

We have studied the glycoconjugates in trail mucus of the pond snail Lymnaea stagnalis. The mucus was dissolved with 6 M guanidinium hydrochloride (GuHCl) and the major component was comprised of very high-M(r) glycoconjugates that were eluted in the void volume of a Sepharose CL-4B gel-filtration column. This high-M(r) material was pooled and thereafter subjected to density gradient centrifugation first in 4 M GuHCl/CsCl and subsequently 0.2 M GuHCl/CsCl to further remove non-glycosylated proteins and DNA. The harvested glycoconjugate pool chromatographed in the void volume of Sepharose CL-2B. However, reduction of disulfide bonds lowered the molecular size of approximately 80% of the void material yielding a major fragment and some minor smaller fragments in gel chromatography. The reduced glycoconjugates were digested with papain and yielded high molecular weight, proteinase-resistant glycopeptides. This fragmentation pattern is similar to that found for oligomeric gel-forming mucins in mammals and the amino acid composition (60% Ser/Thr) and sugar analysis of the glycopeptides is consistent with mucin-like molecules, there being no significant amounts of xylose or uronic acids. The residual 20% of the preparation, which apparently resisted reduction and protease digestion, had a similar amino acid composition to the bulk, but was somewhat different in sugar composition, containing some xylose and a significant amount of glucuronic acid. The two groups of molecules had very different morphologies in the electron microscope. Taken together, these data suggest that trail mucus is a complex mixture of at least two families of protein-glycoconjugate molecules based upon the gel-forming mucin and proteoglycan families, though we cannot rule out that polysaccharides may also be present. PMID:15081999

Ballance, Simon; Howard, Marj; White, Keith N; McCrohan, Catherine R; Thornton, David J; Sheehan, John K

2004-04-01

131

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

USGS Publications Warehouse

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.

Stoiber, Tasha L.; Croteau, Marie-Noele; Romer, Isabella; Tejamaya, Mila; Lead, Jamie R.; Luoma, Samuel N.

2015-01-01

132

Correlation between snails and fish in fish ponds of World Fish Center (ICLARM) with special reference to snail vectors of schistosomiasis and fascioliasis.  

PubMed

The abundance of snail species in earthen fish ponds, irrigation and drainage canals at World Fish Center (ICLARM) in descending order was Bellamya unicolor (50.89%) > Physa acuta (18.94%) > Cleopatra bulimoides (7.6%) > Lanistes carinatus (6.73%) > Bulinus truncatus (5.19%) > Melanoides tuberculata (4.83%) > Lymnaea natalensis (3.14%) > Gabbiella senaariensis (0.9%) > Biomphalaria alexandrina (0.55%) > Lym naea truncatula (0.4%) > Planorbis planorbis and Succinea cleopatra (0.33%) > Ferrissia isseli (0.18%). Dead snails constituted about 5.19% of all the collected specimens. There were dramatic decrease in the total number of pulmonates in fish ponds which contained only Tilapia sp., and a very small number of cat fish, whereas the numbers of prosobranchia snails were much higher in these ponds. In fish ponds which accommodated a variety of fish species, the most dominant snail was B. unicolor followed by L. carinatus. However, pulmonate snails were absent in these ponds. B. truncatus was the only snail species found in concrete tank which contained only young tilapias with a very small size (5-8 cm in standard length). In irrigation canals, the number of snails and diversity was much higher than those in fish ponds. Out of 191 snails collected from inlet irrigation canal, 71 were dead, but in the outside irrigation canals, seven out of 564 snails were dead. P. acuta was absent in all examined fish ponds, but it was alive and in a high number (497 snails) in the outside irrigation canals. The number of snails collected from Bahnasawy drain was remarkably low (128 snails), however the diversity of snails was much higher compared to those in fish ponds and irrigation canals. Snail populations were stable with constant recruitment of young to adult snails for all the studied species. PMID:14964656

Ismail, Nahed M M; El Gamal, Abd El Rahman A

2003-08-01

133

Digenean trematode infections of native freshwater snails and invasive Potamopyrgus antipodarum in the Grand Teton National Park/John D. Rockefeller Memorial Parkway Area.  

PubMed

Outside its native range, the invasive New Zealand mud snail (NZMS), Potamopyrgus antipodarum, is rarely reported to harbor parasites. To test this observation, 7 sites along the Snake River and Polecat Creek in the Grand Teton National Park/John D Rockefeller Memorial Parkway area (Wyoming) were surveyed for native aquatic snails, NZMS, and associated digenean trematodes, in July 2005. At 6 sites, native snails harbored patent digenean infections; within 2 hr, < or =10% of lymnaeid snails shed furcocercariae or xiphidiocercariae, and < or =42% of physid snails released furcocercariae or echinostome cercariae. Partial 18S rDNA sequences were recovered from several furcocercariae. Potamopyrgus antipodarum was present at, and collected from, 5 sites. Polymerase chain reaction assays targeting digenean rDNA sequences in DNA extracted from pools of 150 NZMS snails did not detect parasites. The examination of 960 NZMS by overnight shedding yielded 1 occurrence of (surface-encysted) metacercariae of an unclassified notocotylid (based on 18S and 28S rDNA sequences). The dissection of 150 ethanol-fixed NZMS (30/site) revealed 2 types of digenean metacercariae encysted in tissues of 5 snails from Polecat Creek. Thus, invasive NZMS may serve as first and second intermediate host for digenean parasites. PMID:18576875

Adema, C M; Lun, C-M; Hanelt, B; Seville, R S

2009-02-01

134

Field heritabilities and lack of correlation of snail shell form and anti-predator function  

E-print Network

species, the fish Herichthys minckleyi, is also endemic to the valley. We studied the free-ranging snailField heritabilities and lack of correlation of snail shell form and anti-predator function and performance. Organisms: A freshwater aquatic snail species, the Mexican banded spring snail Mexipyrgus

DeWitt, Thomas J.

135

Biological Control of Aquatic Pest Snails by the Black Carp Mylopharyngodon piceus  

Microsoft Academic Search

Some freshwater snail species are severe pests to human health or agriculture. We tested the hypothesis that the fish Mylopharyngodon piceus, the black carp, may serve as a biological control agent of two pest snails, Physella acuta (a bank-dwelling snail) and Melanoides tuberculata (a substratum-dwelling snail). Experiments were carried out in the laboratory and under controlled field conditions. In the

Frida Ben-Ami; Joseph Heller

2001-01-01

136

Water snails  

NSDL National Science Digital Library

Water snails have a shell for protection. They have two tentacles, a foot, and a head and a tail region. Water snails have eyes at the base of their sensory stalks. The stalks are used to smell and feel around the snail's environment.

Scott Bauer (USDA; ARS)

2005-08-03

137

Antioxidant defenses and metabolic depression. The hypothesis of preparation for oxidative stress in land snails  

Microsoft Academic Search

The roles of enzymatic antioxidant defenses in the natural tolerance of environmental stresses that impose changes in oxygen availability and oxygen consumption on animals is discussed with a particular focus on the biochemistry of estivation and metabolic depression in pulmonate land snails. Despite reduced oxygen consumption and PO2 during estivation, which should also mean reduced production of oxyradicals, the activities

Marcelo Hermes-Lima; Janet M. Storey; Kenneth B. Storey

1998-01-01

138

Metal-metallothioneins like proteins investigation by heteroatom-tagged proteomics in two different snails as possible sentinel organisms of metal contamination in freshwater ecosystems.  

PubMed

Metal speciation analysis in MLPs was carried out in two snails, Marisa cornuarietis and Pomacea bridgesi, in order to investigate them as possible sentinel organisms of heavy metal contamination. To carry out this study snails born in a non-contaminated environment were divided into two groups: a control group and a contaminated one with cadmium administered for 40 days. Subsequently, we investigated the speciation of the induced MLPs in exposed animals in relation to controls. In order to obtain the MLP fraction, cytosols from both snail species where subjected to size-exclusion fractionation, monitoring on-line the metal signal (Cd, Cu and Zn) by ICP-MS while protein elution was followed by on-line UV detection. MLP fraction was then separated by anion-exchange (AE)-FPLC using optimal chromatographic conditions for the separation of the different MLP isoforms in both snail species. Specific detection of separated metalloforms was carried out again by the hyphenation of the AE chromatographic system with ICP-MS. The determination of the amount of metal bound to MLPs was carried out by post-column isotope dilution analysis ICP-MS, finding that the snail M. cornuarietis accumulated higher concentrations of cadmium than P. bridgesi. Thus this first snail could therefore be a better candidate sentinel organism of pollution in natural waters. Identification and characterization of the isoforms separated in M. cornuarietis was carried out for the entire or intact isoforms by MALDI-TOF and then conventional triptic digestion was also carried out to identify the nature of the formed peptides. The presence identification of a MLP isoform of relatively low molecular weight in M. cornuarietis is reported. PMID:19720198

Maltez, Heloisa França; Villanueva Tagle, Margarita; Fernández de la Campa, Maria del Rosario; Sanz-Medel, Alfredo

2009-09-21

139

A Somatically Diversified Defense Factor, FREP3, Is a Determinant of Snail Resistance to Schistosome Infection  

Microsoft Academic Search

Schistosomiasis, a neglected tropical disease, owes its continued success to freshwater snails that support production of prolific numbers of human-infective cercariae. Encounters between schistosomes and snails do not always result in the snail becoming infected, in part because snails can mount immune responses that prevent schistosome development. Fibrinogen-related protein 3 (FREP3) has been previously associated with snail defense against digenetic

Patrick C. Hanington; Michelle A. Forys; Eric S. Loker

2012-01-01

140

Aquatic Toxicology 128129 (2013) 6066 Contents lists available at SciVerse ScienceDirect  

E-print Network

predicts full life-cycle toxicity effects of lead in the freshwater pulmonate snail, Lymnaea stagnalis Reproductive endpoints Lymnaea stagnalis Water quality criteria a b s t r a c t The freshwater pulmonate snail, Lymnaea stagnalis, is the most sensitive freshwater organism tested to date for several metals (Co, Cu, Pb

Grosell, Martin

141

Snails home  

NASA Astrophysics Data System (ADS)

Many gardeners and horticulturalists seek non-chemical methods to control populations of snails. It has frequently been reported that snails that are marked and removed from a garden are later found in the garden again. This phenomenon is often cited as evidence for a homing instinct. We report a systematic study of the snail population in a small suburban garden, in which large numbers of snails were marked and removed over a period of about 6 months. While many returned, inferring a homing instinct from this evidence requires statistical modelling. Monte Carlo techniques demonstrate that movements of snails are better explained by drift under the influence of a homing instinct than by random diffusion. Maximum likelihood techniques infer the existence of two groups of snails in the garden: members of a larger population that show little affinity to the garden itself, and core members of a local garden population that regularly return to their home if removed. The data are strongly suggestive of a homing instinct, but also reveal that snail-throwing can work as a pest management strategy.

Dunstan, D. J.; Hodgson, D. J.

2014-06-01

142

Adaptive plasticity in predator-induced defenses in a common freshwater snail: altered selection and mode of predation due to prey phenotype  

Microsoft Academic Search

Studies of putatively adaptive plasticity, such as inducible defenses, frequently explore the fitness consequences of expressing\\u000a alternative phenotypes in alternative environments, but few studies examine how and why the pattern of selection changes in relation to trait induction. We induced snails in the presence\\/absence of nonlethal predatory\\u000a crayfish, exposed both phenotypes (alone and combined) to selection by lethal crayfish, and

Josh R. Auld; Rick A. Relyea

2011-01-01

143

Escape and survival of Corophium volutator and Ilyanassa obsoleta exposed to freshwater and chlorothalonil  

Microsoft Academic Search

The behavioural response and survival of marine mud snails and mud shrimp exposed to freshwater and the fungicide chlorothalonil (tetrachloroisophthalonitrile) was investigated. Amphipods were less tolerant of lower salinity than snails, with 50 and 76% survival associated with 5 and 0% seawater in freshwater, respectively. However, 50% of snails displayed a defence mechanism by retracting within their shell when exposed

J. Hellou; A. Cook; B. Lalonde; P. Walker; K. Dunphy; S. MacLeod

2009-01-01

144

Snail Shell  

USGS Multimedia Gallery

Plant seems to be a Heliotropum sp. Huge snail shells litter the wetland around Asuncion Bay. Near 25°15’49’’S, 57°37’47’’W. La plantita detrás del caracol parece ser un Heliotropium sp., Boraginaceae....

145

Supercharged Snails for Stream Ecology & Water-Quality Studies  

ERIC Educational Resources Information Center

Gill-breathing freshwater snails (Family "Pleuroceridae") are ecologically important, abundant in many streams in the United States, and easy to collect and maintain under classroom conditions. These snails can be used in classroom tests to demonstrate effects of pollutants on aquatic organisms. In more advanced classes, students can cage the…

Stewart, Arthur J.; Ryon, Michael G.

2003-01-01

146

Distribution of freshwater snails in family-based VAC ponds and associated waterbodies with special reference to intermediate hosts of fish-borne zoonotic trematodes in Nam Dinh Province, Vietnam.  

PubMed

Fish-borne zoonotic trematodes, such as Clonorchis sinensis, heterophyids and others, constitute a public health concern in parts of northern Vietnam and infections with these trematodes are often thought to be linked to fish culture. One common fish culture system is the integrated fish-livestock (VAC) ponds where individual households have 1 or more ponds. Fish fry, mainly of various carp species, produced in hatcheries, not necessarily local, are introduced into nursery ponds and after approximately 6 weeks, juvenile fishes are transferred to household ponds, referred to as grow-out ponds. Grow-out ponds are usually fertilized with organic debris, including animal excreta, to stimulate algal growth and subsequently fish growth. This paper describes the distribution of freshwater snails and occurrence of trematode infections in these in VAC ponds and associated habitats as part of a major study on risk factors of FZT infections in cultured fish in two communes, Nghia Lac and Nghia Phu, Nghia Hung District, Nam Dinh Province. The area is under intense rice cultivation with an extensive canal network supplying fields and also household VAC ponds. A total of 16 snail species was found and four were widely distributed i.e. Angulyagra polyzonata, Melanoides tuberculata, Bithynia fuchsiana and Pomacea insularum. Snail diversity and counts were higher in nursery ponds than in grow-out ponds. Species of the families Thiaridae and Viviparidae were more abundant than other species in VAC ponds while species of the Bithyniidae, Stenothyridae and Planorbidae dominated in rice fields and small canals. Trematode infections were found in eight snail species and among these M. tuberculata had the highest overall prevalence of infection (13.28%). No trematode infections were found in species of the Viviparidae and Ampullaridae except for metacercariae. Parapleurolophocercous and pleurolophocercous cercariae constituted the most common type of cercariae recovered, contributing 40.6% of all infections followed by echinostome cercariae (35.0%) and xiphidiocercariae (17.3%). Bithynia fuschiana and M. tuberculata had the most diverse trematode fauna. C. sinensis was not recorded in this study. The VAC pond system in this area, is very important for transmission of minute intestinal trematodes while they play little role in transmission of C. sinensis as its intermediate hosts, bithynid snails, rarely occur in these ponds. From a public health perspective this is positive as the effects of infections with intestinal trematodes are considered mild. On the other hand it is possible that even such subtle effects could have importance in public health as transmission is very intense in the area. And this in combination with the aquaculture importance, reduced marketability of fishes with high metacercariae loads, warrants that control efforts against these trematodes are initiated to reduce transmission in this production system. PMID:20457118

Dung, Bui Thi; Madsen, Henry; The, Dang Tat

2010-10-01

147

Snails and trematode infection after Indian Ocean tsunami in Phang-Nga Province, southern Thailand.  

PubMed

The tsunami and non-tsunami affected areas of Takua Pa District, Phang-Nga Province were investigated for fresh- and brackish-water snails that transmit human parasitic diseases during 2006 and 2007. Among 46 snail species found, 17 species of 8 families were freshwater snails, 28 species of another 7 families were brackish-water snails, and 1 species was a land snail. Of these species, 11 freshwater snails, 4 brackish-water snails and 1 land snail were of medical importance. The fresh-water snails were Pomacea canaliculata, Pila angelica, P. gracilis, P. polita, Filopaludina (S.) martensi, F. (F.) s. polygramma, Melanoides tuberculata, Indoplanorbis exuxtus, Radix rubiginosa, Helicorbis umbilicalis, Gyraulus convexiusculus. Four brackish-water snails were Cerithidea cingulata, C. djadjarensis, C. alata, Sermyla riqueti and Achatina fulica was the land snail. I. exutus, M. tuberculata and F. (F.) s. polygramma harbored Xiphidio, Microcercus, Furocercus, Echinostome cercariae, and cercaria without eyespots or tail with hair. Three species of brackish-water snails, Cerithidia cingulata, C. djadjariensis, and C. alata presented with 6 types of trematode cercariae and rediae. Knowledge of medically important snails and their parasitic diseases, and prevention were given to Takua Pa people by poster, pamphlets and broadcasting through community radio. PMID:20578482

Sri-Aroon, Pusadee; Chusongsang, Phiraphol; Chusongsang, Yupa; Pornpimol, Surinthwong; Butraporn, Piyarat; Lohachit, Chantima

2010-01-01

148

First evidence of “paralytic shellfish toxins” and cylindrospermopsin in a Mexican freshwater system, Lago Catemaco, and apparent bioaccumulation of the toxins in “tegogolo” snails ( Pomacea patula catemacensis)  

Microsoft Academic Search

Exposure to cyanobacterial toxins in freshwater systems, including both direct (e.g., drinking water) and indirect (e.g., bioaccumulation in food webs) routes, is emerging as a potentially significant threat to human health. We investigated cyanobacterial toxins, specifically cylindrospermopsin (CYN), the microcystins (MCYST) and the “paralytic shellfish toxins” (PST), in Lago Catemaco (Veracruz, Mexico). Lago Catemaco is a tropical lake dominated by

John P. Berry; Owen Lind

2010-01-01

149

Why are there few algae on snail shells? The effects of grazing, nutrients and shell chemistry on the algae on shells of Helisoma trivolvis  

Microsoft Academic Search

SUMMARY 1. Freshwater snails often lack visible growths of algae on their shells. We tested three possible mechanisms that may account for this (grazing, snail-derived nutrients and chemical defences), using the ramshorn snail Helisoma trivolvis. 2. The experiments were carried out in floating plastic enclosures in a pond and comprised seven treatments. Grazing treatments were: a lone snail (ungrazed, as

LINDSEY L. ABBOTT; ELIZABETH A. BERGEY

2007-01-01

150

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

PubMed

Effects of the bipyridylium herbicide diquat and tank-mix adjuvant Agral90 were investigated on various life history traits of the freshwater pulmonate snail Lymnaea stagnalis. Trait expression was measured in simple laboratory bioassays on small size groups of snails, and under more complex, indoor microcosm conditions, on larger groups of snails. Microcosms were provided with sediment, plants, and fish, thus allowing a more complex level of intra and inter-specific interactions to develop. Treatments were performed with substances alone or in mixture, at concentrations ranging from 4.4 to 222.2microgl(-1) for diquat, and from 10 to 500microgl(-1) for Agral 90, under a fixed ratio design. Adult growth was negatively affected by diquat and its mixture with Agral 90 both at the highest concentrations (222.2 and 500microgl(-1), respectively). Fecundity expressed differently in bioassays and microcosms, but no effect of the chemicals could be observed on this trait. Progeny development was impaired by 222.2microgl(-1) diquat and its mixture with 500microgl(-1) Agral 90, as reflected by longer development time and reduced hatching rate of clutches laid by the exposed animals, as compared to the controls. Hatching data suggested that diquat bioavailability was lower in microcosms than under bioassay conditions. Consistently, chemical analysis showed that diquat disappeared more rapidly from the water in microcosms than in bioassays. Moreover, the differential expression of several life history traits under bioassays and microcosms conditions was probably also influenced by the level of intraspecific interaction, which differed among the systems. When significant, the effect of diquat was attenuated by the presence of Agral 90, indicating antagonistic interaction between the two substances. Such a deviation from additivity was partly validated statistically. PMID:18656229

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

2008-09-01

151

Complex interactions among fish, snails and macrophytes: implications for biological control of an invasive snail  

Microsoft Academic Search

The golden apple snail (Pomacea canaliculata), a native of freshwater wetlands of South America, has invaded many Asian countries and grazed heavily in agricultural and\\u000a wild areas. Common carp (Cyprinus carpio) has been proposed as a biological control agent against this snail, but little is known about its impact on non-target aquatic\\u000a plants and animals. In a 8-week enclosure experiment,

Pak Ki Wong; King Lun Kwong; Jian-Wen Qiu

2009-01-01

152

Aquatic Toxicology 106107 (2012) 147156 Contents lists available at SciVerse ScienceDirect  

E-print Network

of lead toxicity to the freshwater pulmonate snail, Lymnaea stagnalis Kevin V. Brixa,b, , Andrew J Received in revised form 11 November 2011 Accepted 15 November 2011 Keywords: Gastropods Lymnaea stagnalis Lead Calcium Feeding rates a b s t r a c t The freshwater pulmonate snail, Lymnaea stagnalis

Grosell, Martin

153

Fecundity of the Chinese mystery snail in a Nebraska reservoir  

USGS Publications Warehouse

The Chinese mystery snail (Bellamya chinensis) is a non-indigenous, invasive species in freshwater ecosystems of North America. We provide fecundity estimates for a population of these snails in a Nebraska reservoir. We dissected 70 snails, of which 29 were females. Nearly all female snails contained developing young, with an average of 25 young per female. Annual fecundity was estimated at between 27.2 and 33.3 young per female per year. Based on an estimated adult population and the calculated fecundity, the annual production for this reservoir was between 2.2 and 3.7 million young.

Stephen, Bruce J.; Allen, Craig R.; Chaine, Noelle M.; Fricke, Kent A.; Haak, Danielle M.; Hellman, Michelle L.; Kill, Robert A.; Nemec, Kristine T.; Pope, Kevin L.; Smeenk, Nicholas A.; Uden, Daniel R.; Unstad, Kody M.; VanderHam, Ashley E.; Wong, Alec

2013-01-01

154

Freshwater Mollusks Survive Fish Gut Passage  

Microsoft Academic Search

Freshwater mollusks figure prominently in the diets of humpback whitefish (Coregonus pidschian) and broad whitefish (C. nasus), two benthic-feeding coregonid species. A recent examination of pea clams (Sphaeriidae), valve snails (Valvatidae), and pond snails (Lymnaeidae) from the lower digestive tracts of these fish found that many of the mollusks were alive. Survival completely through gut passage would indicate a dispersal

RANDY J. BROWN

155

The annual reproductive cycle of the snail Megalobulimus abbreviatus (Bequaert, 1948) (Gastropoda, Pulmonata).  

PubMed

Morphological changes in the sexual organs of the pulmonates were observed throughout a year and correlated with reproductive-cycle periods. Reproductive-organ weights of the snail Megalobulimus abbreviatus were recorded seasonally and gonad sections were analyzed morphologically. The weights were used to obtain the organosomatic index. Mean oocytic diameter and oocytic maturation index were based on gonad sections. It was concluded that M. abbreviatus is an iteroparous snail whose annual reproductive cycle is characterized by mating and egg laying throughout spring and early summer, and also by reproductive system preparation, occurring over the remainder of the summer until the end of winter, for a new breeding season. PMID:16341424

Horn, A C M; Achaval, A; Zancan, D M

2005-08-01

156

Cercarial Dermatitis Transmitted by Exotic Marine Snail  

PubMed Central

Cercarial dermatitis (swimmer’s itch) is caused by the penetration of human skin by cercariae of schistosome parasites that develop in and are released from snail hosts. Cercarial dermatitis is frequently acquired in freshwater habitats, and less commonly in marine or estuarine waters. To investigate reports of a dermatitis outbreak in San Francisco Bay, California, we surveyed local snails for schistosome infections during 2005–2008. We found schistosomes only in Haminoea japonica, an Asian snail first reported in San Francisco Bay in 1999. Genetic markers place this schistosome within a large clade of avian schistosomes, but do not match any species for which there are genetic data. It is the second known schistosome species to cause dermatitis in western North American coastal waters; these species are transmitted by exotic snails. Introduction of exotic hosts can support unexpected emergence of an unknown parasite with serious medical or veterinary implications. PMID:20735918

Cohen, Andrew N.; James, David; Hui, Lucia; Hom, Albert; Loker, Eric S.

2010-01-01

157

CHANGES IN NUCLEAR HISTONES DURING FERTILIZATION, AND EARLY EMBRYONIC DEVELOPMENT IN THE PULMONATE SNAIL, Helix aspersa.  

PubMed

Calf thymus histories comprising two fractions, one rich in lysine, the other having roughly equal amounts of lysine and arginine, Loligo testes histones rich in arginine, and salmine, are compared with respect to their amino acid compositions, and their staining properties when the proteins are fixed on filter paper. The three types of basic proteins; somatic, arginine-rich spermatid histones, and protamine can be distinguished on the following basis. Somatic and testicular histones stain with fast green or bromphenol blue under the same conditions used for specific staining of histones in tissue preparations. The former histones lose most or all of their stainability after deamination or acetylation. Staining of the arginine-rich testicular histones remains relatively unaffected by this treatment. Protamines do not stain with fast green after treatment with hot trichloracetic acid, but are stained by bromphenol blue or eosin after treatment with picric acid. These methods provide a means for the characterization of nuclear basic proteins in situ. Their application to the early developmental stages of Helix aspersa show the following: After fertilization the protamine of the sperm is lost, and is replaced by faintly basic histones which differ from adult histones in their inability to bind fast green, and from protamines, by both their inability to bind eosin, and their weakly positive reaction with bromphenol blue. These "cleavage" histones are found in the male and female pronuclei, the early polar body chromosomes, and the nuclei of the cleaving egg and morula stages. During gastrulation, the histone complement reverts to a type as yet indistinguishable from that of adult somatic cells. PMID:19866570

Bloch, D P; Hew, H Y

1960-09-01

158

Dragonfly predators influence biomass and density of pond snails  

Microsoft Academic Search

Studies in lakes show that fish and crayfish predators play an important role in determining the abundance of freshwater snails.\\u000a In contrast, there are few studies of snails and their predators in shallow ponds and marshes. Ponds often lack fish and crayfish\\u000a but have abundant insect populations. Here we present the results of field surveys, laboratory foraging trials, and an

Andrew M. Turner; Michael F. Chislock

2007-01-01

159

Pedal sole immunoreactive axons in terrestrial pulmonates: Limax, Arion, and Helix.  

PubMed

A century ago histological techniques such as formic acid-gold chloride showed the nerve morphology of the pedal sole in Limax and Helix. There have been no similar descriptions since then of the central nervous system relevant to locomotory pedal waves in the foot of slugs and snails. Topical application of 5-HT affects locomotory waves, but the innervation of the pedal sole with 5-HT axons is not known. Three-dimensional morphology of pedal axons in terrestrial pulmonate embryos is shown herein with modern histological techniques using antibodies and the confocal microscope. In Limax maximus, pedal ganglia are shown with Tritonia pedal peptide (TPep) antibodies. Ladder-like cross bridges in the pedal sole are shown with antibodies to both TPep and 5-HT. In Arion ater, pedal ganglia neurons and their axons that form a plexus in the pedal sole are shown with 5-HT antibodies. In Helix aspersa, 5-HT immunoreactive pedal ganglia neurons and a developing pedal sole axon plexus are seen as in A. ater. Axons in this plexus that grow across the pedal sole can be seen growing into pre-existing nerves. No peripheral 5-HT neurons were identified in these three species. This immunoreactive plexus to 5-HT antibodies in A. ater and H. aspersa spreads over the pedal sole epithelium. Axons immunoreactive to 5-HT antibodies in A. ater and H. aspersa extend the length of the foot, primarily in the rim, so that activity in these axons cannot provide local patterned input to produce locomotory waves, but may provide modulatory input to pedal sole muscles. PMID:24648204

Longley, Roger D

2014-02-01

160

Species- and size-specific infection of snails by Cyclocoelum mutabile (Digenea: Cyclocoelidae).  

PubMed

Infectivity of Cyclocoelum mutabile miracidia to 9 species and up to 4 size classes of pulmonate snails at 14, 16, and 20 C was studied under laboratory conditions. Of the 9 species examined, 6 (Stagnicola elodes, Lymnaea stagnalis, Gyraulus parvus, Gyraulus circumstriatus, Promenetus exacuous, and Armiger crista) were highly susceptible (infection success > or = 25%), 2 (Physa jennessi and Helisoma trivolvis) had low susceptibility (infection success < 25%, > 0), and 1 (Physa gyrina) was not susceptible to infection. Within highly susceptible species, snail size was negatively related to susceptibility and temperature had variable effects. Infection success was not affected by temperature or snail size in species with low susceptibility. Production of cercariae was negatively correlated with susceptibility among snails of different sizes and species, but was not influenced by snail size for a given species. Among species, metacercariae production was typically higher in lymnaeids than in either planorbids or physids. Results of experiments where miracidia were provided with a choice of 2 different snails suggest that they do not discriminate between species with high and low susceptibility. PMID:7623190

McKindsey, C W; McLaughlin, J D

1995-08-01

161

Self-Fertilization and Genetic Population Structure in a Colonizing Land Snail  

PubMed Central

The pulmonate land snail Rumina decollata in its native Mediterranean range is a complex of monogenic or weakly polygenic strains generated by a breeding system of facultative self-fertilization. One strain colonized North America and now occupies much of the southern United States and northern Mexico. No genetic variation within or among populations in the United States was detected in an electrophoretic analysis of proteins encoded by 25 loci. These findings emphasize the potential for adaptive convergence in the genetic systems of hermaphroditic animals and plants. PMID:16592078

Selander, Robert K.; Kaufman, Donald W.

1973-01-01

162

Ten new complete mitochondrial genomes of pulmonates (Mollusca: Gastropoda) and their impact on phylogenetic relationships  

PubMed Central

Background Reconstructing the higher relationships of pulmonate gastropods has been difficult. The use of morphology is problematic due to high homoplasy. Molecular studies have suffered from low taxon sampling. Forty-eight complete mitochondrial genomes are available for gastropods, ten of which are pulmonates. Here are presented the new complete mitochondrial genomes of the ten following species of pulmonates: Salinator rhamphidia (Amphiboloidea); Auriculinella bidentata, Myosotella myosotis, Ovatella vulcani, and Pedipes pedipes (Ellobiidae); Peronia peronii (Onchidiidae); Siphonaria gigas (Siphonariidae); Succinea putris (Stylommatophora); Trimusculus reticulatus (Trimusculidae); and Rhopalocaulis grandidieri (Veronicellidae). Also, 94 new pulmonate-specific primers across the entire mitochondrial genome are provided, which were designed for amplifying entire mitochondrial genomes through short reactions and closing gaps after shotgun sequencing. Results The structural features of the 10 new mitochondrial genomes are provided. All genomes share similar gene orders. Phylogenetic analyses were performed including the 10 new genomes and 17 genomes from Genbank (outgroups, opisthobranchs, and other pulmonates). Bayesian Inference and Maximum Likelihood analyses, based on the concatenated amino-acid sequences of the 13 protein-coding genes, produced the same topology. The pulmonates are paraphyletic and basal to the opisthobranchs that are monophyletic at the tip of the tree. Siphonaria, traditionally regarded as a basal pulmonate, is nested within opisthobranchs. Pyramidella, traditionally regarded as a basal (non-euthyneuran) heterobranch, is nested within pulmonates. Several hypotheses are rejected, such as the Systellommatophora, Geophila, and Eupulmonata. The Ellobiidae is polyphyletic, but the false limpet Trimusculus reticulatus is closely related to some ellobiids. Conclusions Despite recent efforts for increasing the taxon sampling in euthyneuran (opisthobranchs and pulmonates) molecular phylogenies, several of the deeper nodes are still uncertain, because of low support values as well as some incongruence between analyses based on complete mitochondrial genomes and those based on individual genes (18S, 28S, 16S, CO1). Additional complete genomes are needed for pulmonates (especially for Williamia, Otina, and Smeagol), as well as basal heterobranchs closely related to euthyneurans. Increasing the number of markers for gastropod (and more broadly mollusk) phylogenetics also is necessary in order to resolve some of the deeper nodes -although clearly not an easy task. Step by step, however, new relationships are being unveiled, such as the close relationships between the false limpet Trimusculus and ellobiids, the nesting of pyramidelloids within pulmonates, and the close relationships of Siphonaria to sacoglossan opisthobranchs. The additional genomes presented here show that some species share an identical mitochondrial gene order due to convergence. PMID:21985526

2011-01-01

163

Crawling beneath the free surface: Water snail locomotion  

E-print Network

Land snails move via adhesive locomotion. Through muscular contraction and expansion of their foot, they transmit waves of shear stress through a thin layer of mucus onto a solid substrate. Since a free surface cannot support shear stress, adhesive locomotion is not a viable propulsion mechanism for water snails that travel inverted beneath the free surface. Nevertheless, the motion of the freshwater snail, Sorbeoconcha physidae, is reminiscent of that of its terrestrial counterparts, being generated by the undulation of the snail foot that is separated from the free surface by a thin layer of mucus. Here, a lubrication model is used to describe the mucus flow in the limit of small amplitude interfacial deformations. By assuming the shape of the snail foot to be a traveling sine wave and the mucus to be Newtonian, an evolution equation for the interface shape is obtained and the resulting propulsive force on the snail is calculated. This propulsive force is found to be non-zero for moderate values of Capillary number but vanishes in the limits of high and low Capillary numbers. Physically, this force arises because the snail's foot deforms the free surface, thereby generating curvature pressures and lubrication flows inside the mucus layer that couple to the topography of the foot.

Sungyon Lee; John W. M. Bush; A. E. Hosoi; Eric Lauga

2008-06-23

164

Copper toxicity to the fresh water snail, Lymnaea luteola  

SciTech Connect

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.

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

1987-07-01

165

Neurogenesis in the procerebrum of the snail Helix aspersa: a quantitative analysis.  

PubMed

The procerebrum, a specialized structure for olfaction in terrestrial pulmonate molluscs, contains 20,000 to 50,000 small, uniformly sized neurons that increase in number with age. Here I show the likely source of neurons added to the procerebrum of Helix aspersa and that the rate of neuron addition depends on snail weight. After hatching, during the initial exponential growth phase, H. aspersa adds neurons to the procerebral apex by mitosis and from a cerebral tube. In the logistic growth phase beginning 30-40 days post-hatch, neurons also seem to be added to the procerebrum from the peritentacular and olfactory nerves, causing the rate of neuron addition to approximately double; but as in the earlier exponential growth phase, this rate remains a function of snail weight. This neuron addition throughout the life of the snail can be predicted by snail weight. In the two growth phases, the number of neurons in the procerebrum is given by logarithmic functions of snail weight. The results here for H. aspersa provide the basis for experiments to determine the peripheral origin and destination of neuronal precursors that are added to the procerebrum and to determine how neuron addition affects the function of the procerebrum. PMID:22042440

Longley, Roger D

2011-10-01

166

Snail Shell Science.  

ERIC Educational Resources Information Center

Presents three inquiry-based lessons to develop the science process skills of observation, identification, and classification. Activities use whelk eggs and snail shells as the focus of the students' inquiries. Provides a list of 19 facts about whelks and snails. (MDH)

Matthews, Catherine

1992-01-01

167

Genetics, Shell Morphology, and Life History of the Freshwater Pulmonate Limpets Ferrissia rivularis and Ferrissia fragilis  

Microsoft Academic Search

The weak and variable nature of the shell morphometric criteria by which the North American ancylid limpets Ferrissia rivularis and Ferrissia fragilis are distinguished has led to speculation that they may be ecophenotypic variants. The shells of F. rivularis that we collected from a rocky river in the upper piedmont of South Carolina were significantly higher and wider per length

Robert T. Dillon Jr; Jacob J. Herman

2009-01-01

168

Life cycle stages of heterophyid trematodes in Vietnamese freshwater fishes traced by molecular and morphometric methods  

Microsoft Academic Search

A survey of digenean zoonotic trematodes infecting snails and fishes in a North Vietnamese freshwater fish culture system revealed shedding of three types of parapleurolophocercous cercariae from the snail host Melanoides tuberculata and the presence of metacercariae within the genus Haplorchis (H. pumilio and H. taichui) and Procerovum sp. in tissues of cultured fishes (silver carp, Indian carp and climbing

Jakob Skov; Per W. Kania; Anders Dalsgaard; Thomas R. Jørgensen; Kurt Buchmann

2009-01-01

169

Population Differences in Effects of Fish on Physa integra Refuge Use  

Microsoft Academic Search

Prey populations exposed to different sets of predators often adopt distinct antipredator behaviors. We investigated the refuge use of a freshwater pulmonate snail, Physa integra, in the presence and absence of fish predators. Over 80% of snails in sites with fish used refuge, while only 50% used refuge in sites without fish. Snails in sites with fish were also significantly

RANDALL J. BERNOT; KYLE WHITTINGHILL

2003-01-01

170

Population estimate of Chinese mystery snail (Bellamya chinensis) in a Nebraska reservoir  

USGS Publications Warehouse

The Chinese mystery snail (Bellamya chinensis) is an aquatic invasive species in North America. Little is known regarding this species' impacts on freshwater ecosystems. It is be lieved that population densities can be high, yet no population estimates have been reported. We utilized a mark-recapture approach to generate a population estimate for Chinese mystery snail in Wild Plum Lake, a 6.47-ha reservoir in southeast Nebraska. We calculated, using bias-adjusted Lincoln-Petersen estimation, that there were approximately 664 adult snails within a 127 m2 transect (5.2 snails/m2). If this density was consistent throughout the littoral zone (<3 m in depth) of the reservoir, then the total adult population in this impoundment is estimated to be 253,570 snails, and the total Chinese mystery snail wet biomass is estimated to be 3,119 kg (643 kg/ha). If this density is confined to the depth sampled in this study (1.46 m), then the adult population is estimated to be 169,400 snails, and wet biomass is estimated to be 2,084 kg (643 kg/ha). Additional research is warranted to further test the utility of mark-recapture methods for aquatic snails and to better understand Chinese mystery snail distributions within reservoirs.

Chaine, Noelle M.; Allen, Craig R.; Fricke, Kent A.; Haak, Danielle M.; Hellman, Michelle L.; Kill, Robert A.; Nemec, Kristine T.; Pope, Kevin L.; Smeenk, Nicholas A.; Stephen, Bruce J.; Uden, Daniel R.; Unstad, Kody M.; VanderHam, Ashley E.

2012-01-01

171

Maternal Inheritance of racemism in the terrestrial snail Bradybaena similaris.  

PubMed

In metazoan animals, almost every known mutation of visceral asymmetry, which presents the polarity of primary asymmetry established in early development, reverses development in only about half or fewer of homozygotes. However, in pulmonate snails, the dextral and sinistral alleles are traditionally known to determine the polarity of offspring with complete dominance, and thus, each parent should produce either dextral or sinistral progeny. Contrary to this expectation, we found a mutant that produces both chiral morphs (enantiomorphs) within the same clutches in Bradybaena similaris. This study demonstrates that the consistent production of both enantiomorphs is determined by a maternal effect of a recessive allele, which probably randomizes the polarity. In snails that copulate simultaneously and reciprocally, a left-right reversed strain cannot usually be established or rescued from inbreeding depression by ad hoc outbreeding because a rarely found single mutant cannot reproduce due to great difficulties of mating with the wild type and selfing. Moreover, the rare recessive homozygote cannot easily be detected because it often exhibits the wild-type phenotype in maternal inheritance and breeding difficulty hampers genotyping it by phenotyping its progeny. The present strain established by virtue of rare advantages will, therefore, provide unique opportunities to investigate whole-body enantiomorphs. PMID:19617526

Utsuno, Hiroki; Asami, Takahiro

2010-01-01

172

Streptococcus Constellatus Community Acquired Pneumonia with Subsequent Isolated Pulmonic Valve Endocarditis and Abscess Formation in a Structurally Normal Heart  

PubMed Central

Pulmonic valve infective endocarditis in isolation is a rare clinical entity. The formation of an abscess in the right ventricular outflow tract as a consequence of vegetations affecting the pulmonic valve in a structurally normal heart is extremely rare and has not been reported. We report a case of isolated pulmonic valve endocarditis complicated by a regional abscess formed within the right ventricular outflow tract caused by Streptococcus Constellatus (S. Constellatus), a member of the Streptococcus Milleri group in a young male whose risk factor was alcohol abuse and he was treated medically, a comprehensive literature review on the subject is also reported. Our case is the first reported in literature with infective endocarditis caused by S. Constellatus affecting the pulmonic valve, and the first with pulmonic valve endocarditis and perivalvular abscess formation in a structurally normal heart. PMID:25031801

Hutchison, Stuart James

2014-01-01

173

Hitchhiking behaviour in the obligatory upstream migration of amphidromous snails  

PubMed Central

Migratory animals endure high stress during long-distance travel in order to benefit from spatio-temporally fluctuating resources, including food and shelter or from colonization of unoccupied habitats. Along with some fishes and shrimps, nerite snails in tropical to temperate freshwater systems are examples of amphidromous animals that migrate upstream for growth and reproduction after a marine larval phase. Here I report, to my knowledge, the first example of ‘hitchhiking’ behaviour in the obligatory migration of animals: the nerite snail Neritina asperulata appears to travel several kilometres as minute juveniles by firmly attaching to the shells of congeneric, subadult snails in streams of Melanesian Islands, presumably to increase the success rate of migration. PMID:19411267

Kano, Yasunori

2009-01-01

174

UNEP: Freshwater  

NSDL National Science Digital Library

This searchable site, from The United Nations Environment Programme, is a clearinghouse for information about freshwater around the globe. The site provides links to UN reports, background guides on key freshwater issues, and many other resources.

The United Nations Environment Programme (UNEP)

175

RELATIVE EFFECTS OF PREDATION AND FACILITATION IN CONTROLLING THE DISTRIBUTION AND GROWTH OF AN INTERTIDAL PULMONATE SNAIL  

EPA Science Inventory

The results will allow managers to better predict potential effects of eutrophication and predator depletion (e.g., recent declines in crab populations) on salt marsh structure and function and to formulate effective long-term plans to sustain this resource....

176

Serotonergic immunoreactivity in the pedal ganglia of the pulmonate snail Megalobulimus abbreviatus after thermal stimulus: A semi-quantitative analysis.  

PubMed

Using an immunohistochemical procedure and optical densitometry, the distribution of neurons containing serotonin (5-HT) was investigated in the pedal ganglia of Megalobulimus abbreviatus after thermal "non-functional stimulus" (22 degrees C) and stressful thermal conditions (50 degrees C). The animals were sacrificed at different times (3 h, 6 h and 24 h) following these stimuli. In control animals, the results showed the location of these serotonergic immunoreactive elements (5HT-ir) in this ganglion to be similar to those shown in other studies, where the anterior region of ventral sections showed the largest number of 5HT-ir neurons. In the anterior neurons, significant differences (p < 0.01) were observed between the groups of animals stimulated at 50 degrees C and 22 degrees C and sacrificed after 6 h. In the medial neurons, significant differences (p < 0.05) were observed between the control group and the groups of animals stimulated at 50 degrees C and sacrificed after 6 and 24 h. Neuropilar area 1 showed differences (p < 0.01) in 5HT-ir between the control group and the groups of animals stimulated at 50 degrees C and sacrificed after 3 and 24 h. Neuropilar area 2 showed a significant difference (p < 0.05) between the groups of animals stimulated at 22 degrees C and sacrificed after 3 and 24 h. These results suggest the involvement of 5-HT in the nociceptive circuit of M. abbreviatus, mainly that of the medial neurons and neuropilar area 1, which showed increases in 5HT-ir after thermal aversive stimuli. These results could be helpful in drawing cellular homologies with other gastropods. PMID:15979914

Swarowsky, A; Monteiro, A F; Xavier, L L; Zancan, D M; Achaval, M

2005-06-01

177

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

USGS Publications Warehouse

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 Jind?ich?v Hradec and T?ebo? 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.

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

2012-01-01

178

A GUIDE TO FRESHWATER MOLLUSKS OF THE LAURENTIAN GREAT LAKES WITH SPECIAL EMPHASIS ON THE GENUS PISIDIUM  

EPA Science Inventory

Presented here are keys and notes on distribution and ecology for the freshwater snails (Gastropoda), mussels (Unionidae), and fingernail clams (Sphaeriidae) which have been collected from the Laurentian Great Lakes. Including subspecies and forms, 121 taxa are discussed: 47 Gast...

179

[Orientation of the cleavage spindles in pulmonate mollusks. I. The role of the form of the blastomeres in 2d cleavage spindle orientation].  

PubMed

In the normal two-celled embryos of various pulmonate molluscs, the orientation of spindles characteristic of metaanaphase is being frequently established gradually, in the process of transition from pro- to metaphase accompained by the growth of spindle and asters. The typical growth of contact zone between the blastomeres of the common pond snail embryos was inhibited to a different extent under their cultivation after the 1 cleavage division in the calcium-free media or after trypsinization. At the same time the orientation of meta-anaphase spindles was markedly affected (as judged by an angle alpha between the spindle axis and the plane of contact zone in the equatorial projection). When analyzing the model distributions of the angles between the two spindle axes (in the same projection), it was shown that the empirical distributions of these angles corresponded to the principle of stochastic combination of two alpha. A conclusion is drawn that the orientation of one spindle does not depend on that of another but the position of each of them depends on the size of the contact zone and, hence, on the general form of the adjacent blastomere region. Some other processes determining the spindle orientation are discussed. PMID:569264

Meshcheriakov, V N

1978-01-01

180

Lichen endozoochory by snails.  

PubMed

Endozoochory plays a prominent role for the dispersal of seed plants. However, for most other plant taxa it is not known whether this mode of dispersal occurs at all. Among those other taxa, lichens as symbiotic associations of algae and fungi are peculiar as their successful dispersal requires movement of propagules that leaves the symbiosis functional. However, the potential for endozoochorous dispersal of lichen fragments has been completely overlooked. We fed sterile thalli of two foliose lichen species (Lobaria pulmonaria and Physcia adscendens) differing in habitat and air-quality requirements to nine snail species common in temperate Europe. We demonstrated morphologically that L. pulmonaria regenerated from 29.0% of all 379 fecal pellets, whereas P. adscendens regenerated from 40.9% of all 433 fecal pellets, showing that lichen fragments survived gut passage of all snail species. Moreover, molecular analysis of regenerated lichens confirmed the species identity for a subset of samples. Regeneration rates were higher for the generalist lichen species P. adscendens than for the specialist lichen species L. pulmonaria. Furthermore, lichen regeneration rates varied among snail species with higher rates after gut passage of heavier snail species. We suggest that gastropods generally grazing on lichen communities are important, but so far completely overlooked, as vectors for lichen dispersal. This opens new ecological perspectives and questions the traditional view of an entirely antagonistic relationship between gastropods and lichens. PMID:21533256

Boch, Steffen; Prati, Daniel; Werth, Silke; Rüetschi, Jörg; Fischer, Markus

2011-01-01

181

Lichen Endozoochory by Snails  

PubMed Central

Endozoochory plays a prominent role for the dispersal of seed plants. However, for most other plant taxa it is not known whether this mode of dispersal occurs at all. Among those other taxa, lichens as symbiotic associations of algae and fungi are peculiar as their successful dispersal requires movement of propagules that leaves the symbiosis functional. However, the potential for endozoochorous dispersal of lichen fragments has been completely overlooked. We fed sterile thalli of two foliose lichen species (Lobaria pulmonaria and Physcia adscendens) differing in habitat and air-quality requirements to nine snail species common in temperate Europe. We demonstrated morphologically that L. pulmonaria regenerated from 29.0% of all 379 fecal pellets, whereas P. adscendens regenerated from 40.9% of all 433 fecal pellets, showing that lichen fragments survived gut passage of all snail species. Moreover, molecular analysis of regenerated lichens confirmed the species identity for a subset of samples. Regeneration rates were higher for the generalist lichen species P. adscendens than for the specialist lichen species L. pulmonaria. Furthermore, lichen regeneration rates varied among snail species with higher rates after gut passage of heavier snail species. We suggest that gastropods generally grazing on lichen communities are important, but so far completely overlooked, as vectors for lichen dispersal. This opens new ecological perspectives and questions the traditional view of an entirely antagonistic relationship between gastropods and lichens. PMID:21533256

Boch, Steffen; Prati, Daniel; Werth, Silke; Rüetschi, Jörg; Fischer, Markus

2011-01-01

182

Small Snails, Enormous Elephants  

NSDL National Science Digital Library

This activity (located on page 2 of PDF) introduces learners to the real size of animals using nonstandard measurement. Learners use Unifix cubes and yarn lengths to measure a variety of animals (photos), from the very small like a snail to the very large like an elephant. As an extension, learners can use the cubes to create a bar graph depicting the animals' lengths.

2012-06-26

183

Pleistocene glaciation is implicated in the phylogeographical structure of Potamopyrgus antipodarum , a New Zealand snail  

Microsoft Academic Search

Pleistocene glaciation has been identified as an important factor shaping present-day patterns of phylogeographical structure in a diverse array of taxa. The purpose of this study was to use mitochondrial sequence data to address whether Pleistocene glaciation is also a major determinant of phylogeographical patterns in Potamopyrgus antipodarum , a freshwater snail native to New Zealand. We found that haplotypes

MAURINE NEIMAN; CURTIS M. L IVELY

184

Fish predation and offspring survival in the prosobranch snail Viviparus ater  

Microsoft Academic Search

In this study we identified some of the predators of the freshwater snail Viviparus ater and estimated offspring survival to the end of the first summer in a natural population. Newborn V. ater were eaten by the fish Barbus barbus, Rutilus rutilus, Scardinius erythrophtalmus and Tinca tinca. Out of 137 guts of Abramis brama caught in Lake Zürich 1 contained

G. Keller; G. Ribi

1993-01-01

185

The ecology of vector snail habitats and mosquito breeding-places  

PubMed Central

The ecology of freshwater snails—in particular those which act as intermediate hosts of bilharziasis—is reviewed in the light of the much more extensive knowledge available on the breeding-places of anopheline mosquitos. Experimental ecological methods are recommended for the field and laboratory investigation of a number of common problems involved in the study of snail habitats and mosquito breeding-places. Among the environmental factors discussed are temperature, oxygen concentration, water movement, pollution and salinity. Sampling methods for estimating populations of both snails and mosquito larvae are also described. An attempt is made to show how malacologists and entomologists alike would benefit from improved facilities for keeping abreast of general developments in the wider field of freshwater ecology. PMID:13596888

Muirhead-Thomson, R. C.

1958-01-01

186

Characterization of the pigmented shell-forming proteome of the common grove snail Cepaea nemoralis  

PubMed Central

Background With a diversity of pigmented shell morphotypes governed by Mendelian patterns of inheritance, the common grove snail, Cepaea nemoralis, has served as a model for evolutionary biologists and population geneticists for decades. Surprisingly, the molecular mechanisms by which C. nemoralis generates this pigmented shelled diversity, and the degree of evolutionary conservation present between molluscan shell-forming proteomes, remain unknown. Results Here, using next generation sequencing and high throughput proteomics, we identify and characterize the major proteinaceous components of the C. nemoralis shell, the first shell-proteome for a pulmonate mollusc. The recent availability of several marine molluscan shell-proteomes, and the dataset we report here, allow us to identify 59 evolutionarily conserved and novel shell-forming proteins. While the C. nemoralis dataset is dominated by proteins that share little to no similarity with proteins in public databases, almost half of it shares similarity with proteins present in other molluscan shells. In addition, we could not find any indication that a protein (or class of proteins) is directly associated with shell pigmentation in C. nemoralis. This is in contrast to the only other partially characterized molluscan-shell pigmentation mechanism employed by the tropical abalone Haliotis asinina. Conclusions The unique pulmonate shell-forming proteome that we report here reveals an abundance of both mollusc-specific and pulmonate-specific proteins, suggesting that novel coding sequences, and/or the extensive divergence of these sequences from ancestral sequences, supported the innovation of new shell types within the Conchifera. In addition, we report here the first evidence that molluscs use independently evolved mechanisms to pigment their shells. This proteome provides a solid foundation from which further studies aimed at the functional characterization of these shell-forming proteins can be conducted. PMID:24684722

2014-01-01

187

Effects of Endocrine Disruptors on Prosobranch Snails (Mollusca: Gastropoda) in the Laboratory. Part I: Bisphenol A and Octylphenol as Xeno-Estrogens  

Microsoft Academic Search

The effects of suspected endocrine disrupting chemicals on freshwater and marine prosobranch species were analysed in laboratory experiments. In this first publication, the responses of the freshwater snail Marisa cornuarietis and of the marine prosobranch Nucella lapillus to the xeno-estrogenic model compounds bisphenol A (BPA) and octylphenol (OP) are presented at nominal concentration ranges between 1 and 100 µg\\/L. Marisa

Jörg Oehlmann; Ulrike Schulte-Oehlmann; Michaela Tillmann; Bernd Markert

2000-01-01

188

Eye to Eye With Garden Snails  

NSDL National Science Digital Library

This Snail Unit encourages students to explore the external characteristics and behavior of snails. It effectively gets students past the "ugh, slime" reaction to recognizing individual differences in snails and challenges students to learn enough about the snail to be able to predict their behavior under a variety of conditions. Detailed observations are requested as are preparation and testing of hypotheses. This unit works very well with all levels of students and with heterogeneously grouped students. This Snail Unit consists of six lessons: (1) Introduction to a Snail (2) How do snails move? How fast is a snail's pace? (3) What and how do snails eat? (4) Are snails attracted to, or repelled by particular substances? (5) Can snails be enticed to travel faster or in a certain direction? (6) How are snails like other animals? How are they different?

BEGIN:VCARD VERSION:2.1 FN:Kathy Liu N:Liu; Kathy ORG:Access Excellence REV:2005-04-19 END:VCARD

1994-07-30

189

Freshwater Blooms  

NSDL National Science Digital Library

This Bigelow Laboratory "Special Topics" page discusses freshwater harmful algal blooms (HABs). The interactive web page describes the features of a freshwater HAB with a focus on location, organisms affected, human symptoms, toxins (neurotoxins and hepatotoxins), and causative organisms. Links are provided to other pages within the Toxic and Harmful Algal Blooms collection.

Bigelow Laboratory for Ocean Sciences

190

Baldomero Olivera: Cone Snail Peptides  

NSDL National Science Digital Library

Have you ever considered the venom of a snail? Most people think of snakes when they think of venom but overlook snails. There are, however, almost 10,000 species of venomous predatory snails according to this engaging lecture from Professor Baldomero Olivera. In his talk, Professor Olivera explores how these venoms have been used to understand the nervous system and develop new drugs. The lecture is divided into three different sections, and visitors shouldn't miss Part 2 ("How a Fish Hunting Snail Captures Its Prey"). Visitors are also welcome to download the entire lecture and the accompanying slides.

Olivera, Baldomero

191

Metal distribution and metallothionein induction after cadmium exposure in the terrestrial snail Helix aspersa (Gastropoda, Pulmonata).  

PubMed

The aim of the present work was to study the effect of Cd2+ exposure on metallothionein (MT) induction and on the distribution of metals (Cd, Cu, and Zn) in the terrestrial pulmonate Helix aspersa. In particular, the soluble and nonsoluble pools of the accumulated metals and their tissue distribution in uncontaminated and contaminated edible snails were investigated after a two-week exposure to Cd2+. In the soluble cytosolic pool of the midgut gland of H. aspersa, three metal-specific putative MT isoforms were separated following a fractionation protocol with diethylaminoethyl cellulose, size-exclusion chromatography, ultrafiltration, and reversed-phase high-performance liquid chromatography (RP-HPLC). Interestingly, one of the above isoforms seems to bind both Cd and Cu, which may in addition mobilize, after induction by Cd2+, some of the intracellular Cu and, thus, perhaps increase the Cu pool in the cytosolic fraction. The cDNA and its translated amino acid sequence of a Cd2+-binding MT isoform from the snail midgut gland was characterized and attributed to one of the putative MT isoforms obtained by RP-HPLC. The amino acid sequence of this Cd-MT isoform of H. aspersa differed from similar sequences described in other terrestrial pulmonates, such as Helix pomatia or Arianta arbustorum, by only a few amino acids (n = 4 and 8, respectively). That the identified Cd-MT from H. aspersa is inducible by Cd2+ also was shown, chromatographic evidence aside, by a specific polymerase chain reaction protocol on a cDNA basis, which included a noninducible housekeeping gene as a control. PMID:18384240

Hispard, Florian; Schuler, Dietmar; de Vaufleury, Annette; Scheifler, Renaud; Badot, Pierre-Marie; Dallinger, Reinhard

2008-07-01

192

Aquatic Toxicology 91 (2009) 302311 Contents lists available at ScienceDirect  

E-print Network

nmol g-1 h-1 ) than in comparably sized fish in similar water chemistry. Under control conditions of the freshwater pulmonate snail, Lymnaea stagnalis, to chronic lead exposure Martin Grosella, , Kevin V. Brixa form 16 October 2008 Accepted 22 October 2008 Keywords: Lead Snails Ionoregulation Biotic ligand model

Grosell, Martin

193

Notocotylus biomphalariae n. sp. (Digenea: Notocotylidae)from Biomphalaria peregrina (Gastropoda: Pulmonata) in Patagonia, Argentina  

Microsoft Academic Search

A new species of Notocotylus was found parasiting a freshwater pulmonate snail, Biomphalaria peregrina. Naturally infected snails were collected from two temporary ponds in the Nahuel Huapí National Park in Patagonia. The characteristics of the larval stages are presented. Experimental adults were recovered from the intestinal caeca of ducks and chicks. Adults of Notocotylus biomphalariae n. sp. exhibit an aspinose

Verónica Flores; Norma Brugni

2005-01-01

194

Plasma N-Terminal Pro B-Type Natriuretic Peptide Concentrations in Dogs with Pulmonic Stenosis  

PubMed Central

ABSTRACT The detailed information between plasma N-terminal pro B-type natriuretic peptide (NT-proBNP) concentrations and dogs with pulmonic stenosis (PS) is still unknown. The aim of the present study was to investigate the clinical utility of measuring plasma NT-proBNP concentrations in dogs with PS and to determine whether plasma NT-proBNP concentration could be used to assess disease severity. This retrospective study enrolled 30 client-owned, untreated dogs with PS (asymptomatic [n=23] and symptomatic [n=7]) and 11 healthy laboratory beagles. Results of physical examination, thoracic radiography and echocardiography were recorded. Plasma NT-proBNP concentrations were measured using commercial laboratories. Compared to the healthy control dogs, cardiothoracic ratio was significantly increased in dogs with both asymptomatic and symptomatic PS. Similarly, the ratio of the main pulmonary artery to aorta was significantly decreased in dogs with both asymptomatic and symptomatic PS. The pulmonic pressure gradient in the symptomatic PS dogs was significantly higher than that in the asymptomatic PS dogs. Plasma NT-proBNP concentration was significantly elevated in the symptomatic PS dogs compared to the healthy control dogs and the asymptomatic PS dogs. Furthermore, the Doppler-derived pulmonic pressure gradient was significantly correlated with the plasma NT-proBNP concentration (r=0.78, r2=0.61, P<0.0001). Plasma NT-proBNP concentration >764 pmol/l to identify severe PS had a sensitivity of 76.2% and specificity of 81.8%. The plasma NT-proBNP concentration increased by spontaneous PS, i.e. right-sided pressure overload and can be used as an additional method to assess the severity of PS in dogs. PMID:24561377

KOBAYASHI, Keiya; HORI, Yasutomo; CHIMURA, Syuuichi

2014-01-01

195

Impact of invasive apple snails on the functioning and services of natural and managed wetlands  

NASA Astrophysics Data System (ADS)

At least 14 species of apple snail (Ampullariidae) have been released to water bodies outside their native ranges; however, less than half of these species have become widespread or caused appreciable impacts. We review evidence for the impact of apple snails on natural and managed wetlands focusing on those studies that have elucidated impact mechanisms. Significant changes in wetland ecosystems have been noted in regions where the snails are established: Two species in particular (Pomacea canaliculata and Pomacea maculata) have become major pests of aquatic crops, including rice, and caused enormous increases in molluscicide use. Invasive apple snails have also altered macrophyte community structure in natural and managed wetlands through selective herbivory and certain apple snail species can potentially shift the balance of freshwater ecosystems from clear water (macrophyte dominated) to turbid (plankton dominated) states by depleting densities of native aquatic plants. Furthermore, the introductions of some apple snail species have altered benthic community structure either directly, through predation, or indirectly, through exploitation competition or as a result of management actions. To date much of the evidence for these impacts has been based on correlations, with few manipulative field or mesocosm experiments. Greater attention to impact monitoring is required, and, for Asia in particular, a landscape approach to impact management that includes both natural and managed-rice wetlands is recommended.

Horgan, Finbarr G.; Stuart, Alexander M.; Kudavidanage, Enoka P.

2014-01-01

196

Parasites alter host phenotype and may create a new ecological niche for snail hosts  

PubMed Central

By modifying the behaviour and morphology of hosts, parasites may strongly impact host individuals, populations and communities. We examined the effects of a common trematode parasite on its snail host, Batillaria cumingi (Batillariidae). This widespread snail is usually the most abundant invertebrate in salt marshes and mudflats of the northeastern coast of Asia. More than half (52.6%, n=1360) of the snails in our study were infected. We found that snails living in the lower intertidal zone were markedly larger and exhibited different shell morphology than those in the upper intertidal zone. The large morphotypes in the lower tidal zone were all infected by the trematode, Cercaria batillariae (Heterophyidae). We used a transplant experiment, a mark-and-recapture experiment and stable carbon isotope ratios to reveal that snails infected by the trematode move to the lower intertidal zone, resume growth after maturation and consume different resources. By simultaneously changing the morphology and behaviour of individual hosts, this parasite alters the demographics and potentially modifies resource use of the snail population. Since trematodes are common and often abundant in marine and freshwater habitats throughout the world, their effects potentially alter food webs in many systems. PMID:16777719

Miura, Osamu; Kuris, Armand M; Torchin, Mark E; Hechinger, Ryan F; Chiba, Satoshi

2006-01-01

197

Integrating nonindigenous aquatic plant control with protection of snail kite nests in Florida.  

PubMed

The endangered snail kite (Rostrhamus sociabilis) feeds primarily on the freshwater apple snail (Pomacea paludosa) in Florida. The nonindigenous, floating water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) impede kites from finding snails. Effective control of these aquatic plants in the littoral zone of central and south Florida lakes benefits kites by maintaining open foraging habitat. However, incidental herbicide spraying of nesting substrates result in nest collapse when kites breed in nonwoody, emergent plants [cattail (Typha spp.) and giant bulrush (Scirpus validus)] in the outer littoral zone during lower lake levels. Many endangered species recovery plans and their implementation have experienced problems due to inaction and/or noncooperation by various governmental agencies and their personnel. Herein, we describe the development and implementation of a buffer zone strategy to prevent secondary impacts from an aquatic plant control program to snail kites nesting on lakes in central and south Florida. A strategy was jointly developed by personnel of five state and federal agencies to control herbicide application near kite nesting areas during the normal breeding season. Although requiring various modifications during its implementation, this cooperative effort successfully integrated aquatic plant control objectives with snail kite conservation on Lake Okeechobee during 1988. The program was expanded the following year to lakes Kissimmee and Tohopekaliga. Since the implementation of the snail kite impact preclusion program, no nest loss was attributed to incidental herbicide applications on lakes Okeechobee, Kissimmee, and Tohopekaliga. PMID:11436998

Rodgers, J A; Smith, H T; Thayer, D D

2001-07-01

198

METHODS FOR CONDUCTING SNAIL (APLEXA HYPNORUM) EMBRYO THROUGH ADULT EXPOSURES: EFFECTS OF CADMIUM AND REDUCED PH LEVELS  

EPA Science Inventory

Two separate embryo through adult exposures were conducted with cadmium and with reduced pH levels to validate various test methodologies and to determine the feasibility of testing and ease of handling the freshwater snail (Aplexa hypnorum) in a test system designed for fish bio...

199

Role of water and food in the entry of certain radionuclides into the organism of the pond snail  

Microsoft Academic Search

The aim of the present paper is to study the role of Elodea (Elodea canadensis Rich.) and the aquatic medium in accumulation of strontium-90, cesium-137, cerium-144, and ruthenium-106 by a freshwater aquatic gastropod, the pond snail Limnaea stagnalis L., under laboratory conditions. The mollusks were collected for investigation in boggy lakes in the Lithuanian SSR near Kurshkii Bay. Taking the

D. P. Marchyulenene; G. G. Polikarpov

1976-01-01

200

Cost of autotomy drives ontogenetic switching of anti-predator mechanisms under developmental constraints in a land snail  

PubMed Central

Autotomy of body parts offers various prey animals immediate benefits of survival in compensation for considerable costs. I found that a land snail Satsuma caliginosa of populations coexisting with a snail-eating snake Pareas iwasakii survived the snake predation by autotomizing its foot, whereas those out of the snake range rarely survived. Regeneration of a lost foot completed in a few weeks but imposed a delay of shell growth. Imprints of autotomy were found in greater than 10 per cent of S. caliginosa in the snake range but in only less than 1 per cent out of it, simultaneously demonstrating intense predation by the snakes and high efficiency of autotomy for surviving snake predation in the wild. However, in experiments, mature S. caliginosa performed autotomy less frequently. Instead of the costly autotomy, they can use defensive denticles on the inside of their shell apertures. Owing to the constraints from the additive growth of shells, most pulmonate snails can produce these denticles only when they have fully grown up. Thus, this developmental constraint limits the availability of the modified aperture, resulting in ontogenetic switching of the alternative defences. This study illustrates how costs of adaptation operate in the evolution of life-history strategies under developmental constraints PMID:23034702

Hoso, Masaki

2012-01-01

201

Red blood with blue-blood ancestry: Intriguing structure of a snail hemoglobin  

PubMed Central

The phylogenetic enigma of snail hemoglobin, its isolated occurrence in a single gastropod family, the Planorbidae, and the lack of sequence data, stimulated the present study. We present here the complete cDNA and predicted amino acid sequence of two hemoglobin polypeptides from the planorbid Biomphalaria glabrata (intermediate host snail for the human parasite Schistosoma mansoni). Both isoforms contain 13 different, cysteine-free globin domains, plus a small N-terminal nonglobin “plug” domain with three cysteines for subunit dimerization (total Mr ? 238 kDa). We also identified the native hemoglobin molecule and present here a preliminary 3D reconstruction from electron microscopical images (3 nm resolution); it suggests a 3 × 2-mer quaternary structure (Mr ? 1.43 MDa). Moreover, we identified a previously undescribed rosette-like hemolymph protein that has been mistaken for hemoglobin. We also detected expression of an incomplete hemocyanin as trace component. The combined data show that B. glabrata hemoglobin evolved from pulmonate myoglobin, possibly to replace a less-efficient hemocyanin, and reveals a surprisingly simple evolutionary mechanism to create a high molecular mass respiratory protein from 78 similar globin domains. PMID:16877545

Lieb, Bernhard; Dimitrova, Konstantina; Kang, Hio-Sun; Braun, Sabrina; Gebauer, Wolfgang; Martin, Andreas; Hanelt, Ben; Saenz, Steven A.; Adema, Coen M.; Markl, Jürgen

2006-01-01

202

Study of the diet effect on ? 13C of shell carbonate of the land snail Helix aspersa in experimental conditions  

NASA Astrophysics Data System (ADS)

This study aims to demonstrate the influence of the metabolic CO 2 derived from the diet and of the atmospheric CO 2 on the shell carbonate ? 13C of the pulmonate snail Helix aspersa maxima raised under controlled conditions. Adult snails were analyzed and compared with three hatching and 1-day old young snails stemming from the same breeding. One day after, the 2-day old individuals were raised during 1 month. Three groups of gastropods were fed with fresh lettuce (C 3 plant, ? 13C=-27.49‰), three groups with corn (C 4 plant, ? 13C=-11.7‰), and three groups ate alternately both (C 3+C 4). The difference between the average ? 13C values of the adult snails on the one hand and the hatched and 1-day old snails on the other hand indicates a depletion of 2.47‰. Therefore, the isotopic parents-offspring signal is not preserved. The depleted ingested albumen by the snail embryo in the egg during the building of the shell could explain this depletion. The C 3 diet experiment gave the expected isotopic composition difference between the diet (lettuce) and the shells (average ? 13C shell-lettuce=13.75‰±0.52). This result shows a clear diet effect on the isotopic composition of the snail shells. For the C 4 experiment, the difference in carbon isotope composition between the corn and the shell (? 13C shell-corn) yielded an average value of 4.89‰±0.87. The main result is that ? 13C is not constant and appears to depend on the type of ingested food. Several hypotheses can arise from this study to explain the different fractionations: (a) differences in the quality of the two diets, (b) differences in turnover rate for C 3 and C 4 feeders. The groups regularly fed with mixed diet yielded ? 13C values showing a preferential use of C 3 food for most values. The C 3-C 4 mixed dietary alternation probably led snails to use mainly the lettuce instead of the corn powder.

Metref, S.; Rousseau, D.-D.; Bentaleb, I.; Labonne, M.; Vianey-Liaud, M.

2003-06-01

203

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

SciTech Connect

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.

Woin, P.; Broenmark, C. (Univ. of Lund (Sweden))

1992-01-01

204

RNA-Seq Reveals Infection-Induced Gene Expression Changes in the Snail Intermediate Host of the Carcinogenic Liver Fluke, Opisthorchis viverrini  

PubMed Central

Background Bithynia siamensis goniomphalos is the snail intermediate host of the liver fluke, Opisthorchis viverrini, the leading cause of cholangiocarcinoma (CCA) in the Greater Mekong sub-region of Thailand. Despite the severe public health impact of Opisthorchis-induced CCA, knowledge of the molecular interactions occurring between the parasite and its snail intermediate host is scant. The examination of differences in gene expression profiling between uninfected and O. viverrini-infected B. siamensis goniomphalos could provide clues on fundamental pathways involved in the regulation of snail-parasite interplay. Methodology/Principal Findings Using high-throughput (Illumina) sequencing and extensive bioinformatic analyses, we characterized the transcriptomes of uninfected and O. viverrini-infected B. siamensis goniomphalos. Comparative analyses of gene expression profiling allowed the identification of 7,655 differentially expressed genes (DEGs), associated to 43 distinct biological pathways, including pathways associated with immune defense mechanisms against parasites. Amongst the DEGs with immune functions, transcripts encoding distinct proteases displayed the highest down-regulation in Bithynia specimens infected by O. viverrini; conversely, transcription of genes encoding heat-shock proteins and actins was significantly up-regulated in parasite-infected snails when compared to the uninfected counterparts. Conclusions/Significance The present study lays the foundation for functional studies of genes and gene products potentially involved in immune-molecular mechanisms implicated in the ability of the parasite to successfully colonize its snail intermediate host. The annotated dataset provided herein represents a ready-to-use molecular resource for the discovery of molecular pathways underlying susceptibility and resistance mechanisms of B. siamensis goniomphalos to O. viverrini and for comparative analyses with pulmonate snail intermediate hosts of other platyhelminths including schistosomes. PMID:24676090

Prasopdee, Sattrachai; Sotillo, Javier; Tesana, Smarn; Laha, Thewarach; Kulsantiwong, Jutharat; Nolan, Matthew J.

2014-01-01

205

Changes in gastropod assemblages in freshwater habitats in the vicinity of Basel (Switzerland) over 87 years  

Microsoft Academic Search

The gastropod fauna in 18 freshwater habitats (streams, rivers and ponds) in the vicinity of Basel, first surveyed in 1906\\/1907, was re-examined in 1994. The freshwater snail fauna changed considerably over 87 years. One species (Aplexa hypnorum) recorded in 1906\\/1907 was not found in 1994, most probably it had become extinct in the period between the two surveys. Ten species

Bruno Baur; Birgit Ringeis

2002-01-01

206

A Comparison of Freshwater Macroinvertebrate Communities on Small Caribbean Islands  

NSDL National Science Digital Library

This peer-reviewed article from BioScience is about freshwater macroinvetebrate communities. An ongoing survey of macroinvertebrates inhabiting the relatively unstudied freshwater habitats on 14 small Caribbean islands was initiated in 1991. These collections have yielded almost 200 species; when these species are combined with collections previously made by other researchers, a total of at least 328 freshwater macroinvertebrates are now known from these islands. The dominant taxa on the islands include several species of snails, shrimps, mayflies, dragonflies, damselflies, beetles, and other insects. Many of these species have fairly widespread distributions across the islands. Most stream species are associated with leaf packs, and most pond species are associated with aquatic macrophytes. As is typical of tropical island systems, the macroinvertebrate faunas of these islands are sparse, most likely because of their oceanic origin, their small size, and the frequent disturbances to their freshwater environments.

DAVID BASS (; )

2003-11-01

207

Freshwater Molluscs  

Microsoft Academic Search

Freshwater mollusc shells are among the best and most extensively preserved fossils in lacustrine sediments. These molluscs\\u000a are useful because they occur in a broad range of paleoenvironments. As a result, they have been used to reconstruct former\\u000a stream confluences, provide a basis for biostratigraphic zonation of sedimentary sequences in lake basins, and reconstruct\\u000a habitat and climatic conditions. Because many

Barry B. Miller; Michael J. S. Tevesz

208

Eradication of Slugs and Snails  

Microsoft Academic Search

IN the note on the ``Eradication of Slugs and Snails'' in NATURE of July 16, p. 90, reference is made to many of the accepted methods of dealing with these pests. The trouble with barriers of repellent material is that spreading plants such as violas, certain asters, carnations, etc., are difficult to surround without injurious contact to the foliage, and

A. H. Hall

1932-01-01

209

APPLE SNAILS AS DISEASE VECTORS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Apple snails (Ampullariidae) are intermediate hosts of parasites causing at least three diseases in humans: cercarial dermatitis (“swimmer’s itch”) caused by trematode cercaria, intestinal problems caused by flukes in the genus Echinostoma, and eosinophilic meningitis caused by the nematode Angiostr...

210

A case of left main systolic compression caused by a dilated pulmonary artery in a patient with congenital pulmonic stenosis.  

PubMed

Dynamic compression of the left main coronary artery during systole is extremely rare. We report a case of a 29-year old female who presented with shortness of breath and chest pain with exertion. She had a history of congenital pulmonic stenosis and had a pulmonary valve resection at age 2. She subsequently developed chronic pulmonic insufficiency. She had normal left ventricular systolic function and a dilated right ventricle with pressure and volume overload diagnosed by echocardiography. She had pulmonary artery hypertension with pulmonary artery pressures noted to be systolic of 62mmHg, diastolic of 10 mmHg, mean of 29 mmHg on right heart catheterization. Her echocardiogram also showed an elevated mean pulmonary artery pressure of 25 mmHg, which was thought to be due to increased flow. On left heart catheterization, she was found to have dynamic systolic compression of the left main coronary artery by a dilated pulmonary artery. This is the first case report of a patient with congenital pulmonic stenosis with a dilated pulmonary trunk causing systolic compression of the left main coronary artery. Dynamic systolic compression of the left main coronary artery is a rare cause of angina, is rarely reported, and requires a high level of suspicion and careful investigation for accurate diagnosis. PMID:21041858

Simmons, Ashley; Vacek, James; Gupta, Kamal

2010-11-01

211

Light-dependent and -independent behavioral effects of extremely low frequency magnetic fields in a land snail are consistent with a parametric resonance mechanism  

SciTech Connect

Exposure to extremely low frequency (ELF) magnetic fields has been shown to attenuate endogenous opioid peptide mediated antinociception or analgesia in the terrestrial pulmonate snail, Cepaea nemoralis. Here the authors examine the roles of light in determining this effect and address the mechanisms associated with mediating the effects of the ELF magnetic fields in both the presence and absence of light. Specifically, they consider whether the magnetic field effects involve an indirect induced electric current mechanism or a direct effect such as a parametric resonance mechanism (PRM). They exposed snails in both the presence and absence of light at three different frequencies (30, 60, and 120 Hz) with static field values (B{sub DC}) and ELF magnetic field amplitude (peak) and direction (B{sub AC}) set according to the predictions of the PRM for Ca{sup 2+}. Analgesia was induced in snails by injecting them with an enkephalinase inhibitor, which augments endogenous opioid (enkephalin) activity. They found that the magnetic field exposure reduced this opioid-induced analgesia significantly more if the exposure occurred in the presence rather than the absence of light. However, the percentage reduction in analgesia in both the presence and absence of light was not dependent on the ELF frequency. This finding suggests that in both the presence and the absence of light the effect of the ELF magnetic field was mediated by a direct magnetic field detection mechanism such as the PRM rather than an induced current mechanism.

Prato, F.S.; Thomas, A.W. [Univ. of Western Ontario, London, Ontario (Canada)] [Univ. of Western Ontario, London, Ontario (Canada); [St. Joseph`s Health Centre, London, Ontario (Canada); Kavaliers, M. [Univ. of Western Ontario, London, Ontario (Canada)] [Univ. of Western Ontario, London, Ontario (Canada); Cullen, A.P. [Univ. of Waterloo, Ontario (Canada). School of Optometry] [Univ. of Waterloo, Ontario (Canada). School of Optometry

1997-05-01

212

Light-dependent and -independent behavioral effects of extremely low frequency magnetic fields in a land snail are consistent with a parametric resonance mechanism.  

PubMed

Exposure to extremely low frequency (ELF) magnetic fields has been shown to attenuate endogenous opioid peptide mediated antinociception or "analgaesia" in the terrestrial pulmonate snail, Cepaea nemoralis. Here we examine the roles of light in determining this effect and address the mechanisms associated with mediating the effects of the ELF magnetic fields in both the presence and absence of light. Specifically, we consider whether the magnetic field effects involve an indirect induced electric current mechanism or a direct effect such as a parametric resonance mechanism (PRM). We exposed snails in both the presence and absence of light at three different frequencies (30, 60, and 120 Hz) with static field values (BDC) and ELF magnetic field amplitude (peak) and direction (BAC) set according to the predictions of the PRM for Ca2+. Analgaesia was induced in snails by injecting them with an enkephalinase inhibitor, which augments endogenous opioid (enkephalin) activity. We found that the magnetic field exposure reduced this opioid-induced analgaesia significantly more if the exposure occurred in the presence rather than the absence of light. However, the percentage reduction in analgaesia in both the presence and absence of light was not dependent on the ELF frequency. This finding suggests that in both the presence and the absence of light the effect of the ELF magnetic field was mediated by a direct magnetic field detection mechanism such as the PRM rather than an induced current mechanism. PMID:9096848

Prato, F S; Kavaliers, M; Cullen, A P; Thomas, A W

1997-01-01

213

Exploring Species Level Taxonomy and Species Delimitation Methods in the Facultatively Self-Fertilizing Land Snail Genus Rumina (Gastropoda: Pulmonata)  

PubMed Central

Delimiting species in facultatively selfing taxa is a challenging problem of which the terrestrial pulmonate snail genus Rumina is a good example. These snails have a mixed breeding system and show a high degree of shell and color variation. Three nominal species (R. decollata, R. saharica and R. paivae) and two color morphs within R. decollata (dark and light) are currently recognized. The present study aims at evaluating to what extent these entities reflect evolutionary diverging taxonomic units, rather than fixed polymorphisms due to sustained selfing. Therefore, a phylogenetic analysis of nuclear (ITS1, ITS2) and mitochondrial DNA (COI, CytB, 12S rDNA, 16S rDNA) sequences was performed. Putative species in Rumina, inferred from the mitochondrial DNA phylogeny, were compared with those proposed on the basis of the COI gene by (1) DNA barcoding gap analysis, (2) Automatic Barcode Gap Discovery, (3) the species delimitation plug-in of the Geneious software, (4) the Genealogical Sorting Index, and (5) the General Mixed Yule Coalescent model. It is shown that these methods produce a variety of different species hypotheses and as such one may wonder to what extent species delimitation methods are really useful. With respect to Rumina, the data suggest at least seven species, one corresponding to R. saharica and six that are currently grouped under the name R. decollata. The species-level status of R. paivae is rejected. PMID:23577154

Prévot, Vanya; Jordaens, Kurt; Sonet, Gontran; Backeljau, Thierry

2013-01-01

214

Regulation of laboratory populations of snails (Biomphalaria and Bulinus spp.) by river prawns, Macrobrachium spp. (Decapoda, Palaemonidae): implications for control of schistosomiasis  

PubMed Central

Human schistosomiasis is a common parasitic disease endemic in many tropical and subtropical countries. One barrier to achieving long-term control of this disease has been re-infection of treated patients when they swim, bathe, or wade in surface fresh water infested with snails that harbor and release larval parasites. Because some snail species are obligate intermediate hosts of schistosome parasites, removing snails may reduce parasitic larvae in the water, reducing re-infection risk. Here, we evaluate the potential for snail control by predatory freshwater prawns, Macrobrachium rosenbergii and M. vollenhovenii, native to Asia and Africa, respectively. Both prawn species are high value, protein-rich human food commodities, suggesting their cultivation may be beneficial in resource-poor settings where few other disease control options exist. In a series of predation trials in laboratory aquaria, we found both species to be voracious predators of schistosome-susceptible snails, hatchlings, and eggs, even in the presence of alternative food, with sustained average consumption rates of 12% of their body weight per day. Prawns showed a weak preference for Bulinus truncatus over Biomphalaria glabrata snails. Consumption rates were highly predictable based on the ratio of prawn: snail body mass, suggesting satiation-limited predation. Even the smallest prawns tested (0.5–2g) caused snail recruitment failure, despite high snail fecundity. With the World Health Organization turning attention toward schistosomiasis elimination, native prawn cultivation may be a viable snail control strategy that offers a win-win for public health and economic development. PMID:24388955

Lafferty, Kevin D.; Kuris, Armand M.

2014-01-01

215

Regulation of laboratory populations of snails (Biomphalaria and Bulinus spp.) by river prawns, Macrobrachium spp. (Decapoda, Palaemonidae): implications for control of schistosomiasis.  

PubMed

Human schistosomiasis is a common parasitic disease endemic in many tropical and subtropical countries. One barrier to achieving long-term control of this disease has been re-infection of treated patients when they swim, bathe, or wade in surface fresh water infested with snails that harbor and release larval parasites. Because some snail species are obligate intermediate hosts of schistosome parasites, removing snails may reduce parasitic larvae in the water, reducing re-infection risk. Here, we evaluate the potential for snail control by predatory freshwater prawns, Macrobrachium rosenbergii and M. vollenhovenii, native to Asia and Africa, respectively. Both prawn species are high value, protein-rich human food commodities, suggesting their cultivation may be beneficial in resource-poor settings where few other disease control options exist. In a series of predation trials in laboratory aquaria, we found both species to be voracious predators of schistosome-susceptible snails, hatchlings, and eggs, even in the presence of alternative food, with sustained average consumption rates of 12% of their body weight per day. Prawns showed a weak preference for Bulinus truncatus over Biomphalaria glabrata snails. Consumption rates were highly predictable based on the ratio of prawn: snail body mass, suggesting satiation-limited predation. Even the smallest prawns tested (0.5-2g) caused snail recruitment failure, despite high snail fecundity. With the World Health Organization turning attention toward schistosomiasis elimination, native prawn cultivation may be a viable snail control strategy that offers a win-win for public health and economic development. PMID:24388955

Sokolow, Susanne H; Lafferty, Kevin D; Kuris, Armand M

2014-04-01

216

Study of the diet effect on d13C of shell carbonate of the land snail Helix aspersa in experimental conditions  

NASA Astrophysics Data System (ADS)

This study aims to demonstrate the influence of the metabolic CO2 derived from the diet and of the atmospheric CO2 on the shell carbonate d13C of the pulmonate snail Helix aspersa maxima raised under controlled conditions. Adult snails were analyzed and compared with three hatching and one-day young snails stemming from the same breeding. One day after, the two-days old individuals were raised during one month. Three groups of gastropods were fed with fresh lettuce (C3 plant, d13C = -27.49 ppt), three groups with corn (C4 plant, d13C = -11.7 ppt), and three groups ate both (C3 + C4). The difference between the mean d13C values of the adult snails on one hand and the hatched and one-day snails on the other hand indicates a depletion of 2.47 ‰. Therefore, the isotopic parents offspring signal is not preserved. The depleted ingested albumen by the snail embryo in the egg during the built of the shell could explain this depletion. The C3 diet experiment gave the expected isotopic composition difference between the diet (lettuce) and the shells (mean D13Cshell-Lettuce = 13.75 ppt +- 0.52). This result shows a clear diet effect on the isotopic composition of the snail shells. For the C4 experiment, the difference in carbon isotope composition between the corn and the shell (D13Cshell-corn) yielded a mean value of 4.89 ppt +- 0.87. The main result is that D13C is not constant and appears to depend on the type of ingested food. Several hypothesis can raise from this study to explain the different fractionations : a) The differences in quality of the two diets seem to have placed the animals in different growth states, b) Differences in turnover rate for C3 and C4 feeders. The groups regularly fed with mixed diet yielded d13C values, showing a preferential use of C3 food for the most values. The C3-C4 mixed dietary alternation probably led snails to use mainly the lettuce instead of the corn powder.

Metref, S.; Rousseau, D. D.; Bentaleb, I.; Labonne, M.; Vianey-Liaud, M.

2003-04-01

217

Taxonomy: A Precursor to Understanding Ecological Interactions among Schistosomes, Snail Hosts, and Snail-Eating Fishes  

E-print Network

, and Snail-Eating Fishes JAY RICHARD STAUFFER, JR.* Pennsylvania State University, 420 Forest Resources decrease in the abundance of snail-eating fishes and an increase in the prevalence of schistosomiasis among decrease in fish molluscivores permitted an increase in the abundance of snails that are intermediate hosts

Boyer, Elizabeth W.

218

Salinity adaptation of the invasive New Zealand mud snail (Potamopyrgus antipodarum) in the Columbia River estuary (Pacific Northwest, USA): physiological and molecular studies  

USGS Publications Warehouse

In this study, we examine salinity stress tolerances of two populations of the invasive species New Zealand mud snail Potamopyrgus antipodarum, one population from a high salinity environment in the Columbia River estuary and the other from a fresh water lake. In 1996, New Zealand mud snails were discovered in the tidal reaches of the Columbia River estuary that is routinely exposed to salinity at near full seawater concentrations. In contrast, in their native habitat and throughout its spread in the western US, New Zealand mud snails are found only in fresh water ecosystems. Our aim was to determine whether the Columbia River snails have become salt water adapted. Using a modification of the standard amphipod sediment toxicity test, salinity tolerance was tested using a range of concentrations up to undiluted seawater, and the snails were sampled for mortality at daily time points. Our results show that the Columbia River snails were more tolerant of acute salinity stress with the LC50 values averaging 38 and 22 Practical Salinity Units for the Columbia River and freshwater snails, respectively. DNA sequence analysis and morphological comparisons of individuals representing each population indicate that they were all P. antipodarum. These results suggest that this species is salt water adaptable and in addition, this investigation helps elucidate the potential of this aquatic invasive organism to adapt to adverse environmental conditions.

Hoy, Marshal; Boese, Bruce L.; Taylor, Louise; Reusser, Deborah; Rodriguez, Rusty

2012-01-01

219

Radix auricularia coreana: natural snail host of Clinostomum complanatum in Korea.  

PubMed

An epidemiological survey was carried out to determine the first intermediate host of Clinostomum complanatum among freshwater snails in Korea. Two species of snails belonging to the family Lymnaeidae were collected in Kaum-ji (pond), Uisong-gun, Kyongsangbuk-do. Twelve (0.9%) out of 1,273 Radix auricularia coreana examined were found to liberate cercariae of C. complanatum, which were identified by morphological characteristics and experimental infections in freshwater fish. Pseudorasbora parva. The cercariae were brevifurcate and clinostomatoid. They had a transparent dorsal fin, a well developed penetrating organ and a pair of eye spots. The body measured 119-147 x 33-36 microns, tail stem, 275-370 x 19-26 microns, and furcae, 72-104 microns. Rediae were demonstrated in the infected snail after crushing. Redia, 527-1,630 microns long and 121-368 microns wide, contained 10-45 germ balls and cercariae in various developmental stages. The metacercariae recovered from fish experimentally infected with C. complanatum cercariae were morphologically identical to those from naturally infected fish. PMID:9529857

Chung, D I; Kong, H H; Joo, C Y

1998-03-01

220

Use of black carp (Mylopharyngodon piceus) in biological control of intermediate host snails of fish-borne zoonotic trematodes in nursery ponds in the Red River Delta, Vietnam  

PubMed Central

Background The risks of fish-borne zoonotic trematodes (FZT) to human health constitute an important problem in Vietnam. The infection of humans with these trematodes, such as small liver trematodes (Clonorchis sinensis and Opisthorchis viverrini), intestinal trematodes (Heterophyidae) and others is often thought to be linked to fish culture in areas where the habit of eating raw fish is common. Juvenile fish produced in nurseries are often heavily infected with FZT and since fishes are sold to aquaculture facilities for growth, control of FZT in these fishes should be given priority. Controlling the first intermediate host (i.e., freshwater gastropods), would be an attractive approach, if feasible. The black carp, Mylopharyngodon piceus, is a well-known predator of freshwater snails and is already used successfully for biological control of snails in various parts of the world including Vietnam. Here we report the first trials using it for biological control of intermediate host snails in nursery ponds stocked with 1-week old fry (10–12 mm in length) of Indian carp, Labeo rohita. Methods Semi-field and field experiments were set up to test the effect of black carp on snail populations. In the semi-field experiment a known quantity of snails was initially introduced into a pond which was subsequently stocked with black carp. In the field trial in nursery ponds, density of snails was estimated prior to a nursing cycle and at the end of the cycle (after 9 weeks). Results The results showed that black carp affect the density of snail populations in both semi-field and field conditions. The standing crop of snails in nursery ponds, however, was too high for 2 specimens to greatly reduce snail density within the relatively short nursing cycle. Conclusions We conclude that the black carp can be used in nursery ponds in Northern Vietnam for snail control. Juvenile black carp weighing 100 - 200g should be used because this size primarily prey on intermediate hosts of FZT and other studies have shown that it does not prey on fish fry of other species. It may be necessary to use a high stocking density of black carp or to reduce snail density in the nursery ponds using other measures (e.g. mud removal) prior to stocking fry in order for the black carp to keep the density of intermediate host snails at a very low level. PMID:23680382

2013-01-01

221

Snail modulates cell metabolism in MDCK cells  

SciTech Connect

Highlights: ? MDCK/snail cells were more sensitive to glucose deprivation than MDCK/neo cells. ? MDCK/snail cells had decreased oxidative phosphorylation, O{sub 2} consumption and ATP content. ? TCA cycle enzyme activity, but not expression, was lower in MDCK/snail cells. ? MDCK/snail cells showed reduced PDH activity and increased PDK1 expression. ? MDCK/snail cells showed reduced expression of GLS2 and ACLY. -- Abstract: Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP{sup +}-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of key enzymes. This results in enhanced glucose dependency and leads to cell death under low-glucose conditions. On the other hand, the reduced requirements for oxygen and nutrients from the surrounding environment, might confer the resistance to cell death induced by hypoxia and malnutrition.

Haraguchi, Misako, E-mail: haraguci@m3.kufm.kagoshima-u.ac.jp [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Indo, Hiroko P. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Iwasaki, Yasumasa [Health Care Center, Kochi University, Kochi 780-8520 (Japan)] [Health Care Center, Kochi University, Kochi 780-8520 (Japan); Iwashita, Yoichiro [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Fukushige, Tomoko [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Majima, Hideyuki J. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Izumo, Kimiko; Horiuchi, Masahisa [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Kanekura, Takuro [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Furukawa, Tatsuhiko [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Ozawa, Masayuki [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)

2013-03-22

222

F-LE Snail Invasion  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: In 1966, a Miami boy smuggled three Giant African Land Snails into the country. His grandmother eventually released them into the garden, and in seven ...

2012-05-01

223

Diagnostic of Biomphalaria snails and Schistosoma mansoni: DNA obtained from traces of shell organic materials.  

PubMed

Freshwater snails belonging to the genus Biomphalaria act as intermediate hosts for the parasite trematode Schistosoma mansoni in Africa and in the neotropical region. Identification of such molluscs is carried out based on morphological characters and the presence of cercariae is verified through squeezing snails between two glass slides or by exposing them to artificial light. However, sometimes, the material collected includes molluscs with decomposed bodies or, yet, only empty shells, which precludes their identification and S. mansoni detection. Due to these difficulties, we have developed a methodology in which DNA may be extracted from traces of organic material from inside shells in order to identify molluscs through polymerase chain reaction and restriction fragment length polymorphism and to detect S. mansoni into these snails, by using low stringency polymerase chain reaction. Species-specific profiles obtained from B. glabrata, B. straminea, and B. tenagophila snails and their shells, maintained in laboratory for ten years, showed the same profiles. S. mansoni profiles showed to be present in shell specimens as far as the eighth week after being removed from aquarium. PMID:15543413

Caldeira, Roberta L; Jannotti-Passos, Liana K; Lira, Pollanah M; Carvalho, Omar S

2004-08-01

224

Rapid identification of lymnaeid snails and their infection with Fasciola gigantica in Thailand.  

PubMed

Freshwater snails of the family Lymnaeidae are the intermediate hosts of the liver fluke Fasciola worldwide. While distinct species have been identified at the molecular level in other parts of the world such data have not been published for Thailand. In this study we collected Lymnaeidae from different localities across Thailand and analyzed their 16S rDNA sequences as a molecular signature for classification. In addition to the ubiquitous Radix rubiginosa, we have confirmed the presence of Austropeplea viridis and Radix swinhoei, for the latter of which the ribosomal rDNA sequences are reported for the first time, in North-Thailand. Based on the obtained 16S rDNA data three primer pairs were designed that allowed rapid identification of these snail species by PCR. To determine their infection status, PCR primers for F.gigantica cathepsin L were used in parallel with the snail 16S rDNA species-specific primers in multiplex PCR analyses. Western blot analysis of total snail protein with a monoclonal anti-F.gigantica cathepsin L antibody confirmed positive cathepsin L PCR results. The developed diagnostic PCR will be of use in risk assessment for transmission of fascioliasis in Thailand. PMID:20685274

Kaset, Chollanot; Eursitthichai, Veerachai; Vichasri-Grams, Suksiri; Viyanant, Vithoon; Grams, Rudi

2010-12-01

225

Production of apple snail for space diet  

NASA Astrophysics Data System (ADS)

For food production in space at recycling bio-elements under closed environment, appropriate organisms should be chosen to drive the closed materials recycle loop. We propose a combination of green algae, photosynthetic protozoa, and aquatic plants such as Wolffia spp., for the primary producer fixing solar energy to chemical form in biomass, and apple snail, Pomacea bridgesii, which converts this biomass to animal meat. Because of high proliferation rate of green algae or protozoa compared to higher plants, and direct conversion of them to apple snail, the efficiency of food production in this combination is high, in terms of energy usage, space for rearing, and yield of edible biomass. Furthermore, green algae and apple snail can form a closed ecological system with exchanging bio-elements between two member, i.e. excreta of snail turn to fertilizer of algae, and grown algae become feed for snail. Since apple snail stays in water or on wet substrate, control of rearing is easy to make. Mass production technology of apple snail has been well established to utilize it as human food. Nutrients of apple snail are also listed in the standard tables of food composition in Japan. Nutrients for 100 g of apple snail canned in brine are energy 340 kJ, protein 16.5 g, lipid 1.0 g, cholesterol 240 mg, carbohydrate 0.8 g, Ca 400 mg, Fe 3.9 mg, Zn 1.5 mg. It is rich in minerals, especially Ca and Fe. Vitamin contents are quite low, but K 0.005 mg, B2 0.09 mg, B12 0.0006 mg, folate 0.001 mg, and E 0.6 mg. The amino acid score of apple snail could not be found in literature. Overall, apple snail provides rich protein and animal lipid such as cholesterol. It could be a good source of minerals. However, it does not give enough vitamin D and B12 , which are supposed to be supplemented by animal origin foods. In terms of acceptance in food culture, escargot is a gourmet menu in French dishes, and six to ten snail, roughly 50 g, are served for one person. Apple snail reaches to 30 g of body weight within two or three month from its egg. Several hundreds of egg are laid by one snail. It start egg laying after three months from hatching. In order to harvest 50 g for every day's meal, 3 m2 is required for rearing space. Eating apple snail and establishing its rearing system might save the food crisis on Earth.

Yamashita, Masamichi; Motoki, Shigeru; Space Agriculture Task Force, J.; Katayama, Naomi

226

Mytilus-inhibitory peptide analogues isolated from the ganglia of a pulmonate mollusc, Achatina fulica.  

PubMed

1. Ten peptides that showed an inhibitory effect on phasic contraction of the ABRM of Mytilus were isolated from the ganglia of the African giant snail, Achatina fulica. 2. Seven of the peptides were shown to be hexapeptides having -Pro-Xaa-Phe-Val-NH2 as a common structure, which was previously shown to be a characteristic of Mytilus inhibitory peptides (MIPs). 3. The remaining three were pentadecapeptides, each of which consisted of two MIP-related hexapeptides linked by -Gly-Arg-Arg-. PMID:1354098

Ikeda, T; Yasuda-Kamatani, Y; Minakata, H; Kenny, P T; Nomoto, K; Muneoka, Y

1992-02-01

227

Ecology of Freshwater Fish 2001: 10: 105110 Copyright C Munksgaard 2001 Printed in Denmark All rights reserved  

E-print Network

populations, Lafferty (1993) found that snails ma- tured at a smaller size in populations where the prevalence 1989, 1992). Because fecundity usually increases with fish size (Wootton 1991), individuals allocatingEcology of Freshwater Fish 2001: 10: 105­110 Copyright C Munksgaard 2001 Printed in Denmark ¡ All

Poulin, Robert

228

International Freshwater Agreements  

E-print Network

and the Food and Agriculture Organization of the United Nations. "The World's International Freshwater Variability and Shared Benefits" was authored by Aaron T. Wolf. Transboundary Freshwater Dispute Database Variability and Shared Benefits ................................................... 9 Number of Agreements per

Wolf, Aaron

229

Controlling slugs and snails in orchids  

Technology Transfer Automated Retrieval System (TEKTRAN)

Slugs and snails are pests of orchids, preferring tender plant tissues such as flowers and root tips. Unlike many insect pests which feed only on certain types of plants, most species of slugs and snails are generalists, feeding on green plants, algae, fungi, decaying plant matter, or decaying anima...

230

Inquiry, Land Snails, and Environmental Factors  

ERIC Educational Resources Information Center

Land snails are common invertebrates that fascinate children. Unfortunately, they are seldom used for activities in the science classroom. Snails are inexpensive, take up little space in the classroom, and require only low maintenance, and their learning dividends can be enormous. For example, students can use them in inquiry-based activities that…

Barrow, Lloyd H.; Krantz, Patrick D.

2005-01-01

231

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

PubMed

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

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

2013-12-01

232

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

PubMed Central

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

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

2013-01-01

233

Climate and pH Predict the Potential Range of the Invasive Apple Snail (Pomacea insularum) in the Southeastern United States  

PubMed Central

Predicting the potential range of invasive species is essential for risk assessment, monitoring, and management, and it can also inform us about a species’ overall potential invasiveness. However, modeling the distribution of invasive species that have not reached their equilibrium distribution can be problematic for many predictive approaches. We apply the modeling approach of maximum entropy (MaxEnt) that is effective with incomplete, presence-only datasets to predict the distribution of the invasive island apple snail, Pomacea insularum. This freshwater snail is native to South America and has been spreading in the USA over the last decade from its initial introductions in Texas and Florida. It has now been documented throughout eight southeastern states. The snail’s extensive consumption of aquatic vegetation and ability to accumulate and transmit algal toxins through the food web heighten concerns about its spread. Our model shows that under current climate conditions the snail should remain mostly confined to the coastal plain of the southeastern USA where it is limited by minimum temperature in the coldest month and precipitation in the warmest quarter. Furthermore, low pH waters (pH <5.5) are detrimental to the snail’s survival and persistence. Of particular note are low-pH blackwater swamps, especially Okefenokee Swamp in southern Georgia (with a pH below 4 in many areas), which are predicted to preclude the snail’s establishment even though many of these areas are well matched climatically. Our results elucidate the factors that affect the regional distribution of P. insularum, while simultaneously presenting a spatial basis for the prediction of its future spread. Furthermore, the model for this species exemplifies that combining climatic and habitat variables is a powerful way to model distributions of invasive species. PMID:23451090

Byers, James E.; McDowell, William G.; Dodd, Shelley R.; Haynie, Rebecca S.; Pintor, Lauren M.; Wilde, Susan B.

2013-01-01

234

The Complete Mitochondrial Genome of Galba pervia (Gastropoda: Mollusca), an Intermediate Host Snail of Fasciola spp  

PubMed Central

Complete mitochondrial (mt) genomes and the gene rearrangements are increasingly used as molecular markers for investigating phylogenetic relationships. Contributing to the complete mt genomes of Gastropoda, especially Pulmonata, we determined the mt genome of the freshwater snail Galba pervia, which is an important intermediate host for Fasciola spp. in China. The complete mt genome of G. pervia is 13,768 bp in length. Its genome is circular, and consists of 37 genes, including 13 genes for proteins, 2 genes for rRNA, 22 genes for tRNA. The mt gene order of G. pervia showed novel arrangement (tRNA-His, tRNA-Gly and tRNA-Tyr change positions and directions) when compared with mt genomes of Pulmonata species sequenced to date, indicating divergence among different species within the Pulmonata. A total of 3655 amino acids were deduced to encode 13 protein genes. The most frequently used amino acid is Leu (15.05%), followed by Phe (11.24%), Ser (10.76%) and IIe (8.346%). Phylogenetic analyses using the concatenated amino acid sequences of the 13 protein-coding genes, with three different computational algorithms (maximum parsimony, maximum likelihood and Bayesian analysis), all revealed that the families Lymnaeidae and Planorbidae are closely related two snail families, consistent with previous classifications based on morphological and molecular studies. The complete mt genome sequence of G. pervia showed a novel gene arrangement and it represents the first sequenced high quality mt genome of the family Lymnaeidae. These novel mtDNA data provide additional genetic markers for studying the epidemiology, population genetics and phylogeographics of freshwater snails, as well as for understanding interplay between the intermediate snail hosts and the intra-mollusca stages of Fasciola spp.. PMID:22844544

Huang, Wei-Yi; Zhao, Guang-Hui; Wei, Shu-Jun; Song, Hui-Qun; Xu, Min-Jun; Lin, Rui-Qing; Zhou, Dong-Hui; Zhu, Xing-Quan

2012-01-01

235

Freshwater molluscs as indicators of bioavailability and toxicity of metals in surface-water systems  

SciTech Connect

Freshwater molluscs--snails and bivalves--have been used frequently as bioindicator organisms. With increasing needs for research on contaminant effects in freshwater ecosystems, this kind of biomonitoring is likely to develop further in the future. Molluscs can be used effectively for studies of both organic and inorganic contaminants; this review focuses on studies involving bioaccumulation and toxicity of metals. Two important advantages of snails and bivalves over most other freshwater organisms for biomonitoring research are their large size and limited mobility. In addition, they are abundant in many types of freshwater environments and are relatively easy to collect and identify. At metal concentrations that are within ranges common to natural waters, they are generally effective bioaccumulators of metals. Biomonitoring studies with freshwater molluscs have covered a wide diversity of species, metals, and environments. The principal generalization that can be drawn from this research is that bioaccumulation and toxicity are extremely situation dependent; hence, it is difficult to extrapolate results from any particular study to other situations where the biological species or environmental conditions are different. Even within one species, individual characteristics such as size, life stage, sex, and genotype can have significant effects on responses to contaminants. The bioavailability of the metal is highly variable and depends on pH, presence of organic ligands, water hardness, and numerous other controlling factors. Despite this variability, past studies provide some general principles that can facilitate planning of research with freshwater snails and bivalves as metal bioindicators. These principles may also be useful in understanding and managing freshwater ecosystems.

Elder, J.F.; Collins, J.J. (U.S. Geological Survey, Madison, WI (United States))

1991-01-01

236

Environmental calcium modifies induced defences in snails.  

PubMed Central

Inducible defences are adaptive phenotypes that arise in response to predation threats. Such plasticity incurs costs to individuals, but there has been little interest in how such induced traits in animals may be constrained by environmental factors. Here, we demonstrate that calcium availability interacts with predation cues to modify snail shell growth and form. Small snails increased their growth and were heavier when exposed to fish chemical cues, but this response was calcium limited. There was also an interactive effect of fish cues and calcium on the shell growth of larger snails, but shell strength and aperture narrowness were affected by calcium alone. For small snails, behavioural avoidance was greatest for snails exhibiting least morphological plasticity, suggesting a trade-off. There was no trade-off of somatic growth with plasticity. We suggest that the expression of defensive traits in molluscs can be constrained by calcium availability, which has implications for molluscan ecology and evolution. PMID:15101422

Rundle, Simon D; Spicer, John I; Coleman, Ross A; Vosper, Jo; Soane, Julie

2004-01-01

237

Aquatic Toxicology 150 (2014) 3644 Contents lists available at ScienceDirect  

E-print Network

, Lymnaea stagnalis, is the most sensitive aquatic organism tested to date for Ni. We undertook a series, ion homeostasis, acid-base balance, and nickel uptake in the freshwater pulmonate snail, Lymnaea stagnalis Som Niyogia, , Kevin V. Brixb , Martin Grosellc a Department of Biology, University

Grosell, Martin

238

De Novo Transcriptome Analysis of Oncomelania hupensis after Molluscicide Treatment by Next-Generation Sequencing: Implications for Biology and Future Snail Interventions  

PubMed Central

The freshwater snail Oncomelania hupensis is the only intermediate host of Schistosoma japonicum, which causes schistosomiasis. This disease is endemic in the Far East, especially in mainland China. Because niclosamide is the only molluscicide recommended by the World Health Organization, 50% wettable powder of niclosamide ethanolamine salt (WPN), the only chemical molluscicide available in China, has been widely used as the main snail control method for over two decades. Recently, a novel molluscicide derived from niclosamide, the salt of quinoid-2',5-dichloro-4'-nitro-salicylanilide (Liu Dai Shui Yang An, LDS), has been developed and proven to have the same molluscicidal effect as WPN, with lower cost and significantly lower toxicity to fish than WPN. The mechanism by which these molluscicides cause snail death is not known. Here, we report the next-generation transcriptome sequencing of O. hupensis; 145,008,667 clean reads were generated and assembled into 254,286 unigenes. Using GO and KEGG databases, 14,860 unigenes were assigned GO annotations and 4,686 unigenes were mapped to 250 KEGG pathways. Many sequences involved in key processes associated with biological regulation and innate immunity have been identified. After the snails were exposed to LDS and WPN, 254 unigenes showed significant differential expression. These genes were shown to be involved in cell structure defects and the inhibition of neurohumoral transmission and energy metabolism, which may cause snail death. Gene expression patterns differed after exposure to LDS and WPN, and these differences must be elucidated by the identification and annotation of these unknown unigenes. We believe that this first large-scale transcriptome dataset for O. hupensis will provide an opportunity for the in-depth analysis of this biomedically important freshwater snail at the molecular level and accelerate studies of the O. hupensis genome. The data elucidating the molluscicidal mechanism will be of great benefit in future snail control efforts. PMID:25775015

Zhao, Qin Ping; Xiong, Tao; Xu, Xing Jian; Jiang, Ming Sen; Dong, Hui Fen

2015-01-01

239

De Novo Transcriptome Analysis of Oncomelania hupensis after Molluscicide Treatment by Next-Generation Sequencing: Implications for Biology and Future Snail Interventions.  

PubMed

The freshwater snail Oncomelania hupensis is the only intermediate host of Schistosoma japonicum, which causes schistosomiasis. This disease is endemic in the Far East, especially in mainland China. Because niclosamide is the only molluscicide recommended by the World Health Organization, 50% wettable powder of niclosamide ethanolamine salt (WPN), the only chemical molluscicide available in China, has been widely used as the main snail control method for over two decades. Recently, a novel molluscicide derived from niclosamide, the salt of quinoid-2',5-dichloro-4'-nitro-salicylanilide (Liu Dai Shui Yang An, LDS), has been developed and proven to have the same molluscicidal effect as WPN, with lower cost and significantly lower toxicity to fish than WPN. The mechanism by which these molluscicides cause snail death is not known. Here, we report the next-generation transcriptome sequencing of O. hupensis; 145,008,667 clean reads were generated and assembled into 254,286 unigenes. Using GO and KEGG databases, 14,860 unigenes were assigned GO annotations and 4,686 unigenes were mapped to 250 KEGG pathways. Many sequences involved in key processes associated with biological regulation and innate immunity have been identified. After the snails were exposed to LDS and WPN, 254 unigenes showed significant differential expression. These genes were shown to be involved in cell structure defects and the inhibition of neurohumoral transmission and energy metabolism, which may cause snail death. Gene expression patterns differed after exposure to LDS and WPN, and these differences must be elucidated by the identification and annotation of these unknown unigenes. We believe that this first large-scale transcriptome dataset for O. hupensis will provide an opportunity for the in-depth analysis of this biomedically important freshwater snail at the molecular level and accelerate studies of the O. hupensis genome. The data elucidating the molluscicidal mechanism will be of great benefit in future snail control efforts. PMID:25775015

Zhao, Qin Ping; Xiong, Tao; Xu, Xing Jian; Jiang, Ming Sen; Dong, Hui Fen

2015-01-01

240

Accumulation and distributions of 137Cs in fresh water snail Pila ampullacea  

NASA Astrophysics Data System (ADS)

Pila ampullacea are found in tropical freshwaters of Indonesia. This snail exhibit several characteristics of ideal indicator organisms in order to understand the bioaccumulation of 137Cs . Biokinetic experiment was performaced in aquaria system and under influenced of concentration K+ in water. The result of experiment shown that Under difference K+ concentration in water, Pila ampullacea have capability to accumulated 137Cs with CF value range 8.95 to 12.52 ml.g-1. Both uptake and depuration rate were influenced by concentration of K+ in water.

Suseno, Heny

2014-10-01

241

Accumulation and distributions of {sup 137}Cs in fresh water snail Pila ampullacea  

SciTech Connect

Pila ampullacea are found in tropical freshwaters of Indonesia. This snail exhibit several characteristics of ideal indicator organisms in order to understand the bioaccumulation of {sup 137}Cs. Biokinetic experiment was performaced in aquaria system and under influenced of concentration K{sup +} in water. The result of experiment shown that Under difference K{sup +} concentration in water, Pila ampullacea have capability to accumulated {sup 137}Cs with CF value range 8.95 to 12.52 ml.g{sup ?1}. Both uptake and depuration rate were influenced by concentration of K{sup +} in water.

Suseno, Heny, E-mail: henis@batan.go.id [Marine Radioecology Group, Center for Radiation Safety Technology and Metrology - National Nuclear Energy Agency, Jl. Lebak Bulus Raya No. 49, Kotak Pos 7043 JKSKL Jakarta Selatan 12070 (Indonesia)

2014-10-24

242

Host specificity of Austropeplea ollula (Gastropoda: Lymnaeidae) to miracidial infection with a human intestinal fluke Neodiplostomum seoulense (Trematoda: Diplostomatidae) in Korea.  

PubMed

Three species of freshwater pulmonate snails of Lymnaeidae have been reported from Korea, Radix auricularia coreana, Austropeplea ollula, and Fossaria truncatula. Of these 3 species, only A. ollula was naturally infected with Neodiplostomum seoulense cercariae (prevalence, 0.3%). In experiments with the laboratory-reared snails, A. ollula was found to be susceptible to the N. seoulense miracidia (prevalence, 10%). This is the first report of A. ollula as the first molluscan intermediate host for N. seoulense in Korea. PMID:12099442

Chung, P R; Jung, Y; Park, Y K; Hwang, M G

2002-06-01

243

Seasonal changes in the biochemical composition of the chiton Chiton iatricus (Polyplacophora: Mollusca) and the marine pulmonate Onchidium verruculatum (Gastropoda: Mollusca) in relation to their reproductive cycles  

Microsoft Academic Search

Seasonal changes in the biochemical composition of two molluses, gonochoric Chiton iatricus and a marine pulmonate, Ochnidium verruculatum inhabiting the same tropical area, but having different modes of reproduction, were studied. Protein is the major biochemical component stored in C. iatricus, whereas lipid is predominantly stored in O. verruculatum. The correlation between these quantifications and the annual reproductive cycles of

U. D. Deshpande; R. Nagabhushanam

1983-01-01

244

Haemolymph Components of Infected & None Infected Lymnaea snails with Xiphidiocercariae  

PubMed Central

Background In this study the haemolymph components of infected and none infected Lymnaea gedrosiana with xiphidiocercaria larvae was compared. Methods Five hundred Fifty Lymnaea snails were collected from Ilam and Mazandaran provinces, Iran, during 2008–2009. The snails were transported to the lab at Tehran University of Medical Sciences and their cercarial sheddings were studied. Haemolmyphs of snails were extracted and cells were counted using haemocytometer and cell-surface carbohydrate were recognized by conjugated lectin (Lentil). Haemolymph protein concentrations were measured by Bradford protein assay method and soluble protein compositions were determined on sodium dodecyl sulphate polyacrilamide gel electrophoresis (SDS-PAGE). Results From the 550 examined Lymnaea snails for cercariae, 27 snails were infected with xiphidiocercariae. Mean of haemolymph cells (haemocyte) number were obtained 93480±2.43 (cells/ml) for none infected snails (25 snail) and 124560±2800 (cells/ml) for infected snails (25 snail). Mannose carbohydrate was recognized on haemocyte of none infected and infected snails. Mean of protein concentration of haemolymph plasma was obtained as 1354±160 µg/ml (1.4 mg/ml) for none infected snails (25 snails) and 1802±138 µg/ml (1.8 mg/ml) for infected snail (25 snails). Comparing to none infected snails, the SDS-PAGE results of haemolymph plasma of infected snails, showed an extra protein band (70 kDa). The results showed a significant difference between the amounts and the kinds of proteins in haemolymph of infected and none infected snails. Conclusion This information might be useful to understand of parasite detection, adhesion, engulfment and antigen agglutination by snail. PMID:22347279

Saboor Yaraghi, AA; Farahnak, A; Eshraghian, MR

2011-01-01

245

Schistosomes and snails: a molecular encounter  

PubMed Central

Biomphalaria glabrata snails play an integral role in the transmission of Schistosoma mansoni, the causative agent for human schistosomiasis in the Western hemisphere. For the past two decades, tremendous advances have been made in research aimed at elucidating the molecular basis of the snail/parasite interaction. The growing concern that there is no vaccine to prevent schistosomiasis and only one effective drug in existence provides the impetus to develop new control strategies based on eliminating schistosomes at the snail-stage of the life cycle. To elucidate why a given snail is not always compatible to each and every schistosome it encounters, B. glabrata that are either resistant or susceptible to a given strain of S. mansoni have been employed to track molecular mechanisms governing the snail/schistosome relationship. With such snails, genetic markers for resistance and susceptibility were identified. Additionally, differential gene expression studies have led to the identification of genes that underlie these phenotypes. Lately, the role of schistosomes in mediating non-random relocation of gene loci has been identified for the first time, making B. glabrata a model organism where chromatin regulation by changes in nuclear architecture, known as spatial epigenetics, orchestrated by a major human parasite can now be investigated. This review will highlight the progress that has been made in using molecular approaches to describe snail/schistosome compatibility issues. Uncovering the signaling networks triggered by schistosomes that provide the impulse to turn genes on and off in the snail host, thereby controlling the outcome of infection, could also yield new insights into anti-parasite mechanism(s) that operate in the human host as well. PMID:25101114

Knight, Matty; Arican-Goktas, Halime D.; Ittiprasert, Wannaporn; Odoemelam, Edwin C.; Miller, André N.; Bridger, Joanna M.

2014-01-01

246

Introduction, distribution, spread, and impacts of exotic freshwater gastropods in Texas  

Microsoft Academic Search

We examined the patterns of distribution, vectors of introduction, and potential ecological impacts of freshwater exotic species\\u000a in Texas over the last 45 years. Currently, five species of exotic gastropods are established: channeled-type applesnail (Pomacea insularum), red-rim melania (Melanoides tuberculatus), quilted melania (Tarebia granifera), giant rams-horn snail (Marisa cornuarietis), and Chinese mysterysnail (Cipangopaludina\\u000a chinensis). In contrast to the northern part of

Alexander Y. Karatayev; Lyubov E. Burlakova; Vadim A. Karatayev; Dianna K. Padilla

2009-01-01

247

Snail destabilizes cell surface Crumbs3a.  

PubMed

During epithelial to mesenchymal transition (EMT), cells modulate expression of proteins resulting in loss of apical-basal polarity. Effectors of this EMT switch target the polarity protein Crumbs3a, a small transmembrane protein that is essential for generation of the apical membrane and tight junctions of mammalian epithelial cells. We previously showed that the Crumbs3 gene is a direct target of transcriptional regulation by Snail, a potent inducer of EMT. However, Snail has also been shown to have multiple non-transcriptional roles, including regulation of cell adhesion, proliferation and survival. Using SNAP-tag labeling, we determined that cell surface Crumbs3a has a half-life of approximately 3?h and that this cell surface half-life is significantly reduced when EMT is induced by Snail. We further observe that Snail induces differential glycosylation of Crumbs3a, including sialylation, suggesting a mechanism by which Crumbs3a may be destabilized. These results indicate that Crumbs3a is a post-translational target of Snail, in addition to being a transcriptional target. We conclude that Snail's ability to post-translationally modify and destabilize Crumbs3a augments the depolarizing process of EMT. PMID:22554228

Harder, Jennifer L; Whiteman, Eileen L; Pieczynski, Jay N; Liu, Chia-Jen; Margolis, Ben

2012-08-01

248

The role of Snail in prostate cancer  

PubMed Central

Prostate cancer is the second most frequently diagnosed cancer and the sixth leading cause of death from cancer in men. Epithelial-mesenchymal transition (EMT) is a process by which cancer cells invade and migrate, and is characterized by loss of cell-cell adhesion molecules such as E-cadherin and increased expression of mesenchymal proteins such as vimentin; EMT is also associated with resistance to therapy. Snail, a master regulator of EMT, has been extensively studied and reported in cancers such as breast and colon; however, its role in prostate cancer is not as widely reported. The purpose of this review is to put together recent facts that summarize Snail signaling in human prostate cancer. Snail is overexpressed in prostate cancer and its expression and activity is controlled via phosphorylation and growth factor signaling. Snail is involved in its canonical role of inducing EMT in prostate cancer cells; however, it plays a role in non-canonical pathways that do not involve EMT such regulation of bone turnover and neuroendocrine differentiation. Thus, studies indicate that Snail signaling contributes to prostate cancer progression and metastasis and therapeutic targeting of Snail in prostate cancer holds promise in ?future. PMID:23076049

Smith, Bethany N.; Odero-Marah, Valerie A.

2012-01-01

249

Identification and characterization of a goose-type lysozyme from sewage snail Physa acuta.  

PubMed

Freshwater snail Physa acuta has been considered as an important invasive species and medical mollusc. Field investigation has shown that this snail could survive better than other snails in polluted water bodies. To understand the immune mechanisms of P. acuta, suppression subtractive hybridization hepatopancreas cDNA library has been constructed with bacterial challenge. In this study, a full-length cDNA of a novel goose-type lysozyme (PALysG) has been identified from P. acuta by EST and RACE technique. The conservative structure domains share high homology with other molluscan g-type lysozymes including the SLT domain, the substrate binding sites, the catalytic residues, three alpha-helices structures and six molluscan specific cysteines. Meanwhile, PALysG is the first record of goose-type lysozyme in Gastropoda. Real-time PCR indicated that PALysG mRNA had been expressed significantly at high levels in hepatopancreas for 8-48 h. PALysG recombinant protein displayed the lytic activity of g-type lysozyme with other organisms against Micrococcus lysodikicus. PMID:24882016

Guo, Yunhai; He, Hongxuan

2014-08-01

250

The Apple Snail Pomacea canaliculata, a Novel Vector of the Rat Lungworm, Angiostrongylus cantonensis: its Introduction, Spread, and Control in China  

PubMed Central

The freshwater apple snail Pomacea canaliculata was introduced to Taiwan then to mainland China in the early 1980s from Argentina, its native region, for the purpose of aquaculture. Because of the lack of natural enemies and its tolerance of a wide range of environmental conditions, both its abundance and distribution have dramatically increased and it has become a harmful species to local agriculture and other native species in many areas of China. Unfortunately, the snail also acts as an intermediate host of Angiostrongylus cantonensis, and has been implicated in transfer of the parasite to people, resulting in angiostrongyliasis manifested as eosinophilic meningitis. Efforts to prevent its further spread and population expansion were initiated many years ago, including the use of chemicals and biological control agents to control the snail. PMID:23901377

Wu, Zhong-Dao; Lun, Zhao-Rong

2013-01-01

251

The apple snail Pomacea canaliculata, a novel vector of the rat lungworm, Angiostrongylus cantonensis: its introduction, spread, and control in China.  

PubMed

The freshwater apple snail Pomacea canaliculata was introduced to Taiwan then to mainland China in the early 1980s from Argentina, its native region, for the purpose of aquaculture. Because of the lack of natural enemies and its tolerance of a wide range of environmental conditions, both its abundance and distribution have dramatically increased and it has become a harmful species to local agriculture and other native species in many areas of China. Unfortunately, the snail also acts as an intermediate host of Angiostrongylus cantonensis, and has been implicated in transfer of the parasite to people, resulting in angiostrongyliasis manifested as eosinophilic meningitis. Efforts to prevent its further spread and population expansion were initiated many years ago, including the use of chemicals and biological control agents to control the snail. PMID:23901377

Yang, Ting-Bao; Wu, Zhong-Dao; Lun, Zhao-Rong

2013-06-01

252

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

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

Yadav, Ram P.; Singh, Ajay

2014-01-01

253

Giant multimodal heart motoneurons of Achatina fulica: a new cardioregulatory input in pulmonates.  

PubMed

The regulation of the heartbeat by the two largest neurons, d-VLN and d-RPLN, on the dorsal surface of visceral and right parietal ganglia of Giant African snail, Achatina fulica, was examined. Using the new method of animal preparation, for the first time, discrete biphasic inhibitory-excitatory junction potentials (I-EJPs) in the heart and several muscles of the visceral sac were recorded. The duration of hyperpolarizing phase (H-phase) of biphasic I-EJPs was 269+/-5.6 ms (n=5), which is 2-3 times less than that of the cholinergic inhibitory JPs (682+/-68.5 ms, n=5). The H-phase of I-EJPs was not altered by the application of atropine, picrotoxine, succinylcholinchloride, D-tubocurarine and tetraethylammonium or substitution of Cl(-) ions. Even the low-frequency neuronal discharges (1-2 imp/s) evoked significant facilitation and potentiation of the H-phase. Between the multimodal neurons d-VLN/d-RPLN and mantle or visceral organs there is evidence of direct synaptic connections. These neurons were found to have no axonal branches in the intestinal nerve as once suspected but reach the heart through several other nerves. New giant heart motoneurons do not interact with previously identified cardioregulatory neurons. PMID:11672694

Zhuravlev, V; Bugaj, V; Kodirov, S; Safonova, T; Staruschenko, A

2001-08-01

254

Decreased trophic position as a function of increasing body size of a benthic omnivorous fish from the largest freshwater lake in China  

Microsoft Academic Search

Potential body size-trophic position relationships of the Darkbarbel catfish Pelteobagrus vachelli (Richardson 1846) were examined using stable isotope analysis. Pelteobagrus vachelli is a benthic feeding fish from Lake Poyang, the largest freshwater lake in China. Two-source mixing model with mussel (Corbicula fluminea) and snail (Bellamya aeruginosa) as baseline primary consumers of planktonic and benthic food webs, respectively, was used to

Yuyu Wang; Xiubo Yu; Jun Xu

2011-01-01

255

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

PubMed

Endocrine disruptors are known to alter endogenous free and esterified levels of androgenic and estrogenic steroid hormones in aquatic mollusks. The origin of steroids in these animals, however, remains controversial. In the present study, free and esterified testosterone concentrations were measured in the hermaphroditic aquatic gastropod Lymnaea stagnalis exposed to molecules known for their androgenic (testosterone and tributyltin), anti-androgenic (cyproterone-acetate), and estrogenic (chlordecone) properties, by reference to their mode of action in vertebrates. In parallel, snail oviposition and fecundity were followed over a 21-d exposure period. Testosterone exposure resulted in increased esterified testosterone levels, whereas free testosterone concentrations remained stable. In contrast, cyproterone-acetate significantly increased the free form of testosterone with no changes in the esterified form, whereas chlordecone showed a tendency to reduce (though not significantly) esterified testosterone concentrations without changing free testosterone levels. Finally, tributyltin did not alter testosterone homeostasis. The production of egg clutches and eggs was significantly reduced only in the snails exposed to the highest concentrations of chlordecone (19.6?µg/L) and tributyltin (94.2?ng Sn/L). Overall, the present study demonstrates that uptake of testosterone from the exposure medium occurs in L. stagnalis. Moreover, it shows that cyproterone-acetate and, to a lesser extent, chlordecone can alter endogenous testosterone levels in this freshwater snail. However, the relationship between hormonal changes and snail reproduction has not been established. Environ Toxicol Chem 2013;32:1740-1745. © 2013 SETAC. PMID:23564527

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

2013-08-01

256

Is reproduction of the snail Physella acuta affected by endocrine disrupting compounds? An in situ bioassay in three Iberian basins.  

PubMed

An in situ bioassay was conducted in three Iberian basins (Ebro, Llobregat and Júcar Rivers) to study the reproductive effects on the freshwater snail Physella acuta. Adult individuals were transplanted in specially designed cylindrical cages. Endpoints included mortality, number of eggs and clutches, number of eggs per clutch and embryo development after 8 days. The results were contrasted with laboratory controls. Significant changes in P. acuta reproduction parameters were detected in all of the rivers: the number of clutches or eggs per snail decreased in the Ebro and Llobregat basins downstream but the number of eggs per clutch increased. The complete development of snails was delayed at some sites downstream in the Júcar and the Ebro basins. The results were contrasted with concentrations of Endocrine Disrupting Compounds (EDCs) and their Estrogenic Equivalent Quotients (EEQs). Positive relationships (Pearson correlations) were identified between the number of eggs per clutch and the total EDC concentration, bisphenol A (BPA) and their EEQs, lipid regulators and diuretics. These endocrine-disrupting chemicals may constitute a toxicological risk for the reproductive performance of snails in the studied basins. PMID:23972665

De Castro-Català, N; López-Doval, J; Gorga, M; Petrovic, M; Muñoz, I

2013-12-15

257

Exposure of the snail Potamopyrgus antipodarum to herbicide boosts output and survival of parasite infective stages?  

PubMed Central

Anthropogenic stressors such as pollutants can modulate levels of parasitic infections in aquatic animals by suppressing host immunity or through some other mechanisms. One such mechanism could involve increases in either the quantity or quality of infective stages produced by parasites. We investigated the effect of exposure of infected snails, Potamopyrgus antipodarum, to different concentrations of the widely-used herbicide glyphosate, on (i) the production of infective cercariae by three trematode species, Coitocaecum parvum, Apatemon sp. and an undescribed renicolid, and (ii) the survival of cercariae of the latter species. For all three trematode species, infected snails exposed over a month to low (0.36 mg a.i. L?1) or medium (3.6 mg a.i. L?1) formulated glyphosate concentrations released between 1.5 and 3 times more cercariae per day than snails under control conditions. The similar pattern seen in all trematodes suggests a general weakening of the host benefiting any of its parasites rather than some parasite species-specific mechanism. In addition, the survival of renicolid cercariae improved with increasing glyphosate concentrations, with cercariae living about 50% longer in the medium concentration (3.6 mg a.i. L?1) than in control conditions. Our results demonstrate a clear interaction between glyphosate pollution and parasitism by trematodes in freshwater systems, occurring at glyphosate concentrations recorded in aquatic habitats, and within the environmental exposure limit allowed in New Zealand freshwaters. Future risk assessments and toxicity tests need to consider indirect impacts resulting from infections to invertebrate and vertebrate species penetrated by cercariae and serving as second intermediate hosts of trematodes. PMID:24533309

Hock, Sabrina D.; Poulin, Robert

2012-01-01

258

Comparison of long-term postoperative sequelae in patients with tetralogy of Fallot versus isolated pulmonic stenosis.  

PubMed

Patients with tetralogy of Fallot (TOF) after complete repair and pulmonic stenosis (PS) after surgical valvotomy often develop significant pulmonic regurgitation (PR) that eventually requires valve replacement. Although criteria exist for the timing of pulmonary valve replacement in TOF, it remains less clear when to intervene in valvotomy patients and whether TOF recommendations can be applied. Our aim was to compare the structural and functional sequelae of valvotomy for PS with complete repair for TOF. We compared the clinical characteristics, electrocardiograms, echocardiograms, cardiac magnetic resonance imaging (MRI), and invasive hemodynamics of 109 adults (34 PS and 75 TOF) newly referred to a congenital heart disease center for evaluation of PR between 2005 and 2012. Both cohorts were similar in terms of baseline demographics and presenting New York Heart Association function class. Valvotomy patients had a slightly greater degree of PR by echocardiogram, although it was similar by cardiac MRI. Electrocardiography QRS width was greater in patients with TOF (114±27 vs 150±28 ms, p<0.001). MRI right ventricular ejection fraction (49±8 vs 41±11%, p=0.001) and left ventricular ejection fraction (59±7 vs 52±10%, p=0.002) were lower in patients with TOF. Pacemaker or defibrillator implantation was significantly greater in patients with TOF (3% vs 23%, p=0.011). In conclusion, patients postvalvotomy and complete repair present with similar degrees of PR and severity of symptoms. Biventricular systolic function and electrocardiography QRS width appear less affected, suggesting morphologic changes in TOF and its repair that extend beyond the effects of PR. These findings suggest the need for developing disease-specific guidelines for patients with PR postvalvotomy. PMID:24878128

Zdradzinski, Michael J; Qureshi, Athar M; Stewart, Robert; Pettersson, Gosta; Krasuski, Richard A

2014-07-15

259

DISPERSAL IN FRESHWATER INVERTEBRATES  

Microsoft Academic Search

? Abstract Movement between discrete habitat patches can present significant challenges to organisms. Freshwater invertebrates achieve dispersal using a variety of mechanisms that can be broadly categorized as active or passive, and which have important consequences for processes of colonization, gene flow, and evolutionary divergence. Apart from flight in adult freshwater insects, active dispersal appears rela- tively uncommon. Passive dispersal

David T. Bilton; Joanna R. Freeland; Beth Okamura

2001-01-01

260

Rapid upregulation of heart antioxidant enzymes during arousal from estivation in the Giant African snail (Achatina fulica).  

PubMed

Estivation is an adaptive response to environments characterized by elevated temperatures and desiccative stress, as may occur during summer dry seasons. Similar to diapause and hibernation, it is characterized by low levels of activity, a drastically suppressed metabolic rate and enhanced stress resistance. We tested the hypothesis that Achatina fulica, a pulmonate land snail, enhances stress resistance during estivation and/or arousal by upregulating intracellular antioxidant defenses in the heart, kidney, hepatopancreas and foot tissues. No statistically significant changes in mitochondrial or cytosolic superoxide dismutase levels or activities, or glutathione peroxidase, glutathione reductase or catalase activities were associated with estivation in any tissue, however. In contrast, during arousal from estivation, activities of several antioxidant enzymes increased in heart, hepatopancreas and foot. In heart, a rapid increase in MnSOD protein levels was observed that peaked at 2h post arousal, but no such change was observed in CuZnSOD protein levels. Glutathione peroxidase activity was upregulated at 1h post arousal and remained elevated until 8h post arousal in heart tissue. Glutathione peroxidase was also upregulated at 24h post arousal in foot tissue. Glutathione reductase activity was upregulated at 4h post arousal in heart and foot tissues whereas catalase activity showed no changes. Markers of lipid peroxidation and protein damage revealed no significant increases during estivation or arousal. Therefore, antioxidant enzymes may play a role in oxidative stress defense specifically during arousal from estivation in A. fulica. PMID:20621194

Salway, Kurtis D; Tattersall, Glenn J; Stuart, Jeffrey A

2010-11-01

261

Octopamine boosts snail locomotion: behavioural and cellular analysis  

Microsoft Academic Search

We measured the reduction in locomotion of unrestrained pond snails, Lymnaea stagnalis, subsequent to transdermal application of two selective octopamine antagonists, epinastine and phentolamine. After 3 h in fresh standard snail water following treatment with 4 mM epinastine or 3.5 mM phentolamine, the snails’ speed was reduced to 25 and 56% of the controls (P P = 0.02, respectively). The snails’ speed decreased as the drug

Jennifer C. Ormshaw; Christopher J. H. Elliott

2006-01-01

262

Snail populations in arctic lakes: competition mediated by predation?  

Microsoft Academic Search

For 2 species of snails in arctic Alaskan lakes, I studied the patterns of snail distribution with respect to habitat, distribution of predatory fish, and the potential for interspecific competition. The snails Lymnaea elodes and Valvata lewisi co-exist in these arctic lakes, either in the presence of lake trout, Salvelinus namaycush, or in the absence of predation. Intensive sediment core

Anne E. Hershey

1990-01-01

263

Substratum heterogeneity, crypsis, and colourpolymorphism in an intertidal snail (Littorinamariue)  

E-print Network

Substratum heterogeneity, crypsis, and colourpolymorphism in an intertidal snail (Littorinamariue. Substratum heterogeneity, crypsis, and colour polymorphism in an intertidal snail (Liltorina mariae).Can. J, crypsis, and colour polymorphism in an intertidal snail (Littorina mariae). Can. J . Zool. 57: 1070- 1085

Reimchen, Thomas E.

264

Images of Minute Minnesota Land Snails Matt Barthel  

E-print Network

Images of Minute Minnesota Land Snails Matt Barthel January 2000 This disk contains diagnostic images representative of minute land snail taxa from Minnesota. The snails imaged are from throughout at the University of Wisconsin-Green Bay (UWGB). The shells imaged were assigned to species (or subspecies) based

Nekola, Jeffrey C.

265

Epigenetic Regulation of EMT: The Snail Story  

PubMed Central

While the epithelial-mesenchymal transition (EMT) plays a fundamental role during development, its deregulation can adversely promote tumor metastasis. The phenotypic and cellular plasticity of EMT indicates that it is subject to epigenetic regulation. In this review, we try to embrace recent findings on the mechanisms of the transcription factor Snail-mediated E-cadherin silencing, which is a hallmark of EMT. Our studies as well as those of others have clearly demonstrated that Snail can recruit multiple chromatin enzymes including LSD1, HDAC1/2, PRC2, G9a and Suv39H1 to the E-cadherin promoter. These enzymes function in a highly orchestrated fashion to generate heterochromatin and promote DNA methyltransferase (DNMT)-mediated DNA methylation at the promoter region. Disruption of the connection between Snail and these chromatin-modifying enzymes may represent an efficient strategy for the treatment of EMT-related diseases. PMID:23888971

Lin, Yiwei; Dong, Chenfang; Zhou, Binhua P.

2014-01-01

266

The Dual Protection of a Micro Land Snail against a Micro Predatory Snail  

PubMed Central

Defense against a single predatory attack strategy may best be achieved not by a single trait but by a combination of different traits. We tested this hypothesis experimentally by examining the unique shell traits (the protruded aperture and the denticles within the aperture) of the micro land snail Bensonella plicidens. We artificially altered shell characteristics by removing the denticles and/or cutting the protruded aperture. These snails were offered to the carnivorous micro land snail Indoennea bicolor, which preys on the snails by gaining entry to their shell. B. plicidens exhibited the best defence when both of the traits studied were present; the defensive ability of B. plicidens decreased if either trait was removed and was further reduced if both traits were removed. These results suggest that a combination of different traits provides more effective defence against attack by the predator than either single trait by itself. PMID:23326582

Wada, Shinichiro; Chiba, Satoshi

2013-01-01

267

Biological invasions: the case of planorbid snails  

Microsoft Academic Search

A large number of planorbid snails are now commonly transported by man mainly through the aquatic plant trade. However, only a restricted number of species establish viable populations in a new habitat and a more restricted number spread. Only five planorbid species can be ranked in this last category and can be considered as pests because of their role in

J. P. Pointier; P. David; P. Jarne

2005-01-01

268

What happens when snails get sick?  

NSDL National Science Digital Library

Scientists used to think that the two major groups of animals, vertebrates and invertebrates, protected themselves from getting sick in very different ways. A new study in snails suggests that both groups' immune systems might be slightly more similar than previously thought.

American Association for the Advancement of Science (AAAS; )

2004-07-09

269

Differential Role of Snail1 and Snail2 Zinc Fingers in E-cadherin Repression and Epithelial to Mesenchymal Transition*  

PubMed Central

Snail1 (Snail) and Snail2 (Slug) are transcription factors that share a similar DNA binding structure of four and five C2H2 zinc finger motifs (ZF), respectively. Both factors bind specifically to a subset of E-box motifs (E2-box: CAGGTG/CACCTG) in target promoters like the E-cadherin promoter and are key mediators of epithelial-to-mesenchymal transition (EMT). However, there are differences in the biological actions, in binding affinities to E-cadherin promoter, and in the target genes of Snail1 and Snail2, although the molecular bases are presently unknown. In particular, the role of each Snail1 and Snail2 ZF in the binding to E-boxes and in EMT induction has not been previously explored. We have approached this question by modeling Snail1 and Snail2 protein-DNA interactions and through mutational and functional assays of different ZFs. Results show that Snail1 efficient repression and binding to human and mouse E-cadherin promoter as well as EMT-inducing ability require intact ZF1 and ZF2, while for Snail2, either ZF3 or ZF4 is essential for those functions. Furthermore, the differential distribution of E2-boxes in mouse and human E-cadherin promoters also contributes to the differential Snail factor activity. These data indicate a non-equivalent role of Snail1 and Snail2 ZFs in gene repression, contributing to the elucidation of the molecular differences between these important EMT regulators. PMID:24297167

Villarejo, Ana; Cortés-Cabrera, Álvaro; Molina-Ortíz, Patricia; Portillo, Francisco; Cano, Amparo

2014-01-01

270

Freshwater molluscs as indicators of bioavailability and toxicity of metals in surface-water systems.  

PubMed

Freshwater molluscs--snails and bivalves--have been used frequently as bioindicator organisms. With increasing needs for research on contaminant effects in freshwater ecosystems, this kind of biomonitoring is likely to develop further in the future. Molluscs can be used effectively for studies of both organic and inorganic contaminants; this review focuses on studies involving bioaccumulation and toxicity of metals. Two important advantages of snails and bivalves over most other freshwater organisms for biomonitoring research are their large size and limited mobility. In addition, they are abundant in many types of freshwater environments and are relatively easy to collect and identify. At metal concentrations that are within ranges common to natural waters, they are generally effective bioaccumulators of metals. Biomonitoring studies with freshwater molluscs have covered a wide diversity of species, metals, and environments. The principal generalization that can be drawn from this research is that bioaccumulation and toxicity are extremely situation dependent; hence, it is difficult to extrapolate results from any particular study to other situations where the biological species or environmental conditions are different. Even within one species, individual characteristics such as size, life stage, sex, and genotype can have significant effects on responses to contaminants. The bioavailability of the metal is highly variable and depends on pH, presence of organic ligands, water hardness, and numerous other controlling factors. Despite this variability, past studies provide some general principles that can facilitate planning of research with freshwater snails and bivalves as metal bioindicators. These principles may also be useful in understanding and managing freshwater ecosystems. Bioaccumulation of metals in biota is a function of both uptake and depuration. Uptake in molluscs may be through either of two vectors--ingestion of food and other metal-containing substances or through direct adsorption of dissolved constituents. Under some conditions, the bioconcentration factors can be in the range of 10(3) to 10(6), relative to water. Most studies that provide comparisons among taxonomic groups indicate that bioaccumulation in molluscs is greater than that is fish. However, such comparisons should be interpreted with caution because metals tend to be nonuniformly distributed among different organs in both molluscs and fish. Bioaccumulation and acute and chronic toxicity are highly dependent on metal speciation. Mainly because of this influence of metal speciation, toxicity and bioaccumulation do not have a consistent relation to each other. Sensitivity to toxic effects of a metal is likely to be considerably greater in juvenile or larval stages than in adults. PMID:1771274

Elder, J F; Collins, J J

1991-01-01

271

JUVENILE SNAILS, ADULT APPETITES: CONTRASTING RESOURCE CONSUMPTION BETWEEN TWO SPECIES OF APPLESNAILS  

E-print Network

., 2006). Beyond size differences between species, larger size of adult snails compared to their juvenileJUVENILE SNAILS, ADULT APPETITES: CONTRASTING RESOURCE CONSUMPTION BETWEEN TWO SPECIES October 2007) ABSTRACT Research on aquatic snails usually examines consumption of periphyton

Burks, Romi

272

Biomes: Freshwater and Seawater  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. Students conduct research by sampling organisms in a nearby freshwater habitat to determine how an organism's behavior and adaptation relate to its habitat, and how freshwater habitats have different characteristics depending on whether water is still or moving. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

273

Genotoxicity of platinum in embryos of zebrafish (Danio rerio) and ramshorn snail (Marisa cornuarietis).  

PubMed

The metal platinum is inter alia used for industrial and medical purposes. Due to its application in automobile catalytic converters and as an anti-cancer drug, Pt enters the aquatic environment via road runoff and hospital sewage and raises concerns about its environmental impact and toxicity to organisms. Therefore, the genotoxicity of Pt at 0, 0.1, 1, 10, 50, 100 and 200?g/l PtCl(2) was tested on two freshwater organisms, zebrafish (Danio rerio) and ramshorn snail (Marisa cornuarietis) using the single cell gel electrophoresis, also called comet assay. PtCl(2) did not show any genotoxicity for D. rerio at the tested concentrations, whereas significantly elevated DNA damage was observed in M. cornuarietis at 1?g/l PtCl(2) and beyond. The results of the study suggest a high sensitivity of M. cornuarietis concerning the genotoxic impact of PtCl(2). PMID:21420724

Osterauer, Raphaela; Fassbender, Christopher; Braunbeck, Thomas; Köhler, Heinz-R

2011-05-01

274

Bisphenol A Induces Superfeminization in the Ramshorn Snail (Gastropoda: Prosobranchia) at Environmentally Relevant Concentrations  

PubMed Central

Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 ?g/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experimentation. Therefore, the objective of the current approach was to bridge several gaps in knowledge by conducting additional experiments. In an initial series of experiments, study results from the reproductive phase of the snails were evaluated in the sub-micrograms per liter range. Before and after the spawning season, superfemale responses were observed [NOEC (no observed effect concentration) 7.9 ng/L, EC10 (effective concentration at 10%) 13.9 ng/L], which were absent during the spawning season. A further experiment investigated the temperature dependence of BPA responses by exposing snails at two temperatures in parallel. The adverse effect of BPA was at least partially masked at 27°C (EC10 998 ng/L) when compared with 20°C (EC10 14.8 ng/L). In M. cornuarietis, BPA acts as an estrogen receptor (ER) agonist, because effects were completely antagonized by a co-exposure to tamoxifen and Faslodex. Antiandrogenic effects of BPA, such as a significant decrease in penis length at 20°C, were also observed. Competitive receptor displacement experiments indicate the presence of androgen- and estrogen-specific binding sites. The affinity for BPA of the estrogen binding sites in M. cornuarietis is higher than that of the ER in aquatic vertebrates. The results emphasize that prosobranchs are affected by BPA at lower concentrations than are other wildlife groups, and the findings also highlight the importance of exposure conditions. PMID:16818258

Oehlmann, Jörg; Schulte-Oehlmann, Ulrike; Bachmann, Jean; Oetken, Matthias; Lutz, Ilka; Kloas, Werner; Ternes, Thomas A.

2006-01-01

275

Competitive displacement of a detritivorous salt marsh snail  

Microsoft Academic Search

Here we examine the role of competitive interactions in controlling distributions of the most abundant omnivore–detritivore snails in East Coast U.S. salt marshes (Melampus bidentatus and Littoraria irrorata). Both snails prefer to eat fungi growing on plant material, and the periwinkle Littoraria, a much larger snail, destroys marsh canopy when grazing fungal-infected plants, resulting in increased local desiccation stress. To

Sarah C. Lee; Brian Reed Silliman

2006-01-01

276

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

PubMed

Fascioliasis caused by Fasciola hepatica was a serious problem for sheep and alpacas in the Altiplano Region of Bolivia. In some provinces close to Lake Titicaca, the raising of sheep was forced to discontinue, because infection with the fluke made it unprofitable and almost impossible. It was proved that in the Altiplano Region, two species of freshwater snails, Lymnaea viatrix and L. cubensis var., served as intermediate hosts for F. hepatica. In some subtropical areas of Bolivia, these snails could not be found, although other Lymnaea sp. was widely distributed there. As it is possible for Lymnaea sp. to be intermediate host for the fluke, further studies are required on the identification. Acute fascioliasis of sheep occurred in the Altiplano Region principally during a period from May to July, or the dry season. In some areas, the mortality rate of infected sheep was roughly estimated as 15 to 25% annually. Contamination with Fasciola metacercariae of herbage and semi-aquatic plants grown in a swamp in one of these areas was biologically assessed, using guinea pigs. Plants of Compositae and Eleocharis sp. were contaminated most intensely and those of Senicio sp. and Vallisneria sp. carried a fairly large number of cysts, while plants of Scirpus sp. and Ranunclaceae carried only a few cysts. No signs of Fasciola infection were observed in any animal given the plants of Liliaceae. PMID:1182037

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

1975-01-01

277

Acute toxic effects of two lampricides on twenty-one freshwater invertebrates  

USGS Publications Warehouse

We conducted laboratory static bioassays to determine acute toxicity of two lampricides -- a 70% 2-aminoethanol salt of 5,2'dichloro-4'-nitrosalicylanilide (Bayer 73) and a mixture containing 98% 3-trifluoromethyl-4-nitrophenol (TFM) and 2% Bayer 73 (TFM-2B) -- to 21 freshwater invertebrates. LC50 values were determined for 24-h exposure periods at 12.8 C. Organisms relatively sensitive to Bayer 73 were a turbellarian (Dugesia tigrina), aquatic earthworms (Tubifex tubifex and Lumbriculus inconstans), snails (Physa sp.) and (Pleurocera sp.), a clam (Eliptio dilatatus), blackflies (Simulium sp.), leeches (Erpobdellidae), and a daphnid (Daphnia pulex). The invertebrates most sensitive to TFM-2B were turbellarians, aquatic earthworms (Tubifex), snails (Physa), blackflies, leeches, and burrowing mayflies (Hexagenia sp.). Bayer 73 was generally much more toxic to the test organisms than TFM-2B. At lampricidal concentrations, TFM-2B was more highly selective than Bayer 73 against larval sea lampreys (Petromyzon marinus).

Rye, Robert P., Jr.; King, Everett Louis, Jr.

1976-01-01

278

Biological studies on the snail, Bulinus truncatus, in central Iraq*  

PubMed Central

This paper presents some results of field and laboratory studies on Bulinus truncatus, the snail intermediate host of urinary bilharziasis in Iraq, made in 1958 as part of the work of the WHO Bilharziasis Control Project in that country. Observations on the linear distribution and size composition of Bulinus populations in the canals of central Iraq indicate that molluscicides might most suitably be applied in May before the entire snail population reaches breeding size, or early in November when most snails are juveniles. However, laboratory experiments appear to show that isolation of individual bulinid snails does not diminish, but may actually increase, their egg-laying capacity in comparison with that of grouped snails; this suggests that, even if the snail population were drastically reduced by treatment of the canals and all further importation of snails rendered impossible, the snail population would nevertheless soon renew itself from the few individuals remaining. Results are also given of laboratory experiments on egg masses, hatching and growth of B. truncatus and on the egg-laying of random populations of that snail. PMID:14478049

Najarian, H. H.

1961-01-01

279

Freshwater Marsh. Habitat Pac.  

ERIC Educational Resources Information Center

The materials in this educational packet are designed for use with students in grades 4 through 7. They consist of an overview, three lesson plans and student data sheets, and a poster. The overview describes how the freshwater marsh is an important natural resource for plant, animal, and human populations and how the destruction of marshes causes…

Fish and Wildlife Service (Dept. of Interior), Washington, DC.

280

Loons in freshwater lakes  

Microsoft Academic Search

Loons (Gaviidae) divide their annual cycle between salt and freshwater habitat, the latter being the site of breeding activites. Territorial requirements include sufficient size to permit runs of more than 100 m for take-off and landings; food for chicks and water clarity sufficient to permit foraging for it at depths generally = 5 m; protected nest sites, preferably islands; and

Judith W. McIntyre

1994-01-01

281

Crayfish predation on the common pond snail (Lymnaea stagnalis): the effect of habitat complexity and snail size on foraging efficiency  

Microsoft Academic Search

Optimal foraging theory was used to explain selective foraging by the introduced signal crayfish (Pacifastacus leniusculus)\\u000a on the thin-shelled common pond snail (Lymnaea stagnalis). Crayfish predation efficiency was studied in relation to habitat\\u000a complexity and snail size. In a pool experiment (area 1.3 m2) single adult crayfish were allowed to feed on four size classes of snails for one week.

Per Nyström; Jose R. Pérez

1998-01-01

282

Variation of snail's abundance in two water bodies harboring strains of Pseudosuccinea columella resistant and susceptible to Fasciola hepatica miracidial infection, in Pinar del Río Province, Cuba.  

PubMed

The abundance of freshwater snails in two rural sites of Pinar del Río, Cuba, which harbor Pseudosuccinea columella susceptible and resistant to miracidia of Fasciola hepatica was followed for one year. Susceptible snails were found in the most anthropic site (IPA) whereas the resistant population inhabited the most preserved one (El Azufre). Only two snail species coexisted with P. columella at IPA site (Physa cubensis and Tarebia granifera) while five species were found at El Azufre, including an endemic from that province (Hemisinus cubanianus). Populations of both resistant and susceptible snails showed stable densities throughout the year, although the susceptible strain attained higher abundance. The highest densities were observed in April-May 2004 for the susceptible population whereas the resistant strain attained its highest abundance in January 2004. No record of Fossaria cubensis was made and the thiarid T. granifera occurred only at low densities. One of the sampled sites (IPA) meets all the conditions for the first report of P. columella naturally infected with larvae of F. hepatica. PMID:16410958

Gutiérrez, Alfredo; Hernandez, Dagmar F; Sánchez, Jorge

2005-11-01

283

How a single gene twists a snail.  

PubMed

The gastropod Lymnaea has unique features, that is, chirality, sinistrality, or dextrality, is displayed externally as well as internally, and is hereditary, being determined by a single-locus that functions maternally at the very early embryonic stage. Both sinistral and dextral snails exist in nature with the dextral one being dominant. Thus, the genus Lymnaea is an ideal target for studying chiromorphogenesis. This article gives a brief overview of the current state of research on chiromorphogenesis of Lymnaea (L.) stagnalis, mainly focusing on our own studies. Breeding experiments were performed and embryonic development was closely observed for the both chiralities. By fluorescently labeling filamentous actin and microtubules, cytoskeletal dynamics of spiral cleavages for the sinistral and dextral embryos were shown not to be mirror images of each other at the critical third-cleavage. The spiral deformation and spindle inclination were uniquely observed only in the dominant dextral embryos, and they were shown to be strongly linked to the gene determining the direction of chirality. Based on these findings, we created fertile snails of situs inversus by micromanipulation at the third-cleavage. Surprisingly, the arrangement of the blastomere regulates asymmetric expression of nodal-Pitx genes in later development. The expression patterns display interesting similarity and dissimilarity with those of the vertebrates. Thus, study of L. stagnalis has given an insight into "how a single gene twists a snail." PMID:24994072

Kuroda, Reiko

2014-10-01

284

Increases in urea synthesis and the ornithine-urea cycle capacity in the giant African snail, Achatina fulica, during fasting or aestivation, or after the injection with ammonium chloride.  

PubMed

The objectives of this study are to determine whether a full complement of ornithine-urea cycle (OUC) enzymes is present in the hepatopancreas of the giant African snail Achatina fulica, and to investigate whether the rate of urea synthesis and the OUC capacity can be up-regulated during 23 days of fasting or aestivation, or 24 hr post-injection with NH(4)Cl (10 micromol g(-1) snail) into the foot muscle. A. fulica is ureotelic and a full complement of OUC enzymes, including carbamoyl phosphate synthetase III (CPS III), was detected from its hepatopancreas. There were significant increases in the excretion of NH(4)(+), NH(3) and urea in fasting A. fulica. Fasting had no significant effect on the tissue ammonia contents, but led to a progressive accumulation of urea, which was associated with an 18-fold increase in the rate of urea synthesis. Because fasting took place in the presence of water and because there was no change in water contents in the foot muscle and hepatopancreas, it can be concluded that the function of urea accumulation in fasting A. fulica was unrelated to water retention. Aestivation in arid conditions led to a non-progressive accumulation of urea in A. fulica. During the first 4 days and the last 3 days of the 23-day aestivation period, experimental snails exhibited significantly greater rates of urea synthesis compared with fasted snails. These increases were associated with significant increases in activities of various OUC enzymes, except CPS III, in the hepatopancreas. However, the overall urea accumulation in snails aestivated and snails fasted for 23 days were comparable. Therefore, the classical hypothesis that urea accumulation occurred to prevent water loss through evaporation during aestivation in terrestrial pulmonates may not be valid. Surprisingly, there were no accumulations of ammonia in the foot muscle and hepatopancreas of A. fulica 12 or 24 hr after NH(4)Cl was injected into the foot muscle. In contrast, the urea content in the foot muscle of A. fulica increased 4.5- and 33-fold at hour 12 and hour 24, respectively, and the respective increases in the hepatopancreas were 4.9- and 32-fold. The exogenous ammonia injected into A. fulica was apparently detoxified completely to urea. The urea synthesis rate increased 148-fold within the 24-hr experimental period, which could be the greatest increase known among animals. Simultaneously, there were significant increases in activities of glutamine synthetase (2.5-fold), CPS III (3.1-fold), ornithine transcarbamoylase (2.3-fold), argininosuccinate synthetase+lyase (13.6-fold) and arginase (3.5-fold) in the hepatopancreas 12 hr after the injection of NH(4)Cl. Taken altogether, our results support the view that the primary function of urea synthesis through the OUC in A. fulica is to defend against ammonia toxicity, but suggest that urea may have more than an excretory role in terrestrial pulmonates capable of aestivation. PMID:16254923

Hiong, Kum Chew; Loong, Ai May; Chew, Shit Fun; Ip, Yuen Kwong

2005-12-01

285

Rare and endangered species: freshwater gastropods of southern New England  

SciTech Connect

The rare and endangered species of freshwater gastropods of southern New England are reported on based upon data collected over the past four years. Field sampling was concentrated in Connecticut but included parts of southern Massachusetts east to Cape Code (69 55 W to 73 45'W, 40 00'N). Water chemistry data were collected along with the snails. Collection methods and water analysis techniques have been described elsewhere by Jokinen (The Nautilus 92:156-160, 1978). Voucher specimens have been placed in the Museum of Comparative Zoology, Harvard University, The Florida State Museum, and the Museum of Zoology, the University of Michigan. Acid rain poses a threat to poorly buffered habitats. 6 references, 1 table.

Jokinen, E.H.; Pondick, J.

1981-01-01

286

Expression profiling and binding properties of fibrinogen-related proteins (FREPs), plasma proteins from the schistosome snail host Biomphalaria glabrata  

PubMed Central

A growing body of evidence suggests an important role for fibrinogen-like proteins in innate immunity in both vertebrates and invertebrates. It has been shown that fibrinogen-related proteins (FREPs), plasma proteins present in the freshwater snail Biomphalaria glabrata, the intermediate host for the human blood fluke Schistosoma mansoni, are diverse and involved in snail innate defense responses. To gain further insight into the functions of FREPs, recombinant FREP proteins (rFREPs) were produced in Escherichia coli and antibodies (Abs) were raised against the corresponding rFREPs. We first show that most FREP proteins exist in their native conformation in snail hemolymph as multimeric proteins. Western blot analyses reveal that expression of multiple FREPs including FREP4 in plasma from M line and BS-90 snails, which are susceptible and resistant to S. mansoni infection, respectively, is up-regulated significantly after infection with the trematode Echinostoma paraensei. Moreover, our assays demonstrate that FREPs are able to bind E. paraensei sporocysts and their secretory/excretory products (SEPs), and a variety of microbes (Gram-positive and Gram-negative bacteria and yeast). Furthermore, this binding capability shows evidence of specificity with respect to pathogen type; for example, 65–75-kDa FREPs (mainly FREP4) bind to E. paraensei sporocysts and their SEPs whereas 95-kDa and 125-kDa FREPs bind the microbes assayed. Our results suggest that FREPs can recognize a wide range of pathogens, from prokaryotes to eukaryotes, and different categories of FREPs seem to exhibit functional specialization with respect to the pathogen encountered. PMID:18562576

Zhang, Si-Ming; Zeng, Yong; Loker, Eric S.

2013-01-01

287

Nimbus (BgI): An active non-LTR retrotransposon of the Schistosoma mansoni snail host Biomphalaria glabrata?  

PubMed Central

The freshwater snail Biomphalaria glabrata is closely associated with the transmission of human schistosomiasis. An ecologically sound method has been proposed to control schistosomiasis using genetically modified snails to displace endemic, susceptible ones. To assess the viability of this form of biological control, studies towards understanding the molecular makeup of the snail relative to the presence of endogenous mobile genetic elements are being undertaken since they can be exploited for genetic transformation studies. We previously cloned a 1.95 Kb BamHI fragment in B. glabrata (BGR2) with sequence similarity to the human long interspersed nuclear element (LINE or L1). A contiguous, full-length sequence corresponding to BGR2, hereafter-named nimbus (BgI), has been identified from a B. glabrata bacterial artificial chromosome (BAC) library. Sequence analysis of the 65,764 bp BAC insert contained one full-length, complete nimbus (BgI) element (element I), two full-length elements (elements II and III) containing deletions and flanked by target site duplications and 10 truncated copies. The intact nimbus (BgI) contained two open reading frames (ORFs 1 and 2) encoding the characteristic hallmark domains found in non-long terminal repeat retrotransposons belonging to the I clade; a nucleic acid binding protein in ORF1 and an apurinic/apyrimidinic endonuclease, reverse transcriptase and RNase H in ORF2. Phylogenetic analysis revealed that nimbus (BgI) is closely related to Drosophila (I factor), mosquito Aedes aegypti (MosquI) and chordate ascidian Ciona intestinalis (CiI) retrotransposons. Nimbus (BgI) represents the first complete mobile element characterized from a mollusk that appears to be transcriptionally active and is widely distributed in snails of the neotropics and the Old World. PMID:17521654

Raghavan, Nithya; Tettelin, Hervé; Miller, André; Hostetler, Jessica; Tallon, Luke; Knight, Matty

2009-01-01

288

Environmentally relevant concentrations of a common insecticide increase predation risk in a freshwater gastropod.  

PubMed

Ecological receptors are faced with a multitude of stressors that include abiotic and biotic factors creating a challenge for assessing risk of chemical exposure. Of particular interest and importance are the effects of contaminants on inter-species interactions such as competition and predator-prey relationships. The objective of this study was to determine whether environmentally relevant concentrations of the commonly used insecticide, malathion, would alter predator avoidance behavior in a freshwater gastropod that could translate to increased predation risk. We exposed adult Physa pomilia snails to 0, 0.25, or 1.0 mg/L malathion for 2, 24, or 48 h and evaluated predator avoidance using a behavioral assay in which snails were exposed to cues from predatory crayfish. We found a significant reduction in predator avoidance in snails exposed to both concentrations of malathion after 48 h of exposure. To evaluate whether observed effects of malathion on predator avoidance actually increased susceptibility of snails to predators, we conducted a predator challenge experiment. Snails exposed to 0.25 mg/L malathion for 48 h were significantly more susceptible to predation. That increased predation risk was evident 48 h after initial malathion exposures is a unique result because most studies have evaluated behavioral responses soon after (<12 h) initiation of pesticide exposure. The extent to which the observed interactions affect natural populations, and the mechanisms through which they are mediated are largely unexplored. However, our study is the first to show that a commonly used insecticide decreases predator avoidance and may actually increase predation susceptibility in gastropods at concentrations several orders of magnitude below acute toxicity levels. PMID:23053786

Salice, Christopher J; Kimberly, David A

2013-01-01

289

The Snail Resource of the Eastern Berin9 Sea  

E-print Network

of highest concentration also supporting a high biomass of fish and epibenthic inverte- brates. Snail biomassThe Snail Resource of the Eastern Berin9 Sea and Its Fishery RICHARD A. MaciNTOSH Buccinum sp resources. Fish and crab resources are well known and have long been exploited by many fishing nations

290

Competitive displacement and predation between introduced and native mud snails  

Microsoft Academic Search

Experimental field and laboratory studies indicate that Cerithidea californica, a native mud snail, is restricted to only a portion of its normal habitat range in San Francisco Bay as a result of direct interactions with an introduced ecological equivalent, Ilyanassa obsoleta. The native snail typically inhabits marsh pans, tidal creeks and mudflats in estuaries along the Pacific coast. However, in

Margaret Seluk Race

1982-01-01

291

Vineyard snail Cernuella virgata Michigan State University's invasive species factsheets  

E-print Network

and snail-contaminated crops had reduced marketability. Michigan risk maps for exotic plant pests. Other and plant hosts The snail primarily feeds on decaying organic matter. It also feeds on seedlings of cereals to the heads and stalks of plants or fences and enter dormancy (called aestivation). The life cycle is annual

292

Snail silencing effectively suppresses tumour growth and invasiveness  

Microsoft Academic Search

The transcription factor Snail has been recently proposed as an important mediator of tumour invasion because of its role in downregulation of E-cadherin and induction of epithelial–mesenchymal transitions (EMT). This behaviour has led to the consideration of Snail as a potential therapeutic target to block tumour progression. In this report, we provide evidence for this hypothesis. We show that silencing

D Olmeda; M Jordá; H Peinado; Á Fabra; A Cano

2007-01-01

293

Freshwater Pollution and Treatment  

NSDL National Science Digital Library

This teaching resource was developed by a K-12 science teacher in the American Physiological SocietyÂ?s 2008 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org. This laboratory experiment teaches students the effects of pollutants on water quality and the impact it has on living organisms through fresh water quality testing of different environmental sources. Students should have some prior knowledge of the properties of water and a basic understanding of freshwater resources before beginning this activity. Upon completion of this activity, students will be able to: know how pollutants affect freshwater sources, interpret the most efficient tests to perform on water samples based on where the water originates, and analyze the affects pollutants have on water quality.

Michael Griffin (Brogden Middle School)

2008-08-01

294

Octopamine boosts snail locomotion: behavioural and cellular analysis.  

PubMed

We measured the reduction in locomotion of unrestrained pond snails, Lymnaea stagnalis, subsequent to transdermal application of two selective octopamine antagonists, epinastine and phentolamine. After 3 h in fresh standard snail water following treatment with 4 mM epinastine or 3.5 mM phentolamine, the snails' speed was reduced to 25 and 56% of the controls (P < 0.001 and P = 0.02, respectively). The snails' speed decreased as the drug concentration increased. In the isolated CNS, 0.5 mM octopamine increased the firing rate of the pedal A cluster motoneurons, which innervate the cilia of the foot. In normal saline the increase was 26% and in a high magnesium/low calcium saline 22% (P < 0.05 and 0.01, respectively). We conclude that octopamine is likely to modulate snail locomotion, partially through effects on pedal motoneurons. PMID:17072577

Ormshaw, Jennifer C; Elliott, Christopher J H

2006-12-01

295

The Mitochondrial Genome of the Venomous Cone Snail Conus consors  

PubMed Central

Cone snails are venomous predatory marine neogastropods that belong to the species-rich superfamily of the Conoidea. So far, the mitochondrial genomes of two cone snail species (Conus textile and Conus borgesi) have been described, and these feed on snails and worms, respectively. Here, we report the mitochondrial genome sequence of the fish-hunting cone snail Conus consors and describe a novel putative control region (CR) which seems to be absent in the mitochondrial DNA (mtDNA) of other cone snail species. This possible CR spans about 700 base pairs (bp) and is located between the genes encoding the transfer RNA for phenylalanine (tRNA-Phe, trnF) and cytochrome c oxidase subunit III (cox3). The novel putative CR contains several sequence motifs that suggest a role in mitochondrial replication and transcription. PMID:23236512

Brauer, Age; Kurz, Alexander; Stockwell, Tim; Baden-Tillson, Holly; Heidler, Juliana; Wittig, Ilka; Kauferstein, Silke; Mebs, Dietrich; Stöcklin, Reto; Remm, Maido

2012-01-01

296

Acidification of freshwaters  

SciTech Connect

This volume gives an account that draws not only on the main branches of chemistry but also on soil physics, chemistry, hydrology, meteorology, geography, geology, plant physiology, soil microbiology and zoology. The author examine the numerous interacting physical, chemical, and biological, processes that regulate the acidity of freshwaters, a phenomenon that has various causes, including precipitation; acidifying pollutions; and the interaction of plants, soils and water. The relative importance of the different processes is examined.

Cresser, M.S.; Edwards, A.C.

1987-01-01

297

Morphological and Genetic Variation Between the Japanese Populations of the Amphidromous Snail Stenomelania crenulata (Cerithioidea: Thiaridae).  

PubMed

Freshwater gastropods often have limited dispersal capability and small geographic ranges, and face severe threats from habitat loss and degradation. However, in addition to the scarcity of knowledge on their life history traits, species taxonomy has not been adequately resolved and boundaries between intra- and interspecific variation remain unclear for many taxa. One such example of an indeterminate species boundary with implications for conservation issues is the relationship between the thiarid snails Stenomelania crenulata in Okinawa and southwards (ranked as CR+EN in the 2012 Japanese Red List) and S. rufescens in mainland Japan (VU). The results of our multi-disciplinary investigation into variation in the shell morphology and mitochondrial (COI) and nuclear (ITS-1) gene sequences suggest that S. rufescens represents a geographic variant and a junior synonym of S. crenulata. The widespread geographic range of S. crenulata, spanning a few thousand kilometers north to south, is possible due to an amphidromous life cycle that involves a marine planktotrophic larval phase and upstream migration after settlement in estuaries. Nevertheless, there is recognizable morphological and genetic differentiation between distant populations, probably reflecting a relatively short pelagic duration and possibly also infrequent transoceanic dispersal; metamorphic competence is achieved in two weeks in full seawater and even more rapidly in brackish water. The Okinawan population, with only a few known localities, therefore deserves the high conservation priority; conservation efforts need to involve the proper maintenance of migration pathways including all marine, brackish and freshwater environments. PMID:25186931

Hidaka, Hiroka; Kano, Yasunori

2014-09-01

298

Limestone and the problem of radiocarbon dating of land-snail shell carbonate  

Microsoft Academic Search

In order to test the role of limestone in producing anomalously old radiocarbon ages in land-snail shells, 14C analyses were performed on shell carbonate of modern land snails from limestone and nonlimestone areas of Jamaica. No anomaly was found in snails from the nonlimestone area, implying that such material is suitable for radiocarbon dating. Snails from limestone areas produced variable

Glenn A. Goodfriend; Jerry J. Stipp

1983-01-01

299

How parasitism, stream substrate, and movement patterns mediate response to disturbance in the snail Elimia flava  

NASA Astrophysics Data System (ADS)

Snails in the genus Elimia are abundant in southeastern USA streams, and also serve as intermediate hosts to parasitic trematodes. Previous work indicated that high-flows decrease snail abundance and trematode prevalence, and others have shown substrate type and snail size affect likelihood of snail dislodgement. To investigate how parasitism, size, substrate, and snail behavior influenced dislodgement, we placed Elimia flava in artificial streams containing tile or gravel substrates, and then exposed them to progressively increasing flow velocities ( ~10, 40, 90 cm/s) for 5 minutes each. We recorded snail behavior and time to dislodgement, and then preserved snails to quantify their size and parasite load. Snails on tile dislodged significantly faster than snails on gravel, and snails with high parasite loads also dislodged faster than snails without parasites. Parasitism also appeared to affect movement patterns: snails showing predominantly downstream movement had higher parasite loads than those that did not. Behavior also affected dislodgement probability, as snails moving upstream or to the waterline remained on the substrate longer than snails not showing those behaviors. Parasitism, substrate composition, and snail movement are useful predictors of the likelihood of dislodgement, and parasitism and substrate may both increase snail vulnerability to flow disturbance.

Tomba, A. M.; Feminella, J. W.

2005-05-01

300

Responses of Mud Snails and Periwinkles to Environmental Odors and Disaccharide Mimics of Fish Odor  

Microsoft Academic Search

Estuarine snails, periwinkles (Littoraria irorata), and mud snails (Ilyanassa obsoleta) were tested for behavioral responses to aqueous extracts of tissue macerates, odors of living intact organisms, and to disaccharides derived from heparin. Extracts included salt-marsh cordgrass (Spartina alterniflora), pink shrimp (Penaeus duorarum), crushed periwinkles, and crushed mud snails. Odors included live periwinkles, mud snails, stone crab (Menippe mercenaria), striped hermit

Yasmin J. Rahman; Richard B. Forward; Dan Rittschof

2000-01-01

301

A SNAIL'S SPACE SETS A SNAIL'S PACE: MOVEMENT RATES OF LAVIGERIA GASTROPODS IN LAKE TANGANYIKA, EAST AFRICA  

E-print Network

A SNAIL'S SPACE SETS A SNAIL'S PACE: MOVEMENT RATES OF LAVIGERIA GASTROPODS IN LAKE TANGANYIKA gastropods are diverse and common in the benthos of Lake Tanganyika. We used in situ studies of marked of three closely related species of gastropods in Lake Tanganyika. In addition to potential interspecific

McIntyre, Peter

302

Toxicity of Common Aquaculture Disinfectants to New Zealand Mud Snails and Mud Snail Toxicants to Rainbow Trout Eggs  

Microsoft Academic Search

The New Zealand mud snail (NZMS) Potamopyrgus antipodarum is an invasive species that threatens North American fish populations. Establishment of NZMS in fish hatcheries is a concern because fish stocking practices could expedite the spread of the species. We evaluated the potential use of chemicals to remove snails that are inadvertently collected during egg take operations involving wild broodstock from

Randall W. Oplinger; Eric J. Wagner

2009-01-01

303

Modeling snail breeding in Bioregenerative Life Support System  

NASA Astrophysics Data System (ADS)

It is known that snail meat is a high quality food that is rich in protein. Hence, heliciculture or land snail farming spreads worldwide because it is a profitable business. The possibility to use the snails of Helix pomatia in Biological Life Support System (BLSS) was studied by Japanese Researches. In that study land snails were considered to be producers of animal protein. Also, snail breeding was an important part of waste processing, because snails were capable to eat the inedible plant biomass. As opposed to the agricultural snail farming, heliciculture in BLSS should be more carefully planned. The purpose of our work was to develop a model for snail breeding in BLSS that can predict mass flow rates in and out of snail facility. There are three linked parts in the model called “Stoichiometry”, “Population” and “Mass balance”, which are used in turn. Snail population is divided into 12 age groups from oviposition to one year. In the submodel “Stoichiometry” the individual snail growth and metabolism in each of 12 age groups are described with stoichiometry equations. Reactants are written on the left side of the equations, while products are written on the right side. Stoichiometry formulas of reactants and products consist of four chemical elements: C, H, O, N. The reactants are feed and oxygen, products are carbon dioxide, metabolic water, snail meat, shell, feces, slime and eggs. If formulas of substances in the stoichiometry equations are substituted with their molar masses, then stoichiometry equations are transformed to the equations of molar mass balance. To get the real mass balance of individual snail growth and metabolism one should multiply the value of each molar mass in the equations on the scale parameter, which is the ratio between mass of monthly consumed feed and molar mass of feed. Mass of monthly consumed feed and stoichiometry coefficients of formulas of meat, shell, feces, slime and eggs should be determined experimentally. An age structure and size of snail population are optimized on the base of individual growth and metabolic characteristics with the help of the second submodel "Population". In this simulation a daily amount of snail meat consumed by crewmembers is a guideline which specifies population productivity. Also, the daily amount of snail meat may have an optional value. Prescribed population characteristics are used in the third submodel "Mass balance" to equalize input and output mass flow rates of snail facility. In this submodel we add a water and ash to the organic masses of feed, meat, feces, shell and eggs. Moreover, masses of calcium carbonate and potable water are added to the left side of mass balance equations. Mass of calcium carbonate is distributed among shell, feces and eggs. Summarizing the twelve equations for each snail age, we get the mass balance equation for the snail facility. All simulations are performed by using Solver Add-In for Excel 2007.

Kovalev, Vladimir; Tikhomirov, Alexander A.; Nickolay Manukovsky, D..

304

Toxicity of metals to a freshwater tubificid worm Tubifex tubifex (Muller)  

SciTech Connect

Salts of various metals are being released in ever increasing amounts into the aquatic environment from mining operations, metal processing facilities, chemical industries and other similar sources. Although there has been considerable study of the acute and chronic toxicities of metals to freshwater fishes, crustaceans and snails, little information is available on the effects of metals to tubificid worms which are widely distributed in the aquatic environment. Tubificid worms are useful indicators of varying degrees of aquatic pollution. It is suggested that tubificid worms are an important element in the aquatic environment and therefore their use as a bioassay organism is logical one. The present study was undertaken to determine the acute toxicities of various metals to a fresh-water tubificid worm, Tubifex tubifex (Muller), which form an important link in aquatic food chain(s).

Khangarot, B.S. (Industrial Toxicology Research Centre, Lucknow (India))

1991-06-01

305

Effects of pollution on freshwater organisms  

SciTech Connect

This review includes subjects in last year's reviews on effects of pollution on freshwater invertebrates and effects of pollution on freshwater fish and amphibians. This review also includes information on the effects of pollution on freshwater plants. 625 references.

Phipps, G.L.; Harden, M.J.; Leonard, E.N.; Roush, T.H; Spehar, D.L.; Stephan, C.E.; Pickering, Q.H.; Buikema, A.L. Jr.

1984-06-01

306

Causes of Late Pleistocene water level change in Lake Victoria, Equatorial East Africa, derived from clumped isotopes of land snails and fresh water mollusks. (Invited)  

NASA Astrophysics Data System (ADS)

Carbonate clumped isotope thermometry is based on the dependence of 13C-18O bond abundance in the carbonate lattice (measured as ?47) on the carbonate formation temperature. Most marine and freshwater biogenic carbonates are found to be in agreement with the clumped isotopes - temperature calibration. Clumped isotope thermometry is particularly useful in terrestrial environments where the interpretation of carbonate ?18O is limited due to difficulty in estimating the paleo-water isotopic composition. Clumped isotope-derived temperatures from land snails are generally higher than the ambient environmental temperatures, but show no evidence for disequilibrium. We attribute these higher body temperatures to snail eco-physiological adaptations through shell color, morphology, and behavior. We use the clumped isotope-derived temperatures in combination with shell ?18O to calculate snail body water ?18O composition. This parameter is interpreted as a paleo-hydrological indicator that reflects the isotopic composition of local precipitation modified by local evaporation. Rusinga and Mfangano Islands in Lake Victoria provide a unique opportunity to compare extant species of modern and fossil freshwater mollusks and land snails from the same location to examine lake paleo-hydrology. This location is particularly interesting as Lake Victoria itself is the main source of rain-water in the region such that the isotopic composition of land snail body water can be related back to the source waters. We combine clumped isotope and oxygen isotope measurements of both freshwater mollusks and land snails to examine the water balance of the lake, testing hypotheses about the mechanism of a significant rise in lake level in Lake Victoria ~35 - 40 ka BP. Outcrops of paleo-beach deposits ~18 m above the modern day lake level indicate high water stands at ~35-40 ka BP. Based on water balance models for Lake Victoria, an increase in lake level of this magnitude could be driven by local mean annual precipitation that is significantly greater than modern. However, this is inconsistent with regional climate reconstructions. This suggests that either lake level was controlled by non-climatic factors, or that local climate in the Lake Victoria basin was different than regional patterns of climate across eastern Africa. We use oxygen and clumped isotopes of modern and fossil shells (Corbicula sp., Melanoides sp. and Bellamya unicolor) from this 18 m beach outcrop on Mfangano Island to (1) compare with modern lake water ?18O values and (2) calculate paleo-water compositions. We combine these results with calculated snail body water ?18O composition (using oxygen and clumped isotopes) of land snails (Limicoloria cf. martensiana) from Rusinga and Mfangano Islands, to study hydrological changes of Lake Victoria. We use these data to evaluate the relative importance of climate change and tectonics as mechanisms for the Late Pleistocene expansion of Lake Victoria.

Zaarur, S.; Affek, H. P.; Tryon, C.; Peppe, D. J.; Faith, J.

2013-12-01

307

LIFE CYCLE OF THE FRESHWATER SNAIL 'CAMPELOMA DECISUM' (VIVIPARIDAE) IN THE LABORATORY  

EPA Science Inventory

Campeloma decisum reared in Minnesota Lake Superior water grew consistently well when clam meat or commercial fish food was provided and a substrate of sand or mud was present. Food alone, or the substrate alone, was generally ineffective in promoting growth. Thick substrates wer...

308

Relative size influences gender role in the freshwater hermaphroditic snail, Helisoma trivolvis  

Microsoft Academic Search

Simultaneous hermaphrodites have the unique challenge of allocating their available resources to egg and sperm production and behaviorally to a male and\\/or female mating role. Models that address the influence of body size on sex allocation predict that larger individuals should allocate proportionally more resources to female than male function and that this should translate into corresponding behavioral preferences during

Cynthia G. Norton; Angela F. Johnson; Rebecca L. Mueller

2008-01-01

309

Toxic effect of two common Euphorbiales latices on the freshwater snail Lymnaea acuminata  

Microsoft Academic Search

The aqueous and serially purified latex extracts of plants Euphorbia pulcherima and Euphorbia hirta (family Euphorbiaceae) have potent molluscicidal activity. Sub-lethal doses (40 and 80% of LC50) of aqueous and partially purified latex extracts of both the plants also significantly alter the levels of total protein, total free amino acid, nucleic acid (DNA and RNA) and the activity of enzyme

Sunil Kumar Singh; R. P Yadav; Digvijay Singh; Ajay Singh

2004-01-01

310

The origin of independent and of conjoined twins in fresh-water snails  

Microsoft Academic Search

It is hoped that the observations and experiments here described will contribute to the solution of the problem of a physical basis for the origin of more than one normal adult individual from a single zygote in forms which normally produce only one individual from a single egg. The occurrence of more than one vitellus, or embryo, in eggs of

Edward D. Crabb

1931-01-01

311

CHRONIC EFFECTS OF THE HERBICIDE DIURON ON FRESHWATER CLADOCERANS,AMPHIPODS,MIDGES,MINNOWS,WORMS, AND SNAILS  

EPA Science Inventory

The chronic effects of the herbicide diuron on survival and reproduction of Daphnia pulex, and survival and growth of the amphipod Hyalella azteca, the midge Chironomus tentans, juvenile and embro/larval fathead minnows, Pimephales promelas, annelid worms, Lumbriculus variegatus,...

312

Equilibrium and kinetic studies of oxygen binding to the haemocyanin from the freshwater snail Lymnaea stagnalis.  

PubMed Central

The binding of oxygen by the haemocyanin of the gastropod Lymnaea stagnalis was studied by equilibrium and kinetic methods. The studies were performed under conditions in which the haemocyanin molecule was in the native state. Over the pH range 6.8-7.6, in the presence of 10mM-CaCl2 the haemocyanin bound O2 cooperatively. Over this pH range the haemocyanin molecule displayed a normal Bohr effect whereby the O2 affinity of the molecule decreased with a fall in the pH of the solution. The maximum slope of the Hill plot (hmax.) was 3.5, obtained at pH 7.5. An increase in the CaCl2 concentration from 5 to 20 mM at pH 6.8 resulted in a slight increase in the oxygen affinity, with hmax. remaining virtually unchanged. At constant pH and CaCl2 concentration, an increase in NaCl concentration from 0 to 50 mM resulted in a small decrease in O2 affinity, but a significant increase in the value of hmax. from 3.5 to 8.6. Temperature-jump relaxation experiments over a range of O2 concentrations produced single relaxation times. The dependence of the relaxation time on the reactant concentrations indicated a simple bimolecular binding process. The calculated association and dissociation rate constants for this process at pH 7.5 are 29.5 X 10(6) M-1 X S-1 and 49 S-1 respectively. The association rate constant kon was found to be essentially independent of pH and CaCl2 concentration. The dissociation rate constant, koff, however, increased with a decrease in the pH, but was also independent of CaCl2 concentration. These results indicate that the stability of the haemocyanin-O2 complex is determined by the dissociation rate constant. Images Fig. 4. Fig. 8. PMID:7181856

Dawson, A; Wood, E J

1982-01-01

313

UNCORRECTED Resistance in introduced populations of a freshwater snail to native  

E-print Network

, Pullman, WA, USA Introduction Introduced species experience dramatic ecological chan- ges that should lead., 2002). Introduced species can be used to address these responses to the absence of co-evolved enemies of increased competitive ability hypothesis; host­parasite interactions; introduced species; resistance

314

Behavior of technetium in freshwater environments  

SciTech Connect

In a previous study, /sup 95m/Tc, as a pertechnetate, was released to a small, experimental, freshwater pond, and the concentrations were determined in biotic and abiotic components of the pond ecosystem. A simple mathematical model was developed to predict the concentration of /sup 95m/Tc in fish and snails. Results from this study indicated that uptake through the food chain was an important source of technetium to the higher trophic levels (i.e., fish). In the current study, an experimental pond was spiked with /sup 95m/Tc in the pertechnetate form, and the concentrations of /sup 95m/Tc were measured in the lower trophic levels. Emphasis was placed on measuring the concentration of /sup 95m/Tc in zooplankton, benthic invertebrates, and the aquatic macrophyte Elodea canadensis. Fish were excluded from the pond to allow the development of a large zooplankton population. The concentration of /sup 95m/Tc in water decreased from 0.75 Bq/mL 1 h after the pond was spiked, to 0.21 Bq/mL at 20 d. Throughout the experiment, at least 98% of the /sup 95m/Tc in the water was in the dissolved fraction (0.4 ..mu..m). Zooplankton accumulated /sup 95m/Tc rapidly, having concentration factors (Bq/g sample wet wt. divided by Bq/g water) ranging from 3 at 4 h to 36 at 20 d. Concentration factors ranged from 3 to 8 for benthic insects and from 1 to 62 for the aquatic macrophyte.

Blaylock, B.G.; Frank, M.L.; Hoffman, F.O.; DeAngelis, D.L.

1984-01-01

315

Transboundary Freshwater Dispute Database  

NSDL National Science Digital Library

The database includes 150 water related treaties and 39 US compacts. The International Treaties and Compacts section is searchable by nation, basin, issues, conflict resolution mechanisms, non-water linkages, and date. US Compacts are searchable by state, basin, focus and date. For all treaties or compacts there is a summary of the agreement, the parties involved, allocations if applicable and other information pertinent to a specific agreement. There is also information available on indigenous approaches to water conflict resolution, a digitized inventory of the world's river basins with data about those basins, and a bibliography featuring publications about transboundary freshwater dispute resolution.

316

United Nations Environment Programme: Freshwater  

NSDL National Science Digital Library

This portal provides access to information on equitable and sustainable management of freshwater resources around the world. Topics include water scarcity, irrigated agriculture, water and sanitation, water quality, groundwater, transboundary water management, water and ecosystems, floods and droughts, and urban water. There are also case studies, global assessments of freshwater resources, policy documents, and information on conferences and other events.

317

The Role of Snail in EMT and Tumorigenesis  

PubMed Central

Epithelial-mesenchymal transition (EMT) is a highly conserved process in which polarized, immotile epithelial cells lose adherent and tight junctions, and become migratory mesenchymal cells. As a key transcriptional repressor of E-cadherin expression in EMT, Snail plays an important role in embryonic development and cancer progression. Emerging evidences indicate that Snail confers tumor cells with cancer stem cell-like traits, and promotes drug resistance, tumor recurrence and metastasis. In this review, we summarize recent developments underlying the regulation and functions of Snail in tumor progression, and discuss new approaches against EMT in preventing metastatic cancers. PMID:24168186

Chai, Kequn; Ying, Xuhua; Zhou, Binhua P.

2014-01-01

318

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

PubMed

Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment, they have mainly been tested separately for their effects on snail reproduction. Because large discrepancies in experimental conditions occurred in these tests, the present study aimed to compare the relative toxicity of TBT and TPT under similar laboratory conditions in the range of 0?ng Sn/L to 600?ng Sn/L. Tests were performed on the simultaneous hermaphrodite Lymnaea stagnalis, a freshwater snail in which effects of TPT were unknown. Survival, shell length, and reproduction were monitored in a 21-d semistatic test. Frequency of abnormal eggs was assessed as an additional endpoint. Triphenyltin hampered survival while TBT did not. Major effects on shell solidity and reproduction were observed for both compounds, reproductive outputs being more severely hampered by TBT than by TPT. Considering the frequency of abnormal eggs allowed increasing test sensitivity, because snail responses to TBT could be detected at concentrations as low as 19?ng Sn/L. However, the putative mode of action of the 2 compounds could not be deduced from the structure of the molecules or from the response of apical endpoints. Sensitivity of L. stagnalis to TBT and TPT was compared with the sensitivity of prosobranch mollusks with different habitats and different reproductive strategies. PMID:23450754

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

2013-07-01

319

Assessment of the potential of competitor snails and African catfish (Clarias gariepinus) as biocontrol agents against snail hosts transmitting schistosomiasis.  

PubMed

The objective of this study was to assess the potential of the snails Physa acuta and Melanoides tuberculata and the African catfish Clarias gariepinus as biological control agents against the Schistosoma mansoni intermediate host Biomphalaria pfeifferi under laboratory conditions. Groups of five target and five competitor snails were raised together in experimental aquaria and same number in separate aquaria as controls. Shell size, number of eggs and mortality rate were recorded for twelve consecutive weeks. The stocking density for C. gariepinus was one fish per aquarium. Fish were provided with adequate or inadequate supplementary food and fifteen B. pfeifferi were added to each aquarium. The snails and their eggs were counted daily. Significant differences in shell growth and fecundity were noted between B. pfeifferi and M. tuberculata. Physa acuta was noted to be voracious in food consumption. Snail consumption was faster by fish provided with inadequate supplementary food. Based on the present findings, it is suggested that the two competitor snails and African catfish could be used as biological control agents against B. pfeifferi. Nevertheless, the susceptibility of the competitor snails to other trematodes in Ethiopia must first be ruled out before introducing these snails into new habitats. Follow-up field observation and rigorous laboratory studies remain areas for further research. PMID:18582914

Gashaw, Fikru; Erko, Berhanu; Teklehaymanot, Tilahun; Habtesellasie, Redeat

2008-08-01

320

Laboratory experiments on snail predation by Sargochromis codringtoni, a candidate for biological control of the snails that transmit schistosomiasis.  

PubMed

The potential efficacy of Sargochromis codringtoni, a species of cichlid fish, in the biological control of snails carrying the Schistosoma spp. infecting man has long been recognized. A laboratory study to produce much-needed data on the malacophagous characteristics of this fish was conducted, to see if field studies on its possible role as a biological agent for snail control in Zimbabwe were likely to be worthwhile. The fish can consume large numbers of snails within a short period: a single fish, provided with trout pellets as an alternative food, not only chose to eat the snails but also consumed > 800 within 3 weeks. Addition of macrophytes to the aquaria used appeared to offer the snails no protection from predation. For fish measuring 15-18 cm in length, there was no size preference among snails measuring up to 12 mm in shell height nor was any species preference observed in experiments involving Bulinus globosus, B. tropicus and Melanoides tuberculata. The fish crushed B. globosus which were > 3.0 mm in shell height in their pharynges but swallowed smaller snails of this species whole. Before field trials are conducted, further laboratory studies, in which field conditions are simulated, should be carried out. PMID:9093434

Chimbari, M J; Madsen, H; Ndamba, J

1997-01-01

321

Taxonomy: A Precursor to Understanding Ecological Interactions among Schistosomes, Snail Hosts, and Snail-Eating Fishes  

Microsoft Academic Search

We have observed a dramatic decrease in the abundance of snail-eating fishes and an increase in the prevalence of schistosomiasis among village residents and expatriate tourists at Lake Malawi, Africa, over the past two decades. We hypothesized that these observations were linked by a cause-and-effect relationship and that the observed decrease in fish molluscivores permitted an increase in the abundance

Jay Richard Stauffer Jr; Henry Madsen; Adrianus Konings; Paul Bloch; Cecilia Paola Ferreri; Jeremy Likongwe; Kenneth R. McKaye; Kristin E. Black

2007-01-01

322

Analysis of a cone snail’s killer cocktail – The milked venom of Conus geographus?  

PubMed Central

Snails can kill” is a statement that receives much disbelief. Yet the venom from Conus geographus, as delivered by a disposable hypodermic-like needle, has indeed killed many unsuspecting human victims. Our understanding of their milked venom the essence of these fatalities, is in itself non-existent. Here, we present the molecular mass analysis of the milked venom of C. geographus, providing the first insight into the composition of its deadly cocktail. PMID:22884604

Bingham, Jon-Paul; Baker, Margaret R.; Chun, Joycelyn B.

2013-01-01

323

METHODS FOR EXCLUDING SLUGS AND SNAILS ON EXPORTED HORTICULTURAL COMMODITIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Increasingly, slugs and snails (mollusks) are recognized as important quarantine pests threatening agriculture, export markets and the environment. This increased awareness results from the rapid spread of damaging species concurrent with higher levels of international trade of horticultural commodi...

324

Impairment of DNA in a Freshwater Gastropod (Lymnea luteola L.) After Exposure to Titanium Dioxide Nanoparticles.  

PubMed

The apoptotic and genotoxic potential of titanium dioxide nanoparticles (TiO2NPs) were evaluated in hemocyte cells of freshwater snail Lymnea luteola L. Before evaluation of the toxic potential, mean size of the TiO2NPs was determined using a transmission electron microscopy and dynamic light scattering. In this study, L. luteola were exposed to different concentrations of TiO2NPs (28, 56, and 84 ?g/ml) over 96 h. Induction of oxidative stress in hemolymph was observed by a decrease in reduced glutathione and glutathione-S-transferase levels at different concentration of TiO2NPs and, in contrast, an increase in malondialdehyde and reactive oxygen species levels. Catalase activity was decreased at lower concentrations but increased at greater concentration of TiO2NPs. The extent of DNA fragmentation occurring in L. luteola due to ecotoxic impact TiO2NPs was further substantiated by alkaline single-cell gel electrophoresis assay and expressed in terms of % tail DNA and olive tail moment. The alkaline single-cell gel electrophoresis assay for L. luteola clearly shown relatively greater DNA damage at the highest concentration of TiO2NPs.The results indicate that the interaction of TiO2NPs with snail influences toxicity, which is mediated by oxidative stress according dose and in a time-dependent manner. The results of this study showed the importance of a multibiomarker approach for assessing the injurious effects of TiO2NPs to freshwater snail L. luteola, which may be vulnerable due to the continuous discharge of TiO2NPs into the aquatic ecosystems. The measurement of DNA integrity in L. luteola thus provides an early warning signal of contamination of the aquatic ecosystem by TiO2NPs. PMID:25661047

Ali, Daoud; Ali, Huma; Alarifi, Saud; Kumar, Sudhir; Serajuddin, M; Mashih, Agha P; Ahmed, Mukhtar; Khan, Mujeeb; Adil, Syed Farooq; Shaik, M R; Ansari, Anees A

2015-04-01

325

Effect of Molasses on Golden Apple Snail Silage Production  

Microsoft Academic Search

The production of golden apple snail silage was carried out by fermenting the minced golden apple snail with locally screened lactic acid bacteria; L1\\/2, at ambient temperature using molasses as the carbon source for bacterial growth. The pH value rapidly decreased to 5.0 after 3 days of fermentation, allowing an increase of free amino acid that was released from protein

Kittipong Rattanaporn; Soykaew Ieng-ubol; Watcharee Songsi-oon

326

Sequestration of lichen compounds by three species of terrestrial snails  

Microsoft Academic Search

Three species of lichen-grazing snails,Balea perversa, Chondria clienta, andHelicigona lapicida, all from the Swedish island of Öland, were found to sequester lichen compounds when feeding on the crustous lichen speciesAspicila calcarea, Caloplaca flavovirescens, Lecanora muralis, Physcia adscendens, Tephromela atra, andXanthoria parietina. The lichen compounds detected in the soft bodies of the snail species analyzed included the anthraquinone parietin, the depside

Sonja Hesbacher; Bruno Baur; Anette Baur; Peter Proksch

1995-01-01

327

Transboundary Freshwater Dispute Database  

NSDL National Science Digital Library

Created and maintained by Dr. Aaron T. Wolf of the Department of Geosciences at Oregon State University, this site is designed to help researchers and students explore water disputes and negotiations in the 20th century. To that end, it offers a searchable database containing the summaries and full text of 150 international water-related treaties and another similar database of 39 interstate compacts within the US. Treaties within the databases may be selected by nation or state, main and treaty basins, focus, and beginning and ending dates. Additional resources include a digitized inventory of international watersheds. In the future, Wolf plans to add descriptions of indigenous/ traditional methods for the resolution of water disputes, news files and bibliographic entries of acute water conflicts, and an annotated bibliography of the state of the art of Transboundary Freshwater Dispute Resolution.

328

The Decline of Freshwater Ecosystems  

NSDL National Science Digital Library

This article discusses the risks that freshwater ecosystems face and how species nearby are affected by dams, dredging, and channelization of streams. It points out that even though freshwater ecosystems are limited in extent, covering about 1 percent of the Earth's surface, they are highly diverse and contain a disproportionally large number of the world's species. Statistics are given to illustrate the increase in waterways that have been altered for navigation. Some actions that are being taken to reduce threats to freshwater ecosystems are also mentioned.

1999-01-01

329

Antioxidant and molecular chaperone defences during estivation and arousal in the South American apple snail Pomacea canaliculata.  

PubMed

The invasive Pomacea canaliculata estivates during periods of drought and should cope with harmful effects of reoxygenation during arousal. We studied thiobarbituric acid reactive substances (TBARS), enzymatic (superoxide dismutase, SOD and catalase, CAT) and non-enzymatic antioxidants (uric acid and reduced glutathione), and heat shock protein expression (Hsc70, Hsp70 and Hsp90) in (1) active control snails, (2) snails after 45 days of estivation, and (3) aroused snails 20 min and (4) 24 h after water exposure, in midgut gland, kidney and foot. Both kidney and foot (but not the midgut gland) showed a TBARS increase during estivation and a decrease after arousal. Tissue SOD and CAT did not change in any experimental groups. Uric acid increased during estivation in all tissues, and it decreased after arousal in the kidney. Allantoin, the oxidation product of uric acid, remained constant in the midgut gland but it decreased in the kidney until 20 min after arousal; however, allantoin levels rose in both kidney and foot 24 h after arousal. Reduced glutathione decreased during estivation and arousal, in both midgut gland and kidney, and it remained constant in the foot. Hsc70 and Hsp70 kidney levels were stable during the activity-estivation cycle and Hsp90 expression decreases during estivation and recovers in the early arousal. In foot, the expression of Hsp70 and Hsp90 was high during activity and estivation periods and disminished after arousal. Results indicate that a panoply of antioxidant and molecular chaperone defences may be involved during the activity-estivation cycle in this freshwater gastropod. PMID:23077161

Giraud-Billoud, Maximiliano; Vega, Israel A; Tosi, Martín E Rinaldi; Abud, María A; Calderón, María L; Castro-Vazquez, Alfredo

2013-02-15

330

Rapid spread of an invasive snail in South America: the giant African snail, Achatina fulica , in Brasil  

Microsoft Academic Search

Beginning around 1800, but primarily since the early and mid-twentieth century, the giant African snail, Achatina (Lissachatina) fulica Bowdich, 1822, has been introduced throughout the tropics and subtropics and has been considered the most important snail\\u000a pest in these regions. In Brasil, specimens probably brought from Indonesia were introduced into the state of Paran? in the\\u000a 1980s for commercial purposes

Silvana C. Thiengo; Fábio André Faraco; Norma C. Salgado; Robert H. Cowie; Monica A. Fernandez

2007-01-01

331

Toxicity of snail attractant pellets containing eugenol with respect to abiotic factors against the vector snail Lymnaea acuminata  

Microsoft Academic Search

Every month during the year 2010–2011, the 24 to 96 h LC50 values of molluscicide eugenol, in snail attractant pellets (SAP), were determined against a snail Lymnaea acuminata, with concomitant determination of levels of temperature, pH, dissolved oxygen, carbon dioxide, and electrical conductivity in test water. On the basis of a 24 h toxicity assay, it was noted that LC50 values 2.55,

Pooja Agrahari; V. K. Singh; D. K. Singh

2012-01-01

332

The geographic mosaic of sex and infection in lake populations of a New Zealand snail at multiple spatial scales.  

PubMed

Understanding how sexual and asexual forms of the same species coexist is a challenge for evolutionary biology. The Red Queen hypothesis predicts that sex is favored by parasite-mediated selection against common asexual genotypes, leading to the coexistence of sexual and asexual hosts. In a geographic mosaic, where the risk of infection varies in space, the theory also predicts that sexual reproduction would be positively correlated with disease prevalence. We tested this hypothesis in lake populations of a New Zealand freshwater snail, Potamopyrgus antipodarum, by comparing pairwise difference matrices for infection frequency and male frequency using partial Mantel tests. We conducted the test at three spatial scales: among lakes on the South Island, among depths within an intensively sampled lake (Lake Alexandrina), and within depths at Lake Alexandrina. We found that the difference in infection risk and the difference in the proportion of sexual snails were significantly and positively correlated at all spatial scales. Our results thus suggest that parasite-mediated selection contributes to the long-term coexistence of sexual and asexual individuals in coevolutionary hotspots, and that the "warmth" of hotspots can vary on small spatial scales. PMID:24021401

Vergara, Daniela; Lively, Curtis M; King, Kayla C; Jokela, Jukka

2013-10-01

333

Freshwater microcosms-based assessment of eco-toxicological effects of a chemical effluent from the Pilcam industry in Cameroon.  

PubMed

We studied the acute toxicity of a raw effluent from a battery manufacturing plant (Pilcam) in Douala, Cameroon, to a freshwater fish (Oreochromis niloticus), and subsequently evaluated its sub-acute effects on water quality and the biota in freshwater microscosms. The acute toxicity test was based on 96 hrs static renewal bioassays that resulted in 96-h LC50 and LC90 values of 16 and 20.7% (v/v), respectively. The sub-acute experiments were conducted by exposing several species of aquatic organisms (plankton, macroinvertebrates and mollusks) to lower effluent concentrations [1.6%, 8.0%, 16% (v/v)] for six weeks, and monitoring their survival rates, as well as the physical and chemical characteristics of water. These concentrations were based on 10%, 50%, and 100% of the 96 h - median lethal concentrations (LC50) of the effluent to the freshwater fish, Oreochromis niloticus. Significant effects on functional parameters, such as, chlorophyll-a and total protein could not be demonstrated. However, the activity of alkaline phosphatase was significantly inhibited at all concentrations tested. Phytoplankton, zooplankton, macro-invertebrate communities and snails were negatively affected by the effluent application at concentrations ? 8% (v/v), with chlorophyta, ciliates, ostracoda, annelida, planaria and snails being the most sensitive groups. The snails were eliminated after 24 h exposure from microcosms treated with effluent at concentration ? 8% (v/v). Effluent exposure also caused significant effects on water quality parameters (DO, pH, hardness, conductivity, color, turbidity, ammonia) in general at concentrations ? 8% (v/v). Temperature and alkalinity were not significantly affected. Overall, data from this research indicate that a dilution of the Pilcam effluent down to 1.6% does not provide protection against chronic toxicity to aquatic organisms. Further studies are needed to determine the no observable adverse effect level (NOAEL), as well as a chronic reference concentration for this effluent. PMID:16696186

Monkiedje, A; Njinel, T; Meyabeme Elono, A L; Zebaze, S H; Kemka, N; Tchounwou, P B; Djomo, J E

2004-09-01

334

A conserved role for Snail as a potentiator of active transcription  

PubMed Central

The transcription factors of the Snail family are key regulators of epithelial–mesenchymal transitions, cell morphogenesis, and tumor metastasis. Since its discovery in Drosophila ?25 years ago, Snail has been extensively studied for its role as a transcriptional repressor. Here we demonstrate that Drosophila Snail can positively modulate transcriptional activation. By combining information on in vivo occupancy with expression profiling of hand-selected, staged snail mutant embryos, we identified 106 genes that are potentially directly regulated by Snail during mesoderm development. In addition to the expected Snail-repressed genes, almost 50% of Snail targets showed an unanticipated activation. The majority of “Snail-activated” genes have enhancer elements cobound by Twist and are expressed in the mesoderm at the stages of Snail occupancy. Snail can potentiate Twist-mediated enhancer activation in vitro and is essential for enhancer activity in vivo. Using a machine learning approach, we show that differentially enriched motifs are sufficient to predict Snail's regulatory response. In silico mutagenesis revealed a likely causative motif, which we demonstrate is essential for enhancer activation. Taken together, these data indicate that Snail can potentiate enhancer activation by collaborating with different activators, providing a new mechanism by which Snail regulates development. PMID:24402316

Rembold, Martina; Ciglar, Lucia; Yáñez-Cuna, J. Omar; Zinzen, Robert P.; Girardot, Charles; Jain, Ankit; Welte, Michael A.; Stark, Alexander; Leptin, Maria; Furlong, Eileen E.M.

2014-01-01

335

BIODIVERSITY Conservation biogeography of freshwater  

E-print Network

and Emili Garci´a-Berthou5 INTRODUCTION Early naturalists Alfred Russel Wallace and Charles Darwin inspired implications of their distributions are far reaching (Darwin, 1839; Wallace, 1876). Freshwater fishes exemplify

García-Berthou, Emili

336

Freshwater systems threatened, report charges  

NASA Astrophysics Data System (ADS)

U.S. freshwater systems, including lakes, rivers, and wetlands, may face serious threats from temperature increases and weather pattern variations projected for the coming century according to a 29 January report by the Pew Center on Global Climate Change.

Showstack, Randy

337

Bioaccumulation and distribution of /sup 95m/Tc in an experimental freshwater pond  

SciTech Connect

An acute release of /sup 95m/Tc was made to a small experimental freshwater pond to determine the behavior of technetium in a freshwater ecosystem. The objectives of the study were (1) to determine the distribution of /sup 95m/Tc in the components of the ecosystem and (2) to determine the concentration in freshwater biota. Prior to the release of /sup 95m/Tc, the pond was stocked with aquatic macrophytes, fish, and invertebrates. All components of the pond were sampled for a period of 37 d. Analyses of filtered and unfiltered water samples showed that /sup 95m/Tc did not sorb significantly to particulates suspended in the water but remained dissolved. Sediments accumulated /sup 95m/Tc slowly as the experiment progressed. In the biota, periphyton accumulated /sup 95m/Tc rapidly, reaching the highest concentration (3482 dpm/g dry wt) 4 h after the release and maintaining a relatively high concentration throughout the experiment. Fish and invertebrates accumulated /sup 95m/Tc gradually. Elimination studies and tissue analyses showed that a large percentage of the body burden was in the digestive system of all fish, suggesting that fish were accumulating /sup 95m/Tc through the food chain. Biological half-lives determined from elimination studies for carp (Cyprinus carpio), mosquitofish (Gambusia affinis), and snails (Helisoma sp.) were 2.5, 4.3, and 21.3 d, respectively. Calculated concentration factors for the same species were 11 for carp, 75 for mosquito fish, and 121 for snails. The estimated size of the biomass components in the ecosystem in descending order were: periphyton, macrophytes, invertebrates, fish, and algae. Based on biomass estimates and concentrations of the /sup 95m/Tc in the aquatic biota, approximately 1% of the /sup 95m/Tc accumulated in the biota.

Blaylock, B.G.; Frank, M.L.

1981-01-01

338

Functional Changes in the Snail Statocyst System Elicited by Microgravity  

PubMed Central

Background The mollusk statocyst is a mechanosensing organ detecting the animal's orientation with respect to gravity. This system has clear similarities to its vertebrate counterparts: a weight-lending mass, an epithelial layer containing small supporting cells and the large sensory hair cells, and an output eliciting compensatory body reflexes to perturbations. Methodology/Principal Findings In terrestrial gastropod snail we studied the impact of 16- (Foton M-2) and 12-day (Foton M-3) exposure to microgravity in unmanned orbital missions on: (i) the whole animal behavior (Helix lucorum L.), (ii) the statoreceptor responses to tilt in an isolated neural preparation (Helix lucorum L.), and (iii) the differential expression of the Helix pedal peptide (HPep) and the tetrapeptide FMRFamide genes in neural structures (Helix aspersa L.). Experiments were performed 13–42 hours after return to Earth. Latency of body re-orientation to sudden 90° head-down pitch was significantly reduced in postflight snails indicating an enhanced negative gravitaxis response. Statoreceptor responses to tilt in postflight snails were independent of motion direction, in contrast to a directional preference observed in control animals. Positive relation between tilt velocity and firing rate was observed in both control and postflight snails, but the response magnitude was significantly larger in postflight snails indicating an enhanced sensitivity to acceleration. A significant increase in mRNA expression of the gene encoding HPep, a peptide linked to ciliary beating, in statoreceptors was observed in postflight snails; no differential expression of the gene encoding FMRFamide, a possible neurotransmission modulator, was observed. Conclusions/Significance Upregulation of statocyst function in snails following microgravity exposure parallels that observed in vertebrates suggesting fundamental principles underlie gravi-sensing and the organism's ability to adapt to gravity changes. This simple animal model offers the possibility to describe general subcellular mechanisms of nervous system's response to conditions on Earth and in space. PMID:21479267

Balaban, Pavel M.; Malyshev, Aleksey Y.; Ierusalimsky, Victor N.; Aseyev, Nikolay; Korshunova, Tania A.; Bravarenko, Natasha I.; Lemak, M. S.; Roshchin, Matvey; Zakharov, Igor S.; Popova, Yekaterina; Boyle, Richard

2011-01-01

339

50 CFR 17.45 - Special rules-snails and clams. [Reserved  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Special rules-snails and clams. [Reserved] 17.45 Section... Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE...Wildlife § 17.45 Special rules—snails and clams....

2010-10-01

340

50 CFR 17.45 - Special rules-snails and clams. [Reserved  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Special rules-snails and clams. [Reserved] 17.45 Section... Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE...Wildlife § 17.45 Special rules—snails and clams....

2012-10-01

341

50 CFR 17.45 - Special rules-snails and clams. [Reserved  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Special rules-snails and clams. [Reserved] 17.45 Section... Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE...Wildlife § 17.45 Special rules—snails and clams....

2011-10-01

342

50 CFR 17.45 - Special rules-snails and clams. [Reserved  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Special rules-snails and clams. [Reserved] 17.45 Section... Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE...Wildlife § 17.45 Special rules—snails and clams....

2013-10-01

343

50 CFR 17.45 - Special rules-snails and clams. [Reserved  

Code of Federal Regulations, 2014 CFR

...2014-10-01 false Special rules-snails and clams. [Reserved] 17.45 Section... Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE...Wildlife § 17.45 Special rules—snails and clams....

2014-10-01

344

Fibrinogen-bearing protein genes in the snail Biomphalaria glabrata: characterization of two novel genes and expression studies during ontogenesis and trematode infection  

PubMed Central

All fibrinogen (FBG)-bearing proteins documented to date in the freshwater snail Biomphalaria glabrata, the intermediate host of the human blood fluke Schistosoma mansoni, possess the same molecular structure; one or two immunoglobin superfamily (IgSF) domains at the N-terminus and a FBG domain at the C-terminus (named as FBG-related protein (FREP)). Here we report two novel genes that encode FBG-bearing proteins from B. glabrata. Different from all known FREPs, the first gene encodes a protein (657 amino acids (aa)) composed of a long N-terminal region with no sequence homology to any known protein, a middle epidermal growth factor (EGF) repeat region and a C-terminal FBG domain, designated FBG-related molecule (FReM). A differential expression at 2 days post exposure (dpe) to the trematode S. mansoni or Echinostoma paraensei has been found in the S. mansoni susceptible M line and resistant BS-90 snail strains. The second gene is a new member of the FREP family, designated FREP14, which encodes a 399 aa putative secreted protein. FREP14 is different from known FREPs in that it is encoded by a single locus and is not upregulated in early or late stage S. mansoni exposure, but is upregulated in late stage E. paraensei infection. Furthermore, gene expression during the snail’s ontogenesis and at a late stage of trematode-infection (52 dpe) has been investigated in the two newly-identified genes (FReM and FREP14) described in this paper and five representative members of known FREPs (FREPs 2, 3, 4, 12, and 13). A variety of expression patterns were observed, suggestive of functional diversity among the members of FBG-bearing proteins. Our findings further broaden our understanding of the diversity and function of the FBG-bearing protein encoded genes in B. glabrata. PMID:18417215

Zhang, Si-Ming; Nian, Hong; Zeng, Yong; DeJong, Randall J.

2008-01-01

345

Differential regulation of Snail by hypoxia and hyperglycemia in human proximal tubule cells  

Microsoft Academic Search

The centrality of the transcriptional regulator Snail in epithelial-to-mesenchymal transformation (EMT), known to occur in models of diabetic nephropathy, has not been established. Transforming growth factor beta-1 (TGF?1) is induced in diabetic nephropathy and induces both Snail and EMT. Hypoxia inducible factors (HIFs) are known to induce Snail, independent of TGF?1. Notch induction is integral to Snail induction and EMT

Siska Sumual; Sonia Saad; Owen Tang; Rachel Yong; Stella McGinn; Xin-Ming Chen; Carol A. Pollock

2010-01-01

346

Population structure and coil dimorphism in a tropical land snail.  

PubMed

Tree snails of the subgenus Amphidromus s. str. are unusual because of the chiral dimorphism that exists in many species, with clockwise (dextrally) and counter-clockwise (sinistrally) coiled individuals co-occurring in the same population. Given that mating in snails is normally impeded when the two partners have opposite coil, positive frequency-dependent selection should prevent such dimorphism from persisting. We test the hypothesis that a strong population structure with little movement between tree-based demes may result in the fixation of coiling morphs at a very small spatial scale, but apparent dimorphism at all larger scales. To do so, we describe the spatial structure in a Malaysian population of A. inversus (Müller, 1774) with 36% dextrals. We marked almost 700 juvenile and adult snails in a piece of forest consisting of 92 separate trees, and recorded dispersal and the proportions of dextrals and sinistrals in all trees over a 7-day period. We observed frequent movement between trees (155 events), and found that no trees had snail populations with proportions of dextrals and sinistrals that were significantly different from random. Upon recapture 1 year later, almost two-thirds of the snails had moved away from their original tree. We conclude that population structure alone cannot stabilise the coil dimorphism in Amphidromus. PMID:16077741

Schilthuizen, M; Scott, B J; Cabanban, A S; Craze, P G

2005-09-01

347

Prey selection by molluscivorous cichlids foraging on a schistosomiasis vector snail, Biomphalaria glabrata  

Microsoft Academic Search

This paper considers prey size selection by four molluscivorous cichlids feeding on the intermediate host snail of Schistosoma parasites, Biomphalaria glabrata. Haplochromis ishmaeli obtains its prey by crushing the snails between the pharyngeal jaws, whereas H. xenognathus, H. sauvagei and Macropleurodus bicolor apply both pharyngeal crushing and oral shelling. The fishes crushed significantly more snails with the highest reward in

R. Slootweg

1987-01-01

348

AN EVALUATION OF CHEMICAL, BIOLOGICAL, AND COMBINED CHEMICAL-BIOLOGICAL APROACHES FOR CONTROLLING SNAILS IN AQUACULTURE  

E-print Network

the marketability of food fish. Aquatic snails are intermediate hosts in the trematode lifecycle and are commonly. Ponds stocked with sunfish at 494 fish/ha had snail densities significantly (P 0.05) lower than control SNAILS IN AQUACULTURE PONDS by Matthew R. Noatch B.S., Missouri State University, 2007 A Thesis Submitted

349

Fluorescent pigment distinguishes between sibling snail species.  

PubMed

Traditional taxonomy of shell-bearing molluscs does not generally use soft-body coloration. However, the land snails Bradybaena pellucida and B. similaris have been distinguished only on the basis of the color of the soft-body visible through the shell. Thus, the taxonomic status of the two species has traditionally been questionable. We found that dense spots of pigments embedded in the dorsal mantle are responsible for the yellow coloration of B. pellucida . Similar spots in B. similaris are white and less densely aggregated in whorls further from the apex, and the brown color of the hepatopancreas is visible through the shell. The yellow pigments of B. pellucida seep out with mucus from the body in natural and laboratory conditions. The two species became externally indistinguishable after 30 days of laboratory feeding, because the yellow spots disappeared in B. pellucida and the color of the hepatopancreas changed from dark brown to pale brown in both species. Irradiation with ultraviolet A demonstrated that the yellow pigment of B. pellucida fluoresces. Adult specimens of the two species were distinct in penial microsculpture, with F(1) hybrids intermediate in form. Populations of the two species differed significantly in allelic frequencies at four allozyme loci. Therefore, B. pellucida and B. similaris are morphologically and genetically distinct. The fluorescent yellow pigment distinguishes B. pellucida from B. similaris under natural conditions despite its environmental dependence. PMID:19267648

Seki, Keiichi; Wiwegweaw, Amporn; Asami, Takahiro

2008-12-01

350

A snail with unbiased population sex ratios but highly biased brood sex ratios.  

PubMed Central

Extraordinary sex ratio patterns and the underlying sex-determining mechanisms in various organisms are worth investigating, particularly because they shed light on adaptive sex-ratio adjustment. Here, we report an extremely large variation in the brood sex ratio in the freshwater snail, Pomacea canaliculata. In eight rearing series originating from three wild populations, sex ratios were highly variable among broods, ranging continuously from almost exclusively males to almost exclusively females. However, sex ratios were similar between broods from the same mating pair, indicating that sex ratio is a family trait. Irrespective of the large variations, the average sex ratios in all rearing series were not significantly different from 0.5. We argue that Fisher's adaptive sex-ratio theory can explain the equal average sex ratios, and the results, in turn, directly support Fisher's theory. Polyfactorial sex determination (in which sex is determined by three or more genetic factors) is suggested as the most likely mechanism producing the variable brood sex ratio. PMID:12614578

Yusa, Yoichi; Suzuki, Yoshito

2003-01-01

351

Pleistocene glaciation is implicated in the phylogeographical structure of Potamopyrgus antipodarum, a New Zealand snail.  

PubMed

Pleistocene glaciation has been identified as an important factor shaping present-day patterns of phylogeographical structure in a diverse array of taxa. The purpose of this study was to use mitochondrial sequence data to address whether Pleistocene glaciation is also a major determinant of phylogeographical patterns in Potamopyrgus antipodarum, a freshwater snail native to New Zealand. We found that haplotypes were separated by no more than 3.7% sequence divergence, and major genetic divisions tended to occur on a north-south axis. These data fit the predictions of the hypothesis that isolation of P. antipodarum in glacial refugia at the northern and southern tip of the South Island of New Zealand during the Pleistocene glaciation underlies the present-day phylogeographical structure. Because sexual P. antipodarum occasionally produce asexual offspring, we also used these data to show that the appearance of asexuality is not phylogeographically constrained. This means that the maintenance of sex in P. antipodarum cannot be wholly due to limited contact between sexual and asexual lineages and must instead be linked to a selective advantage of sexual reproduction. PMID:15367122

Neiman, Maurine; Lively, Curtis M

2004-10-01

352

Interference with Fasciola hepatica snail finding by various aquatic organisms.  

PubMed

Previous studies using radioactive miracidia have shown that a number of non-host snails and bivalves, interposed as 'decoys' in linear test channels, may interfere with the capacity of Fasciola hepatica miracidia to infect Lymnaea truncatula. Applying similar experimental principles, the role of several other potential interferents have been analysed in the present study. Daphnia pulex (Cladocera) and larvae of Corethra sp. (Diptera) exercised significant interfering effects by protecting 'target' snails from infection. Evidence suggested that this effect was a result of their normal predatory behaviour. Other organisms including Herpobdella testacea and Helobdella stagnalis (Hirudinea), Acellus aquaticus (Isopoda), Planaria lugubris (Turbellaria) and L. truncatula egg clusters failed to interfere with miracidial host-finding. Nor did P. lugubris and L. truncatula 'conditioned water' interfere with the capacity of the miracidia to infect their host snail. PMID:876683

Christensen, N O; Nansen, P; Frandsen, F

1977-06-01

353

MTA3 regulates CGB5 and Snail genes in trophoblast  

SciTech Connect

Highlights: •Impaired MTA3, raised CGB5 and Snail expression are associated with preeclampsia. •Knock-down of MTA3 causes up-regulation of CGB5 and Snail genes in BeWo cells. •MTA3 occupies CGB5 and Snail gene promoters in BeWo cells. -- Abstract: Secreted by the placental trophoblast, human chorionic gonadotropin (hCG) is an important hormone during pregnancy and is required for the maintenance of pregnancy. Previous studies have shown that dys-regulation of hCG expression is associated with preeclampsia. However, the exact relationship between altered hCG levels and development of preeclampsia is unknown. Metastasis associated protein 3 (MTA3), a chromatin remodeling protein, is abundantly expressed in the placental trophoblasts, but its function is unknown. In breast cancer, MTA3 has been shown to repress the expression of Snail and cell migration. However, whether MTA3 acts similarly in the trophoblast has not been investigated. In the present study, we examined the role of MTA3 in regulating the hCG ?-subunit gene (gene name: CGB5) and Snail expression in the trophoblast cell line, BeWo, as well as its relevance to the high hCG expression levels seen in preeclampsia. First, we investigated MTA3 expression in preeclamptic placenta as compared to normal control placenta via gene expression microarray and qRT-PCR and found that MTA3 was significantly down-regulated, whereas both CGB5 and Snail were up-regulated in preeclamptic placenta. Secondly, we knocked down MTA3 gene in trophoblast cell line BeWo and found Snail and hCG were both up-regulated, suggesting that MTA3 represses Snail and hCG gene expression in trophoblasts. Next, we cloned the CGB5 and Snail promoters into the pGL3-basic vector individually and found that silencing of MTA3 by siRNA resulted in an increase of both CGB5 and Snail promoter activities. To confirm that this MTA3 inhibition is a direct effect, we performed a chromatin immune-precipitation (ChIP) assay and found that MTA3 occupied the proximal promoter regions of both Snail and hCG within BeWo cells. Furthermore, we examined MTA3 expression in placental trophoblast by immunohistochemistry and found that MTA3 expression was higher in villous cytotrophoblasts versus syncytiotrophoblasts, which supports an inverse association of MTA3 with hCG expression. Lastly, using the well-characterized trophoblast fusion model, we examined MTA3 and hCG levels in forskolin-treated BeWo cells and found that MTA3 down-regulation was accompanied by an up-regulation of hCG. These data further suggest that MTA3 is repressing placental hCG expression. In summary, MTA3 plays a critical role in repressing hCG and Snail in placenta trophoblast and its deregulation is associated with preeclampsia.

Chen, Ying [Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, Grand Rapids, MI 49503 (United States)] [Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, Grand Rapids, MI 49503 (United States); Miyazaki, Jun [Department of Obstetrics and Gynecology, Fujita Health University School of Medicine, Fujita Health University, Toyoake (Japan) [Department of Obstetrics and Gynecology, Fujita Health University School of Medicine, Fujita Health University, Toyoake (Japan); Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake (Japan); Nishizawa, Haruki [Department of Obstetrics and Gynecology, Fujita Health University School of Medicine, Fujita Health University, Toyoake (Japan)] [Department of Obstetrics and Gynecology, Fujita Health University School of Medicine, Fujita Health University, Toyoake (Japan); Kurahashi, Hiroki [Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake (Japan)] [Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake (Japan); Leach, Richard, E-mail: Richard.Leach@hc.msu.edu [Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, Grand Rapids, MI 49503 (United States) [Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, Grand Rapids, MI 49503 (United States); Department of Obstetrics, Gynecology and Women’s Health, Spectrum Health Medical Group, Grand Rapids, MI 49503 (United States); Wang, Kai, E-mail: Kai.Wang@hc.msu.edu [Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, Grand Rapids, MI 49503 (United States)] [Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, Grand Rapids, MI 49503 (United States)

2013-04-19

354

The relationship between genetic variability and the susceptibility of Biomphalaria alexandrina snails to Schistosoma mansoni infection.  

PubMed

In the present study, Biomphalaria snails collected from five Egyptian governorates (Giza, Fayoum, Kafr El-Sheikh, Ismailia and Damietta), as well as reference control Biomphalaria alexandrina snails from the Schistosome Biological Supply Center (SBSC) (Theodor Bilharz Research Institute, Egypt), were subjected to species-specific polymerase chain reaction (PCR) assays to identify the collected species. All of the collected snails were found to be B. alexandrina and there was no evidence of the presence of Biomphalaria glabrata. Randomly amplified polymorphic DNA (RAPD)-PCR assays showed different fingerprints with varying numbers of bands for the first generation (F?) of B. alexandrina snail populations (SBSC, Giza, Fayoum, Kafr El-Sheikh, Ismailia and Damietta). The primer OPA-1 produced the highest level of polymorphism and amplified the greatest number of specific bands. The estimated similarity coefficients among the B. alexandrina populations based on the RAPD-PCR profiles ranged from 0.56 (between SBSC and Ismailia snails) to 0.72 (between Ismailia and Kafr El-Sheikh snails). Experimental infection of the F? of progeny from the collected snails with Schistosoma mansoni (SBSC strain) showed variable susceptibility rates ranging from 15% in the Fayoum snail group to 50.3% in SBSC snails. A negative correlation was observed between the infection rates in the different snail groups and the distances separating their corresponding governorates from the parasite source. The infection rates of the snail groups and their similarity coefficients with SBSC B. alexandrina snails were positively correlated. The variations in the rates of infection of different B. alexandrina groups with S. mansoni, as well as the differences in the similarity coefficients among these snails, are dependent not only on the geographical distribution of the snails and the parasite, but also on the genetic variability of the snails. Introduction of this variability into endemic areas may reduce the ability of the parasite to infect local hosts and consequently reduce schistosomiasis epidemiology. PMID:22510827

Mohamed, Azza H; El-Din, Ahmed T Sharaf; Mohamed, Ahmed M; Habib, Mohamed R

2012-05-01

355

Movements of florida apple snails in relation to water levels and drying events  

USGS Publications Warehouse

Florida apple snails (Pomacea Paludosa) apparently have only a limited tolerance to wetland drying events (although little direct evidence exists), but their populations routinely face dry downs under natural and managed water regimes. In this paper, we address speculation that apple snails respond to decreasing water levels and potential drying events by moving toward refugia that remain inundated. We monitored the movements of apple snails in central Florida, USA during drying events at the Blue Cypress Marsh (BC) and at Lake Kissimmee (LK). We monitored the weekly movements of 47 BC snails and 31 LK snails using radio-telemetry. Snails tended to stop moving when water depths were 10 cm. Snails moved along the greatest positive depth gradient (i.e., towards deeper water) when they encountered water depths between 10 and 20 cm. Snails tended to move toward shallower water in water depths ???50 cm, suggesting that snails were avoiding deep water areas such as canals and sloughs. Of the 11 BC snails originally located in the area that eventually went dry, three (27%) were found in deep water refugia by the end of the study. Only one of the 31 LK snails escaped the drying event by moving to deeper water. Our results indicate that some snails may opportunistically escape drying events through movement. The tendency to move toward deeper water was statistically significant and indicates that this behavioral trait might enhance survival when the spatial extent of a dry down is limited. However, as water level falls below 10 cm, snails stop moving and become stranded. As the spatial extent of a dry down increases, we predict that the number of snails stranded would increase proportionally. Stranded Pomacea paludosa must contend with dry marsh conditions, possibly by aestivation. Little more than anecdotal information has been published on P. paludosa aestivation, but it is a common adaptation among other apple snails (Caenogastropoda: Ampullaridae). ?? 2002, The Society of Wetland Scientists.

Darby, P.C.; Bennetts, R.E.; Miller, S.J.; Percival, H.F.

2002-01-01

356

Mechanisms and consequences of shell fouling in the kelp snail, Norrisia norrisi (Sowerby) (Trochidae): Indirect effects of octopus drilling  

Microsoft Academic Search

The kelp snail, Nowisia norrisi (Sowerby), dwells on the large kelps Macrocystis pyrifera (L.) and Eisenia arborea Areschoug, and is rare on benthic substrata. Approximately 4% of the snail population is dislodged from plants each day. Per capita mortality of snails on the benthos is an order of magnitude greater than individuals on kelp. Even though snails displaced to the

RUSSELL J. SCHMITT; CRAIG W. OSENBERG; MARC G. BERCOVITCH

1983-01-01

357

Survival of the faucet snail Bithynia tentaculata after chemical disinfection, pH extremes, and heated water bath treatments  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bithynia tentaculata, the faucet snail, is a non indigenous aquatic snail from Eurasia that was introduced into Lake Michigan in 1871. The snail’s distribution in the United States has expanded to the mid-Atlantic states and the drainage basin of the Great Lakes and most recently to the Mississippi...

358

Freshwater Ecoregions of the World  

NSDL National Science Digital Library

Designed as a collaborative venture between the Nature Conservancy and the World Wildlife Fund, the Freshwater Ecoregions of the World (FEOW) site provides a dynamic visual representation of the Earth's freshwater biodiversity. Visitors to the site can find detailed information about 426 different freshwater systems from China to Chile. First-time users can click on the map of the world on the homepage, or they can also click on the "Highlights" area. Visitors with defined interests can also use the "Find an Ecoregion" section to perform a detailed search across the entire database of regions, and they can also browse by country, major habitat type, and major rivers. It's easy to see how this site would be a terrific resource for ecology students in high school or college.

359

Laboratory evaluation of Gambusia affinis fish as predators of the schistosome-bearing snails Bulinus truncatus.  

PubMed

In this laboratory-based study involving numerous experiments, it was demonstrated that the mosquito fish Gambusia affinis preys effectively upon the schistosome-bearing snail Bulinus truncatus, even in the presence of an alternative source of food. Egg masses and juvenile snails less than or equal to 2 mm in size are preferred. Individual eggs are nibbled, and the tiny snails with fragile shells are swallowed and digested. In the absence of other foods, the fish consume the flesh of snails 3 to 6 mm in size, leaving their empty shells intact. The larger snails are unharmed, but their offspring could be eradicated by the fish under favourable conditions. PMID:3755766

Acra, A; Milki, R; Raffoul, Z; Karahagopian, Y; Fletcher, M

1986-02-01

360

Silver bioaccumulation dynamics in a freshwater invertebrate after aqueous and dietary exposures to nanosized and ionic Ag  

USGS Publications Warehouse

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.

le Croteau, Marie-Noe; Misra, Superb K.; Luoma, Samuel N.; Valsami-Jones, Eugenia

2011-01-01

361

Effects of 17?-ethynylestradiol, fluoxetine, and the mixture on life history traits and population growth rates in a freshwater gastropod.  

PubMed

Pharmaceutical and personal care products (PPCPs), some of which have endocrine-disrupting effects at environmentally relevant concentrations, have been detected in many surface waters. The authors evaluated the effects of 2 common endocrine disrupting PPCPs on the life history traits of the snail, Physa pomilia, using a life table response experiment with snails raised in environmentally relevant concentrations of 17?-ethynylestradiol (EE2), fluoxetine, or their mixture. Exposure to fluoxetine or the mixture reduced snail reproduction, but EE2 did not. Generally, individual life history traits were affected minimally by the PPCPs, but when integrated using a demographic model, all 3 chemical exposure scenarios decreased population growth rates, with the EE2 and fluoxetine mixture causing the most adverse effects. Overall, the results provide additional insight into the effects of PPCPs on freshwater invertebrates and point to the importance of testing simultaneous exposures to multiple PPCPs. In addition, using a demographic model to integrate individual endpoints provided insights into effects that were not apparent from individual life history traits alone and suggest at least a potential for adverse ecological effects under realistic environmental exposures concentrations. PMID:23983099

Luna, Tamara O; Plautz, Stephanie C; Salice, Christopher J

2013-12-01

362

GLOBAL CHANGE AND TIDAL FRESHWATER WETLANDS  

E-print Network

Chapter 23 GLOBAL CHANGE AND TIDAL FRESHWATER WETLANDS: SCENARIOS AND IMPACTS Scott C. Neubauer Tidal Freshwater Wetlands, edited by Aat Barendregt, Dennis Whigham & Andrew Baldwin 2009, viii + 320pp Publishers GmbH This chapter was originally published in the book ,,Tidal Freshwater Wetlands". The copy

Neubauer, Scott C.

363

Extinction Rates of North American Freshwater Fauna  

Microsoft Academic Search

Since 1900, 123 freshwater animal species have been recorded as extinct in North America. Hun- dreds of additional species of fishes, mollusks, crayfishes, and amphibians are considered imperiled. Using an exponential decay model, we derived recent and future extinction rates for North American freshwater fauna that are five times higher than those for terrestrial fauna. Assuming that imperiled freshwater species

Anthony Ricciardi; Joseph B. Rasmussen

1999-01-01

364

Freshwater Ecology. LC Science Tracer Bullet.  

ERIC Educational Resources Information Center

Freshwater ecosystems include lakes, ponds, streams, rivers, and certain types of wetlands. This literature and resources guide is not intended to be a comprehensive bibliography on freshwater ecology; the guide is designed--as the name of the series implies--to put the reader or student "on target." Other literature guides related to freshwater

Niskern, Diana, Comp.

365

Inhabitants of the Fresh-Water Community.  

ERIC Educational Resources Information Center

This learner's guide is designed to assist middle school students in studying freshwater organisms. Following a brief introduction to freshwater ecology, simple line drawings facilitate the identification of plants and animals common to Florida's freshwater ecosystems. Emphasis of the short text which accompanies each illustration is upon the…

Jorgensen, Joseph; Schroeder, Marlene

366

Snail coordinately regulates downstream pathways to control multiple aspects of mammalian neural precursor development.  

PubMed

The Snail transcription factor plays a key role in regulating diverse developmental processes but is not thought to play a role in mammalian neural precursors. Here, we have examined radial glial precursor cells of the embryonic murine cortex and demonstrate that Snail regulates their survival, self-renewal, and differentiation into intermediate progenitors and neurons via two distinct and separable target pathways. First, Snail promotes cell survival by antagonizing a p53-dependent death pathway because coincident p53 knockdown rescues survival deficits caused by Snail knockdown. Second, we show that the cell cycle phosphatase Cdc25b is regulated by Snail in radial precursors and that Cdc25b coexpression is sufficient to rescue the decreased radial precursor proliferation and differentiation observed upon Snail knockdown. Thus, Snail acts via p53 and Cdc25b to coordinately regulate multiple aspects of mammalian embryonic neural precursor biology. PMID:24719096

Zander, Mark A; Burns, Sarah E; Yang, Guang; Kaplan, David R; Miller, Freda D

2014-04-01

367

Snail Coordinately Regulates Downstream Pathways to Control Multiple Aspects of Mammalian Neural Precursor Development  

PubMed Central

The Snail transcription factor plays a key role in regulating diverse developmental processes but is not thought to play a role in mammalian neural precursors. Here, we have examined radial glial precursor cells of the embryonic murine cortex and demonstrate that Snail regulates their survival, self-renewal, and differentiation into intermediate progenitors and neurons via two distinct and separable target pathways. First, Snail promotes cell survival by antagonizing a p53-dependent death pathway because coincident p53 knockdown rescues survival deficits caused by Snail knockdown. Second, we show that the cell cycle phosphatase Cdc25b is regulated by Snail in radial precursors and that Cdc25b coexpression is sufficient to rescue the decreased radial precursor proliferation and differentiation observed upon Snail knockdown. Thus, Snail acts via p53 and Cdc25b to coordinately regulate multiple aspects of mammalian embryonic neural precursor biology. PMID:24719096

Zander, Mark A.; Burns, Sarah E.; Yang, Guang; Kaplan, David R.

2014-01-01

368

Euparyphium albuferensis and Echinostoma friedi (Trematoda: Echinostomatidae): experimental cercarial transmission success in sympatric snail communities.  

PubMed

Euparyphium albuferensis and Echinostoma friedi cercarial infectivity to four species of sympatric snails was examined under single- or multiple-choice laboratory conditions to show the level of parasite-snail host compatibility. Radix peregra, Lymnaeafuscus, Physella acuta and Gyraulus chinensis act as second intermediate hosts of both parasite species although different cercarial transmission success (CTS) was observed. In single-host experiments, R. peregra and P. acuta showed a high degree of compatibility with E. albuferensis, while only P. acuta in the case of E. friedi. In two-choice snail communities, a snail with high CTS increased the values of another with low compatibility, in both parasite species. In multiple-choice snail communities, high CTS of some hosts decreased, while low CTS of other hosts increased. The degree of parasite-host compatibility of each snail species could be determined by the presence of other snails in the community. PMID:18666415

Muñoz-Antoli, Carla; Marin, Antoni; Vidal, Amparo; Toledo, Rafael; Esteban, José Guillermo

2008-06-01

369

Agonistic Behavior in Freshwater Crayfish  

E-print Network

Agonistic Behavior in Freshwater Crayfish The Influence of Intrinsic and Extrinsic Factors on Aggressive Encounters and Dominance 5 Paul A. Moore During aggressive fights, crayfish Orconectes rusticus question, a crustacean system, based on the crayfish, has been adopted as a model for social behavior

Moore, Paul A.

370

BIODIVERSITY Freshwater fish introductions in  

E-print Network

´a-Berthou5 , D. L. Morgan6 , I. Arismendi7 , J. A. Day1 , C. L. Griffiths1,2 and P. H. Skelton8 INTRODUCTION Freshwater ecosystems are subjected to the full range of anthropogenic threats, including habitat loss State University, Chico, CA 95929, USA, 4 School of Aquatic and Fishery Sciences, University

Olden, Julian D.

371

Flying shells: historical dispersal of marine snails across Central America  

PubMed Central

The geological rise of the Central American Isthmus separated the Pacific and the Atlantic oceans about 3 Ma, creating a formidable barrier to dispersal for marine species. However, similar to Simpson's proposal that terrestrial species can ‘win sweepstakes routes’—whereby highly improbable dispersal events result in colonization across geographical barriers—marine species may also breach land barriers given enough time. To test this hypothesis, we asked whether intertidal marine snails have crossed Central America to successfully establish in new ocean basins. We used a mitochondrial DNA genetic comparison of sister snails (Cerithideopsis spp.) separated by the rise of the Isthmus. Genetic variation in these snails revealed evidence of at least two successful dispersal events between the Pacific and the Atlantic after the final closure of the Isthmus. A combination of ancestral area analyses and molecular dating techniques indicated that dispersal from the Pacific to the Atlantic occurred about 750 000 years ago and that dispersal in the opposite direction occurred about 72 000 years ago. The geographical distribution of haplotypes and published field evidence further suggest that migratory shorebirds transported the snails across Central America at the Isthmus of Tehuantepec in southern Mexico. Migratory birds could disperse other intertidal invertebrates this way, suggesting the Central American Isthmus may not be as impassable for marine species as previously assumed. PMID:21920976

Miura, Osamu; Torchin, Mark E.; Bermingham, Eldredge; Jacobs, David K.; Hechinger, Ryan F.

2012-01-01

372

[Evaluation of molluscicidal effect of nicotinanilide against Oncomelania snails].  

PubMed

Both nicotinanilide hydrochloride and nicotinanilide sulfate are water-soluble, their IC50 and LC90 against Oncomelania snails being around 0.3 mg/L and 0.5 mg/L, respectively, during 24 hour exposure at 25 degrees C followed by a 7-day recovery period. The laboratory tests and field trials showed that over 90% of snails were killed within 3 days exposure at 1-2 mg/L, and that 18.4%-100% snails on moist soil were killed at over 20 degrees C, exposed to spraying dosage of 1-2 g/m2 for 1-3 days. The chemical is highly effective against snails eggs at early stage (cell stage). The LC50 of nicotinanilide to Aristichthys nobilis and Pseudorasbora parva is about 200 mg/L. The acute oral LD50 in mice is about 2 g/kg. Plants tolerate the chemical at 1-2 g/m2, but some leaves wilted at greater than or equal to 5 g/m2, dicotyledon in particular. Dermatitis has been reported in individuals frequently exposing to nicotinanilide wettable powder during massive spraying. PMID:1959178

Chen, Z P; Tao, H Q; Hua, D S; Shen, B R; Chan, H L

1991-01-01

373

The snail superfamily of zinc-finger transcription factors  

Microsoft Academic Search

The Snail superfamily of zinc-finger transcription factors is involved in processes that imply pronounced cell movements, both during embryonic development and in the acquisition of invasive and migratory properties during tumour progression. Different family members have also been implicated in the signalling cascade that confers left–right identity, as well as in the formation of appendages, neural differentiation, cell division and

M. Angela Nieto

2002-01-01

374

A new glycosaminoglycan from the giant African snail Achatina fulica.  

PubMed

A new glycosaminoglycan has been isolated from the giant African snail Achatina fulica. This polysaccharide had a molecular weight of 29,000, calculated based on the viscometry, and a uniform repeating disaccharide structure of -->4)-2-acetyl,2-deoxy-alpha-D-glucopyranose (1-->4)-2-sulfo-alpha-L-idopyranosyluronic acid (1-->. This polysaccharide represents a new, previously undescribed glycosaminoglycan. It is related to the heparin and heparan sulfate families of glycosaminoglycans but is distinctly different from all known members of these classes of glycosaminoglycans. The structure of this polysaccharide, with adjacent N-acetylglucosamine and 2-sulfo-iduronic acid residues, also poses interesting questions about how it is made in light of our current understanding of the biosynthesis of heparin and heparan sulfate. This glycosaminoglycan represents 3-5% of the dry weight of this snail's soft body tissues, suggesting important biological roles for the survival of this organism, and may offer new means to control this pest. Snail glycosaminoglycan tightly binds divalent cations, such as copper(II), suggesting a primary role in metal uptake in the snail. Finally, this new polysaccharide might be applied, like the Escherichia coli K5 capsular polysaccharide, to the study of glycosaminoglycan biosynthesis and to the semisynthesis of new glycosaminoglycan analogs having important biological activities. PMID:8662607

Kim, Y S; Jo, Y Y; Chang, I M; Toida, T; Park, Y; Linhardt, R J

1996-05-17

375

Allying with armored snails: the complete genome of gammaproteobacterial endosymbiont.  

E-print Network

25 8 8 Allying with armored snails: the complete genome 23687004 20109005 TEL: 0138-40-5570 FAX :0138-40-5570 E-mail: nakagawa@fish.hokudai.ac.jp http://micro.fish.hokudai.ac.jp/labs/Site/Scaly-Foot.html #12; 1. 4.5cm 1. #12; 2. #12; 1 2001 4 Van

Tachizawa, Kazuya

376

Food Choice in the Common Snail (Helix Aspersa).  

ERIC Educational Resources Information Center

The easily obtained common snail shows interesting dietary preferences which can be the source of several simple experiments. Specific student instructions are given for quantitative and comparative studies using cabbage, lettuce, carrot, rutabaga, and onion. Suggestions for laboratory setup and further work are included. (DH)

Gill, John; Howell, Pauline

1985-01-01

377

Mitochondrial Phylogeny of Extant Hawaiian Tree Snails (Achatinellinae)  

Microsoft Academic Search

Hawaiian tree snails in the endemic subfamily Achatinellinae display a staggering variety of shell colors and banding patterns. Despite numerous attempts to classify this morphological variation, a conclusive phylogeny has not been proposed. To improve conservation efforts, we sought to better understand the species identities and phylogenetic relationships among the extant species of Achatinella and Partulina using partial mitochondrial 16S

Robert W Thacker; Michael G Hadfield

2000-01-01

378

MOLLUSCICIDAL ACTIVITY OF VULGARONE B AGAINST RAM'S HORN SNAIL  

Technology Transfer Automated Retrieval System (TEKTRAN)

The ram's horn snail (Planorbdella trivolvis) is an intermediate host for a digenetic trematode (Bolbophorus confusus) that has recently been discovered to be a significant problem in commercial catfish (Ictalurus punctatus) production ponds in the Mississippi Delta region of the USA. In these catf...

379

Land Snail Ecology and Biogeography of Eastern Maine  

E-print Network

in the state (Nesovitrea binneyana, Planogyra asteriscus, Striatura ferrea, Striatura milium, VertigoLand Snail Ecology and Biogeography of Eastern Maine Vertigo bollesiana Vertigo nylanderi Vertigo bollesiana, and Vertigo ventricosa). In the early 20th Century, Olaf Nylander of Caribou also made extensive

Nekola, Jeffrey C.

380

Sequestration of lichen compounds by three species of terrestrial snails.  

PubMed

Three species of lichen-grazing snails,Balea perversa, Chondria clienta, andHelicigona lapicida, all from the Swedish island of Öland, were found to sequester lichen compounds when feeding on the crustous lichen speciesAspicila calcarea, Caloplaca flavovirescens, Lecanora muralis, Physcia adscendens, Tephromela atra, andXanthoria parietina. The lichen compounds detected in the soft bodies of the snail species analyzed included the anthraquinone parietin, the depside atranorin, as well as a presumable degradation product of the latter. Other lichen compounds such as (+)-usnic acid or ?-collatolic acid were not found in the soft bodies but were only detected in the feces, suggesting selective uptake of lichen compounds by the snails. In individuals ofC. clienta initially fed on the lichenX. parietina, the amount of sequestered parietin decreased over time on a parietin-free diet but was still detectable in the soft bodies after 28 days. In the ovoviviparous land snail,B. perversa, sequestered parietin was transferred from the mother to the eggs in the reproductive tract. PMID:24234022

Hesbacher, S; Baur, B; Baur, A; Proksch, P

1995-02-01

381

DNA barcodes reveal the presence of the introduced freshwater leech Helobdella europaea in Spain.  

PubMed

Abstract We report the finding of the freshwater leech Helobdella europaea in Spain for the first time. Three leech specimens were found attached to the European pond turtle Emys orbicularis. Helobdella europaea is not a blood feeder and, like all members of the genus, feeds on the hemolymph of aquatic invertebrates including snails and worms. Despite the fact that the original geographical distribution or source population of this species is unknown, the close relationship between H. europaea and leeches of the "triserialis" series (sensu Sawyer, 1986) suggests a New World origin. Given its ability to invade and persist in new environments, this leech has been described as a new species by local taxonomists resulting in some nomenclatural problems. The presence of this introduced organism in Spain may represent serious obstacles to the current efforts to preserve endemic fauna and the potential negative impacts of this species in European environments should be investigated. PMID:23885897

Reyes-Prieto, Mariana; Oceguera-Figueroa, Alejandro; Snell, Sara; Negredo, Alicia; Barba, Emilio; Fernández, Luis; Moya, Andrés; Latorre, Amparo

2014-10-01

382

Molecular phylogeny and evolution of the cone snails (Gastropoda, Conoidea).  

PubMed

We present a large-scale molecular phylogeny that includes 320 of the 761 recognized valid species of the cone snails (Conus), one of the most diverse groups of marine molluscs, based on three mitochondrial genes (COI, 16S rDNA and 12S rDNA). This is the first phylogeny of the taxon to employ concatenated sequences of several genes, and it includes more than twice as many species as the last published molecular phylogeny of the entire group nearly a decade ago. Most of the numerous molecular phylogenies published during the last 15years are limited to rather small fractions of its species diversity. Bayesian and maximum likelihood analyses are mostly congruent and confirm the presence of three previously reported highly divergent lineages among cone snails, and one identified here using molecular data. About 85% of the species cluster in the single Large Major Clade; the others are divided between the Small Major Clade (?12%), the Conus californicus lineage (one species), and a newly defined clade (?3%). We also define several subclades within the Large and Small major clades, but most of their relationships remain poorly supported. To illustrate the usefulness of molecular phylogenies in addressing specific evolutionary questions, we analyse the evolution of the diet, the biogeography and the toxins of cone snails. All cone snails whose feeding biology is known inject venom into large prey animals and swallow them whole. Predation on polychaete worms is inferred as the ancestral state, and diet shifts to molluscs and fishes occurred rarely. The ancestor of cone snails probably originated from the Indo-Pacific; rather few colonisations of other biogeographic provinces have probably occurred. A new classification of the Conidae, based on the molecular phylogeny, is published in an accompanying paper. PMID:24878223

Puillandre, N; Bouchet, P; Duda, T F; Kauferstein, S; Kohn, A J; Olivera, B M; Watkins, M; Meyer, C

2014-09-01

383

Acute toxicity of nitrate and nitrite to sensitive freshwater insects, mollusks, and a crustacean.  

PubMed

Both point- and nonpoint-sources of pollution have contributed to increased inorganic nitrogen concentrations in freshwater ecosystems. Although numerous studies have investigated the toxic effects of ammonia on freshwater species, relatively little work has been performed to characterize the acute toxicity of the other two common inorganic nitrogen species: nitrate and nitrite. In particular, to our knowledge, no published data exist on the toxicity of nitrate and nitrite to North American freshwater bivalves (Mollusca) or stoneflies (Insecta, Plecoptera). We conducted acute (96-h) nitrate and nitrite toxicity tests with two stonefly species (Allocapnia vivipara and Amphinemura delosa), an amphipod (Hyalella azteca), two freshwater unionid mussels (Lampsilis siliquoidea and Megalonaias nervosa), a fingernail clam (Sphaerium simile), and a pond snail (Lymnaea stagnalis). Overall, we did not observe a particularly wide degree of variation in sensitivity to nitrate, with median lethal concentrations ranging from 357 to 937 mg NO(3)-N/l; furthermore, no particular taxonomic group appeared to be more sensitive to nitrate than any other. In our nitrite tests, the two stoneflies tested were by far the most sensitive, and the three mollusks tested were the least sensitive. In contrast to what was observed in the nitrate tests, variation among species in sensitivity to nitrite spanned two orders of magnitude. Examination of the updated nitrite database, including previously published data, clearly showed that insects tended to be more sensitive than crustaceans, which were in turn more sensitive than mollusks. Although the toxic mechanism of nitrite is generally thought to be the conversion of oxygen-carrying pigments into forms that cannot carry oxygen, our observed trend in sensitivity of broad taxonomic groups, along with information on respiratory pigments in those groups, suggests that some other yet unknown mechanism may be even more important. PMID:21877224

Soucek, D J; Dickinson, A

2012-02-01

384

Targeted Inactivation of Snail Family EMT Regulatory Factors by a Co(III)-Ebox Conjugate  

PubMed Central

Snail family proteins are core EMT (epithelial-mesenchymal transition) regulatory factors that play essential roles in both development and disease processes and have been associated with metastasis in carcinomas. Snail factors are required for the formation of neural crest stem cells in most vertebrate embryos, as well as for the migratory invasive behavior of these cells. Snail factors have recently been linked to the formation of cancer stem cells, and expression of Snail proteins may be associated with tumor recurrence and resistance to chemotherapy and radiotherapy. We report that Co(III)-Ebox is a potent inhibitor of Snail- mediated transcriptional repression in breast cancer cells and in the neural crest of Xenopus. We further show that the activity of Co(III)-Ebox can be modulated by temperature, increasing the utility of this conjugate as a Snail inhibitor in model organisms. We exploit this feature to further delineate the requirements for Snail function during neural crest development, showing that in addition to the roles that Snail factors play in neural crest precursor formation and neural crest EMT/migration, inhibition of Snail function after the onset of neural crest migration leads to a loss of neural crest derived melanocytes. Co(III)-Ebox-mediated inhibition therefore provides a powerful tool for analysing the function of these core EMT factors with unparalleled temporal resolution. Moreover, the potency of Co(III)-Ebox as a Snail inhibitor in breast cancer cells suggests its potential as a therapeutic inhibitor of tumor progression and metastasis. PMID:22393397

Harney, Allison S.; Meade, Thomas J.; LaBonne, Carole

2012-01-01

385

Pseudosuccinea columella: age resistance to Calicophoron daubneyi infection in two snail populations  

PubMed Central

Individual infections of Egyptian and French Pseudosuccinea columella with five miracidia of Calicophoron daubneyi were carried out to determine whether this lymnaeid was capable of sustaining larval development of this parasite. On day 42 post-exposure (at 23 °C), infected snails were only noted in groups of individuals measuring 1 or 2 mm in height at miracidial exposure. Snail survival in the 2-mm groups was significantly higher than that noted in the 1-mm snails, whatever the geographic origin of snail population. In contrast, prevalence of C. daubneyi infection was significantly greater in the 1-mm groups (15–20% versus 3.4–4.0% in the 2-mm snails). Low values were noted for the mean shell growth of infected snails at their death (3.1–4.0 mm) and the mean number of cercariae (<9 in the 1-mm groups, <19 in the 2-mm snails). No significant differences between snail populations and snails groups were noted for these last two parameters. Most infected snails died after a single cercarial shedding wave. Both populations of P. columella showed an age resistance to C. daubneyi infection and only juveniles measuring 2 mm or less in shell height at exposure can ensure larval development of this digenean up to cercarial shedding. PMID:25664810

Dar, Yasser; Rondelaud, Daniel; Vignoles, Philippe; Dreyfuss, Gilles

2015-01-01

386

Snail Recruits Ring1B to Mediate Transcriptional Repression and Cell Migration in Pancreatic Cancer Cells  

PubMed Central

Transcriptional repressor Snail is a master regulator of epithelial–mesenchymal transition (EMT), yet the epigenetic mechanism governing Snail to induce EMT is not well understood. Here, we report that in pancreatic ductal adenocarcinoma (PDAC), elevated levels of the ubiquitin E3 ligase Ring1B and Snail, along with elevated monoubiquitination of H2A at K119 (H2AK119Ub1), are highly correlated with poor survival. Mechanistic investigations identified Ring1B as a Snail-interacting protein and showed that the carboxyl zinc fingers of Snail recruit Ring1B and its paralog Ring1A to repress its target promoters. Simultaneous depletion of Ring1A and Ring1B in pancreatic cancer cells decreased Snail binding to the target chromatin, abolished H2AK119Ub1 modification, and thereby compromised Snail-mediated transcriptional repression and cell migration. We found that Ring1B and the SNAG-associated chromatin modifier EZH2 formed distinct protein complexes with Snail and that EZH2 was required for Snail-Ring1A/B recruitment to the target promoter. Collectively, our results unravel an epigenetic mechanism underlying transcriptional repression by Snail, suggest Ring1A/B as a candidate therapeutic target, and identify H2AK119Ub1 as a potential biomarker for PDAC diagnosis and prognosis. Cancer Res; 74(16); 4353-63. ©2014 AACR PMID:24903147

Chen, Jiangzhi; Xu, Hong; Zou, Xiuqun; Wang, Jiamin; Zhu, Yi; Chen, Hao; Shen, Baiyong; Deng, Xiaxing; Zhou, Aiwu; Chin, Y. Eugene; Rauscher, Frank J.; Peng, Chenghong; Hou, Zhaoyuan

2014-01-01

387

Overexpression of Snail in retinal pigment epithelial triggered epithelial-mesenchymal transition.  

PubMed

Snail transcription factor has been implicated as an important regulator in epithelial-mesenchymal transition (EMT) during tumourigenesis and fibrogenesis. Our previous work showed that Snail transcription factor was activated in transforming growth factor ?1 (TGF-?1) induced EMT in retinal pigment epithelial (RPE) cells and may contribute to the development of retinal fibrotic disease such as proliferative vitreoretinopathy (PVR). However, whether Snail alone has a direct role on retinal pigment epithelial-mesenchymal transition has not been investigated. Here, we analyzed the capacity of Snail to drive EMT in human RPE cells. A vector encoding Snail gene or an empty vector were transfected into human RPE cell lines ARPE-19 respectively. Snail overexpression in ARPE-19 cells resulted in EMT, which was characterized by the expected phenotypic transition from a typical epithelial morphology to mesenchymal spindle-shaped. The expression of epithelial markers E-cadherin and Zona occludin-1 (ZO-1) were down-regulated, whereas mesenchymal markers a-smooth muscle actin (a-SMA) and fibronectin were up-regulated in Snail expression vector transfected cells. In addition, ectopic expression of Snail significantly enhanced ARPE-19 cell motility and migration. The present data suggest that overexpression of Snail in ARPE-19 cells could directly trigger EMT. These results may provide novel insight into understanding the regulator role of Snail in the development of retinal pigment epithelial-mesenchymal transition. PMID:24607896

Li, Hui; Li, Min; Xu, Ding; Zhao, Chun; Liu, Guodong; Wang, Fang

2014-03-28

388

Pseudosuccinea columella: age resistance to Calicophoron daubneyi infection in two snail populations.  

PubMed

Individual infections of Egyptian and French Pseudosuccinea columella with five miracidia of Calicophoron daubneyi were carried out to determine whether this lymnaeid was capable of sustaining larval development of this parasite. On day 42 post-exposure (at 23 °C), infected snails were only noted in groups of individuals measuring 1 or 2 mm in height at miracidial exposure. Snail survival in the 2-mm groups was significantly higher than that noted in the 1-mm snails, whatever the geographic origin of snail population. In contrast, prevalence of C. daubneyi infection was significantly greater in the 1-mm groups (15-20% versus 3.4-4.0% in the 2-mm snails). Low values were noted for the mean shell growth of infected snails at their death (3.1-4.0 mm) and the mean number of cercariae (<9 in the 1-mm groups, <19 in the 2-mm snails). No significant differences between snail populations and snails groups were noted for these last two parameters. Most infected snails died after a single cercarial shedding wave. Both populations of P. columella showed an age resistance to C. daubneyi infection and only juveniles measuring 2 mm or less in shell height at exposure can ensure larval development of this digenean up to cercarial shedding. PMID:25664810

Dar, Yasser; Rondelaud, Daniel; Vignoles, Philippe; Dreyfuss, Gilles

2015-01-01

389

Trematode communities in snails can indicate impact and recovery from hurricanes in a tropical coastal lagoon.  

PubMed

In September 2002, Hurricane Isidore devastated the Yucatán Peninsula, Mexico. To understand its effects on the parasites of aquatic organisms, we analyzed long-term monthly population data of the horn snail Cerithidea pliculosa and its trematode communities in Celestún, Yucatán, Mexico before and after the hurricane (February 2001 to December 2009). Five trematode species occurred in the snail population: Mesostephanus appendiculatoides, Euhaplorchis californiensis, two species of the genus Renicola and one Heterophyidae gen. sp. Because these parasites use snails as first intermediate hosts, fishes as second intermediate hosts and birds as final hosts, their presence in snails depends on food webs. No snails were present at the sampled sites for 6 months after the hurricane. After snails recolonised the site, no trematodes were found in snails until 14 months after the hurricane. It took several years for snail and trematode populations to recover. Our results suggest that the increase in the occurrence of hurricanes predicted due to climate change can impact upon parasites with complex life cycles. However, both the snail populations and their parasite communities eventually reached numbers of individuals and species similar to those before the hurricane. Thus, the trematode parasites of snails can be useful indicators of coastal lagoon ecosystem degradation and recovery. PMID:22079832

Aguirre-Macedo, María Leopoldina; Vidal-Martínez, Victor M; Lafferty, Kevin D

2011-11-01

390

Reversing the Resistance Phenotype of the Biomphalaria glabrata Snail Host Schistosoma mansoni Infection by Temperature Modulation  

PubMed Central

Biomphalaria glabrata snails that display either resistant or susceptible phenotypes to the parasitic trematode, Schistosoma mansoni provide an invaluable resource towards elucidating the molecular basis of the snail-host/schistosome relationship. Previously, we showed that induction of stress genes either after heat-shock or parasite infection was a major feature distinguishing juvenile susceptible snails from their resistant counterparts. In order to examine this apparent association between heat stress and snail susceptibility, we investigated the effect of temperature modulation in the resistant snail stock, BS-90. Here, we show that, incubated for up to 4 hrs at 32°C prior to infection, these resistant snails became susceptible to infection, i.e. shedding cercariae at 5 weeks post exposure (PE) while unstressed resistant snails, as expected, remained resistant. This suggests that susceptibility to infection by this resistant snail phenotype is temperature-sensitive (ts). Additionally, resistant snails treated with the Hsp 90 specific inhibitor, geldanamycin (GA) after heat stress, were no longer susceptible to infection, retaining their resistant phenotype. Consistently, susceptible snail phenotypes treated with 100 mM GA before parasite exposure also remained uninfected. These results provide direct evidence for the induction of stress genes (heat shock proteins; Hsp 70, Hsp 90 and the reverse transcriptase [RT] domain of the nimbus non-LTR retrotransposon) in B. glabrata susceptibility to S. mansoni infection and characterize the resistant BS-90 snails as a temperature-sensitive phenotype. This study of reversing snail susceptibility phenotypes to S. mansoni provides an opportunity to directly track molecular pathway(s) that underlie the B. glabrata snail's ability to either sustain or destroy the S. mansoni parasite. PMID:22577362

Ittiprasert, Wannaporn; Knight, Matty

2012-01-01

391

Freshwater and Marine Image Bank  

NSDL National Science Digital Library

The University of Washington Libraries has digitized 21,000 images of freshwater and marine life taken from 1735-1924 that populated various publications about the topic. Some of the publications include 18th and 19th century books with hand-colored images, stereographs, and publications of the U.S. Bureau of Fisheries and related agencies that contain a slew of illustrations. On the far right hand side of the homepage is a list of 24 sample subject areas that the images fall into, including "aquaculture", "mollusks", "polar subjects", and "water birds". Visitors wishing to see the complete list of subjects should click on "Browse Subjects", in the top right of the homepage. The "Other Sources" link at the bottom right hand side of the page has links to over a dozen other websites that contain digitized freshwater and marine images, such as "Sea Lamprey Images", "Shoreline Aerial Photos", and "Reef Snapshots", just to name a few.

392

Metabolic acceleration in the pond snail Lymnaea stagnalis?  

NASA Astrophysics Data System (ADS)

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 is not the only explanation for metabolic acceleration in animals, we discuss the possible other explanations for this pattern in L. stagnalis.

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

2014-11-01

393

A speciation gene for left–right reversal in snails results in anti-predator adaptation  

PubMed Central

How speciation genes can spread in a population is poorly understood. In land snails, a single gene for left–right reversal could be responsible for instant speciation, because dextral and sinistral snails have difficulty in mating. However, the traditional two-locus speciation model predicts that a mating disadvantage for the reversal should counteract this speciation. In this study, we show that specialized snake predation of the dextral majority drives prey speciation by reversal. Our experiments demonstrate that sinistral Satsuma snails (Stylommatophora: Camaenidae) survive predation by Pareas iwasakii (Colubroidea: Pareatidae). Worldwide biogeography reveals that stylommatophoran snail speciation by reversal has been accelerated in the range of pareatid snakes, especially in snails that gain stronger anti-snake defense and reproductive isolation from dextrals by sinistrality. Molecular phylogeny of Satsuma snails further provides intriguing evidence of repetitive speciation under snake predation. Our study demonstrates that a speciation gene can be fixed in populations by positive pleiotropic effects on survival. PMID:21139578

Hoso, Masaki; Kameda, Yuichi; Wu, Shu-Ping; Asami, Takahiro; Kato, Makoto; Hori, Michio

2010-01-01

394

Thermal susceptibility of Salmonella in the Moroccan food snail, Helix aspersa.  

PubMed

Thirty samples of 10-15 Helix aspersa food snails were examined for Salmonella by a surface rinsing method and by analysis of whole snails rinsed with 70% ethanol. Thirteen samples were positive by the rinsing method and 6 were positive by whole snail analysis, with this difference being significant (P less than 0.01). Although Salmonella contamination in H. aspersa appeared to be predominantly surface, the pathogen was also found within the snail meat. The ability of surface and subsurface Salmonella organisms to survive in cooked snails was determined in 90 samples. Thermocouple readings indicated that an internal temperature of at least 200 degrees F (93 degrees C) was reached within the snail meat during cooking by a typical recipe. This temperature was sufficient to kill both surface and subsurface Salmonella in 29 samples positive for the pathogen prior to heating. A variety of serotypes representing several somatic groups was isolated. PMID:1194178

Andrews, W H; Wilson, C R

1975-11-01

395

Measurement of Selected Enzymatic Activities in Solanum nigrum-Treated Biomphalaria arabica Snails  

NASA Astrophysics Data System (ADS)

In the present study, glucose, acid and alkaline phosphatases (ACP and ALP), ?-amylase and lipase were measured for the first time in tissue homogenates of Biomphalaria arabica snails, molluscan intermediate host for Schistosoma mansoni in Saudi Arabia. Also, the effect of sublethal concentrations (LC25) of dry powdered Solanum nigrum leaf was tested as plant molluscicide against this snail species. The tested enzymes were altered in molluscicide-treated snails compared to control. While ALP and amylase were slightly affected, ACP and lipase were significantly altered. Glucose as an important energy source for a successful schistosome-snail relationship was significantly reduced in molluscicide-treated snails. In conclusion, sublethal concentration of the molluscicide showed potent effect in disturbing snail biochemistry which may render them physiologically unsuitable for the developing of schistosome parasite. This could be considered as a promising strategy to control the disease.

Al-Daihan, Sooad

396

Central and peripheral expression of genes coding for egg-laying inducing and insulin-related peptides in a snail.  

PubMed

Egg laying in the hermaphrodite freshwater snail Lymnaea stagnalis is a highly complex activity, including a series of internal activities (ovulation, egg and egg mass formation) which are closely correlated to a pattern of behaviours (alteration of locomotion and feeding, specific postures, oviposition). In this snail egg laying is induced by the neuroendocrine caudodorsal cells (CDCs), consisting of two homogeneous clusters at a total of 100 neurons. At egg laying these neurons release their products during a 60 min period of firing. The genes coding for these products have been cloned and characterized. There are two genes, CDCH-I and -II. Each gene codes for 12 peptides; one of these is the ovulation hormone (CDCH). The genes display over 90% homology. The most striking difference is a 17 bp deletion near the carboxy-terminal region. With immunocytochemistry and in situ hybridization both CDCH genes appeared to be expressed in the CDC and in paired groups of ectopic CDC-like neurons in the pleural ganglia, while a group of small neurons in the cerebral ganglia expresses the CDCH-I gene only. In addition, a widespread expression of the CDCH genes has been demonstrated in peripheral tissues. In the female part of the reproductive tract neurons were found to express the CDCH-I gene. In the male part of the tract exocrine secretory cells express the CDCH-I or -II gene. The gene products are secreted into the male tract and transferred to the female partner during copulation. Finally, sensory neurons in the head skin and mantle edge were found to express the CDCH-I gene. The presence of insulin-related peptides has been demonstrated in the brain as well as the digestive system of Lymnaea. The brain insulin-related peptides are produced in 4 groups of 50 giant neurons each (Light green cells, LGC). These neurons are involved in various physiological activities, related to body growth and glycogen metabolism. The major gene products expressed in the LGC have been cloned and characterized. It appeared that the predicted proteins represent three types of insulin-related molecules (MIP, molluscan insulin-related peptide). In these MIPs, those elements important in the determination of the tertiary structure, have been conserved. The MIP of the digestive system has been characterized up to now only at the peptide level. The snail gut MIP is more hydrophobic compared to bovine insulin. Cells containing MIP have been identified immunocytochemically in the gut epithelium. PMID:2510786

van Minnen, J; Smit, A B; Joosse, J

1989-01-01

397

A Population Growth Trend Analysis for Neotricula aperta, the Snail Intermediate Host of Schistosoma mekongi, after Construction of the Pak-Mun Dam  

PubMed Central

Background The Pak-Mun dam is a controversial hydro-power project on the Mun River in Northeast Thailand. The dam is sited in a habitat of the freshwater snail Neotricula aperta, which is the intermediate host for the parasitic blood-fluke Schistosoma mekongi causing Mekong schistosomiasis in humans in Cambodia and Laos. Few data are available which can be used to assess the effects of water resource development on N. aperta. The aim of this study was to obtain data and to analyze the possible impact of the dam on N. aperta population growth. Methodology/Principal Findings Estimated population densities were recorded for an N. aperta population in the Mun River 27 km upstream of Pak-Mun, from 1990 to 2011. The Pak-Mul dam began to operate in 1994. Population growth was modeled using a linear mixed model expression of a modified Gompertz stochastic state-space exponential growth model. The N. aperta population was found to be quite stable, with the estimated growth parameter not significantly different from zero. Nevertheless, some marked changes in snail population density were observed which were coincident with changes in dam operation policy. Conclusions/Significance The study found that there has been no marked increase in N. aperta population growth following operation of the Pak-Mun dam. The analysis did indicate a large and statistically significant increase in population density immediately after the dam came into operation; however, this increase was not persistent. The study has provided the first vital baseline data on N. aperta population behavior near to the Pak-Mun dam and suggests that the operation policy of the dam may have an impact on snail population density. Nevertheless, additional studies are required for other N. aperta populations in the Mun River and for an extended time series, to confirm or refine the findings of this work. PMID:24244775

Attwood, Stephen W.; Upatham, E. Suchart

2013-01-01

398

Determination of wing cell fate by the escargot and snail genes in Drosophila.  

PubMed

Inset appendages such as the wing and the leg are formed in response to inductive signals in the embryonic field. In Drosophila, cells receiving such signals initiate developmental programs which allow them to become imaginal discs. Subsequently, these discs autonomously organize patterns specific for each appendage. We here report that two related transcription factors, Escargot and Snail that are expressed in the embryonic wing disc, function as intrinsic determinants of the wing cell fate. In escargot or snail mutant embryos, wing-specific expression of Snail, Vestigial and beta-galactosidase regulated by escargot enhancer were found as well as in wild-type embryos. However, in escargot snail double mutant embryos, wing development proceeded until stage 13, but the marker expression was not maintained in later stages, and the invagination of the primordium was absent. From such analyses, it was concluded that Escargot and Snail expression in the wing disc are maintained by their auto- and crossactivation. Ubiquitous escargot or snail expression induced from the hsp70 promoter rescued the escargot snail double mutant phenotype with the effects confined to the prospective wing cells. Similar DNA binding specificities of Escargot and Snail suggest that they control the same set of genes required for wing development. We thus propose the following scenario for early wing disc development. Prospective wing cells respond to the induction by turning on escargot and snail transcription, and become competent for regulation by Escargot and Snail. Such cells initiate auto- and crossregulatory circuits of escargot and snail. The sustained Escargot and Snail expression then activates vestigial and other target genes that are essential for wing development. This maintains the commitment to the wing cell fate and induces wing-specific cell shape change. PMID:8620833

Fuse, N; Hirose, S; Hayashi, S

1996-04-01

399

Use of Bayluscide (Bayer 73) for Snail Control in Fish Ponds  

Microsoft Academic Search

Bayluscide applied to ponds on two commercial fish farms at five rates (from L1 to 13.5 kilogram per surface hectare) effectively controlled aquatic snails. Laboratory toxicity tests confirmed susceptibility of three endemic species of aquatic snail—Melanoides tuberculatus, Physella hendersoni, and Planorbella duryi—to Bayluscide. Observed 24-h concentrations lethal to 50% of snails (LC50) ranged from 0.062 to 0.085 mg\\/L, and 24-h

Ruth Francis-Floyd; James Gildea; Peggy Reed; Ruthellen Klinger

1997-01-01

400

Removal of corallivorous snails as a proactive tool for the conservation of acroporid corals.  

PubMed

Corallivorous snail feeding is a common source of tissue loss for the threatened coral, Acropora palmata, accounting for roughly one-quarter of tissue loss in monitored study plots over seven years. In contrast with larger threats such as bleaching, disease, or storms, corallivory by Coralliophila abbreviata is one of the few direct sources of partial mortality that may be locally managed. We conducted a field experiment to explore the effectiveness and feasibility of snail removal. Long-term monitoring plots on six reefs in the upper Florida Keys were assigned to one of three removal treatments: (1) removal from A. palmata only, (2) removal from all host coral species, or (3) no-removal controls. During the initial removal in June 2011, 436 snails were removed from twelve 150 m(2) plots. Snails were removed three additional times during a seven month "removal phase", then counted at five surveys over the next 19 months to track recolonization. At the conclusion, snails were collected, measured and sexed. Before-After-Control-Impact analysis revealed that both snail abundance and feeding scar prevalence were reduced in removal treatments compared to the control, but there was no difference between removal treatments. Recolonization by snails to baseline abundance is estimated to be 3.7 years and did not differ between removal treatments. Recolonization rate was significantly correlated with baseline snail abundance. Maximum snail size decreased from 47.0 mm to 34.6 mm in the removal treatments. The effort required to remove snails from A. palmata was 30 diver minutes per 150 m(2) plot, compared with 51 min to remove snails from all host corals. Since there was no additional benefit observed with removing snails from all host species, removals can be more efficiently focused on only A. palmata colonies and in areas where C. abbreviata abundance is high, to effectively conserve A. palmata in targeted areas. PMID:25469321

Williams, Dana E; Miller, Margaret W; Bright, Allan J; Cameron, Caitlin M

2014-01-01

401

Creosote compounds in snails obtained from Pensacola Bay, Florida, near an onshore hazardous-waste site  

USGS Publications Warehouse

Snails, Thais haemostoma, were collected from two areas offshore in Pensacola Bay, Florida, near an onshore hazardous-waste site. Tissue from the snails was extracted to isolate the lipophilic compounds and analyzed by gas chromatography/mass spectrometry. Along with naturally occurring compounds, the snail tissue contained large concentrations of polycyclic aromatic compounds, such as phenanthrene, acridine, dibenzothiophene, dibenzofuran, and benzo[a]pyrene. Many of these compounds were characteristic of creosote contamination associated with the onshore hazardous-waste site.

Rostad, C.E.; Pereira, W.E.

1987-01-01

402

Snail1 Protein in the Stroma as a New Putative Prognosis Marker for Colon Tumours  

Microsoft Academic Search

Over-expression of Snail1 gene transcriptional repressor promotes an epithelial-to-mesenchymal transition in epithelial tumour cell lines. Expression of Snail1 RNA has been associated to the pathogenesis of a number of malignancies; however, the lack of good monoclonal antibodies against this protein has precluded a definitive analysis of Snail1 protein. In this study, we aimed to determine the expression of this transcriptional

Clara Francí; Manel Gallén; Francesc Alameda; Teresa Baró; Mar Iglesias; Ismo Virtanen; Antonio García de Herreros; Patrick Callaerts

2009-01-01

403

The LIM Protein AJUBA Recruits Protein Arginine Methyltransferase 5 To Mediate SNAIL-Dependent Transcriptional Repression  

Microsoft Academic Search

The SNAIL transcription factor contains C-terminal tandem zinc finger motifs and an N-terminal SNAG repression domain. The members of the SNAIL family have recently emerged as major contributors to the processes of development and metastasis via the regulation of epithelial-mesenchymal transition events during embryonic development and tumor progression. However, the mechanisms by which SNAIL represses gene expression are largely undefined.

Zhaoyuan Hou; Hongzhuang Peng; Kasirajan Ayyanathan; Kai-Ping Yan; Ellen M. Langer; Gregory D. Longmore; Frank J. Rauscher

2008-01-01

404

Snail and Sonic Hedgehog activation in neuroendocrine tumors of the ileum  

Microsoft Academic Search

The transcription factor Snail represses E-cadherin and induces epithelial-mesenchymal transition, a process also exploited by invasive cancer cells. Aberrant Hedgehog (Hh) signaling was recently observed in a variety of epithelial cancers and it has been shown that the Hh target geneGli1 induces expression of Snail. In this study, we examined whether Snail and Sonic Hedgehog (SHH) are expressed in neuroendocrine

Volker Fendrich; Jens Waldmann; Farzad Esni; Annette Ramaswamy; Michael Mullendore; Malte Buchholz; Anirban Maitra; Georg Feldmann

2007-01-01

405

Removal of corallivorous snails as a proactive tool for the conservation of acroporid corals  

PubMed Central

Corallivorous snail feeding is a common source of tissue loss for the threatened coral, Acropora palmata, accounting for roughly one-quarter of tissue loss in monitored study plots over seven years. In contrast with larger threats such as bleaching, disease, or storms, corallivory by Coralliophila abbreviata is one of the few direct sources of partial mortality that may be locally managed. We conducted a field experiment to explore the effectiveness and feasibility of snail removal. Long-term monitoring plots on six reefs in the upper Florida Keys were assigned to one of three removal treatments: (1) removal from A. palmata only, (2) removal from all host coral species, or (3) no-removal controls. During the initial removal in June 2011, 436 snails were removed from twelve 150 m2 plots. Snails were removed three additional times during a seven month “removal phase”, then counted at five surveys over the next 19 months to track recolonization. At the conclusion, snails were collected, measured and sexed. Before-After-Control-Impact analysis revealed that both snail abundance and feeding scar prevalence were reduced in removal treatments compared to the control, but there was no difference between removal treatments. Recolonization by snails to baseline abundance is estimated to be 3.7 years and did not differ between removal treatments. Recolonization rate was significantly correlated with baseline snail abundance. Maximum snail size decreased from 47.0 mm to 34.6 mm in the removal treatments. The effort required to remove snails from A. palmata was 30 diver minutes per 150 m2 plot, compared with 51 min to remove snails from all host corals. Since there was no additional benefit observed with removing snails from all host species, removals can be more efficiently focused on only A. palmata colonies and in areas where C. abbreviata abundance is high, to effectively conserve A. palmata in targeted areas. PMID:25469321

Miller, Margaret W.; Bright, Allan J.; Cameron, Caitlin M.

2014-01-01

406

The role of the transcriptional regulator snail in cell detachment, reattachment and migration  

PubMed Central

In order to metastasize, cancer cells must first detach from the primary tumor, migrate, invade through tissues and attach to a second site. The transcription factor snail is an important mediator of epithelial-mesenchymal transitions and is involved in tumor progression. Recent data have provided evidence for a requirement for snail expression in metastatic dissemination. Although very little is known about the molecular mechanisms governing metastatic dissemination, we review the possible roles of snail expression in this process. We also review the regulation of snail expression. PMID:19287205

2009-01-01

407

Sexual selection maintains whole-body chiral dimorphism in snails  

PubMed Central

Although the vast majority of higher animals are fixed for one chiral morph or another, the cause for this directionality is known in only a few cases. In snails, for example, rare individuals of the opposite coil are unable to mate with individuals of normal coil, so directionality is maintained by frequency-dependent selection. The snail subgenus Amphidromus presents an unexplained exception, because dextral (D) and sinistral (S) individuals occur sympatrically in roughly equal proportions (so-called ‘antisymmetry’) in most species. Here we show that in Amphidromus there is sexual selection for dimorphism, rather than selection for monomorphism. We found that matings between D and S individuals occur more frequently than expected by chance. Anatomical investigations showed that the chirality of the spermatophore and the female reproductive tract probably allow a greater fecundity in such inter-chiral matings. Computer simulation confirms that under these circumstances, sustained dimorphism is the expected outcome. PMID:17714311

SCHILTHUIZEN, M.; CRAZE, P. G.; CABANBAN, A. S.; DAVISON, A.; STONE, J.; GITTENBERGER, E.; SCOTT, B. J.

2007-01-01

408

Sexual selection maintains whole-body chiral dimorphism in snails.  

PubMed

Although the vast majority of higher animals are fixed for one chiral morph or another, the cause for this directionality is known in only a few cases. In snails, for example, rare individuals of the opposite coil are unable to mate with individuals of normal coil, so directionality is maintained by frequency-dependent selection. The snail subgenus Amphidromus presents an unexplained exception, because dextral (D) and sinistral (S) individuals occur sympatrically in roughly equal proportions (so-called 'antisymmetry') in most species. Here we show that in Amphidromus there is sexual selection for dimorphism, rather than selection for monomorphism. We found that matings between D and S individuals occur more frequently than expected by chance. Anatomical investigations showed that the chirality of the spermatophore and the female reproductive tract probably allow a greater fecundity in such inter-chiral matings. Computer simulation confirms that under these circumstances, sustained dimorphism is the expected outcome. PMID:17714311

Schilthuizen, M; Craze, P G; Cabanban, A S; Davison, A; Stone, J; Gittenberger, E; Scott, B J

2007-09-01

409

Mercury residues in south Florida apple snails (Pomacea paludosa)  

SciTech Connect

Mercury concentrations in the sediments of south Florida wetlands have increased three fold in the last century. Because south Florida is home to many endemic and endangered species, it is important to understand the potential impacts of mercury in this ecosystem`s food web. Recent research by Malley et al. has shown mollusks to be sensitive indicators of methyl mercury which can reflect small differences in background methyl mercury concentrations. In this study, we attempted to determine if the apple snail (Pomacea paludosa) or its eggs are good indicators of bioavailable mercury. Then, using the apple snail as an indicator, we attempted to determine geographic differences in the concentrations of mercury in south Florida. 12 refs., 1 fig., 1 tab.

Eisemann, J.D.; Beyer, W.N.; Morton, A. [National Biological Services, Laurel, MD (United States)] [National Biological Services, Laurel, MD (United States); Bennetts, R.E. [Univ. of Florida, Gainesville, FL (United States)] [Univ. of Florida, Gainesville, FL (United States)

1997-05-01

410

Mercury residues in south Florida apple snails (Pomacea paludosa)  

USGS Publications Warehouse

Mercury concentrations in the sediments of south Florida wetlands have increased three fold in the last century (Rood et al. 1993). Because south Florida is home to many endemic and endangered species, it is important to understand the potential impacts of mercury in this ecosystem's food web. Recent research by Malley et al. (1996) has shown mollusks to be sensitive indicators of methyl mercury which can reflect small differences in background methyl mercury concentrations. In this study, we attempted to determine if the apple snail (Pomacea paludosa) or its eggs are good indicators of bioavailable mercury. Then, using the apple snail as an indicator, we attempted to determine geographic differences in the concentrations of mercury in south Florida.

Eisemann, J.D.; Beyer, W.N.; Bennetts, R.E.; Morton, A.

1997-01-01

411

Neurohormonal control of cardiac activity in the snail, Helix aspersa  

Microsoft Academic Search

1.The characteristics of a cardioactive peptide(s), LCP, were investigated in the snail,Helix aspersa, to determine if LCP functions as a neurohormone.2.Fractionation of isotonic homogenates of the auricle and sub-esophageal ganglia indicate that LCP is associated with microsomal elements, probably granules observed in electron micrographs of the microsomal pellets.3.Ligation experiments carried out under culture conditions suggest that LCP is transported from

Philip E. Lloyd

1978-01-01

412

Functional Changes in the Snail Statocyst System Elicited by Microgravity  

Microsoft Academic Search

BackgroundThe mollusk statocyst is a mechanosensing organ detecting the animal's orientation with respect to gravity. This system has clear similarities to its vertebrate counterparts: a weight-lending mass, an epithelial layer containing small supporting cells and the large sensory hair cells, and an output eliciting compensatory body reflexes to perturbations.Methodology\\/Principal FindingsIn terrestrial gastropod snail we studied the impact of 16- (Foton

Pavel M. Balaban; Aleksey Y. Malyshev; Victor N. Ierusalimsky; Nikolay Aseyev; Tania A. Korshunova; Natasha I. Bravarenko; M. S. Lemak; Matvey Roshchin; Igor S. Zakharov; Yekaterina Popova; Richard Boyle; Hiromu Tanimoto

2011-01-01

413

Effect of Glyphosate on the Development of Pseudosuccinea columella Snails  

Microsoft Academic Search

.   Glyphosate (Roundup) is one of the most commonly used broad-spectrum herbicides with little to no hazard to animals, man,\\u000a or the environment. Due to its widespread use, there is continuous contamination of the environment in both soil and water\\u000a with this herbicide. There is a paucity of long-term exposure studies with sublethal concentrations of glyphosate on aquatic\\u000a snails. This

T. M. Tate; J. O. Spurlock; F. A. Christian

1997-01-01

414

Supplementary Information Species Optimal N:P Freshwater/ Taxon Source  

E-print Network

Cyanobacterium 8 Heterosigma akashiwo 13.1 Marine Rhaphydophyte 9 Anabaena solitaria 14.0 Freshwater Coccolithophorid 11 Oscillatoria redekei 17.1 Freshwater Cyanobacterium 8 Anabaena flos-aquae 17.7 Freshwater

415

Fish Grubs in Freshwater Ponds and Lakes.  

E-print Network

not only the fish but also a snail and a bird. The cycle begins in the water with the hatching *Extension fish disease specialist. The Texas A&M University System. and release of a stage known as a miracidium from the microscopic-size egg (figure 1... ). Figure 1. Miracidium hatches from egg and begins search for a snail. The miracidium, whose length is greater than its width, is propelled by the movement of cilia (hair-like structures) on the body surface. After a few hours of swimming...

Johnson, Sterling K.

1981-01-01

416

Phenoloxidase activity of Helix aspersa maxima (garden snail, gastropod) hemocyanin.  

PubMed

The oxygen-transporting protein, hemocyanin (Hc), of the garden snail Helix aspersa maxima (HaH) was isolated and kinetically characterized. Kinetic parameters of the reaction of catalytic oxidation of catechol to quinone, catalyzed by native HaH were determined: the V max value amounted to 22 nmol min(-1) mg(-1), k cat to 1.1 min(-1). Data were compared to those reported for other molluscan Hcs and phenoloxidases (POs). The o-diphenoloxidase activity of the native HaH is about five times higher than the activity determined for the Hcs of the terrestrial snail Helix pomatia and of the marine snail Rapana thomasiana (k cat values of 0.22 and 0.25 min(-1), respectively). The K m values obtained for molluscan Hcs from different species are comparable to those for true POs, but the low catalytic efficiency of Hcs is probably related to inaccessibility of the active sites to potential substrates. Upon treatment of HaH with subtilisin DY, the enzyme activity against substrate catechol was considerably increased. The relatively high proteolytically induced o-diPO activity of HaH allowed using it for preparation of a biosensor for detection of catechol. PMID:24243490

Raynova, Yuliana; Doumanova, Lyuba; Idakieva, Krassimira Nikolova

2013-12-01

417

Human Freshwater Demand for Economic Activity and Ecosystems in Taiwan  

Microsoft Academic Search

Freshwater is necessary to economic activity, and humans depend on goods and services generated by water-dependent ecosystems.\\u000a However, national freshwater management usually focuses on direct use of domestic freshwater. With an increasing scarcity\\u000a of freshwater, attention has turned to two indirect uses of freshwater by humans. The first indirect use is freshwater used\\u000a by foreign countries when producing products for

Jiun-Jiun Ferng

2007-01-01

418

Occurrence of a blood group A-like substance in eggs of the prosobranch snail Pomacea canaliculata.  

PubMed

In the eggs of the prosobranch snails Pomacea canaliculata and Pomacea insularum a blood group A-like substance has been detected by anti-A from the snails Helix pomatia, Helix aspersa and Cepaea nemoralis. PMID:815102

Uhlenbruck, G; Steinhausen, G; Cheesman, D F; Helm, B

1976-03-15

419

THE BIOCIDE TRIBUTYLTIN REDUCES THE ACCUMULATION OF TESTOSTERONE AS FATTY ACID ESTERS IN THE MUD SNAIL (ILYANASSA OBSOLETA)  

EPA Science Inventory

Imposex, the development of male sex characteristics by female gonochoristic snails, has been documented globally and is causally associated with exposure to the ubiquitous environmental contaminant tributyltin (TBT). Elevated testosterone levels in snails also are associated wit...

420

Field prevalence and laboratory susceptibility of southern Australian land snails to Brachylaima cribbi sporocyst infection.  

PubMed

Brachylaima cribbi is a terrestrial trematode of birds and mammals with helicid and hygromiid land snails reported as first and second intermediate hosts. However, reports describing the first intermediate host range of B. cribbi have been limited to those snail species present in a small number of geographical locations in South Australia. The natural first intermediate host range, distribution and prevalence of B. cribbi in land snails in southern Australia were determined. A total of 6,432 introduced and native land snails were collected from eight geographical districts across 3,000 km of southern Australia and examined microscopically for B. cribbi sporocysts. Four introduced European snails, Theba pisana, Cernuella virgata, Cochlicella acuta and Cochlicella barbara were natural first intermediate hosts. Sporocyst-infected snails were detected in all districts from Victoria to the west coast of South Australia, a distance of over 1,300 km. Natural sporocyst infection was not observed in introduced European snails Microxeromagna armillata and Helix aspersa or in native Australian land snails Succinea australis and Strangesta gawleri. Egg feeding experiments in the laboratory with B. cribbi confirmed the susceptibility of those species of snails found to be natural first intermediate hosts. Of those species not found to be infected in nature, only M. armillata could be infected in the laboratory. Although this study has shown that five different species of European land snails are suitable first intermediate hosts for B. cribbi there are as yet no reports of B. cribbi from these snails in Europe or from other countries where they have been introduced. Further investigations are needed in Europe to clarify the origins of this parasite. PMID:12847918

Butcher, A R; Grove, D I

2003-06-01

421

Uranium bioaccumulation in a freshwater ecosystem: impact of feeding ecology.  

PubMed

The objectives of our study were: (1) to determine if there was significant uranium (U) bioaccumulation in a lake that had been historically affected by a U mine and (2) to use a combined approach of gut content examination and stable nitrogen and carbon isotope analysis to determine if U bioaccumulation in fish was linked to foodweb ecology. We collected three species of fish: smallmouth bass (Micropterus dolomieu), yellow perch (Perca flavescens) and bluegill (Lepomis macrochirus), in addition to several invertebrate species including freshwater bivalves (family: Sphaeriidae), dragonfly nymphs (order: Odonata), snails (class: Gastropoda) and zooplankton (family: Daphniidae). Results showed significant U bioaccumulation in the lake impacted by historical mining activities. Uranium accumulation was 2-3 orders of magnitude higher in invertebrates than in the fish species. Within fish, U was measured in operculum (bone), liver and muscle tissue and accumulation followed the order: operculum>liver>muscle. There was a negative relationship between stable nitrogen ratios ((15)N/(14)N) and U bioaccumulation, suggesting U biodilution in the foodweb. Uranium bioaccumulation in all three tissues (bone, liver, muscle) varied among fish species in a consistent manner and followed the order: bluegill>yellow perch>smallmouth bass. Collectively, gut content and stable isotope analysis suggests that invertebrate-consuming fish species (i.e. bluegill) have the highest U levels, while fish species that were mainly piscivores (i.e. smallmouth bass) have the lowest U levels. Our study highlights the importance of understanding the feeding ecology of fish when trying to predict U accumulation. PMID:22963859

Kraemer, Lisa D; Evans, Douglas

2012-11-15

422

The effect of isolation on reproduction and growth of Pseudosuccinea columella (Pulmonata: Lymnaeidae): a snail-conditioned water experiment.  

PubMed

A snail-conditioned water experiment was conducted in Pseudosuccinea columella to test the possible role of a chemical interaction between snails on the diminished growth and fecundity rates found for snails raised in pairs compared to those raised in complete isolation. The results permit to discard the hypothesis of an inhibition of growth and reproduction b