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1

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

PubMed

Several recent studies have demonstrated that the freshwater pulmonate snail Lymnaea stagnalis is extremely sensitive to metals (Co, Ni, Pb) in chronic exposures. The objective of the current study was to evaluate the acute and chronic sensitivity of L. stagnalis to Cu and investigate the underlying mechanism(s) of toxic action. A 96-h LC50 of 31?g L(-1) Cu was estimated indicating L. stagnalis was moderately acutely sensitive to Cu relative to other aquatic organisms. However, in a 30-day chronic exposure using juvenile snails an EC20 of 1.8?g L(-1) Cu was estimated for snail growth making L. stagnalis the most sensitive organism tested to date for Cu. Hardness-based and BLM-based water quality criteria for Cu at the water quality conditions used in this study were 7.8 and 1.5?g L(-1), respectively, indicating L. stagnalis is significantly under-protected by hardness-based WQC. Investigations into the mechanism(s) of toxic action for Cu were conducted on young adult snails necessitating higher Cu exposures. Exposure to Cu at 12?g L(-1) resulted in no detectable effects on hemolymph osmolality, net Ca(2+) uptake, titratable acid excretion, or ammonia excretion. Exposure to 48?g L(-1) Cu was shown to significantly reduce (91%) net Ca(2+) uptake which is strongly correlated with shell deposition and corresponding snail growth. Snails exposed to 48?g L(-1) Cu also exhibited reduced ammonia excretion, a marked hemolymph acidosis, and a compensatory increase in titratable acid excretion. The reduction in net Ca(2+) uptake was hypothesized to be a secondary effect of Cu-induced inhibition of carbonic anhydrase, but no reduction in carbonic anhydrase activity was detected. Overall, it remains unclear whether inhibition of Ca(2+) uptake is a direct result of Cu exposure or, along with the other observed physiological effects, is secondary to an unidentified primary mode of toxic action. Given the hypersensitivity of L. stagnalis to Cu, further study into the mechanisms of action and effects of varying water chemistry on Cu toxicity is clearly warranted. PMID:21723419

Brix, Kevin V; Esbaugh, Andrew J; Grosell, Martin

2011-09-01

2

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

3

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

4

THE SOUTHWESTERN NATURALIST 50(4):415422 DECEMBER 2005 NO REPRODUCTIVE ISOLATION BETWEEN FRESHWATER PULMONATE  

E-print Network

FRESHWATER PULMONATE SNAILS PHYSA VIRGATA AND P. ACUTA ROBERT T. DILLON, JR.,* JOHN D. ROBINSON, THOMAS P River of Arizona and Physa acuta (Draparnaud, 1805) from a control site in Charleston, South Carolina of the cosmopolitan P. acuta. RESUMEN Pruebas de la eleccio´n de pareja no proveyeron ninguna evidencia de aislamiento

Dillon, Robert T.

5

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

6

Predator-induced life-history shifts in a freshwater snail.  

PubMed

The snail Physella virgata virgata, a widely distributed freshwater pulmonate, was observed to change its life-history characteristics in the presence of the crayfish Orconectes virilis in spring-fed Oklahoma streams. These changes were apparently initiated by a water-borne cue released when crayfish fed on conspecific snails. In the presence of the cue, snails exhibited rapid growth rates and little reproduction until they reached a size of about 10 mm after 8 months. In the absence of the cue, snails typically grew to about 4 mm (3.5 months) and then began reproduction. The chemically inducible shift indicates that the life histories of these snails are phenotypically plastic. By increasing the variance associated with size and age of maturity, prey may increase the likelihood of coexisting with seasonal predators. PMID:17776452

Crowl, T A; Covich, A P

1990-02-23

7

EMPIRICAL ESTIMATES OF REPRODUCTIVE ISOLATION AMONG THE FRESHWATER PULMONATE SNAILS  

E-print Network

are distinct biological species. Key words: Gastropoda, Pulmonata, Physella, speciation, mate choice, allozyme all be junior synonyms of P. gyrina (Dillon & Wethington, 2006a, b). Reproductive isolation seems

Dillon, Robert T.

8

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

9

Predation Risk and Avoidance Behavior in Two Freshwater Snails  

Microsoft Academic Search

We examined the predator avoidance behav- iors of two common freshwater snails, Physella virgata and Planorbella trivolvis, to the crayfish Procambarus simulans. In response to crayfish predation, the snails crawled above the waterline for several hours, then re- turned to the water. A significant size-dependent rela- tionship existed between crawlout (vertical migration above the waterline) and vulnerability to predation. All

JAMES E. ALEXANDER; ALAN P. COVICH

1991-01-01

10

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

11

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

2014-11-18

12

Comparative Neurobiology of Feeding in the Opisthobranch Sea Slug, Aplysia, and the Pulmonate Snail, Helisoma: Evolutionary Considerations  

PubMed Central

The motor systems that generate feeding-related behaviors of gastropod mollusks provide exceptional opportunities for increasing our understanding of neural homologies and the evolution of neural networks. This report examines the neural control of feeding in Helisoma trivolvis, a pulmonate snail that ingests food by rasping or scraping material from the substrate, and Aplysia californica, an opisthobranch sea slug that feeds by using a grasping or seizing motion. Two classes of neurons that are present in the buccal ganglia of both species are considered: (1) clusters of peptidergic mechanoafferent cells that transmit sensory information from the tongue-like radula/odontophore complex to the central motor circuit; and (2) sets of octopamine-immunoreactive interneurons that are intrinsic to the feeding network. We review evidence that suggests homology of these cell types and propose that their roles have been largely conserved in the control of food-scraping and food-grasping consummatory behaviors. We also consider significant differences in the feeding systems of Aplysia and Helisoma that are associated with the existence of radular closure in Aplysia, an action that does not occur in Helisoma. It is hypothesized that a major adaptation in the innervation patterns of analogous, possibly homologous muscles could distinguish the food-scraping versus food-grasping species. It appears that although core CPG elements have been largely conserved in this system, the neuromuscular elements that they regulate have been more evolutionarily labile. PMID:20029185

Wentzell, Margaret M.; Martínez-Rubio, Clarissa; Miller, Mark W.; Murphy, A. Don

2009-01-01

13

Habitat disturbance and the stability of freshwater gastropod populations  

Microsoft Academic Search

The interaction of population stability and habitat permanence has a major influence on the microdistribution of freshwater snails. For two years (February 1980–January 1982), we monitored the abundance of macrophytes and the abundance and size structure of four species of macrophyte-associated freshwater snails in an English pond. Previous work (Lodge, in press) showed that two species, the pulmonate Lymnaea peregra

D. M. Lodge; P. Kelly

1985-01-01

14

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

15

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...

16

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

17

Foraging trade-offs and resource patchiness: theory and experiments with a freshwater snail community  

Microsoft Academic Search

Empirical results concerning a freshwater snail community are interpreted using a two- species consumer model that incorporates resource structure. Behavioural-scale measurements on a guild of five species of freshwater pond snails (Mollusca: Pulmonata) indicate a trade-off between the ability to utilize a patch's resource and the ability to quickly find new resource patches. Community-level experiments demonstrate that both species richness

Jonathan M. Chase; Will G. Wilson; Shane A. Richards

2001-01-01

18

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

19

Isolation of salmonellae and other potential pathogens from the freshwater aquarium snail Ampullaria.  

PubMed Central

The freshwater aquarium snail (Ampullaria spp.) was demonstrated to carry as many as 10(8) viable mesophilic bacteria per g of meat plus shell. Some 16 genera of bacteria were identified, with gram negatives predominating. Enrichment culture techniques enabled the isolation of salmonellae from 24 to 42 lots of 200 g each. The salmonellae comprised eight different serotypes, including Salmonella newport, Salmonella saint-paul, and Salmonella infantis. This association of salmonellae with snails may contribute to cases of human salmonellosis, since other aquarium species have already been shown to contribute to many such cases. The snails were also found to commonly harbor Pseudomonas aeruginosa and, occasionally, Edwardsiella tarda. PMID:818954

Bartlett, K H; Trust, T J

1976-01-01

20

Snail Snooping.  

ERIC Educational Resources Information Center

Presents an activity in which students in grades 5-8 learn about snail reproduction by observing and charting the activities of land snails, freshwater snails, and slugs. Instructions to implement and extend the activity are provided. (MDH)

Miller, Dorothy

1993-01-01

21

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

22

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

23

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

24

Competitive interactions between two successful molluscan invaders of freshwaters: an experimental study  

Microsoft Academic Search

The New Zealand mud snail Potamopyrgus antipodarum (Hydrobiidae) and the pulmonate Physella acuta (Physidae) have invaded freshwaters in many parts of the world and become established. They co-exist in many streams, lakes and ponds in New Zealand, often at high densities. In the present study the effects of intraspecific- and interspecific interactions between the two species on growth and reproductive

Neisha J. Cope; Michael J. Winterbourn

2004-01-01

25

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

26

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

27

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

PubMed

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

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

2011-12-01

28

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

PubMed Central

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

2014-01-01

29

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

30

Habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus (Müller, 1774).  

PubMed

Our objective is to evaluate the habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus. In the first phase, snails was collected at 12 sites. This sampling sites presented a degree of organic input. In the second phase 33 sampling sites were chosen, covering a variety of lotic and lentic environments. The snail species found at Guapimirim, state of Rio de Janeiro, displayed a marked habitat preference, specially in relation to the physical characteristics of each environment. Other limiting factors for snail distribution at the studied lotic environments were the water current velocity and the amount of organic matter, mainly to Physa marmorata, M. tuberculatus, and Biomphalaria tenagophila. The absence of interactions between M. tuberculatus and another snails could be associated to the distinct spatial distribution of those species and the instability of habitats. This later factor may favor the coexistence of M. tuberculatus with B. glabrata by reduction of population density. In areas of schistosomiasis transmission some habitat modification may add to the instability of the environment, which would make room for the coexistence of M. tuberculatus and Biomphalaria spp. In this way, some of the usual measures for the control of snail hosts would prevent the extinction of populations of Biomphalaria spp. by M. tuberculatus in particular habitats. PMID:16021304

Giovanelli, Alexandre; da Silva, Cesar Luiz Pinto Ayres Coelho; Leal, Geórgia Borges Eccard; Baptista, Darcílio Fernandes

2005-04-01

31

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

32

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

33

Microsatellites and the Genetics of Highly Selfing Populations in the Freshwater Snail Bulinus Truncatus  

PubMed Central

Hermaphrodite tropical freshwater snails provide a good opportunity to study the effects of mating system and genetic drift on population genetic structure because they are self-fertile and they occupy transient patchily distributed habitats (ponds). Up to now the lack of detectable allozyme polymorphism prevented any intrapopulation studies. In this paper, we examine the consequences of selfing and bottlenecks on genetic polymorphism using microsatellite markers in 14 natural populations (under a hierarchical sampling design) of the hermaphrodite freshwater snail Bulinus truncatus. These population genetics data allowed us to discuss the currently available mutation models for microsatellite sequences. Microsatellite markers revealed an unexpectedly high levels of genetic variation with <=41 alleles for one locus and gene diversity of 0.20-0.75 among populations. The values of any estimator of F(is) indicate high selfing rates in all populations. Linkage disequilibria observed at all loci for some populations may also indicate high levels of inbreeding. The large extent of genetic differentiation measured by F(st), R(st) or by a test for homogeneity between genic distributions is explained by both selfing and bottlenecks. Despite a limited gene flow, migration events could be detected when comparing different populations within ponds. PMID:8846901

Viard, F.; Bremond, P.; Labbo, R.; Justy, F.; Delay, B.; Jarne, P.

1996-01-01

34

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

35

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

Microsoft Academic Search

We collected six species of freshwater snails from Dominica, including Biomphalaria kuhniana (Clessin, 1883), Gundlachia radiata (Guilding, 1828), Helisoma (=Planorbella) trivolvis (Say, 1817), Melanoides tuberculata (Müller, 1774), Neritina punctulata Lamarck, 1816, and Physa marmorata Guilding, 1828. Our collections indicate that un-reported species such as G. radiata and H. trivolvis are established on Dominica, West Indies. We tested a limited number

Will K. Reeves; Robert T. Dillon; Gregory A. Dasch

2008-01-01

36

Response to phosphorus limitation varies among lake populations of the freshwater snail Potamopyrgus antipodarum.  

PubMed

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

37

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

38

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

39

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

40

Studies on the morphology of cercariae obtained from freshwater snails at Erawan Waterfall, Erawan National Park, Thailand.  

PubMed

The morphology of cercariae of freshwater snails from Erawan Waterfall, Erawan National Park, Kanchanaburi Province was studied between December 2002 and August 2003. The snail samples were collected by handpicking using a counts per unit of time sampling method. The cercariae, larva stage of a trematode, were investigated using the shedding method where they were categorized into three groups and six species. The first group, Pleurolophocercous cercariae, consists of Haplorchis pumillo (C1) and Stictodora tridactyla (C3). The second group, Furcocercous cercariae, consisted of Mesostephanus appendicalatus (C2), Transversotrema laruei (C6) and Cardicola alseae(C4). The third group, Xiphidio cercariae, has only one species which is Loxogenoides bicolor (C5). Out of 1163 snails, only 62 were found to be infected by cercariae, equivalent to a 5.33% infection rate. The infections grouped by species of the cercariae are as follows: C, 22 (1.9%), C, 29 (2.5%), C2 1 (0.1%), C6 1 (0.1%), C4 6 (0.5%) and C5 3 (0.3%). The freshwater snail samples consist of four species. From a total of 1163 samples, there are 687 Melanoides jugicostis, 91 Tarebia granifera, 296 Thiara scabra and 89 Melanoides tuberculata. Infections were found in 45 (6.5%), 6 (6.6%), 1 (0.3%) and 10 (11.2%), respectively. PMID:17539280

Ukong, Suluck; Krailas, Duangduen; Dangprasert, Tunyarut; Channgarm, Pasapong

2007-03-01

41

Parental exposure to pesticides and progeny reaction norm to a biotic stress gradient in the freshwater snail Lymnaea stagnalis  

Microsoft Academic Search

Human-induced environmental stress may lead to rapid evolutionary processes, and can affect the ability of natural populations\\u000a to respond to other environmental change or stress. We used quantitative genetics tools, pesticide exposure and a gradient\\u000a of biotic stress to investigate these questions in the freshwater snail Lymnaea stagnalis. The study focused on the genetic component of variance for life-history traits

Marie-Agnès Coutellec; Marc Collinet; Thierry Caquet

2011-01-01

42

Characterizing a hybrid zone between a cryptic species pair of freshwater snails.  

PubMed

Characterizing hybrid zones and their dynamics is a central goal in evolutionary biology, but this is particularly challenging for morphologically cryptic species. The lack of conspicuous divergence between parental types means intermediate hybrid forms often go undetected. We aimed to detect and characterize a suspected hybrid zone between a pair of morphologically cryptic lineages of the freshwater snail, Radix. We sampled Radix from across a contact zone between two mitochondrial lineages (Radix balthica and an undescribed lineage termed 'MOTU3') and detected admixture between two nuclear genotype clusters, which were significantly but not categorically associated with the mitochondrial lineages. Using a model selection approach, we show that the admixture cline is best explained by an interaction between precipitation and temperature gradients over the area, rather than geographic distance. We thus hypothesize that the correlation with climatic gradients suggests environmental selection has played a role in maintaining the hybrid zone. In a 2050 climate change scenario, we furthermore predict an expansion of one of the nuclear clusters and a widening of the hybrid zone as the climate warms and dries. PMID:25533031

Patel, Simit; Schell, Tilman; Eifert, Constanze; Feldmeyer, Barbara; Pfenninger, Markus

2015-02-01

43

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

44

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

45

Spermatozoa Production by Triploid Males in the New Zealand Freshwater Snail Potamopyrgus antipodarum  

PubMed Central

Asexual lineages derived from dioecious taxa are typically assumed to be all female. Even so, asexual females from a variety of animal taxa occasionally produce males. The existence of these males sets the stage for potential gene flow across asexual lineages as well as between sexual and asexual lineages. A recent study showed that asexual triploid female Potamopyrgus antipodarum, a New Zealand freshwater snail often used as a model to study sexual reproduction, occasionally produce triploid male offspring. Here, we show that these triploid male P. antipodarum 1) have testes that produce morphologically normal sperm, 2) make larger sperm cells that contain more nuclear DNA than the sperm produced by diploid sexual males, and 3) produce sperm that range in DNA content from haploid to diploid, and are often aneuploid. Analysis of meiotic chromosomes of triploid males showed that aberrant pairing during prophase I likely accounts for the high variation in DNA content among sperm. These results indicate that triploid male P. antipodarum produce sperm, but the extent to which these sperm are able to fertilize female ova remains unclear. Our results also suggest that the general assumption of sterility in triploid males should be more closely examined in other species in which such males are occasionally produced. PMID:24307744

Soper, D.M.; Neiman, M.; Savytskyy, O.P.; Zolan, M.E.; Lively, C.M.

2013-01-01

46

Spermatozoa Production by Triploid Males in the New Zealand Freshwater Snail Potamopyrgus antipodarum.  

PubMed

Asexual lineages derived from dioecious taxa are typically assumed to be all female. Even so, asexual females from a variety of animal taxa occasionally produce males. The existence of these males sets the stage for potential gene flow across asexual lineages as well as between sexual and asexual lineages. A recent study showed that asexual triploid female Potamopyrgus antipodarum, a New Zealand freshwater snail often used as a model to study sexual reproduction, occasionally produce triploid male offspring. Here, we show that these triploid male P. antipodarum 1) have testes that produce morphologically normal sperm, 2) make larger sperm cells that contain more nuclear DNA than the sperm produced by diploid sexual males, and 3) produce sperm that range in DNA content from haploid to diploid, and are often aneuploid. Analysis of meiotic chromosomes of triploid males showed that aberrant pairing during prophase I likely accounts for the high variation in DNA content among sperm. These results indicate that triploid male P. antipodarum produce sperm, but the extent to which these sperm are able to fertilize female ova remains unclear. Our results also suggest that the general assumption of sterility in triploid males should be more closely examined in other species in which such males are occasionally produced. PMID:24307744

Soper, D M; Neiman, M; Savytskyy, O P; Zolan, M E; Lively, C M

2013-09-01

47

Genetic diversity, fixation and differentiation of the freshwater snail Biomphalaria pfeifferi (Gastropoda, Planorbidae) in arid lands.  

PubMed

The freshwater snail Biomphalaria pfeifferi is the main intermediate host of human intestinal Bilharziasis. It is widely distributed in Africa, Madagascar and middle-eastern countries, and its habitat includes wetlands, and arid to semi-arid areas. Based on analysis of 18 microsatellites, we investigated reference allelic variation among 30 populations of B. pfeifferi from three drainage basins in Dhofar, Oman (the eastern limit of its distribution). This is an arid to semi-arid region, with a 9,000-year history of very low rainfall, but is subject to unpredictable and destructive flash floods. In this context we showed that genetic fixation was very high compared to genetic differentiation which was moderate and, that, relative to B. pfeifferi populations from wetlands, the populations in Dhofar show evidence of lower levels of genetic diversity, a higher degree of genetic fixation, a quasi-absence of migration, and a higher level of genetic drift. Despite the extreme conditions in the Dhofar habitat of this species, it is able to survive because of its very high self-fertilization (approaching 100 %) and fecundity rates. PMID:23543205

Mintsa Nguema, Rodrigue; Langand, Juliette; Galinier, Richard; Idris, Mohamed A; Shaban, Mahmoud A; Al Yafae, Salem; Moné, Hélène; Mouahid, Gabriel

2013-06-01

48

Profound Effects of Population Density on Fitness-Related Traits in an Invasive Freshwater Snail  

PubMed Central

Population density can profoundly influence fitness-related traits and population dynamics, and density dependence plays a key role in many prominent ecological and evolutionary hypotheses. Here, we evaluated how individual-level changes in population density affect growth rate and embryo production early in reproductive maturity in two different asexual lineages of Potamopyrgus antipodarum, a New Zealand freshwater snail that is an important model system for ecotoxicology and the evolution of sexual reproduction as well as a potentially destructive worldwide invader. We showed that population density had a major influence on individual growth rate and early-maturity embryo production, effects that were often apparent even when comparing treatments that differed in population density by only one individual. While individual growth rate generally decreased as population density increased, we detected a hump-shaped relationship between embryo production and density, with females from intermediate-density treatments producing the most embryos and females from low- and high-density treatments producing the fewest embryos. The two lineages responded similarly to the treatments, indicating that these effects of population density might apply more broadly across P. antipodarum. These results indicate that there are profound and complex relationships between population density, growth rate, and early-maturity embryo production in at least two lineages of this important model system, with potential implications for the study of invasive populations, research on the maintenance of sex, and approaches used in ecotoxicology. PMID:24278240

Zachar, Nicholas; Neiman, Maurine

2013-01-01

49

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

50

Molecular evolution of freshwater snail intermediate hosts within the Bulinus forskalii group.  

PubMed

Freshwater snails of the Bulinus forskalii group are one of four Bulinus species complexes responsible for the transmission of schistosomes in Africa and adjacent regions. The species status of these conchologically variable and widely distributed planorbids remains unclear, and parasite compatibility varies considerably amongst the eleven taxa defined, making unambiguous identification and differentiation important prerequisites for determining their distributions and evolutionary relationships. Random Amplified Polymorphic DNA (RAPD) analyses were used to investigate relationships between taxa, with particular emphasis on Central and West African representatives. RAPD-derived phylogenies were compared with those from other independent molecular markers, including partial sequences of mitochondrial cytochrome oxidase subunit I (COI) gene, and the nuclear ribosomal RNA internal transcribed spacer 1 region (ITS1). The phylogenetic reconstructions from the three approaches were essentially congruent, in that all methods of analysis gave unstable tree topologies or largely unresolved branches. There were large sequence divergence estimates between species, with few characters useful for determining relationships between species and limited within species differentiation. Nuclear and mtDNA sequence data from Central and East African representatives of the pan-African B. forskalii showed little evidence of geographical structuring. Despite the unresolved structure within the phylogenies, specimens from the same species clustered together indicating that all methods were capable of differentiating taxa but could not establish the inter-specific relationships with confidence. The limited genetic variation displayed by B. forskalii, and the evolution and speciose nature of the group, are discussed in the context of the increasingly arid climate of the late Miocene and early Pliocene of Africa. PMID:11769290

Jones, C S; Rollinson, D; Mimpfoundi, R; Ouma, J; Kariuki, H C; Noble, L R

2001-01-01

51

Larval stages of digenetic trematodes in Melanopsis praemorsa snails from freshwater bodies in Palestine  

PubMed Central

Objective To detect the species of larval trematodes (cercariae) in Melanopsis praemorsa snails from 5 different fresh water bodies in Palestine. Methods A total of 1 880 Melanopsis praemorsa snails were collected from different fresh water bodies in Palestine from October, 2008 to November, 2010. Cercariae in Melanopsis praemorsa snails were obtained by lighting and crushing methods. The behavior of cercariae was observed using a dissecting microscope. Results Three different species of larval trematodes were identified from Melanopsis praemorsa snails collected only from Al-Bathan fresh water body, while snails from other water bodies were not infected. These species were microcercous cercaria, xiphidiocercaria and brevifurcate lophocercous cercaria. These cercariae called Cercaria melanopsi palestinia I, Cercaria melanopsi palestinia II and Cercaria melanopsi palestinia III have not been described before from this snail in Palestine. The infection rate of Melanopsis praemorsa collected from Al-Bathan fresh water body was 5.7%, while the overall infection rate of snails collected from all fresh water bodies was 4.3%. Details are presented on the morphology and behavior of the cercariae as well as their development within the snail. Conclusions These results have been recorded for the first time and these cercariae may be of medical and veterinary importance. PMID:23569759

Bdir, Sami; Adwan, Ghaleb

2011-01-01

52

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

53

Does social facilitation affect responses to natural and anthropogenic stressors in the freshwater snail Planorbella trivolvis?  

PubMed

Social facilitation is the initiation or increase of a trait, such as stressor tolerance, when in the presence of conspecifics, members of the same species. It has been shown to alter the outcome of toxicity experiments in colonial organisms. We evaluated whether social facilitation would impact responses to stressors in the noncolonial New Mexico ramshorn snail (Planorbella trivolvis) by exposing snails to stressors either singly or in groups of three. Social facilitation did not impact snail responses to malathion but did affect responses to predator cues and temperature stress. PMID:21935982

Plautz, Stephanie C; Salice, Christopher J

2011-12-01

54

The effect of aquatic plant abundance on shell crushing resistance in a freshwater snail.  

PubMed

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

55

APPLICATION OF McKENDRICK - VON FOERSTER'S MODEL OF POPULATION DYNAMICS TO FRESHWATER SNAILS: SPECIFICATION OF THE MODEL USING LABORATORY EXPERIMENTS *)  

Microsoft Academic Search

The synthesis of the methods of field observation, of laboratory experiments and mathematical modelling was used when studying the life history of freshwater snail Bithynia tentaculata (Linné, 1758) (Prosobranchia) in the River Svratka (South Moravia, Czech Republic). McKendrick - von Foerster's model of population dynamics based on the analysis of seasonal changes in abundance and on the size structure of

Ivona Velecká; Libor Jüttner

56

WYNTK_pulmon.mobi  

Cancer.gov

Lo_que_usted-ncer_de_pulmonSjSjBOOKMOBI]8&-28? F MSY`fnu|?B 4"z$&(*,.02468 :@HBPD`F4HXJLvNRTVXZ\\^` bd`f#@h+j2l:nB;pJrSDt[7vaxhzo|v~~|!6*fr"V3.32kk " ^ MOBINb:7 HP#%$&R EXTHt kprj2014-04-30d&Instituto Nacional del Cncere&Instituto Nacional del Cncer Ciiw es horizontal-lrkindle:embed:0008 ,>

57

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

58

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

59

Life history traits variation in heterogeneous environment: The case of a freshwater snail resistance to pond drying  

PubMed Central

Ecologists and population geneticists have long suspected that the diversity of living organisms was connected to the structure of their environment. In heterogeneous environments, diversifying selection combined to restricted gene flow may indeed lead to locally adapted populations. The freshwater snail, Galba truncatula, is a good model to address this question because it is present in a heterogeneous environment composed of temporary and permanent waters. In order to test the selective importance of those environments, we proposed here to measure survival of lineages from both habitats during drought episodes. To this purpose, we experimentally submitted adults and juveniles individuals from both habitats to drought. We found a difference in desiccation resistance between temporary and permanents waters only for adults. Adults from temporary habitats were found more resistant to drought. This divergence in desiccation resistance seems to explain the unexpected life history traits differences between habitats observed. PMID:22408738

Chapuis, Elodie; Ferdy, Jean-Baptiste

2012-01-01

60

Freshwater snails and schistosomiasis mansoni in the state of Rio de Janeiro, Brazil: V -- Norte Fluminense Mesoregion.  

PubMed

In this paper, the fifth 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 Norte Fluminense Mesoregion from 2002 to 2003 are presented and revealed the occurrence of 19 species: Antillorbis nordestensis; Burnupia sp.; Biomphalaria tenagophila; Drepanotrema anatinum; Drepanotrema cimex; Drepanotrema depressissimum; Drepanotrema lucidum; Ferrissia sp.; Gundlachia ticaga; Gundlachia sp.; Heleobia sp.; Hebetancylus moricandi; Idiopyrgus sp.; Lymnaea columella; Melanoides tuberculatus; Physa acuta; Physa marmorata; Pomacea sordida, and Pomacea sp. Concerning the snail hosts of Schistosoma mansoni only B. tenagophila was found, in contrast with other previuosly studied mesoregions.No specimens were found harbouring larval forms of S. mansoni although different kinds of cercariae had been observed. An account about the current schistosomiasis transmission sites in this Mesoregion is presented as well. PMID:15486644

Thiengo, Silvana C; Mattos, Aline C; Boaventura, M Fernanda; Loureiro, Márcio S; Santos, Sonia B; Fernandez, Monica A

2004-01-01

61

Freshwater snails and schistosomiasis mansoni in the state of Rio de Janeiro, Brazil: VI--Noroeste Fluminense Mesoregion.  

PubMed

In this paper, the last 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 Noroeste Fluminense Mesoregion from 2002 to 2005 are presented and revealed the occurrence of 20 species: Antillorbis nordestensis; Biomphalaria glabrata; B. straminea; B. tenagophila; Drepanotrema anatinum; D. cimex; D. depressissimum; D. lucidum; Ferrissia sp.; Gundlachia ticaga; Gundlachia sp.; Heleobia sp.; Idiopyrgus sp.; Lymnaea columella; Melanoides tuberculatus; Physa acuta; P. marmorata; Plesiophysa guadeloupensis; Pomacea lineata; and Pomacea sp. Concerning the snail hosts of schistosomiasis the three natural vectors were identified and, although no specimens were found harbouring larval forms of Schistosoma mansoni, different kinds of cercariae had been observed. PMID:17308776

Thiengo, Silvana C; Mattos, Aline C; Santos, Sonia B; Fernandez, Monica A

2006-09-01

62

Freshwater snails and Schistosomiasis mansoni in the state of Rio de Janeiro, Brazil: IV - Sul Fluminense Mesoregion.  

PubMed

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; Drepanotrema lucidum; Ferrissia sp.; Gundlachia ticaga; Gundlachia sp.; Heleobia sp.; Lymnaea columella; Melanoides tuberculatus; Physa acuta; Physa marmorata; Pomacea sordida and Pomacea sp. As to the snail hosts of Schistosoma mansoni the most frequent species was B. tenagophila, found in all municipalities surveyed, except Parati. Besides new records the present study extends the distribution of B. peregrina and B. straminea in the state. No specimens were found harbouring larval forms of S. mansoni although different kinds of cercariae had been observed. An account about the current schistosomiasis transmission sites in this Mesoregion is presented as well. PMID:15273799

Thiengo, Silvana C; Mattos, Aline C; Boaventura, M Fernanda; Fernandez, Monica A

2004-05-01

63

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

64

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

65

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

66

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

USGS Publications Warehouse

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.

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

2014-01-01

67

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

68

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...

69

Identification of an estrogen receptor gene in the natural freshwater snail Bithynia tentaculata.  

PubMed

Mollusks have received increasing interest in ecotoxicological studies but so far the available scientific analyses of how their genes are affected by anthropogenic pollutants are scarce. The focus of this study is to identify an estrogen receptor (er) gene in the common prosobranch snail Bithynia tentaculata and to test a hypothesis that 17?-Ethinylestradiol (EE2) will modulate er gene expression after short-term exposure. We set up exposure experiments with a total of 144 snails, which were collected from a natural population in southern Sweden. Snails were exposed to either 10ng/L or 100ng/L EE2 during 24h and/or 72h. From the isolated B. tentaculata RNA we successfully identified and characterized a novel er gene and phylogenetic analyses strongly indicate that the Bithynia er gene is an ortholog to the human ER? (ESR1, NR3A1). We found a significant interaction between EE2-dose and exposure duration on the er's gene expression (Two-way ANOVA; p=0.04). We also found a significant difference in the gene expression of the er when comparing the control and 100ng/L treatment groups after 72h in female snails (One-way ANOVA; p=0.047). The results from this study should be useful for future field-related studies of estrogen receptors in natural populations of mollusks. PMID:24583164

Hultin, Cecilia L; Hallgren, Per; Persson, Anders; Hansson, Maria C

2014-04-25

70

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

71

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.

Ghesquiere, Stijn A.

72

Determination of digestive enzyme kinetics: a new method to define trophic niches in freshwater snails  

Microsoft Academic Search

Fluorogenic substrate analogues (MUF substrates) are very sensitive in detecting hydrolytic enzymes. This method was adapted\\u000a for the quantitative analysis of extracellular enzymes in snails and other animals. It was then used to determine cellobiase,\\u000a chitobiase, protease, esterase, phosphatase and lipase in the digestive tract of Radix \\u000a peregra and Bithynia \\u000a tentaculata. The method was sensitive enough to determine the complete

Heinz Brendelberger

1996-01-01

73

Peroxisomes in pulmonate gastropods.  

PubMed

Organelles with the morphologic characteristics of peroxisomes have been found in the cells of the kidney sac of two terrestrial pulmonate gastropods. Arion ater and Ariolimax columbianus. These peroxisomes appear in profile as circles or ellipses, 0.25 micron in diameter and 0.3-0.8 micron long; They have a finely granular matrix and a single-limiting membrane; the organelles are extensively associated with smooth endoplasmic reticulum. Some Ariolimax peroxisomes contained structures reminiscent of nucleoids while those of Arion did not. The peroxisomes of Arion ater show a strongly-positive staining reaction with the 3,3'-diaminobenzidine technique, which is inhibited in the presence of aminotriazole. Peroxisomes of Ariolimax columbianus did not show a positive reaction, despite a number of variations of the 3,3'-diaminobenzidine protocol. Speculations are made concerning the biochemical reasons for this cytochemical behavior. Peroxisomes in both tissues were negatively stained while lysosomes were positively stained in acid-phosphatase incubations. PMID:864236

Dannen, E; Beard, M E

1977-05-01

74

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

75

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

76

The ITS2 of the genus Bulinus: novel secondary structure among freshwater snails and potential new taxonomic markers.  

PubMed

The freshwater snail genus Bulinus has been intensively investigated due to its role as intermediate host for trematode blood flukes that cause the debilitating disease schistosomiasis in man and livestock. Owing to taxonomic ambiguities within Bulinus, attention has often focused upon species delineation and several molecular methods have recently been used for identification and characterization purposes. Inspection of compensatory base changes (CBCs) in the secondary structure of the nuclear ribosomal internal transcribed spacer (ITS) has been used to differentiate species in other genera, and here we present a study investigating the presence of CBCs between species in the species groups within Bulinus. CBCs were present within B. forskalii and B. globosus indicating that these widely distributed taxa might constitute cryptic species complexes. However, other currently recognized species could not be distinguished by CBC analysis. The putative secondary structure of the very long ITS2 sequence of the B. reticulatus species group had an additional helix (DIIa) between DII and DIII not seen in other species groups of Bulinus. The accumulation and inspection of further ITS2 sequences will no doubt reveal additional variation between Bulinus populations, and CBCs should be incorporated in future taxonomic work in this group. PMID:22677601

Jørgensen, Aslak; Stothard, J R; Madsen, Henry; Nalugwa, Allen; Nyakaana, Silvester; Rollinson, David

2013-11-01

77

[Freshwater snails of the Campus of Manguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, RJ].  

PubMed

A survey of freshwater gastropods of the Campus of Manguinhos, Fundação Oswaldo Cruz, Rio de Janeiro, was carried out during the last two years aiming to compare the current species with those found at the beginning of this century. Among 18 breeding sites in 880,000m2 of the surveyed area, 13 showed the following species: Antillorbis nordestensis; Biomphalaria glabrata; Biomphalaria straminea; Lymnaea columella; Melanoides tuberculatus; Physa cubensis; Pomacea glauca and Pomacea lineata. Notably, Biomphalaria tenagophila reported by Lutz in 1918, had disappeared and B. straminea and the Asiatic thiarid M. tuberculatus had been introduced. No specimens infected with Schistosoma mansoni were found. PMID:11460215

Fernandez, M A; Thiengo, S C; Boaventura, M F

2001-01-01

78

Spore ornamentation of Haplosporidium pickfordi Barrow, 1961 (Haplosporidia), a parasite of freshwater snails in Michigan, USA.  

PubMed

Spore ornamentation is increasingly recognized as a key character for species differentiation and genus assignment in the phylum Haplosporidia. Unfortunately, spore ornamentation is known for only a small number of described species so it is difficult to assign most species to genera with any confidence. Scanning and transmission electron microscopy were used to determine the presence and morphology of spore ornamentation of Haplosporidium pickfordi collected from the digestive gland of the snail Physella parkeri in Douglas Lake, Michigan. Spores possess filaments that are derived from the spore wall and originate from two separate areas at the posterior end of the spore. When spores are first isolated from host tissue, filaments are fused into a sheet that wraps around the spore, passing under the opercular lid. These filaments gradually unravel when spores are held in water and after about 14 d most filaments project freely from the posterior end of the spore. The number of filaments could not be determined with certainty, but appears to be approximately nine. Filaments are 100 nm in diam. and up to 50 microm in length. The presence of spore wall-derived filaments confirms the placement of the parasite in the genus Haplosporidium. PMID:11831770

Burreson, E M

2001-01-01

79

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

80

The effects of water availability on the life history of the desert snail, Trochoidea seetzeni  

Microsoft Academic Search

Summary In the Negev desert of Israel, the pulmonate land snailTrochoidea seetzeni is active, grows and reproduces in the month following the torrential winter rains. Thereafter, these snails estivate until the following year's rains. By experimental supplementation of water in the field, we examined the ability of these snails to alter their life histories. Specifically, we measured changes in feeding

David Ward; Robert Slotow

1992-01-01

81

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

82

Freshwater snails and schistosomiasis mansoni in the State of Rio de Janeiro, Brazil: I-- Metropolitan mesoregion.  

PubMed

In order to elaborate a planorbid chart of the State of Rio de Janeiro a survey of freshwater gastropods in the Metropolitan Mesoregion of this State was performed and revealed the occurrence of 20 species: Antillorbis nordestensis (Lucena, 1954); Biomphalaria glabrata (Say, 1818); Biomphalaria schrammi (Crosse, 1864); Biomphalaria straminea (Dunker, 1848); Biomphalaria tenagophila (Orbigny, 1835); Burnupia sp.; Drepanotrema anatinum (Orbigny, 1835); Drepanotrema cimex (Moricand, 1839); Drepanotrema lucidum (Pfeiffer, 1839); Ferrissia sp.; Gundlachia ticaga (Marcus & Marcus, 1962); Heleobia davisi Silva & Thomé, 1985; Lymnaea columella Say, 1817; Melanoides tuberculatus (Müller, 1774); Physa cubensis Pfeiffer, 1839; Physa marmorata Guilding, 1828; Pomacea sp.; Pomacea canaliculata (Lamarck, 1822); Pomacea lineata (Spix, 1827) and Pomacea sordida (Swainson, 1823). Among the planorbid species B. tenagophila was the most frequent, occurring in all municipalities surveyed. The present study extends the distribution of B. straminea in the State of Rio de Janeiro and reports new records for A. nordestensis, B. schrammi, G. ticaga, H. davisi and the genera Burnupia and Ferrissia. An account about the current transmission areas of schistosomiasis mansoni in this Mesoregion is presented as well. PMID:11586447

Thiengo, S C; Fernandez, M A; Boaventura, M F; Grault, C E; Silva, H F; Mattos, A C; Santos, S B

2001-01-01

83

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.

New Jersey

2006-01-01

84

Distribution of freshwater snails in the river Niger basin in Mali with special reference to the intermediate hosts of schistosomes  

Microsoft Academic Search

Snail surveys were carried out in various parts of Mali. All areas surveyed are part of the Niger basin being either affluents\\u000a or irrigation schemes fed by this river. The snail species present varied greatly between areas. The following potential hosts\\u000a of schistosomes were recorded: Biomphalaria pfeifferi, Bulinus truncatus, B. globosus, B. umbilicatus, B. forskalii and B. senegalensis.\\u000a \\u000a In the

Henry Madsen; Godefroy Coulibaly; Peter Furu

1987-01-01

85

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

86

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

87

Detection of Ehrlichia risticii, the Agent of Potomac Horse Fever, in Freshwater Stream Snails (Pleuroceridae: Juga spp.) from Northern California  

Microsoft Academic Search

Ehrlichia DNA was identified by nested PCR in operculate snails (Pleuroceridae: Juga spp.) collected from stream water in a northern California pasture in which Potomac horse fever (PHF) is enzootic. Sequencing of PCR-amplified DNA from a suite of genes (the 16S rRNA, groESL heat shock operon, 51-kDa major antigen genes) indicated that the source organism closely resembled Ehrlichia risticii, the

JEFFREY E. BARLOUGH; GERHARD H. REUBEL; JOHN E. MADIGAN; LARISA K. VREDEVOE; PAUL E. MILLER; YASUKO RIKIHISA

1998-01-01

88

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

89

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

90

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

PubMed Central

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

Hanif, Farhat; Singh, Dinesh Kumar

2013-01-01

91

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

92

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

93

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

94

Effects of selection and drift on G matrix evolution in a heterogeneous environment: a multivariate Qst-Fst Test with the freshwater snail Galba truncatula.  

PubMed

Unraveling the effect of selection vs. drift on the evolution of quantitative traits is commonly achieved by one of two methods. Either one contrasts population differentiation estimates for genetic markers and quantitative traits (the Q(st)-F(st) contrast) or multivariate methods are used to study the covariance between sets of traits. In particular, many studies have focused on the genetic variance-covariance matrix (the G matrix). However, both drift and selection can cause changes in G. To understand their joint effects, we recently combined the two methods into a single test (accompanying article by Martin et al.), which we apply here to a network of 16 natural populations of the freshwater snail Galba truncatula. Using this new neutrality test, extended to hierarchical population structures, we studied the multivariate equivalent of the Q(st)-F(st) contrast for several life-history traits of G. truncatula. We found strong evidence of selection acting on multivariate phenotypes. Selection was homogeneous among populations within each habitat and heterogeneous between habitats. We found that the G matrices were relatively stable within each habitat, with proportionality between the among-populations (D) and the within-populations (G) covariance matrices. The effect of habitat heterogeneity is to break this proportionality because of selection for habitat-dependent optima. Individual-based simulations mimicking our empirical system confirmed that these patterns are expected under the selective regime inferred. We show that homogenizing selection can mimic some effect of drift on the G matrix (G and D almost proportional), but that incorporating information from molecular markers (multivariate Q(st)-F(st)) allows disentangling the two effects. PMID:18854589

Chapuis, Elodie; Martin, Guillaume; Goudet, Jérôme

2008-12-01

95

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

Microsoft Academic Search

This study aims to demonstrate the influence of the metabolic CO2 derived from the diet and of the atmospheric CO2 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

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

2003-01-01

96

Land and water snails  

NSDL National Science Digital Library

Land snails live on the land and water snails make water their habitat. Land snails have shells to protect them and so do water snails. Land snails have two sets of antennae, while water snails only have one set.

Olivia Worland (Purdue University; Biological Sciences)

2008-06-03

97

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

98

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

99

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

100

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

101

Garden snail  

NSDL National Science Digital Library

One reason why the snail is considered to be a mollusk is because it doesn't have any legs. It moves around on its belly, which is actually called the foot. Some snails live in water while others only live on land.

Danielle N/A (None;)

2007-07-28

102

Snail Trails  

ERIC Educational Resources Information Center

The slime trails of snails lead the author's students to a better understanding of science as inquiry and the processes of science. During this five-day activity, students get up close and personal with one of her favorite creatures, the land snail. Students begin by observing the organism and recording their observations. After making initial…

Galus, Pamela

2002-01-01

103

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

104

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....

105

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

106

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

107

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

108

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

109

Occurrence of larval Philophthalmus gralli (Mathis and Leger, 1910) in freshwater snail Melanoides tuberculatus (Muller) from Al-Hafuf, Saudi Arabia and its development into adult in various experimental hosts  

Microsoft Academic Search

This is the first report of occurrence of Philophthalmus gralli in Melanoides tuberculatus from Saudi Arabia. The overall infection rate of M. tuberculatus with P. gralli larvae was 8.9%. However, the incidence of infection varied from 6.46 to 10.16% depending on the size of the snail, and larger snails were found to be more infected than the smaller ones. The

A. M. N. Kalantan; M. Arfin; H. A. Al-Arefi; H. I. Bobshait; S. A. Hamadah; F. H. Al-Thawab; A. A. Al-Shamrani

1997-01-01

110

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

111

The convoluted evolution of snail chirality  

NASA Astrophysics Data System (ADS)

The direction that a snail (Mollusca: Gastropoda) coils, whether dextral (right-handed) or sinistral (left-handed), originates in early development but is most easily observed in the shell form of the adult. Here, we review recent progress in understanding snail chirality from genetic, developmental and ecological perspectives. In the few species that have been characterized, chirality is determined by a single genetic locus with delayed inheritance, which means that the genotype is expressed in the mother's offspring. Although research lags behind the studies of asymmetry in the mouse and nematode, attempts to isolate the loci involved in snail chirality have begun, with the final aim of understanding how the axis of left-right asymmetry is established. In nature, most snail taxa (>90%) are dextral, but sinistrality is known from mutant individuals, populations within dextral species, entirely sinistral species, genera and even families. Ordinarily, it is expected that strong frequency-dependent selection should act against the establishment of new chiral types because the chiral minority have difficulty finding a suitable mating partner (their genitalia are on the ‘wrong’ side). Mixed populations should therefore not persist. Intriguingly, however, a very few land snail species, notably the subgenus Amphidromus sensu stricto, not only appear to mate randomly between different chiral types, but also have a stable, within-population chiral dimorphism, which suggests the involvement of a balancing factor. At the other end of the spectrum, in many species, different chiral types are unable to mate and so could be reproductively isolated from one another. However, while empirical data, models and simulations have indicated that chiral reversal must sometimes occur, it is rarely likely to lead to so-called ‘single-gene’ speciation. Nevertheless, chiral reversal could still be a contributing factor to speciation (or to divergence after speciation) when reproductive character displacement is involved. Understanding the establishment of chirality, the preponderance of dextral species and the rare instances of stable dimorphism is an important target for future research. Since the genetics of chirality have been studied in only a few pulmonate species, we also urge that more taxa, especially those from the sea, should be investigated.

Schilthuizen, M.; Davison, A.

2005-11-01

112

Microscopy and Morphometry of Integument of the Foot of Pulmonate Gastropods Arion rufus and Helix pomatia  

Microsoft Academic Search

Tonar Z., A. Marko‰: Microscopy and Morphometry of Integument of the Foot of Pulmonate Gastropods Arion rufus and Helix pomatia. Acta Vet. Brno 2004, 73: 3-8. The aim of our work was to carry out morphometric analysis of histological sections through the foot of pulmonate gastropods with an output suitable as a data entry for its biomechanical scale- dependent modelling.

Z. TONAR; A. MARKO

113

Combined percutaneous treatment of atrial septal defect and pulmonic or aortic stenosis in adult patients  

PubMed Central

Combined atrial septal defect and pulmonic or aortic stenosis are relatively uncommon conditions in adult patients, with few reported cases of percutaneous treatment. We present two patients with secundum type atrial septal defect and concomitant pulmonic or aortic stenosis and their treatment by transcatheter techniques. PMID:22427776

Linhartova, Katerina; Antonova, Petra; Adlova, Radka; Alan, David; Veselka, Josef

2010-01-01

114

Nucleolar organizer regions in Biomphalaria and Bulinus snails  

Microsoft Academic Search

Summary A method is described for the demonstration of nucleolar organizer regions (NORs) in freshwater snails and is applied to the study of one tetraploid and several diploid populations ofBulinus. We present evidence of dosage compensation with respect to the expression of NORs in that diploids and tetraploids both exhibit only 1 pair of NOR-bearing chromosomes.

M. A. Goldman; P. T. LoVerde; C. L. Chrisman; D. A. Franklin; F. Matthews; R. J. Pitchford; C. S. Richards

1983-01-01

115

Growth and cell viability of aortic versus pulmonic homografts in the systemic circulation.  

PubMed

Growth characteristics and cell viability of aortic and pulmonic valve homografts in the systemic circulation were compared in a growing sheep model. Seven aortic and seven pulmonic cryopreserved homografts were implanted in the descending aortae of recipient female lambs. Of seven sheep per group, three were killed at 8 months, three at 12 months, and one at 15 months. Tissue cultures were obtained on homograft valve and root wall specimens. Male donor cells were identified by chromosome analysis. Preimplant to explant changes in pulmonic homograft external diameters at the valve annulus and sinotubular junction increased significantly more than in aortic roots. The postoperative dimensions of the distal anastomotic diameter and length of the graft increased significantly more in pulmonic than in aortic roots by time of explant. Leaflet calcification and valvular stenosis did not develop in either pulmonic or aortic homografts over the period of observation. Calcification in the root wall was significantly less in pulmonic than aortic homografts. Growth on tissue culture was obtained from over 70% of homograft specimens. Viable donor cells were demonstrated in none and 43% of aortic and pulmonic leaflets, respectively, and 71% and 57% of aortic and pulmonary arterial homograft walls, respectively. In conclusion, both aortic and pulmonic homograft valves provide freedom from calcification and stenosis in this model. Continuing expansion of pulmonic root diameters under systemic pressure might lead to late aneurysm formation. Although host cell repopulation of grafts may be advantageous, the presence of viable donor cells in leaflet tissue does not seem necessary to prevent calcific degeneration. PMID:1934449

Allen, M D; Shoji, Y; Fujimura, Y; Gordon, D; Thomas, R; Brockbank, K G; Disteche, C M

1991-11-01

116

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

117

Lemierre's Syndrome: A Rare Case of Pulmonic Valve Vegetation.  

PubMed

Lemierre's syndrome is an uncommon complication of pharyngitis commonly associated with an anaerobic gram negative bacterium, Fusobacterium necrophorum. The syndrome usually affects young healthy adults with the mean age of 20 and is characterized by recent pharyngitis followed by ipsilateral internal jugular vein thrombosis and septic thromboembolism. The treatment is at least 6 weeks of antibiotics; the role of anticoagulation is unclear. The following presentation is a case of Lemierre's syndrome in a 23-year-old healthy individual who is infected by a rare species: Fusobacterium nucleatum. The case is complicated by septic emboli to the lungs and impressive seeding vegetation to the right ventricular outflow tract (RVOT) at the pulmonic valve of the heart. PMID:23573433

Kwan, Clara; Mastrine, Lou; Moskovits, Manfred

2013-01-01

118

Lemierre's Syndrome: A Rare Case of Pulmonic Valve Vegetation  

PubMed Central

Lemierre's syndrome is an uncommon complication of pharyngitis commonly associated with an anaerobic gram negative bacterium, Fusobacterium necrophorum. The syndrome usually affects young healthy adults with the mean age of 20 and is characterized by recent pharyngitis followed by ipsilateral internal jugular vein thrombosis and septic thromboembolism. The treatment is at least 6 weeks of antibiotics; the role of anticoagulation is unclear. The following presentation is a case of Lemierre's syndrome in a 23-year-old healthy individual who is infected by a rare species: Fusobacterium nucleatum. The case is complicated by septic emboli to the lungs and impressive seeding vegetation to the right ventricular outflow tract (RVOT) at the pulmonic valve of the heart. PMID:23573433

Kwan, Clara; Mastrine, Lou; Moskovits, Manfred

2013-01-01

119

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

120

All About Snails  

NSDL National Science Digital Library

This website introduces younger students to snails. Topics include their physical characteristics and living habits, diet, reproduction, locomotion, life history, predators, and many others. There are also links to additional material on snails, including lesson plans, stories, poems, and songs, clip-art, art and craft activties, and other resources.

2001-11-01

121

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

122

The Classroom Animal: Snails.  

ERIC Educational Resources Information Center

Points out that snails are interesting and easily-managed classroom animals. One advantage of this animal is that it requires no special attention over weekends or holidays. Background information, anatomy, reproduction, and feeding are discussed, along with suggestions for housing aquatic and/or land snails. (DH)

Kramer, David S.

1985-01-01

123

An ecological study of Bithynia snails, the first intermediate host of Opisthorchis viverrini in northeast Thailand.  

PubMed

Infection with the food-borne trematodiasis, liver fluke Opisthorchis viverrini, is a major public health concern in Southeast Asia. While epidemiology and parasitic incidence in humans are well studied, ecological information on the O. viverrini intermediate hosts remains limited. This study aimed to investigate the factors affecting the distribution and abundance of the first intermediate host, Bithynia siamensis goniomphalos snails. Water quality and snails were sampled in 31 sites in Muang District, Khon Kaen Province, Thailand from June 2012 to January 2013 to characterize the B.s. goniomphalos snail habitats. Species relative abundance and Shannon's diversity and evenness indices were employed to describe snail compositions and diversities across different habitat types. Statistical analyses were conducted to examine the extent to which the water quality variables and species interactions account for the relative abundance of B.s. goniomphalos snails. The results showed that the freshwater habitats of ponds, streams and rice paddies possessed significantly different abiotic water qualities, with water temperature and pH showing distinct statistical differences (P<0.05). Different habitats had different snail diversity and species evenness, with high B.s. goniomphalos snail abundance at rice paddy habitats. The differences in snail abundance might be due to the distinct sets of abiotic water qualities associated with each habitat types. The relative abundance of B.s. goniomphalos snails was found to be negatively correlated with that of Filopaludina martensi martensi snails (r=-0.46, P<0.05), underscoring the possible influence of species interaction on B.s. goniomphalos snail population. Field work observations revealed that rice planting seasons and irrigation could regulate snail population dynamics at rice paddy habitats. This study provides new ecological insights into the factors affecting Bithynia snail distribution and abundance. It bridges the knowledge gap in O. viverrini disease ecology and highlights the potential effect of anthropogenic irrigation practices on B.s. goniomphalos snail ecology. PMID:24561073

Wang, Yi-Chen; Ho, Richard Cheng Yong; Feng, Chen-Chieh; Namsanor, Jutamas; Sithithaworn, Paiboon

2015-01-01

124

Combined tricuspid and pulmonic stenosis. Clinical, echocardiographic, hemodynamic, surgical, and pathological features.  

PubMed

A 30-year-old man with a history of a murmur since childhood had progressive ascites for 2 years. The patient was found to have severe stenoses of the pulmonic and tricuspid valves with a well-developed right ventricle. Impressive clinical improvement occurred after pulmonic valvotomy, infundibulectomy, and replacement of the stenotic tricuspid valve with a porcine xenograft. The clinical, echocardiographic, hemodynamic, surgical, and pathological features are presented. PMID:559886

Mehl, S J; Kaltman, A J; Kronzon, I; Dworkin, L; Adams, P; Spencer, F C

1977-07-01

125

Periphyton removal by freshwater micrograzers  

Microsoft Academic Search

\\u000a In various experiments, the freshwater snail species Lymnaea peregra (Müll.), Physa fontinalis (L.), Valvata piscinalis (Müll.) and Bithynia tentaculata (L.) significantly removed periphyton from glass slides, while the two tested crustacean species, Asellus aquaticus (L.) and Gammarus pulex (L.), did not. B. tentaculata removed similar amounts of periphyton accumulated in the field as it did of laboratory-cultured periphyton.\\u000a \\u000a \\u000a Removal rates

J. E. Vermaat

1993-01-01

126

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

127

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

128

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)

129

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

130

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.

Chicago Children's Museum

2011-01-01

131

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

132

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

133

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

134

Inquiry, Land Snails, and Environmental Factors.  

ERIC Educational Resources Information Center

Introduces land snails for use in inquiry-based science activities. Describes common characteristics and safety considerations while introducing students to land snails. Explains procedures for inquiry-based use of land snails in classrooms. (YDS)

Barrow, Lloyd H.; Krantz, Patrick D.

2002-01-01

135

Demographic Responses to Multigeneration Cadmium Exposure in Two Strains of the Freshwater Gastropod, Biomphalaria  

E-print Network

Demographic Responses to Multigeneration Cadmium Exposure in Two Strains of the Freshwater cadmium exposure on two strains of the freshwater gastropod, Biomphalaria glabrata: the parasite- resistant BS90 and parasite-susceptible NMRI strains. Snails were exposed to waterborne cadmium for three

Miller, Tom

136

O-Glycosylation of snails.  

PubMed

The glycosylation abilities of snails deserve attention, because snail species serve as intermediate hosts in the developmental cycles of some human and cattle parasites. In analogy to many other host-pathogen relations, the glycosylation of snail proteins may likewise contribute to these host-parasite interactions. Here we present an overview on the O-glycan structures of 8 different snails (land and water snails, with or without shell): Arion lusitanicus, Achatina fulica, Biomphalaria glabrata, Cepaea hortensis, Clea helena, Helix pomatia, Limax maximus and Planorbarius corneus. The O-glycans were released from the purified snail proteins by ?-elimination. Further analysis was carried out by liquid chromatography coupled to electrospray ionization mass spectrometry and - for the main structures - by gas chromatography/mass spectrometry. Snail O-glycans are built from the four monosaccharide constituents: N-acetylgalactosamine, galactose, mannose and fucose. An additional modification is a methylation of the hexoses. The common trisaccharide core structure was determined in Arion lusitanicus to be N-acetylgalactosamine linked to the protein elongated by two 4-O-methylated galactose residues. Further elongations by methylated and unmethylated galactose and mannose residues and/or fucose are present. The typical snail O-glycan structures are different to those so far described. Similar to snail N-glycan structures they display methylated hexose residues. PMID:22581130

Stepan, Herwig; Pabst, Martin; Altmann, Friedrich; Geyer, Hildegard; Geyer, Rudolf; Staudacher, Erika

2012-05-01

137

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

138

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

139

Polymorphism in pleistocene land snails.  

PubMed

Under suitable conditions the colors and patterns of the shells of land snails may be preserved for thousands of years. In a late Pleistocene population of Limicolaria martensiana all the major color forms that occur in modern living snails may be distinguished, and the basic polymorphism is at least 8,000 to 10,000 year old. PMID:17830234

Owen, D F

1966-04-01

140

Glow-Worms nu Snails  

Microsoft Academic Search

YOUR correspondent, Mr. R. S. Newall, has unconsciously reversed the natural condition of affairs in his note (NATURE, vol. xx. p. 197). The heading should have been as above Glow-worms devour snails, which are their natural food. The particular snail in question had probably been attacked by the one of the glow-worms, which had left some of its phosphorescent matter

R. McLachlan

1879-01-01

141

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.

Sciences, Bigelow L.

142

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...

143

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

144

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

145

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

146

Major carbon-14 deficiency in modern snail shells from southern Nevada springs  

USGS Publications Warehouse

Carbon-14 contents as low as 3.3 ?? 0.2 percent modern (apparent age, 27,000 years) measured from the shells of snails Melanoides tuberculatus living in artesian springs in southern Nevada are attributed to fixation of dissolved HCO3- with which the shells are in carbon isotope equilibrium. Recognition of the existence of such extreme deficiencies is necessary so that erroneous ages are not attributed to freshwater biogenic carbonates.

Riggs, A.C.

1984-01-01

147

Major carbon-14 deficiency in modern snail shells from southern nevada springs.  

PubMed

Carbon-14 contents as low as 3.3 +/- 0.2 percent modern (apparent age, 27,000 years) measured from the shells of snails Melanoides tuberculatus living in artesian springs in southern Nevada are attributed to fixation of dissolved HCO(3)(-) with which the shells are in carbon isotope equilibrium. Recognition of the existence of such extreme deficiencies is necessary so that erroneous ages are not attributed to freshwater biogenic carbonates. PMID:17783523

Riggs, A C

1984-04-01

148

Behavioural evidence for a sleep-like quiescent state in a pulmonate mollusc, Lymnaea stagnalis (Linnaeus).  

PubMed

The objective of this study was to determine whether the great pond snail, Lymnaea stagnalis, expresses a sleep-like behavioural state. We found that snails spontaneously enter a relatively brief (22±1 min) quiescent state characterized by postural relaxation of the foot, mantle and tentacles, and cessation of radula rasping. Quiescence was reversed ('aroused') by appetitive (sucrose solution) and aversive (tactile) stimuli. Responsiveness to both stimuli was significantly lower in quiescent snails than in active snails. However, tactile stimuli evoked a more sustained defensive response in quiescent snails. Quiescence bouts were consolidated into 'clusters' over an infradian timescale and were only weakly affected by time of day. Clusters contained 7±0.5 bouts, lasted 13±1 h and were separated by long (37±4 h) intervals of almost continuous activity. Analysis of Kaplan-Meier survival curves revealed that the quiescent bout duration was described by an exponential probability distribution (time constant 15±1 min). Active bout duration was described by a bi-exponential probability distribution (time constants 62±4 and 592±48 min). We found no evidence for a 'sleep rebound' mechanism and quiescence expression appeared to be regulated through stochastic processes causing state transitions to resemble a Markovian random walk. We conclude that Lymnaea is a potentially valuable model system for studies of cellular function in sleep. PMID:21307060

Stephenson, Richard; Lewis, Vern

2011-03-01

149

A study on snail location by Fasciola hepatica using radioisotopically labelled miracidia.  

PubMed

A number of common freshwater molluscs were exposed to Fasciola hepatica miracidia labelled in vivo with radioselenium. Radioactivity was rapidly incorporated in all lymnaeid species tested (L. stagnalis, L. tomentosa and L. truncatula) whereas no radioactivity could be demonstrated in non-lymnaeid pulmonate species (Aplexa hypnorum, Physa acuta, Physa fontinalis, Anisus vortex, Gyraulus albus and Planorbis planorbis) or in the prosobranchs Valvata cristata and Valvata piscinalis. However, the prosobranchs Bithynia leachii, Bithynia tentaculata and Potamopyrgus jenkinsi showed a slow but significant uptake of radioactivity which was presumably explained by uptake of labelled miracidia through a 'filter-feeding' mechanism. Sphaerium corneum, a true filter-feeder, showed a similar course of uptake of radioactivity. PMID:1264488

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

1976-04-01

150

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...

151

Assessment of whole effluent toxicity on aquatic snails: bioaccumulation of Cr, Zn, and Fe, and individual effects in bioassays.  

PubMed

We used a freshwater gastropod, Lymnaea palustris, in chronic bioassays to assess the toxicity of an industrial effluent containing high levels of metals, particularly Cr, Zn, and Fe. Adult snails were exposed for four weeks to different concentrations of effluent sampled at three successive treatment steps (crude effluent, effluent after physicochemical treatment, and after biological treatment). Dose-dependent responses reflecting exposure (metal bioaccumulation) and effects on survival, fecundity, and malondialdehyde production (a proxy for oxidative stress) were investigated. We found that Cr and Zn were accumulated in snail tissues, whereas Fe was regulated. Body concentrations of Cr and Zn decreased along the effluent-treatment gradient, particularly after the physicochemical treatment. For controls versus treatments, no effect on malondialdehyde production was detected. Significant effects were noted for fecundity. The number of eggs per individual decreased for snails exposed to 20, 30, and 40% concentrations of physicochemically treated effluent and for snails exposed to an 80% concentration of the biologically treated effluent. A hormetic effect on the number of eggs per individual was observed for snails exposed to 10 and 20% concentrations of the effluent that had been biologically treated. Deleterious effects of the effluent on L. palustris fecundity were not correlated with high internal concentrations of metals in the snails, suggesting that toxicity resulted from other factors. PMID:15683184

Coeurdassier, Michaël; de Vaufleury, Annette; Crini, Nadia; Scheifler, Renaud; Badot, Pierre-Marie

2005-01-01

152

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

SciTech Connect

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

Baturo, W.; Lagadic, L.; Caquet, T. [Univ. de Paris-Sud, Orsay (France). Lab. d`Ecologie et de Zoologie

1995-03-01

153

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

154

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 ...

155

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

156

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

PubMed

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

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

1982-03-01

157

Toxic Effects of Fluoride Ion on Survival, Reproduction and Behaviour of the Aquatic Snail Potamopyrgus antipodarum (Hydrobiidae, Mollusca)  

Microsoft Academic Search

Inorganic fluoride concentrations in aquatic ecosystems have been significantly increased by several human activities during\\u000a the last decades. However, there is still relatively scarce information about its toxicity to freshwater animals, especially\\u000a at long-term exposures. The aim of our study is to assess the short-term (4 days) and long-term (28 days) fluoride (F?) toxicity to the aquatic snail Potamopyrgus antipodarum on the

Álvaro Alonso; Julio A. Camargo

2011-01-01

158

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...

159

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

160

Latitudinal variation of freeze tolerance in intertidal marine snails of the genus Melampus (gastropoda: ellobiidae).  

PubMed

Abstract Low temperatures limit the poleward distribution of many species such that the expansion of geographic range can only be accomplished via evolutionary innovation. We have tested for physiological differences among closely related species to determine whether their poleward latitudinal ranges are limited by tolerance to cold. We measured lower temperature tolerance (LT50) among a group of intertidal pulmonate snails from six congeneric species and nine locales. Differences in tolerance are placed in the context of a molecular phylogeny based on one mitochondrial (cytochrome oxidase subunit I) and two nuclear (histone 3 and a mitochondrial phosphate carrier protein) markers. Temperate species from two separate lineages had significantly lower measures of LT50 than related tropical species. Range differences within the temperate zone, however, were not explained by LT50. These results show that multiple adaptations to cold and freezing may have enabled range expansions out of the tropics in Melampus. However, northern range limits within temperate species are not governed by cold tolerance alone. PMID:24940916

Dennis, A B; Loomis, S H; Hellberg, M E

2014-01-01

161

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

162

Snail bioaccumulation of triclocarban, triclosan, and methyltriclosan in a North Texas, USA, stream affected by wastewater treatment plant runoff.  

PubMed

Grazing by freshwater snails promotes nutrient turnover in algal communities. Grazed algal compartments may include antimicrobial agents and metabolites, such as triclocarban (TCC), triclosan (TCS), and methyltriclosan (MTCS), which are incompletely removed by wastewater treatment plant (WWTP) processing. The present study quantifies snail bioaccumulation factors (BAFs) for TCC, TCS, and MTCS at the outfall of Pecan Creek (TX, USA), the receiving stream for the city of Denton (TX, USA) WWTP. Helisoma trivolvis (Say) is ubiquitous and thrives under standard laboratory conditions, leading to its choice for this bioaccumulation study in conjunction with Cladophora spp. Along with providing substrate for epiphytic growth, Cladophora spp. provide a source of food and shelter for H. trivolvis. After being caged for two weeks, algae and snails were collected from the WWTP outfall, along with water-column samples, and analyzed by isotope dilution gas chromatography-mass spectrometry for TCS and MTCS and by liquid chromatography-mass spectrometry for TCC. Algal and snail samples were analyzed before exposure and found to be below practical quantitation limits for all antimicrobial agents. Triclocarban, TCS, and MTCS in water samples were at low-ppt concentrations (40-200 ng/L). Triclocarban, TCS, and MTCS were elevated to low-ppb concentrations (50-300 ng/g fresh wt) in caged snail samples and elevated to low-ppb concentrations (50-400 ng/g fresh wt) in caged algal samples. Resulting snail and algal BAFs were approximately three orders of magnitude, which supports rapid bioaccumulation among algae and adult caged snails at this receiving stream outfall. The results further support TCC, TCS, and MTCS as good candidate marker compounds for evaluation of environmental distribution of trace WWTP contaminants. PMID:18380516

Coogan, Melinda A; La Point, Thomas W

2008-08-01

163

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

164

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

165

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

PubMed

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 of antioxidant enzymes, such as superoxide dismutase and catalase, increased in 30 day-estivating snails. This appears to be an adaptation that allows the snails to deal with oxidative stress that takes place during arousal when PO2 and oxygen consumption rise rapidly. Indeed, oxidative stress was indicated by increased levels of lipid peroxidation damage products accumulating in hepatopancreas within minutes after arousal was initiated. The various metabolic sites responsible for free radical generation during arousal are still unknown but it seems unlikely that the enzyme xanthine oxidase plays any substantial role in this despite being implicated in oxidative stress in mammalian models of ischemia/reperfusion. We propose that the activation of antioxidant defenses in the organs of Otala lactea during estivation is a preparative mechanism against oxidative stress during arousal. Increased activities of antioxidant enzymes have also observed under other stress situations in which the actual production of oxyradicals should decrease. For example, antioxidant defenses are enhanced during anoxia exposure in garter snakes Thamnophis sirtalis parietalis (10 h at 5 degrees C) and leopard frogs Rana pipiens (30 h at 5 degrees C) and during freezing exposure (an ischemic condition due to plasma freezing) in T. sirtalis parietalis and wood frogs Rana sylvatica. It seems that enhancement of antioxidant enzymes during either anoxia or freezing is used as a preparatory mechanism to deal with a physiological oxidative stress that occurs rapidly within the early minutes of recovery during reoxygenation or thawing. Thus, a wide range of stress tolerant animals display coordinated changes in antioxidant defenses that allow them to deal with oxidative stress that occurs as part of natural cycles of stress/recovery that alter oxygen levels in tissues. The molecular mechanisms that trigger and regulate changes in antioxidant enzyme activities in these species are still unknown but could prove to have key relevance for the development of new intervention strategies in the treatment of cardiovascular ischemia/reperfusion injuries in humans. PMID:9787804

Hermes-Lima, M; Storey, J M; Storey, K B

1998-07-01

166

lnvertebratc Biology 121(3): 226-234. 0 2002 American Microscopical Society, Inc.  

E-print Network

of the European freshwater pulmonate Physa acuta are not reproductively isolated from American Physa heterostropha of reproductive success between species and between popula- tions within species. Samples of P. acuta were of snails from 2 continents. All should be referred to the oldest available nomen, P. acuta. Additional key

Dillon, Robert T.

167

No-choice mating experiments among six nominal taxa of the subgenus Physella (Basommatophora: Physidae)  

Microsoft Academic Search

Breeding studies have recently demonstrated no postzygotic reproductive isolation among several of the most common nomi- nal species in the subgenus Costatella of the widespread freshwater pulmonate snail family Physidae. Here we extend these results to include six nominal taxa in the other major subgenus of North American physids, Physella. We established first generation lines from the type or near-type

ROBERT T. DILLON; AMY R. WETHINGTON

168

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

169

Tentacular function in snail olfactory orientation  

Microsoft Academic Search

1.The olfactory orienting behavior of the terrestrial snailAchatina fulica was studied in intact animals, in animals with bilateral lesions of either the anterior tentacles or the posterior tentacles, and in animals with unilateral lesions of the posterior tentacles. Tentacular function was evaluated under three different conditions.2.One assay required the snails to locomote upwind in a two-armed olfactometer and enter the

Ronald Chase; Roger P. Croll

1981-01-01

170

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

171

Snail1, Snail2, and E47 promote mammary epithelial branching morphogenesis  

PubMed Central

Several E-box-binding transcription factors regulate individual and collective cell migration and enhance the motility of epithelial cells by promoting epithelial-mesenchymal transition (EMT). Here, we characterized the role of a subset of these transcription factors and the EMT proteome in branching morphogenesis of mammary epithelial tissues using a three-dimensional organotypic culture model of the mammary duct. We found that the transcription factors Snail1, Snail2, and E47 were transiently upregulated at branch sites; decreasing the expression of these transcription factors inhibited branching. Conversely, ectopic expression of Snail1, Snail2, and E47 induced branching in the absence of exogenous stimuli. These changes correlated with the expression of mesenchymal markers and repression of E-cadherin, which was essential for branching. Snail1 and Snail2 also promoted cell survival at branch sites, but this was not sufficient to induce branching. These findings indicate that Snail1, Snail2, and E47 can promote collective migration during branching morphogenesis of mammary epithelial tissues through key regulators of EMT. PMID:21610693

Lee, KangAe; Gjorevski, Nikolce; Boghaert, Eline; Radisky, Derek C; Nelson, Celeste M

2011-01-01

172

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

173

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

174

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

175

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

176

Bioaccumulation and effects of different-shaped copper oxide nanoparticles in the deposit-feeding snail Potamopyrgus antipodarum.  

PubMed

Copper oxide (CuO) nanoparticles (NPs) are among the most widely used engineered NPs and are thus likely to end up in the environment, predominantly in sediments. Copper oxide NPs have been found to be toxic to a variety of (mainly pelagic) organisms, but to differing degrees. In the present study, the influence of CuO NP shape on bioavailability and toxicity in the sediment-dwelling freshwater gastropod Potamopyrgus antipodarum was examined. In 2 separate studies, snails were exposed to either clean sediment or sediment spiked with either aqueous Cu or CuO NPs of different shapes (rods, spheres, or platelets) at 240?µg Cu/g dry weight of sediment (nominal). In neither of the studies was survival found to be related to Cu form (i.e., free ion vs particle) or shape, whereas snail growth was severely influenced by both form and shape. Reproduction was affected (by CuO NP spheres and aqueous Cu) only when estimated as the total number (live plus dead) of juveniles produced per snail per week. Both the aqueous and particulate forms of Cu were available for uptake by snails when mixed into sediment. However, Cu body burden was not directly related to observed effects. The present study stresses the need for both a better understanding of uptake mechanisms and internal distribution pathways of NPs and an assessment of long-term consequences of NP exposure. PMID:24862446

Ramskov, Tina; Selck, Henriette; Banta, Gary; Misra, Superb K; Berhanu, Deborah; Valsami-Jones, Eugenia; Forbes, Valery E

2014-09-01

177

Life-history traits indicate local adaptation of the schistosome parasite, Schistosoma mansoni, to its snail host, Biomphalaria pfeifferi.  

PubMed

The digenean trematode Schistosoma mansoni causes schistosomiasis (Bilharziasis), a significant human disease especially in sub-Saharan Africa. We tested local adaptation of this parasite to its intermediate host, the freshwater snail Biomphalaria pfeifferi, by exposure of S. mansoni to B. pfeifferi from one sympatric and four allopatric populations and measurement of life-history traits of both species over time. The pre-patent period, infection rate, and cercarial production of the parasite were determined, and the shell diameter, fecundity, and survival of the snail host were determined. The results provide evidence for local adaptation of S. mansoni to its sympatric snail host: the pre-patent period was the shortest, the cercarial production was moderate and accompanied by a higher survival rate, the growth was greater during the pre-patent period, and the fecundity was greater during the pre-patent period. The greater growth and fecundity of sympatric B. pfeifferi suggests the presence of growth and fecundity compensation. These fitness traits are relevant to energy allocation of the snail host and to the transmission strategy of the schistosome parasite. PMID:23031799

Ibikounlé, M; Mouahid, G; Mintsa Nguéma, R; Sakiti, N G; Kindé-Gasard, D; Massougbodji, A; Moné, H

2012-12-01

178

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

179

Snail1 Expression Is Required for Sarcomagenesis12  

PubMed Central

Snail1 transcriptional repressor is a major inducer of epithelial-to mesenchymal transition but is very limitedly expressed in adult animals. We have previously demonstrated that Snail1 is required for the maintenance of mesenchymal stem cells (MSCs), preventing their premature differentiation. Now, we show that Snail1 controls the tumorigenic properties of mesenchymal cells. Increased Snail1 expression provides tumorigenic capabilities to fibroblastic cells; on the contrary, Snail1 depletion decreases tumor growth. Genetic depletion of Snail1 in MSCs that are deficient in p53 tumor suppressor downregulates MSC markers and prevents the capability of these cells to originate sarcomas in immunodeficient SCID mice. Notably, an analysis of human sarcomas shows that, contrarily to epithelial tumors, these neoplasms display high Snail1 expression. This is particularly clear for undifferentiated tumors, which are associated with poor outcome. Together, our results indicate a role for Snail1 in the generation of sarcomas. PMID:24947186

Alba-Castellón, Lorena; Batlle, Raquel; Francí, Clara; Fernández-Aceñero, María J.; Mazzolini, Rocco; Peña, Raúl; Loubat, Jordina; Alameda, Francesc; Rodríguez, Rufo; Curto, Josué; Albanell, Joan; Muñoz, Alberto; Bonilla, Félix; Ignacio Casal, J.; Rojo, Federico; García de Herreros, Antonio

2014-01-01

180

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

181

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

182

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

183

Biodiversity of freshwater fungi  

Microsoft Academic Search

There are more than 600 species of freshwater fungi with more known from temperate, as compared to tropical regions. These includeca 340 ascomycetes, 300 deuteromycetes, and a number of lower fungi which are not discussed here.Aniptodera, Annulatascus, Massarina, Ophioceras andPseudohalonectria are common freshwater ascomycetes, which appear to be well adapted for this lifestyle either in their ascospore types or their

T K Goh; K D Hyde

1996-01-01

184

Conserving Madagascar's Freshwater Biodiversity  

NSDL National Science Digital Library

This peer-reviewed article from BioScience is about conserving freshwater diversity in Madagascar. The island nation of Madagascar, an international conservation priority, is now also recognized as a global hotspot for freshwater biodiversity. Three emerging characteristics of Madagascar's threatened freshwater biota deserve increased attention from the scientific and conservation communities. First, species richness is not low, as was once assumed for both the freshwater fishes and the invertebrates. Second, many species are restricted to a specific region or even to single river basins. Often these species are also limited to streams or rivers draining primary forest habitat. Finally, many of the island's freshwater fishes are basal taxa, having diverged earlier than any other extant members of their clade. As such, these taxa assume disproportional phylogenetic importance. In the face of ongoing environmental threats, links among microendemism, forest stream specialization, and basal phylogenetic position highlight the importance and vulnerability of these species and provide a powerful incentive for immediate conservation action.

JONATHAN P. BENSTEAD, PATRICK H. DE RHAM, JEAN-LUC GATTOLLIAT, FRANÃ?OIS-MARIE GIBON, PAUL V. LOISELLE, MICHEL SARTORI, JOHN S. SPARKS, and MELANIE L. J. STIASSNY (; )

2003-11-01

185

Long-term effects of ammonia on the behavioral activity of the aquatic snail Potamopyrgus antipodarum (Hydrobiidae, Mollusca).  

PubMed

An appropriate approach to assess the effect of toxicants on aquatic animals is to monitor behavioral endpoints, as they are a link between physiological and ecological processes. A group that can be exposed long-term to low toxic concentrations is benthic macroinvertebrates, as their mobility in aquatic ecosystems is relatively limited. Therefore, the study of behavioral long-term effects in this group is suitable from an ecological point of view, as behavioral effects can appear before mortality. During the last decades there has been an increase in ammonia concentrations in freshwater ecosystems, threatening aquatic animals. The present study focuses on the long-term effects (40 days) of nonionized ammonia on the behavioral activity of the aquatic snail Potamopyrgus antipodarum. One control and three ammonia concentrations (0.02, 0.07, and 0.13 mg N-NH(3)/L) were used in triplicate, and the activity of snails (as mean time to start normal movement) and immobility were recorded for each treatment after 0, 10, 20, 30, and 40 days of continuous exposure to nonionized ammonia. The results show that P. antipodarum presented a high tolerance to lethal long-term effects of nonionized ammonia, as no animal died during the bioassay. However, the behavioral activity of snails was a very sensitivity endpoint, as a mean nonionized ammonia concentration of 0.07 mg N-NH(3)/L affected P. antipodarum. The results are discussed and compared with the available literature on long-term effects of ammonia on freshwater macroinvertebrates. Additionally, the ammonia water quality criteria, NOECs, LOECs, and long-term LCs are discussed on the basis of the current available data for freshwater macroinvertebrates. PMID:19039513

Alonso, Alvaro; Camargo, Julio A

2009-05-01

186

Successful parasitism of vector snail Biomphalaria glabrata by the human blood fluke (trematode) Schistosoma mansoni: a 2009 assessment  

PubMed Central

Schistosomiasis, caused by infections by human blood flukes (Trematoda), continues to disrupt the lives of over 200,000,000 people in over 70 countries, inflicting misery and precluding the individuals’ otherwise reasonable expectations of productive lives. Infection requires contact with freshwater in which infected snails (the intermediate hosts of schistosomes) have released cercariae larvae. Habitats suitable for the host snails continue to expand as a consequence of water resource development. No vaccine is available, and the emergence and spread of resistance to the single licensed schistosomicide drug would be devastating. Since human infections would cease if parasite infections in snails were prevented, efforts are being made to discover requirements of intra-molluscan development of these parasites. Wherever blood flukes occur, naturally resistant conspecific snails are present. To understand the mechanisms used by parasites to ensure their survival in immunocompetent hosts, one must comprehend the internal defense mechanisms that are available to the host. For one intermediate host snail (Biomphalaria glabrata) and trematodes for which it serves as vector, molecular genetic and proteomic surveys for genes and proteins influencing the outcomes on infections are yielding lists of candidates. A comparative approach drawing on data from studies in divergent species provides a robust basis for hypothesis generation to drive decisions as to which candidates merit detailed further investigation. For example, reactive oxygen and nitrogen species are known mediators or effectors in battles between infectious agents and their hosts. An approach targeting genes involved in relevant pathways has been fruitful in the Schistosoma mansoni-B. glabrata parasitism, leading to discovery of a functionally relevant gene set (encoding enzymes responsible for the leukocyte respiratory burst) that associates significantly with host resistance phenotype. This review summarizes advances in the understanding of strategies used by both this trematode parasite and its molluscan host to ensure their survival. PMID:19393158

Bayne, Christopher J.

2009-01-01

187

Mate desertion in the snail kite  

USGS Publications Warehouse

Mate desertion during the breeding cycle was documented at 28 of 36 (78%) snail kite, Rostrhamus sociabilis nests in Florida between 1979 and 1983. Offspring mortality occurred at only one deserted nest, however. Parents that were deserted by their mates continued to care for their young until independence (3?5 additional weeks) and provided snails at a rate similar to that of both parents combined before desertion. Males and females deserted with nearly equal frequency, except in 1982 when more females deserted. No desertion occurred during drought years, whereas desertion occurred at nearly every nest during favourable conditions. The occurrence of mate desertion was generally related to indirect measures of snail abundance: foraging range, snail delivery rates to the young and growth rates. Small broods were deserted more frequently by females than by males and tended to be deserted earlier than large ones. After desertion, deserters had the opportunity to re-mate and nest again since breeding seasons were commonly lengthy, but whether they did so was impossible to determine conclusively in most cases. The deserted bird sometimes incurred increased energetic costs and lost breeding opportunities during periods of monoparental care.

Beissinger, S.R.; Snyder, N.F.R.

1988-01-01

188

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

189

The Dispersal of Snails by Birds  

Microsoft Academic Search

I WAS present at a meeting of the Malacological Society last May when Dr. Boycott read a very interesting paper, in which he showed how the small snail Balea perversa occurred on trees, walls, and rocks, but not on the ground. The question arose how it got from tree to tree; and in the resulting discussion the fact was brought

T. D. A. Cockerell

1921-01-01

190

Transboundary Freshwater Dispute Database  

NSDL National Science Digital Library

This collection of databases is intended to aid in the assessment of the process of water conflict prevention and resolution. The searchable collections include data such as case studies, freshwater treaties from 1820 to 2001, events concerning historical water relations from 1948 to 1999, a register of international river basins, and information on interstate water compacts in the United States. There is also spatial data on transboundary freshwater indicator variables, international river basins, and a map and image gallery. Other materials include links to the organization's publications and research projects, and a set of links to other databases and publications on freshwater conflict issues.

191

Embryogenesis and the effects of temperature on embryonic development, juvenile growth rates, and the onset of oviposition in the fresh-water pulmonate gastropod Physella cubensis  

Microsoft Academic Search

Embryonic development in Physella cubensis is similar to that in other members of Physella, although trochophore or veliger-like embryonic stages previously noted in P. gyrina were lacking. Egg masses of adults collected from Shades Creek, Birmingham, Alabama were subjected to three temperature treatments (10, 20 and 30°C) within the normal range of temperatures experienced in the field, and developmental stages

DONALD L. THOMAS; JAMES B. McCLINTOCK

1990-01-01

192

Transatlantic Freshwater Aqueduct  

Microsoft Academic Search

This paper offers a technical and geopolitical reappraisal of a macro-engineering proposal to plumb Earth’s freshwater, siphoning\\u000a some of it from a region of surplus (Amazon River Basin) to a region of shortage (arid northern Africa) via his positively buoyant (subsurface floating) seabed-anchored Transatlantic Freshwater Aqueduct. Two different routes for\\u000a the pipeline, of length 4,317 and 3,745 km, respectively, have been

Viorel Badescu; Dragos Isvoranu; Richard B. Cathcart

2010-01-01

193

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

194

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

195

Estrogen alters the profile of the transcriptome in river snail Bellamya aeruginosa.  

PubMed

We evaluated the transcriptome dynamics of the freshwater river snail Bellamya aeruginosa exposed to 17?-estradiol (E2) using the Roche/454 GS-FLX platform. In total, 41,869 unigenes, with an average length of 586 bp, representing 36,181 contigs and 5,688 singlets were obtained. Among them, 18.08, 36.85, and 25.47 % matched sequences in the GenBank non-redundant nucleic acid database, non-redundant protein database, and Swiss protein database, respectively. Annotation of the unigenes with gene ontology, and then mapping them to biological pathways, revealed large groups of genes related to growth, development, reproduction, signal transduction, and defense mechanisms. Significant differences were found in gene expression in both liver and testicular tissues between control and E2-exposed organisms. These changes in gene expression will help in understanding the molecular mechanisms of the response to physiological stress in the river snail exposed to estrogen, and will facilitate research into biological processes and underlying physiological adaptations to xenoestrogen exposure in gastropods. PMID:25398503

Lei, Kun; Liu, Ruizhi; An, Li-Hui; Luo, Ying-Feng; LeBlanc, Gerald A

2015-03-01

196

Epiphragmin, the major protein of epiphragm mucus from the vineyard snail, Cernuella virgata.  

PubMed

The organic fraction of epiphragm mucus from the snail Cernuella virgata (Mollusca: Helicidae) consists predominantly of protein (17-23 dry wt.%) rather than carbohydrate (< or =0.4-2.0 dry wt.%), and the former underpins epiphragm membrane structure. The major protein ('epiphragmin') has an apparent molecular mass of approximately 86 kDa and is encoded by a cDNA (Genbank accession EF602752) which specifies a secreted protein of 81.2 kDa. The central region of the epiphragmin polypeptide is a coiled coil-forming region which is homologous to part of AglZ, a bacterial filament-forming protein. Coiled coil-driven self-assembly of epiphragmin probably underpins the formation of sheets in epiphragm membranes and the ability of epiphragm mucus to serve as an adhesive. The C-terminal region of epiphragmin is a fibrinogen-related domain (FReD) that is homologous to the fibrinogen-related proteins (FREPs) found in the hemolymph of freshwater snails. The material properties of epiphragm membranes resemble those of bovine ligament elastin. Wooden lap-joints bonded by rehydrated epiphragm fragments developed dry shear strength values of 1.4+/- 0.1 MPa. PMID:17604201

Li, Dongmei; Graham, Lloyd D

2007-10-01

197

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

198

The Biological Control of the Snail Hosts of Schistosomes: The Role of Competitor Snails and Biological Invasions  

Microsoft Academic Search

\\u000a Biological control of the snail hosts of schistosomes has been ­considered in the last few decades as an alternative to molluscicides.\\u000a Several groups of organisms have been proposed to control snail hosts, but very few have proven their efficacy in the field.\\u000a Competitor snails can be considered as the most efficient biological control agents and numerous promising laboratory studies\\u000a and

Jean-Pierre Pointier; Patrice David; Philippe Jarne

199

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

200

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.

201

Barriers, repellents and antifeedants for slug and snail control  

Microsoft Academic Search

Laboratory bioassays were carried out to evaluate the efficacy of various products with potential for slug and snail control in horticulture and agriculture. The products tested were cinnamamide, copper ammonium carbonate, garlic, aluminium and copper foil, a mulch, ureaformaldehyde and the proprietary products SnailBan® and Tex-R® matting. The trials were carried out using the slug Deroceras panormitanum (Lessona and Pollonera,

I Schüder; G. Port; J. Bennison

2003-01-01

202

Images of Minute Minnesota Land Snails Matt Barthel  

E-print Network

at the University of Wisconsin-Green Bay (UWGB). The shells imaged were assigned to species (or subspecies) based Scanning Electron Microscope (SEM). The snails were imaged in N-SEM mode at a vacuum of 10 Pa collection and lab processing of samples containing the shells. Students enrolled in the land snail practicum

Nekola, Jeffrey C.

203

Carthusian snail Monacha cartusiana Michigan State University's invasive species factsheets  

E-print Network

Carthusian snail Monacha cartusiana Michigan State University's invasive species factsheets as a prohibited mollusk species by Michigan's plant protection regulations (MDA 2009). Plant hosts A wide variety plants. In addition, invasive snails can potentially transmit plant and animal pathogens and displace

204

Slime-Trail Tracking in the Predatory Snail, Euglandina rosea  

Microsoft Academic Search

Euglandina rosea, a predatory land snail, tracks prey and mates by following slime trails. Euglandina follow slime trails more than 80% of the time, following trails of their own species, but not those of prey snails, in the direction that they were laid. The attractive elements of prey slime are small, water-soluble compounds detected by specialized lip extensions. Although olfaction

Kavan T. Clifford; Liaini Gross; Kwame Johnson; Khalil J. Martin; Nagma Shaheen; Melissa A. Harrington

2003-01-01

205

The Snail Resource of the Eastern Berin9 Sea  

E-print Network

; potential resources, like east- ern Bering Sea snails, are virtually un- known. Several species of large. Japan has harvested snails in the eastern Bering Sea since the early 1970's and there is potential for the development of a U.S. domestic fishery ABSTRACT-A trawl survey in the east- ern Bering Sea outlined

206

Phenotypic plasticity of the introduced New Zealand mud snail, Potamopyrgus antipodarum, compared to sympatric native snails.  

PubMed

Phenotypic plasticity is likely to be important in determining the invasive potential of a species, especially if invasive species show greater plasticity or tolerance compared to sympatric native species. Here in two separate experiments we compare reaction norms in response to two environmental variables of two clones of the New Zealand mud snail, Potamopyrgus antipodarum, isolated from the United States, (one invasive and one not yet invasive) with those of two species of native snails that are sympatric with the invader, Fossaria bulimoides group and Physella gyrina group. We placed juvenile snails in environments with high and low conductivity (300 and 800 mS) in one experiment, and raised them at two different temperatures (16 °C and 22 °C) in a second experiment. Growth rate and mortality were measured over the course of 8 weeks. Mortality rates were higher in the native snails compared to P. antipodarum across all treatments, and variation in conductivity influenced mortality. In both experiments, reaction norms did not vary significantly between species. There was little evidence that the success of the introduced species is a result of greater phenotypic plasticity to these variables compared to the sympatric native species. PMID:24699685

Levri, Edward P; Krist, Amy C; Bilka, Rachel; Dybdahl, Mark F

2014-01-01

207

Phenotypic Plasticity of the Introduced New Zealand Mud Snail, Potamopyrgus antipodarum, Compared to Sympatric Native Snails  

PubMed Central

Phenotypic plasticity is likely to be important in determining the invasive potential of a species, especially if invasive species show greater plasticity or tolerance compared to sympatric native species. Here in two separate experiments we compare reaction norms in response to two environmental variables of two clones of the New Zealand mud snail, Potamopyrgus antipodarum, isolated from the United States, (one invasive and one not yet invasive) with those of two species of native snails that are sympatric with the invader, Fossaria bulimoides group and Physella gyrina group. We placed juvenile snails in environments with high and low conductivity (300 and 800 mS) in one experiment, and raised them at two different temperatures (16°C and 22°C) in a second experiment. Growth rate and mortality were measured over the course of 8 weeks. Mortality rates were higher in the native snails compared to P. antipodarum across all treatments, and variation in conductivity influenced mortality. In both experiments, reaction norms did not vary significantly between species. There was little evidence that the success of the introduced species is a result of greater phenotypic plasticity to these variables compared to the sympatric native species. PMID:24699685

Levri, Edward P.; Krist, Amy C.; Bilka, Rachel; Dybdahl, Mark F.

2014-01-01

208

Implications of water hardness in ecotoxicological assessments for water quality regulatory purposes: a case study with the aquatic snail Biomphalaria glabrata (Say, 1818).  

PubMed

Water hardness is a property depending on the presence of alkaline earth metals, mainly calcium and magnesium. Among the strategies for water quality monitoring, ecotoxicological assays are performed to minimize impacts and classify water bodies. For these laboratory evaluations parameters are previously defined in the guidelines, including water hardness for both cultivation and testing medium. The present work was performed to evaluate the effects of different levels of water hardness on the survival and reproduction of the freshwater snail Biomphalaria glabrata and discuss the influence of natural water hardness on the results of ecotoxicological tests with these environmental samples. Comparing the groups it was possible to observe that those maintained in waters with least hardness had lower reproductive success, while the groups maintained in highest hardness showed better reproduction. These data show that waters with low hardness make the reproduction of the snail B. glabrata unfeasible, and this reveal a problem for ecotoxicity assays using natural water samples. PMID:25055099

Oliveira-Filho, E C; Caixeta, N R; Simplício, N C S; Sousa, S R; Aragão, T P; Muniz, D H F

2014-02-01

209

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

210

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

211

nonindigenous freshwater bryozoans  

Microsoft Academic Search

Aim The transport of organisms in ships' ballast tanks is a dominant vector for aquatic invasions worldwide. Until recently, efforts to manage this vector have overlooked the potential transport of invertebrate resting stages in the residual waters and sediments within emptied ballast tanks, i.e. NOBOB ('No Ballast On Board') tanks. The resting stages (statoblasts) of freshwater bryozoans are often buoyant

R. Kipp; S. A. Bailey; H. J. MacIsaac; A. Ricciardi

2010-01-01

212

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

213

A magazine providing a snapshot of the latest developments across the chemical Substitutes for snail slime  

E-print Network

. Substitutes for snail slime 20 March 2007 A team of engineers set a small robot climbing walls in order to compare how natural and artificial snail slimes work. A snail's slime acts as both a glue and a lubricant and repair works in natural snail slime and in synthetic slimes based on clay and polymers. They calculated

214

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..

215

Freshwater Pollution and Treatment  

NSDL National Science Digital Library

This teaching resource was developed by a K-12 science teacher in the American Physiological SocietyÃÂs 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

216

Zooplankton, fish and fisheries in tropical freshwaters  

Microsoft Academic Search

About 40% of all fish species occur in freshwater, although only 1% of the globe is occupied by freshwaters. The tropics harbour a high percentage of these fishes. Freshwater zooplankton on the other hand is far less diverse than its marine counterpart and the tropics do not harbour a markedly high percentage of freshwater species either. The antecedents of freshwater

C. H. Fernando

1994-01-01

217

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

218

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

219

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

220

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

221

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...

222

Evolutionary aspects of population structure for molecular and quantitative traits in the freshwater snail Radix balthica  

E-print Network

, migration and drift shape the genetic divergence of natural populations. Measuring the relative importance over alternative approaches. First, it gives information on the nature of selection (directional vs). Thirdly, detecting the action of selection in natural populations can be based on the measurement

Alvarez, Nadir

223

High tolerance to abiotic stressors and invasion success of the slow growing freshwater snail, Melanoides tuberculatus  

Microsoft Academic Search

Considerable research has been conducted to determine traits common to invasive species with the goal of predicting, preventing,\\u000a or managing invasions. The importance of physiological tolerance to abiotic stressors in the ability of invasive species to\\u000a establish and displace native species has been hypothesized to be important although there are few actual tests of the hypothesis\\u000a in the literature. In

Scott M. WeirChristopher; Christopher J. Salice

224

Effects of Acid Water on Shells, Embryos, and Juvenile Survival of Planorbella trivolvis (Gastropoda: Pulmonata): A Laboratory Study  

Microsoft Academic Search

Adults of the freshwater pulmonate snail Planorbella trivolvis were maintained in aquaria at four pH levels of approximately 4.9, 5.9, 6.8 and 7.8. Adult mortality was moderate over 82 days (10–32%) and not related to the magnitude of pH reduction. Decrease in both shell calcium per unit tissue dry weight and shell calcium per unit maximum shell diameter were significantly

R. Douglas Hunter

1988-01-01

225

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

226

Snails, stable iostopes, and southwestern desert paleoclimates  

SciTech Connect

Modern and fossil molluscs (snails) occur in many localities in and semi-arid regions throughout the desert southwest. Live terrestrial snails are found under rocks and in forest litter and aquatic taxa inhabit springs, seeps, and/or wetlands. Molluscs uptake local water during their growing season (spring and summer) and incorporate its delta 180 signature into their shells. Preliminary 180 analysis of modem shells from the southern Great Basin indicates that the shells probably reflect meteoric water 180 values during the growing season. This provides a way to estimate the delta 180 value of precipitation and, thereby, the source of the moisture-bearing air masses. Significant 180 variability in shells analyzed include geographic location, elevation, taxonomy, and habitat (terrestrial, spring, or wetland). We found a rough inverse correlation with elevation in modem shells from the Spring Range in southern Nevada. The delta 180 values of modem and fossil shells are also very different; modem values in this location are much higher than those from nearby late Pleistocene-age molluscs suggesting that the Pleistocene summers were variously colder and wetter than today or less evaporative (more humid). Assuming shell material directly reflects the 180 of the growing-season environment, comparison of modem and fossil shell delta 180 values can potentially identify changes in air-mass moisture sources and can help to define seasonal precipitation change through time. Comprehension and quantification of community and isotopic variability in modem gastropods is required to create probabilistic valid transfer functions with fossil materials. Valid inferences about past environmental conditions can then be established with known confidence limits.

Sharpe, S.E. [Univ. and Community College System of Nevada, Reno, NV (United States); Whelan, J.F.; Forester, R.M.; Burdett, J.

1995-09-01

227

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

228

Respiration rates and population metabolism of woodland snails  

Microsoft Academic Search

Experiments were done to measure the respiration rates of twenty species of terrestrial snail. Acclimatization phenomena were sought in two species, Discus rotundatus and Hygromia striolata, but not detected. The Q10s between 5 and 15° C for the twenty species varied between 1.20 and 4.27, with a mean Q10 of 2.21. Q10 was higher in larger snail species. There was

C. F. Mason; Botanic Gardens

1971-01-01

229

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

230

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.

231

Heavy metal accumulation in sediment and freshwater fish in U.S. Arctic lakes  

SciTech Connect

Metal concentrations in sediment and two species of freshwater fish (lake trout [Salvelinus namaycush], and grayling [Thymallus arcticus]) were examined in four Arctic lakes in Alaska. Concentrations of several metals were naturally high in the sediment relative to uncontaminated lakes in other Arctic regions and more temperate locations. For example, concentrations of Hg and Ni were 175 ng/g and 250 ng/g dry weight, respectively, in Feniak Lake surface sediment. If any anthropogenic enrichment has occurred, it is not distinguishable from background variability based on surface sediment to down core comparisons. With the exception of Hg, the site rank order of metal concentrations (Cu, Cd, Ni, Pb, and Zn) in sediment and freshwater fish tissue among lakes is not consistent. This suggests that a number of physical, chemical, and physiological parameters mediate metal bioavailability and uptake in these systems. Maximum concentrations of most metals in fish from this study are equal to or higher than those collected from remote Arctic lakes and rivers in Canada, Finland, and Russia. Muscle Hg concentrations in excess of 1 {micro}g/g wet weight were observed in lake trout from Feniak Lake, which has no identified Hg source other than naturally Hg-enriched sediments. Fish diet seems to influence some heavy metal burdens, as evidenced by the higher concentrations of some metals in lake trout compared to grayling, and differences among lakes for lake trout. Cadmium, Cu, and Zn burdens were higher in lakes where snails were consumed by trout compared to lakes without snails.

Allen-Gil, S.M. [Oregon State Univ., Corvallis, OR (United States). Dept. of Fisheries and Wildlife; Gubala, C.P. [Utah State Univ., Logan, UT (United States); Landers, D.H. [Environmental Protection Agency, Corvallis, OR (United States). National Health and Environmental Effects Research Lab.; Lasorsa, B.K.; Crecelius, E.A. [Battelle Pacific Northwest Div., Sequim, WA (United States); Curtis, L.R. [East Tennessee State Univ., Johnson City, TN (United States)

1997-04-01

232

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

233

Marine and freshwater toxins.  

PubMed

In a very busy and exciting year, 2005 included First Action approval of a much needed official method for paralytic shellfish toxins and multiple international toxin symposia highlighted by groundbreaking research. These are the first-year milestones and activities of the Marine and Freshwater Toxins Task Force and Analytical Community. Inaugurated in 2004 and described in detail in last year's General Referee Report (1) this international toxins group has grown to 150 members from many regions and countries. Perhaps most important they are now making important and global contributions to food safety and to providing alternatives to animal-based assays. Official Method 2005.06 was first approved in late 2004 by the Task Force and subsequently Official First Action in 2005 (2) by the Methods Committee on Natural Toxins and Food Allergens and the Official Methods Board. This nonproprietary method (3) is a precolumn oxidation, liquid chromatographic method that makes good use of fluorescence detection to provide high sensitivity detection of the saxitoxins. It has also proven to be rugged enough for regulatory use and the highest level of validation. As pointed out in the report of method principle investigator and Study Director James Lawrence, approval of 2005.06 now provides the first official alternative to the mouse bioassay after many decades of shellfish monitoring. This past year in April 2005 the group also held their first international conference, "Marine and Freshwater Toxins Analysis: Ist Joint Symposium and AOAC Task Force Meeting," in Baiona, Spain. The 4-day conference consisted of research and stakeholder presentations and symposium-integrated subgroup sessions on ciguatoxins, saxitoxin assays and liquid chromatography (LC) methods for saxitoxins and domoic acids, okadaiates and azaspiracids, and yessotoxins. Many of these subgroups were recently formed in 2005 and are working towards their goals of producing officially validated analytical methods. (Abstracts from the Baiona 2005 meeting cited in this report can be found in the online version of the conference abstract book in the Files and Folders section of the Marine and Freshwater Toxins online community at www.aoac.org.) An active topic for discussion in Baiona and subsequent Task Force activities was the expert consultation for Codex which met in Oslo, Norway in 2004 (previously described and cited in last year's GR report, ref 1). The consultation group's executive summary report (http://www.fao.org/es/ESN/food/risk_biotoxin en.stm) describes suggested changes in action levels as well as methods, method validation, and other issues. September 2005 saw the AOAC Task Force efforts further supported by another symposium, "Marine and Freshwater Toxins: Quality Methods for Food Safety and International Trade," at the AOAC INTERNATIONAL Annual Conference in Orlando, Florida. The multidisciplinary talks at this full day symposium ranged from ciguatoxins to cyanobacterial toxins, and spanned toxicology, biochemistry, molecular biology and analytical chemistry. Again, the symposium preceded Task Force meetings. Toxin subgroups, including a new group on cyanobacterial toxins, met for engaging and productive subgroup discussions. All of these activities were preceded by a Wiley Award symposium for Task Force member Mike Quilliam of NRC Canada. These talks, presented at a half-day symposium on the first day of the Annual Meeting, focused on Quilliam's work with LC tandem mass spectrometry (LC/MS/MS) and certified reference standards and materials, and included related presentations by some of his many research collaborators. To maintain flow and continuity between symposia and between Task Force meetings, the group now uses new electronic discussion forums. Individual subgroup areas, under the Marine and Freshwater Toxins Task Force, comprise this online community. First introduced by AOAC INTERNATIONAL in early 2005, these new resources are being used to distribute information and to supplement the in-person subgroup meetings and electroni

Hungerford, James M

2006-01-01

234

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

235

Vineyard snail allergy possibly induced by sensitization to house-dust mite (Dermatophagoides pteronyssinus).  

PubMed

A female patient experienced a severe allergic reaction after consumption of vineyard snails. The patient proved to be sensitized to house-dust mite (HDM) and demonstrated a positive skin test and specific IgE to snail (Eobania vermiculata, Lofarma). The snail RAST was > 80% inhibited by HDM, whereas the mite RAST was < 10% inhibited by snail extract. This is possibly another example of food allergy related to primary sensitization by an aeroallergen. PMID:7573833

De Maat-Bleeker, F; Akkerdaas, J H; van Ree, R; Aalberse, R C

1995-05-01

236

Copper uptake and depuration by juvenile and adult Florida apple snails ( Pomacea paludosa )  

Microsoft Academic Search

The present study characterized copper (Cu) uptake and depuration by juvenile and adult Florida apple snails (Pomacea paludosa) from water, soil, and diet. During a 28-day uptake period, juvenile apple snails were exposed to aqueous Cu and adult apple\\u000a snails were exposed to Cu-contaminated soil, water, and food. In the follow-up 14-day depuration period, both juvenile and\\u000a adult apple snails

Tham C. Hoang; Emily C. Rogevich; Gary M. Rand; Robert A. Frakes

2008-01-01

237

The Neogastropoda: Evolutionary Innovations of Predatory Marine Snails with Remarkable Pharmacological Potential  

Microsoft Academic Search

\\u000a The Neogastropoda include many familiar molluscs, such as cone snails (Conidae), purple dye snails (Muricidae), mud snails\\u000a (Nassariidae), olive snails (Olividae), oyster drills (Muricidae), tulip shells (Fasciolariidae), and whelks (Buccinidae).\\u000a Due to their amazing predatory specializations, neogastropods are often dominant members of the benthic community at the top\\u000a of the food chain. In a dazzling display that ranges from boring

Maria Vittoria Modica; Mandë Holford

238

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

239

Implication of Snail in Metabolic Stress-Induced Necrosis  

PubMed Central

Background Necrosis, a type of cell death accompanied by the rupture of the plasma membrane, promotes tumor progression and aggressiveness by releasing the pro-inflammatory and angiogenic cytokine high mobility group box 1. It is commonly found in the core region of solid tumors due to hypoxia and glucose depletion (GD) resulting from insufficient vascularization. Thus, metabolic stress-induced necrosis has important clinical implications for tumor development; however, its regulatory mechanisms have been poorly investigated. Methodology/Principal Findings Here, we show that the transcription factor Snail, a key regulator of epithelial-mesenchymal transition, is induced in a reactive oxygen species (ROS)-dependent manner in both two-dimensional culture of cancer cells, including A549, HepG2, and MDA-MB-231, in response to GD and the inner regions of a multicellular tumor spheroid system, an in vitro model of solid tumors and of human tumors. Snail short hairpin (sh) RNA inhibited metabolic stress-induced necrosis in two-dimensional cell culture and in multicellular tumor spheroid system. Snail shRNA-mediated necrosis inhibition appeared to be linked to its ability to suppress metabolic stress-induced mitochondrial ROS production, loss of mitochondrial membrane potential, and mitochondrial permeability transition, which are the primary events that trigger necrosis. Conclusions/Significance Taken together, our findings demonstrate that Snail is implicated in metabolic stress-induced necrosis, providing a new function for Snail in tumor progression. PMID:21448462

Ju, Min Kyung; Moon, Ji Young; Park, Hye Gyeong; Yoo, Mi-Ae; Choi, Byung Tae; Yook, Jong In; Lim, Sung-Chul; Han, Song Iy; Kang, Ho Sung

2011-01-01

240

New scope on the relationship between rotifers and Biomphalaria alexandrina snails  

PubMed Central

Objective To investigate the effect of rotifer internalization into snail tissue on the development of schistosomes. Methods Susceptible laboratory-bred Biomphalaria alexandrina (B. alexandrina) snails were exposed to lab-maintained rotifers; Philodina spp., two weeks before and after being infected with Schistosoma mansoni (S. mansoni) miracidia. The consequent histopathological impact on snail tissues and cercarial biology were investigated before and after emergence from snails. Results Contamination of B. alexandrina snails with philodina, two weeks before miracidial exposure, was found to hinder the preliminary development of S. mansoni cercariae inside the snail tissues. Furthermore, when snails were contaminated with rotifers two weeks post miracidial exposure; growth of already established cercariae was found to be retarded. The consequent influence of internalized rotifers within the snail tissue was clearly reflected on cercarial emergence, activity and infectivity along the four weeks duration of shedding. In the present study, comparison of snail histopathological findings and altered cercarial biology observed between the experimental and control groups indicated that the rotifers may have affected the levels of snail's energy reservoirs, which eventually was found to have had an adverse impact on reproduction, growth and survival of the parasite within the snail host, coupled with its performance outside the snail. Conclusions In future biological control strategies of schistosomiasis, ritifers should be considered as a parasitic scourge of humanity. PMID:23905015

Mossallam, Shereen Farouk; Amer, Eglal Ibrahim; Abou-El-Naga, Iman Fathy

2013-01-01

241

Helix and Drugs: Snails for Western Health Care From Antiquity to the Present  

PubMed Central

The land helix, or snail, has been used in medicine since antiquity and prepared according to several formulations. This historical report traces the understanding of their properties from the time of Hippocrates, who proposed the use of snail mucus against protoccle and Pliny who thought that the snail increased the speed of delivery and was “a sovereign remedy to treat pain related to burns, abscesses and other wounds”, Galien recommended snails against hydrops foetails. In the 18th century, various snail “preparations” were also recommended for external use with dermatological disorders and internally for symptoms associated with tuberculosis and nephritis. Surprisingly, the 19th century saw a renewed interest in the pharmaceutical and medical use of snails with numerous indications for snail preparations. This interest in snails did not stop at the end of the 19th century. The 1945 edition of Dorvault devotes an entire paragraph to snails, indicating that the therapeutic usage of snails was still alive at that time. Recently the FDA has also shown an interest in snails. Ziconotide (SNXIII), a synthetic peptide coming from snail venom, has been under FDA review since 1999. Pre-clinical and clinical studies of this new drug are promising. PMID:15841274

2005-01-01

242

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

243

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

244

Slime-trail tracking in the predatory snail, Euglandina rosea.  

PubMed

Euglandina rosea, a predatory land snail, tracks prey and mates by following slime trails. Euglandina follow slime trails more than 80% of the time, following trails of their own species, but not those of prey snails, in the direction that they were laid. The attractive elements of prey slime are small, water-soluble compounds detected by specialized lip extensions. Although olfaction plays no role in trail following, strong odors disrupt tracking. Inhibition of nitric oxide synthase also disrupts slime trail following, suggesting a role for nitric oxide in neural processing of slime trail stimuli. Euglandina can be conditioned to follow novel trails of glutamate or arginine paired with feeding on prey snails. These experiments demonstrate that slime-trail tracking in Euglandina is a robust, easily measured behavior that makes a good model system for studying sensory processing and learning in a novel modality. PMID:14570557

Clifford, Kavan T; Gross, Liaini; Johnson, Kwame; Martin, Khalil J; Shaheen, Nagma; Harrington, Melissa A

2003-10-01

245

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...

246

Influence of snail feces and mucus on oviposition and larval behavior ofPherbellia cinerella (Diptera: Sciomyzidae).  

PubMed

Larvae of the sciomyzid flyPherbellia cinerella are voracious predators of terrestrial helicid snails. Eggs are deposited in areas where snails occur and larvae hunt actively for their prey. Snail feces and mucus were tested to determine if they had any kairomone or stimulatory effects onP. cinerella. Adult flies oviposited more frequently on substrates containing fresh snail feces than on substrates containing snail mucus or water (control). However, mucus and feces both stimulated increased search behaviour in first instar larvae. These results are discussed in relation to snail biology, and the potential for augmentation of these flies in areas affected by pest snails. PMID:24227402

Coupland, J B

1996-02-01

247

[Schistosomiasis mansoni and distribution of freshwater mollusks in natural bodies of water in Niterói, Rio de Janeiro State, Brazil].  

PubMed

The authors report on the distribution of freshwater mollusks in Niterói, Rio de Janeiro State, Brazil, and notification of schistosomiasis cases in this municipality from 1995 to 2000. All breeding sites favorable to freshwater mollusks were surveyed, showing the following species: Antillorbis nordestensis (Lucena, 1954), Biomphalaria straminea (Dunker, 1848), Biomphalaria tenagophila (Orbigny, 1835), Drepanotrema anatinum (Orbigny, 1835), Lymnaea columella Say, 1817, Melanoides tuberculatus (Müller, 1774), Physa cubensis Pfeiffer, 1839, Physa marmorata Guilding, 1828, and Pomacea sordida (Swainson, 1823). Some 3,691 specimens of snail hosts for Schistosoma mansoni Sambon, 1907 were examined by exposure to artificial light and crushing. No S. mansoni cercariae were found, although other types of cercariae were observed. PMID:12244379

Medeiros, Almir de Souza; Cruz, Oswaldo José da; Fernandez, Monica Ammon

2002-01-01

248

Nuclear ubiquitination by FBXL5 modulates Snail1 DNA binding and stability  

PubMed Central

The zinc finger transcription factor Snail1 regulates epithelial to mesenchymal transition, repressing epithelial markers and activating mesenchymal genes. Snail1 is an extremely labile protein degraded by the cytoplasmic ubiquitin-ligases ?-TrCP1/FBXW1 and Ppa/FBXL14. Using a short hairpin RNA screening, we have identified FBXL5 as a novel Snail1 ubiquitin ligase. FBXL5 is located in the nucleus where it interacts with Snail1 promoting its polyubiquitination and affecting Snail1 protein stability and function by impairing DNA binding. Snail1 downregulation by FBXL5 is prevented by Lats2, a protein kinase that phosphorylates Snail1 precluding its nuclear export but not its polyubiquitination. Actually, although polyubiquitination by FBXL5 takes place in the nucleus, Snail1 is degraded in the cytosol. Finally, FBXL5 is highly sensitive to stress conditions and is downregulated by iron depletion and ?-irradiation, explaining Snail1 stabilization in these conditions. These results characterize a novel nuclear ubiquitin ligase controlling Snail1 protein stability and provide the molecular basis for understanding how radiotherapy upregulates the epithelial to mesenchymal transition-inducer Snail1. PMID:24157836

Viñas-Castells, Rosa; Frías, Álex; Robles-Lanuza, Estefanía; Zhang, Kun; Longmore, Gregory D.; García de Herreros, Antonio; Díaz, Víctor M.

2014-01-01

249

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

250

40 CFR 35.1605-3 - Publicly owned freshwater lake.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Publicly owned freshwater lake. 35.1605-3 Section 35.1605-3...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-3 Publicly owned freshwater lake. A freshwater lake that offers public...

2011-07-01

251

40 CFR 35.1605-3 - Publicly owned freshwater lake.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Publicly owned freshwater lake. 35.1605-3 Section 35.1605-3...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-3 Publicly owned freshwater lake. A freshwater lake that offers public...

2013-07-01

252

40 CFR 35.1605-3 - Publicly owned freshwater lake.  

...2014-07-01 false Publicly owned freshwater lake. 35.1605-3 Section 35.1605-3...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-3 Publicly owned freshwater lake. A freshwater lake that offers public...

2014-07-01

253

40 CFR 35.1605-3 - Publicly owned freshwater lake.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Publicly owned freshwater lake. 35.1605-3 Section 35.1605-3...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-3 Publicly owned freshwater lake. A freshwater lake that offers public...

2010-07-01

254

40 CFR 35.1605-3 - Publicly owned freshwater lake.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Publicly owned freshwater lake. 35.1605-3 Section 35.1605-3...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-3 Publicly owned freshwater lake. A freshwater lake that offers public...

2012-07-01

255

Reproductive anomalies in stenoglossan snails related to pollution from marinas.  

PubMed

Over 3090 snails of the dioecious intertidal species Nassarius obsoletus Say were collected from a total of 71 localities. Their reproductive anatomy was examined for a superimposition of male characteristics on to the normal female anatomy, an abnormality called 'imposex'. Imposex was rated numerically in terms of the fraction of the population affected and the intensity of expression in bearer snails. An initial survey of 22 localities in Fairfield and Westport, Connecticut, led to the hypothesis that imposex was related to a substance arising from marinas. This was tested at nine pairs of marina and control localities in Long Island Sound, as well as six pairs along a transect ranging from Rhode Island to Georgia. Imposex scores were significantly higher at the marina locality in every pair. Further confirmation was found in a detailed survey of the estuarine harbor at Southport, Connecticut, which showed that adjacent populations could differ in the amount of imposex to the extent that both the snails and the waters they lived in remained separated by natural or man-made barriers. Imposex has been found in populations of N. obsoletus ranging from Damariscotta, Maine, to Savannah, Georgia, and it has been reported from San Francisco Bay, California. Similar anatomical abnormalities have been reported in at least 27 other species of taenioglossan and stenoglossan snails, extending the range to the Atlantic and Mediterranean coast of Europe and the British Isles. Concern is raised regarding the possible existence of another global pollutant with novel effects on marina biota. PMID:7185869

Smith, B S

1981-02-01

256

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

257

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

258

Land Snail Ecology and Biogeography of Eastern Maine  

E-print Network

to the state fauna (Euconulus alderi, Punctum n.sp., Vertigo cristata, Vertigo malleata, Vertigo morseiLand Snail Ecology and Biogeography of Eastern Maine Vertigo bollesiana Vertigo nylanderi Vertigo in the state (Nesovitrea binneyana, Planogyra asteriscus, Striatura ferrea, Striatura milium, Vertigo

Nekola, Jeffrey C.

259

Snail Shells in a Practical Application of Statistical Procedures  

ERIC Educational Resources Information Center

This paper is based upon a laboratory exercise designed for biology students in secondary schools or those taking introductory biology laboratory courses in colleges and universities. This exercise requires a set of calipers, a calculator and populations of snail shells collected either from the wild or obtained from a biological supply house. The…

Banks, Stephen W.; Shepherd, Deborah K.; Williams-Hart, Tara; Gossett, Dalton R.; Crnkovic, Amanda C.

2007-01-01

260

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

261

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

262

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.

263

Snail2 controls mesodermal BMP/Wnt induction of neural crest  

PubMed Central

The neural crest is an induced tissue that is unique to vertebrates. In the clawed frog Xenopus laevis, neural crest induction depends on signals secreted from the prospective dorsolateral mesodermal zone during gastrulation. The transcription factors Snail2 (Slug), Snail1 and Twist1 are expressed in this region. It is known that Snail2 and Twist1 are required for both mesoderm formation and neural crest induction. Using targeted blastomere injection, morpholino-based loss of function and explant studies, we show that: (1) Snail1 is also required for mesoderm and neural crest formation; (2) loss of snail1, snail2 or twist1 function in the C2/C3 lineage of 32-cell embryos blocks mesoderm formation, but neural crest is lost only in the case of snail2 loss of function; (3) snail2 mutant loss of neural crest involves mesoderm-derived secreted factors and can be rescued synergistically by bmp4 and wnt8 RNAs; and (4) loss of snail2 activity leads to changes in the RNA levels of a number of BMP and Wnt agonists and antagonists. Taken together, these results identify Snail2 as a key regulator of the signals involved in mesodermal induction of neural crest. PMID:21715424

Shi, Jianli; Severson, Courtney; Yang, Jianxia; Wedlich, Doris; Klymkowsky, Michael W.

2011-01-01

264

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

265

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

266

Freshwater and its management in India  

Microsoft Academic Search

India is likely to face a major challenge in the management of freshwater in view of rapidly rising population and increasing agricultural, industrial and other requirements. As the economy of the country is currently witnessing rapid growth, management of freshwater resources becomes all the more important. This paper reviews the status of freshwater resources, their quantity and quality, demands as

Sharad K Jain; Anupma Sharma; Rakesh Kumar

2004-01-01

267

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

268

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.

269

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.

270

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

271

Larval trematode infections in freshwater gastropods from the Albufera Natural Park in Spain.  

PubMed

Malacological samplings were made from January 1994 to December 1996 in the Albufera Natural Park (Valencia, Spain) to trace the dynamics of molluscan populations and the prevalence and intensity of infection by larval trematodes. A total of 10,533 freshwater gastropods belonging to seven species (Lymnaea auricularia, L. truncatula, L. palustris, L. peregra, Bithynia tentaculata, Physa acuta and Gyraulus chinensis) was examined, and 110 (1.04%) were found to harbour some of the nine distinguishable types of cercariae, namely four echinostome cercariae (Hypoderaeum conoideum, Echinoparyphium recurvatum, Euparyphium albuferensis, and Echinostoma sp.), four furcocercous cercariae, and one xiphidiocercous cercaria. This study shows that the composition of the snail and trematode communities may be determined by the particular environmental conditions present and the human intervention in the area. PMID:9639906

Toledo, R; Muñoz-Antolí, C; Pérez, M; Esteban, J G

1998-03-01

272

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

273

Freshwater Turtles of Tropical Australia  

E-print Network

Joseph of the Australian National Wildlife Collection for freely providing museum records, and the many for freshwater turtles of tropical Australia and to construct and populate a database to house the information,871 records from the UC Turtle Tissue Database. Most species distributions were very well supported by good

Canberra, University of

274

Freshwater Sculpins: Phylogenetics to Ecology  

Microsoft Academic Search

Freshwater sculpins (Cottidae) are a diverse and ecologically important component of cool- and coldwater ecosystems throughout the northern hemisphere. More than 60 sculpin species occur in a variety of habitats, and sculpin distributions range from highly localized to widespread. Despite the frequently high biomass of sculpins and their numerous ecosystem functions, the traditional fisheries management emphasis on sport fishes has

Susan B. Adams; David A. Schmetterling

2007-01-01

275

Incidence of Parastrongylus cantonensis larvae in different fresh water snails in Dakahlia Governorate.  

PubMed

Samples of snails were collected from different water bodies in Dakahlia governorate to assess a survey on the naturally infected snails and their infection rate with the Parastrongylus cantonensis larvae. The nematode P. cantonensis is associated in the etiology of eosinophilic meningeoencephalitis of man. Lanistes carinatus showed the highest rate of infection with 19-400 larvae per snail. Biomphalaria alexandrina, B. glabrata, Bulinus truncatus, Lymnaea cailliaudi (natalensis), L. alexandrina, and Cleopatra cyclostomoides were found naturally infected with the larvae of P. cantonensis for the first time in Egypt. The number of larvae per infected snail varied depending on the snail type. The highest rate (39.2%) of infected snails was collected from the end canals at Tanneekh and the lowest in the river Nile (12.5%). PMID:12214935

el-Shazly, A M; el-Hamshary, Eman M; el-Shewy, Khalid M; Rifaat, Manal M A; el-Sharkawy, Iman M A

2002-08-01

276

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

277

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

278

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

279

Identification and characterization of five transcription factors that are associated with evolutionarily conserved immune signaling pathways in the schistosome-transmitting snail Biomphalaria glabrata  

PubMed Central

Innate immunity consists of humoral and cellular components that play a vital role in regulation of defense responses to various pathogens in vertebrates and invertebrates. Recent studies have shown that Rel/DIF (dorsal-related immunity factor), Relish, STAT (signal transducer and activator of transcription (STAT), and CREB (cAMP response element-binding protein) transcription factors associated pathways are evolutionarily conserved across the animal kingdom. Although the primary role and general structure of the pathways in immunity have been revealed in many invertebrates, particularly arthropods, almost nothing is known about those pathways in the freshwater snail Biomphalaria glabrata, an intermediate host of the human blood fluke Schistosoma mansoni, a causative agent of human schistosomiasis. Given the central role of transcription factors (TF) in controlling expression of effector genes, understanding the role of a given TF is essential to obtaining insight into the general function of the corresponding signaling pathway. To better understand the immunity of B. glabrata, we investigated five homologues of TFs that have been shown to be associated with multiple prominent immune signaling pathways based on the considerable data reported from a wide phylogenetic range of animals. In this study we identified and characterized cDNAs of five TFs from B. glabrata, designated BgRelish, BgRel, BgSTAT1, BgSTAT2 and BgCREB, for the first time. Among the five TFs, Relish is first reported in Lophotrochozoa, one of three superphyla in Metazoa. Our identification of class I (BgRelish) and II (BgRel) NF-?B in B. glabrata suggests the two pathways, Toll-like receptor (TLR) and immune deficiency (IMD)-like pathways, are present in the superphylum Lophotrochozoa. Preliminarily expression studies indicate these TF-associated pathways may be involved in the snail's anti-schistosome response. This study not only advances our understanding of the snail defenses, but also provides new perspectives about the evolution of animal immunity. PMID:21696828

Zhang, Si-Ming; Coultas, Kristen A.

2011-01-01

280

Structure of mega-hemocyanin reveals protein origami in snails.  

PubMed

Mega-hemocyanin is a 13.5 MDa oxygen transporter found in the hemolymph of some snails. Similar to typical gastropod hemocyanins, it is composed of 400 kDa building blocks but has additional 550 kDa subunits. Together, they form a large, completely filled cylinder. The structural basis for this highly complex protein packing is not known so far. Here, we report the electron cryomicroscopy (cryo-EM) structure of mega-hemocyanin complexes from two different snail species. The structures reveal that mega-hemocyanin is composed of flexible building blocks that differ in their conformation, but not in their primary structure. Like a protein origami, these flexible blocks are optimally packed, implementing different local symmetries and pseudosymmetries. A comparison between the two structures suggests a surprisingly simple evolutionary mechanism leading to these large oxygen transporters. PMID:25482543

Gatsogiannis, Christos; Hofnagel, Oliver; Markl, Jürgen; Raunser, Stefan

2015-01-01

281

Activity of the mangrove snail Cerithidea decollata (Gastropoda: Potamididae) in a warm temperate South African estuary  

NASA Astrophysics Data System (ADS)

A population of Cerithidea decollata, an intertidal marine gastropod usually found within mangroves, was studied within an area of Juncus kraussii in the upper reaches of the warm temperate Knysna estuary, which is at the southern-most limit of the recorded distribution of this snail. Activity (migratory and homing behaviour, distances travelled during foraging) of the snails was monitored over spring and neap tides in four seasons. Migratory patterns of the snails were affected by season, time of low tide (day vs night), tidal magnitude (spring vs neap) and zonation. In the summer and spring, a greater proportion of snails migrated from J. kraussii leaves onto the mud during the day at spring low tide. During neap tides in these two seasons, most snails did not climb J. kraussii leaves and remained on the mud, which was nearly always exposed. In autumn a few snails only were active and in winter snails were almost completely inactive, probably due to low air temperatures. Snails travelled greater distances on the mud on spring tides, during the diurnal low tides, and in the summer. No snails were found to home to individual J. kraussii leaves; however, homing behaviour was recorded to wooden poles within the Juncus wetland.

Hodgson, Alan N.; Dickens, John

2012-08-01

282

Analysis of Snail1 function and regulation by Twist1 in palatal fusion  

PubMed Central

Palatal fusion is a tightly controlled process which comprises multiple cellular events, including cell movement and differentiation. Midline epithelial seam (MES) degradation is essential to palatal fusion. In this study, we analyzed the function of Snail1 during the degradation of the MES. We also analyzed the mechanism regulating the expression of the Snail1 gene in palatal shelves. Palatal explants treated with Snail1 siRNA did not degrade the MES and E-cadherin was not repressed leading to failure of palatal fusion. Transforming growth factor beta 3 (Tgf?3) regulated Snail1 mRNA, as Snail1 expression decreased in response to Tgf?3 neutralizing antibody and a PI-3 kinase (PI3K) inhibitor. Twist1, in collaboration with E2A factors, regulated the expression of Snail1. Twist1/E47 dimers bond to the Snail1 promoter to activate expression. Without E47, Twist1 repressed Snail1 expression. These results support the hypothesis that Tgf?3 may signal through Twist1 and then Snail1 to downregulate E-cadherin expression during palatal fusion. PMID:23424071

Yu, Wenli; Zhang, Yanping; Ruest, L. Bruno; Svoboda, Kathy K. H.

2013-01-01

283

Fasciola hepatica in Snails Collected from Water-Dropwort Fields using PCR  

PubMed Central

Fasciola hepatica is a trematode that causes zoonosis mainly in cattle and sheep and occasionally in humans. Fascioliasis has been reported in Korea; however, determining F. hepatica infection in snails has not been done recently. Thus, using PCR, we evaluated the prevalence of F. hepatica infection in snails at 4 large water-dropwort fields. Among 349 examined snails, F. hepatica-specific internal transcribed space 1 (ITS-1) and/or ITS-2 markers were detected in 12 snails and confirmed using sequence analysis. Morphologically, 213 of 349 collected snails were dextral shelled, which is the same aperture as the lymnaeid snail, the vectorial host for F. hepatica. Among the 12 F. hepatica-infected snails, 6 were known first intermediate hosts in Korea (Lymnaea viridis and L. ollula) and the remaining 6 (Lymnaea sp.) were potentially a new first intermediate host in Korea. It has been shown that the overall prevalence of the snails contaminated with F. hepatica in water-dropwort fields was 3.4%; however, the prevalence varied among the fields. This is the first study to estimate the prevalence of F. hepatica infection using the vectorial capacity of the snails in Korea. PMID:25548416

Kim, Hwang-Yong; Choi, In-Wook; Kim, Yeon-Rok; Quan, Juan-Hua; Ismail, Hassan Ahmed Hassan Ahmed; Cha, Guang-Ho; Hong, Sung-Jong

2014-01-01

284

The Helix aspersa (Brown Garden Snail) Allergen Repertoire  

Microsoft Academic Search

Background: Ingestion of snails can induce strong asthmatic or anaphylactic responses, mainly in house-dust-mite-sensitized patients. The aim of this study was to identify the Helix aspersa (Hel a), Theba pisana (The p) and Otala lactea (Ota l) allergens and the extent of their cross-reactivity with the Dermatophagoides pteronyssinus (Der p) mite. Patients and Methods: In 60 atopicpatients, skin prick tests

Luís Miguel Lourenço Martins; Gabriel Peltre; Carlos José Fialho da Costa Faro; Euclides Manuel Vieira Pires; Filipe Fernando da Cruz Inácio

2005-01-01

285

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

286

Embryonic Toxin Expression in the Cone Snail Conus victoriae  

PubMed Central

Predatory marine cone snails (genus Conus) utilize complex venoms mainly composed of small peptide toxins that target voltage- and ligand-gated ion channels in their prey. Although the venoms of a number of cone snail species have been intensively profiled and functionally characterized, nothing is known about the initiation of venom expression at an early developmental stage. Here, we report on the expression of venom mRNA in embryos of Conus victoriae and the identification of novel ?- and O-conotoxin sequences. Embryonic toxin mRNA expression is initiated well before differentiation of the venom gland, the organ of venom biosynthesis. Structural and functional studies revealed that the embryonic ?-conotoxins exhibit the same basic three-dimensional structure as the most abundant adult toxin but significantly differ in their neurological targets. Based on these findings, we postulate that the venom repertoire of cone snails undergoes ontogenetic changes most likely reflecting differences in the biotic interactions of these animals with their prey, predators, or competitors. To our knowledge, this is the first study to show toxin mRNA transcripts in embryos, a finding that extends our understanding of the early onset of venom expression in animals and may suggest alternative functions of peptide toxins during development. PMID:21504902

Safavi-Hemami, Helena; Siero, William A.; Kuang, Zhihe; Williamson, Nicholas A.; Karas, John A.; Page, Louise R.; MacMillan, David; Callaghan, Brid; Kompella, Shiva Nag; Adams, David J.; Norton, Raymond S.; Purcell, Anthony W.

2011-01-01

287

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.

2009-08-28

288

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.

289

Plagiorchis elegans (Trematoda) and incompatible snail hosts: implications for snail life history traits and biocontrol of human schistosomiasis.  

PubMed

We examined the effect of Plagiorchis elegans on egg production and survival on Bulinus truncatus and Helisoma trivolvis trivolvis. Both species are incompatible hosts for P. elegans. Helisoma t. trivolvis occurs sympatrically with P. elegans; B. truncatus does not. Overall, P. elegans had no effect on survivorship or egg production in H. t. trivolvis or on the survivorship of B. truncatus. Its effect on egg production in B. truncatus was transitory; egg production was reduced by 50% for 5 wk following exposure but returned to normal thereafter. Neither egg production nor survivorship was affected in adult H. t. trivolvis. Egg production ceased at 14 wk post-exposure (PE), but resumed when the snails were paired. Young H. t. trivolvis also produced eggs after exposure, but later than the adults and only after they had been paired with another snail. This suggests that a need for periodic cross-fertilization in H. t. trivolvis rather than the effect of the parasite is responsible for the cessation of egg production in this species. Survivorship in young H. t. trivolvis was significantly higher in exposed snails between wk 7 to 10 PE than in controls. PMID:19566345

Daoust, Simon P; Mader, Brian J; McLaughlin, J Daniel; Rau, Manfred E

2009-12-01

290

Freshwater Mussels (Hyriidae) of Australasia  

Microsoft Academic Search

\\u000a In Australia, New Guinea, Solomon Islands and New Zealand, freshwater mussels are represented by the families Hyriidae and\\u000a Unionidae. The Hyriidae includes 27 species in 8 genera, in the subfamilies Cucumerunioninae, Hyridellinae, Lortiellinae and\\u000a Velesunioninae (a fifth subfamily, the Hyriinae, is endemic to South America). Two other species (one genus) from New Guinea\\u000a are placed tentatively in the Unionidae.

KEITH F. WALKERI; Maria Byrne; Christopher W. Hickey; David S. Roper

291

Survival of the Faucet Snail after Chemical Disinfection, pH extremes, and Heated Water Bath Treatments  

Microsoft Academic Search

The faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid-Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large-scale mortality among water birds, primarily in the Great Lakes region

Andrew J. Mitchell; Rebecca A. Cole

2008-01-01

292

Temperature Tolerance of Red-Rim Melania Melanoides tuberculatus, an Exotic Aquatic Snail Established in the United States  

Microsoft Academic Search

The red-rim melania Melanoides tuberculatus (family Thiaridae), a tropical, nonindigenous aquatic snail, has become established and is spreading in the United States. Concerns associated with the spread of this snail include its potential to displace native snail populations and to transmit trematodes. Of particular concern is the gill trematode Centrocestus formosanus now found in U.S. commercial and wild fish stocks.

Andrew J. Mitchell; Thomas M. Brandt

2005-01-01

293

Measuring Animal Movements in a Natural Ecosystem: A Mark-Recapture Investigation Using Stream-Dwelling Snails  

ERIC Educational Resources Information Center

In this investigation, students measure and describe movements of animals in a natural ecosystem. Students mark stream-dwelling snails with nail polish, then search for these snails 1-7 days later. Distances and directions moved by recaptured snails are recorded. Simple statistical techniques are used to answer specific research questions and…

Stewart, Timothy W.

2007-01-01

294

Freshwater Protected Areas: Strategies for Conservation  

Microsoft Academic Search

Freshwater species and habitats are among the most threatened in the world. One way in which this growing conservation concern can be addressed is the creation of freshwater protected areas. Here, we present three strategies for freshwater protected-area design and management: whole-catchment management, natu- ral-flow maintenance, and exclusion of non-native species. These strategies are based on the three primary threats

D. L. Saunders; J. J. Meeuwig; A. C. J. Vincent

2002-01-01

295

The detection of snail host habitats in liver fluke infected farms by use of plant indicators  

Microsoft Academic Search

Field investigations in 361 liver fluke infected cattle- or sheep-breeding farms on acid soil were carried out during thirty years in March and April to record indicator plants in relation to the category of site colonized by the intermediate host of liver fluke, the snail Galba truncatula. Seven types of snail zones and six species of indicator plants were recorded

Daniel Rondelaud; Philippe Hourdin; Philippe Vignoles; Gilles Dreyfuss; Jacques Cabaret

2011-01-01

296

Effect of light intensity on Opisthorchis viverrini cercarial shedding levels from Bithynia snails — A preliminary study  

Microsoft Academic Search

Opisthorchis viverrini requires Bithynia snails as the first intermediate host and cyprinid fish as the second intermediate host. Very low natural infection rates have been reported in Bithynia snails, but very high rates have been found in cyprinid fish in the same endemic region. This study investigated the effect of light intensity, the most important stimulus, on the quantity of

Sasithorn Kaewkes; Wanlop Kaewkes; Thidarut Boonmars; Banchob Sripa

297

A molecular phylogeography approach to biological invasions of the New World by parthenogenetic Thiarid snails  

Microsoft Academic Search

The parthenogenetic snail Melanoides tuberculata , present in tropical fresh waters of most of the Old World before 1950, has now invaded the Neotropical area. The phylogeography of this snail was studied to evaluate the pathways and number of such invasions. Because of parthenogenetic reproduction, individuals are structured into genetical clones. Within populations from both the original and invaded areas,

B. FACON; J.-P. POINTIER; M. GLAUBRECHT; C. POUX; P. JARNE; P. DAVID

2003-01-01

298

BOTANICAL EXTRACTS EXHIBIT DUAL ACTION AGAINST CULEX PIPIENS LARVAE AND BIOMPHALARIA ALEXANDRINA SNAILS  

Microsoft Academic Search

Some extracts of Euphorbia helioscopia (Euphorbiaceae), Calendula micrantha (Compositae) and Azadriachta indica (Meliaceae) were screened for the control of Culex pipiens larvae, the vector of Filariasis and Biomphalaria alexandrina snails the vector of Schistosomiasis in Egypt. These plants exhibit dual effect on both pests which share the same aquatic breeding habitat and are of medical importance. B. alexandrina snails were

W. M. ELYASSAKI; M. M. EL-SAYED

299

THE PREFERENCE OF MOLLUSK EATING FISH FOR THREE AQUATIC SNAILS THAT VECTOR FISH TREMATODES.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Melanoides tuberculata, Planorbella trivolvis and Physella heterostropha are three aquatic snails which host trematodes that can infect both cultured and wild populations of fish causing serious problems. These three snail species were offered to black carp Mylopharngodon pisceus, redear sunfish Le...

300

Effects of desiccation on two life stages of an invasive snail and its native cohabitant  

Microsoft Academic Search

Invasive species are of critical concern as they have the potential to rapidly alter biotic systems around the globe. The\\u000a upper Mississippi River (UMR) system has been recently invaded by the aquatic snail, Bithynia tentaculata, which spread from the Great Lakes region. In addition to potentially impacting native aquatic snails, B. tentaculata also carries three parasites which kill thousands of

Allison M. Wood; Cody R. Haro; Roger J. Haro; Gregory J. Sandland

301

Guanine and Inosine Nucleotides, Nucleosides and Oxypurines in Snail Muscles as Potential Biomarkers of Fluoride Toxicity  

Microsoft Academic Search

The aim of the present study was to determine the toxicity of fluorides on energy metabolism in muscles of the Helix aspersa maxima snail. Qualitative and quantitative analysis of purine compounds was performed in slices of foot from mature snails with high-performance liquid chromatography. Fluoride concentrations were measured using an ion-selective electrode and gas chromatography. The results show that exposure

Monika E. Ra?; Krzysztof Safranow; Barbara Do??gowska; Zygmunt Machoy

2007-01-01

302

Acetylation and hydroxylation of sulphatroxazole in the snail Cepaea hortensis and the slug Arion rufus  

Microsoft Academic Search

The snail Cepaea hortensis can acetylate and hydroxylate sulphatroxazole via a pathway similar to that in man. The principal metabolic pathways, in order of decreasing rate, are hydroxylation, glucuronidation and acetylation. The slug Anion rufus also can acetylate and hydroxylate sulphatroxazole, although, in contrast to the snail, is rate of acetylation is higher than that of hydroxylation.

T. B. Vree; M. L. Vree; J. F. M. Nouws

1987-01-01

303

Acetylation and hydroxylation of sulphatroxazole in the snail Cepaea hortensis and the slug Arion rufus.  

PubMed

The snail Cepaea hortensis can acetylate and hydroxylate sulphatroxazole via a pathway similar to that in man. The principal metabolic pathways, in order of decreasing rate, are hydroxylation, glucuronidation and acetylation. The slug Arion rufus also can acetylate and hydroxylate sulphatroxazole, although, in contrast to the snail, is rate of acetylation is higher than that of hydroxylation. PMID:3564322

Vree, T B; Vree, M L; Nouws, J F

1987-01-01

304

Snail/beta-catenin signaling protects breast cancer cells from hypoxia attack  

SciTech Connect

The tolerance of cancer cells to hypoxia depends on the combination of different factors – from increase of glycolysis (Warburg Effect) to activation of intracellular growth/apoptotic pathways. Less is known about the influence of epithelial–mesenchymal transition (EMT) and EMT-associated pathways on the cell sensitivity to hypoxia. The aim of this study was to explore the role of Snail signaling, one of the key EMT pathways, in the mediating of hypoxia response and regulation of cell sensitivity to hypoxia, using as a model in vitro cultured breast cancer cells. Earlier we have shown that estrogen-independent HBL-100 breast cancer cells differ from estrogen-dependent MCF-7 cells with increased expression of Snail1, and demonstrated Snail1 involvement into formation of hormone-resistant phenotype. Because Snail1 belongs to hypoxia-activated proteins, here we studied the influence of Snail1 signaling on the cell tolerance to hypoxia. We found that Snail1-enriched HBL-100 cells were less sensitive to hypoxia-induced growth suppression if compared with MCF-7 line (31% MCF-7 vs. 71% HBL-100 cell viability after 1% O{sub 2} atmosphere for 3 days). Snail1 knock-down enhanced the hypoxia-induced inhibition of cell proliferation giving the direct evidence of Snail1 involvement into cell protection from hypoxia attack. The protective effect of Snail1 was shown to be mediated, at least in a part, via beta-catenin which positively regulated expression of HIF-1-dependent genes. Finally, we found that cell tolerance to hypoxia was accompanied with the failure in the phosphorylation of AMPK – the key energy sensor, and demonstrated an inverse relationship between AMPK and Snail/beta-catenin signaling. Totally, our data show that Snail1 and beta-catenin, besides association with loss of hormone dependence, protect cancer cells from hypoxia and may serve as an important target in the treatment of breast cancer. Moreover, we suggest that the level of these proteins as well the level of AMPK phosphorylation may be considered as predictors of the tumor sensitivity to anti-angiogenic drugs. - Highlights: • Snail1 protects breast cancer cells from hypoxia. • Protective effect of Snail1 is mediated via ?-catenin/HIF-1 pathway. • Snail/?-catenin signaling is negatively controlled by the energy sensor – AMPK. • The failure in AMPK phosphorylation drives cells to the hypoxia-tolerant state.

Scherbakov, Alexander M., E-mail: alex.scherbakov@gmail.com [Laboratory of Clinical Biochemistry, Institute of Clinical Oncology, N.N. Blokhin Cancer Research Centre, Kashirskoye sh. 24, Moscow 115478 (Russian Federation); Stefanova, Lidia B.; Sorokin, Danila V.; Semina, Svetlana E. [Laboratory of Molecular Endocrinology, Institute of Carcinogenesis, N.N. Blokhin Cancer Research Centre, Kashirskoye sh. 24, Moscow 115478 (Russian Federation); Berstein, Lev M. [Laboratory of Oncoendocrinology, N.N. Petrov Research Institute of Oncology, St. Petersburg 197758 (Russian Federation); Krasil’nikov, Mikhail A. [Laboratory of Molecular Endocrinology, Institute of Carcinogenesis, N.N. Blokhin Cancer Research Centre, Kashirskoye sh. 24, Moscow 115478 (Russian Federation)

2013-12-10

305

40 CFR 35.1605-2 - Freshwater lake.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Freshwater lake. 35.1605-2 Section 35.1605-2 Protection...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-2 Freshwater lake. Any inland pond, reservoir,...

2010-07-01

306

40 CFR 35.1605-2 - Freshwater lake.  

...2014-07-01 2014-07-01 false Freshwater lake. 35.1605-2 Section 35.1605-2 Protection...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-2 Freshwater lake. Any inland pond, reservoir,...

2014-07-01

307

40 CFR 35.1605-2 - Freshwater lake.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Freshwater lake. 35.1605-2 Section 35.1605-2 Protection...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-2 Freshwater lake. Any inland pond, reservoir,...

2011-07-01

308

40 CFR 35.1605-2 - Freshwater lake.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Freshwater lake. 35.1605-2 Section 35.1605-2 Protection...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-2 Freshwater lake. Any inland pond, reservoir,...

2013-07-01

309

40 CFR 35.1605-2 - Freshwater lake.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Freshwater lake. 35.1605-2 Section 35.1605-2 Protection...Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-2 Freshwater lake. Any inland pond, reservoir,...

2012-07-01

310

Snail1 controls bone mass by regulating Runx2 and VDR expression during osteoblast differentiation.  

PubMed

Bone undergoes continuous remodelling throughout adult life, and the equilibrium between bone formation by osteoblasts and bone resorption by osteoclasts defines the final bone mass. Here we show that Snail1 regulates this balance by controlling osteoblast differentiation. Snail1 is necessary for the early steps of osteoblast development, and it must be downregulated for their final differentiation. At the molecular level, Snail1 controls bone mass by repressing the transcription of both the osteoblast differentiation factor Runx2 and the vitamin D receptor (VDR) genes in osteoblasts. Sustained activation of Snail1 in transgenic mice provokes deficient osteoblast differentiation, which, together with the loss of vitamin D signalling in the bone, also impairs osteoclastogenesis. Indeed, the mineralisation of the bone matrix is severely affected, leading to hypocalcemia-independent osteomalacia. Our data show that the impact of Snail1 activity on the osteoblast population regulates the course of bone cells differentiation and ensures normal bone remodelling. PMID:19197242

de Frutos, Cristina A; Dacquin, Romain; Vega, Sonia; Jurdic, Pierre; Machuca-Gayet, Irma; Nieto, M Angela

2009-03-18

311

Transcription factor Snail regulates TNF-?-mediated synovial fibroblast activation in rheumatoid joint.  

PubMed

Objective. Transcription factor Snail is involved in various biological functions. We hypothesized that this molecule regulates TNF-?-mediated synovial fibroblasts (SF) activation in rheumatoid joint, and examined its roles in expression of Cadherin-11 (Cad-11) and myofibroblast markers, invasive ability and IL-6 production. Methods. Synovium was obtained from rheumatoid arthritis (RA) patients and collagen-induced arthritis (CIA) rats. SF were treated with TNF-? or a Wnt signaling inducer, and CIA joints were injected with a TNF-? antagonist. Modulation of Snail expression in SF and joints was performed by lentiviral vector-mediated transfer of cDNA or short hairpin RNA. Results. Snail and Cad-11 were expressed at higher levels in synovium and SF from RA patients and CIA rats. TNF-? stimulation or Wnt signaling activation upregulated the expression levels of Snail, Cad-11 and ?-smooth muscle actin (SMA) in SF, and anti-TNF-? therapy down-regulated their expression levels in CIA joints. While Snail-overexpressed SF transfectants had increased expression levels of Cad-11 and ?-SMA and enhanced TNF-?-mediated invasive capacity and IL-6 production, Snail-knockdowned CIASF transfectants had decreased expression levels and the opposite effect on these functions. Snail-overexpressed normal joints had hyperplastic synovium with increased expression levels of Cad-11, ?-SMA and IL-6. Silencing Snail expression ameliorated arthritis with reduced Cad-11 expression and extracellular matrix deposition levels in CIA joints, whereas overexpression of Snail exacerbated arthritis with increased expression and deposition levels. Conclusion. Our results demonstrate that Snail regulates TNF-?-mediated SF activation in rheumatoid joint, and these findings might contribute to the pharmacological development of therapeutics targeting SF in RA patients. © 2014 American College of Rheumatology. PMID:25303734

Chen, Shih-Yao; Shiau, Ai-Li; Li, Yuan-Tsung; Lin, Chi-Chen; Jou, I-Ming; Liu, Ming-Fei; Wu, Chao-Liang; Wang, Chrong-Reen

2014-10-01

312

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

313

Population studies on Oncomelania quadrasi, the snail intermediate host of Schistosoma japonicum, in the Philippines. 5. Quantitative analysis on successful snail control by land reclamation.  

PubMed

For the control of Oncomelania quadrasi, environmental modifications, i.e., clearing of vegetation, leveling of swampy depression and draining of stagnant water by channeling and excavation were carried out at 3 areas in Leyte, Philippines from 1974 to 1977. The change of snail population resulted in the land reclamation was evaluated by the methods previously developed by the population studies on this snail. As a result of statistical analysis based on y = log(x + 0.01) transformation and the antilogarithmic mean density A-y = (antilog -y) -0.01, the reduction of snail population was observed at 13 out of 18 sites studied at 3 project areas and the significant reduction was statistically confirmed at 9 sites of them. Particularly at Dagami area, which was a wide and heavily snail-infested land adjacent to Dagami Poblacion, the reduction rate of snail density reached 87.7% to 99.2% and some wet depressions have been converted into good rice fields with little snail infestation at the last survey. PMID:3090317

Makiya, K; Tanaka, H; Bañez, E; Blas, B L; Santos, A T

1986-04-01

314

Observations on the distribution of freshwater mollusca and chemistry of the natural waters in the south-eastern Transvaal and adjacent northern Swaziland*  

PubMed Central

An extensive survey of the molluscan fauna and of the chemistry of the freshwaters of the Eastern Transvaal Lowveld has revealed no simple correlation between the two. The waters fall into four fairly distinct and geographically associated groups chiefly characterized by their calcium and magnesium content. The frequency of the two intermediate hosts of bilharziasis was found to be roughly proportional to the hardness of the water but as the latter, in this area, is associated with altitude and this again with temperature and stream gradient it is thought highly probable that the distribution of these snails is the result of the interaction of a complex of factors. None of the individual chemical constituents in any of the waters examined is regarded as outside the tolerance range of these snails. It is also concluded that under natural conditions this area would have had few waterbodies suitable for colonization by these snails but that the expansion of irrigation schemes has created ideal conditions for their rapid establishment throughout the area. PMID:14163962

Schutte, C. H. J.; Frank, G. H.

1964-01-01

315

[Equipment for biological experiments with snails aboard piloted orbital stations].  

PubMed

To fly biological experiments aboard piloted orbital stations, research equipment was built up of an incubation container, filter system and automatic temperature controller. Investigations included analysis of the makeup and concentrations of gases produced by animals (snails) during biocycle, and emitted after death. Filters are chemisorption active fibrous materials (AFM) with high sorption rate and water receptivity (cation exchange fiber VION-KN-1 and anion exchange fiber VION-AS-1), and water-repellent carbon adsorbent SKLTS. AFM filters were effective in air cleaning and practically excluded ingress of chemical substances from the container into cabin atmosphere over more than 100 days. PMID:21033402

Gorgiladze, G I; Korotkova, E V; Kuznetsova, E E; Mukhamedieva, L N; Begrov, V V; Pepeliaev, Iu V

2010-01-01

316

Toxic effects of Cadmium on the garden snail (Helix aspersa)  

SciTech Connect

Spreading treated municipal wastes on agricultural and forest lands is becoming an established method of disposal. However, there is concern about the deleterious effects of toxicants, particularly cadmium, in the sludges. Cadmium concentrations in sewage sludge have been reported as high as 1500 ppM. The work reported here is a part of a larger project to investigate the ecological effects of municipal wastes on forest lands. Snails, Helix aspersa, were chosen to examine the entrance of cadmium into terrestrial food chains. This experiment was designed to determine cadmium accumulation, acute toxicity, and behavioral, reproductive and growth responses with increasing levels of cadmium.

Russell, L.K. (Northrop Services Inc., Corvallis, OR); DeHaven, J.I.; Botts, R.P.

1981-05-01

317

Davis Pond Freshwater Prediversion Biomonitoring Study: Freshwater Fisheries and Eagles  

USGS Publications Warehouse

In January 2001, the construction of the Davis Pond freshwater diversion structure was completed by the U.S. Army Corps of Engineers. The diversion of freshwater from the Mississippi River is intended to mitigate saltwater intrusion from the Gulf of Mexico and to lessen the concomitant loss of wetland areas. In addition to the freshwater inflow, Barataria Bay basin would receive nutrients, increased flows of sediments, and water-borne and sediment-bound compounds. The purpose of this biomonitoring study was, therefore, to serve as a baseline for prediversion concentrations of selected contaminants in bald eagle (Haliaeetus leucocephalus) nestlings (hereafter referred to as eaglets), representative freshwater fish, and bivalves. Samples were collected from January through June 2001. Two similarly designed postdiversion studies, as described in the biological monitoring program, are planned. Active bald eagle nests targeted for sampling eaglet blood (n = 6) were generally located southwest and south of the diversion structure. The designated sites for aquatic animal sampling were at Lake Salvador, at Lake Cataouatche, at Bayou Couba, and along the Mississippi River. Aquatic animals representative of eagle prey were collected. Fish were from three different trophic levels and have varying feeding strategies and life histories. These included herbivorous striped mullet (Mugil cephalus), omnivorous blue catfish (Ictalurus furcatus), and carnivorous largemouth bass (Micropterus salmoides). Three individuals per species were collected at each of the four sampling sites. Freshwater Atlantic rangia clams (Rangia cuneata) were collected at the downstream marsh sites, and zebra mussels (Dreissena spp.) were collected on the Mississippi River. The U.S. Geological Survey (USGS) Biomonitoring of Environmental Status and Trends (BEST) protocols served as guides for fish sampling and health assessments. Fish are useful for monitoring aquatic ecosystems because they accumulate pesticides and other contaminants. Biomarker data on individual fish, generated at the USGS National Wetlands Research Center (Lafayette, La.), included percent white blood cells in whole blood, spleen weight to body weight ratio, liver weight to body weight ratio, condition factor, splenic macrophage aggregates, and liver microsomal 7-ethoxyresorufin-o-deethylase (EROD) activity. Fish age was estimated by comparing total lengths with values from the same species in the Southeast United States as determined from the literature. Contaminant analyses were coordinated by the U.S. Fish and Wildlife Service (USFWS) Analytical Control Facility (Laurel, Md.), where residues of organochlorine (OC) pesticides, total polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons (AHs), and trace elements were determined. The organic contaminant data were generated at the Mississippi State University Chemical Lab (Mississippi State, Miss.), and the inorganic contaminant data were generated by the Texas A&M University Geochemical and Environmental Research Group (College Station, Tex.). Statistical tests were performed to assess relationships among contaminants, fish age, fish species, and collection sites.

Jenkins, Jill A.; Bourgeois, E. Beth; Jeske, Clint W.

2008-01-01

318

Freshwater Ecoregions of the World: A New Map of Biogeographic Units for Freshwater Biodiversity Conservation  

NSDL National Science Digital Library

We present a new map depicting the first global biogeographic regionalization of Earth's freshwater systems. This map of freshwater ecoregions is based on the distributions and compositions of freshwater fish species and incorporates major ecological and evolutionary patterns. Covering virtually all freshwater habitats on Earth, this ecoregion map, together with associated species data, is a useful tool for underpinning global and regional conservation planning efforts (particularly to identify outstanding and imperiled freshwater systems); for serving as a logical framework for large-scale conservation strategies; and for providing a global-scale knowledge base for increasing freshwater biogeographic literacy. Preliminary data for fish species compiled by ecoregion reveal some previously unrecognized areas of high biodiversity, highlighting the benefit of looking at the world's freshwaters through a new framework.

Robin Abell et al (WWF;)

2008-05-01

319

Reclaiming freshwater sustainability in the Cadillac Desert  

E-print Network

the plow." Early stewards of freshwater resources--like John Wesley Powell-- warned that the American WestReclaiming freshwater sustainability in the Cadillac Desert John L. Saboa,1 , Tushar Sinhaa,2 , Laura C. Bowlingb , Gerrit H. W. Schoupsc , Wesley W. Wallenderd,e , Michael E. Campanaf , Keith A

Sinha, Tushar

320

Overexpression of Snail is associated with lymph node metastasis and poor prognosis in patients with gastric cancer  

PubMed Central

Background Epithelial–mesenchymal transition (EMT) plays a significant role in tumor progression and invasion. Snail is a known regulator of EMT in various malignant tumors. This study investigated the role of Snail in gastric cancer. Methods We examined the effects of silenced or overexpressed Snail using lenti-viral constructs in gastric cancer cells. Immunohistochemical analysis of tissue microarrays from 314 patients with gastric adenocarcinoma (GC) was used to determine Snail’s clinicopathological and prognostic significance. Differential gene expression in 45 GC specimens with Snail overexpression was investigated using cDNA microarray analysis. Results Silencing of Snail by shRNA decreased invasion and migration in GC cell lines. Conversely, Snail overexpression increased invasion and migration of gastric cancer cells, in line with increased VEGF and MMP11. Snail overexpression (?75% positive nuclear staining) was also significantly associated with tumor progression (P?Snail overexpression, including genes related to metastasis and invasion. Conclusion Snail significantly affects invasiveness/migratory ability of GCs, and may also be used as a predictive biomarker for prognosis or aggressiveness of GCs. PMID:23151184

2012-01-01

321

CCR7 pathway induces epithelial-mesenchymal transition through up-regulation of Snail signaling in gastric cancer.  

PubMed

The chemokine receptor 7 (CCR7) and Snail signaling have been linked to various types of cancers. The associations between these signalings and the epithelial-mesenchymal transition (EMT) are not clear in gastric cancer. Here, the expression of CCR7 and Snail was detected in gastric cancer by immunohistochemistry and Western blot. Meanwhile, gastric cancer cells were subjected to CCL19, si-control, and si-Snail treatment. Cell cycle, migration, and invasion were also analyzed. The expression patterns of CCR7 and Snail were similar in either gastric cancer tissues or cells. The increased expression of CCR7 was closely associated with the increased Snail expression, which both were closely correlated with metastasis, stage and differentiation, and poor prognosis. The increased p-ERK, p-AKT, Snail, and MMP9 expression and the decreased E-cadherin were confirmed in MGC803 cells in a dose-dependent manner in response to CCL19 treatment. However, the blockade of Snail abrogated the up-regulation of MMP9 and down-regulation of E-cadherin. CCR7-induced ERK and PI3K pathway regulated Snail signaling. Besides si-Snail treatment led to MGC803 cell cycle arrest and affected the migration and invasion. In conclusion, our study suggested that CCR7 promotes Snail expression to induce the EMT, resulting in cell cycle progression, migration, and invasion in gastric cancer. CCR7-Snail pathway provided more potential regimens for cancer therapy. PMID:25572817

Zhang, Jianping; Zhou, Yunzhe; Yang, Yonggang

2015-02-01

322

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

E-print Network

(=Planorbella) trivolvis (Say, 1817), Melanoides tuberculata (Müller, 1774), Neritina punctulata Lamarck, 1816 and H. trivolvis are established on Dominica, West Indies. We tested a limited number of M. tuberculata

Dillon, Robert T.

323

Developmental Consequences of Egg Capsule Attributes among Sibling and Nonsibling Egg Capsules of the Freshwater Snail Lymnaea columella  

Microsoft Academic Search

Among invertebrate species, female reproductive energy can be divided two ways, the production of many small eggs each with small amounts of energy or a few large eggs each with large amounts of energy (McEdward, 1988; Baur, 1994; Baur & Baur, 1997). It has also been demonstrated that variation in egg size and energy content among species leads to variation

Keller Kristin

2002-01-01

324

Snail Regulates Cell-Matrix Adhesion by Regulation of the Expression of Integrins and Basement Membrane Proteins*  

PubMed Central

Snail, a transcriptional repressor of E-cadherin expression, plays a role in the process of epithelial-mesenchymal transition. However, the molecular basis of the role of snail in epithelial-mesenchymal transition has not been fully clarified. Here we show that the expression of snail in epithelial Madin-Darby canine kidney (MDCK) and A431 cells enhances both cell detachment and attachment. Snail did not confer resistance to anoikis induced by loss of contact but instead enhanced cell attachment to extracellular matrices such as fibronectin. This attachment was inhibited by Arg-Gly-Asp (RGD) peptides. Up-regulation of the promoter activity of integrin ?V was observed in snail-expressing MDCK (MDCK/snail) cells. Snail also enhanced MDCK cell migration toward osteopontin that is a ligand for integrin ?V?3. We confirmed the reduction of basement membrane proteins such as laminin (LN) ?3, ?3, and ?2 (laminin-5/LN-5) and of receptors for LN-5 such as integrins ?3, ?6, or ?4 in MDCK/snail or in snail-expressing A431 (A431/snail) cells. Nevertheless, suppression of LN-?3 chain by transient transfection of small interference RNAs resulted in no enhancement of cell detachment. We also found an induction of matrix metalloproteinase-3 in MDCK/snail and A431/snail cells. However, the inhibition of matrix metalloproteinase-3 showed no significant effect on the detachment of MDCK/snail cells. These results suggest that snail enhances cell detachment by multiple mechanism and leads to cell migration and reattachment at a second site, at least in part, by changing the expression of integrins in the cells. PMID:18593711

Haraguchi, Misako; Okubo, Tadashi; Miyashita, Yayoi; Miyamoto, Yasunori; Hayashi, Masao; Crotti, Tania N.; McHugh, Kevin P.; Ozawa, Masayuki

2008-01-01

325

Allying with armored snails: the complete genome of gammaproteobacterial endosymbiont.  

PubMed

Deep-sea vents harbor dense populations of various animals that have their specific symbiotic bacteria. Scaly-foot gastropods, which are snails with mineralized scales covering the sides of its foot, have a gammaproteobacterial endosymbiont in their enlarged esophageal glands and diverse epibionts on the surface of their scales. In this study, we report the complete genome sequencing of gammaproteobacterial endosymbiont. The endosymbiont genome displays features consistent with ongoing genome reduction such as large proportions of pseudogenes and insertion elements. The genome encodes functions commonly found in deep-sea vent chemoautotrophs such as sulfur oxidation and carbon fixation. Stable carbon isotope ((13)C)-labeling experiments confirmed the endosymbiont chemoautotrophy. The genome also includes an intact hydrogenase gene cluster that potentially has been horizontally transferred from phylogenetically distant bacteria. Notable findings include the presence and transcription of genes for flagellar assembly, through which proteins are potentially exported from bacterium to the host. Symbionts of snail individuals exhibited extreme genetic homogeneity, showing only two synonymous changes in 19 different genes (13?810 positions in total) determined for 32 individual gastropods collected from a single colony at one time. The extremely low genetic individuality in endosymbionts probably reflects that the stringent symbiont selection by host prevents the random genetic drift in the small population of horizontally transmitted symbiont. This study is the first complete genome analysis of gastropod endosymbiont and offers an opportunity to study genome evolution in a recently evolved endosymbiont. PMID:23924784

Nakagawa, Satoshi; Shimamura, Shigeru; Takaki, Yoshihiro; Suzuki, Yohey; Murakami, Shun-ichi; Watanabe, Tamaki; Fujiyoshi, So; Mino, Sayaka; Sawabe, Tomoo; Maeda, Takahiro; Makita, Hiroko; Nemoto, Suguru; Nishimura, Shin-Ichiro; Watanabe, Hiromi; Watsuji, Tomo-o; Takai, Ken

2014-01-01

326

Allying with armored snails: the complete genome of gammaproteobacterial endosymbiont  

PubMed Central

Deep-sea vents harbor dense populations of various animals that have their specific symbiotic bacteria. Scaly-foot gastropods, which are snails with mineralized scales covering the sides of its foot, have a gammaproteobacterial endosymbiont in their enlarged esophageal glands and diverse epibionts on the surface of their scales. In this study, we report the complete genome sequencing of gammaproteobacterial endosymbiont. The endosymbiont genome displays features consistent with ongoing genome reduction such as large proportions of pseudogenes and insertion elements. The genome encodes functions commonly found in deep-sea vent chemoautotrophs such as sulfur oxidation and carbon fixation. Stable carbon isotope (13C)-labeling experiments confirmed the endosymbiont chemoautotrophy. The genome also includes an intact hydrogenase gene cluster that potentially has been horizontally transferred from phylogenetically distant bacteria. Notable findings include the presence and transcription of genes for flagellar assembly, through which proteins are potentially exported from bacterium to the host. Symbionts of snail individuals exhibited extreme genetic homogeneity, showing only two synonymous changes in 19 different genes (13?810 positions in total) determined for 32 individual gastropods collected from a single colony at one time. The extremely low genetic individuality in endosymbionts probably reflects that the stringent symbiont selection by host prevents the random genetic drift in the small population of horizontally transmitted symbiont. This study is the first complete genome analysis of gastropod endosymbiont and offers an opportunity to study genome evolution in a recently evolved endosymbiont. PMID:23924784

Nakagawa, Satoshi; Shimamura, Shigeru; Takaki, Yoshihiro; Suzuki, Yohey; Murakami, Shun-ichi; Watanabe, Tamaki; Fujiyoshi, So; Mino, Sayaka; Sawabe, Tomoo; Maeda, Takahiro; Makita, Hiroko; Nemoto, Suguru; Nishimura, Shin-Ichiro; Watanabe, Hiromi; Watsuji, Tomo-o; Takai, Ken

2014-01-01

327

A molecular role for lysyl oxidase-like 2 enzyme in Snail regulation and tumor progression  

PubMed Central

The transcription factor Snail controls epithelial–mesenchymal transitions (EMT) by repressing E-cadherin expression and other epithelial genes. However, the mechanisms involved in the regulation of Snail function are not fully understood. Here we show that lysyl-oxidase-like 2 and 3 (LOXL2 and LOXL3), two members of the lysyl-oxidase gene family, interact and cooperate with Snail to downregulate E-cadherin expression. Snail's lysine residues 98 and 137 are essential for Snail stability, functional cooperation with LOXL2/3 and induction of EMT. Overexpression of LOXL2 or LOXL3 in epithelial cells induces an EMT process, supporting their implication in tumor progression. The biological importance of LOXL2 is further supported by RNA interference of LOXL2 in Snail-expressing metastatic carcinoma cells, which led to a strong decrease of tumor growth associated to increased apoptosis and reduced expression of mesenchymal and invasive/angiogenic markers. Taken together, these results establish a direct link between LOXL2 and Snail in carcinoma progression. PMID:16096638

Peinado, Héctor; del Carmen Iglesias-de la Cruz, Maria; Olmeda, David; Csiszar, Katalin; Fong, Keith S K; Vega, Sonia; Nieto, Maria Angela; Cano, Amparo; Portillo, Francisco

2005-01-01

328

Snail-Mediated Regulation of Reactive Oxygen Species in ARCaP Human Prostate Cancer Cells  

PubMed Central

Reactive oxygen species increases in various diseases including cancer and has been associated with induction of epithelial-mesenchymal transition (EMT), as evidenced by decrease in cell adhesion-associated molecules like E-cadherin, and increase in mesenchymal markers like vimentin. We investigated the molecular mechanisms by which Snail transcription factor, an inducer of EMT, promotes tumor aggressiveness utilizing ARCaP prostate cancer cell line. An EMT model created by Snail overexpression in ARCaP cells was associated with decreased E-cadherin and increased vimentin. Moreover, Snail-expressing cells displayed increased concentration of reactive oxygen species (ROS), specifically, superoxide and hydrogen peroxide, in vitro and in vivo. Real time PCR profiling demonstrated increased expression of oxidative stress-responsive genes, such as aldeyhyde oxidase I, in response to Snail. The ROS scavenger, N-acetyl cysteine partially reversed Snail-mediated EMT after 7 days characterized by increased E-cadherin levels and decreased ERK activity, while treatment with the MEK inhibitor, UO126, resulted in a more marked effect by 3 days, characterized by cells returning back to the epithelial morphology and increased E-cadherin. In conclusion, this study shows for the first time that Snail transcription factor can regulate oxidative stress enzymes and increase ROS-mediated EMT regulated in part by ERK activation. Therefore, Snail may be an attractive molecule for therapeutic targeting to prevent tumor progression in human prostate cancer. PMID:21093414

Barnett, Petrina; Arnold, Rebecca S.; Mezencev, Roman; Chung, Leland W. K.; Zayzafoon, Majd; Odero-Marah, Valerie

2010-01-01

329

Snail intermediate host/Schistosoma haematobium relationships from three transmission sites in Benin (West Africa).  

PubMed

The relationships between three strains of Schistosoma haematobium (Doh, Sô-Tchanhoué and Toho-Todougba; from Benin, West Africa) and their snail hosts were assessed by measurement of several life-history traits, including the infection rate; pre-patent period; cercarial production of each parasite strain; and growth, fecundity and survival of the host snails. Adaptations to its local snail host was found for the Toho-Todougba strain and included a short pre-patent period, a long patent period and production of more cercariae in its local snail host. In contrast, the life-history traits of the Doh and Sô-Tchanhoué strains indicated non-local adaptations, as some sympatric host-parasite combinations were not compatible, the highest infection rates occurred in the allopatric snail Bulinus wrighti, and the duration of cercarial production was short because of the high level of mortality of the snails. Furthermore, snail reproduction ceased following infection by each of the three parasite strains, and the life-history traits were not influenced by the miracidial dose. PMID:23052762

Ibikounlé, Moudachirou; Mouahid, Gabriel; Mintsa Nguema, Rodrigue; Sakiti, Nestor; Massougbodji, Achille; Moné, Hélène

2013-01-01

330

Temperature dependence of Opisthorchis viverrini infection in first intermediate host snail, Bithynia siamensis goniomphalos.  

PubMed

Determining of the success of a parasite's infectiveness in its snail host clearly depends on environmental conditions. Temperature, one of the most influential factors impinging on metabolism of cold-blooded animals, is believed to be an important factor in parasitic infection in snails. In order to elucidate the influence of temperature, sex and size of snails on infectivity of Opisthorchis viverrini to its first intermediate host, Bithynia siamensis goniomphalos, 960 snails were divided into 2 groups by sex. Each group was subdivided by their size into small and medium sub-groups. Each snail was fed with embryonated uterine-eggs of O. viverrini at different temperatures (16-37°C, 3°C intervals). Dissections were carried out 1, 7, 14, 28 and 56 days thereafter and detection of O. viverrini infection was undertaken by PCR using specific primers. Infection was strongly temperature-dependent, as temperature increases of 1°C resulted in increased odds of infection 5.4% (P<0.01). A temperature of 34°C gave the highest rate of infection of 44.14%. We also found that the odds of infection in small sized snails was 39.8% higher relative to medium sized snails (P<0.05). Relative to day 1, the decrease in the odds of infection was detected when the day post infection was longer (P<0.01). Proportion of infection in female was not different to male significantly. PMID:24161535

Prasopdee, Sattrachai; Kulsantiwong, Jutharat; Piratae, Supawadee; Khampoosa, Panita; Thammasiri, Chalida; Suwannatrai, Apiporn; Laha, Thewarach; Grams, Rudi; Loukas, Alex; Tesana, Smarn

2015-01-01

331

Common Freshwater Fish Parasites Pictorial Guide: Digenean Trematodes1  

E-print Network

FA-112 Common Freshwater Fish Parasites Pictorial Guide: Digenean Trematodes1 Deborah B. Pouder parasites. The publications included in this series are: · Common Freshwater Fish Parasites Pictorial Guide: Sessile Ciliates · Common Freshwater Fish Parasites Pictorial Guide: Motile Ciliates · Common Freshwater

Watson, Craig A.

332

Common Freshwater Fish Parasites Pictorial Guide: Flagellates1  

E-print Network

FA-109 Common Freshwater Fish Parasites Pictorial Guide: Flagellates1 Deborah B. Pouder, Eric W parasites. The publications included in this series are: · Common Freshwater Fish Parasites Pictorial Guide: Sessile Ciliates · Common Freshwater Fish Parasites Pictorial Guide: Motile Ciliates · Common Freshwater

Watson, Craig A.

333

Common Freshwater Fish Parasites Pictorial Guide: Dinoflagellates, Coccidia, Microsporidians, &  

E-print Network

FA-110 Common Freshwater Fish Parasites Pictorial Guide: Dinoflagellates, Coccidia, Microsporidians in the identification of common freshwater fish parasites. The publications included in this series are: · Common Freshwater Fish Parasites Pictorial Guide: Sessile Ciliates · Common Freshwater Fish Parasites Pictorial

Watson, Craig A.

334

The mesoscale and regional freshwater flux  

NASA Astrophysics Data System (ADS)

The closer we look at the ocean, with improved instrumentation and models, the less it looks like the familiar 'textbook' view of overly smoothed maps of SST and SSS, with ocean scale circulation gyres, and more of a jumble of a westward parade of mesoscale features. The question arises: what role does the mesoscale play in compensating the air-sea flux of heat and freshwater? Here we focus on the freshwater balance within the salty North Atlantic subtropics regime, where the annual evaporation minus precipitation (E-P) is over 1 m/year. A traditional view is that the required quasi-steady state ocean freshwater inflow is derived from the wind-driven circulation and the associated shallow meridional overturning circulation. Here we evaluate if the mesoscale 'eddy' field, may stir into the subtropical regime a significant share of the needed freshwater. The Voluntary Observing Ships (VOS) data provide an overview of the SSS seasonal cycle of the Atlantic subtropical regime. While E-P is always positive, greater in January-July, minimum in October, the SSS displays a maximum in October, minimum occurs in April. It is hypothesized that the lower SSS of the winter/spring period marks increased winter freshwater flux by meso-scale activity. While the eddy freshwater flux can be estimated from the Rapid thermohaline and velocity data sections near 24.5°N, it is the meridional convergence of the eddy freshwater flux that compensates the regional E-P. We use the SODA output, which assimilates the VOS and Rapid data, to estimate the eddy freshwater flux convergence. Our preliminary assessment is that the eddy flux convergence does play a major role in closing the seasonal freshwater cycle of the North Atlantic surface layer.

Gordon, A. L.; Giulivi, C. F.

2012-12-01

335

Suppression of SCARA5 by Snail1 is essential for EMT-associated cell migration of A549 cells  

PubMed Central

Accumulating evidence indicates that epithelial-to-mesenchymal transition (EMT) might be a key event for cancer progression. The upregulation of Snail1, one of the most extensively studied EMT regulators, has been implicated in cancer metastasis, but the underlying mechanisms remain unclear. This study aims to identify that Snail1 targets regulating EMT-associated cancer cell migration. Human lung carcinoma A549 cells were treated with transforming growth factor beta 1 (TGF-?1), and EMT-associated phenotypic and functional alterations were monitored. TGF-?1 induced typical EMT-like morphological changes, ‘cadherin switching' and cell migration in A549 cells. TGF-?1 stimulation induced rapid and persistent upregulation of Snail1. Moreover, Snail1 upregulation was required for EMT-associated cell migration. Several metastasis suppressors with putative Snail1-binding sites in their promoters were dramatically repressed in A549 cells during TGF-?1-induced EMT. Gain- and loss-of Snail1 function experiments demonstrated that scavenger receptor class A member 5 (SCARA5) was negatively regulated by Snail1. Importantly, SCARA5 downregulation was essential for EMT-induced migration in A549 cells. The chromatin immunoprecipitation assay revealed that Snail1 could bind to the E-box elements in SCARA5 promoter, implying that SCARA5 is a direct Snail1 target modulating cancer cell mobility during EMT. In addition, we showed that DNA methyltransferase 1 was physically associated with Snail1 to silence SCARA5 expression with an unidentified DNA methylation-independent mechanism, suggesting the complexity of Snail1-mediated epigenetic regulation. Collectively, our data demonstrated that EMT-regulator Snail1 suppresses the expression of SCARA5 to promote cancer progression, highlighting the possibility to target Snail1 and SCARA5 for cancer treatment. PMID:24061576

Liu, J; Hu, G; Chen, D; Gong, A-Y; Soori, G S; Dobleman, T J; Chen, X-M

2013-01-01

336

Influence of water hardness and sulfate on the acute toxicity of chloride to sensitive freshwater invertebrates.  

PubMed

Total dissolved solids (TDS) represent the sum of all common ions (e.g., Na, K, Ca, Mg, chloride, sulfate, and bicarbonate) in freshwater. Currently, no federal water quality criteria exist for the protection of aquatic life for TDS, but because the constituents that constitute TDS are variable, the development of aquatic life criteria for specific ions is more practical than development of aquatic life criteria for TDS. Chloride is one such ion for which aquatic life criteria exist; however, the current aquatic life criteria dataset for chloride is more than 20 years old. Therefore, additional toxicity tests were conducted in the current study to confirm the acute toxicity of chloride to several potentially sensitive invertebrates: water flea (Ceriodaphnia dubia), fingernail clams (Sphaerium simile and Musculium transversum), snail (Gyraulus parvus), and worm (Tubifex tubifex), and determine the extent to which hardness and sulfate modify chloride toxicity. The results indicated a significant ameliorating effect of water hardness (calcium and magnesium) on chloride toxicity for all species tested except the snail; for example, the 48-h chloride median lethal concentration (LC50) for C. dubia at 50?mg/L hardness (977?mg Cl(-) /L) was half that at 800?mg/L hardness (1,836?mg Cl(-) /L). Conversely, sulfate over the range of 25 to 600?mg/L exerted a negligible effect on chloride toxicity to C. dubia. Rank order of LC50 values for chloride at a given water hardness was in the order (lowest to highest): S. simile?

Soucek, David J; Linton, Tyler K; Tarr, Christopher D; Dickinson, Amy; Wickramanayake, Nilesh; Delos, Charles G; Cruz, Luis A

2011-04-01

337

High temperature enhances host pathology in a snail trematode system: possible consequences of climate  

E-print Network

of amphibian limb malformations, and its snail intermediate host Planorbella trivolvis. We determined deformities, phenological mismatch, Planorbella trivolvis, Ribeiroia ondatrae, vital rates Introduction is amplified at higher temperatures. 4. The timing of interactions between R. ondatrae and P. trivolvis may

Johnson, Pieter

338

The production of mammalian trematode infective stages by the snail Galba truncatula.  

PubMed

Several experiments on the breeding of trematode-infected Galba truncatula for obtaining and packaging Fasciola hepatica and Paramphistomum daubneyi metacercariae were carried out to determine the more convenient methods to use for commercial production of these infective stages. Compared to the breeding of infected snails in aquaterraria, the use of 14-cm Petri dishes allowed a greater prevalence of snail infection and a higher number of metacercariae. The production of these larvae was still 2.3-3.4 times greater if infected snails were dissected during the patent period. The aspiration of these metacercariae at the extremity of a Pasteur pipette significantly shortens the time necessary for their transfer from Petri dishes to Eppendorf tubes. Using 14-cm Petri dishes, snail dissection and metacercarial aspiration for their transfer strongly reduce the cost price for metacercarial production of the trematodes Fasciola hepatica and Paramphistomum daubneyi. PMID:23182081

Rondelaud, D; Mouzet, R; Vignoles, P; Dreyfuss, G; Cabaret, J

2014-03-01

339

Bioluminescent signals spatially amplified by wavelength-specific diffusion through the shell of a marine snail  

PubMed Central

Some living organisms produce visible light (bioluminescence) for intra- or interspecific visual communication. Here, we describe a remarkable bioluminescent adaptation in the marine snail Hinea brasiliana. This species produces a luminous display in response to mechanical stimulation caused by encounters with other motile organisms. The light is produced from discrete areas on the snail's body beneath the snail's shell, and must thus overcome this structural barrier to be viewed by an external receiver. The diffusion and transmission efficiency of the shell is greater than a commercial diffuser reference material. Most strikingly, the shell, although opaque and pigmented, selectively diffuses the blue-green wavelength of the species bioluminescence. This diffusion generates a luminous display that is enlarged relative to the original light source. This unusual shell thus allows spatially amplified outward transmission of light communication signals from the snail, while allowing the animal to remain safely inside its hard protective shell. PMID:21159673

Deheyn, Dimitri D.; Wilson, Nerida G.

2011-01-01

340

Dynamic Chromatin Modification Sustains Epithelial-Mesenchymal Transition following Inducible Expression of Snail-1  

PubMed Central

SUMMARY Epithelial-mesenchymal transition (EMT) is thought to contribute to cancer metastasis, but its underlying mechanisms are not well understood. To define early steps in this cellular transformation, we analyzed human mammary epithelial cells with tightly regulated expression of Snail-1, a master regulator of EMT. After Snail-1 induction, epithelial markers were repressed within 6 hr, and mesenchymal genes were induced at 24 hr. Snail-1 binding to its target promoters was transient (6–48 hr) despite continued protein expression, and it was followed by both transient and long-lasting chromatin changes. Pharmacological inhibition of selected histone acetylation and demethylation pathways suppressed the induction as well as the maintenance of Snail-1-mediated EMT. Thus, EMT involves an epigenetic switch that may be prevented or reversed with the use of small-molecule inhibitors of chromatin modifiers. PMID:24360956

Javaid, Sarah; Zhang, Jianmin; Anderssen, Endre; Black, Josh C.; Wittner, Ben S.; Tajima, Ken; Ting, David T.; Smolen, Gromoslaw A.; Zubrowski, Matthew; Desai, Rushil; Maheswaran, Shyamala; Ramaswamy, Sridhar; Whetstine, Johnathan R.; Haber, Daniel A.

2014-01-01

341

Cloning of an olfactory sensory neuron-specific protein in the land snail (Eobania vermiculata).  

PubMed Central

We have isolated a gene encoding for an olfactory sensory neuron (OSN)-specific protein in an invertebrate, the land snail Eobania vermiculata (GenBank accession number AY147909). Using in situ hybridization, we detected expression of its mRNA in the dendrite, cell body and axon of OSNs. By neural tracing, using the lipophilic tracer DiI and in situ hybridization, we have revealed the organization of OSNs and their connections with olfactory glomeruli in the land snail. Sequence and expression pattern analogy of land snail protein with olfactory marker protein (OMP) from vertebrates suggest that the land snail protein is an OMP-like protein. This protein could represent a plesiomorphic character in the evolution of olfactory proteins. PMID:15101416

Mazzatenta, Andrea; Pelosi, Paolo; Cellerino, Alessandro

2004-01-01

342

Stages of oogenesis in the snail, Helix aspersa : cytological, cytochemical and ultrastructural studies  

E-print Network

Stages of oogenesis in the snail, Helix aspersa : cytological, cytochemical and ultrastructural, France. Summary. Oogenesis was studied in adult Helix aspersa using light and electron micros- copy rela- tions between oocytes and follicle cells. Introduction. Oogenesis inside molluscs

Paris-Sud XI, Université de

343

Wet Adhesion and Adhesive Locomotion of Snails on Anti-Adhesive Non-Wetting Surfaces  

PubMed Central

Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted), texture (smooth, rough or granular) or wetting property (hydrophilic or hydrophobic) via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces. PMID:22693563

Shirtcliffe, Neil J.; McHale, Glen; Newton, Michael I.

2012-01-01

344

Evening roosts of the snail kite in Florida  

USGS Publications Warehouse

A total of 36 roost sites of the Snail Kite (Rostrhamus sociabilis) were studied in southern Florida, of which four (11%) were used regularly for 6 or more years. Major roosts were also used as nesting sites. All roosts were in flooded marshes and 33 (91.6%) were in stands of coastal-plain willow. Population increase and the number of roosts were strongly correlated. The number of kites arriving at roosts before sunset was smaller than arriving after sunset (37.8:62.2%), and gray birds (adult and subadult males) generally went to roost earlier than brown birds (all females and immature males). Rites tended to go to roost earlier on cloudy days. Morning departure from roosts was over a much shorter time than arrivals in the afternoon. Ninety-two percent of the kite roosts were also used by other species of birds for roosting, 8 1% of which were eight species of herons.

Sykes, P.W., Jr.

1985-01-01

345

The Epithelial-Mesenchymal Transition Factor SNAIL Paradoxically Enhances Reprogramming  

PubMed Central

Summary Reprogramming of fibroblasts to induced pluripotent stem cells (iPSCs) entails a mesenchymal to epithelial transition (MET). While attempting to dissect the mechanism of MET during reprogramming, we observed that knockdown (KD) of the epithelial-to-mesenchymal transition (EMT) factor SNAI1 (SNAIL) paradoxically reduced, while overexpression enhanced, reprogramming efficiency in human cells and in mouse cells, depending on strain. We observed nuclear localization of SNAI1 at an early stage of fibroblast reprogramming and using mouse fibroblasts expressing a knockin SNAI1-YFP reporter found cells expressing SNAI1 reprogrammed at higher efficiency. We further demonstrated that SNAI1 binds the let-7 promoter, which may play a role in reduced expression of let-7 microRNAs, enforced expression of which, early in the reprogramming process, compromises efficiency. Our data reveal an unexpected role for the EMT factor SNAI1 in reprogramming somatic cells to pluripotency. PMID:25316190

Unternaehrer, Juli J.; Zhao, Rui; Kim, Kitai; Cesana, Marcella; Powers, John T.; Ratanasirintrawoot, Sutheera; Onder, Tamer; Shibue, Tsukasa; Weinberg, Robert A.; Daley, George Q.

2014-01-01

346

Solar radio-transmitters on snail kites in Florida  

USGS Publications Warehouse

The effectiveness and safety of one- and two-stage solar radio-transmitters in tracking the movements and survival of adult and fledgling Snail Kites (Rostrhamus sociabilis) were evaluated between 1979 and 1983 in southern Florida. Transmitters were attached to birds with back-pack arrangements using teflon ribbon straps. Accessory plastic shields minimized feather coverage of the solar cells. Intact transmitters were seen on birds up to 47 mo after installation. Operating lives ranged from 8 to 21 mo for one-stage, and 10 to 14 mo for two-stage transmitters. Because survival of adult and nestling radio-marked kites was high, we conclude that our transmitter-attachment method had little effect on the birds.

Snyder, N.F.R.; Beissinger, S.R.; Fuller, M.R.

1989-01-01

347

Human freshwater demand for economic activity and ecosystems in Taiwan.  

PubMed

Freshwater is necessary to economic activity, and humans depend on goods and services generated by water-dependent ecosystems. However, national freshwater management usually focuses on direct use of domestic freshwater. With an increasing scarcity of freshwater, attention has turned to two indirect uses of freshwater by humans. The first indirect use is freshwater used by foreign countries when producing products for export. The second use is freshwater required by local ecosystems: human survival and development depend on goods and services generated in these ecosystems. This work adopted Taiwan as a case study. In addition to two widely recognized ecosystem freshwater demands, evapotranspiration and reversed river flow, this study suggests that freshwater is a constituent of some abiotic components, such as groundwater in aquifers, because excessive withdrawal has already caused significant land subsidence in Taiwan. Moreover, the estimated results show that Taiwan's net imports of freshwater through trade amounts to approximately 25% of its total freshwater use for economic production. Integrating industrial policy, trade policy, and national freshwater management is a useful approach for developing strategies to limit the growing use of freshwater in Taiwan. Policy implications are then developed by further analyzing withdrawal sources of freshwater (domestic and foreign) for supporting economic production in Taiwan and identifying the factors (domestic final demand and export) driving freshwater-intensive products. PMID:17899249

Ferng, Jiun-Jiun

2007-12-01

348

Feeding and Growth Responses of the Snail Theba pisana to Dietary Metal Exposure  

Microsoft Academic Search

The effects of dietary exposure to copper (Cu), lead (Pb), and zinc (Zn) on feeding activities, growth response, and mortality\\u000a of Theba pisana snails were studied in 5-week feeding tests. Snails were fed on an artificial diet containing the following Cu, Pb, or Zn\\u000a concentrations: 0, 50, 100, 500, 1000, 5000, 10,000, and 15,000 ?g\\/g dry food. At the end of

K. S. El-Gendy; M. A. Radwan; A. F. Gad

2011-01-01

349

The Giant Snail Achatina fulica as a Candidate Species for Advanced Bioregenerative Life Support Systems  

NASA Astrophysics Data System (ADS)

Maintenance of crew health is of paramount importance for long duration space missions. Weight loss, bone and calcium loss, increased exposure to radiation and oxidative stress are critical concerns that need to be alleviated. Rational nutrition is a resource for mitigating the influence of unfavorable conditions. The insufficiency of vegetarian diet has been examined by the Japanese, Chinese and U.S. developers of bioregenerative life support systems (BLSS). Hence, inclusion of animals such as silkworm in BLSS looks justified. The giant snail is currently under studying as a source of animal food and a species of reducing waste in BLSS. An experimental system to conduct cultivation of giant snail was developed. It was established that there are some reasons to use the giant snails in BLSS. It could be a source of delicious meat. A. fulica is capable of consuming a wide range of feedstuffs including plant residues. Cultivation of snail in the limited volume does not demand the big expenditures of labor. The production of crude edible biomass and protein of A. fulica was 60±15 g and 7±1.8 g respectively per 1 kg of consumed forage (fresh salad leaves, root and leafy tops of carrot). To satisfy daily animal protein needs (30-35 g) a crewman has to consume 260-300 g of snail meat. To produce such amount of snail protein it takes to use 4.3-5.0 kg of plant forage daily. The nutritional composition of A. fulica whole bodies (without shell) and a meal prepared in various ways was quantitatively determined. Protein, carbohydrate, fat acid and ash content percentages were different among samples prepared in various ways. The protein content was highest (68 %) in the dry sample washed with CH3 COOH solution. Taking into consideration the experimental results a conceptual configuration of BLSS with inclusion of giant snail was developed and mass flow rates between compartments were calculated. Keywords: animal food; protein; giant snail; BLSS; conceptual configuration.

Verbitskaya, Olga; Manukovsky, Nickolay; Kovalev, Vladimir

350

Polymorphism and Population Density in the African Land Snail, Limicolaria martensiana.  

PubMed

In natural populations of the African land snail, Limicolaria martensiana, the degree of polymorphism in color and pattern may vary with the density of the population. This could occur because predators eat the snails selectively and use past experience as a guide in finding further prey. Hence contrasting color forms may be at an advantage in dense populations where predators would have ample opportunity to learn to recognize prey. PMID:17737105

Owen, D F

1963-05-10

351

Dose-Dependent Effects of Cadmium on the Growth of Snails in Toxicity Bioassays  

Microsoft Academic Search

.   The effects on survival and growth of exposure to cadmium (Cd) in the food were analyzed in juvenile snails (age one month,\\u000a mean weight 1 g) of the two subspecies Helix aspersa aspersa (H.a.a.) and H. aspersa maxima (H.a.m.). The experiments lasted for four weeks and the animals were fed with special snail food containing 0-, 50-, 100-,\\u000a 200-,

A. Gomot

1997-01-01

352

Best Management Practices for Freshwater Pond Aquaculture  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter in the book “Environmental Best Management Practices for Aquaculture” describes freshwater pond aquaculture systems and management practices to reduce environmental impacts of pond aquaculture. Pond aquaculture systems for channel catfish, crawfish, baitfish, hybrid striped bass, and o...

353

Global diversity of amphibians (Amphibia) in freshwater  

Microsoft Academic Search

This article present a review of species numbers, biogeographic patterns and evolutionary trends of amphibians in freshwater.\\u000a Although most amphibians live in freshwater in at least their larval phase, many species have evolved different degrees of\\u000a independence from water including direct terrestrial development and viviparity. Of a total of 5,828 amphibian species considered\\u000a here, 4,117 are aquatic in that they

Miguel Vences; Jörn Köhler

2008-01-01

354

Global diversity of amphibians (Amphibia) in freshwater  

Microsoft Academic Search

This article present a review of species numbers, biogeographic patterns and evolutionary trends of amphibians in freshwater.\\u000a Although most amphibians live in freshwater in at least their larval phase, many species have evolved different degrees of\\u000a independence from water including direct terrestrial development and viviparity. Of a total of 5,828 amphibian species considered\\u000a here, 4,117 are aquatic in that they

Miguel Vences; Jörn Köhler

355

Localization of the neuropeptide APGWamide in gastropod molluscs by in situ hybridization and immunocytochemistry.  

PubMed

The amidated tetrapeptide Ala-Pro-Gly-Trp-NH2 (APGWamide) plays a key role in the control of male copulation behavior in the basommatophoran pulmonate freshwater snail Lymnaea stagnalis. The morphological basis for a conserved role of APGWamide in the control of male reproduction in gastropod molluscs is presented. The prosobranch Littorina littorea, the opisthobranch Aplysia californica, the basommatophoran pulmonate Bulinus truncatus, and the stylommatophoran pulmonates Arion ater and Limax maximus have been examined for the presence of APGWamide producing neurons using immunocytochemistry and in situ hybridization. In all species investigated a cluster of APGWamide expressing neurons is present in the anteromedial region of the cerebral ganglia. The asymmetrical distribution which exists in Lymnaea and which coincides with the innervation of the asymmetrically located penial complex is also found in the opisthobranch Aplysia, as well as in the stylommatophoran pulmonate slugs Arion and Limax, in which APGWamide immunoreactive neurons are only found in the mesocerebrum of the right cerebral ganglion. APGWamide immunoreactive varicose fibers innervate muscles of the male accessory sex organs in Bulinus and Aplysia, confirming the hypothesis that APGWamide may be a biochemically and functionally conserved factor in the regulation of gastropod mollusc reproduction. PMID:9473361

de Lange, R P; van Minnen, J

1998-02-01

356

Are Sick Individuals Weak Competitors? Competitive Ability of Snails Parasitized by a Gigantism-Inducing Trematode  

PubMed Central

Parasitized individuals are often expected to be poor competitors because they are weakened by infections. Many trematode species, however, although extensively exploiting their mollusc hosts, also induce gigantism (increased host size) by diverting host resources towards growth instead of reproduction. In such systems, alternatively to reduced competitive ability due to negative effects of parasitism on host performance, larger size could allow more efficient resource acquisition and thus increase the relative competitive ability of host individuals. We addressed this hypothesis by testing the effect of a trematode parasite Diplostomum pseudospathaceum on the competitive ability of its snail host Lymnaea stagnalis. We experimentally examined the growth of snails kept in pairs in relation to their infection status and intensity of resource competition (i.e. food availability). We found that parasitized snails grew faster and their reproduction was reduced compared to unparasitized individuals indicating parasite-induced gigantism. However, growth of the snails was faster when competing with parasitized individuals compared to unparasitized snails indicating reduced competitive ability due to parasitism. The latter effect, however, was relatively weak suggesting that the effects of the parasite on snail physiology may partly override each other in determining competitive ability. PMID:24205383

Seppälä, Otto; Karvonen, Anssi; Kuosa, Marja; Haataja, Maarit; Jokela, Jukka

2013-01-01

357

Molluscicidal activity of vulgarone B against ram's horn snail (Planorbella trivolvis).  

PubMed

The ram's horn snail (Planorbella trivolvis (Say)) is an intermediate host for a digenetic trematode (Bolbophorus confusus (Krause) Dubois) that has recently been discovered to be a significant problem in commercial channel catfish (Ictalurus punctatus Raf) production ponds in the Mississippi Delta region in the USA. In these catfish ponds, the digenetic life cycle of this parasitic trematode involves two intermediate hosts, the ram's horn snail and the channel catfish, and the final host, the American white pelican (Pelecanus erythrorhynchos Gmelin). One approach to eradicate this problem is to disrupt the life cycle of the parasitic trematodes by eliminating the snails. During our search for natural-product-based molluscicides to control the snails in the catfish ponds, vulgarone B, isolated from the steam distillate of the aerial parts of the plant Artemisia douglasiana Besser (Asteraceae), was found to be active towards the snails with a LC50 of ca 24 microM. Channel catfish toxicity studies indicated a LC50 of ca 207 microM. Vulgarone B may be an environmentally acceptable alternative for snail control in aquaculture. PMID:15154515

Meepagala, Kumudini M; Sturtz, George; Mischke, Charles C; Wise, David; Duke, Stephen O

2004-05-01

358

Studies of the snail vectors of bilharziasis mansoni in north-eastern Brazil  

PubMed Central

The authors describe the bilharziasis endemic areas in north-eastern Brazil, giving the rainfall and general characteristics of the climate. The life-cycles of the two snail vectors—Australorbis glabratus and Tropicorbis centimetralis—in Pernambuco are described. Considerable attention is given to the effects on the snails of the annual drought, which causes many of the habitats to dry up and seriously affects the snail life-cycles and survival patterns. The snails are able to populate habitats that are dry for 5-7 months every year. They survive during the dry season in the protection of debris, vegetation, etc. A. glabratus is more susceptible to infection with Schistosoma mansoni than is T. centimetralis, but the latter is an effective vector, nevertheless, probably because it often occurs in very large numbers. A. glabratus with mature infections die or lose their infections when removed from the water for 20-30 days. Immature parasites are not killed under the same conditions. Infection with S. mansoni injures the snails and may kill them. It also reduces the reproductive capacity of the vectors, but it does not permanently castrate them. The epidemiological significance of these findings and their meaning in terms of snail control are discussed. PMID:13573116

Barbosa, Frederico S.; Olivier, Louis

1958-01-01

359

Bacterial diversity in different regions of gastrointestinal tract of Giant African Snail (Achatina fulica)  

PubMed Central

The gastrointestinal (GI) tract of invasive land snail Achatina fulica is known to harbor metabolically active bacterial communities. In this study, we assessed the bacterial diversity in the different regions of GI tract of Giant African snail, A. fulica by culture-independent and culture-dependent methods. Five 16S rRNA gene libraries from different regions of GI tract of active snails indicated that sequences affiliated to phylum ?-Proteobacteria dominated the esophagus, crop, intestine, and rectum libraries, whereas sequences affiliated to Tenericutes dominated the stomach library. On phylogenetic analysis, 30, 27, 9, 27, and 25 operational taxonomic units (OTUs) from esophagus, crop, stomach, intestine, and rectum libraries were identified, respectively. Estimations of the total bacterial diversity covered along with environmental cluster analysis showed highest bacterial diversity in the esophagus and lowest in the stomach. Thirty-three distinct bacterial isolates were obtained, which belonged to 12 genera of two major bacterial phyla namely ?-Proteobacteria and Firmicutes. Among these, Lactococcus lactis and Kurthia gibsonii were the dominant bacteria present in all GI tract regions. Quantitative real-time polymerase chain reaction (qPCR) analysis indicated significant differences in bacterial load in different GI tract regions of active and estivating snails. The difference in the bacterial load between the intestines of active and estivating snail was maximum. Principal component analysis (PCA) of terminal restriction fragment length polymorphism suggested that bacterial community structure changes only in intestine when snail enters estivation state. PMID:23233413

Pawar, Kiran D; Banskar, Sunil; Rane, Shailendra D; Charan, Shakti S; Kulkarni, Girish J; Sawant, Shailesh S; Ghate, Hemant V; Patole, Milind S; Shouche, Yogesh S

2012-01-01

360

Snail2/Slug cooperates with Polycomb repressive complex 2 (PRC2) to regulate neural crest development.  

PubMed

Neural crest cells arise from the border of the neural plate and epidermal ectoderm, migrate extensively and differentiate into diverse cell types during vertebrate embryogenesis. Although much has been learnt about growth factor signals and gene regulatory networks that regulate neural crest development, limited information is available on how epigenetic mechanisms control this process. In this study, we show that Polycomb repressive complex 2 (PRC2) cooperates with the transcription factor Snail2/Slug to modulate neural crest development in Xenopus. The PRC2 core components Eed, Ezh2 and Suz12 are expressed in the neural crest cells and are required for neural crest marker expression. Knockdown of Ezh2, the catalytic subunit of PRC2 for histone H3K27 methylation, results in defects in neural crest specification, migration and craniofacial cartilage formation. EZH2 interacts directly with Snail2, and Snail2 fails to expand the neural crest domains in the absence of Ezh2. Chromatin immunoprecipitation analysis shows that Snail2 regulates EZH2 occupancy and histone H3K27 trimethylation levels at the promoter region of the Snail2 target E-cadherin. Our results indicate that Snail2 cooperates with EZH2 and PRC2 to control expression of the genes important for neural crest specification and migration during neural crest development. PMID:25617436

Tien, Chih-Liang; Jones, Amanda; Wang, Hengbin; Gerigk, Magda; Nozell, Susan; Chang, Chenbei

2015-02-15

361

Effects of dietary exposure to forest pesticides on the brown garden snail Helix aspersa mueller  

SciTech Connect

Brown garden snails, Helix aspersa, were fed prepared diets with 12 pesticides used in forest spraying practices where endangered arboreal and terrestrial snails may be at risk. Acephate, atrazine, glyphosate, hexazinone, and picloram were not lethal at concentrations of 5,000 mg/kg in 14-day screening tests. The remaining seven pesticides, lethal to 13-100% of the tested snails at 5,000 mg/kg, were evaluated in 10-day definitive feeding tests. Azinphosmethyl (Guthion) and aminocarb were the most toxic, with 10-day LC50s of 188 and 313 mg/kg, respectively. Paraquat, trichlorfon and fenitrothion had 10-day LC50s of 659, 664, and 7,058 mg/kg respectively. Avoidance of pesticide-containing foods occurred, e.g., 10-day LC50s of >10,000 mg/kg for carbaryl and ethyl parathion. Significant descreases (p<0.05) in snail weight (total, shell-only, body-only) or shell diameter were accompanied by a significant decrease in the amount of food consumed/snail/day. Concentrations of pesticide in tissues were measured in snails exposed to atrazine and azinphosmethyl; there was no bioaccumulation. (Copyright (c) 1994 Springer-Verlag New York Inc.)

Schuytema, G.S.; Nebeker, A.V.; Griffis, W.L.

1994-01-01

362

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

PubMed

We purposively selected 39 sampling sites along the Mara River and its two perennial tributaries of Amala and Nyangores and sampled snails. In addition, water physicochemical parameters (temperature, turbidity, dissolved oxygen, conductivity, alkalinity, salinity and pH) were taken to establish their influence on the snail abundance and habitat preference. Out of the 39 sites sampled, 10 (25.6%) had snails. The snail species encountered included Biomphalaria pfeifferi Krauss - the intermediate host of Schistosoma mansoni Sambon, Bulinus africanus - the intermediate host of Schistosoma haematobium, and Lymnaea natalensis Krauss - the intermediate host of both Fasciola gigantica and F. hepatica Cobbold. Ceratophallus spp., a non-vector snail was also encountered. Most (61.0%) of the snails were encountered in streamside pools. Schistosomiasis-transmitting host snails, B. pfeifferi and B. africanus, were fewer than fascioliasis-transmitting Lymnaea species. All the four different snail species were found to be attached to different aquatic weeds, with B. pfeifferi accounting for over half (61.1%) of the snails attached to the sedge, followed by B. africanus and Lymnaea spp., accounting for 22.2 and 16.7%, respectively. Ceratophallus spp. were non-existent in sedge. The results from this preliminary study show that snails intermediate hosts of schistosomiasis and fascioliasis exists in different habitats, in few areas along the Mara River, though their densities are still low to have any noticeable impacts on disease transmission in case they are infected. The mere presence of the vector snails in these focal regions calls for their immediate control and institution of proper regulations, management, and education among the locals that can help curtail the spread of the snails and also schistosomiasis and fascioliasis within the Mara River basin. PMID:25405008

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

2014-01-01

363

The molecular phylogeny of freshwater Dothideomycetes  

PubMed Central

The freshwater Dothideomycetes species are an ecological rather than taxonomic group and comprise approximately 178 meiosporic and mitosporic species. Due to convergent or parallel morphological adaptations to aquatic habitats, it is difficult to determine phylogenetic relationships among freshwater taxa and among freshwater, marine and terrestrial taxa based solely on morphology. We conducted molecular sequence-based phylogenetic analyses using nuclear ribosomal sequences (SSU and/or LSU) for 84 isolates of described and undescribed freshwater Dothideomycetes and 85 additional taxa representative of the major orders and families of Dothideomycetes. Results indicated that this ecological group is not monophyletic and all the freshwater taxa, except three aeroaquatic Tubeufiaceae, occur in Pleosporomycetidae as opposed to Dothideomycetidae. Four clades comprised of only freshwater taxa were recovered. The largest of these is the Jahnulales clade consisting of 13 species, two of which are the anamorphs Brachiosphaera tropicalis and Xylomyces chlamydosporus. The second most speciose clade is the Lindgomycetaceae clade consisting of nine taxa including the anamorph Taeniolella typhoides. The Lindgomycetaceae clade consists of taxa formerly described in Massarina, Lophiostoma, and Massariosphaeria e.g., Massarina ingoldiana, Lophiostoma breviappendiculatum, and Massariosphaeria typhicola and several newly described and undescribed taxa. The aquatic family Amniculicolaceae, including three species of Amniculicola, Semimassariosphaeria typhicola and the anamorph, Anguillospora longissima, was well supported. A fourth clade of freshwater species consisting of Tingoldiago graminicola, Lentithecium aquaticum, L. arundinaceum and undescribed taxon A-369-2b was not well supported with maximum likelihood bootstrap and Bayesian posterior probability. Eight freshwater taxa occurred along with terrestrial species in the Lophiostoma clades 1 and 2. Two taxa lacking statistical support for their placement with any taxa included in this study are considered singletons within Pleosporomycetidae. These singletons, Ocala scalariformis, and Lepidopterella palustris, are morphologically distinct from other taxa in Pleosporomycetidae. This study suggests that freshwater Dothideomycetes are related to terrestrial taxa and have adapted to freshwater habitats numerous times. In some cases (Jahnulales and Lindgomycetaceae), species radiation appears to have occurred. Additional collections and molecular study are required to further clarify the phylogeny of this interesting ecological group. PMID:20169028

Shearer, C.A.; Raja, H.A.; Miller, A.N.; Nelson, P.; Tanaka, K.; Hirayama, K.; Marvanová, L.; Hyde, K.D.; Zhang, Y.

2009-01-01

364

Effects of Washing Produce Contaminated with the Snail and Slug Hosts of Angiostrongylus cantonensis with Three Common Household Solutions  

PubMed Central

The emerging infectious disease angiostrongyliasis (rat lungworm disease) is caused by ingesting snails and slugs infected by the nematode Angiostrongylus cantonensis. The definitive hosts of A. cantonensis are rats and the obligatory intermediate hosts are slugs and snails. Many cases result from accidentally ingesting infected snails or slugs on produce (eg, lettuce). This study assessed three readily available household products as washing solutions for removing snails and slugs from produce (romaine lettuce) to lower the probability of accidentally ingesting them. The solutions were acetic acid (vinegar), sodium hypochlorite (bleach), and sodium chloride (domestic salt). Snail and slug species known to be intermediate hosts and that are common in the Hawaiian Islands were used in the experiments: the alien snail Succinea tenella, the alien semi-slug Parmarion martensi, and the alien slugs Veronicella cubensis and Deroceras laeve. None of the products was any more effective than washing and rinsing with tap water alone. Most snails and slugs were removed after treatment but some remained on the lettuce even after washing and rinsing the produce. Only washing, rinsing, and then rinsing each leaf individually resulted in complete removal of all snails and slugs. The study did not address removal of any remaining slime left by the snails and slugs, nor did it address killing of worms. PMID:23901391

Yeung, Norine W; Hayes, Kenneth A

2013-01-01

365

Commissioned Review. Carbon: freshwater plants  

USGS Publications Warehouse

?13C values for freshwater aquatic plant matter varies from ?11 to ?50‰ and is not a clear indicator of photosynthetic pathway as in terrestrial plants. Several factors affect ?13C of aquatic plant matter. These include: (1) The ?13C signature of the source carbon has been observed to range from +1‰ for HCO3? derived from limestone to ?30‰ for CO2 derived from respiration. (2) Some plants assimilate HCO3?, which is –7 to –11‰ less negative than CO2. (3) C3, C4, and CAM photosynthetic pathways are present in aquatic plants. (4) Diffusional resistances are orders of magnitude greater in the aquatic environment than in the aerial environment. The greater viscosity of water acts to reduce mixing of the carbon pool in the boundary layer with that of the bulk solution. In effect, many aquatic plants draw from a finite carbon pool, and as in terrestrial plants growing in a closed system, biochemical discrimination is reduced. In standing water, this factor results in most aquatic plants having a ?13C value similar to the source carbon. Using Farquhar's equation and other physiological data, it is possible to use ?13C values to evaluate various parameters affecting photosynthesis, such as limitations imposed by CO2 diffusion and carbon source.

Keeley, J.E.; Sandquist, D.R.

1992-01-01

366

Bioaccumulation and toxicity of copper in outdoor freshwater microcosms.  

PubMed

This study characterizes the effects of copper (Cu) on Florida apple snails (Pomacea paludosa) and mosquito fish (Gambusia affinis) using a replicated outdoor microcosm design. Soils used in this study were collected from two Cu-enriched citrus agricultural sites in South Florida (Agler property (AGLR) in St. Lucie County and Sunrise Boys property (SRB) in Palm Beach County) and a reference site (Equus property) in St. Lucie County. The study included a 5-week aging phase, an 11 month exposure phase, and a 3 month post-treatment (exposure) phase. The aging phase was initiated by flooding agricultural soils with rainwater in 4 m(3) fiberglass microcosm tanks. Introducing juvenile apple snails (?7 d old) and mosquito fish (2-3 cm) into the microcosm tanks initiated the exposure phase. Survival, growth, and reproduction of apple snails and fish, and Cu uptake in apple snails, fish, and periphyton were determined in this study. Water chemistry (e.g., dissolved Cu concentration, dissolved organic carbon and dissolved oxygen concentrations, pH, hardness, alkalinity, etc.) was measured daily or weekly during the study. Initial soil Cu concentrations in Equus, SRB, and AGLR microcosms were 7, 55, and 99 mg/kg dw, respectively. Dissolved Cu concentrations in Equus, SRB and AGLR microcosms at the beginning of the study were 3, 82, and 43 ?g/L, respectively and decreased to low saturation levels of about ?9 ?g/L Cu after the first 3 months of the study. The decrease of dissolved Cu concentrations was likely due to the dilution of rainwater. Snail and fish mortality appeared to be higher in SRB microcosms than in Equus and AGLR microcosms. There was no significant difference in growth of the snails between treatments. Snail growth data followed the von Bertalanffy Model. The maximum shell length, shell height, and shell width of the snails calculated by the von Bertalanffy Model (L(?)) were 2.76, 2.05, and 2.18 cm, respectively. The maximum wet weight was 9.38 g. Growth rate (k) of the snails increased in order of shell height (0.459), shell length (0.550), and shell weight (0.598). There was no reproduction in the snails in any treatments including the reference during the exposure phase. However, Cu did not affect reproduction of fish during this period. Copper concentrations in periphyton from Equus, SRB, and AGLR microcosms ranged from 2 to 62, 31 to 371, and 13 to 478 mg/kg, respectively. Copper concentrations in fish at the beginning, days 30 and 150 of the study ranged from 3.19 to 7.53 mg/kg and were not significantly different from the different treatments. Average Cu concentrations in the soft tissue of dead snails from SRB and AGLR microcosms were 4602 mg/kg dw (ranged from 2913 to 8370 mg/kg dw) and 2824 mg/kg dw (ranged from 2118 to 3600 mg/kg dw), respectively. The Cu concentrations in the soft tissue of dead snails found in this study were higher than the tissue Cu concentrations in live aquatic organisms reported in the literature. These high Cu concentrations in edible apple snail soft tissue might pose a risk to Florida apple snail predators, including the snail kite. The post-exposure phase, with snails exposed to only water (i.e., no soils) showed depuration of copper from apple snails and reproduction in all treatments. PMID:21345490

Hoang, Tham C; Pryor, Rachel L; Rand, Gary M; Frakes, Robert A

2011-05-01

367

Extraction of Freshwater and Energy from Atmosphere  

E-print Network

Author offers and researches a new, cheap method for the extraction of freshwater from the Earth atmosphere. The suggected method is fundamentally dictinct from all existing methods that extract freshwater from air. All other industrial methods extract water from a saline water source (in most cases from seawater). This new method may be used at any point in the Earth except Polar Zones. It does not require long-distance freshwater transportation. If seawater is not utilized for increasing its productivity, this inexpensive new method is very environment-friendly. The author method has two working versions: (1) the first variant the warm (hot) atmospheric air is lifted by the inflatable tube in a high altitude and atmospheric steam is condenced into freswater: (2) in the second version, the warm air is pumped 20-30 meters under the sea-surface. In the first version, wind and solar heating of air are used for causing air flow. In version (2) wind and propeller are used for causing air movment. The first method does not need energy, the second needs a small amount. Moreover, in variant (1) the freshwater has a high pressure (>30 or more atm.) and can be used for production of energy such as electricity and in that way the freshwater cost is lower. For increasing the productivity the seawater is injected into air and solar air heater may be used. The solar air heater produces a huge amount of electricity as a very powerful electricity generation plant. The offered electricity installation in 100 - 200 times cheaper than any common electric plant of equivalent output. Key words: Extraction freshwater, method of getting freshwater, receiving energy from atmosphere, powerful renewal electric plant.

Alexander Bolonkin

2007-04-19

368

Deriving Freshwater Quality Criteria for Iron, Lead, Nickel, and Zinc for Protection of Aquatic Life in Malaysia  

PubMed Central

Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC50 values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9??g L?1, respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4??g?L?1 and 9.0, 2.0, 19.9, and 36.7??g?L?1, respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively. PMID:22919358

Shuhaimi-Othman, M.; Nadzifah, Y.; Nur-Amalina, R.; Umirah, N. S.

2012-01-01

369

Electrophoretic studies on the digestive gland esterases of some biomphalarid and lymnaeid snails  

PubMed Central

Because of the problems encountered in the classification of snails of medical importance, biochemical methods have been sought to help clarify the situation. Of these, the separation of the enzymes of adult snails by electrophoresis seems the most promising but very few attempts have been made so far to use the results for taxonomic studies. The purpose of the present study was to evaluate the use of the enzyme systems of neotropical planorbid and of lymnaeid snails to elucidate their taxonomy and also snail—schistosome relationships at the species and population levels. The findings show the characteristic electrophoretic patterns of digestive gland esterases of the planorbid and lymnaeid snails used, as well as their variation and the level of such variation among certain populations and the consistency of the patterns among others. The results also show that, in general, the extent of variation between some populations of the same species is greater than the differences between species of the same group. However, at the specific level, there are similarities suggesting close relationships between some populations of Biomphalaria glabrata and B. tenagophila on the one hand, and of certain populations of B. peregrina and of B. obstructa on the other hand. The present study has thrown some light on the question of electrophoretic variation in enzymes, and the ways in which this can be applied to studies of the genetics of snails. A correlation is suggested between certain patterns that indicate biochemical similarities or differences among the planorbid snail populations and the susceptibility of the species or the population to infection with the schistosomes. ImagesFig. 4Fig. 1Fig. 3Fig. 2 PMID:5317015

Malek, Emile A.; File, Sharon K.

1971-01-01

370

AVES.NET: The Freshwater Dinoflagellates  

NSDL National Science Digital Library

Hosted by AVES.NET, this website about Freshwater Dinoflagellates was created by Victor W. Fazio III and Dr. Susan Carty of Heidelberg College (Tiffin, Ohio). Two main attractions of this site are the Freshwater Dinoflagellate Image Archive, and the Recent Additions-Freshwater Dinoflagellate Images 2003 (from the 2003-04 winter field season). Individual Dinoflagellate image pages generally include a ventral view, dorsal view, or both, and the pages featuring species from Ohio include county distribution maps. Site visitors can email Dr. Carty for permission to use any of the images. The website also contains a List of Freshwater Dinoflagellates in Ohio, some of which link to the individual image pages. Additionally, the site offers a Review of Online Images of Freshwater Dinoflagellates including links to many other host sites, and a link to an online article by Dr. Susan Carty and Daniel E. Wujek entitled _A New Species of Peridinium and New Records of Dinoflagellates and Silica-Scaled Chrysophytes from Belize._ [NL

Carty, Susan; Fazio, Victor W. (1962-)

371

Dispersion Of Crude Oil And Petroleum Products In Freshwater  

EPA Science Inventory

The objective of this research was to investigate the relationship between dispersion effectiveness in freshwater and the surfactant composition for fresh and weathered crude oil. Although limited research on the chemical dispersion of crude oil and petroleum products in freshwat...

372

A phylogeny of the land snails (Gastropoda: Pulmonata).  

PubMed Central

We have undertaken the first large-scale molecular phylogenetic analysis of the Stylommatophora. Sequences of the ribosomal RNA gene-cluster were examined in 104 species of snails and slugs from 50 families, encompassing all the currently recognized major groups. It allows an independent test of the present classification based on morphology. At the level of families our molecular phylogeny closely supports the current taxonomy, but the deep branches within the tree do not. Surprisingly, a single assemblage including the families Achatinidae, Subulinidae and Streptaxidae lies near the base of the tree, forming a sister group to all remaining stylommatophorans. This primary division into 'achatinoid' and 'non-achatinoid' taxa is unexpected, and demands a radical reinterpretation of early stylommatophoran evolution. In particular, the Orthurethra appear to be relatively advanced within the 'non-achatinoid clade', and broadly equivalent to other super-familial clusters. This indicates that supposedly primitive features such as the orthurethran kidney are derived. The molecular tree also suggests that the origin of the Stylommatophora is much earlier than the main period of their diversification. PMID:11270439

Wade, C. M.; Mordan, P. B.; Clarke, B.

2001-01-01

373

Distribution of fasciolosis in Kansas, with results of experimental snail susceptibility studies.  

PubMed

A total of 278 veterinarians throughout Kansas were sent mail-in survey forms asking specific questions relating to their experience with fasciolosis in their practice area. Replies were received from 178 (64%) veterinarians representing six practice types; one-third reported having seen cases of fasciolosis in their practice. The results of our survey indicate that the majority of the cattle diagnosed with liver fluke disease in Kansas are imported from other areas of the USA. However, in both central and southeastern regions of Kansas, some cattle that had never been out of the state were infected with Fasciola hepatica. Thus, these areas of Kansas should be considered endemic for liver fluke disease. Methods of diagnosis, types of operations, and improvements seen after treatment were also discussed. In order to ascertain the existence of one or more possible snail intermediate hosts within Kansas, five species of lymnaeid snails were collected from central and southeastern parts of the state and tested for their susceptibility to infection by Fasciola hepatica. The snails collected included Pseudosuccinea columella, Fossaria obrussa, Fossaria bulimoides, Fossaria parva and Fossaria dalli. Of these, Pseudosuccinea columella and Fossaria bulimoides proved susceptible to experimental infection by Fasciola hepatica. Metacercariae obtained from experimentally infected snails were used to infect both a weanling calf thereby completing the life cycle of the parasite. This report is the first to identify the existence of suitable snail intermediate hosts for Fasciola hepatica in Kansas. PMID:7754605

McKown, R D; Ridley, R K

1995-02-01

374

Evaluation of environmental methods to control snails in an irrigation system in Central Morocco.  

PubMed

The Moroccan Ministry of Public Health has launched a programme to eliminate schistosomiasis. One of the components in this process is the control of Bulinus truncatus, the intermediate host snail of Schistosoma haematobium. We evaluated three environmentally safe measures to control B. truncatus in siphon boxes, the main breeding sites for these snails in the Tessaout Amont irrigation system. The first method involved covering the siphon boxes to exclude light and reduce algal growth, the second consisted of increasing the frequency of emptying and cleaning the siphon boxes, and the third method increased water velocity to hinder the establishment of the intermediate hosts. The results showed that covering had a pronounced effect on snail and egg mass density, was accepted by the local community and prevented water contact. Cleaning the siphons three times during the irrigation season led to a reduction in snail density although it was not statistically significant and recolonization was rapid. Increasing water velocity by reducing the dimensions of siphon boxes delayed recolonization, but such a control measure can be applied only in specific situations where it does not pose hydraulic problems. The three interventions were selectively effective against B. truncatus, whereas other snails such as Physa acuta and Lymnaea peregra were hardly affected. Covering, the most promising control measure, could be useful in the Moroccan schistosomiasis eradication programme. However, further investigations are needed to assess its impact on water quality. PMID:10995096

Laamrani, H; Khallaayoune, K; Boelee, E; Laghroubi, M M; Madsen, H; Gryseels, B

2000-08-01

375

Genetic Variation between Biomphalaria alexandrina Snails Susceptible and Resistant to Schistosoma mansoni Infection  

PubMed Central

Much effort has been made to control schistosomiasis infection in Egypt. However, enduring effects from such strategies have not yet been achieved. In this study, we sought to determine the genetic variability related to the interaction between Biomphalaria alexandrina snails and Schistosoma mansoni. Using RAPD-PCR with eight (10?mers) random primers, we were able to determine the polymorphic markers that differed between snails susceptible and resistant to Schistosoma mansoni infection using five primers out of the eight. Our results suggest that the RAPD-PCR technique is an efficient means by which to compare genomes and to detect genetic variations between schistosomiasis intermediate hosts. The RAPD technique with the above-noted primers can identify genomic markers that are specifically related to the Biomphalaria alexandrina/Schistosoma mansoni relationship in the absence of specific nucleotide sequence information. This approach could be used in epidemiologic surveys to investigate genetic diversity among Biomphalaria alexandrina snails. The ability to determine resistant markers in Biomphalaria alexandrina snails could potentially lead to further studies that use refractory snails as agents to control the spread of schistosomiasis. PMID:23878796

El-Nassery, Suzanne M. F.; Abou-El-Naga, Iman F.; Allam, Sonia R.; Shaat, Eman A.; Mady, Rasha F. M.

2013-01-01

376

Fascioliasis Control: In Vivo and In Vitro Phytotherapy of Vector Snail to Kill Fasciola Larva  

PubMed Central

Snail is one of the important components of an aquatic ecosystem, it acts as intermediate host of Fasciola species. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. Life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria in the snail body. In vivo and in vitro toxicity of the plant products and their active component such as citral, ferulic acid, umbelliferone, azadirachtin, and allicin against larva of Fasciola in infected snail Lymnaea acuminata were tested. Mortality of larvae were observed at 2?h, 4?h, 6?h, and 8?h, of treatment. In in vivo treatment, azadirachtin caused highest mortality in redia and cercaria larva (8?h, LC50 0.11, and 0.05?mg/L) whereas in in vitro condition allicin was highly toxic against redia and cercaria (8?h, LC50 0.01, and 0.009?mg/L). Toxicity of citral was lowest against redia and cercaria larva. PMID:22132306

Sunita, Kumari; Singh, D. K.

2011-01-01

377

Inhibiting interactions of lysine demethylase LSD1 with snail/slug blocks cancer cell invasion.  

PubMed

The process of epithelial-mesenchymal transition (EMT) which is required for cancer cell invasion is regulated by a family of E-box-binding transcription repressors, which include Snail (SNAIL1) and Slug (SNAI2). Snail appears to repress the expression of the EMT marker E-cadherin by epigenetic mechanisms dependent on the interaction of its N-terminal SNAG domain with chromatin-modifying proteins including lysine-specific demethylase 1 (LSD1/KDM1A). We assessed whether blocking Snail/Slug-LSD1 interaction by treatment with Parnate, an enzymatic inhibitor of LSD1, or TAT-SNAG, a cell-permeable peptide corresponding to the SNAG domain of Slug, suppresses the motility and invasiveness of cancer cells of different origin and genetic background. We show here that either treatment blocked Slug-dependent repression of the E-cadherin promoter and inhibited the motility and invasion of tumor cell lines without any effect on their proliferation. These effects correlated with induction of epithelial and repression of mesenchymal markers and were phenocopied by LSD1 or Slug downregulation. Parnate treatment also inhibited bone marrow homing/engraftment of Slug-expressing K562 cells. Together, these studies support the concept that targeting Snail/Slug-dependent transcription repression complexes may lead to the development of novel drugs selectively inhibiting the invasive potential of cancer cells. PMID:23054398

Ferrari-Amorotti, Giovanna; Fragliasso, Valentina; Esteki, Roza; Prudente, Zelia; Soliera, Angela Rachele; Cattelani, Sara; Manzotti, Gloria; Grisendi, Giulia; Dominici, Massimo; Pieraccioli, Marco; Raschellà, Giuseppe; Chiodoni, Claudia; Colombo, Mario Paolo; Calabretta, Bruno

2013-01-01

378

Isolation of a phosphoryl choline-binding protein from the hemolymph of the snail, Achatina fulica.  

PubMed

A phosphorylcholine-binding protein from the hemolymph of the snail Achatina fulica was purified to near homogeneity using a Sepharose phenylphosphorylcholine affinity column. The protein bound to the affinity column was eluted with 5 mM phosphorylcholine as a single symmetrical peak. The purified protein (400 Kda) contained 35-40% carbohydrate. On SDS-PAGE the protein separated into two bands of 20 and 24 Kda, and had a pI of 5.9. On immunodiffusion, antiserum to the snail phosphorylcholine binding protein did not cross-react against other phosphorylcholine binding proteins, like rat serum phosphorylcholine-binding protein (PCBP), limulus C-reactive protein (CRP), or human CRP. On pretreatment of the snail hemolymph with this antiserum, the hemagglutination titer of the hemolymph was markedly decreased. The purified snail phosphorylcholine binding protein agglutinated rabbit erythrocytes in the absence of divalent cation (Ca+2) but trace amount of Ca+2 increased its binding. The strongest inhibitor of the agglutination reaction was lactose, followed by melibiose and 2-deoxygalactose. The relationships of the snail phosphorylcholine binding protein to other hemolymph agglutinins and to CRPs are discussed in light of common phylogeny. PMID:1773848

Mandal, C; Biswas, M; Nagpurkar, A; Mookerjea, S

1991-01-01

379

Specialized insulin is used for chemical warfare by fish-hunting cone snails.  

PubMed

More than 100 species of venomous cone snails (genus Conus) are highly effective predators of fish. The vast majority of venom components identified and functionally characterized to date are neurotoxins specifically targeted to receptors, ion channels, and transporters in the nervous system of prey, predators, or competitors. Here we describe a venom component targeting energy metabolism, a radically different mechanism. Two fish-hunting cone snails, Conus geographus and Conus tulipa, have evolved specialized insulins that are expressed as major components of their venoms. These insulins are distinctive in having much greater similarity to fish insulins than to the molluscan hormone and are unique in that posttranslational modifications characteristic of conotoxins (hydroxyproline, ?-carboxyglutamate) are present. When injected into fish, the venom insulin elicits hypoglycemic shock, a condition characterized by dangerously low blood glucose. Our evidence suggests that insulin is specifically used as a weapon for prey capture by a subset of fish-hunting cone snails that use a net strategy to capture prey. Insulin appears to be a component of the nirvana cabal, a toxin combination in these venoms that is released into the water to disorient schools of small fish, making them easier to engulf with the snail's distended false mouth, which functions as a net. If an entire school of fish simultaneously experiences hypoglycemic shock, this should directly facilitate capture by the predatory snail. PMID:25605914

Safavi-Hemami, Helena; Gajewiak, Joanna; Karanth, Santhosh; Robinson, Samuel D; Ueberheide, Beatrix; Douglass, Adam D; Schlegel, Amnon; Imperial, Julita S; Watkins, Maren; Bandyopadhyay, Pradip K; Yandell, Mark; Li, Qing; Purcell, Anthony W; Norton, Raymond S; Ellgaard, Lars; Olivera, Baldomero M

2015-02-10

380

Ligand-activated PPAR? modulates the migration and invasion of melanoma cells by regulating Snail expression  

PubMed Central

Peroxisome proliferator-activated receptor (PPAR) ? is implicated in the carcinogenesis of several types of cancer. However, the therapeutic efficacy of PPAR? ligands against cancer progression is unclear. Here, we showed that PPAR? modulates the migration and invasion of melanoma cells by up-regulating Snail expression. Activation of PPAR? by GW501516, a specific ligand for PPAR?, significantly increased the migration and invasion of highly metastatic A375SM cells, but not that of low metastatic A375P cells. The migration- and invasion-promoting effects of PPAR? on A375SM cells was associated with increased Snail expression, which was accompanied by a decrease in E-cadherin expression. Furthermore, a significant concentration- and time-dependent increase in the levels of Snail mRNA and protein was observed in A375SM cells (but not A375P cells) treated with GW501516. The effects of GW501516 were almost completely abrogated by a small interfering RNA against PPAR?, suggesting that PPAR? mediates the effects of GW501516. Activation of PPAR? in SK-MEL-2 and SK-MEL-5 (but not SK-MEL-3) melanoma cell lines also led to significant increases in the expression of Snail mRNA and protein, which mirrored the invasive and migratory potential of these cell lines. These results suggest that PPAR? promotes the aggressive phenotype observed in highly metastatic melanoma cells by up-regulating Snail. PMID:25520859

Ham, Sun Ah; Yoo, Taesik; Hwang, Jung Seok; Kang, Eun Sil; Lee, Won Jin; Paek, Kyung Shin; Park, Chankyu; Kim, Jin-Hoi; Do, Jeong Tae; Lim, Dae-Seog; Seo, Han Geuk

2014-01-01

381

Seasonal dynamics of two mortality-related trematodes using an introduced snail.  

PubMed

Seasonal dynamics of 2 trematode species, Cyathocotyle bushiensis and Sphaeridiotrema globulus, were assessed in relation to life history traits of the parasites and their hosts, as well as abundance of host species and abundance of infective stages. Both of these trematodes are associated with recurrent mortality of migrating waterbirds on the Upper Mississippi River National Wildlife and Fish Refuge. An invasive snail species, Bithynia tentaculata, serves as intermediate host for both trematode species. In total, 2,970 snails were collected at 2 study sites. Prevalence and mean abundance of the 2 trematode species varied among dates and was attributed to several factors, including migration patterns of definitive hosts, snail population dynamics, and seasonal changes in temperature. The surge of new infections of both parasites seems to be due to avian hosts foraging at this site during spring migration. The high prevalence and abundance of metacercariae among the snail population promote mortality among molluscivorous birds by increasing the probability of ingestion of a lethal dose. Additionally, mortality of non-molluscivorous birds can be explained by accidental ingestion of a couple of highly infected snails resulting in a lethal dose. PMID:20049988

Herrmann, Kristin K; Sorensen, Robert E

2009-08-01

382

Adenine nucleotides in snail muscles as one of biomarkers of fluoride toxicity.  

PubMed

The aim of this work was to determine the extent of bioaccumulation of fluorides in tissues of Helix aspersa maxima. The toxicity of fluorides administered orally on the energy balance of the snail's foot was investigated based on measurements of concentrations of adenine nucleotides and their metabolism degradation products. Quantitation of fluoride levels was done in soft tissues (foot, hepatopancreas) and shells of mature snails. Qualitative and quantitative analysis of purine compounds was performed in slices of foot from mature snails. Fluoride concentrations in pulverized shells were measured using an ion-selective electrode. Gas chromatography was used to determine fluoride concentrations in soft tissues (hepatopancreas and foot). Purines were measured in foot muscle slices with high-performance liquid chromatography (HPLC). Fluoride levels in soft tissues of the snail cannot serve as an indicator for biomonitoring purposes as no significant accumulation was observed during exposure to maximum allowable concentrations of fluoride in drinking water. Contrary to this, levels of fluoride in the shell rose significantly with this concentration of fluoride in drinking water. The effect of fluorides on energy metabolism of foot muscle was evidenced by elevated AMP levels, increased adenine nucleotide pool and reduced conversion of ADP to ATP. Exposure to rising F(-) concentrations was accompanied by decreasing values of the adenylate energy charge AEC. Determination of AMP or AEC in foot muscle of exposed snails seems to be a useful indicator of fluoride effects on metabolic activity. PMID:15931426

Rac, Monika; Safranow, Krzysztof; Jakubowska, Katarzyna; Chlubek, Dariusz; Machoy, Zygmunt

2005-06-01

383

A Snail1/Notch1 Signaling Axis Controls Embryonic Vascular Development  

PubMed Central

Notch1-Delta-like 4 (Dll4) signaling controls vascular development by regulating endothelial cell (EC) targets that modulate vessel wall remodeling and arterial-venous specification. The molecular effectors that modulate Notch signaling during vascular development remain largely undefined. Here we demonstrate that the transcriptional repressor, Snail1, acts as a VEGF-induced regulator of Notch1 signaling and Dll4 expression. EC-specific Snail1 loss-of-function conditional knockout mice die in utero with defects in vessel wall remodeling in association with losses in mural cell investment and disruptions in arterial-venous specification. Snail1 loss-of-function conditional knockout embryos further display up-regulated Notch1 signaling and Dll4 expression that is partially reversed by inhibiting ?-secretase activity in vivo with Dll4 identified as a direct target of Snail1-mediated transcriptional repression. These results document a Snail1-Dll4/Notch1 axis that controls embryonic vascular development. PMID:24894949

Wu, Zhao-Qiu; Rowe, R. Grant; Lim, Kim-Chew; Lin, Yongshun; Willis, Amanda; Tang, Yi; Li, Xiao-Yan; Nor, Jacques E; Maillard, Ivan; Weiss, Stephen J

2014-01-01

384

Direct and indirect effects of copper-contaminated sediments on the functions of model freshwater ecosystems.  

PubMed

Copper is acutely toxic to, and directly affects, primary producers and decomposers, which are key players in essential processes such as the nutrient cycle in freshwater ecosystems. Even though the indirect effects of metals (for example effects due to changes in species interactions) may be more common than direct effects, little is known about the indirect effects of copper on primary producers and decomposers. The effects of copper on phytoplankton, macrophytes, periphyton and organic matter decomposition in an outdoor lentic mesocosm facility were assessed, and links between the responses examined. Copper directly decreased macrophyte growth, subsurface organic matter decomposition, and the potential for high phytoplankton Chlorophyll a concentrations. However, periphyton cover and organic matter decomposition on the surface of the sediment were stimulated by the presence of copper. These latter responses were attributed to indirect effects, due to a reduction in grazing pressure from snails, particularly Physa acuta, in the higher copper-contaminated mesocosms. This permitted the growth of periphyton and other heterotrophs, ultimately increasing decomposition at the sediment surface. The present study demonstrates the pronounced influence indirect effects may have on ecological function, findings that may not be observed in traditional laboratory studies (which utilize single species or simplistic communities). PMID:25261958

Gardham, Stephanie; Chariton, Anthony A; Hose, Grant C

2015-01-01

385

Conservation status of freshwater gastropods of Canada and the United States  

USGS Publications Warehouse

This is the first American Fisheries Society conservation assessment of freshwater gastropods (snails) from Canada and the United States by the Gastropod Subcommittee (Endangered Species Committee). This review covers 703 species representing 16 families and 93 genera, of which 67 species are considered extinct, or possibly extinct, 278 are endangered, 102 are threatened, 73 are vulnerable, 157 are currently stable, and 26 species have uncertain taxonomic status. Of the entire fauna, 74% of gastropods are imperiled (vulnerable, threatened, endangered) or extinct, which exceeds imperilment levels in fishes (39%) and crayfishes (48%) but is similar to that of mussels (72%). Comparison of modern to background extinction rates reveals that gastropods have the highest modern extinction rate yet observed, 9,539 times greater than background rates. Gastropods are highly susceptible to habitat loss and degradation, particularly narrow endemics restricted to a single spring or short stream reaches. Compilation of this review was hampered by a paucity of current distributional information and taxonomic uncertainties. Although research on several fronts including basic biology, physiology, conservation strategies, life history, and ecology are needed, systematics and curation of museum collections and databases coupled with comprehensive status surveys (geographic limits, threat identification) are priorities.

Johnson, Paul D.; Bogan, Arthur E.; Brown, Kenneth M.; Burkhead, Noel M.; Cordeiro, James R.; Garner, Jeffrey T.; Hartfield, Paul D.; Lepitzki, Dwayne A.; Mackie, Gerry L.; Pip, Eva; Tarpley, Thomas A.; Tiemann, Jeremy S.; Whelan, Nathan V.; Strong, Ellen E.

2013-01-01

386

Impact of the fungicide carbendazim in freshwater microcosms. II. Zooplankton, primary producers and final conclusions.  

PubMed

Effects of chronic application of the fungicide Derosal(R) (active ingredient carbendazim) were studied in indoor macrophyte-dominated freshwater microcosms. The concentrations (0, 3.3, 33, 100, 330 and 1000 µg/l) were kept at a constant level for 4 weeks. This paper is the second of a series of two; it describes the effects on zooplankton and primary producers and presents an overall discussion. The zooplankton community was negatively affected by the three highest treatment levels (NOEC(community)=33 µg/l). At higher treatment levels Cladocera taxa were completely eliminated, while Copepod numbers were reduced. Rotatoria taxa decreased (Keratella quadrata and Lecane sp.) or increased in abundance (Testudinella parva) at the highest treatment level only. Due to the reduced grazing pressure, the abundance of some phytoplankton taxa and the chlorophyll-a content of the phytoplankton increased at the three highest treatment levels (NOEC(community)=33 µg/l). This effect was not observed for the periphyton, most probably because the reduced grazing pressure was compensated by the increased abundance of some snail species such as Lymnaea stagnalis and Physella acuta. At the end of the experimental period the biomass of the macrophyte Elodea nuttallii was significantly elevated at the two highest treatment levels. It is hypothesised that carbendazim might have caused, directly or indirectly, the removal of pathogene organisms from the macrophyte. PMID:10686330

Van den Brink PJ; Hattink; Bransen; Van Donk E; Brock

2000-03-01

387

Application of Failure Mode and Effect Analysis (FMEA) and Cause and Effect Analysis in Conjunction with ISO 22000 to a Snails (Helix aspersa) Processing Plant; A Case Study  

Microsoft Academic Search

Failure Mode and Effect Analysis (FMEA) has been applied for the risk assessment of snails manufacturing. A tentative approach of FMEA application to the snails industry was attempted in conjunction with ISO 22000.Preliminary Hazard Analysis was used to analzse and predict the occurring failure modes in a food chain system (snails processing plant), based on the functions, characteristics, and\\/or interactions

Ioannis S. Arvanitoyannis; Theodoros H. Varzakas

2009-01-01

388

Global diversity of hairworms (Nematomorpha: Gordiaceae) in freshwater  

Microsoft Academic Search

Freshwater hairworms (Gordiaceae) and marine hairworms (Nectonematoidea) comprise the phylum Nematomorpha. Only the freshwater\\u000a forms are discussed here. While freshwater hairworms develop as parasites of both aquatic and terrestrial arthropods, they\\u000a all enter fresh water to mate, oviposit and produce infective stages (preparasitic larvae). The global species diversity of\\u000a freshwater hairworms based on published descriptions is approximately 326 species and

George Poinar Jr

2008-01-01

389

A Copper Sulfate?Citric Acid Pond Shoreline Treatment to Control the Rams-Horn Snail Planorbella trivolvis  

Microsoft Academic Search

The rams-horn snail Planorbella trivolvis carries at least two important digenetic trematodes that infect propagated fish species in the southeastern United States. These snails are found in fish production ponds, and there are no proven chemical methods for eliminating them that would not also kill the fish. Application of an aqueous solution of 589 g of copper sulfate and 58.9

Andrew J. Mitchell

2002-01-01

390

Fecal bacterial contamination in natural water reservoirs as an indicator of seasonal infection by Opisthorchis viverrini in snail intermediate hosts  

Microsoft Academic Search

Opisthorchis viverrini, a carcinogenic liver fluke, requires Bithynia snails as the first intermediate host, which release cercariae after ingesting fluke eggs from contaminated water. Fecal bacterial contamination and O. viverrini-infected Bithynia snails were investigated in samples collected from natural water reservoirs in Ban Phai, Chonnabot and Muang Districts (Ban Lerngpeuy) in Khon Kaen Province, northeast Thailand, where there is a

Wanlop Kaewkes; Sasithorn Kaewkes; Smarn Tesana; Thewarach Laha; Banchob Sripa

391

Size-fecundity relationships in the land snail Helix aspersa: preliminary results on a form outside the norm  

Microsoft Academic Search

Reproductive traits of the land snail Helix aspersa Müller were investigated under artificial conditions in a breeding population of a giant subspecies from North Africa, namely Helix aspersa maxima. The results were compared with data obtained from experiments conducted under the same experimental with the common form Helix aspersa aspersa from (1) a population from the same snail farm, which

LUC MADEC; ANNIE GUILLER; MARIE-AGNES COUTELLEC-VRETO; CHRISTOPHE DESBUQUOIS

1998-01-01

392

Influence of diets enriched with different vegetable oils on the fatty acid profiles of snail He lix aspersa maxima  

Microsoft Academic Search

The proximate analyses and fatty acid profiles of snail (Helix aspersa maxima) muscle submitted to different feedings with diets enriched with 3% of different vegetable oils (canola, soybean, flaxseed, sunflower, maize and rice) were analysed. The lowest value of lipids was in the snail muscle of the treatment enriched with soybean oil. The main fatty acids detected were palmitic (C16:0),

Maria Cristina Milinsk; Roseli das Graças Padre; Carmino Hayashi; Nilson Evelázio de Souza; Makoto Matsushita

2003-01-01

393

Shell of snail Helix aspersa maxima (Helicidae) as a protection of bioaccumulation toxic sodium fluoride in soft tissue.  

PubMed

The aim of this work was to determine the extent of bioaccumulation of sodium fluorides in tissues of snails under strictly controlled conditions, and also to determine resistance and tolerance to sodium fluoride load in these organisms. The study was performed on snails removed from aestivation. Quantitation of fluoride levels was done in soft tissues (foot, hepatopancreas) and shells of mature snails. Results show that long exposure to sodium fluoride pollution at a low level results in accumulation principally in the soft tissues of the snails. Because of the possibility of fluoride accumulation in the foot, the number of snails used for culinary purposes must be controlled, as it can potentially cause chronic toxemia caused by this trace element. Results also show that the shells of snails offer protection against the bioaccumulation of toxic fluoride in the soft tissue. The Helix aspersa maxima snail is characterised by high resistance and tolerance to fluoride load. Fluoride levels in soft tissues of the snail cannot serve as an indicator for biomonitoring purposes. In contrast, levels in the shell rose significantly with the concentration of fluoride and can be used in biomonitoring of sodium fluoride pollution. PMID:19058550

Ra?, Monika Ewa; Stachowska, Ewa; Machoy, Zygmunt

2005-01-01

394

Dynamics of freshwater plumes: observations and numerical modeling of the wind-forced response and alongshore freshwater transport  

E-print Network

A freshwater plume often forms when a river or an estuary discharges water onto the continental shelf. Freshwater plumes are ubiquitous features of the coastal ocean and usually leave a striking signature in the coastal ...

Fong, Derek Allen

1988-01-01

395

The origin of the salmonid fishes: marine, freshwater... or neither?  

Microsoft Academic Search

The evolutionary origins of the salmonidfishes, whether in freshwater or the sea, havebeen debated for centuries. Early viewsfavoured a group of marine ancestry invadingfreshwaters; more recently, there was a shifttowards a freshwater ancestry, on grounds thata return to freshwater to spawn indicates theancestral biome. Salmonids are widely believedto share an ancient common ancestry with thenorthern hemisphere Osmeridae and southernhemisphere Retropinnidae

R. M. McDowall

2001-01-01

396

Prospects for monitoring freshwater ecosystems towards the 2010 targets  

Microsoft Academic Search

Human activities have severely affected the condition of freshwater ecosystems worldwide. Physical alteration, habitat loss, water withdrawal, pollution, overexploitation and the introduction of non- native species all contribute to the decline in freshwater species. Today, freshwater species are, in general, at higher risk of extinction than those in forests, grasslands and coastal ecosystems. For North America alone, the projected extinction

C. Revenga; I. Campbell; R. Abell; P. de Villiers; M. Bryer

2005-01-01

397

Common Freshwater Fish Parasites Pictorial Guide: Crustaceans1  

E-print Network

FA-115 Common Freshwater Fish Parasites Pictorial Guide: Crustaceans1 Deborah B. Pouder, Eric W of pictorial guides that is designed to assist in the identification of common freshwater fish parasites. The publications included in this series are: · Common Freshwater Fish Parasites Pictorial Guide: Sessile Ciliates

Watson, Craig A.

398

Common Freshwater Fish Parasites Pictorial Guide: Motile Ciliates1  

E-print Network

FA108 Common Freshwater Fish Parasites Pictorial Guide: Motile Ciliates1 Deborah B. Pouder, Eric W of pictorial guides that is designed to assist in the identification of common freshwater fish parasites. The publications included in this series are: · Common Freshwater Fish Parasites Pictorial Guide: Sessile Ciliates

Watson, Craig A.

399

Common Freshwater Fish Parasites Pictorial Guide: Monogeneans1  

E-print Network

FA-111 Common Freshwater Fish Parasites Pictorial Guide: Monogeneans1 Deborah B. Pouder, Eric W of pictorial guides that is designed to assist in the identification of common freshwater fish parasites. The publications included in this series are: · Common Freshwater Fish Parasites Pictorial Guide: Sessile Ciliates

Watson, Craig A.

400

STUDY ABROADFOR MARINE AND FRESHWATER BIOLOGY MAJORS study abroad  

E-print Network

STUDY ABROADFOR MARINE AND FRESHWATER BIOLOGY MAJORS study abroad #12;WHY YOU SHOULD STUDY ABROAD 2 STUDY ABROAD FOR MARINE AND FRESHWATER BIOLOGY MAJORS Study abroad programs provide Marine financial aid? STUDY ABROAD FOR MARINE AND FRESHWATER BIOLOGY MAJORS 3 · How will I get credit

John, Lizy Kurian

401

TIDAL FRESHWATER WETLANDS OF THE MID-ATLANTIC AND  

E-print Network

Chapter 14 TIDAL FRESHWATER WETLANDS OF THE MID-ATLANTIC AND SOUTHEASTERN UNITED STATES James E Publishers, Weikersheim, 2009 Tidal Freshwater Wetlands, edited by Aat Barendregt in the book ,,Tidal Freshwater Wetlands". The copy attached is provided by Margraf Publishers Gmb

Newman, Michael C.

402

Sympatric and allopatric experimental infections of the planorbid snail Gyraulus chinensis with miracidia of Euparyphium albuferensis (Trematoda: Echinostomatidae).  

PubMed

An experimental infection with echinostomatid miracidia in sympatric or 'local' vs. allopatric or 'away' snail combinations, as a model to examine parasite compatibility, was carried out. We employed Euparyphium albuferensis miracidia to infect Gyraulus chinensis snails, from three different natural parks: Albufera (Valencia, Spain); the Ebro Delta (Tarragona, Spain) and Coto de Doñana (Huelva, Spain). Insignificant differences between the three snail strains were noted for the infection rate and the rhythm of daily cercarial production. However, a significantly higher total cercarial production per snail, patent period and life span were observed in local snails. The different infection characteristics in the three G. chinensis strains considered reveal that E. albuferensis miracidia demonstrate local adaptation. PMID:20236558

Muñoz-Antoli, C; Marín, A; Trelis, M; Toledo, R; Esteban, J-G

2010-12-01

403

Hatching of Echinostoma trivolvis miracidia in response to snail host and non-host chemical cues.  

PubMed

Environmental cues are used by many organisms to time life history transitions and can be important for trematode host location. However, while much is understood about how larval trematodes locate hosts, much less is known about the potential role of host cues in the timing of trematode egg development and hatching. We addressed the potential role of host chemical cues in mediating hatching of Echinostoma trivolvis miracidia by comparing hatching in response to cues from the first intermediate host (the snail Planorbella trivolvis), a non-host snail (the snail Goniobasis proxima), and a non-host invertebrate (earthworm, Lumbricus terrestris). We hypothesized that in the presence of cues from their first intermediate host, E. trivolvis would hatch sooner and would be more synchronized than when host cues were absent. However, we found that hatching was unaffected by our cue treatments. In all treatments, hatching uniformly began at 13 days and was nearly evenly spread over the next 3 weeks. PMID:19513751

Belden, Lisa K; Widder, Pamela D; Fischer, Lauren R; Carter, Ashlee B; Wojdak, Jeremy M

2009-09-01

404

Compatibility polymorphism in snail/schistosome interactions: From field to theory to molecular mechanisms  

PubMed Central

Coevolutionary dynamics in host–parasite interactions potentially lead to an arms race that results in compatibility polymorphism. The mechanisms underlying compatibility have remained largely unknown in the interactions between the snail Biomphalaria glabrata and Schistosoma mansoni, one of the agents of human schistosomiasis. This review presents a combination of data obtained from field and laboratory studies arguing in favor of a matching phenotype model to explain compatibility polymorphism. Investigations focused on the molecular determinants of compatibility have revealed two repertoires of polymorphic and/or diversified molecules that have been shown to interact: the parasite antigens S. mansoni polymorphic mucins and the B. glabrata fibrinogen-related proteins immune receptors. We hypothesize their interactions define the compatible/incompatible status of a specific snail/schistosome combination. This line of thought suggests concrete approaches amenable to testing in field-oriented studies attempting to control schistosomiasis by disrupting schistosome–snail compatibility. PMID:21945832

Mitta, G.; Adema, C.M.; Gourbal, B.; Loker, E.S.; Theron, A.

2013-01-01

405

Infectivity of Echinostoma friedi miracidia to different snail species under experimental conditions.  

PubMed

The infectivity of Echinostoma friedi (Trematoda: Echinostomatidae) miracidia was studied experimentally in a range of laboratory-reared snails that coexist in the same natural locality, namely Radix peregra, Lymnaea fuscus, L. truncatula (Lymnaeidae), Gyraulus chinensis, Helisoma duryi (Planorbidae) and Physella acuta (Physidae), and snails from different geographical origins acting naturally or experimentally as intermediate hosts of Schistosoma spp., namely Planorbarius metidjensis (from Málaga, Spain), Biomphalaria glabrata (Guadeloupe), B. alexandrina (Egypt) (Planorbidae), Bulinus cernicus (Mauritius), B. globosus (Zambia), B. natalensis (South Africa) and B. truncatus (Niger) (Bulinidae). Six species of snails were found to be susceptible, with the rate of infection ranging from 0 to 36.7%. The highest infection was detected in R. peregra. The low host specificity of E. friedi might have an epidemiological significance as a requisite for a recent establishment in a new geographical area. PMID:16923279

Muñoz-Antoli, C; Trelis, M; Toledo, R; Esteban, J G

2006-09-01

406

Association between shell morphology of micro-land snails (genus Plectostoma) and their predator's predatory behaviour.  

PubMed

Predator-prey interactions are among the main ecological interactions that shape the diversity of biological form. In many cases, the evolution of the mollusc shell form is presumably driven by predation. However, the adaptive significance of several uncommon, yet striking, shell traits of land snails are still poorly known. These include the distorted coiled "tuba" and the protruded radial ribs that can be found in micro-landsnails of the genus Plectostoma. Here, we experimentally tested whether these shell traits may act as defensive adaptations against predators. We characterised and quantified the possible anti-predation behaviour and shell traits of Plectostoma snails both in terms of their properties and efficiencies in defending against the Atopos slug predatory strategies, namely, shell-apertural entry and shell-drilling. The results showed that Atopos slugs would first attack the snail by shell-apertural entry, and, should this fail, shift to the energetically more costly shell-drilling strategy. We found that the shell tuba of Plectostoma snails is an effective defensive trait against shell-apertural entry attack. None of the snail traits, such as resting behaviour, shell thickness, shell tuba shape, shell rib density and intensity can fully protect the snail from the slug's shell-drilling attack. However, these traits could increase the predation costs to the slug. Further analysis on the shell traits revealed that the lack of effectiveness in these anti-predation shell traits may be caused by a functional trade-off between shell traits under selection of two different predatory strategies. PMID:24749008

Liew, Thor-Seng; Schilthuizen, Menno

2014-01-01

407

The endocrine disrupter effect of atrazine and glyphosate on Biomphalaria alexandrina snails.  

PubMed

Atrazine (AZ) and glyphosate (GL) are herbicides that are widely applied to cereal crops in Egypt. The present study was designed to investigate the response of the snail Biomphalaria alexandrina (Mollusca: Gastropoda) as a bioindicator for endocrine disrupters in terms of steroid levels (testosterone (T) and 17?-estradiol (E)), alteration of microsomal CYP4501B1-like immunoreactivity, total protein (TP) level, and gonadal structure after exposure to sublethal concentrations of AZ or GL for 3 weeks. In order to study the ability of the snails' recuperation, the exposed snails were subjected to a recovery period for 2 weeks. The results showed that the level of T, E, and TP contents were significantly decreased (p ? 0.05) in both AZ- and GL-exposed groups compared with control (unexposed) group. The level of microsomal CYP4501B1-like immunoreactivity increased significantly (p ? 0.05) in GL- and AZ-exposed snails and reach nearly a 50% increase in AZ-exposed group. Histological investigation of the ovotestis showed that AZ and GL caused degenerative changes including azoospermia and oocytes deformation. Interestingly, all the recovered groups did not return back to their normal state. It can be concluded that both herbicides are endocrine disrupters and cause cellular toxicity indicated by the decrease of protein content and the increase in CYP4501B1-like immunoreactivity. This toxicity is irreversible and the snail is not able to recover its normal state. The fluctuation of CYP4501B1 suggests that this vertebrate-like enzyme may be functional also in the snail and may be used as a biomarker for insecticide toxicity. PMID:24215068

Omran, Nahla Elsayed; Salama, Wesam Mohamed

2013-11-01

408

Experimental Quantification of Long Distance Dispersal Potential of Aquatic Snails in the Gut of Migratory Birds  

PubMed Central

Many plant seeds and invertebrates can survive passage through the digestive system of birds, which may lead to long distance dispersal (endozoochory) in case of prolonged retention by moving vectors. Endozoochorous dispersal by waterbirds has nowadays been documented for many aquatic plant seeds, algae and dormant life stages of aquatic invertebrates. Anecdotal information indicates that endozoochory is also possible for fully functional, active aquatic organisms, a phenomenon that we here address experimentally using aquatic snails. We fed four species of aquatic snails to mallards (Anas platyrhynchos), and monitored snail retrieval and survival over time. One of the snail species tested was found to survive passage through the digestive tract of mallards as fully functional adults. Hydrobia (Peringia) ulvae survived up to five hours in the digestive tract. This suggests a maximum potential transport distance of up to 300 km may be possible if these snails are taken by flying birds, although the actual dispersal distance greatly depends on additional factors such as the behavior of the vectors. We put forward that more organisms that acquired traits for survival in stochastic environments such as wetlands, but not specifically adapted for endozoochory, may be sufficiently equipped to successfully pass a bird's digestive system. This may be explained by a digestive trade-off in birds, which maximize their net energy intake rate rather than digestive efficiency, since higher efficiency comes with the cost of prolonged retention times and hence reduces food intake. The resulting lower digestive efficiency allows species like aquatic snails, and potentially other fully functional organisms without obvious dispersal adaptations, to be transported internally. Adopting this view, endozoochorous dispersal may be more common than up to now thought. PMID:22403642

van Leeuwen, Casper H. A.; van der Velde, Gerard; van Lith, Bart; Klaassen, Marcel

2012-01-01

409

Differential Spatial Repositioning of Activated Genes in Biomphalaria glabrata Snails Infected with Schistosoma mansoni  

PubMed Central

Schistosomiasis is an infectious disease infecting mammals as the definitive host and fresh water snails as the intermediate host. Understanding the molecular and biochemical relationship between the causative schistosome parasite and its hosts will be key to understanding and ultimately treating and/or eradicating the disease. There is increasing evidence that pathogens that have co-evolved with their hosts can manipulate their hosts' behaviour at various levels to augment an infection. Bacteria, for example, can induce beneficial chromatin remodelling of the host genome. We have previously shown in vitro that Biomphalaria glabrata embryonic cells co-cultured with schistosome miracidia display genes changing their nuclear location and becoming up-regulated. This also happens in vivo in live intact snails, where early exposure to miracidia also elicits non-random repositioning of genes. We reveal differences in the nuclear repositioning between the response of parasite susceptible snails as compared to resistant snails and with normal or live, attenuated parasites. Interestingly, the stress response gene heat shock protein (Hsp) 70 is only repositioned and then up-regulated in susceptible snails with the normal parasite. This movement and change in gene expression seems to be controlled by the parasite. Other differences in the behaviour of genes support the view that some genes are responding to tissue damage, for example the ferritin genes move and are up-regulated whether the snails are either susceptible or resistant and upon exposure to either normal or attenuated parasite. This is the first time host genome reorganisation has been seen in a parasitic host and only the second time for any pathogen. We believe that the parasite elicits a spatio-epigenetic reorganisation of the host genome to induce favourable gene expression for itself and this might represent a fundamental mechanism present in the human host infected with schistosome cercariae as well as in other host-pathogen relationships. PMID:25211244

Arican-Goktas, Halime D.; Ittiprasert, Wannaporn; Bridger, Joanna M.; Knight, Matty

2014-01-01

410

Mucus trail tracking in a predatory snail: olfactory processing retooled to serve a novel sensory modality  

PubMed Central

Introduction The rosy wolfsnail (Euglandina rosea), a predatory land snail, finds prey snails and potential mates by following their mucus trails. Euglandina have evolved unique, mobile lip extensions that detect mucus and aid in following trails. Currently, little is known of the neural substrates of the trail-following behavior. Methods To investigate the neural correlates of trail following we used tract-tracing experiments in which nerves were backfilled with either nickel-lysine or Lucifer yellow, extracellular recording of spiking neurons in snail procerebra using a multielectrode array, and behavioral assays of trail following and movement toward the source of a conditioned odor. Results The tract-tracing experiments demonstrate that in Euglandina, the nerves carrying mucus signals innervate the same region of the central ganglia as the olfactory nerves, while the electrophysiology studies show that mucus stimulation of the sensory epithelium on the lip extensions alters the frequency and pattern of neural activity in the procerebrum in a manner similar to odor stimulation of the olfactory epithelium on the optic tentacles of another land snail species, Cantareus aspersa (previously known as Helix aspersa). While Euglandina learn to follow trails of novel chemicals that they contact with their lip extensions in one to three trials, these snails proved remarkably resistant to associative learning in the olfactory modality. Even after seven to nine pairings of odorant molecules with food, they showed no orientation toward the conditioned odor. This is in marked contrast to Cantareus snails, which reliably oriented toward conditioned odors after two to three trials. Conclusions The apparent inability of Euglandina to learn to associate food with odors and use odor cues to drive behavior suggests that the capability for sophisticated neural processing of nonvolatile mucus cues detected by the lip extensions has evolved at the expense of processing of odorant molecules detected by the olfactory system. PMID:24653958

Patel, Kinjal; Shaheen, Nagma; Witherspoon, Jessica; Robinson, Natallia; Harrington, Melissa A

2014-01-01

411

Freshwater savings from marine protein consumption  

NASA Astrophysics Data System (ADS)

Marine fisheries provide an essential source of protein for many people around the world. Unlike alternative terrestrial sources of protein, marine fish production requires little to no freshwater inputs. Consuming marine fish protein instead of terrestrial protein therefore represents freshwater savings (equivalent to an avoided water cost) and contributes to a low water footprint diet. These water savings are realized by the producers of alternative protein sources, rather than the consumers of marine protein. This study quantifies freshwater savings from marine fish consumption around the world by estimating the water footprint of replacing marine fish with terrestrial protein based on current consumption patterns. An estimated 7 600 km3 yr-1 of water is used for human food production. Replacing marine protein with terrestrial protein would require an additional 350 km3 yr-1 of water, meaning that marine protein provides current water savings of 4.6%. The importance of these freshwater savings is highly uneven around the globe, with savings ranging from as little as 0 to as much as 50%. The largest savings as a per cent of current water footprints occur in Asia, Oceania, and several coastal African nations. The greatest national water savings from marine fish protein occur in Southeast Asia and the United States. As the human population increases, future water savings from marine fish consumption will be increasingly important to food and water security and depend on sustainable harvest of capture fisheries and low water footprint growth of marine aquaculture.

Gephart, Jessica A.; Pace, Michael L.; D'Odorico, Paolo

2014-01-01

412

Freshwater Biological Traits Database (External Review Draft)  

EPA Science Inventory

This draft report discusses the development of a database of freshwater biological traits. The database combines several existing traits databases into an online format. The database is also augmented with additional traits that are relevant to detecting climate change-related ef...

413

Effects of pollution on freshwater invertebrates  

SciTech Connect

The biological effects of acid rain, chlorination, heavy metals and other forms of pollution on freshwater invertebrates are examined in this review. Several methods for evaluating chronic toxicity to pesticide residues and synthetic fuels components are reviewed. The effects of pollutants is reviewed in detail for cladocera, amphipods, isopods, decapods, aquatic insects, molluscs, worms, and protozoa.(KRM)

Buikema

1982-06-01

414

Toxicity of vanadium to different freshwater organisms  

SciTech Connect

The aim of this study is to determine the acute and subchronic toxicity of vanadium for various species of freshwater fish. The long-term toxicity and the effect of vanadium on the reproduction of Daphnia magna is also evaluated and compared with the toxicity of other metals.

Beusen, J.M.; Neven, B.

1987-08-01

415

The Anguillidae, or the Freshwater Eels  

E-print Network

Kill Single Barrier Multiple Barriers Dams and other barriers affect eel densities... ...andBase.org Tesch, 1977 In contrast with salmons, freshwater eels are catadromous - although not all of them they apparently affect eel growth rates... "BII" was a "barrier intensity index" that we developed. Machut et al

Limburg, Karin E.

416

TOXICITY OF SYNTHETIC PYRETHROIDS TO FRESHWATER INVERTEBRATES  

EPA Science Inventory

This report reviews the laboratory toxicity data on freshwater target and nontarget invertebrate s exposed to pyrethroids and evaluates the state of the data. Early in their development, yrethroids were shown to be highly effective insecticides gainst mosquitoes, blackflies and c...

417

2008 NWFSC Tidal Freshwater Genetics Results  

SciTech Connect

Genetic Analysis of Juvenile Chinook Salmon for inclusion in 'Ecology of Juvenile Salmon in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2008. Annual Report to Bonneville Power Administration, Contract DE-AC05-76RL01830.'

David Teel

2009-05-01

418

Effects of Pollution on Freshwater Invertebrates.  

ERIC Educational Resources Information Center

Presents a literature review of the effects of pollution on freshwater invertebrates, covering publications of 1976-77. Some of the areas covered are: (1) toxicant effects on invertebrates; (2) microcosm and community effects, and (3) biological control of aquatic life. A list of 123 references is also presented. (HM)

Buikema, A. L., Jr.; Herricks, E. E.

1978-01-01

419

NUTRIENT CYCLING BY ANIMALS IN FRESHWATER ECOSYSTEMS  

Microsoft Academic Search

? Abstract Animals are important in nutrient cycling in freshwater ecosystems. Via excretory processes, animals can supply nutrients (nitrogen and phosphorus) at rates comparable to major nutrient sources, and nutrient cycling by animals can sup- port a substantial proportion of the nutrient demands of primary producers. In addition, animals may exert strong impacts on the species composition of primary producers

Michael J. Vanni

420

Microbiological quality of freshwater prawns during storage  

Microsoft Academic Search

Microbiological quality analysis of freshwater prawns from three sampling sites in Peninsular Malaysia viz: Site 1- Kg. Jumbang, Negri Sembilan; Site 2- Kg. Cangkat Tin, Perak and Site 3- Kg. Cenderiang, Perak for total mesophilic and psychrophilic aerobic counts, proteolytic bacterial counts, histamine producing bacteria, cadaverine producing bacteria and putrescine producing bacteria in the prawns and pond water for the

Abu Bakar; M. Basri

2008-01-01

421

Seasonal influences on freshwater fisheries sampling data  

Microsoft Academic Search

Fisheries managers often assess fish populations using catch per unit effort (CPUE), size and age structure, growth, and condition. For many freshwater fishes and common sampling gears, CPUE, size and age structure, and condition are highest in the spring and fall, while growth commonly is fastest during the summer growing season. However, there are exceptions to these general trends, especially

Kevin L. Pope; David W. Willis

1996-01-01

422

Ecological Impacts of Nonnative Freshwater Fishes  

Microsoft Academic Search

There is a long history of introduction of non-native fishes in fresh waters and the introduction rate has accelerated greatly over time. Although not all introduced fishes have appreciable effects on their new ecosystems, many exert significant ecological, evolutionary, and economic impacts. For researchers, managers, and policy makers interested in conserving freshwater diversity, understanding the magnitude and array of potential

Julien Cucherousset; Julian D. Olden

2011-01-01

423

The biogeochemistry of nitrogen in freshwater wetlands  

Microsoft Academic Search

The biogeochemistry of N in freshwater wetlands is complicated by vegetation characteristics that range from annual herbs to perennial woodlands; by hydrologic characteristics that range from closed, precipitation-driven to tidal, riverine wetlands; and by the diversity of the nitrogen cycle itself. It is clear that sediments are the single largest pool of nitrogen in wetland ecosystems (100's to 1000's g

William B. Bowden

1987-01-01

424

Snail control in urban sites in Brazil with slow-release hexabutyldistannoxane and pentachlorophenol*  

PubMed Central

Slow release formulations of hexabutyldistannoxane (TBTO) and pentachlorophenol (PCP) were tested for the control of Biomphalaria tenagophila in 52 urban sites in Rio de Janeiro. TBTO acted faster and lasted longer than PCP and at 15 g/m2 it eliminated snails from 76% of the treated sites for 1 year. Water pollution and rate of flow had no significant influence on the molluscicidal properties of either compound, but alkalinity lowered the activity of TBTO. Failure to control snail populations was due mainly to human interference and to the non-treatment of adjacent breeding sites that were temporarily dry and therefore overlooked. PMID:1088356

Toledo, J. V.; Da Silva, C. S. Monteiro; Bulhões, M. S.; Leme, L. A. Paes; Netto, J. A. Da Silva; Gilbert, B.

1976-01-01

425

Inhibition kinetics of certain organophosphorus and carbamate pesticides on acetylcholinesterase from the snail Lymnaea acuminata.  

PubMed

k2, Kd and ki, for 2 organophosphorus (Phorate and Formothion) and 2 carbamate pesticides (Mexacarbate and Carbaryl) using acetylcholinesterase present in homogenates of the nervous tissue of the snail Lymnaea acuminata, were determined. Calculation of zero time velocities demonstrated that even in their P-S form the organophosphate compounds inhibited snail acetylcholinesterase. The kinetic constants of the 2 carbamates have been explained on the basis of their structure. The toxicity of the 4 pesticides has been explained on the basis of their kinetic constants. PMID:6658844

Singh, D K; Agarwal, R A

1983-12-01

426

The life cycle of Echinostoma bolschewense (Kotova, 1939) (Trematoda: Echinostomatidae).  

PubMed

The life cycle of E. bolschewense, the species with 37 collar spines and closely related to E. revolutum, was experimentally studied. The following developmental stages are described: mother and daughter rediae, cercaria, metacercaria, and adult. The freshwater prosobranchiate snail Viviparus contectus was found to be the first intermediate host in nature. Under experimental conditions, the miracidia developed in V. contectus. They did not, however, penetrate into Bithynia tentaculata or into any of the pulmonate snails tested. The cercariae encysted in various Prosobranchia and Pulmonata. Adult worms were commonly obtained from hamsters (Mesocricetus auratus) and only exceptionally from chickens (Gallus gallus f. dom.). The species studied is considered to be conspecific with Cercaria bolschewensis described by Kotova (1939). PMID:1937273

Nasincová, V

1991-01-01

427

Schistosoma haematobium detection in snails by DraI PCR and Sh110/Sm-Sl PCR: further evidence of the interruption of schistosomiasis transmission in Morocco  

PubMed Central

Background This is the first study in Morocco to estimate snail infection rates at the last historic transmission sites of schistosomiasis, known to be free from new infection among humans since 2004. Screening of large numbers of snails for infection is one way to confirm that Schistosoma haematobium transmission has stopped and does not resurge. Methods A total of 2703 Bulinus truncatus snails were collected from 24 snail habitats in five provinces of Morocco: Errachidia, El Kelaa des Sraghna, Tata, Beni Mellal, and Chtouka Ait Baha. All visible snails were collected with a scoop net or by hand. We used waders and gloves as simple precautions. Snails were morphologically identified according to Moroccan Health Ministry guide of schistosomiasis (1982). All snails were analyzed in pools by molecular tool, using primers from the newly identified repeated DNA sequence, termed DraI, in the S. haematobium group. To distinguish S. bovis and S. haematobium, the snails were analyzed by Sh110/Sm-Sl PCR that was specific of S. haematobium. Results The results showed that snails from Errachidia, Chtouka Ait Baha, sector of Agoujgal in Tata and sector of Mbarkiya in El kelaa des Sraghna were negative for DraI PCR; but, snails from remaining snail habitats of El Kelaa des Sraghna, Tata and Beni Mellal were positive. This led to suggest the presence of circulating schistosome species (S. haematobium, S. bovis or others) within these positive snail habitats. Subsequently, confirmation with S. haematobium species specific molecular assay, Sh110/Sm-Sl PCR, showed that none of the collected snails were infected by S. haematobium in all historic endemic areas. Conclusion The absence of S. haematobium infection in snails supports the argument of S. haematobium transmission interruption in Morocco. PMID:24962624

2014-01-01

428

HMGA2 and Smads Co-regulate SNAIL1 Expression during Induction of Epithelial-to-Mesenchymal Transition*S?  

PubMed Central

Epithelial-mesenchymal transition (EMT) is important during embryonic cell layer movement and tumor cell invasiveness. EMT converts adherent epithelial cells to motile mesenchymal cells, favoring metastasis in the context of cancer progression. Transforming growth factor-? (TGF-?) triggers EMT via intracellular Smad transducers and other signaling proteins. We previously reported that the high mobility group A2 (HMGA2) gene is required for TGF-? to elicit EMT in mammary epithelial cells. In the present study we investigated the molecular mechanisms by which HMGA2 induces EMT. We found that HMGA2 regulates expression of many important repressors of E-cadherin. Among these, we analyzed in detail the zinc-finger transcription factor SNAIL1, which plays key roles in tumor progression and EMT. We demonstrate that HMGA2 directly binds to the SNAIL1 promoter and acts as a transcriptional regulator of SNAIL1 expression. Furthermore, we observed that HMGA2 cooperates with the TGF-?/Smad pathway in regulating SNAIL1 gene expression. The mechanism behind this cooperation involves physical interaction between these factors, leading to an increased binding of Smads to the SNAIL1 promoter. SNAIL1 seems to play the role of a master effector downstream of HMGA2 for induction of EMT, as SNAIL1 knock-down partially reverts HMGA2-induced loss of epithelial differentiation. The data propose that HMGA2 acts in a gene-specific manner to orchestrate the transcriptional network necessary for the EMT program. PMID:18832382

Thuault, Sylvie; Tan, E-Jean; Peinado, Hector; Cano, Amparo; Heldin, Carl-Henrik; Moustakas, Aristidis

2008-01-01

429

Biotic interactions modify the transfer of cesium-137 in a soil-earthworm-plant-snail food web.  

PubMed

The present study investigated the possible influence of the earthworm Aporrectodea tuberculata on the transfer of cesium-137 ((137)Cs) from a contaminated (130 Bq/kg) deciduous forest soil to the lettuce Lactuca sativa and to the snail Cantareus aspersus (formerly Helix aspersa) in two laboratory experiments. In the first experiment, the International Organization for Standardization 15952 test was used to expose snails for five weeks to contaminated soil with or without earthworms. In these conditions, the presence of earthworms caused a two- to threefold increase in (137)Cs concentrations in snails. Transfer was low in earthworms as well as in snails, with transfer factors (TFs) lower than 3.7 x 10(-2). Activity concentrations were higher in earthworms (2.8- 4.8 Bq/kg dry mass) than in snails (<1.5 Bq/kg). In the second experiment, microcosms were used to determine the contribution of soil and lettuce in the accumulation of (137)Cs in snails. Results suggest that the contribution of lettuce and soil is 80 and 20%, respectively. Microcosms also were used to study the influence of earthworms on (137)Cs accumulation in snail tissues in the most ecologically relevant treatment (soil-earthworm-plant-snail food web). In this case, soil-to-plant transfer was high, with a TF of 0.8, and was not significantly modified by earthworms. Conversely, soil-to-snail transfer was lower (TF, approximately 0.1) but was significantly increased in presence of earthworms. Dose rates were determined in the microcosm study with the EDEN (elementary dose evaluation for natural environment) model. Dose rates were lower than 5.5 x 10(-4) mGy/d, far from values considered to have effects on terrestrial organisms (1 mGy/d). PMID:18266477

Fritsch, Clémentine; Scheifler, Renaud; Beaugelin-Seiller, Karine; Hubert, Philippe; Coeurdassier, Michaël; de Vaufleury, Annette; Badot, Pierre-Marie

2008-08-01

430

New insight in lymnaeid snails (Mollusca, Gastropoda) as intermediate hosts of Fasciola hepatica (Trematoda, Digenea) in Belgium and Luxembourg  

PubMed Central

Background The present study aims to assess the epidemiological role of different lymnaeid snails as intermediate hosts of the liver fluke Fasciola hepatica in Belgium and Luxembourg. Methods During summer 2008, 7103 lymnaeid snails were collected from 125 ponds distributed in 5 clusters each including 25 ponds. Each cluster was located in a different biogeographic area of Belgium and Luxembourg. In addition, snails were also collected in sixteen other biotopes considered as temporary wet areas. These snails were identified as Galba truncatula (n?=?2474) (the main intermediate host of F. hepatica in Europe) and Radix sp. (n?=?4629). Moreover, several biological and non-biological variables were also recorded from the different biotopes. DNA was extracted from each snail collected using Chelex® technique. DNA samples were screened through a multiplex PCR that amplifies lymnaeid internal transcribed spacer 2 gene sequences (500–600 bp) (acting as an internal control) and a 124 bp fragment of repetitive DNA from Fasciola sp. Results Lymnaeid snails were found in 75 biotopes (53.2%). Thirty individuals of G. truncatula (1.31%) and 7 of Radix sp. (0.16%) were found to be positive for Fasciola sp. The seven positive Radix sp. snails all belonged to the species R. balthica (Linnaeus, 1758). Classification and regression tree analysis were performed in order to better understand links and relative importance of the different recorded factors. One of the best explanatory variables for the presence/absence of the different snail species seems to be the geographic location, whereas for the infection status of the snails no obvious relationship was linked to the presence of cattle. Conclusions Epidemiological implications of these findings and particularly the role of R. balthica as an alternative intermediate host in Belgium and Luxembourg were discussed. PMID:24524623

2014-01-01

431

Population Genetics and the Effects of a Severe Bottleneck in an Ex Situ Population of Critically Endangered Hawaiian Tree Snails  

PubMed Central

As wild populations decline, ex situ propagation provides a potential bank of genetic diversity and a hedge against extinction. These programs are unlikely to succeed if captive populations do not recover from the severe bottleneck imposed when they are founded with a limited number of individuals from remnant populations. In small captive populations allelic richness may be lost due to genetic drift, leading to a decline in fitness. Wild populations of the Hawaiian tree snail Achatinella lila, a hermaphroditic snail with a long life history, have declined precipitously due to introduced predators and other human impacts. A captive population initially thrived after its founding with seven snails, exceeding 600 captive individuals in 2009, but drastically declined in the last five years. Measures of fitness were examined from 2,018 captive snails that died between 1998 and 2012, and compared with genotypic data for six microsatellite loci from a subset of these deceased snails (N?=?335), as well as live captive snails (N?=?198) and wild snails (N?=?92). Surprisingly, the inbreeding coefficient (Fis) declined over time in the captive population, and is now approaching values observed in the 2013 wild population, despite a significant decrease in allelic richness. However, adult annual survival and fecundity significantly declined in the second generation. These measures of fitness were positively correlated with heterozygosity. Snails with higher measures of heterozygosity had more offspring, and third generation offspring with higher measures of heterozygosity were more likely to reach maturity. These results highlight the importance of maintaining genetic diversity in captive populations, particularly those initiated with a small number of individuals from wild remnant populations. Genetic rescue may allow for an increase in genetic diversity in the captive population, as measures of heterozygosity and rarified allelic richness were higher in wild tree snails. PMID:25470182

Price, Melissa R.; Hadfield, Michael G.

2014-01-01

432

Evaluating Pond Shoreline Treatments of Slurried Hydrated Lime for Reducing Marsh Rams-Horn Snail Populations  

Microsoft Academic Search

Trematode parasites can cause massive infections in commercially raised fish. The most promising approach for the control of these infections is the reduction or elimination of snails that serve as vectors for the trematodes. A recent approach, the application of high concentrations of slurried hydrated lime (SHL) or copper sulfate pentahydrate (CSP) along pond margins (shoreline treatment), has shown promise

Andrew J. Mitchell; Scott Snyder; David J. Wise; Charles C. Mischke

2007-01-01

433

Sensitive and species-specific detection of Clonorchis sinensis by PCR in infected snails and fishes  

Microsoft Academic Search

In the present study, PCR procedures have been established for a rapid and easy preparation of DNA of parasite stages from\\u000a the intermediate hosts, i.e. sporocysts and rediae in snails and metacercariae in fishes. Primers have been developed, which\\u000a enable a highly sensitive and species-specific detection of Clonorchis sinensis.

Boris Müller; Jürgen Schmidt; Heinz Mehlhorn

2007-01-01

434

The toxic activities of Arisaema erubescens and Nerium indicum mixed with Streptomycete against snails.  

PubMed

The comparative molluscicidal activities of Arisaema erubescens tuber extracts and Nerium indicum leaf extracts mixed with Streptomycete violacerruber dilution (SD) against the snail Oncomlania hupensis and the responses of the isozymes, esterase (EST) and superoxide dismutase (SOD) to the A. erubescens extracts and the mixtures were investigated. The molluscicidal activity of A. erubescens water extracts mixed with S. violacerruber dilution was 4-5 times higher than a single A. erubescens or S. violacerruber dilution after 24-h exposure, and is also higher than that of N. indicum leaf water extracts mixed with S. violacerruber dilution. At the end of exposure to the N-butanol extracts of A. erubescens tubers (NEAT), the EST activity in snail liver decreased and some enzyme bands (EST 1 and EST 3 in exposure to NEAT) disappeared but the activities of SOD 1 increased. The effect was more obvious in mixture treatment than in single NEAT or SD treatment. The results indicated that molluscicidal activities of plant and microorganism could be more effective than single plant. The decline of the detoxic ability in snail liver cells could be the reason of the snail dying. PMID:21783953

Zhang, Yi; Ke, Wenshan; Yang, Jinglian; Ma, Anning; Yu, Zhensen

2009-03-01

435

Accumulation of cadmium and copper by the terrestrial snail Arianta arbustorum L.: kinetics and budgets  

Microsoft Academic Search

Specimens of the terrestrial gastropod Arianta arbustorum were fed on cadmium- or copper-enriched agar plates with the aim of performing an input\\/output analysis and of studying the distribution of these metals in several organs of the snails. After a feeding period of 20 days about 45% of cadmium were lost. 36% accumulated in the hepatopancreas, where a cadmium concentration of

Burkhard Berger; Reinhard Dallinger

1989-01-01

436

Metapopulation genetic structure and migration pathways in the land snail Helix aspersa: influence of landscape heterogeneity  

Microsoft Academic Search

The spatial genetic structuring of the land snail Helix aspersa was investigated for 32 colonies within an intensive agricultural area, the polders of the Bay of Mont-Saint-Michel (France). Given the habitat patchiness and envi- ronmental instability, the setting of H. aspersa colonies meets the broader view of a metapopulation structure. The identification of extrinsic barriers to migration and their impact

Jean-François Arnaud

2003-01-01

437

Effect of snails (Elimia clavaeformis) on phosphorus cycling in stream periphyton and leaf detritus communities  

SciTech Connect

In this study, the author examined the effect of grazing on phosphorus cycling in stream periphyton and leaf detritus communities using the snail Elimia clavaeformis. Phosphorus cycling fluxes and turnover rates were measured in a laboratory and in a natural stream, respectively, using radioactive tracer techniques.

Jay, E.A. [North Carolina Univ., Chapel Hill, NC (United States)

1993-10-01

438

Compatibility of Ugandan Schistosoma mansoni isolates with Biomphalaria snail species from Lake Albert and Lake Victoria.  

PubMed

In order to investigate the capacity of being intermediate host for Schistosoma mansoni, the Ugandan F1 generation of Biomphalaria snail species that were laboratory-bred from parent populations originally collected from either Lake Victoria or Lake Albert was challenged with sympatric and non-sympatric S. mansoni isolates. After a prepatent period of 20 days, a daily 10-hourly snail shedding for cercariae was done to determine the infection rate, cercarial production per hour and survival period of infected snails. The study suggests that when parasite strains from a different geographical origin is used for infection, survival of infected snails increase, leading to an increased transmission potential. Although earlier literature had indicated that the Lake Victoria Biomphalaria sudanica is refractory to S. mansoni, we showed that all Ugandan Biomphalaria spp., including B. sudanica from all locations, were highly susceptible to the S. mansoni isolates. Thus if B. choanomphala, which is an efficient intermediate host in Lake Victoria, is given an opportunity to occupy Lake Albert, it will most likely be compatible with the Albertine S. mansoni p