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1

An Evaluation of the Interactions Between Freshwater Pulmonate Snail Hosts of Human Schistosomes and Macrophytes  

Microsoft Academic Search

An account is given of a laboratory investigation designed to evaluate the extent to which the freshwater pulmonate snail Biomphalaria glabrata (Say) can utilize various species of aquatic plants, mainly macrophytes, when presented in the following forms over different time scales: (i) normal plants; (ii) dried plant material; (iii) homogenized plant material in calcium alginate matrices; (iv) water-soluble filtrates of

J. D. Thomas

1987-01-01

2

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

PubMed

The freshwater pulmonate snail, Lymnaea stagnalis, is the most sensitive aquatic organism tested to date for Pb with an estimated EC20 for juvenile snail growth of 3 ?g l?¹. A previous study supported the hypothesis that this hypersensitivity to Pb was due to an extremely high Ca²? uptake rate needed to support shell formation. The current study sought to build upon this working hypothesis and develop a mechanistic predictive model for inhibition of snail growth as a function of Pb exposure. Initial experiments confirmed previous predictions that juvenile snails have net Ca²? uptake rates of 7000-8000 nmol g?¹ h?¹, approximately 100-fold higher than observed in a typical freshwater fish. However, an initial time course study revealed that the onset of growth inhibition occurs at least 4d prior to inhibition of net Ca²? flux in Pb-exposed snails indicating the latter is not the primary mechanism of action. Qualitative observations during this experiment indicated snail feeding was inhibited in a dose-dependent manner. A subsequent experiment demonstrated that when food is withheld from snails for even 24 h, net Ca²? uptake is significantly (?50%) reduced. A second time course study demonstrated quantitatively that snail feeding is inhibited by Pb exposure by up to 98% at relatively high Pb concentrations (57 ?g l?¹) but no inhibition was observed at ? 10 ?g l?¹ Pb indicating feeding inhibition is not causing observed growth effects at concentrations approximating the EC20 of 3 ?g l?¹ Pb. A final experiment testing whether Pb-induced growth effects are related to inhibition of carbonic anhydrase activity in the snail mantle also failed to demonstrate an effect. We conclude that while both feeding and net Ca²? uptake in snails are affected by Pb exposure, they appear to be secondary effects. The primary mechanism of action explaining L. stagnalis hypersensitivity to Pb remains to be identified. PMID:22172541

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

2011-11-23

3

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

2011-06-23

4

Sensitivity of freshwater pulmonate snails, Lymnaea luteola L., to heavy metals  

Microsoft Academic Search

The current alarm of the impacts of metal pollution on living organisms has received much attention with the tragedy of Minimata and later Niigata, in Japan. Although there has been a great deal of the concern about the acute and chronic toxicities of heavy metals to freshwater fishes and crustaceans but little information is available on the effects of heavy

B. S. Khangarot; P. K. Ray

1988-01-01

5

Additions to the Pulmonate Snails of Oklahoma (With Notes on Anatomical Techniques)  

Microsoft Academic Search

bottom. Using a common large pulmonate snail, a few trial experiments in dissection will soon permit one to devise a satisfactory method. If material is abundant, identifications should be based on the dissection of many specimens. Living snails to be dissected may be drowned or fixed for several minutes in boiling water, both methods being good for reo vealing particular

GLENN R. WEBB

6

Ecology of freshwater snails in south-western Nigeria. I: Distribution and habitat preferences  

Microsoft Academic Search

Dry and rainy season investigations of diverse freshwater habitats in south-western Nigeria revealed fourteen species of snail comprised of nine pulmonates: Biomphalaria pfeifferi Krauss, Bulinus globosus Morelet, Bulinus rohlfsi Clessin, Lymnaea natalensis Krauss, Physa ( ˜ Aplexa) waterloti Germain, Bulinus forskali Ehrenberg, Gyraulus costulatus Krauss, Ferrissia sp, Segmentorbis sp. and five prosobranchs namely, Lanistes libycus Morelet, Lanistes ovum Peters, Pila

G. T. Ndifon; F. M. A. Ukoli

1989-01-01

7

Reduction of growth and haemolymph Ca levels in the freshwater snail Lymnaea stagnalis chronically exposed to cobalt  

Microsoft Academic Search

The ecological risk assessment and the development of water-quality criteria for Co are currently still hampered by insufficient knowledge about the toxicity of Co to freshwater organisms. A relevant group of organisms, for which no toxicity data with Co are available, is the class of the herbivorous pulmonate freshwater snails, which fulfil a pivotal role in the consumption and decomposition

Karel A. C. De Schamphelaere; Joris M. Koene; Dagobert G. Heijerick; Colin R. Janssen

2008-01-01

8

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

Microsoft Academic Search

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

A. A. Zotin; N. D. Ozernyuk

2002-01-01

9

Freshwater snails of Oman, South Eastern Arabia  

Microsoft Academic Search

A systematic account is given of the extant freshwater snail fauna of Oman, based on recent collections made in Dhofar and in the northern mountainous areas. Also included are certain species found in brackish coastal localities. A total of 8 freshwater species is regarded as belonging to the fauna of normal freshwater; 7 have been found alive (Thiara scabra, Melanoides

D. S. Brown; M. D. Gallagher

1985-01-01

10

Development of 10 microsatellite loci in the pulmonate snail Biomphalaria kuhniana (Mollusca, Gastropoda)  

Microsoft Academic Search

We characterized 10 variable microsatellite loci in the freshwater snail Biomphalaria kuhniana, as well as conditions for multiplexing and co-loading sets of loci. Two to five alleles were detected per locus over the two studied populations in Venezuela. High inbreeding coefficients suggest high selfing rates. Cross-species amplification provided some variability at eight and three loci in the other species belonging

VIRGINIE DUPUY; ANTOINE NICOT; PHILIPPE JARNE; PATRICE DAVID

2009-01-01

11

Effects of Temperature on Growth and Reproduction of Aquatic Snails.  

National Technical Information Service (NTIS)

The effects of temperature on the following freshwater snails were studied: Lymnaea stagnalis, L. emarginata, Helisoma trivolvis, H. anceps, H. campanulatum and Physa gyrina -- all pulmonate 'pond' snails; one gill-breathing operculate (Amnicola limosa); ...

H. van der Schalie E. G. Berry D. I. Mount

1973-01-01

12

Populations of the European freshwater pulmonate Physa acuta are not reproductively isolated from American Physa heterostropha or Physa integra  

Microsoft Academic Search

It has long been speculated that Physa ucuta, a pulmonate snail widespread and invasive in fresh waters of the old world, may have originated in North America. But thc identification of a new-world cognate has been complicated by the confused systematics and taxonomy of the Physidae in America. More than 40 species of physids are currently recognized in the United

Robert T. Dillon; Amy R. Wethington; J. Matthew Rhett; Thomas P. Smith

2005-01-01

13

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

PubMed Central

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

Mandahl-Barth, G.

1962-01-01

14

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

Microsoft Academic Search

Background  Factors and processes shaping the population structure and spatial distribution of genetic diversity across a species' distribution\\u000a range are important in determining the range limits. We comprehensively analysed the influence of recurrent and historic factors\\u000a and processes on the population genetic structure, mating system and the distribution of genetic variability of the pulmonate\\u000a freshwater snail Radix balthica. This analysis was

Markus Pfenninger; Moritz Salinger; Timm Haun; Barbara Feldmeyer

2011-01-01

15

Biological control and invading freshwater snails.A case study  

Microsoft Academic Search

Introductions of four species of freshwater snails occurred between 1972 and 1996 onto Guadeloupe Island. Two of them, Melanoides tuberculata and Marisa cornuarietis, were subsequently used as biological control agents against Biomphalaria glabrata, the snail intermediate host of intestinal schistosomiasis. In 1996, a general survey was carried out in 134 sites which had already been investigated in 1972. The total

Jean-Pierre Pointier; David Augustin

1999-01-01

16

Invertebrate host-parasite relationships: convergent evolution of a tropomyosin epitope between Schistosoma sp., Fasciola hepatica, and certain pulmonate snails.  

PubMed

Monoclonal antibodies (mAb) directed against Schistosoma mansoni tropomyosin isoform, SMTM (Xu et al. Experimental Parasitology 69, 373-392, 1989), were used to test for cross-reactivity with Biomphalaria glabrata antigens. One mAb (1F10) recognized antigens of 39, 41, and 80 kDa in a snail head/foot antigen preparation but not a hepatopancreas antigen preparation. Another mAb (1C1) cross-reacted with a 39-kDa antigen in the head/foot extract but not in the hepatopancreas extract. Epitope mapping revealed the 1F10 epitope to be between amino acids 135 and 188 of both Bg39 (Dissous et al. Molecular and Biochemical Parasitology 43, 245-256, 1990) and BgTMII (Weston and Kemp, Experimental Parasitology 76, 358-370, 1993), while the 1C1 epitope was located between amino acids 189 and 213 of BgTMII. Various invertebrate species, including members from Trematoda, Pulmonata, Annelida, and Arthropoda, were tested for cross-reactivity with the monoclonal antibodies. While the 1F10 mAb displayed broad invertebrate cross-reactivity, the 1C1 mAb cross-reactivity was restricted to schistosomes, F. hepatica, and the pulmonate snails B. glabrata and Physa sp. PMID:7512930

Weston, D; Allen, B; Thakur, A; LoVerde, P T; Kemp, W M

1994-05-01

17

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.

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

2009-01-01

18

Food Preference and Reproductive Plasticity in an Invasive Freshwater Snail  

Microsoft Academic Search

The freshwater apple snail Pomacea canaliculata has become a major crop pest in southeast Asia and Hawai'i and threatens natural wetland habitats in these regions and elsewhere. Deliberately introduced as a potential human food resource, it has also been proposed as a possible biocontrol agent against aquatic weeds. Various factors may facilitate its rapid invasion of new areas; we focus

Lori Lach; David K. Britton; Rebecca J. Rundell; Robert H. Cowie

2000-01-01

19

Food preference and reproductive plasticity in an invasive freshwater snail  

Microsoft Academic Search

The freshwater apple snail Pomacea canaliculatahas become a major crop pest in southeast Asia and Hawai'i and threatens natural wetland habitats in these regions and elsewhere. Deliberately introduced as a potential human food resource, it has also been proposed as a possible biocontrol agent against aquatic weeds. Various factors may facilitate its rapid invasion of new areas; we focus on

Lori Lach; David K. Britton; Rebecca J. Rundell; Robert H. Cowie

2000-01-01

20

Snails as Biomonitors of Oil-Spill and Bioremediation Strategies  

Microsoft Academic Search

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

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

2002-01-01

21

Influence of Age and Body Size on Alarm Responses in a Freshwater Snail Pomacea canaliculata  

Microsoft Academic Search

A hypothesis that size selection of prey by predators elicits size-specific responses from prey was examined. Freshwater snails, Pomacea canaliculata, ages 1, 3, 7, 15, 30, or 60 days, were given an extract of 3-day-old snails, and 3-day-old snails were given extracts of snails of the other ages or eggs. Snails 15 days or younger crawled out of the water

Katsuya Ichinose

2002-01-01

22

Heavy metal concentrations in common freshwater snails of Azraq Oasis, Jordan  

Microsoft Academic Search

Heavy metal concentrations in three freshwater snails, an aquatic plant, sediment, and water from Azraq Oasis pools in the Jordanian desert were measured by atomic absorption spectrophotometry. There were significant differences in metal accumulation among snail species. These snails are ranked according to their metal accumulation capacity in the order: Melanoides tuberculata > Melanopsis praemorsa > Theodoxus jordani. Although there

Khaled M. Swaileh; Mohamed N. Mesmar; Naim S. Ismail

1994-01-01

23

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

PubMed

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

Yadav, Ram P; Singh, Ajay

24

Biological control and invading freshwater snails. A case study.  

PubMed

Introductions of four species of freshwater snails occurred between 1972 and 1996 onto Guadeloupe Island. Two of them, Melanoides tuberculata and Marisa cornuarietis, were subsequently used as biological control agents against Biomphalaria glabrata, the snail intermediate host of intestinal schistosomiasis. In 1996, a general survey was carried out in 134 sites which had already been investigated in 1972. The total number of mollusc species had increased from 19 to 21. Site numbers housing B. glabrata and two other species had strongly declined. This decline may be mainly attributed to a competitive displacement by M. tuberculata and M. cornuarietis as illustrated by several biological control programmes. There were no changes in the remainder of the malacological fauna. PMID:10656149

Pointier, J P; Augustin, D

1999-12-01

25

Multiple paternity in the freshwater snail, Potamopyrgus antipodarum  

PubMed Central

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

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

2012-01-01

26

Environment-dependent inbreeding depression in a hermaphroditic freshwater snail.  

PubMed

Inbreeding depression was simultaneously studied under contrasted environments, laboratory and natural conditions, using individuals originating from 14 families of the freshwater snail Physa acuta. Both survival and growth of juveniles showed inbreeding depression under laboratory conditions. The same fitness components were monitored with mature snails either kept under laboratory conditions or released at a natural site and analysed using capture-mark-recapture models. Genetic composition of both samples was similar. Inbreeding depression on survival was highest in the laboratory while strong outbreeding depression was revealed in the field. Thus inbreeding depression may not be always higher under natural conditions, at the opposite of what is commonly assumed. We suggest that inbreeding depression is dependent on metabolic requirements imposed by the environment. Other evidences showing that inbreeding depression is environment-dependent are reviewed. We conclude that genetic models should include both genetic and environmental variance in inbreeding depression for studying mating system evolution. PMID:14640413

Henry, P Y; Pradel, R; Jarne, P

2003-11-01

27

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

PubMed

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

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

2013-05-01

28

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

Microsoft Academic Search

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

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

2009-01-01

29

Freshwater snails in Asser region, Saudi Arabia with special refernce to the zoonotic trematode.  

PubMed

The present study gave information about the recent distribution of freshwater snails in Asser region, and the current status of trematode infection specially schistosomiasis within the snails. Fifteen localities were visited from Septeinber 2007 to December 2008 and the collected snails were examined for the presence of trematode infection. Seven species of snails were collected: Biomphalaria arabica, Bulinus truncatus, Bulinus beccari, Physa acuta, Lymnaea palustris, Lymnaea arabica and Melanoides tuberculata. The parasitological examination revealed none trematode immature stages. PMID:19795761

Bin Dajem, Saad M

2009-08-01

30

Clonal diversity driven by parasitism in a freshwater snail.  

PubMed

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

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

2013-10-01

31

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

Microsoft Academic Search

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

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

32

Invading freshwater snails and biological control in Martinique Island, French West Indies  

Microsoft Academic Search

Eight alien freshwater snail species were introduced into Martinique Island during the last 50 years. The introduced snails include four planorbids (Biomphalaria straminea, Helisoma duryi, Amerianna carinata and Gyraulus sp.), three thiarids (Melanoides tuberculata, M. amabilis and Tarebia granifera) and one ampullarid (Marisa cornuarietis). Four of these species rapidly colonized the whole Martinican hydrographic system whereas the other four remained

Jean-Pierre Pointier

2001-01-01

33

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

34

A tetraploid freshwater snail (Planorbidae: Bulinus) in the highlands of Kenya  

Microsoft Academic Search

Several levels of polyploidy are known in freshwater snails belonging to the Bulinus truncatus\\/tropicus complex. All are present in the highlands of Ethiopia, but only the tetraploid B. truncatus has been recorded from Kenya, living in the western lowlands. Observations are reported here on the chromosome number, shell, internal organs and egg-proteins of snails from 26 localities in the highlands

D. S. Brown

1976-01-01

35

Effectors of metabolic depression in an estivating pulmonate snail ( Helix aspersa ): whole animal and in vitro tissue studies  

Microsoft Academic Search

We have examined metabolic depression in the land snail (Helix aspersa) during estivation, and have developed a tissue model of metabolic depression using an in vitro mantle preparation. The metabolic\\u000a rate ofH. aspersa is depressed by 84% in vivo within 4 weeks of onset of estivation, and this metabolic depression is accompanied by a decrease\\u000a in haemolymphPO2 and pH, and

S. Pedler; C. J. Fuery; P. C. Withers; J. Flanigan; M. Guppy

1996-01-01

36

Toxicity of metals to a freshwater snail, Melanoides tuberculata.  

PubMed

Adult freshwater snails Melanoides tuberculata (Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT??) and concentrations (LC??) were calculated. LT?? and LC?? increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC(50) values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59?mg?L?¹, respectively. Cu was the most toxic metal to M. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration in M. tuberculata increases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC?? values for metals for this species with those for other freshwater gastropods reveals that M. tuberculata is equally sensitive to metals. PMID:22666089

Shuhaimi-Othman, M; Nur-Amalina, R; Nadzifah, Y

2012-04-24

37

Toxicity of Metals to a Freshwater Snail, Melanoides tuberculata  

PubMed Central

Adult freshwater snails Melanoides tuberculata (Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT50) and concentrations (LC50) were calculated. LT50 and LC50 increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC50 values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59?mg?L?1, respectively. Cu was the most toxic metal to M. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration in M. tuberculata increases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC50 values for metals for this species with those for other freshwater gastropods reveals that M. tuberculata is equally sensitive to metals.

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

2012-01-01

38

Population biology, genetic structure, and mating system parameters in freshwater snails  

Microsoft Academic Search

\\u000a Freshwater gastropods can reproduce by both uniparental and biparental means. In particular, self-fertilization in the hermaphrodite\\u000a pulmonates (Basommatophora) and apomictic parthenogenesis in prosobranchs are viable alternatives to biparental sexuality\\u000a in several species. The coexistence of different mating systems within and among extant populations provides opportunities\\u000a to examine the forces directing their evolution. We review the models predicting genetic structure in

T. Städler; P. Jarne

39

The influence of chemical cues and conspecific density on the temperature selection of a freshwater snail ( Melanoides tuberculata)  

Microsoft Academic Search

1. The effects of predation risk (via chemical cues) and conspecific density on temperature selection of the freshwater snail Melanoides tuberculata were assessed within a circular thermal gradient.2. Chemical cues from crushed conspecifics elicited the strongest avoidance response of snails in isothermal conditions.3. Following the addition of chemical cues to the thermal gradient, snails became more active and did not

Gary W. Gerald; Lawrence C. Spezzano

2005-01-01

40

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

41

Biological control of Biomphalaria glabrata, the intermediate host of schistosomes, by Marisa cornuarietis in ponds of Guadeloupe: long-term impact on the local snail fauna and aquatic flora  

Microsoft Academic Search

The efficiency of Marisa cornuarietis, a Venezuelan freshwater prosobranch was tested against Biomphalaria glabrata, a pulmonate snail which plays the role of intermediate host of human schistosomes in the Caribbean area. M. cornuarietis was introduced to 15 experimental ponds in Guadeloupe, while 15 control ponds were left unchanged. Populations of all species of freshwater molluscs as well as representative plant

J. P Pointier; P David

2004-01-01

42

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

43

Food selection by freshwater snails in the Gezira irrigation canals, Sudan  

Microsoft Academic Search

Stomach content analysis was carried out on samples of the freshwater snail species Biomphalaria pfeifferi, Bulinus truncatus, Bulinus forskalii (Pulmonata, Planorbidae), Lymnaea natalensis (Pulmonata, Lymnaeidae), Melanoides tuberculata, Cleopatra bulimoides (Prosobranchia, Thiaridae) and Lanistes carinatus (Prosobranchia, Ampullariidae) from different irrigation canals in Sudan. In order to evaluate overlap in diet selection\\u000a among these species, sites with two or more of the

Henry Madsen

1992-01-01

44

SPATIAL DISTRIBUTION OF THREE SNAIL SPECIES, INCLUDING THE INVADER POTAMOPYRGUS ANTIPODARUM, IN A FRESHWATER SPRING  

Microsoft Academic Search

The highly invasive New Zealand mudsnail, Potamopyrgus antipodarum, may compete with and displace native North American macroinvertebrates in freshwater systems wherever it becomes established. Densities and spatial distributions of 3 snail species including P. antipodarum and the threatened Taylorconcha serpenticola were compared among 3 adjacent habitat types (run, edge, and vegetation) in Banbury Springs, a tributary of the Snake River,

David C. Richards; L. Dianne Cazier; Gary T. Lester

45

Ecological components and evolution of selfing in the freshwater snail Galba truncatula  

Microsoft Academic Search

The reproductive assurance hypothesis emphasizes that self-fertilization should evolve in species with reduced dispersal capability, low population size or experiencing recurrent bottlenecks. Our work investigates the ecolog- ical components of the habitats colonized by the snail, Galba truncatula, that may influence the evolution of selfing. Galba truncatula is a preferential selfer inhabiting freshwater habitats, which vary with respect to the

S. T ROUVE; L. D EGEN; J. G OUDET

2005-01-01

46

The Genetical and Environmental Determination of Phally Polymorphism in the Freshwater Snail Bulinus Truncatus  

PubMed Central

In some species of self-fertile pulmonate snails, two sexual morphs co-occur in natural populations: regular individuals and aphallic individuals that cannot transmit sperm to other snails. Purely aphallic populations therefore reproduce obligatorily by selfing. Understanding the evolution of aphally and selfing in these snails requires a precise knowledge of phally determination. In this paper, we investigate the genetic and environmental determination of aphally in Bulinus truncatus by a survey of the family (offspring) aphally ratio of 233 individuals originating from seven natural populations and a study of the reaction norm of the family aphally ratio to temperature using 60 individuals from 10 selfed lineages of one population. Our results indicate a high genetic variability for the determination of aphally between populations and within some populations, associated with a high level of genetic determination. Our second experiment indicates a significant temperature and lineage effect though no interaction between these two effects. We discuss our results in the framework of threshold models developed for dimorphic traits with polygenic inheritance. We propose that the sexual morph of an individual at a given temperature is determined by a temperature threshold value depending on both the individual genotype and probabilistic processes.

Doums, C.; Bremond, P.; Delay, B.; Jarne, P.

1996-01-01

47

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

PubMed Central

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

Gloer, Peter; Pesic, Vladimir

2012-01-01

48

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

2007-04-25

49

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

Microsoft Academic Search

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

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

2000-01-01

50

Ecology of Freshwater Snails in Opa Reservoir and Research Farm Ponds at Obafemi Awolowo University Ile-Ife, Nigeria  

Microsoft Academic Search

In a 12 month study, the ecology of freshwater snails in Opa Reservoir (OR) and Research Farm Ponds (RFPs), in Obafemi Awolowo University, Ile-Ife, Nigeria, was studied. During each monthly visit, eleven sites (seven sites in OR and four sites in RFPs) were sampled for relative snail density, vegetation cover and physicochemical properties of the water bodies. The data were

O. J. Owojori; S. O. Asaolu; I. E. Ofoezie

2006-01-01

51

Influence of salt concentrations on survival, body weight and blood chloride of the freshwater snail, Indoplanorbis exustus (Deshyes)  

Microsoft Academic Search

A study was made on I. exustus to observe the survival and osmotic regulation following transfer of snails from freshwater to different salt concentrations. The lethal salinity was found at 0.5% salt concentration. It was observed that there was loss of chloride ions in distilled water whereas the snails gained chloride in different salt concentrations. The gain of chloride ions

D. P. Vaidya; R. Nagabhushanam

1979-01-01

52

Predatory Potential of Freshwater Animals on an Invasive Agricultural Pest, the Apple Snail Pomacea canaliculata (Gastropoda: Ampullariidae), in Southern Japan  

Microsoft Academic Search

The apple snail Pomacea canaliculata is an invasive species and a serious pest of rice in many Asian countries. We studied predatory activities of various animals living in Japanese freshwater habitats, by keeping each individual of a potential predator species with 36 snails of various sizes for three days in the aquarium. Forty-six species were tested, and 26 in eight

Yoichi Yusa; Naoyuki Sugiura; Takashi Wada

2006-01-01

53

Molecular phylogenetic relationships in the aquatic snail genus Lymnaea , the intermediate host of the causative agent of fascioliasis: insights from broader taxon sampling  

Microsoft Academic Search

Phylogenetic analyses were performed on partial mitochondrial (16S) gene sequences that included new 16S data for 23 exemplars of the freshwater pulmonate snail genus Lymnaea sensu lato and putative outgroup species. This procedure yielded relatively congruent patterns of evolutionary divergence and phylogenetic affinities, and greater resolution and support for many lineages at different levels of divergence than from a previous

E. A. Remigio

2002-01-01

54

Evolution and ecological correlates of uniparental and biparental reproduction in freshwater snails  

Microsoft Academic Search

\\u000a We review the spatial and temporal correlates of uniparental and biparental reproduction in three species of freshwater snails\\u000a as they pertain to the ecological hypotheses for the maintenance of biparental sex. The biogeographic evidence from two species\\u000a (Potamopyrgus antipodarum and Bulinus truncatus) presently supports the Red Queen hypothesis that biparental reproduction is selected as a way to reduce the risk

S. G. Johnsonl; C. M. Lively; S. J. Schrag

55

Lead toxicity, locomotion and feeding in the freshwater snail, Lymnaea stagnalis (L.)  

Microsoft Academic Search

.   The effects of lead (5 or 10 ppm) on the survival of the freshwater snail Lymnaea stagnalis (L.) collected from lead contaminated or uncontaminated environments were evaluated under controlled laboratory conditions.\\u000a The animals from the contaminated environment had significantly greater survivability than those from the unpolluted environment\\u000a to subsequent acute (up to 24 days) exposure to lead. Acute (72 h) exposure to

A. Pyatt; F. Pyatt; V. W. Pentreath

2002-01-01

56

Oxidative stress and genotoxic effect of zinc oxide nanoparticles in freshwater snail Lymnaea luteola L.  

PubMed

Understanding the toxic effects of nanoparticles on aquatic organism is the biggest obstacle to the safe development of nanotechnology. However, little is known about the toxic mechanisms of zinc oxide nanoparticles (ZnONPs) in freshwater snail Lymnaea luteola (L. luteola). This study was designed to investigate the possible mechanisms of genotoxicity induced by ZnONPs in freshwater snail L. luteola. ZnONPs (32 ?g/ml) elicited a significant (p<0.01) reduction in glutathione (42.10% and 61.40%), glutathione-S-transferase (25.60% and 40.24%) and glutathione peroxidase (21.73% and 39.13%) with a concomitant increase in malondialdehyde level (54.50% and 57.14%; p<0.01) and catalase (34.88% and 52.56%; p<0.01) in digestive gland of L. luteola after 24 and 96 h exposure, respectively. However, a statistically significant (p<0.01) induction in DNA damage was observed by the comet assay in digestive gland cells treated with ZnONPs for 24 and 96 h. Thus, the results demonstrate that ZnONPs induce genotoxicity in digestive gland cells through oxidative stress. Freshwater snail L. luteola may be used as suitable test model for nanoecotoxicological studies in future. PMID:22917558

Ali, Daoud; Alarifi, Saud; Kumar, Sudhir; Ahamed, Maqusood; Siddiqui, Maqsood A

2012-08-08

57

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

58

Predator-induced morphological plasticity across local populations of a freshwater snail.  

PubMed

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

Brönmark, Christer; Lakowitz, Thomas; Hollander, Johan

2011-07-19

59

Accelerated Mutation Accumulation in Asexual Lineages of a Freshwater Snail  

PubMed Central

Sexual reproduction is both extremely costly and widespread relative to asexual reproduction, meaning that it must also confer profound advantages in order to persist. One theorized benefit of sex is that it facilitates the clearance of harmful mutations, which would accumulate more rapidly in the absence of recombination. The extent to which ineffective purifying selection and mutation accumulation are direct consequences of asexuality and whether the accelerated buildup of harmful mutations in asexuals can occur rapidly enough to maintain sex within natural populations, however, remain as open questions. We addressed key components of these questions by estimating the rate of mutation accumulation in the mitochondrial genomes of multiple sexual and asexual representatives of Potamopyrgus antipodarum, a New Zealand snail characterized by mixed sexual/asexual populations. We found that increased mutation accumulation is associated with asexuality and occurs rapidly enough to be detected in recently derived asexual lineages of P. antipodarum. Our results demonstrate that increased mutation accumulation in asexuals can differentially affect coexisting and ecologically similar sexual and asexual lineages. The accelerated rate of mutation accumulation observed in asexual P. antipodarum provides some of the most direct evidence to date for a link between asexuality and mutation accumulation and implies that mutational buildup could be rapid enough to contribute to the short-term evolutionary mechanisms that favor sexual reproduction.

Neiman, Maurine; Hehman, Gery; Miller, Joseph T.; Logsdon, John M.; Taylor, Douglas R.

2010-01-01

60

Accelerated mutation accumulation in asexual lineages of a freshwater snail.  

PubMed

Sexual reproduction is both extremely costly and widespread relative to asexual reproduction, meaning that it must also confer profound advantages in order to persist. One theorized benefit of sex is that it facilitates the clearance of harmful mutations, which would accumulate more rapidly in the absence of recombination. The extent to which ineffective purifying selection and mutation accumulation are direct consequences of asexuality and whether the accelerated buildup of harmful mutations in asexuals can occur rapidly enough to maintain sex within natural populations, however, remain as open questions. We addressed key components of these questions by estimating the rate of mutation accumulation in the mitochondrial genomes of multiple sexual and asexual representatives of Potamopyrgus antipodarum, a New Zealand snail characterized by mixed sexual/asexual populations. We found that increased mutation accumulation is associated with asexuality and occurs rapidly enough to be detected in recently derived asexual lineages of P. antipodarum. Our results demonstrate that increased mutation accumulation in asexuals can differentially affect coexisting and ecologically similar sexual and asexual lineages. The accelerated rate of mutation accumulation observed in asexual P. antipodarum provides some of the most direct evidence to date for a link between asexuality and mutation accumulation and implies that mutational buildup could be rapid enough to contribute to the short-term evolutionary mechanisms that favor sexual reproduction. PMID:19995828

Neiman, Maurine; Hehman, Gery; Miller, Joseph T; Logsdon, John M; Taylor, Douglas R

2009-12-08

61

Changes in chemical components in the freshwater apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae), in relation to the development of its cold hardiness  

Microsoft Academic Search

The apple snail, Pomacea canaliculata, is an invasive freshwater snail. It increases its cold hardiness before winter. However, the physiological mechanism of cold hardiness in molluscs is poorly understood, especially in freshwater molluscs. In this study, we examined the changes in low molecular weight compounds, glycogen and lipids, in the body of P. canaliculata in association with the development of

Keiichiro Matsukura; Hisaaki Tsumuki; Yohei Izumi; Takashi Wada

2008-01-01

62

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

Microsoft Academic Search

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

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

2010-01-01

63

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

PubMed Central

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

2011-01-01

64

Invading freshwater snails and biological control in Martinique Island, French West Indies.  

PubMed

Eight alien freshwater snail species were introduced into Martinique Island during the last 50 years. The introduced snails include four planorbids (Biomphalaria straminea, Helisoma duryi, Amerianna carinata and Gyraulus sp.), three thiarids (Melanoides tuberculata, M. amabilis and Tarebia granifera) and one ampullarid (Marisa cornuarietis). Four of these species rapidly colonized the whole Martinican hydrographic system whereas the other four remained restricted to some particular sites. The invasion processes were documented during the last 20 years and showed (i) a rapid invasion of the island by several morphs of M. tuberculata at the beginning of the 80's; (ii) the introduction of T. granifera in 1991 and M. amabilis in 1997; and (iii) the rapid spread of these last two species throughout the island. In the years following its introduction, M. tuberculata was used in biological control experiments against the snail hosts of schistosomiasis, B. glabrata and B. straminea. Experiments were conducted with success in several groups of water-cress beds which constituted the latest transmission sites for schistosomiasis at the beginning of the 80's. A malacological survey carried out in 2000 all over the island showed the absence of B. glabrata but the presence of some residual populations of B. straminea. Long-term studies carried out in Martinique have shown that the thiarids are able to maintain relatively stable populations over a long period of time, thus preventing recolonization by the snail hosts. Within this context the invasion of the hydrographic system of Martinique by thiarid snails has resulted in an efficient and sustainable control of the intermediate hosts of schistosomiasis. PMID:11586428

Pointier, J P

2001-01-01

65

Histopathological effects of Thiodan on the freshwater snail, Galba truncatula (gastropoda, pulmonata).  

PubMed

Histopathological alterations in three tissues, namely, digestive gland, foot and mantle of the freshwater snail Galba truncatula induced by Thiodan 35 EC, a commercial preparation of endosulfan, were studied in the laboratory. The snails were exposed to five sublethal concentrations of Thiodan, two of them higher concentrations at 0.33% and 0.65% in glass jars for short-term exposure (96 h) and three of them lower concentrations at 0.08%, 0.16% and 0.27% for long-term exposure (10, 20 and 30 days). Thiodan caused significant histopathological changes in the tissues of the snail, irrespective of the concentration of the pesticide and its exposure period. The histopathological changes included accumulation of amoebocytes in the hemolymphatic spaces between the tubules of the digestive gland, exudation in the lumen of tubules, expansion of hemolymphatic spaces between the tubules and increase of vacuolation and necrotic changes in the digestive cells. Disruption of columnar muscle fibers and alteration of epithelial layers were detected in the foot and mantle of the treated specimens. The number and size of mucous and protein cells in the foot and mantle also changed. PMID:16092081

Cengiz, Elif I; Yildirim, Mehmet Z; Otludil, Birgül; Unlü, Erhan

66

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

PubMed

An infection with Angiostrongylus cantonensis, the main causative agent for human eosinophilic encephalitis, can be acquired through the consumption of the freshwater snail Pomacea canaliculata. This snail also provides a suitable model to study the developmental morphology and behavior of A. cantonensis larvae, facilitated by the snail's distinct lung structure. We used microanatomy for studying the natural appearance and behavior of A. cantonensis larvae while developing within P. canaliculata. The distribution of refractile granules in the larval body and characteristic head structures changed during the developmental cycle. Two well-developed, rod-like structures with expanded knob-like tips at the anterior part were observed under the buccal cavity as early as the late second developmental stage. A "T"-shaped structure at the anterior end and its tenacity distinguished the outer sheath from that shed during the second molting. Early first-stage larvae obtained from fresh rat feces are free moving and characterized by a coiled tail, whereas a mellifluous "Q"-movement was the behavioral trait of third-stage A. cantonensis larvae outside the host tissue. In combination, the distribution of refractive granules, distinct head features, variations in sheaths, and behavioral characteristics can be utilized for differentiation of larval stages, and for distinguishing A. cantonensis larvae from those of other free-living nematodes. PMID:19172296

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

2009-01-27

67

Microsatellites and the genetics of highly selfing populations in the freshwater snail Bulinus truncatus.  

PubMed

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 < or = 41 alleles for one locus and gene diversity of 0.20-0.75 among populations. The values of any estimator of Fis 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 Fst, Rst 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

1996-04-01

68

Understanding the Regulation of Estivation in a Freshwater Snail through iTRAQ-Based Comparative Proteomics.  

PubMed

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

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

2013-10-02

69

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

PubMed

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

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

2007-11-01

70

Hybridization and invasiveness in the freshwater snail Melanoides tuberculata: hybrid vigour is more important than increase in genetic variance  

Microsoft Academic Search

Many invasive taxa are hybrids, but how hybridization boosts the invasive process remains poorly known. We address this question in the clonal freshwater snail Melanoides tuberculata from Martinique, using three parental and two hybrid lines. We combine an extensive field survey (1990-2003) and a quantitative genetic experiment to show that hybrid lines have outcompeted their parents in natural habitats, and

B. FACON; P. JARNE; J. P. POINTIER; P. DAVID

2005-01-01

71

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

72

High quantitative and no molecular differentiation of a freshwater snail (Galba truncatula) between temporary and permanent water habitats  

Microsoft Academic Search

We investigate the variation in quantitative and molecular traits in the freshwater snail Galba truncatula, from permanent and temporary water habitats. Using a common garden experiment, we measured 20 quantitative traits and molecular variation using seven microsatellites in 17 populations belonging to these two habitats. We estimated trait means in each habitat. We also estimated the distributions of overall genetic

ELODIE CHAPUIS; SANDRINE TROUVE; BENOIT FACON; LOÏC DEGEN; JEROME GOUDET

2007-01-01

73

Heterosis and inbreeding depression in bottlenecked populations: a test in the hermaphroditic freshwater snail Lymnaea stagnalis.  

PubMed

Small population size is expected to induce heterosis, due to the random fixation and accumulation of mildly deleterious mutations, whereas within-population inbreeding depression should decrease due to increased homozygosity. Population bottlenecks, although less effective, may have similar consequences. We tested this hypothesis in the self-fertile freshwater snail Lymnaea stagnalis, by subjecting experimental populations to a single bottleneck of varied magnitude. Although patterns were not strong, heterosis was significant in the most severely bottlenecked populations, under stressful conditions. This was mainly due to hatching rate, suggesting that early acting and highly deleterious alleles were involved. Although L. stagnalis is a preferential outcrosser, inbreeding depression was very low and showed no clear relationship with bottleneck size. In the less reduced populations, inbreeding depression for hatching success increased under high inbreeding. This may be consistent with the occurence of synergistic epistasis between fitness loci, which may contribute to favour outcrossing in L. stagnalis. PMID:21767319

Coutellec, M-A; Caquet, T

2011-07-18

74

Ecological components and evolution of selfing in the freshwater snail Galba truncatula.  

PubMed

The reproductive assurance hypothesis emphasizes that self-fertilization should evolve in species with reduced dispersal capability, low population size or experiencing recurrent bottlenecks. Our work investigates the ecological components of the habitats colonized by the snail, Galba truncatula, that may influence the evolution of selfing. Galba truncatula is a preferential selfer inhabiting freshwater habitats, which vary with respect to the degree of permanence. We considered with a population genetic approach the spatial and the temporal degree of isolation of populations of G. truncatula. We showed that patches at distances of only a few meters are highly structured. The effective population sizes appear quite low, in the order of 10 individuals or less. This study indicates that individuals of the species G. truncatula are likely to be alone in a site and have a low probability of finding a partner from a nearby site to reproduce. These results emphasize the advantage of selfing in this species. PMID:15715842

Trouve, S; Degen, L; Goudet, J

2005-03-01

75

Field observations of the alarm response to crushed conspecifics in the freshwater snail Pomacea canaliculata : effects of habitat, vegetation, and body size  

Microsoft Academic Search

The freshwater snail Pomacea canaliculata shows alarm responses to chemical cues released from injured conspecifics, but its behavioural responses in the field are\\u000a unknown. We investigated effects of habitat (canals or paddy fields), vegetation, and body size on alarm responses in the\\u000a field. Snails responded to crushed conspecifics within 4 min by burying themselves, but the proportions of self-buried snails\\u000a were

Kahori Aizaki; Yoichi Yusa

2009-01-01

76

Sediment copper bioavailability to freshwater snails in south Florida: risk implications for the Everglade snail kite ( Rostrhamus sociabilis plumbeus )  

Microsoft Academic Search

Many properties being acquired as part of the Comprehensive Everglades Restoration Plan (CERP) are heavily contaminated with\\u000a copper. Estimated copper bioaccumulation in the Florida apple snail (Pomacea paludosa) has led to the prediction of risk to the Everglade snail kite (Rostrhamus sociabilis plumbeus) at some CERP projects. Field study results presented in this paper examine the relationship between copper levels

Robert A. Frakes; Timothy A. Bargar; Emily A. Bauer

2008-01-01

77

Palaeoclimatic implications of isotopic data from modern and early Holocene shells of the freshwater snail Melanoides tuberculata, from lakes in the Ethiopian Rift Valley  

Microsoft Academic Search

Carbon and oxygen isotope ratios in the shells of the freshwater snail Melanoides tuberculata yield information on the isotopic composition of the water in which the shell was formed, which in turn relates to climatic conditions prevailing during the snails' life span. Melanoides is particularly important because it is widespread in Quaternary deposits throughout Africa and Asia and is ubiquitous

Melanie J. Leng; Angela L. Lamb; Henry F. Lamb; Richard J. Telford

1999-01-01

78

The Oxygen, Hydrogen and Carbon Isotope Compositions of Modern Freshwater and Terrestrial Snails, Pinery Provincial Park, Southern Great Lakes Area, Canada  

Microsoft Academic Search

We have compared the oxygen, hydrogen and carbon isotope compositions of several species of modern freshwater and terrestrial snails from a variety of ecosystems in Pinery Provincial Park, southwestern Ontario. The Park is located on the shore of Lake Huron, within a temperate-humid climatic regime. The aquatic snails have a range of oxygen and hydrogen isotope body-water compositions with a

J. Heidenheim; F. Longstaffe

2005-01-01

79

Electron Spin Resonance Studies of Mn2+ in Freshwater Snail Shells:  

NASA Astrophysics Data System (ADS)

We have studied paramagnetic Mn2+ ions present in the shells of today's univalve freshwater snails, Sinotaia ingallsiana (FS), Pila ampullaceal (PA), Pomacea canaliculata lamarck (PCL) and the fossilized freshwater snail (FFS), Viviparus which are abundant in Thailand. The FS, PA and AG shells in our study were ground into fine powder. A set of seven samples was each then separately annealed for 2 hours in air atmosphere at 300°C, 400°C, 450°C, 500°C, 550°C, 600°C and 900°C, respectively, while the FFS powder was characterized as received. The FS, PA and PCL shells mainly consist of aragonite and a fraction of calcite. The heat treatments higher than 450°C of the FS, PA and PCL powder samples resulted in an irreversible phase transformation from aragonite to calcite. However, it is found that the FFS shell is mainly made of calcite, with a minor fraction of aragonite. The crystal structure of high temperature annealed FS, PA and PCL samples are quite similar to that of FFS, which indicates that the metamorphosis (aragonite ? calcite) in the FFS shell had occurred but not yet completed, although they remained under the pressure and temperature of the Earth's crust over millions of years. Our detailed ESR spectral analyses of FS, PA, PCL and FFS show that Mn2+ ions enter Ca2+ sites during a biomineralization process. Typical simulated ESR parameters of FS-500 of Mn2+ at a uniaxial site of calcite are gx=gy=2.078±0.001, gz=2.002±0.001, Ax=Ay=87.50±1.00 G, Az=89.00±1.00 G and D=115±1 G, respectively. It is surprising to find that the ratio of Mn2+ concentration present in FFS to those in FS, PA and PCL shells evaluated from ESR spectra is as much as 10:1. It is thus possible to gain some insight of manganese incorporation into the freshwater shells during the biomineralization process.

Meejoo, S.; Udomkan, N.; Winotai, P.; Chaimanee, Y.

80

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

81

Sediment copper bioavailability to freshwater snails in south Florida: risk implications for the Everglade snail kite (Rostrhamus sociabilis plumbeus).  

PubMed

Many properties being acquired as part of the Comprehensive Everglades Restoration Plan (CERP) are heavily contaminated with copper. Estimated copper bioaccumulation in the Florida apple snail (Pomacea paludosa) has led to the prediction of risk to the Everglade snail kite (Rostrhamus sociabilis plumbeus) at some CERP projects. Field study results presented in this paper examine the relationship between copper levels in sediments, snails, and other biota. Copper concentrations in all biota (snails, aquatic vascular plants, and periphyton) were strongly correlated with those in sediments. No correlation with water copper concentrations was evident. Mean copper concentrations in snails ranged from 23.9 mg/kg at the reference site to 732 mg/kg at a high copper site. Calculated biota-sediment accumulation factors (BSAFs) ranged from 36.7 to 7.0 over the range of copper levels in sediments. BSAFs were highest at low copper levels in sediments and declined sharply as copper levels in sediment increased. Risk for the snail kite is discussed in light of the results of this study. PMID:18679796

Frakes, Robert A; Bargar, Timothy A; Bauer, Emily A

2008-08-05

82

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

PubMed Central

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

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

2008-01-01

83

The use of a lysosome assay for the rapid assessment of cellular stress from copper to the freshwater snail Viviparus contectus (Millet)  

Microsoft Academic Search

To enable efficient monitoring and the early detection of toxic metal effects a rapid low cost test has been developed for use with freshwater gastropods. A cellular assay formerly developed for marine organisms has been modified for use with freshwater snails. A modified neutral-red retention assay makes use of the fact that lysosomes in unstressed cells retain the neutral-red dye

Claus Svendsen

1995-01-01

84

No evidence for a critical salinity threshold for growth and reproduction in the freshwater snail Physa acuta.  

PubMed

The growth and reproduction of the freshwater snail Physa acuta (Gastropoda: Physidae) were measured at various salinity levels (growth: distilled water, 50, 100, 500, 1000 and 5000 microS/cm; reproduction: deionized water, 100, 500, 1000 and 3000 microS/cm) established using the artificial sea salt, Ocean Nature. This was done to examine the assumption that there is no direct effect of salinity on freshwater animals until a threshold, beyond which sub-lethal effects, such as reduction in growth and reproduction, will occur. Growth of P. acuta was maximal in terms of live and dry mass at salinity levels 500-1000 microS/cm. The number of eggs produced per snail per day was maximal between 100 and 1000 microS/cm. Results show that rather than a threshold response to salinity, small rises in salinity (from low levels) can produce increased growth and reproduction until a maximum is reached. Beyond this salinity, further increases result in a decrease in growth and reproduction. Studies on the growth of freshwater invertebrates and fish have generally shown a similar lack of a threshold response. The implications for assessing the effects of salinisation on freshwater organisms need to be further considered. PMID:15620583

Kefford, Ben J; Nugegoda, Dayanthi

2005-04-01

85

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.

Koene, Joris M.

2010-01-01

86

Selfing, sexual polymorphism and microsatellites in the hermaphrodititic freshwater snail Bulinus truncatus  

PubMed Central

Studies on the evolution of self-fertilization and sexual polymorphisms (the co-occurrence of several sexual morphs in a species) have focused on plants. Aphally, a sexual polymorphism occurring in gastropods, offers the opportunity to extend study of these issues to animals. We present progeny-array analyses of the selfing rate and correlated matings in the tropical freshwater snail Bulinus truncatus. This study is based on 447 offspring originating from 57 families and five natural populations. To overcome the lack of allozyme polymorphism, four polymorphic microsatellite markers were used. Selfing rates higher than 78 per cent were detected in all populations, and no correlation with the aphally ratio (the proportion of individuals lacking the male copulatory organ per population) was evident. Outcrossing was detected in 17 families only, and individual outcrossing rates were variable and did not depend on the sexual morph of the mother. These results illustrate the power of microsatellites for detailed genetic studies, indicate that high selfing rates may have a strong genetic basis, and unexpectedly suggest that phally polymorphism may be neutral with respect to selfing.

Viard, F.; Doums, C.; Jarne, P.

1997-01-01

87

Prosobranch snails as test organisms for the assessment of endocrine active chemicals––an overview and a guideline proposal for a reproduction test with the freshwater mudsnail Potamopyrgus antipodarum  

Microsoft Academic Search

Recently, prosobranch snails have been recommended as promising candidates for test organisms for the assessment of endocrine\\u000a active chemicals. Three prosobranch snail species, the freshwater mudsnail Potamopyrgus antipodarum, the freshwater ramshorn snail Marisa cornuarietis, and the marine netted whelk Nassarius reticulatus are portrayed and their respective biotests are presented together with results of laboratory experiments and biological\\u000a effect monitoring surveys

Martina Duft; Claudia Schmitt; Jean Bachmann; Cornelius Brandelik; Ulrike Schulte-Oehlmann; Jörg Oehlmann

2007-01-01

88

No effect of mate novelty on sexual motivation in the freshwater snail Biomphalaria glabrata  

PubMed Central

Background When mating effort (e.g. via ejaculates) is high, males are expected to strategically allocate their resources depending on the expected fitness gains from a given mating opportunity. One mechanism to achieve strategic mating is the Coolidge effect, where male sexual motivation declines across repeated encounters with a familiar partner, but resuscitates when encountering a novel female. Experimental tests of male mate choice via mechanisms such as the Coolidge effect, however, remain scarce. Moreover, it is untested to date whether the Coolidge effect occurs in a sex-specific manner in simultaneous hermaphrodites, where the motivation to mate with a familiar partner may vary with previous mating activity in the male or female role. Results We exposed focal hermaphroditic freshwater snails, Biomphalaria glabrata, repeatedly to either a familiar or a novel partner. None of our proxies of sexual motivation (remating likelihood, mating delay, copulation duration) varied between the novel and familiar partner treatments. Moreover, the mating role taken during the first copulation did not affect the subsequent choice of mating roles in the familiar partner treatment as would be expected if focals preferred to avoid mating twice in the same role with a familiar partner. This indicates the absence of sex-specific effects of partner novelty. Conclusion Our data indicate that mate novelty does affect neither overall sexual motivation nor the choice of mating roles in B. glabrata. Hence, male mate choice via a Coolidge effect appears inexistent in this invertebrate hermaphrodite. We discuss the possible roles of insufficient fitness gains for discriminatory behaviour in populations with frequent mate encounters as well as poor mate discrimination capacities. Our findings lend also no support to the novel prediction that sexual motivation in simultaneous hermaphrodites varies with the mating roles taken during previous copulations, calling for empirical investigation in further hermaphrodite systems.

Haderer, Ines K; Werminghausen, Johanna; Michiels, Nico K; Timmermeyer, Nadine; Anthes, Nils

2009-01-01

89

Microsatellite size homoplasy, SSCP, and population structure: a case study in the freshwater snail Bulinus truncatus.  

PubMed

The extent of microsatellite size homoplasy, as well as its effect on several population genetics statistics, was investigated in natural populations using the single-strand conformation polymorphism (SSCP) method. The analysis was conducted using 240 individuals from 13 populations of the freshwater snail Bulinus truncatus at a GT(n)CT(m) compound microsatellite locus. We showed that SSCP can be used to uncover, at least partly, size homoplasy in the core sequence of this category of loci. Eight conformers (SSCP variants) were detected among the three size variants (electromorphs). Sequencing revealed that each conformer corresponded to a different combination of repeats in the GT(n) and CT(m) arrays. Part of this additional variability was detected within populations, resulting in a substantial increase in gene diversity in four populations. Additional variability also changed the values of parameters used to analyze population differentiation among populations: pairwise tests of differentiation were significant much more often with conformers than with electromorphs. On the other hand, pairwise estimates of F(st) were either smaller or larger with conformers than with electromorphs, depending on whether or not electromorphs were shared among populations. However, estimates of F(st) (or analogs) over all populations were very similar, ranging between 0.66 and 0.75. Our results were consistent with the theoretical prediction that homoplasy should not always lead to stronger population structure. Finally, conformer sequences and electromorph size distribution suggested that single-point and/or stepwise mutations occurring simultaneously in the different repeated arrays of compound microsatellites produce sequence variation without size variation and hence generate more size homoplasy than expected under a simple stepwise mutation model. PMID:11110909

Angers, B; Estoup, A; Jarne, P

2000-12-01

90

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.

Bdir, Sami; Adwan, Ghaleb

2011-01-01

91

Distribution of freshwater snails in the man-made Oyan Reservoir, Ogun State, Nigeria  

Microsoft Academic Search

The factors influencing patterns of snail distribution in Oyan Reservoir, a typically medium sized man-made reservoir in southwest Nigeria, were investigated once a month, for 28 months (August 1990-November 1992). During each monthly visit, seven stations were sampled for relative snail density, vegetation cover and physical and chemical properties of the lake water. Statistical analyses were performed to determine the

Ifeanyi Emmanuel Ofoezie

1999-01-01

92

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

PubMed Central

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

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

2012-01-01

93

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

94

Preliminary observation of the susceptibility of some freshwater snails to the infection with Varestrongylus sagittatus (Nematoda: Protostrongylidae).  

PubMed

Under laboratory conditions, the freshwater snails Galba truncatula Müll.), Radix peregra (Müll.) and Planorbarius corneus (L.) have been successfully infected with the first stage larvae of the protostrongylid nematode Varestrongylus sagittatus (Mueller, 1890) Dougherty, 1945. The net rate of the infection (mean number of larvae per snail examined - l/s) was 6.2 l/s in R. peregra and 3.5 l/s in P. corneus. G. truncatula was susceptible to the infection too (36.3 l/s). However, this result can be considered as pilot only, because of the low number of the specimens of this species examined. At 25 degrees C 50% of V. sagittatus larvae reached the 3-rd stage of development by 12.5 days post infection (DPI) in R. peregra and by 17.8 DPI in P. corneus. It was confirmed that the snail species of the Basommatophora that were studied can act as intermediate hosts of the nematode V. sagittatus under laboratory conditions. PMID:1822468

Rezác, P

1991-01-01

95

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

PubMed

Population response to anthropogenic activities will be influenced by prior adaptation to environmental conditions. We tested how parasite-resistant and -susceptible strains of the freshwater snail, Biomphalaria glabrata, 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) lethal 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 lethal cadmium challenges, while BS90 became more tolerant of lethal cadmium challenge only. Fitness costs, reflected in population growth rate, were not apparent in fifth generation snails maintained in control 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. PMID:20703799

Salice, Christopher J; Anderson, Todd A; Roesijadi, G

2010-08-12

96

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

2011-10-14

97

Effects of acidic water on freshwater snails: results from a study of 1000 lakes throughout Norway.  

PubMed

This paper summarizes some results from a monograph which focused on ecological and biogeographical aspects of the biota in Norwegian lakes and rivers with particular reference to the snail fauna. Field studies were made in the course of 20 summers within the period of 1953-1987. Acidic water is the main reason why snails are absent from some 4000 lakes in a low-calcium area in southern Norway ('Acid south'). This area is heavily influenced by acidic precipitation. Snails were not detected in lakes with pH below 5.2. In one lake, three snail species disappeared in parallel with acidification from pH 5.2 to 4.2. The calcium level modified the effect of low pH. PMID:15091938

Økland, J

1992-01-01

98

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

2012-09-06

99

The Value of the Freshwater Snail Dip Scoop Sampling Method in Macroinvertebrates Bioassessment of Sugar Mill Wastewater Pollution in Mbandjock, Cameroon  

PubMed Central

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

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

2008-01-01

100

Hybridization and invasiveness in the freshwater snail Melanoides tuberculata: hybrid vigour is more important than increase in genetic variance.  

PubMed

Many invasive taxa are hybrids, but how hybridization boosts the invasive process remains poorly known. We address this question in the clonal freshwater snail Melanoides tuberculata from Martinique, using three parental and two hybrid lines. We combine an extensive field survey (1990-2003) and a quantitative genetic experiment to show that hybrid lines have outcompeted their parents in natural habitats, and that this increased invasiveness co-occurred with pronounced shifts in life-history traits, such as growth, fecundity and juvenile size. Given the little time between hybrid creation and sampling, and the moderate standing genetic variance for life-history traits in hybrids, we show that some of the observed trait changes between parents and hybrids were unlikely to arise only by continuous selection. We therefore suggest that a large part of hybrid advantage stems from immediate heterosis upon hybridization. PMID:15842482

Facon, B; Jarne, P; Pointier, J P; David, P

2005-05-01

101

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

PubMed

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

102

High quantitative and no molecular differentiation of a freshwater snail (Galba truncatula) between temporary and permanent water habitats.  

PubMed

We investigate the variation in quantitative and molecular traits in the freshwater snail Galba truncatula, from permanent and temporary water habitats. Using a common garden experiment, we measured 20 quantitative traits and molecular variation using seven microsatellites in 17 populations belonging to these two habitats. We estimated trait means in each habitat. We also estimated the distributions of overall genetic quantitative variation (QST), and of molecular variation (FST), within and between habitats. Overall, we observed a lack of association between molecular and quantitative variance. Among habitats, we found QST>FST, an indication of selection for different optima. Individuals from temporary water habitat matured older, at a larger size and were less fecund than individuals from permanent water habitat. We discuss these findings in the light of several theories for life-history traits evolution. PMID:17688547

Chapuis, Elodie; Trouve, Sandrine; Facon, Benoit; Degen, Loïc; Goudet, Jerome

2007-08-01

103

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

PubMed

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-N T; Jarne, P; Konan, J-N K; Utzinger, J; N'Goran, E K

2013-01-16

104

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

PubMed

In a survey carried out during Summer and Autumn of 2004, for snails of medical importance, nine species were recovered. These were Biomphalaria alexandrina, B. glabrata, B. pfeifferi, Bulinus truncatus, B. forskalii, Lymnaea natalensis, Bellamya (=Vivipara) unicolor, Physa acuta and Hydrobia musaensis. Parasitological examination revealed that B. alexandrina, B. glabrata and L. natalensis harboured immature stages of their concerned trematode parasites. Moreover, P. acuta harboured the immature stage of the nematode parasite Parastrongylus cantonensis. PMID:15880994

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

2005-04-01

105

A high incidence of clustered microsatellite mutations revealed by parent-offspring analysis in the African freshwater snail, Bulinus forskalii (Gastropoda, Pulmonata)  

Microsoft Academic Search

Genotyping of 11 microsatellites in 432 offspring from 28 families of the hermaphroditic, freshwater snail Bulinus forskalii detected 10 de novo mutant alleles. This gave an estimated mutation rate of 1.1 × 10-3 per locus per gamete per generation. There was a trend towards repeat length expansion and, unlike most studies, multi-step mutations predominated, suggesting that the microsatellite mutation process

Jennifer L. Gow; Leslie R. Noble; David Rollinson; Catherine S. Jones

2005-01-01

106

Adaptive Radiation in the Larval Feeding Habits of the Snail-Killing Fly Genus Tetanocera (Diptera: Sciomyzidae)  

Microsoft Academic Search

The genus Tetanocera consists of 29 species in North America. The genus is unusual in that its larvae occupy five of the 17 feeding groups recognized in the family, as most other genera of the family occupy only one or two trophic guilds. Seven species have larvae that attack pulmonate aquatic snails, three species attack pulmonate snails stranded on shorelines,

B. A. Foote

2005-01-01

107

Clonal structure of the introduced freshwater snail Potamopyrgus antipodarum (Prosobranchia: Hydrobiidae), as revealed by DNA fingerprinting.  

PubMed

Multi-locus DNA fingerprints were obtained from individuals of the hydrobiid snail, Potamopyrgus antipodarum (= P. jenkinsi), by using an RNA derivative (pSPT 18.15) of Jeffrey's 33.15 minisatellite core sequence. Whole-body homogenization of snails yielded 3.21 +/- 0.09 micrograms DNA per individual, producing complex profiles comprising 12-22 fragments within the 1.0-20.0 kilobase (kb) size range. Fingerprints from natural and experimental populations identified three distinct clonal genotypes corresponding to morphological strains A, B and C, with only rare mutational variants. Mother-offspring comparisons of genetic fingerprints revealed genetic stability during apomictic parthenogenesis. Data support the notion that British populations of P. antipodarum comprise three widespread obligate parthenogenetic clones resulting from a mid-19th Century introduction from Australasia. The present-day low levels of genotypic diversity are discussed in relation to the typical occurrence of P. antipodarum in man-made or immature habitats. PMID:1359547

Hauser, L; Carvalho, G R; Hughes, R N; Carter, R E

1992-07-22

108

Quantifying phenotypic gradients in freshwater snails: a case study in Lithasia (Gastropoda: Pleuroceridae)  

Microsoft Academic Search

Many authors have described a pattern of morphological variation in freshwater bivalves where shells taken from lentic and\\u000a lotic environments, or headwaters and main stem reaches, appear to exhibit phenotypic gradients in size and shape. For example,\\u000a mussels taken from headwater reaches tend to possess smooth, less inflated shells compared to the more obese, sculptured individuals\\u000a downstream. Others observed similar

Russell L. Minton; Andrew P. Norwood; David M. Hayes

2008-01-01

109

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

2012-06-04

110

Wide variation in ploidy level and genome size in a New Zealand freshwater snail with coexisting sexual and asexual lineages.  

PubMed

Natural animal populations are rarely screened for ploidy-level variation at a scale that allows detection of potentially important aberrations of common ploidy patterns. This type of screening can be especially important for the many mixed sexual/asexual systems in which sexuals are presumed to be dioecious diploids and asexuals are assumed to be triploid and all-female. For example, elevation of ploidy level above triploidy can be a source of genetic variation and raises the possibility of gene flow among ploidy levels and to asexual lineages. We used flow cytometry and mtDNA sequencing to characterize ploidy level and genome size in Potamopyrgus antipodarum, a New Zealand freshwater snail where obligate sexual (presumed diploid and dioecious) and obligate apomictic asexual (presumed triploid and nearly all female) individuals frequently coexist. We documented the widespread occurrence and multiple origins of polyploid males and individuals with >3× ploidy, and find that both are likely to be descended from asexual females. Our survey also suggested the existence of extensive variation in genome size. The discovery of widespread variation in ploidy level and genome size in such a well-studied system highlights the importance of broad, extensive, and ecologically representative sampling in uncovering ploidy level and genome-size variation in natural populations. PMID:22023586

Neiman, Maurine; Paczesniak, Dorota; Soper, Deanna M; Baldwin, Austin T; Hehman, Gery

2011-06-14

111

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

112

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

PubMed

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

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

2010-10-12

113

Spatial and temporal patterns of parthenogenesis and parasitism in the freshwater snail Melanoides tuberculata.  

PubMed

The Red Queen hypothesis predicts that sex should be more common in populations heavily infested with parasites, than in those without. This hypothesis was investigated in the aquatic snail Melanoides tuberculata, in which both sexual and parthenogenetic individuals exist in natural populations, and some populations are heavily infested by trematodes. The presence of fertile males and the higher genetic diversity of bisexual populations are indicative of sexual reproduction. We compared sites in 1990, 1999, and 2001, and we looked for a positive correlation between male and parasite frequencies. Male frequency was not correlated with the frequency of individuals infected by trematodes. This lack of correlation was reconfirmed in a retrospective power analysis. In a period of 9 years, male frequencies decreased but infection levels increased. These results do not support the Red Queen hypothesis. In samples with high male frequency the number of embryos was low, perhaps indicating that males may have a negative effect on embryo numbers. This effect of males on fitness could perhaps suggest that the cost of sex is fewer embryos. The reduction in embryo numbers may also represent a trade-off between mating and egg production costs. PMID:15669970

Ben-Ami, F; Heller, J

2005-01-01

114

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

2013-07-22

115

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

PubMed

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

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

1983-12-01

116

Population dynamics of Chaetogaster limnaei (Oligochaeta: Naididae) in the field populations of freshwater snails and its implications as a potential regulator of trematode larvae community.  

PubMed

The objectives of this work were to study (1) the population dynamics of Chaetogaster limnaei in the field populations of freshwater snails and the implications for the species as a potential regulator of the trematode larvae community and (2) prevalence and intensity of C. limnaei in relation to host species, host size, and season. This study was conducted at Al-Salam Canal and Al-Abtal village (new cultivated area in north Sinai). The samples were collected from March 2004 to February 2005. The natural infection rate by trematodes and C. limnaei was assessed monthly. Thirteen species of snails were examined for C. limnaei infection, five species were found infected. There were positive correlations between host size and both combined prevalence and mean intensity in all hosts. The data demonstrated that prevalence in Bulinus truncatus was higher when compared with other hosts. Bellamya unicolor has higher mean intensity when compared with other host species. A significant difference was found between host species and both prevalence and intensity. There were spatial and temporal variations in prevalence and mean intensity in most hosts, and the data suggest some seasonality. A negative correlation was found between prevalence of C. limnaei and trematode infection. C. limnaei did not co-occur with trematode larvae in infected hosts indicating that the oligochaete may protect the hosts from trematode infection. B. unicolor was recorded for the first time as a host for C. limnaei. C. limnaei may be a potential regulator of the trematode community in freshwater snails. In conclusion, this study demonstrated that C. limnaei, symbiotically associated with snail vector of parasitic diseases, may have important implications with respect to biological control and/or changes in the epizootiology of native parasites in the study area. PMID:17252272

Ibrahim, Mohamed Moussa

2007-01-25

117

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

PubMed

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

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

2013-02-16

118

Phylogeny, taxonomy, genetics and global heritage ranks of an imperilled, freshwater snail genus Lithasia (Pleuroceridae).  

PubMed

Numerous aquatic species are threatened with extinction from habitat elimination or modification. One particularly imperilled group is the freshwater gastropod family Pleuroceridae. Pleurocerids reach their greatest diversity in the southeastern United States, and many species are currently considered extinct, endangered or threatened. One issue hindering efforts to implement conservation management plans for imperilled pleurocerid species is that the taxonomy is in an abysmal state. The taxonomy of pleurocerids is currently based on late 19th- and early 20th-century studies, which used a typological or morphospecies concept. Most biologists today doubt the validity of many of the currently recognized species; however, this does not stop them from assigning conservation ranks in an attempt to determine which species are imperilled or currently stable. We conducted a phylogenetic analysis of the pleurocerid genus Lithasia using morphological and mitochondrial DNA sequence (mtDNA) data in an attempt to delimit species boundaries and test previous taxonomic schemes. We found that the current taxonomy of Lithasia does not reflect species diversity adequately within the genus, with two new undescribed species being discovered. The conservation status ranks of the new, undescribed species are imperilled and would have been overlooked had we relied on the conventional taxonomy. Additionally, the undescribed species' conservation ranks that were previously apparently secure became vulnerable due to being inappropriately assigned as members of formerly widely distributed species instead of the imperilled status they warrant and vice versa, as some taxa that were considered imperilled are now thought to be modestly stable. Our study suggests that conservation ranks should be considered suspect at best in taxonomically poorly known groups until the taxa are reviewed using modern systematic methods. PMID:12492879

Minton, Russell L; Lydeard, Charles

2003-01-01

119

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

PubMed Central

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 causative agent of PHF. The minimum percentage of Juga spp. harboring the organism in the population studied was 3.5% (2 of 57 snails). No ehrlichia DNA was found in tissues of 123 lymnaeid, physid, and planorbid snails collected at the same site. These data suggest that pleurocerid stream snails may play a role in the life cycle of E. risticii in northern California.

Barlough, Jeffrey E.; Reubel, Gerhard H.; Madigan, John E.; Vredevoe, Larisa K.; Miller, Paul E.; Rikihisa, Yasuko

1998-01-01

120

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

121

Intrahost distribution and transmission of a new species of cyclopoid copepod endosymbiotic to a freshwater snail, Pomacea canaliculata (Caenogastropoda, Ampullariidae), from Argentina.  

PubMed

A new species of cyclopoid copepod, Ozmana huarpium, is described as a symbiont to Pomacea canaliculata (Lamarck 1822) (Caenogastropoda, Ampullariidae). Rather large numbers (about one hundred copepods per snail) were found, although there was no evidence of harm to the host. To our knowledge, O. haemophila (symbiont to P. maculata), and the currently described species, O. huarpium, are the only copepod species ever recorded as endosymbionts to freshwater invertebrates. While O. haemophila is restricted to the haemocoel of its host, O. huarpium predominate in the penis sheath, the ctenidium and the mantle cavity, figuring in these pallial organs 63-65% of total mature forms. The sex ratio of the symbiont is skewed to the female side in these organs, specially in male hosts. The hypothesis that a special female tropism for the male host's pallial organs might ensure interindividual transmission of the symbiont was tested, with indications that the symbiont is mainly transmitted during copulation. PMID:15462567

Gamarra-Luques, C D; Vega, I A; Koch, E; Castro-Vazquez, A

2004-08-01

122

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

2011-11-11

123

Parasite-induced change in host behavior of a freshwater snail: parasitic manipulation or byproduct of infection?  

Microsoft Academic Search

Host behavioral changes due to parasitism are often assumed to be adaptations of the parasite. However, behavioral effects of parasites may be a generalized response to parasitism and only coincidentally beneficial for parasite transmission. For this reason, alternatives to the manipulation hypothesis should be tested. Previous work demonstrated that the trematode parasite Microphallus sp. influences the behavior of the snail

Edward P. Levri

1999-01-01

124

Susceptibility of 7 freshwater gastropod species in Zimbabwe to infection with Gastrodiscus aegyptiacus (Cobbold, 1876) Looss, 1896.  

PubMed

Gastrodiscosis outbreaks due to Gastrodiscus aegyptiacus were recorded in horses in the vicinity of Harare, Zimbabwe, in the absence of Bulinus forskalii, B. senegalensis and Cleopatra sp. which are considered to be the only intermediate host snails. This suggested the possibility of other snail species acting as intermediate hosts in the life cycle of the trematode. A study was carried out to determine the susceptibility of 7 freshwater snail species to infection with G. aegyptiacus. First generation (F-1) of 5 freshwater pulmonate snail species, Bulinus tropicus, Bulinus globosus, Biomphalaria pfeifferi, Helisoma dyuri and Physa acuta that were bred in the laboratory, and 2 prosobranch snail species, Melanoides tuberculata and Cleopatra sp. that were collected from the field were used in this study. Data pertaining to mortalities and cercariae shedding were recorded throughout the experimental period. The prosobranch snails, M. tuberculata and Cleopatra sp. were susceptible to G. aegyptiacus with a minimum prepatent period of 45 days and 54 days, respectively. Bulinus tropicus, P. acuta and H. duryi were susceptible as evidenced by the presence of different generations of rediae and mature cercariae on dissection at 59 days post-infection although attempts to induce the snails to shed from 28 days post-infection did not produce cercariae. Bulinus globosus and Bio. pfeifferi were refractory to infection. The results revealed the ability of G. aegyptiacus to infect M. tuberculata, Cleopatara sp., B. tropicus, P. acuta and H. duryi under experimental conditions and this may explain the recorded outbreaks of gastrodiscosis in equine populations in Zimbabwe in the absence of the known intermediate hosts. Bulinus tropicus is considered as the most likely major intermediate host of G. aegyptiacus because of its wide distribution in Zimbabwe and is well adapted to a wide variety of environments. PMID:15830604

Mukaratirwa, S; Munjere, I F; Takawira, M; Chingwena, G

2004-12-01

125

Adaptive Radiation in the Larval Feeding Habits of the Snail-Killing Fly Genus Tetanocera (Diptera: Sciomyzidae)  

NASA Astrophysics Data System (ADS)

The genus Tetanocera consists of 29 species in North America. The genus is unusual in that its larvae occupy five of the 17 feeding groups recognized in the family, as most other genera of the family occupy only one or two trophic guilds. Seven species have larvae that attack pulmonate aquatic snails, three species attack pulmonate snails stranded on shorelines, four species attack amber snails of the family Succineidae, three species attack slugs, and two species are predators of terrestrial snails. The larval feeding behavior of representative species of each of the five trophic guilds will be described and illustrated.

Foote, B. A.

2005-05-01

126

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

127

Dependence on aerial respiration and its influence on microdistribution in the invasive freshwater snail Pomacea canaliculata (Caenogastropoda, Ampullariidae)  

Microsoft Academic Search

The invasive Neotropical snail Pomacea canaliculata is usually regarded as amphibious, although the relative significance of aerial and aquatic respiration is unknown. To investigate\\u000a the degree of dependence on aerial respiration and its influences on microdistribution, experiments were performed in the\\u000a laboratory and under seminatural and natural conditions. Restriction of aerial respiration negatively affected survivorship,\\u000a activity and feeding, its effects

María E. Seuffert; Pablo R. Martín

2010-01-01

128

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

PubMed

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

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

2013-05-28

129

Isolated Pulmonic Valve Infective Endocarditis: A Persistent Challenge  

Microsoft Academic Search

Isolated pulmonic valve infective endocarditis is an uncommon clinical entity. We report our experience with three patients diagnosed with pulmonic valve endocarditis from our institution. Two cases were caused by Enterococcus faecalis (one was resistant to vancomycin) and one by coagulase-negative staphylococci (CNS). One of the cases of isolated pulmonic valve endocarditis due to the E. faecalis was nosocomially acquired;

N. Hamza; J. Ortiz; R. A. Bonomo

2004-01-01

130

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

2012-11-26

131

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

132

Density-dependent effects of snail grazing on the growth of a submerged macrophyte, Vallisneria spiralis  

Microsoft Academic Search

In order to better understand the role of herbivorous snails in freshwater ecosystems, we conducted experiments investigating food preference of the snail Radix swinhoei on leaves of the submerged plant Vallisneria spiralis with and without periphyton coverage. The effects of snail grazing on the growth of V. spiralis were assessed in a no-snail control and at three snail densities (80,

Kuan-Yi Li; Zheng-Wen Liu; Bin-He Gu

2009-01-01

133

Microsatellite and morphological analysis of population structure in the parthenogenetic freshwater snail Melanoides tuberculata: insights into the creation of clonal variability.  

PubMed

The distribution of variability was studied at various geographical scales in the tropical freshwater snail Melanoides tuberculata, in order to analyse the role of factors shaping this distribution, including the mating system and population dynamics. This parthenogenetic polyploid species reproduces mainly asexually, with males occurring at low frequency. About 800 individuals (38 sites) were sampled from Africa and the Middle East, where the species originated, and from recently colonized habitats in South and Central America, and especially the island of Martinique. We first described variation of general aspects and ornamentation of the shells. This analysis confirms the existence of discrete morphs. Second, individuals were studied at three microsatellite loci, showing that each morph is a genetic clone with some minor variation compatible with models of microsatellite evolution. The genetic analysis also showed much more variation within than between clones. However, two populations from Africa exhibited a large amount of variability, and a mixture of sexual and asexual reproduction might explain these genetic patterns. The worldwide distribution of variability is, therefore, compatible with the African origin of the species, and the introduction of a few clones in other parts of the world. These results also suggest that the distribution of variability in Martinique is influenced by flooding events, and that two morphs from Martinique can be interpreted as hybrids between two pre-existing morphs, based on morphological, genetic and geographical arguments. PMID:10447855

1999-07-01

134

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

2004-12-15

135

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

PubMed

The main purpose of the studies presented in this paper is twofold: 1) to evaluate whether phyto-adaptogens (Acanthopanax senticosus and Rhodiola rosea) are able to exert a protective action against stress-induced death of embryos of the pond snail Lymnaea stagnalis; and 2) whether a possible protective action by phyto-adaptogens can be explained by the induction of heat shock proteins. Enhancement in resistance by phyto-adaptogens was studied by applying plant extracts for a period of 20 hours to 3-day old larvae of the pond snail Lymnaea stagnalis. Subsequently they were exposed to a high and toxic dose of different environmental stressors. The following stress conditions were selected: a physical stress condition (heat shock: 43 degrees C for 4 minutes), an oxidative stress condition (superoxide radicals induced by menadione (600 microM for 2 hours)) and heavy metal-induced stress (copper (150 microM for 1 hour) or cadmium (20 microM during 1 hour)). Both Acanthopanax and Rhodiola exert a strong protective action against a lethal heat shock. These adaptogens also significantly protect against the negative effect of superoxide radicals as induced by menadione. With respect to the protective action against exposure to heavy metals a small but significant protection was observed against intoxication with copper or cadmium by the phyto-adaptogens. In summary, there appears to be a difference in efficiency in enhancing resistance to the various stress conditions used (heat shock>menadione>copper>cadmium). Based on the results presented in this paper, we can conclude that phyto-adaptogens are able to enhance the resistance against the different stress conditions tested in developing individuals of Lymnaea. Although the degree to which resistance is enhanced appears to depend on the type of stressor applied, our results confirm the definition of phyto-adaptogens as being universal enhancers of non-specific resistance against different kinds of stress conditions. With respect to the mechanism of enhanced resistance, the question was asked whether this protective action is caused by an induction of heat shock proteins (hsps), which are known to be involved in tolerance and adaptation. The phyto-adaptogens did not induce the synthesis of any of the hsps, nor did they modulate the normal heat shock induced synthesis of these stress proteins. We conclude that it is unlikely that hsps play a major role in obtaining an enhanced state of resistance provided by phyto-adaptogens. PMID:11081990

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

2000-10-01

136

Endocrine effects of contaminated sediments on the freshwater snail Potamopyrgus antipodarum in vivo and in the cell bioassays in vitro.  

PubMed

Lake Pilnok located in the black coal-mining region Ostrava-Karvina, Czech Republic, contains sediments highly contaminated with powdered waste coal. Moreover, population of the endangered species of narrow-clawed crayfish Pontastacus leptodactylus with high proportion of intersex individuals (18%) was observed at this site. These findings motivated our work that aimed to evaluate contamination, endocrine disruptive potency using in vitro assays and in vivo effects of contaminated sediments on reproduction of sediment-dwelling invertebrates. Chemical analyses revealed low concentrations of persistent chlorinated compounds and heavy metals but concentrations of polycyclic aromatic hydrocarbons (PAH) were high (sum of 16 PAHs 10 microg/g dw). Organic extracts from sediments caused significant in vitro AhR-mediated activity in the bioassay with H4IIE-luc cells, estrogenicity in MVLN cells and anti-androgenicity in recombinant yeast assay, and these effects could be attributed to non-persistent compounds derived from the waste coal. We have also observed significant in vivo effects of the sediments in laboratory experiments with the Prosobranchian euryhaline mud snail Potamopyrgus antipodarum. Sediments from Lake Pilnok as well as organic extracts of the sediments (externally added to the control sediment) significantly affected fecundity during 8 weeks of exposure. The effects were stimulations of fecundity at lower concentrations at the beginning of the experiment followed by inhibitions of fecundity and general toxicity. Our study indicates presence of chemicals that affected endocrine balance in invertebrates, and emphasizes the need for integrated approaches combining in vitro and in vivo bioassays with identification of chemicals to elucidate ecotoxicogical impacts of contaminated sediment samples. PMID:18675471

Mazurová, E; Hilscherová, K; Jálová, V; Köhler, H-R; Triebskorn, R; Giesy, J P; Bláha, L

2008-07-03

137

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 Central

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 Qst–Fst 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 Qst–Fst 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 Qst–Fst) allows disentangling the two effects.

Chapuis, Elodie; Martin, Guillaume; Goudet, Jerome

2008-01-01

138

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

2008-10-14

139

Effect of six non-target snails on Schistosoma mansoni miracidial host finding and infection of Biomphalaria alexandrina under laboratory conditions.  

PubMed

Six snail species naturally associated with Biomphalaria alexandrina, the snail host of Schistosoma mansoni in Egypt, were tested under standard laboratory conditions, for impact on miracidial host findings and infection of the snail host. These snails are the prosobranchs Melanoides tuberculata, Cleopatra bulimoides, Bellamys unicolor and Lanistes carinatus, the pulmonates Planorbis planorbis and Physa acuta. The tested snail ssp. reduced considerably the infection rate of Biomphalaria with S. mansoni especially at a ratio of 10 decoy snails to one Biomphalaria snail. The prosobranchs Melanoides, Cleopatra and Lanistes exhibited more reducing effect on Biomphalaria infection than Bellamya and the pulmonates Physa and Planorbis being 65.2%, 78.8%, 62.9%, 33.3%, 30.3% and 46.9%, respectively. PMID:9707684

Yousif, F; el-Emam, M; el-Sayed, K

1998-08-01

140

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

PubMed

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

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

2003-08-01

141

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

PubMed

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

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

2007-03-01

142

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

143

Factors influencing total haemocyte counts in freshwater gastropods  

Microsoft Academic Search

Total haemocyte counts were made in two freshwater gastropods. Lymnaea acuminata (Lamarck) f. rufescens (Gray), and Indoplanorbis exustus (Deshayes). Influence of age (shell size) was studied in groups of small, intermediate, and large-sized snails; large snails have significantly higher haemocyte counts than intermediate and small snails. Effects of changes in ambient circumstances were studied in medium-sized snails. Decreases in water

P. G. Suresh; M. K. Reju; A. Mohandas

1994-01-01

144

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

145

Prosobranch snails as test organisms for the assessment of endocrine active chemicals--an overview and a guideline proposal for a reproduction test with the freshwater mudsnail Potamopyrgus antipodarum.  

PubMed

Recently, prosobranch snails have been recommended as promising candidates for test organisms for the assessment of endocrine active chemicals. Three prosobranch snail species, the freshwater mudsnail Potamopyrgus antipodarum, the freshwater ramshorn snail Marisa cornuarietis, and the marine netted whelk Nassarius reticulatus are portrayed and their respective biotests are presented together with results of laboratory experiments and biological effect monitoring surveys in the field. All characterized species are highly sensitive toward xeno-androgens [triphenyltin (TPT), tributyltin (TBT), methyltestosterone (MT) and fenarimol (FEN)], and xeno-estrogens [bisphenol A (BPA), octylphenol (OP), ethinylestradiol], and show effects at environmentally relevant, rather low concentrations in laboratory experiments. For exposure to the xeno-androgen TPT, EC(10) values range between 15.9 and 29.0 ng as Sn/L (sediment 0.03 mug as Sn/kg), for TBT, EC(10) values are found between 3.42 and 37.8 ng as Sn/L (sediment 2.98 microg as Sn/kg) and effect concentrations for FEN are calculated as 18.6 ng/L (EC(10)) and 0.19 microg/kg (EC(50) sediment; EC(10) not calculable). Exposure to xeno-estrogens yielded EC(10 )values of 13.9 ng/L (0.19 microg/kg) for BPA, a NOEC of <1 microg/L (EC(10) of 0.004 microg/kg) for OP and a NOEC of 1 ng/l (EC(10) sediment of 2.2 microg/kg) for ethinylestradiol. Responses to androgens comprised the development of imposex and the reduction of fertility or embryo production, effects of estrogens included the stimulation of egg production and embryo production, and the increased weight of glands. Also, biological effect monitoring studies with P. antipodarum and N. reticulatus in several rivers or estuarine areas revealed the capacity of the biotests to detect an androgenic or estrogenic potential of sediment samples. A comparison of the three test species with regard to sensitivity and practical aspects in routine application favors the freshwater mudsnail P. antipodarum for a standardized procedure, and this reproduction test will be introduced into the OECD guideline program for standardization in the near future. PMID:17219090

Duft, Martina; Schmitt, Claudia; Bachmann, Jean; Brandelik, Cornelius; Schulte-Oehlmann, Ulrike; Oehlmann, Jörg

2007-02-01

146

Chronic toxicity of the azaarene quinoline, a synthetic fuel component, to the pond snail Physa gyrina  

Microsoft Academic Search

The azaarene quinoline was tested for chronic toxicity to embryos of the pulmonate snail Physa gyrina. Toxicity criteria were effects on embryogenesis, embryo survival, time to hatching, hatching success, and posthatching survival. Of the controls, 91% hatched, compared with 99, 78, and 5% exposed to 12.5, 25, and 50 mg\\/L of quinoline, respectively. No eggs hatched at or above 100

Raymond E. Millemann; Daniel S. Ehrenberg

1982-01-01

147

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

148

The effect of calcium and pH on Florida apple snail, Pomacea paludosa (Gastropoda: Ampullariidae), shell growth and crush weight  

Microsoft Academic Search

Pomacea (Ampullariidae) snails, commonly referred to as apple snails, serve as prey for many freshwater-dependent predators, and\\u000a some species are highly invasive. Identifying limits to apple snail distribution and abundance are pertinent to understanding\\u000a their ecology. Calcium (Ca2+) availability and pH generally influences freshwater snail populations, yet scant data exist for Pomacea snails. We measured 6-week change in shell length

Nancy H. Glass; Philip C. Darby

2009-01-01

149

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

150

Effects of Self-Fertilization, Environmental Stress and Exposure to Xenobiotics on Fitness-Related Traits of the Freshwater Snail Lymnaea stagnalis  

Microsoft Academic Search

Genetic and ecological factors may interact in their effects on fitness. Such interactions are thus to be expected between\\u000a inbreeding and exposure of a population to a toxicant. The magnitude of inbreeding depression is thought to increase in stressful\\u000a environments. To test this hypothesis, we investigated the combined effects of environmental conditions and inbreeding on\\u000a fitness in the self-fertile snail

Marie-Agnès Coutellec; Laurent Lagadic

2006-01-01

151

Susceptibility of freshwater snails to the amphistome Calicophoron microbothrium and the influence of the species on susceptibility of Bulinus tropicus to Schistosoma haematobium and Schistosoma mattheei infections.  

PubMed

The susceptibility of Bulinus tropicus, B. globosus, Biomphalana pfeifferi, Lymnaea natalensis, and Melanoides tuberculata to Calicophoron microbothrium was examined. Bulinus tropicus had the highest prevalence (65.0%), followed by B. pfeifferi (37.5%), B. globosus (6.8%), and M. tuberculata (5.9%). Lymnaea natalensis was refractory to infection. Bulinus tropicus snails infected with C. microbothrium alone or coinfected with either Schistosoma haematobium or S. mattheei 0, 7, 14, and 21 days after exposure to C. microbothrium produced C. microbothrium cercariae only. PMID:12435124

Chingwena, Givemore; Mukaratirwa, Samson; Kristensen, Thomas K; Chimberi, Moses

2002-10-01

152

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

153

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

154

Molecular and functional characterization of a tandem-repeat galectin from the freshwater snail Biomphalaria glabrata, intermediate host of the human blood fluke Schistosoma mansoni  

PubMed Central

In the present study, a tandem-repeat type galectin was characterized from an embryonic cell line (Bge) and circulating hemocytes of the snail Biomphalaria glabrata, intermediate host of the human blood fluke Schistosoma mansoni. The predicted B. glabrata galectin (BgGal) protein of 32 kDa possessed 2 carbohydrate recognition domains, each displaying 6 of 8 conserved amino acids involved in galactoside-binding activity. A recombinant BgGal (rBgGal) demonstrated hemagglutinating activity against rabbit erythrocytes, which was specifically inhibited by galactose-containing sugars (lacNAc/lac > galNAc/gal). Although native galectin was immunolocalized in the cytoplasm of Bge cells and the plasma membrane of a subset of snail hemocytes (60%), it was not detected in cell-free plasma by Western blot analysis. The findings that rBgGal selectively recognizes the schistosome-related sugar, lacNAc, and strongly binds to hemocytes and the tegument of S. mansoni sporocysts in a sugar-inhibitable fashion suggest that hemocyte-bound galectin may be serving as pattern recognition receptor for this, or other pathogens possessing appropriate sugar ligands. Based on molecular and functional features, BgGal represents an authentic galectin, the first to be fully characterized in the medically-important molluscan Class Gastropoda.

Yoshino, Timothy P.; Dinguirard, Nathalie; Kunert, John; Hokke, Cornelius H.

2008-01-01

155

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

156

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

Microsoft Academic Search

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

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

2009-01-01

157

Cercarial Dermatitis Transmitted by Exotic Marine Snail  

PubMed Central

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

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

2010-01-01

158

Labdane Diterpenes From the South African Marine Pulmonate Trimusculus Costatus  

Microsoft Academic Search

The endemic South African marine pulmonate gastropod Trimusculus costatus yielded two labdane diterpenes, the known 6?,7a-diacetoxylab-8,13-dien-15-ol (1), and the new 2?,6?,7a-triacetoxylabda-8,13-dien-15-ol (2). Standard spectroscopic methods were used to establish the structures of these compounds which were both toxic to Artemia salina and inhibited feeding of the predatory fish Pomadasys commersonnii.

Christopher A. Gray; Michael T. Davies-coleman; Christopher McQuaid

1998-01-01

159

Bron?iyal Yayilim Gösteren Pulmoner Hidatik Kist Olgusu  

Microsoft Academic Search

ÖZET Onüç ya?inda erkek hasta, sik tekrarlayan pulmoner infeksiyon nedeniyle ba?vurdu. Özgeçmi?inde hayvan temasi olma- yan hastanin laboratuvar incelemeleri normaldi. Posteroanterior akci?er grafisinde sol alt lob lokalizasyonuna uyan böl- gede hilus gölgesini silen nispeten düzgün konturlu dansite arti?i vardi. Bilgisayarli toraks tomografisinde sol alt lob loka- lizasyonunda yakla?ik 5 x 6 cm boyutlarinda lezyon tespit edildi. Ayrica alt lob bazal

Mehmet SIRMALI; Ertan AYDIN; Ülkü YAZICI; Ömür AYDIN; Göktürk FINDIK; Sadi KAYA

160

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

Microsoft Academic Search

The freshwater snail Biomphalaria glabrata is closely associated with the transmission of human schistosomiasis. An ecologically sound method has been proposed to control schistosomiasis using genetically modified snails to displace endemic, susceptible ones. To assess the viability of this form of biological control, studies towards understanding the molecular makeup of the snail relative to the presence of endogenous mobile genetic

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

2007-01-01

161

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

PubMed

The influence of non-target freshwater snails (Melanoides tuberculata and Planorbis planorbis) on the capacity of Fasciola egg production F. gigantica miracidia to infect Lymnaea natalensis and their effect on mortality and growth rates showed that the snails exhibited a competitive ability against L. natalensis. The mortality rate existed in mixed cultures with snails was greatly increased, and increased with increase of snails number. The egg production and growth rate were negatively affected by the presence of M. tuberculata and P. planorbis which was more pronounced when snails were at higher ratio lL: 10D. Also, the snails showed significant degree of reduction in infection rate of L. natalensis with F. gigantica miracidia. PMID:17153707

Bakry, Fayez A; Hamdi, Salwa A H

2006-12-01

162

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

163

Aquatic snails of the Bulinus africanus group in Zambia identified according to morphometry and enzymes  

Microsoft Academic Search

The Bulinus africanus species group (Planorbidae) of freshwater snails has been reported to be represented in Zambia by two species, B. africanus (Krauss) and B. globosus (Morelet), both named as intermediate hosts for Schistosoma haematobium. Uncertainty in identification of these snails from morphology led to the present investigation, combining morphometry (shell and copulatory organ) with enzyme analysis. Observations of both

D. S. Brown; D. Rollinson

1996-01-01

164

Environmental impact of the golden snail (Pomacea sp.) on rice farming systems in the Philippines  

Microsoft Academic Search

A summary report of the workshop held at the Freshwater Aquaculture Center, Central Luzon State University, Nueva Ecija, Philippines, on 9-10 November 1989. It discusses the effects wrought by the golden snail since its introduction to the Philippines, particularly on rice farming systems. Ways to control the snail are presented.

B. Acosta; R. S. V. Pullin

165

Evolution of Pulmonate Gastropod Mitochondrial Genomes: Comparisons of Gene Organizations of Euhadra, Cepaea and Albinaria and Implications of Unusual Trna Secondary Structures  

PubMed Central

Complete gene organizations of the mitochondrial genomes of three pulmonate gastropods, Euhadra herklotsi, Cepaea nemoralis and Albinaria coerulea, permit comparisons of their gene organizations. Euhadra and Cepaea are classified in the same superfamily, Helicoidea, yet they show several differences in the order of tRNA and protein coding genes. Albinaria is distantly related to the other two genera but shares the same gene order in one part of its mitochondrial genome with Euhadra and in another part with Cepaea. Despite their small size (14.1-14.5 kbp), these snail mtDNAs encode 13 protein genes, two rRNA genes and at least 22 tRNA genes. These genomes exhibit several unusual or unique features compared to other published metazoan mitochondrial genomes, including those of other molluscs. Several tRNAs predicted from the DNA sequences possess bizarre structures lacking either the T stem or the D stem, similar to the situation seen in nematode mt-tRNAs. The acceptor stems of many tRNAs show a considerable number of mismatched basepairs, indicating that the RNA editing process recently demonstrated in Euhadra is widespread in the pulmonate gastropods. Strong selection acting on mitochondrial genomes of these animals would have resulted in frequent occurrence of the mismatched basepairs in regions of overlapping genes.

Yamazaki, N.; Ueshima, R.; Terrett, J. A.; Yokobori, S. I.; Kaifu, M.; Segawa, R.; Kobayashi, T.; Numachi, K. I.; Ueda, T.; Nishikawa, K.; Watanabe, K.; Thomas, R. H.

1997-01-01

166

Influence of toxic cyanobacteria on community structure and microcystin accumulation of freshwater molluscs  

Microsoft Academic Search

Community structure and microcystin accumulation of freshwater molluscs were studied before and after cyanobacterial proliferations, in order to assess the impact of toxic blooms on molluscs and the risk of microcystin transfer in food web. Observed decrease in mollusc abundance and changes in species richness in highly contaminated waters were not significant; however, relative abundances of taxa (prosobranchs, pulmonates, bivalves)

Claudia Gérard; Virginie Poullain; Emilie Lance; Anthony Acou; Luc Brient; Alexandre Carpentier

2009-01-01

167

Effects of Synthetics molluscicide Niclosamide and plant extracts ( Euphorbia and Melia ) Molluscicide against The different developmental stages of the fresh-water snail physa acuta , the (Draparnaud )vector of trematod parasite in Mosul area North Iraq  

Microsoft Academic Search

The effect of synthetic molluscicide ( Niclosamide) and some botanical molluscicide ( Euphorbia heliscop (EE) and Melia azedirachta (MA)) , of different concentrations on fecundity, survival and embryonic hatchability of the fresh water snails, Physa acuta (Draparnaud) Lymnea auricularia(L)- (pulmonats) and Melanopsis praemorsa (Linnaeus)- (Prosobranchates) in Mosul area were investigated. There are variable lethal effects of different Niclosamide concentrations on

Talib Hussen Ali

168

Methods for conducting snail ( Aplexa hypnorum ) embryo through adult exposures: Effects of cadmium and reduced pH levels  

Microsoft Academic Search

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 bioassays. Exposure of snails from embryos through adult reproductive maturity to cadmium chloride produced delayed hatch, reductions

Gary W. Holcombe; Gary L. Phipps; John W. Marier

1984-01-01

169

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

170

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

171

Repeated naloxone treatments and exposures to weak 60-Hz magnetic fields have 'analgesic' effects in snails.  

PubMed

Results of studies with rodents have shown that animals repeatedly injected with the opioid antagonist, naloxone, acquire a hypoalgesic response to thermal nociceptive stimuli. The present study revealed a similar response in the terrestrial pulmonate snail, Cepaea nemoralis. Snails receiving daily injections of naloxone followed by measurements of thermal nociceptive sensitivity also developed hypoalgesia. Daily brief (30-min) exposures to a weak 60-Hz magnetic field (1.0 gauss or 0.1 mT), which acutely antagonize opioid-mediated nociception and antinociception in a manner comparable to that of naloxone, also led to the expression of a hypoalgesic responses. This suggests that opioid antagonist-induced thermal hypoalgesia may be a basic feature of opioid systems. This naloxone- and magnetic field-induced 'analgesia' is consistent with either a facilitation of aversive thermal conditioning and or antagonism of the excitatory, hyperalgesic effects of low levels of endogenous opioids. PMID:8402190

Kavaliers, M; Ossenkopp, K P

1993-08-20

172

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

Microsoft Academic Search

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

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

2009-01-01

173

Effects of light on the orientation of the snail Physa pomillia in a weak magnetic field  

Microsoft Academic Search

1.The orientation of fresh-water snails (Physa pomillia) in a symmetrical magnetic field was studied from February to March and from September to October, 1965, during the hours 8:30 to 17:30.2.The orientation of the snails was studied in an augmented magnetic field, 9 times that of the earth's field at Gainesville, Florida, with a bar magnet aligned parallel and at right

David G. Badman

1966-01-01

174

Snail herbivory on submerged macrophytes and nutrient release: Implications for macrophyte management  

Microsoft Academic Search

Radix swinhoei (H. Adams) is a freshwater snail commonly found in shallow regions of Lake Taihu. This research estimated, based on experiments, the consumption rates of R. swinhoei on three young submerged plants (Vallisneria spiralis, Hydrilla verticillata and Potamogeton malaianus) and its rates of nutrient release. Results showed that the snails consumed V. spiralis at the highest rate (23.34mgg?1d?1), P.

Kuan-Yi Li; Zheng-Wen Liu; Yao-Hui Hu; Hong-Wei Yang

2009-01-01

175

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

USGS Publications Warehouse

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

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

2012-01-01

176

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)

177

Freshwater Macroinvertebrates.  

ERIC Educational Resources Information Center

|Presents a literature review of freshwater biology particularly freshwater macroinvertebrates and their effect on water pollution, covering publications of 1976-77. A list of 158 references is also presented. (HM)|

Nalepa, T. F.

1978-01-01

178

Free amino acids and osmoregulation in the intertidal pulmonate Onchidium tumidium  

Microsoft Academic Search

The aim of this study is to elucidate the osmoregulatory capabilities of the intertidal pulmonate Onchidium tumidium. Our results indicate that O. tumidium could tolerate hyperosmotic stress more effectively than hypoosmotic stress. In 10% seawater (SW), it was capable of maintaining\\u000a its plasma hyperosmotic and hyperionic to the external medium. However, it rapidly gained weight in 10% SW, and no

S. F. Chew; S. Y. Ho; Y. K. Ip

1999-01-01

179

Comparison of reactive processes in the rat brain elicited by xenotransplantation of nervous tissues of chicken or pulmonate snail  

Microsoft Academic Search

It is known that a histocompatibility system is not developed to the same extent in lower invertebrates as in vertebrate animals. We assumed that the xenografts from the newborn invertebrate nervous system would not exert destructive effects on the brain of the vertebrate recipient even without immunosuppressive therapy. In search of brain xenografts (XG) capable to survive in the brain

Elena V Loseva; Valentin N Vorobyev; Irina V Ermakova; Nadegda N Lermontova; Tiyna G Alekseeva; Igor S Zakharov; Pavel M Balaban

2001-01-01

180

Acyanotic congenital heart disease. Atrial and ventricular septal defects, atrioventricular canal, patent ductus arteriosus, pulmonic stenosis.  

PubMed

This article discusses the four common congenital heart lesions associated with communications between the systemic circulation and the pulmonary circulation, as well as valvular pulmonic stenosis with intact ventricular septum. The incidence and description of each specific anatomical malformation is presented. The clinical findings on physical examination, electrocardiography, chest radiograph, and echocardiography are delineated for each defect. Emphasis is placed on the medical and surgical management and the long-term outcome of such management. PMID:8252562

Mahoney, L T

1993-11-01

181

Shelhigh No-React porcine pulmonic valve conduit: a new alternative to the homograft  

Microsoft Academic Search

Background. The Shelhigh No-React pulmonic valve conduit is a new porcine conduit that is glutaraldehyde-treated and detoxified using a proprietary heparin process. In our institution it has been implanted in 25 patients. The aim of this present contribution is to evaluate the short-term follow-up after its implantation.Methods. From November 1997 to August 1999, 25 patients (mean age, 20.2 years; range,

Stefano M Marianeschi; Gabriele M Iacona; Francesco Seddio; Raul F Abella; Claudia Condoluci; Adriano Cipriani; Fiore S Iorio; Shlomo Gabbay; Carlo F Marcelletti

2001-01-01

182

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

PubMed

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. PMID:22191581

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

2011-12-22

183

Genetic variation in a desert aquatic snail ( Nymphophilus minckleyi ) from Cuatro Ciénegas, Coahuila, Mexico  

Microsoft Academic Search

Nymphophilus minckleyi is a hydrobiid snail endemic to the freshwater spring ecosystem of Cuatro Ciénegas, Mexico. We used seven allozyme loci to examine the genetic substructure of N. minckleyi from 14 sites (subpopulations) in the basin and to test the hypothesis that spring pools in Cuatro Ciénegas are separated into seven hydrologically distinct drainages. Hierarchical F-statistics suggest significant population structure

Angela B. Moline; Stephen M. Shuster; Dean A. Hendrickson; Jane C. Marks

2004-01-01

184

A phylogeny of planorbid snails, with implications for the evolution of Schistosoma parasites  

Microsoft Academic Search

The Planorbidae represent one of the most important families of freshwater snails. They have a wide distribution and are significant both medically and economically as intermediate hosts for trematode worms. Digenetic trematodes of the genus Schistosoma cause schistosomiasis, a disease that infects 200 million people, and domestic animals throughout the tropics. Three of the four recognized species groups of Schistosoma

Jess A. T. Morgan; Randall J. DeJong; Younghun Jung; Khalid Khallaayoune; Sonja Kock; Gerald M. Mkoji; Eric S. Lokera

2002-01-01

185

Molecular phylogeny and biogeography of spring-associated hydrobiid snails of the Great Artesian Basin, Australia  

Microsoft Academic Search

The Great Artesian Basin (GAB) of Australia underlies some of the driest parts of South Australia and Queensland and feeds numerous freshwater springs. Prominent and endangered components of the GAB spring community are snails of the family Hydrobiidae. This paper examines the evolutionary relationships of the entire hydrobiid fauna associated with the GAB, and includes appropriate non-GAB species to place

Kathryn E. Perez; Winston F. Ponder; Donald J. Colgan; Stephanie A. Clark; Charles Lydeard

2005-01-01

186

Fish predation and offspring survival in the prosobranch snail Viviparus ater  

Microsoft Academic Search

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

G. Keller; G. Ribi

1993-01-01

187

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.

Museum, Chicago C.

2011-01-01

188

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

2011-04-13

189

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

190

Spatial mosaic evolution of snail defensive traits  

PubMed Central

Background Recent models suggest that escalating reciprocal selection among antagonistically interacting species is predicted to occur in areas of higher resource productivity. In a putatively coevolved interaction between a freshwater snail (Mexipyrgus churinceanus) and a molluscivorous cichlid (Herichthys minckleyi), we examined three components of this interaction: 1) spatial variation in two putative defensive traits, crushing resistance and shell pigmentation; 2) whether abiotic variables or frequency of molariform cichlids are associated with spatial patterns of crushing resistance and shell pigmentation and 3) whether variation in primary productivity accounted for small-scale variation in these defensive traits. Results Using spatial autocorrelation to account for genetic and geographic divergence among populations, we found no autocorrelation among populations at small geographic and genetic distances for the two defensive traits. There was also no correlation between abiotic variables (temperature and conductivity) and snail defensive traits. However, crushing resistance and frequency of pigmented shells were negatively correlated with molariform frequency. Crushing resistance and levels of pigmentation were significantly higher in habitats dominated by aquatic macrophytes, and both traits are phenotypically correlated. Conclusion Crushing resistance and pigmentation of M. churinceanus exhibit striking variation at small spatial scales often associated with differences in primary productivity, substrate coloration and the frequency of molariform cichlids. These local geographic differences may result from among-habitat variation in how resource productivity interacts to promote escalation in prey defenses.

Johnson, Steven G; Hulsey, C Darrin; de Leon, Francisco J Garcia

2007-01-01

191

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

2012-05-12

192

Investigation of the role of diterpenes produced by marine pulmonates Trimusculus reticulatus and T. conica  

Microsoft Academic Search

The intertidal pulmonate limpetTrimusculus reticulatus, which is found in caves or crevices along the California coast, was previously reported to contain two novel diterpenoids, 6?-isovaleroxylabda-8,13-dien-7?,15-diol (1) and 2?,7?-diacetoxy-6?-isovaleroxylabda-8,13-dien-15-ol (2). Dissection of the animals prior to extraction revealed that the diterpenoids were concentrated in the mantle, foot, and mucus, but not in the viscera. The presence ofT. reticulatus or its mucus

Denise C. Manker; D. John Faulkner

1996-01-01

193

Freshwater Habitats  

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.

194

Biological control of the snail hosts of Schistosoma mansoni in the Caribbean area using Thiara spp.  

PubMed

Field observations and experiments using thiarid snails as competitors of Biomphalaria spp., potential intermediate hosts of Schistosoma mansoni in the Caribbean area, are reviewed. The parthenogenetic snails, Thiara granifera and T. (= Melanoides) tuberculata, were introduced to the Neotropical area in recent decades. In numerous islands and countries, these oriental species have demonstrated their capacity to colonize rapidly and densely many types of habitats while at the same time reducing and even eliminating populations of Biomphalaria spp. The results of field experiments, carried out in several Caribbean islands, have shown the efficiency as well as the limitations of T. tuberculata as a competitor of B. glabrata and B. straminea. In St. Lucia, B. glabrata was apparently eliminated from marshes and streams, 6 to 22 months after the introduction of the competitor. In Martinique, T. tuberculata was introduced into two groups of water-cress beds which constituted the last transmission sites of schistosomiasis on the island. In just less than three years after the introduction of the competitor, both B. glabrata and B. straminea have been eliminated from the transmission sites. In Guadeloupe, several introductions have been carried out in different types of habitat such as permanent ponds, canals, streams and temporary marshes. The findings of all field experiments have indicated that thiarid snails as competitors of pulmonates are favoured by the presence of permanent and stable habitats, preferably shallow, with emergent plants and well oxygenated. On the other hand, the competitor snails are at a disadvantage in waterbodies which are temporary, extremely deep, poorly oxygenated or with a dense mat of floating aquatic vegetation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2566267

Pointier, J P; McCullough, F

1989-05-01

195

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

PubMed Central

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

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

2006-01-01

196

Freshwater Wetlands.  

ERIC Educational Resources Information Center

|Provides descriptions about freshwater wetlands, such as marshes, swamps, and bogs. Contains three learning activities which deal with unusual wetland plants, the animals and plants in a typical marsh, and the effects of a draught on a swamp. Included are reproducible handouts and worksheets for two of the activities. (TW)|

Naturescope, 1986

1986-01-01

197

VARIATION OF SHELL SHAPE IN THE CLONAL SNAIL MELANOIDES TUBERCULATA AND ITS CONSEQUENCES FOR THE INTERPRETATION OF FOSSIL SERIES  

Microsoft Academic Search

Interpreting paleontological data is difficult because the genetic nature of observed morphological variation is generally unknown. Indeed, it is hardly possible to distinguish among several sources of morphological variation including phenotypic plasticity, sexual dimorphism, within-species genetic variation or differences among species. This can be addressed using fossil organisms with recent representatives. The freshwater snail Melanoides tuberculata ranks in this category.

Sarah Samadi; Patrice David; Philippe Jarne

2000-01-01

198

Control of the Snail Hosts of Schistosomiasis by Environmental Manipulation A Field and Laboratory Appraisal in the Ibadan Area, Nigeria  

Microsoft Academic Search

An account is given of an ecological investigation of freshwater habitats near Ibadan, Nigeria, which was designed to identify and evaluate key factors that might be manipulated to achieve control of the snail hosts of schistosomiasis and fascioliasis. Statistical analyses of data from 24 stations from both lentic and lotic habitats showed that there were statistically significant tendencies for the

J. D. Thomas; A. I. Tait

1984-01-01

199

Methods for Conducting Snail (Aplexa hypnorum) Embryo through Adult Exposures: Effects of Cadmium and Reduced pH Levels.  

National Technical Information Service (NTIS)

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 sys...

G. W. Holcombe G. L. Phipps J. W. Marier

1984-01-01

200

Permeability barrier in the mantle epithelium lining the testis in the apple-snail Pomacea canaliculata (GASTROPODA: AMPULLARIIDAE)  

Microsoft Academic Search

Intercellular junctions are studied in the epithelium lining the testis of the freshwater snailPomacea canaliculata by conventional staining and lanthanum tracer techniques. The junctional complex consists of belt desmosomes and septate junctions. Septate junctions are of the pleated-sheet type and they are constantly associated with mitochondria. Gap and tight junctions appear to be absent. These septate junctions seem to be

E. A. Albrecht; J. C. Cavicchia

2001-01-01

201

Variation in the population dynamics of the intertidal pulmonate gastropod Salinator solida Martens (Gastropoda: Amphibolidae) at Towra Point, NSW, Australia  

Microsoft Academic Search

This paper describes variation in the population dynamics of the intertidal pulmonate gastropod solida among mangrove and saltmarsh habitats at Towra Point, NSW, Australia over a two-year period. In general, this paper describes the degree to which the density of the populations fluctuated and the size structure of the populations varied among heights on shore. The density of individuals in

A. C. Roach; R. P. Lim

2000-01-01

202

Impacts of an Invasive Snail (Tarebia granifera) on Nutrient Cycling in Tropical Streams: The Role of Riparian Deforestation in Trinidad, West Indies  

PubMed Central

Non-native species and habitat degradation are two major catalysts of environmental change and often occur simultaneously. In freshwater systems, degradation of adjacent terrestrial vegetation may facilitate introduced species by altering resource availability. Here we examine how the presence of intact riparian cover influences the impact of an invasive herbivorous snail, Tarebia granifera, on nitrogen (N) cycling in aquatic systems on the island of Trinidad. We quantified snail biomass, growth, and N excretion in locations where riparian vegetation was present or removed to determine how snail demographics and excretion were related to the condition of the riparian zone. In three Neotropical streams, we measured snail biomass and N excretion in open and closed canopy habitats to generate estimates of mass- and area-specific N excretion rates. Snail biomass was 2 to 8 times greater and areal N excretion rates ranged from 3 to 9 times greater in open canopy habitats. Snails foraging in open canopy habitat also had access to more abundant food resources and exhibited greater growth and mass-specific N excretion rates. Estimates of ecosystem N demand indicated that snail N excretion in fully closed, partially closed, and open canopy habitats supplied 2%, 11%, and 16% of integrated ecosystem N demand, respectively. We conclude that human-mediated riparian canopy loss can generate hotspots of snail biomass, growth, and N excretion along tropical stream networks, altering the impacts of an invasive snail on the biogeochemical cycling of N.

Moslemi, Jennifer M.; Snider, Sunny B.; MacNeill, Keeley; Gilliam, James F.; Flecker, Alexander S.

2012-01-01

203

Effects of serotonin, dopamine and ergometrine on locomotion in the pulmonate mollusc Helix lucorum.  

PubMed

The terrestrial snail Helix lucorum crawls using waves of muscular contraction (pedal waves) that spread along the sole of its foot. Crawling speed depends on wave generation frequency (step frequency) and the distance the snail moves forwards during each wave (step length). In a previous study, video recordings of a crawling snail showed that its sole length varied over a wide range and was directly correlated with mollusc speed. Speed depended on step length, which was directly related to sole length, rather than on step frequency, which remained rather constant. In the present study, the effects of dopamine, ergometrine (a blocker of dopamine receptors in molluscs) and serotonin injection on the linear relationship between sole length and locomotor speed in Helix lucorum were studied. In crawling snails, dopamine caused sole contraction, and locomotion slowed down or ceased. Ergometrine stimulated locomotion, which resembled rapid crawling with an extended sole, as observed under normal conditions. Serotonin stimulated locomotion and accelerated crawling significantly without causing changes in sole length. The acceleration of locomotion induced by serotonin injection was due to pedal wave (step) elongation. It is proposed that, during each locomotor episode, dopamine controls snail speed by regulating sole length, which determines the amplitude of contraction of the muscle cells involved in pedal waves and, as a result, step length; serotonin determines the basic step length and shifts the linear relationship between sole length and mollusc speed upwards along the axis of mollusc speed. The efficiency of the serotonergic system depends on the physiological state of the mollusc (e.g. that characteristic of summer or winter). PMID:11398751

Pavlova, G A

2001-05-01

204

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

205

Nuclear Sex-determining Genes Cause Large Sex Ratio Variation in the Apple Snail  

Microsoft Academic Search

ABSTRACT Evolutionary maintenance,of genetic sex-ratio variation is enigmatic since genes for biased sex ratios are disadvantageous in finite populations (the “Verner effect”). However, such variation could be maintained if a small number,of nuclear sex-determining genes are responsible, although this has not been fully demonstrated experimentally. Brood sex ratios of a freshwater snail Pomacea canaliculataare highly variable among parents, but population

Pomacea Canaliculata; Yoichi Yusa

206

Antidepressants cause foot detachment from substrate in five species of marine snail.  

PubMed

Active Pharmaceutical Ingredients (APIs) are released into aquatic ecosystems through discharged sewage wastewater. Antidepressants are among those APIs often detected in wastewater effluent and have been recently reported to cause foot detachment from the substrate in freshwater snails. We tested the effects of four commonly prescribed antidepressants {fluoxetine ("Prozac"), fluvoxamine ("Luvox"), venlafaxine ("Effexor"), and citalopram ("Celexa") on adhesion to the substrate in five species of marine snails, three from the Pacific coast (Chlorostoma funebralis, Nucella ostrina, Urosalpinx cinerea) and two species from the Atlantic coast (Tegula fasciatus and Lithopoma americanum) of North America representing three different gastropod families. All antidepressants tested induced foot detachment from the substrate in all snail species in a mainly dose-dependent manner (p < 0.04-0.00000001). The lowest LOECs (lowest observed effect concentration) for antidepressants and snails were recorded for Lithopoma in 43.4 ?g/L (100 nM) fluvoxamine and Chlorostoma in 157 ?g/L (500 nM) venlafaxine and 217 ?g/L (500 nM) fluvoxamine. The trochids and turbinids were 2-10× more sensitive to the antidepressants than the muricids. Latency to detachment was also dose dependent, with the fastest average times to detach seen in Chlorostoma and Lithopoma (7.33 and 13.16 min respectively in 3.13 mg/L venlafaxine). The possible physiological mechanisms regulating antidepressant-induced foot detachment in marine snails and the possible ecological consequences are discussed. PMID:23218553

Fong, Peter P; Molnar, Nikolett

2012-11-23

207

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

208

Monoamines in the pedal plexus of the land snail Megalobulimus oblongus (Gastropoda, Pulmonata).  

PubMed

In molluscs, the number of peripheral neurons far exceeds those found in the central nervous system. Although previous studies on the morphology of the peripheral nervous system exist, details of its organization remain unknown. Moreover, the foot of the terrestrial species has been studied less than that of the aquatic species. As this knowledge is essential for our experimental model, the pulmonate gastropod Megalobulimus oblongus, the aim of the present study was to investigate monoamines in the pedal plexus of this snail using two procedures: glyoxylic acid histofluorescence to identify monoaminergic structures, and the unlabeled antibody peroxidase anti-peroxidase method using antiserum to detect the serotonergic component of the plexus. Adult land snails weighing 48-80 g, obtained from the counties of Barra do Ribeiro and Charqueadas (RS, Brazil), were utilized. Monoaminergic fibers were detected throughout the pedal musculature. Blue fluorescence (catecholamines, probably dopamine) was observed in nerve branches, pedal and subepithelial plexuses, and in the pedal muscle cells. Yellow fluorescence (serotonin) was only observed in thick nerves and in muscle cells. However, when immunohistochemical methods were used, serotonergic fibers were detected in the pedal nerve branches, the pedal and subepithelial plexuses, the basal and lateral zones of the ventral integument epithelial cells, in the pedal ganglion neurons and beneath the ventral epithelium. These findings suggest catecholaminergic and serotonergic involvement in locomotion and modulation of both the pedal ganglion interneurons and sensory information. Knowledge of monoaminergic distribution in this snail s foot is important for understanding the pharmacological control of reflexive responses and locomotive behavior. PMID:15264012

Faccioni-Heuser, M C; Zancan, D M; Achaval, M

2004-06-22

209

Premature failure of small-sized Shelhigh No-React porcine pulmonic valve conduit model NR4000  

Microsoft Academic Search

Objective: Given the limited availability of small-sized cryopreserved pulmonary homografts, we implanted a series of Shelhigh No-React porcine pulmonic valve conduits (SPVC). The aim of this study was to evaluate the short-term performance following implantation. Methods: From February 2000 to September 2000, the SPVC was implanted 25 times in 24 patients in the right ventricular outflow tract (RVOT) to correct

Toru Ishizaka; Richard G. Ohye; Caren S. Goldberg; Stephen R. Ramsburg; Takaaki Suzuki; Eric J. Devaney; Edward L. Bove

2003-01-01

210

Freshwater Flow Charts - 1995  

SciTech Connect

This report covers the following: (1) Explanation of Charts Showing Freshwater Flow in 1995; (2) Estimated U.S. Freshwater Flow in 1995 (chart); (3) Estimated California Freshwater Flow in 1995 (chart); (4) Estimated New Mexico Freshwater Flow in 1995 (chart); and (5) Web locations and credits.

Kaiper, G V

2003-11-21

211

Regulated bradycardia in the pulmonate limpet Siphonaria (Gastropoda: Mollusca) during pollutant exposure: implication for biomarker studies.  

PubMed

Although the cardiac activity of invertebrates is now widely used as a biomarker of marine pollution, few studies consider the intrinsic factors causing the variability of heart rate (HR), including the physiological states associated with metabolic depression and behavioural isolation. We examined the cardiac responses to copper exposure of a pulmonate limpet (Siphonaria capensis Quoy and Gaimard), known to adaptively depress heart rate (and metabolic rate) under naturally stressful conditions (hyposalinity). Analysis of variance was used to assess the effects of copper concentration (0-1000 microg/L), exposure time (0-2 h), and individual difference (eight limpets per concentration) on heart rate parameters. Minute by minute heart rate (HR) and heart rate variability (HRV), and bradycardia (< or =10 beats/min) were determined from continuous recording traces. Most of the HR variance was attributable to the interaction of concentration and individuals (35.8%). Considerably lower mean HRs for the higher range of copper concentrations (250 to 1000 microg/L), compared to the lower range (0 to 50 microg/L), were attributable to the virtually exclusive induction of bradycardia in the higher concentration treatments. With increasing concentration, bradycardia was induced sooner and became less interspersed with near normal heart rates (i.e., less episodic). This regulated bradycardial response is apparently associated with isolation (avoidance) behaviour rather than with copper uptake. These findings have implications for biomarker exercises which use heart rate, in cases where invertebrates depress metabolism. PMID:15556386

Marshall, David J; Peter, Ryan; Chown, Steven L

2004-11-01

212

Terrestrial snails use predator-diet to assess danger  

Microsoft Academic Search

Some aquatic snails are able to use chemical cues (kairomones) to differentiate between predators that have fed on snails and predators that have eaten other prey. However, it is unknown if terrestrial snails are able to differentiate between snail-fed predators and predators that have not recently consumed snails. Here we document diet-based chemical discrimination of a predator, the ground beetle

Hugh Lefcort; Frida Ben-Ami; Joseph Heller

2006-01-01

213

Effects of temperature on food ingestion rate and absorption, retention, and equilibrium burden of phosphorus in an aquatic snail, Goniobasis clavaeformis Lea  

Microsoft Academic Search

The effects of sublethal temperatures on feeding rates and phosphorus dynamics of a freshwater snail, Goniobasis clavaeformis Lea, were determined and feeding rates were measured at four temperatures. The food source was aufwuchs labelled with radioactive phosphorus. A model was developed to elucidate the results of this type of study. Food ingestion rate increased with increasing temperature up to 14°C

J. W. Elwood; R. A. Goldstein

1975-01-01

214

Factors affecting the distribution and abundance of the commensal Temnocephala iheringi (Platyhelminthes: Temnocephalidae) among the southernmost populations of the apple snail Pomacea canaliculata (Mollusca: Ampullariidae)  

Microsoft Academic Search

Temnocephala iheringi is the most common temnocephalan inhabiting the mantle cavity of the apple snail Pomacea canaliculata, a freshwater neotropical gastropod that has become a serious rice pest in Southeastern Asia. T. iheringi has been recorded from Mato Grosso (Brazil) to water bodies associated with the Río de la Plata river (Argentina). During an extensive survey in the southern limit

Pablo R. Martín; Alejandra L. Estebenet; Silvana Burela

2005-01-01

215

Cardiovascular effects of right ventricle-pulmonary artery valved conduit implantation in experimental pulmonic stenosis.  

PubMed

Right ventricle (RV)-pulmonary artery (PA) valved conduit (RPVC) implantation decreases RV systolic pressure in pulmonic stenosis (PS) by forming a bypass route between the RV and the PA. The present study evaluates valved conduits derived from canine aortae in a canine model of PS produced by pulmonary artery banding (PAB). Pulmonary stenosis was elicited using PAB in 10 conditioned beagles aged 8 months. Twelve weeks after PAB, the dogs were assigned to one group that did not undergo surgical intervention and another that underwent RPVC using denacol-treated canine aortic valved grafts (PAB+RPVC). Twelve weeks later, the rate of change in the RV-PA systolic pressure gradient was significantly decreased in the PAB+RPVC, compared with the PAB group (60.5 +/- 16.7% vs. 108.9 +/- 22.9%; p<0.01). In addition, the end-diastolic RV free wall thickness (RVFWd) was significantly reduced in the PAB+RPVC, compared with the PAB group (8.2 +/- 0.2 vs. 9.4 +/- 0.7 mm; p<0.05). Thereafter, regurgitation was not evident beyond the conduit valve and the decrease in RV pressure overload induced by RPVC was confirmed. The present results indicate that RPVC can be performed under a beating heart without cardiopulmonary bypass and adapted to dogs with various types of PS, including "supra valvular" PS or PS accompanied by dysplasia of the pulmonary valve. Therefore, we consider that this method is useful for treating PS in small animals. PMID:19420852

Saida, Yuuto; Tanaka, Ryou; Fukushima, Ryuji; Hoshi, Katsuichiro; Hira, Satoshi; Soda, Aiko; Iizuka, Tomoya; Ishikawa, Taisuke; Nishimura, Taiki; Yamane, Yoshihisa

2009-04-01

216

A NOTE ON THE EFFECTS OF DRASTIC CHANGES IN TOTAL DISSOLVED SOLIDS ON THE AQUATIC PULMONATE SNAIL BULINUS (PHYSOPSIS) AFRICANUS KRAUSS  

Microsoft Academic Search

THE transfer of a sample of Bulinus (Physopsis) africanus from water in their natural habitat containing 490 ppm TDS to a laboratory culture medium of 126 ppm TDS was found to be accompanied by a marked increase in the variability of the rate of oxygen consumption among individuals, and resulted in a 46% mortality. Transfer through the same gradient, but

J. HEEG

1975-01-01

217

Snail sperm production characteristics vary with sperm competition risk  

PubMed Central

Sperm competition is widespread and influences both male investment in spermatogenic tissue and ejaculate characteristics. Sperm competition models assume trade-offs between sperm size and number, although such trade-offs may be difficult to detect. This study examines the effects of sperm competition risk on the sperm production characteristics of the freshwater snail Viviparus ater. In this prosobranch, females mate frequently and store sperm, generating sperm competition. Males produce two sperm morphs, fertile eupyrene sperm and non-fertilizing oligopyrene sperm. Non-fertilizing sperm may play a role in sperm competition and therefore, like fertilizing sperm, the number produced could vary relative to sperm competition risk. In addition, trade-offs between sperm number and sperm size may be expected. We manipulated the sex ratio of sexually mature snails and found the presence of rivals affected the ratio of oligopyrene/eupyrene sperm males produced. In experimental and natural populations, the number of oligopyrene sperm produced, but not the number of eupyrene sperm, was significantly higher when the sex ratio was male biased. Testis mass did not vary between experimental treatments. We also found a negative relationship between the number and size of oligopyrene sperm produced, which is consistent with evolutionary models of sperm competition, and is, to our knowledge, the first intraspecific demonstration of a trade-off between these traits.

Oppliger, A.; Hosken, D. J.; Ribi, G.

1998-01-01

218

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

SciTech Connect

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

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

1997-05-01

219

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

NASA Astrophysics Data System (ADS)

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

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

2003-04-01

220

Atrazine does not affect algal biomass or snail populations in microcosm communities at environmentally relevant concentrations.  

PubMed

The herbicide atrazine is a photosynthetic inhibitor used around the world in agricultural applications. Contamination of surface waters adjacent to treated areas can directly reduce growth of nontarget aquatic autotrophs, but the severity of impacts is highly dependent on species sensitivity and exposure concentration. Secondary effects resulting from macrophyte or phytoplankton decline may include an expansion of the more tolerant periphyton community. Recently, this shift in the autotrophic community has been proposed as a mechanism for increased rates of parasite infections in amphibians via augmented populations of aquatic snails which act as intermediate hosts to larval trematodes. To further clarify this relationship, an outdoor microcosm study was conducted to examine the effects of atrazine on primary production and snail populations over a range of environmentally relevant concentrations. In July 2009, 15 experimental ponds were treated to achieve initial concentrations of 0, 1, 10, 30, and 100 µg/L atrazine. Over a period of 73 d, measures were taken of macrophyte, phytoplankton, and periphyton biomass, growth, and fecundity of caged snails (Physella spp. and Stagnicola elodes) and free-living snails (Physella spp.). Except for declines in macrophyte biomass at the highest treatment level, no consistent relationships were found between atrazine concentration and any measured parameter. Comparison of these results with previous findings highlights the variability of responses to atrazine exposure between similarly constructed freshwater communities, even at concentrations up to 20 times higher than sustained environmental levels. PMID:21567448

Baxter, Leilan R; Moore, Dana L; Sibley, Paul K; Solomon, Keith R; Hanson, Mark L

2011-05-12

221

THE IONIC BASIS OF THE RESTING POTENTIAL IN A CROSS-STRIATED MUSCLE OF THE AQUATIC SNAIL LYMNAEA STAGNALIS  

Microsoft Academic Search

SUMMARY The mean resting potential in the heart ventricle muscle cells of the freshwater snail Lymnaea stagnalis was found to be —61-2 ± 3*5 (..) mV (ranging from — 56mV to — 68mV). The average intracellular potassium concentration was estimated to be 51 -5 ± 14-6 (..) m (ranging from 27-8 m to 77-3 m). The membrane of the heart

B. L. BREZDEN; D. R. GARDNER

1984-01-01

222

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

223

Alarm response of hatchlings of the apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae), to aqueous extracts of other individuals  

Microsoft Academic Search

We examined how hatchlings of the freshwater snail, Pomacea canaliculata, responded to aqueous extracts of conspecific hatchlings. Three, 3-day-old hatchlings were macerated in deionized water (1?mg hatchling per 1?ml water). When 0.5?ml of the aqueous extract was added to a test tube containing 10 hatchlings of the same age and 50?ml of water, the hatchlings in the water began to

Katsuya Ichinose; Yoichi Yusa; Kazuhiro Yoshida

2003-01-01

224

Celss nutrition system utilizing snails  

NASA Astrophysics Data System (ADS)

At the 40th IAF Congress in Malaga, a nutrition system for a lunar base CELSS was presented. A lunar base with a total of eight crew members was envisaged. In this paper, four species of plants—rice, soybean, lettuce and strawberry—were introduced to the system. These plants were sufficient to satisfy fundamental nutritional needs of the crew members. The supply of nutrition from plants and the human nutritional requirements could almost be balanced. Our study revealed that the necessary plant cultivation area per crew member would be nearly 40 m 3 in the lunar base. The sources of nutrition considered in the study were energy, sugar, fat, amino acids, inorganic salt and vitamins; however, calcium, vitamin B 2, vitamin A and sodium were found to be lacking. Therefore, a subsystem to supply these elements is of considerable value. In this paper, we report on a study for breeding snails and utilizing meat as food. Nutrients supplied from snails are shown to compensate for the abovementioned lacking elements. We evaluate the snail breeder and the associated food supply system as a subsystem of closed ecological life support system.

Midorikawa, Y.; Fujii, T.; Ohira, A.; Nitta, K.

225

Fungal farming in a snail.  

PubMed

Mutualisms between fungi and fungus-growing animals are model systems for studying coevolution and complex interactions between species. Fungal growing behavior has enabled cultivating animals to rise to major ecological importance, but evolution of farming symbioses is thought to be restricted to three terrestrial insect lineages. Surveys along 2,000 km of North America's Atlantic coast documented that the marine snail Littoraria irrorata grazes fungus-infected wounds on live marsh grass throughout its range. Field experiments demonstrate a facultative, farming mutualism between Littoraria and intertidal fungi. Snails graze live grass primarily not to feed but to prepare substrate for fungal growth and consume invasive fungi. Fungal removal experiments show that snails and fungi act synergistically to suppress marsh grass production. These results provide a case of fungus farming in the marine environment and outside the class Insecta and reveal a previously undemonstrated ecological mechanism (i.e., facilitation of fungal invasion) by which grazers can exert top-down control of marine plant production. PMID:14657360

Silliman, Brian R; Newell, Steven Y

2003-12-04

226

Fungal farming in a snail  

PubMed Central

Mutualisms between fungi and fungus-growing animals are model systems for studying coevolution and complex interactions between species. Fungal growing behavior has enabled cultivating animals to rise to major ecological importance, but evolution of farming symbioses is thought to be restricted to three terrestrial insect lineages. Surveys along 2,000 km of North America's Atlantic coast documented that the marine snail Littoraria irrorata grazes fungus-infected wounds on live marsh grass throughout its range. Field experiments demonstrate a facultative, farming mutualism between Littoraria and intertidal fungi. Snails graze live grass primarily not to feed but to prepare substrate for fungal growth and consume invasive fungi. Fungal removal experiments show that snails and fungi act synergistically to suppress marsh grass production. These results provide a case of fungus farming in the marine environment and outside the class Insecta and reveal a previously undemonstrated ecological mechanism (i.e., facilitation of fungal invasion) by which grazers can exert top-down control of marine plant production.

Silliman, Brian R.; Newell, Steven Y.

2003-01-01

227

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

228

Snail modulates cell metabolism in MDCK cells.  

PubMed

Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP(+)-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of key enzymes. This results in enhanced glucose dependency and leads to cell death under low-glucose conditions. On the other hand, the reduced requirements for oxygen and nutrients from the surrounding environment, might confer the resistance to cell death induced by hypoxia and malnutrition. PMID:23438434

Haraguchi, Misako; Indo, Hiroko P; Iwasaki, Yasumasa; Iwashita, Yoichiro; Fukushige, Tomoko; Majima, Hideyuki J; Izumo, Kimiko; Horiuchi, Masahisa; Kanekura, Takuro; Furukawa, Tatsuhiko; Ozawa, Masayuki

2013-02-21

229

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

230

Inquiry, Land Snails, and Environmental Factors  

ERIC Educational Resources Information Center

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

Barrow, Lloyd H.; Krantz, Patrick D.

2005-01-01

231

Phylogenomics supports Panpulmonata: Opisthobranch paraphyly and key evolutionary steps in a major radiation of gastropod molluscs.  

PubMed

Pulmonates, with over 30,000 described species, represent the largest radiation of non-marine animals outside of Arthropoda. The pulmonate lung was a key evolutionary innovation enabling diversification of terrestrial and freshwater snails and slugs. However, recent studies drew conflicting conclusions about pulmonate monophyly, and support for a sister group is lacking, hindering our understanding of this major animal radiation. Analyses of mitochondrial protein-coding genes recovered a paraphyletic Pulmonata grading into a monophyletic Opisthobranchia, a traditional group of sea slugs long considered sister to pulmonates. Conversely, analyses of datsets dominated by nuclear rDNA indicated Opisthobranchia is paraphyletic with respect to Pulmonata. No study resolved the placement of two key taxa: Sacoglossa, an opisthobranch group including photosynthetic sea slugs, and Siphonarioidea, intertidal limpet-like snails traditionally in Pulmonata. To examine evolutionary relationships at the base of the pulmonate radiation, we performed a phylogenomic analysis of 102 nuclear protein-coding gene regions for 19 gastropods. Opisthobranchia was recovered as paraphyletic with respect to Panpulmonata, a clade in which Sacoglossa was sister to Pulmonata, with Siphonarioidea as the basal pulmonate lineage. Siphonarioideans share a similar gill structure with shelled sacoglossans but lack the contractile pneumostome of pulmonates, suggesting descent from an evolutionary intermediate that facilitated the pulmonate radiation into non-marine habitats. PMID:23850501

Kocot, Kevin M; Halanych, Kenneth M; Krug, Patrick J

2013-07-10

232

Can snails ever be effective and safe biocontrol agents?  

Microsoft Academic Search

The use of snails as biocontrol agents against other snails and against aquatic weeds is reviewed, evaluating their success and their impacts on non-target organisms. The predatory snail Euglandina rosea (and other species), although widely used against Achatina fulica (the giant African land snail) on Pacific and Indian Ocean islands, has not been shown to control A. fulica but has

Robert H. Cowie

2001-01-01

233

Bacterial flora of the schistosome vector snail Biomphalaria glabrata.  

PubMed Central

The aerobic heterotrophic bacterial flora in over 200 individuals from 10 wild populations and 3 laboratory colonies of the schistosome vector snail Biomphalaria glabrata was examined. Internal bacterial densities were inversely proportional to snail size and were higher in stressed and laboratory-reared snails. The numerically predominant bacterial genera in individual snails included Pseudomonas, Acinetobacter, Aeromonas, Vibrio, and several members of the Enterobacteriaceae. Enterobacteriaceae seldom predominated in laboratory colonies. Our data suggest that Vibrio extorquens and a Pasteurella sp. tend to predominate in high-bacterial-density snails. These snails may be compromised and may harbor opportunistic snail pathogens.

Ducklow, H W; Boyle, P J; Maugel, P W; Strong, C; Mitchell, R

1979-01-01

234

[Prevalence of heart murmurs, aortic and pulmonic stenosis in boxers presented for pre-breeding exams in Switzerland].  

PubMed

Boxer are predisposed to subaortic (SAS) and pulmonic stenosis (PS). To decrease the prevalence, pre-breeding cardiologic exams were performed in the last years. In our study the results of 309 pre-breeding exams of boxers presented between 1999 and 2008 were evaluated retrospectively. The overall prevalence of heart murmurs was 26.5 %. A SAS was diagnosed in 25 (8.1 %) and a PS in 10 (3.3 %) dogs. A combination of both defects was found in 7 (2.3 %) Boxers. Animals with a heart murmur of at least grade 3/6 had a significantly higher peak aortic flow velocity (VmaxAo) than animals without or only soft heart murmurs. Over the study period both the frequency of heart murmurs and diagnosis of SAS and PS decreased. PMID:20582897

Höpfner, R; Glaus, T; Gardelle, O; Amberger, C; Glardon, O; Doherr, M G; Lombard, C W

2010-07-01

235

Life history of Allocreadium handiai Pande, 1937 (Trematoda: Allocreadiidae) from the freshwater fish Channa punctata bloch  

Microsoft Academic Search

The life history ofAllocreadium handiai, found in the intestine of the freshwater fishChanna punctata, has been elucidated experimentally. The miracidia develop and hatch from the eggs in 7 to 12 days. The operculate snailAlocinma travancorica acts as the first intermediate host, inside which the miracidium develops through two generations of rediae. The ophthalmoxiphidiocercous cercariae escape fromA. travancorica and encyst in

R. Madhavi

1980-01-01

236

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

237

[Immunity in parasite-vector snails].  

PubMed

Aquatic snails play a key role in the transmission of parasites such as the human blood or liver flukes (Schistosomes and Fasciola sp.). During the last decade, particular efforts have been made by a small number of scientists to progress in our understanding of the molecular mechanisms underlying snail immune responses and/or host parasite interactions. Complementary approaches using the gastropod snail Biomphalaria glabrata, an intermediate host of Schistosoma mansoni, have yielded a number of unexpected results such as the existence of highly diversified pathogen-binding proteins (FREPs), or potential immune regulators similar to mammalian cytokines. Although molecular immune processes largely remain to be elucidated, accumulating data support the idea that snail innate immunity is much more complex than originally thought. PMID:19409193

Coustau, Christine

2009-04-01

238

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

PubMed

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

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

2013-06-01

239

Effects of the herbicide atrazine's metabolites on host snail mortality and production of trematode cercariae.  

PubMed

Environmental stressors have the potential to greatly impact the transmission of parasites with complex, multi-host life cycles such as those of trematodes. The commonly used herbicide atrazine has been shown to affect the susceptibility of second intermediate hosts (such as larval amphibians) to trematode infection, as well as the longevity and infectivity of the free-swimming cercariae, but not eggs or the free-swimming miracidia that infect the gastropod first intermediate hosts. However, we do not know if this pesticide influences the survival of infected snails or whether it affects cercariae production within, or emergence from, these hosts. In addition, previous studies of host-parasite dynamics have only examined the parent atrazine compound, not any of the long-lasting metabolites commonly present in water bodies. Here, we report that a concentration of 0.33 µg/L of an atrazine metabolite, desethyl atrazine, increased the mortality of freshwater gastropods ( Stagnicola elodes ) infected with a gymnocephalus type of cercaria but not that of uninfected snails or those harboring a mature or dormant infection of Echinoparyphium sp. In contrast, 2 wk of exposure to desethyl atrazine did not affect the emergence of gymnocephalus cercariae from snails, although a trend for a decrease in the emergence of Echinoparyphium sp. cercariae was observed. We suggest that simultaneous trematode infection and exposure to contaminants may represent a significant combined stress to gastropods, but this is likely parasite species-specific as well as dependent on whether cercariae are being actively produced. PMID:21554070

Koprivnikar, Janet; Walker, Patrick A

2011-05-09

240

Induced chemical defenses in a freshwater macrophyte suppress herbivore fitness and the growth of associated microbes.  

PubMed

The freshwater macrophyte Cabomba caroliniana induces a chemical defense when attacked by either the crayfish Procambrus clarkii or the snail Pomacea canaliculata. Induction by either consumer lowers the palatability of the plant to both consumers. When offered food ad libitum, snails feeding on non-induced C. caroliniana grew 2.6-2.7 times more than those feeding on induced C. caroliniana. Because snails fed less on induced plants, this could be a behavioral effect (reduced feeding), a physiological effect of the induced metabolites on the consumer, or both. To assess these possibilities, we made artificial diets with lipid extracts of induced versus non-induced C. caroliniana and restricted control snails to consuming only as much as treatment snails consumed. Growth measured as shell diameter was significantly lower on the diet containing extract from induced, as opposed to non-induced, plants; change in snail mass was more variable and showed a similar, but non-significant, trend. Thus, snails may reduce feeding on induced plants to avoid suppression of fitness. The induced defenses also suppressed growth of co-occurring microbes that might attack the plant through herbivore-generated feeding scars. When two bacteria and three fungi isolated from C. caroliniana surfaces were cultured with the lipid extract from induced and non-induced C. caroliniana, both extracts inhibited the microbes, but the induced extract was more potent against three of the five potential pathogens. Thus, induced plant defenses can act against both direct consumers and microbes that might invade the plant indirectly through herbivore-generated wounds. PMID:20927537

Morrison, Wendy E; Hay, Mark E

2010-10-07

241

The role of Snail in prostate cancer.  

PubMed

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

2012-09-01

242

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

NASA Astrophysics Data System (ADS)

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

Tiwari, Farindra; Singh, D. K.

243

Linking calcification by exotic snails to stream inorganic carbon cycling.  

PubMed

Biotic calcification is rarely considered in freshwater C budgets, despite calculations suggesting that calcifying animals can alter inorganic C cycling. Most studies that have quantified biocalcification in aquatic ecosystems have not directly linked CO(2) fluxes from biocalcification with whole-ecosystem rates of inorganic C cycling. The freshwater snail, Melanoides tuberculata, has achieved a high abundance and 37.4 g biomass m(-2) after invading Kelly Warm Springs in Grand Teton National Park. This high biomass suggests that introduced populations of Melanoides may alter ecosystem processes. We measured Melanoides growth rates and biomass to calculate the production of biomass, shell mass, and CO(2). We compared Melanoides biomass and inorganic C production with ecosystem C pools and fluxes, as well as with published rates of CO(2) production by other calcifying organisms. Melanoides calcification in Kelly Warm Springs produced 12.1 mmol CO(2) m(-2) day(-1) during summer months. We measured high rates of gross primary productivity and respiration in Kelly Warm Springs (-378 and 533 mmol CO(2) m(-2) day(-1), respectively); CO(2) produced from biocalcification increased net CO(2) production in Kelly Warm Springs from 155 to 167 mmol CO(2) m(-2) day(-1). This rate of CO(2) production via biocalcification is within the published range of calcification by animals. But these CO(2) fluxes are small when compared to ecosystem C fluxes from stream metabolism. The influence of animals is relative to ecosystem processes, and should always be compared with ecosystem fluxes to quantify the importance of a specific animal in its environment. PMID:20058027

Hotchkiss, Erin R; Hall, Robert O

2010-01-08

244

Effects of endosulfan and ethanol on the reproduction of the snail Biomphalaria tenagophila: a multigeneration study.  

PubMed

Endosulfan (END) is an insecticide used in agriculture and as a wood preservative. Since END is practically insoluble in water, ethanol (ETOH) is often employed as a carrier solvent to spike it in the test medium in aquatic toxicity assays. In this study were investigated the effects of END and ETOH on the reproduction of the freshwater snail Biomphalaria tenagophila exposed over three successive generations. END (0, 0.001, 0.01, 0.1 mg L(-1)) was dissolved in the medium water using ETOH (up to 19.8 mg L(-1)) as carrier solvent. ETOH (19.8, 198, 1980 mg L(-1)) alone was tested as well. Adult snails (F(0)-generation) were exposed to END and ETOH for 8 weeks. The F(1)-generation continued to be exposed from embryo to reproductive maturity, while their descendants (F(2)) were exposed until day 10 after spawning. Effects on the fecundity (8-week production of eggs and egg-masses) of mature F(0) and F(1) snails were evaluated. Developmental toxicity was investigated in F(1) and F(2) embryos. END at the highest level tested (0.1 mg L(-1)) inhibited egg production by F(0) and F(1) snails. ETOH at levels 198 mg L(-1) also reduced fecundity of F(0) and F(1) an effect that was apparently aggravated by exposure over successive generations. END 0.1 mg L(-1) increased mortality and malformations and decreased hatching among F(1) embryos. ETOH drastically reduced the proportion of hatchings among F(2) embryos. The study-derived NOECs (no-observed-effect-concentrations) for END was 0.01 mg L(-1) (reduction in fecundity), and for ETOH were 19.8 mg L(-1) for reduction in fecundity and <19.8 mg L(-1) for developmental toxicity (hatching retardation). PMID:19138786

Oliveira-Filho, Eduardo Cyrino; Grisolia, Cesar Koppe; Paumgartten, Francisco Jose Roma

2009-01-12

245

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

PubMed Central

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

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

2010-01-01

246

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

PubMed

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

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

2009-12-06

247

Octopamine boosts snail locomotion: behavioural and cellular analysis  

Microsoft Academic Search

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

Jennifer C. Ormshaw; Christopher J. H. Elliott

2006-01-01

248

Freshwater Biological Traits Database.  

National Technical Information Service (NTIS)

The Freshwater Biological Traits Database currently contains traits data for 3,857 North American macroinvertebrate taxa and includes habitat, life history, mobility, morphology, and ecological trait data. Species traits are the characteristics that expla...

2012-01-01

249

Eosinophilic meningitis risk associated with raw Ampullarium canaliculatus snails consumption  

Microsoft Academic Search

In Taiwan, Angiostrongylus cantonensis infection has been reported in foreign laborers who had consumed raw Ampullarium canaliculatus snails. This study analyzed three foreign laborers who had contracted enzyme-linked immunosorbent assay-confirmed A cantonensis infection while working in Taiwan. All three workers had consumed either roasted snails or raw snails flavored with seasoning while drinking wine. This study investigated possible risk factors

Jiun-Jye Wang; Li-Yu Chung; Rong-Jyh Lin; June-Der Lee; Chaio-Wen Lin; Chuan-Min Yen

2011-01-01

250

Extinction or survival: partulid tree snails in American Samoa?  

Microsoft Academic Search

Four partulid tree snail species are known from American Samoa. In 1998, we surveyed the recently established National Park (units on three islands: Tutuila, Tau, Ofu) and neighboring areas for partulids. On Tutuila, Samoana abbreviata, previously considered probably extinct, was extremely rare (15 snails seen); Samoana conicawas more common (288 snails) but still rare; Eua zebrina was the most common

ROBERT H. COWIE; ROBERT P. COOK

2001-01-01

251

Larval trematodes: double infections in common mud-flat snail.  

PubMed

Larvae of the trematode Zoogonus lasius are involved in most double infections of Nassarius obsoleta. The two most common trematode parasites of this snail do not occur together in double infections. Double infections were found in 14 of 340 infected snails in a total sample of 5025 snails. PMID:5770621

Vernberg, W B; Vernberg, F J; Beckerdite, F W

1969-06-13

252

Mineral contents of tissues and body fluids and heavy metal contaminants of four predominant snail species in the Niger Delta  

Microsoft Academic Search

Mineral contents and heavy metal contaminants of four predominant snail species in the Niger Delta: African giant land snail (Archachatina marginata), African land snail (Achatina fulica), water snail (Pila ovata) and garden snail (Limicolaria aurora) were evaluated. Snail tissues and body fluids were harvested having cracked the tail-end of the shell. Triplicate samples of macerated snail tissues and body fluids

H. D. Mepba; C. U. Ogunka-Nnoka

253

The hemocyanin of the ramshorn snail, Marisa cornuarietis (Linné).  

PubMed

1. The hemocyanin of the freshwater snail, Marisa cornuarietis exists predominantly as a di-decamer with the approximate mol. wt of 8.5 x 10(6) and a sedimentation coefficient of 100 S. Sedimentation and scanning transmission electron microscopy experiments indicate that about 15-20% of the hemocyanin forms tri-decameric and possibly higher aggregates with mol. wts of 12.5 x 10(6) and 130 S. 2. The fully dissociated subunits in 8.0 M urea and 6.0 M GdmCl have mol. wts of 4.1 to 4.7 x 10(5) which is close to one-twentieth of the major di-decameric component of the native hemocyanin. 3. Subunit dissociation by the urea series and the Hofmeister salt series of reagents suggests hydrophobic stabilization of the decamers or half-molecules of the parent hemocyanin. As with the other molluscan hemocyanins the order of effectiveness of the ureas as dissociating agents shows increased efficacy with increasing hydrophobicity or chain-length of the urea substituents. 4. Denaturation of the hemocyanin subunits by the ureas and Hofmeister salt series, investigated by circular dichroism measurements, essentially follow the same trend in effectiveness as observed by changes in subunit dissociation followed by light-scattering mol. wt measurements. 5. The observed denaturation transitions are shifted to much higher ranges of reagent concentration than the concentrations required for the dissociation of the hemocyanin subunits. PMID:2085949

Herskovits, T T; Otero, R M; Hamilton, M G

1990-01-01

254

Aquatic Snails, Passive Hosts of Mycobacterium ulcerans  

PubMed Central

Accumulative indirect evidence of the epidemiology of Mycobacterium ulcerans infections causing chronic skin ulcers (i.e., Buruli ulcer disease) suggests that the development of this pathogen and its transmission to humans are related predominantly to aquatic environments. We report that snails could transitorily harbor M. ulcerans without offering favorable conditions for its growth and replication. A novel intermediate link in the transmission chain of M. ulcerans becomes likely with predator aquatic insects in addition to phytophage insects. Water bugs, such as Naucoris cimicoides, a potential vector of M. ulcerans, were shown to be infected specifically by this bacterium after feeding on snails experimentally exposed to M. ulcerans.

Marsollier, Laurent; Severin, Tchibozo; Aubry, Jacques; Merritt, Richard W.; Saint Andre, Jean-Paul; Legras, Pierre; Manceau, Anne-Lise; Chauty, Annick; Carbonnelle, Bernard; Cole, Stewart T.

2004-01-01

255

In situ cage experiments with Potamopyrgus antipodarum—A novel tool for real life exposure assessment in freshwater ecosystems  

Microsoft Academic Search

In situ experiments are an important tool within ecotoxicological research but there is a lack of suitable methodologies especially for freshwater invertebrate species. Within this study, a novel in situ methodology with Potamopyrgus antipodarum was developed. Snails were inserted into cages, made of Plexiglas measuring 7×9×7cm3 and fixed with stainless steel pins into the sediment at the relevant sampling sites.

Claudia Schmitt; Christian Vogt; Bram Van Ballaer; Rikke Brix; Annelies Suetens; Mechthild Schmitt-Jansen; Eric de Deckere

2010-01-01

256

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

USGS Publications Warehouse

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

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

1976-01-01

257

Freshwater Marsh. Habitat Pac.  

ERIC Educational Resources Information Center

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

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

258

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

2011-03-21

259

DNA strand breaks detected in embryos of the adult snails, Potamopyrgus antipodarum, and in neonates exposed to genotoxic chemicals.  

PubMed

We tested the freshwater mudsnail Potamopyrgus antipodarum, which is a species that has already been used for endocrine-disrupting compounds (EDCs) to determine whether early life stages of aquatic organisms are sensitive to genotoxic chemicals. For this purpose, we first developed the alkaline comet assay on adults, embryos, and neonates. The comet assay protocol was validated on both embryonic cells exposed in vitro to hydrogen peroxide and adult snails in the reproducing stage exposed to methyl methane sulfonate. During the latter experiment, DNA strand breaks were investigated on both embryonic cells and on adult gill cells. The second part of this study investigated the stability of DNA strand breaks in adult reproducing snails and neonates exposed to cadmium (Cd) and bisphenol A for 8 days. Hydrogen peroxide-induced DNA strand breaks in vitro in isolated embryonic cells. Exposure of adult reproducing snails to methyl methane sulfonate for 24h induced DNA strand breaks in embryos. Bisphenol A induced a significant increase in the DNA strand-break level in whole embryonic cells and whole neonate cells. Cd was genotoxic for both embryos and neonates during the exposure time and also after 7 days of depuration, suggesting that Cd could inhibit DNA repair enzymes. These preliminary results on this original model have encouraged us to consider the impact of genotoxic environmental contaminants on the F1 generation. PMID:22717255

Vincent-Hubert, Françoise; Revel, Messika; Garric, Jeanne

2012-05-22

260

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.

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

2006-01-01

261

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

2007-05-31

262

Molluscicidal activity of some marine substances against the snail Biomphalaria glabrata (Mollusca, Planorbidae).  

PubMed

Freshwater snails of the genus Biomphalaria play a major role as intermediate hosts of Schistosoma mansoni, the etiologic agent of schistosomiasis. While Biomphalaria spp. control by molluscicides is one of the main strategies to reduce the snail population in infected areas, there are few effective molluscicides commercially available. Natural products may be considered as potentially useful and safe molluscicides. We have evaluated the molluscicidal activity of 12 extracts from ten marine organisms on adult and embryonic stages of Biomphalaria glabrata. Only extracts of the red algae Liagora farinosa and of the sponge Amphimedon viridis presented molluscicidal activity. Lethal concentration (LC)(50) values obtained were 120 ?g/mL for L. farinosa CH(2)Cl(2) extract (apolar fraction) and 20 ?g/mL for A. viridis extract and halitoxin. The polar alga fraction and halitoxin had no effect on B. glabrata embryos. The algae apolar fraction was active on B. glabrata in all embryonic development stages, with LC(50) values for blastulae at 42 ?g/mL, gastrulae at 124 ?g/mL, trochophore at 180 ?g/mL, and veliger at 222 ?g/mL. This is the first report of extracts from marine organisms which presented molluscicidal activity. PMID:22205347

Miyasato, P A; Kawano, T; Freitas, J C; Berlinck, R G S; Nakano, E; Tallarico, L F

2011-12-29

263

Metabolism of ovorubin, the major egg lipoprotein from the apple snail.  

PubMed

The site of synthesis of molluscs lipoproteins is little known and was investigated for the egg lipoprotein perivitellin 1 (PV 1) or ovorubin in the freshwater snail Pomacea canaliculata. Tissues (albumen gland, gonad-digestive gland complex and muscle) of vitellogenic females were incubated in vitro at 25 degrees C for 12 h with 14C Leucine. After that, soluble proteins from tissue homogenates and medium samples were analysed for de novo protein synthesis by electrophoresis and HPLC, and radiolabelled proteins quantified by liquid scintillation. Gonad-digestive gland complex did not synthesise ovorubin, in spite its high protein synthesis levels. Three albumen gland radiolabelled proteins (35, 32 and 28 kDa) comigrated with the subunits of ovorubin and represented 1.3% of the total labelled protein of that tissue. Western blot analysis with polyclonal antibodies confirmed that these were ovorubin subunits. In vivo experiments where vitellogenic females were injected with 3H Leucine, revealed that ovorubin was not present in hemolymph. ELISA analysis confirmed ovorubin presence only in albumen gland and developing eggs with levels of 800 and 582 mg/g protein, which represent 30.3 and 28.4 mg ovorubin/g of tissue, respectively. Therefore, albumen gland is the single site of ovorubin synthesis as no extragland synthesis, circulation or accumulation could be detected in the apple snail. PMID:12619883

Dreon, Marcos S; Heras, Horacio; Pollero, Ricardo J

2003-01-01

264

The relevance of echocardiography heart measures for breeding against the risk of subaortic and pulmonic stenosis in Boxer dogs.  

PubMed

The aims of this study were to investigate the role and relative importance of auscultation and echocardiography traits as risk factors for the diagnosis of subaortic (SubAS) and pulmonic (PS) stenosis and to estimate the heritability (h(2)) of cardiac measurements taken through echocardiography for a random sample of Italian Boxer dogs. The data were cardiovascular examination results of 1,283 Italian Boxer dogs (686 females and 597 males) enrolled in the national screening program for heart defects arranged by the Italian Boxer Club. Examinations were performed during a 6-yr period by a group of 7 veterinary cardiologists following a standard protocol. Occurrence and severity of SubAS and PS were diagnosed, taking into account clinical and echocardiography findings such as the grade of cardiac murmur, direct ultrasound imaging of the anatomic obstructive lesions, and values of aortic or pulmonary blood flow velocities. A Bayesian logistic regression analysis was performed to identify clinical and echocardiography variables related to SubAS and PS diagnosis. Estimation of variance components for clinical and echocardiography traits was performed using a mixed linear animal model, Bayesian procedures, and the Gibbs sampler. Prevalence of SubAS (PS) was 8.4% (2.2) and 10.7% (6.4) for female and male dogs, respectively. Cardiac murmur, peak velocities, and annulus areas behaved as risk factors for SubAS and PS. The risk of a positive diagnosis for SubAS was 3 times greater for dogs with aortic annulus area <2.1 cm(2) relative to dogs with areas >2.37 cm(2), 84 times greater for dogs showing aortic peak velocities >2.19 m/s relative to dogs with peak velocities <1.97 m/s, and 41 times greater for dogs with moderate to severe murmur grades relative to dogs with absent murmur. Similar results were obtained for PS. The estimated h(2) for the occurrence of cardiac defects was 23.3% for SubAS and 8.6% for PS. Echocardiography and cardiac murmur grades exhibited moderate h(2) estimates and exploitable additive genetic variation. The estimated h(2) was 36, 24, and 20% for aortic annulus area, aortic peak velocity, and cardiac murmur score, respectively. For the area of the pulmonary annulus and peak pulmonary velocity, the estimated h(2) were smaller, ranging from 9.5 to 12.8%. These measures are candidate indicator traits that might be effectively used in dog breeding to reduce the prevalence and severity of cardiac defects. PMID:21908643

Menegazzo, L; Bussadori, C; Chiavegato, D; Quintavalla, C; Bonfatti, V; Guglielmini, C; Sturaro, E; Gallo, L; Carnier, P

2011-09-09

265

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

PubMed Central

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

Najarian, H. H.

1961-01-01

266

Effects of endocrine disruptors on prosobranch snails (Mollusca: Gastropoda) in the laboratory. Part II: Triphenyltin as a xeno-androgen.  

PubMed

In laboratory experiments the effects of suspected endocrine disrupting chemicals on freshwater and marine prosobranch species were analysed. In this second of three publications the responses of the freshwater ramshorn snail Marisa cornuarietis and of two marine prosobranchs (the dogwhelk Nucella lapillus and the netted whelk Hinia reticulata) to the xeno-androgenic model compound triphenyltin (TPT) are presented. Marisa and Nucella were exposed via water (nominal concentrations 5-500 ng TPT-Sn/L) and Hinia via sediments (nominal concentrations 50-500 micrograms TPT-Sn/kg dry wt.) for up to 4 months. Female ramshorn snails but not the two marine species developed imposex in a time and concentration dependent manner (EC10 4 months: 12.3 ng TPT-Sn/L) with a comparable intensity as described for tributyltin. TPT reduced furthermore the fecundity of Marisa at lower concentrations (EC10 4 months: 5.59 ng TPT-Sn/L) with a complete inhibition of spawning at nominal concentrations > or = 250 ng TPT-Sn/L (mean measured +/- SD: > or = 163 +/- 97.0 ng TPT-Sn/L). The extension of the pallial sex organs (penis with accessory structures and prostate gland) of male ramshorn snails and dogwhelks were reduced by up to 25% compared to the control but not in netted whelks. Histopathological analyses for M. cornuarietis and H. reticulata provide evidence for a marked impairment of spermatogenesis (both species) and oogenesis (only netted whelks). The test compound induced a highly significant and concentration independent increase in the incidence of hyperplasia on gills, osphradia and other organs in the mantle cavity of N. lapillus indicating a carcinogenic potential of TPT. The results show that prosobranchs are sensitive to endocrine disruption at environmentally relevant concentrations of TPT. Also, M. cornuarietis is a promising candidate for a future organismic invertebrate system to identify endocrine-mimetic test compounds. PMID:11214444

Schulte-Oehlmann, U; Tillmann, M; Markert, B; Oehlmann, J; Watermann, B; Scherf, S

2000-12-01

267

Effects of Larval Schistosomes on Biomphalaria Snails  

Microsoft Academic Search

\\u000a The aim of this chapter is to provide a clearer understanding of the complex relationship between Biomphalaria snails and larval schistosome parasites. This chapter describes the numerous changes in host physiology, biochemistry, and\\u000a behavior brought about by infection. Specifically, the effects of larval schistosomes on host mortality, growth, metabolism,\\u000a reproduction, organic and inorganic elements, and behavior are focused on. The

Judith Humphries

268

How Stress Alters Memory in 'Smart' Snails  

PubMed Central

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

Dalesman, Sarah; Lukowiak, Ken

2012-01-01

269

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

Microsoft Academic Search

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

Per Nyström; Jose R. Pérez

1998-01-01

270

Pink eggs and snails: field oviposition patterns of an invasive snail, Pomacea insularum , indicate a preference for an invasive macrophyte  

Microsoft Academic Search

Oviposition of non-calcareous or thinly shelled eggs represents an important life stage of many insects, amphibians, and several\\u000a gastropods. A recently identified invasive species of apple snail, Pomacea insularum, exhibits alarming invasive characteristics of high reproductive rates and generalist consumption patterns. This snail takes\\u000a the opposite approach to egg laying compared to most aquatic insects as adult snails crawl out

Romi L. BurksColin; Colin H. Kyle; Matthew K. Trawick

2010-01-01

271

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

PubMed

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

Salice, Christopher J; Kimberly, David A

2012-10-06

272

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

273

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

PubMed

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

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

2007-04-19

274

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

PubMed Central

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

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

2013-01-01

275

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

PubMed Central

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

Raghavan, Nithya; Tettelin, Herve; Miller, Andre; Hostetler, Jessica; Tallon, Luke; Knight, Matty

2009-01-01

276

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

277

The introduction of Melanoides tuberculata (Mollusca: Thiaridae) to the island of Saint Lucia (West Indies) and its role in the decline of Biomphalaria glabrata, the snail intermediate host of Schistosoma mansoni.  

PubMed

A malacological survey was carried out in May 1992 in the whole hydrographic system of Saint Lucia 11 years after the end of a biological control programme to eliminate Biomphalaria glabrata, the snail intermediate host of Schistosoma mansoni. A competitor snail, Melanoides tuberculata, was introduced to Saint Lucia in 1978 and field experiments in several habitats were conducted by Prentice between 1978 and 1986. At the present time M. tuberculata is the most common freshwater snail in Saint Lucia. The results of the survey, undertaken in sites where B. glabrata occurred in large populations in the past showed (i) the absence of the snail hosts from seven sites now extensively colonized by the competitor (ii) the presence of B. glabrata in low or very low densities in 17 sites together with the competitor and (iii) the presence of the intermediate hosts in large populations in only two sites where M. tuberculata was absent. These results confirm the positive results observed by Prentice. The presence of another planorbid snail, B. straminea, is reported for the first time in Saint Lucia. PMID:8103624

Pointier, J P

1993-06-01

278

The invasive snail Melanoides tuberculata in Argentina and Paraguay  

Microsoft Academic Search

This article reviews the spread and current distribution of the invasive snail Melanoides tuberculata in Argentina and Paraguay based on data from specimens deposited in museums, published reports and field collections. Field collections were made between April 1999 and May 2010. Snails were searched for using different collecting methods in a variety of habitats. Specimens were identified according to a

Juana G. Peso; Diego C. Pérez; Roberto E. Vogler

2011-01-01

279

Treatment Of Waste Water From Food Industry Using Snail Shell  

Microsoft Academic Search

Waste water from a food- factory was characterized and treated using snail shell. The aim was to find out the effectiveness of snail shell as a coagulant in waste water treatment. The result of the parameter studied before and after treatment, shows a change in color from dark brown before treatment to light brown after treatment, there was reduction in

E. O Jatto; I. O Asia; E. E Egbon; J. O Otutu; M. E Chukwuedo; C. J Ewansiha

2010-01-01

280

Long-term sensitization and environmental conditioning in terrestrial snails  

Microsoft Academic Search

The hypothesis that a long-term increase of behavioural responses in snails (over a period of days) might be due to environmental conditioning was examined. Training consisted of delivering electric shocks non-contingently with test stimuli twice per day for 5 days to freely moving snails on a ball floating in water. After training, a significant difference in amplitude of a withdrawal

P. Balaban; N. Bravarenko

1993-01-01

281

Sex and darts in slugs and snails (Mollusca: Gastropoda: Stylommatophora)  

Microsoft Academic Search

In the final stages of an elaborate courtship, many slugs and snails shoot calcareous 'love' darts into each other. While darts improve the reproductive success of the shooter, by promoting sperm survival in the recipient, it is unclear why some species have darts and others do not. In fact, dart use has barely been studied, except in the garden snail

Angus Davison; Christopher M. Wade; Peter B. Mordan; Satoshi Chiba

2005-01-01

282

Biological Control of Brown Garden Snails in California.  

National Technical Information Service (NTIS)

A snail of Mediterranean origin, Rumina has been in the USA since the 1820's and in California since the 1950's. Considered a nuisance and a pest by some homeowners, the decollate snail is nonetheless the only natural enemy that has proved effective again...

T. W. Fisher

1984-01-01

283

Snail silencing effectively suppresses tumour growth and invasiveness  

Microsoft Academic Search

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

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

2007-01-01

284

Inverse temperature acclimation of heart rate in hibernating land snails  

Microsoft Academic Search

The heart rates of quiescent land snailsHelix lucorum andH. aspersa were recorded by impedance pneumography over several days. When snails acclimated to warm, humid, long days were transferred in late autumn to cool, dry, short days, in order to permit hibernation inverse rotational acclimation occurred, so that heart rates at low temperatures were lowered. However, temperature dependence increased so that

Stuart E. R. Bailey; Maria Lazaridou-Dimitriadou

1991-01-01

285

Calcium cells from snails: Response to vitamin D metabolites  

Microsoft Academic Search

Calcium is one of the most important substances affecting the life of molluscs, and vitamin D was shown to be an essential nutrient for land snails. In an attempt to elucidate the role that vitamin D plays in calcium metabolism of land snails, we have developed a procedure for the isolation of specialized calcium cells from digestive gland of land

L. Kriajev; I. Otremski; S. Edelstein

1994-01-01

286

Neuron-independent Ca 2+ signaling in glial cells of snail’s brain  

Microsoft Academic Search

To directly monitor the glial activity in the CNS of the pond snail, Lymnaea stagnalis, we optically measured the electrical responses in the cerebral ganglion and median lip nerve to electrical stimulation of the distal end of the median lip nerve. Using a voltage-sensitive dye, RH155, we detected a composite depolarizing response in the cerebral ganglion, which consisted of a

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

2000-01-01

287

Calcareous Septa Formed in Snail Shells by Larvae of Snail-Killing Flies  

Microsoft Academic Search

Larvae of 13 species of Pherbellia and Colobaea that feed in exposed aquatic snails uitilize a product of the Malpighian tubules before they pupate to form a plate-like structure within the shell or to reinforce the anterior end of the puparium. The substance is partly calcium carbonate, and carbonic anhydrase may be involved in its production.

L. V. Knutson; C. O. Berg; L. J. Edwards; A. D. Bratt; B. A. Foote

1967-01-01

288

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

NASA Astrophysics Data System (ADS)

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

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

2005-05-01

289

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

Microsoft Academic Search

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

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

2000-01-01

290

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.

291

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

292

Acquisition of Ca 2+ and HCO 3 ? \\/CO 3 2? for shell formation in embryos of the common pond snail Lymnaea stagnalis  

Microsoft Academic Search

Embryos of the freshwater common pond snail Lymnaea stagnalis develop to hatch within 10 days under control conditions (22°C, Miami-Dade tap water) and this development is impaired by\\u000a removal of ambient calcium. In contrast, embryos did not exhibit dependence upon an ambient HCO3\\u000a ?\\/CO3\\u000a 2? source, developing and hatching in HCO3\\u000a ?\\/CO3\\u000a 2?-free water at rates comparable to controls. Post-metamorphic, shell-laying

Sue C. Ebanks; Michael J. O’Donnell; Martin Grosell

2010-01-01

293

Pan-European phylogeography of the aquatic snail Theodoxus fluviatilis (Gastropoda: Neritidae).  

PubMed

Investigating the geographical distribution of genetic lineages within species is critical to our understanding of how species evolve. As many species inhabit large and complex ranges, it is important that phylogeographical research take into account the entire range of widespread species to clarify how myriad extrinsic variables have affected their evolutionary history. Using phylogenetic, nested clade, and mismatch distribution analyses on a portion of the mitochondrial COI gene, I demonstrate that the wide-ranging freshwater snail Theodoxus fluviatilis possesses in parallel many of the phylogeographical patterns seen in less widespread freshwater species of Europe. Fragmentary forces play a major part in structuring the range of this species, with 12 of 14 geographically structured nested clades displaying a distribution consistent with fragmentation or restricted dispersal. Certain regions of southern Europe harbour the majority of genetic diversity (total haplotype diversity, H = 0.87), particularly Italy (H = 0.87) and areas surrounding the Black Sea (H = 0.81). Post-Pleistocene range expansion is pronounced, with the majority of northern European populations (95% of sample sites) having arisen from northern Italian individuals that initially colonized northern Germany. Additionally, two highly divergent haplotype lineages present in northern Germany imply that there were at least two postglacial recolonization routes. Estuaries may also provide a means of dispersal given that no genetic differentiation was found between estuarine populations and neighbouring freshwater populations. Taken together, these data reveal a species with a complex genetic history resulting from the fragmentary effects of European geology as well as continuous and discrete range expansion related to their aquatic biology. PMID:16313596

Bunje, Paul M E

2005-12-01

294

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

295

Lineage divergence of a freshwater snail clade associated with post-Tethys marine basin development.  

PubMed

The complex evolutionary history of the Eurasian gastropod lineage Theodoxus reflects the evolution of marine basins following the breakup of the Tethys Sea. Today, this clade inhabits the lakes, rivers, streams, and estuaries of Europe, southwestern Asia, and North Africa. Here we present the first phylogenetic hypothesis for this clade. Based upon extensive geographic and taxonomic sampling, portions of the mitochondrial genes for cytochrome c oxidase subunit I and 16S rRNA were sequenced and analysed using maximum likelihood and maximum parsimony methods. Results from bootstrap analyses, Bayesian analysis, and sensitivity analyses lend support to six deep phylogenetic subdivisions within Theodoxus. These major clades are geographically associated with the major post-Tethyan marine basins. Estimates of divergence times using a penalized likelihood approach indicate that divergence of these major lineages occurred during the Miocene, simultaneous with the breakup of the Mediterranean and Paratethys Seas. The resulting major subclades later diversified during the Pliocene, primarily within geographic regions associated with the eastern and western Mediterranean Sea, the Pannonian Basin, and the Black Sea, thus producing the extant species assemblages. Finally, these phylogenetic results imply that much of the current taxonomy is flawed, therefore we offer recommendations for revising the classification of Theodoxus species based on phylogenetic systematics. PMID:16949309

Bunje, Paul M E; Lindberg, David R

2006-07-18

296

Freshwater snails of East Caprivi and the lower Okavango River Basin in Namibia and Botswana  

Microsoft Academic Search

A systematic account is given of the aquatic gastropod fauna of the lower Okavango River in Namibia and Botswana, and of the East Caprivi area in Namibia, based on collections made mostly in 1983–86 from about 100 different sites. A total of 20 living species are reported, 9 of them for the first time from this area: Bellamya monardi, Lobogenes

D. S. Brown; B. A. Curtis; S. Bethune; C. C. Appleton

1992-01-01

297

Chromosomal studies on two Egyptian freshwater snails, Cleopatra and Bithynia (Mollusca-Prosobranchiata)  

Microsoft Academic Search

This study deals with the karyotype of Cleopatra bulimoides and a Bithynia spp., both belonging to class Gastropoda and subclass Prosobranchia but to two different families, namely Thiaridae and Bithyniidae.The observed diploid chromosome number for Cleopatra was 2n=28, and for Bithynia 2n= 32. The mitotic chromosomes of Cleopatra consisted of four metacentric pairs, eight submetacentric pairs and two telocentric pairs

Amany A. Tohamy; Shaimaa M. Mohamed

298

No effect of mate novelty on sexual motivation in the freshwater snail Biomphalaria glabrata  

Microsoft Academic Search

BACKGROUND: When mating effort (e.g. via ejaculates) is high, males are expected to strategically allocate their resources depending on the expected fitness gains from a given mating opportunity. One mechanism to achieve strategic mating is the Coolidge effect, where male sexual motivation declines across repeated encounters with a familiar partner, but resuscitates when encountering a novel female. Experimental tests of

Ines K Häderer; Johanna Werminghausen; Nico K Michiels; Nadine Timmermeyer; Nils Anthes

2009-01-01

299

Notes on East African land and freshwater snails, 12-15  

Microsoft Academic Search

The following notes mostly concern the description of new species from East Africa in connection with renewed work on a check-list of the non-marine Mollusca of that area which has been in preparation during the past 25 years. A fairly complete manuscript has been available for many years but additional material and further research continually render it in need of

B. Verdcourt

1982-01-01

300

Volatile foraging kairomones in the littoral zone: attraction of an herbivorous freshwater gastropod to algal odors.  

PubMed

Volatile organic compounds (VOCs) produced by algae and cyanobacteria are primarily responsible for odors in fresh waters. Among other functions, VOCs may serve as important infochemicals in biofilms of benthic primary producers. VOCs liberated by benthic, mat-forming cyanobacteria can be used as habitat-finding cues by insects, nematodes, and possibly other organisms. We developed a new gastropod behavioral assay that allows detection of food preference without offering food, thus allowing the distinction between taste, which requires direct contact with the food source, and the detection of odorous infochemicals, which work over distance. We demonstrated that VOCs released from disintegrated cells of a benthic, mat-forming, green alga (Ulothrix fimbriata) are food-finding cues ("foraging kairomones") that attract the herbivorous freshwater snail Radix ovata. A mixture of three C5 lipoxygenase compounds and 2(E),4(E)-heptadienal that mimic the major VOCs released by U. fimbriata attracted the snails, whereas neither the mixture of C5 compounds nor 2(E),4(E)-heptadienal were effective when given alone. This study suggests that VOCs can play a steering role as infochemicals in freshwater benthic habitats, as has been established for many organismic interactions in terrestrial ecosystems. PMID:16902829

Fink, Patrick; von Elert, Eric; Jüttner, Friedrich

2006-08-11

301

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

PubMed

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

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

2008-06-25

302

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

PubMed

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

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

1997-01-01

303

Characterization of the major egg glycolipoproteins from the perivitellin fluid of the apple snail Pomacea canaliculata.  

PubMed

Ovorubin and PV2 are the major lipoglycocarotenoproteins present in the perivitellus of the freshwater snail eggs of Pomacea canaliculata, a rapidly expanding rice field pest. We have previously characterized these two particles regarding their lipid and protein compositions, their synthesis and tissular distribution, and their contributions of energy and structural precursors for the developing embryo. In the present study, we have characterized the glycosidic moieties associated to these perivitellines. Both proteins were isolated from egg homogenates by ultracentrifugation, and high performance liquid chromatography (HPLC) using anionic exchange and size exclusion columns. Total carbohydrates accounted for 17.8% and 2.5% (w/w) of the apparent molecular mass of ovorubin and PV2, respectively. Analysis by size exclusion chromatography showed that the amount of O-linked oligosaccharides is higher than that of the N-linked species (59% and 67% w/w of total carbohydrates of ovorubin and PV2, respectively). Glycosylation patterns were determined by a set of biotinilated lectins onto blotted purified proteins. Lectin affinities confirmed the presence of aspargine-linked carbohydrates, probably of hybrid and high mannose types. Jacaline affinity suggested the presence of O-linked residues derived from the T-antigen. Total carbohydrate composition determined by gas liquid chromatography (GLC) showed that mannose was the major monosaccharide in both perivitellins followed by GlcNAc and Gal in ovorubin, and Gal and GlcNAc in PV2. Only one fatty acid (22:1 n-9) accounted for 46% and 56% of the fatty acids present in ovorubin and PV2, respectively. Carbohydrate role on these reserve proteins during embryogenesis of the apple snail is discussed. PMID:15112330

Dreon, Marcos S; Heras, Horacio; Pollero, Ricardo J

2004-07-01

304

Energy saving through trail following in a marine snail  

PubMed Central

Most snails and slugs locomote over a layer of mucus and although the resultant mucus trail is expensive to produce, we show that this expense can be reduced by trail following. When tracking over fresh conspecific trails, the marine intertidal snail Littorina littorea (L.) produced only approximately 27% of the mucus laid by marker snails. When tracking over weathered trails, snails adjusted their mucus production to recreate a convex trail profile of similar shape and thickness to the trail as originally laid. Maximum energy saving occurs when following recently laid trails which are little weathered. Many and diverse ecological roles for trail following have been proposed. Energy saving is the only role that applies across the Gastropoda and so may help to explain why trail following is such a well-established behaviour.

Davies, Mark S; Blackwell, Janine

2007-01-01

305

Population structure and coil dimorphism in a tropical land snail  

Microsoft Academic Search

Tree snails of the subgenus Amphidromus s. str. are unusual because of the chiral dimorphism that exists in many species, with clockwise (dextrally) and counter-clockwise (sinistrally) coiled individuals co-occurring in the same population. Given that mating in snails is normally impeded when the two partners have opposite coil, positive frequency-dependent selection should prevent such dimorphism from persisting. We test the

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

2005-01-01

306

Ecdysteroid metabolism in the terrestrial snail Cepaea nemoralis (L.)  

Microsoft Academic Search

Garden snails (Cepaea nemoralis) contain both ecdysone and ecdysterone. Attempts to determine whether they originate from their food or are endogenously synthesized did not allow a definite conclusion.The metabolism of ecdysone and 20-hydroxyecdysone in Cepaea nemoralis has been investigated by using tritiated hormone injections followed by HPLC analysis of labelled compounds. It was observed that snails convert ecdysone into 20-hy-hroxyecdysone

M. Garcia; J.-P. Girault; R. Lafont

1986-01-01

307

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

308

Snail Hepatopancreatic Lipase: A New Member of Invertebrates Lipases' Group  

Microsoft Academic Search

Higher animal's lipases are well characterized; however, much less is known about lipases from mollusks. A lipolytic activity\\u000a was located in the land snail (Eobania vermiculata) digestive glands (hepatopancreas), from which a snail digestive lipase (SnDL) was purified. Pure SnDL has a molecular mass\\u000a of 60 kDa; it does not present the interfacial activation phenomenon. It was found to be more

Sawsan Amara; Ahmed Fendri; Nadia Ben Salem; Youssef Gargouri; Nabil Miled

2010-01-01

309

Simultaneous multiple species testing: Acute toxicity of 13 chemicals to 12 diverse freshwater amphibian, fish, and invertebrate families  

Microsoft Academic Search

This test series developed methods for testing a compliment of aquatic organisms in a single test that satisfies the freshwater acute toxicity requirements for setting water quality criteria. Species tested included fathead minnowsPimephales promelas, rainbow troutSalmo gairdneri, bluegillLepomis macrochirus, channel catfishIctalurus punctatus, goldfishCarassius auratus, white suckerCatostomus commersoni, daphnidDaphnia magna, midgeTanytarsus dissimilis, crayfishOrconectes immunis, snailAplexa hypnorum, tadpoleXenopus laevis, and leechNephelopsis obscura.

Gary W. Holcombe; Gary L. Phipps; Abdul H. Sulaiman; Alex D. Hoffman

1987-01-01

310

Bisphenol A induces superfeminization in the ramshorn snail Marisa cornuarietis(Gastropoda: Prosobranchia) at environmentally relevant concentrations.  

PubMed

Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 microg/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 degrees C (EC10 998 ng/L) when compared with 20 degrees 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 degrees 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

2006-04-01

311

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

PubMed

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

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

2013-08-20

312

Pak1 Phosphorylation of Snail, a Master Regulator of Epithelial-to-Mesenchyme Transition, Modulates Snail's Subcellular Localization and Functions  

Microsoft Academic Search

The process of epithelial-mesenchymal transition plays a pivotal role in the conversion of early stage tumors into invasive malignancies, and has been shown to be regulated by the zinc finger phosphoprotein, Snail; however, no upstream signaling kinases have been shown to modulate Snail functions. Since the invasiveness of breast cancer cells is also influenced by p21-activated kinase 1 (Pak1) signaling,

Zhibo Yang; Suresh Rayala; Diep Nguyen; Ratna K. Vadlamudi; Shiuan Chen

2005-01-01

313

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

314

The Hypoxia-controlled FBXL14 Ubiquitin Ligase Targets SNAIL1 for Proteasome Degradation*  

PubMed Central

The transcription factor SNAIL1 is a master regulator of epithelial to mesenchymal transition. SNAIL1 is a very unstable protein, and its levels are regulated by the E3 ubiquitin ligase ?-TrCP1 that interacts with SNAIL1 upon its phosphorylation by GSK-3?. Here we show that SNAIL1 polyubiquitylation and degradation may occur in conditions precluding SNAIL1 phosphorylation by GSK-3?, suggesting that additional E3 ligases participate in the control of SNAIL1 protein stability. In particular, we demonstrate that the F-box E3 ubiquitin ligase FBXl14 interacts with SNAIL1 and promotes its ubiquitylation and proteasome degradation independently of phosphorylation by GSK-3?. In vivo, inhibition of FBXl14 using short hairpin RNA stabilizes both ectopically expressed and endogenous SNAIL1. Moreover, the expression of FBXl14 is potently down-regulated during hypoxia, a condition that increases the levels of SNAIL1 protein but not SNAIL1 mRNA. FBXL14 mRNA is decreased in tumors with a high expression of two proteins up-regulated in hypoxia, carbonic anhydrase 9 and TWIST1. In addition, Twist1 small interfering RNA prevents hypoxia-induced Fbxl14 down-regulation and SNAIL1 stabilization in NMuMG cells. Altogether, these results demonstrate the existence of an alternative mechanism controlling SNAIL1 protein levels relevant for the induction of SNAIL1 during hypoxia.

Vinas-Castells, Rosa; Beltran, Manuel; Valls, Gabriela; Gomez, Irene; Garcia, Jose Miguel; Montserrat-Sentis, Barbara; Baulida, Josep; Bonilla, Felix; de Herreros, Antonio Garcia; Diaz, Victor M.

2010-01-01

315

Functional Changes in the Snail Statocyst System Elicited by Microgravity  

PubMed Central

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

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

2011-01-01

316

Laboratory Survivorship of Aerially Exposed Pond Snails ('Physella integra') from Illinois. Long Term Resource Monitoring Program.  

National Technical Information Service (NTIS)

Many aquatic snails occupy ephemeral habitats that are occasionally subjected to severe environmental conditions. To investigate the physiological capacity of these animals to resist environmental changes, the authors aerially exposed aquatic pond snails ...

J. K. Tucker F. J. Janzen G. L. Paukstis

1997-01-01

317

Effects of Dietary Exposure to Forest Pesticides on the Brown Garden Snail 'Helix aspersa' Mueller.  

National Technical Information Service (NTIS)

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 c...

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

1994-01-01

318

the Puerto Rican freshwater crab, Epilobocera ... - Treesearch  

Treesearch

Phylogeography of an island endemic: the Puerto Rican freshwater crab, Epilobocera sinuatifrons ... not undertake amphidromous migration, and is restricted to purely freshwater habitats and adjacent riparian zones. ... Language: English.

319

Species-specific and transgenerational responses to increasing salinity in sympatric freshwater gastropods.  

PubMed

Freshwater salinization is a global concern partly attributable to anthropogenic salt contamination. The authors examined the effects of increased salinity (as NaCl, 250-4,000 µS/cm, specific conductance) on two sympatric freshwater gastropods (Helisoma trivolvis and Physa pomillia). Life stage sensitivities were determined by exposing naive eggs or naive juveniles (through adulthood and reproduction). Additionally, progeny eggs from the juvenile-adult exposures were maintained at their respective parental salinities to examine transgenerational effects. Naive H. trivolvis eggs experienced delayed development at specific conductance > 250 µS/cm; reduced survivorship and reproduction were also seen in juvenile H. trivolvis at 4,000 µS/cm. Survival and growth of P. pomilia were not affected by increased salinity following egg or juvenile exposures. Interestingly, the progeny of H. trivolvis exposed to higher salinity may have gained tolerance to increased salinity whereas P. pomilia progeny may have experienced negative transgenerational effects. The present study demonstrates that freshwater snail species vary in their tolerance to salinization and also highlights the importance of multigenerational studies, as stressor impacts may not be readily apparent from shorter term exposures. PMID:22865709

Suski, Jamie G; Salice, Christopher J; Patiño, Reynaldo

2012-08-31

320

Balloon valvuloplasty in 30 dogs with pulmonic stenosis: effect of valve morphology and annular size on initial and 1-year outcome.  

PubMed

Case records of 30 dogs in which valvular pulmonic stenosis (PS) was treated by balloon dilation were reviewed retrospectively. Physical examination, thoracic radiographs, 9-lead ECG, echocardiography, and Doppler studies were performed in all dogs. Two-dimensional and Doppler echocardiography were repeated after 24 h and 1 year after treatment. Dogs were divided into 2 groups based on their valvular anatomy on echocardiography and aortic:pulmonary ratio: 18 had type A PS with normal annulus diameter and aortic:pulmonary ratio < or = 1.2, and 12 had type B PS with pulmonary annulus hypoplasia and aortic:pulmonary ratio > 1.2. Most dogs in the type B group were brachycephalic and had no poststenotic dilatation on thoracic radiographs. Of the dogs with type A stenosis, 100% survived valvuloplasty with resolution of clinical signs. At 1-year follow-up, 94.4% were still alive and remained asymptomatic. Of those with type B stenosis, 66.6% had favorable outcome postvalvuloplasty. At 1-year follow-up, 66.6% of dogs were alive, and resolution of clinical signs was obtained in 50%. This study revealed the immediate and long-term efficacy of balloon valvuloplasty in dogs with PS. PMID:11817060

Bussadori, C; DeMadron, E; Santilli, R A; Borgarelli, M

321

Cercarial production of Fascioloides magna in the snail Galba truncatula (Gastropoda: Lymnaeidae)  

Microsoft Academic Search

Single-miracidium infections of Fascioloides magna in two populations of Galba truncatula were carried out under laboratory conditions to count free rediae and cercariae in snail cadavers just after death. Cercaria-shedding\\u000a snails were in low numbers, and their shell height at day 60 p.e. was significantly greater than that of numerous infected\\u000a snails that died without cercarial shedding. In snails that died

P. Vignoles; A. Novobilský; D. Rondelaud; V. Bellet; P. Treuil; B. Koudela; G. Dreyfuss

2006-01-01

322

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

323

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.

324

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

325

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

Microsoft Academic Search

Research on aquatic snails usually examines consumption of periphyton, but emergence of large, invasive aquatic snails that prefer macrophytes has necessitated a new understanding about snail her- bivory. Ample research exists detailing invasive potential of certain species of applesnails, such as Pomacea canaliculata, to successfully invade aquatic ecosystems. However, very few studies examine differ- ences in resource utilization between different

BRANDON B. BOLAND; M ARIANA MEERHOFF; CLAUDIA FOSALBA; NESTOR MAZZEO; MATTHEW A. BARNES; ROMI L. BURKS

2008-01-01

326

Genetic differentiation of aquatic snails (Gastropoda: Hydrobiidae) from artesian springs in and Australia  

Microsoft Academic Search

Electrophoretic surveys of 10 species of hydrobiid snails in two indigenous genera (Fonscochlea and Trochidrobia) living in arid-zone artesian ‘mound’ springs are reported. The study is based on 96 populations of hydrobiid snails living in 32 different springs representing 18 spring groups in the Lake Eyre Supergroup, northern South Australia. The species-level taxonomy of these snails, previously based on morphological

Winston F. Ponder; Peter Eggler; Donald J. Colgan

1995-01-01

327

The suitability of several aquatic snails as intermediate hosts for Angiostrongylus cantonensis  

Microsoft Academic Search

Sixteen species of aquatic snails of four families were tested by quantitative technique under standardized conditions for their suitability as intermediate hosts for Angiostrongylus cantonensis. These species were the planorbid snails Biomphalaria glabrata, Biomphalaria alexandrina, Planorbis planorbis, Planorbis intermixtus, Bulinus truncatus, Bulinus contortus, Bulinus africanus, Bulinus tropicus and Helisoma sp.; the lymnaeid snails Lymnaea natalensis, Lymnaea tomentosa, Lymnaea stagnalis, and

Fouad Yousif; Georg Lämmler

1975-01-01

328

Biochemical response of the brown garden snails, Helix aspersa to chlorfluazuron and flufenoxuron  

Microsoft Academic Search

The two insect growth inhibitors, chlorfluazuron (IKI7899) and flufenoxuron (Cascade) were evaluated for their toxic and biochemical action against the terrestrial snails Helix aspersa (Müller). Chlorfluazuron was found to be more toxic to the snails than flufenoxuron. The experimental snails were fed on lettuce discs treated with low concentration (1%) of each compound for a duration time of 1,2,3 and

M. A. Radwan; K. A. Osman; A. K. Salama

1993-01-01

329

Persistence and extinction of local populations of the garden snail Helix aspersa in unfavorable environments  

Microsoft Academic Search

In southern California, previously disturbed but currently uncultivated habitats are unfavorable environments for the introduced snail Helix aspersa. In these habitats, snails were often distributed in small, local populations only a few meters apart. Migration between neighboring populations was minimal because the snails have strong homing tendencies. Local micro-environmental differences produced differences in the demographic properties of 4 adjacent populations

D. C. Potts

1975-01-01

330

Periphytic food and predatory crayfish: relative roles in determining snail distribution  

Microsoft Academic Search

In the laboratory and field, we examined how periphyton (food of snails) and predatory crayfish influenced snail distribution in Trout Lake, a permanent, northern Wisconsin lake. Laboratory experiments (with no crayfish) tested the importance of periphyton biomass in determining snail preference among rocks, and among rock, sand, and macrophyte substrates. Among rocks with four different amounts of periphyton, periphyton biomass

L. M. Weber; D. M. Lodge

1990-01-01

331

Lats2 kinase potentiates Snail1 activity by promoting nuclear retention upon phosphorylation  

PubMed Central

Snail1 is a central regulator of epithelial cell adhesion and movement in epithelial-to-mesenchymal transitions (EMTs) during embryo development; a process reactivated during cancer metastasis. While induction of Snail1 transcription precedes EMT induction, post-translational regulation of Snail1 is also critical for determining Snail1's protein level, subcellular localization, and capacity to induce EMT. To identify novel post-translational regulators of Snail1, we developed a live cell, bioluminescence-based screen. From a human kinome RNAi screen, we have identified Lats2 kinase as a novel regulator of Snail1 protein level, subcellular localization, and thus, activity. We show that Lats2 interacts with Snail1 and directly phosphorylates Snail1 at residue T203. This occurs in the nucleus and serves to retain Snail1 in the nucleus thereby enhancing its stability. Lats2 was found to positively influence cellular EMT and tumour cell invasion, in a Snail1-dependent manner. Indeed during TGF?-induced EMT Lats2 is activated and Snail1 phosphorylated at T203. Analysis in mouse and zebrafish embryo development confirms that Lats2 acts as a positive modulator of Snail1 protein level and potentiates its in vivo EMT activity.

Zhang, Kun; Rodriguez-Aznar, Eva; Yabuta, Norikazu; Owen, Robert J; Mingot, Jose M; Nojima, Hiroshi; Nieto, M Angela; Longmore, Gregory D

2012-01-01

332

Characterization of transcriptomes from sexual and asexual lineages of a New Zealand snail (Potamopyrgus antipodarum).  

PubMed

Understanding the evolution and maintenance of sexual reproduction is one of the central challenges of evolutionary biology, yet we know very little about how sex influences molecular evolution. The New Zealand freshwater snail Potamopyrgus antipodarum is ideally suited to address this knowledge gap because obligately sexual individuals often coexist with multiple independently derived obligately asexual lineages. This unusual situation allows direct comparisons both between sexual and asexual P. antipodarum and across populations that differ in the relative frequency of sexual individuals. As such, P. antipodarum has received a great deal of attention as a model system for the maintenance of sex in nature and is also used as a model for environmental toxicology and biological invasions. Molecular genetic resources for P. antipodarum will thus be useful to investigators in a variety of biological fields. We used 454 sequencing of cDNA libraries to generate transcriptomes from two sexual and two asexual P. antipodarum lineages. A de novo assembly of 116.7 Mb of sequence reads produced 41 396 contigs, and sequence similarity-based Gene Ontology annotations were obtained for 3740 contigs. We detected 408 315 SNP loci and 7315 microsatellite loci, which together represent the first genome-scale resource available for P. antipodarum. Raw 454 read sequences, contig sequences, annotation data and polymorphism data are publicly available in a searchable online database and for download at http://www.biology.uiowa.edu/neiman/transcriptome.php. PMID:23280235

Wilton, Peter R; Sloan, Daniel B; Logsdon, John M; Doddapaneni, Harshavardhan; Neiman, Maurine

2012-12-27

333

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

PubMed

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

Yusa, Yoichi; Suzuki, Yoshito

2003-02-01

334

Population dynamics inferred from temporal variation at microsatellite loci in the selfing snail Bulinus truncatus.  

PubMed

We analyzed short-term forces acting on the genetics of subdivided populations based on a temporal survey of the microsatellite variability in the hermaphrodite freshwater snail Bulinus truncatus. This species inhabits temporary habitats, has a short generation time and exhibits variable rates of selfing. We studied the variability over three sampling dates in 12 Sahelian populations (1161 individuals). Classical genetic parameters (estimators of Ho, He, f, selfing rate and Fst) showed limited change over time whereas important temporal changes of allelic frequencies were detected for 10 of the ponds studied. These variations are not easily explained by selection, sampling drift and genetic drift alone and may be due to periodic migration. Indeed the habitats occupied by the populations studied are subject to large temporal fluctuations owing to annual cycles of drought and flood. In such ponds our results support a demographic model of population expansions and contractions under which available habitats, after the rainy season, are colonized by individuals originating from a smaller number of refuges (areas that never dry out in the deepest parts of the ponds). In contrast, selfing appeared to be an important force affecting the genetic structure in permanent ponds. PMID:9215901

Viard, F; Justy, F; Jarne, P

1997-07-01

335

Ontogenetic reaction norm for binary traits: the timing of phallus development in the snail Bulinus truncatus.  

PubMed

The ontogenetic trajectory of plastic binary traits may provide valuable insights into their evolutionary rate of change. In this paper, the timing of the plastic response of a temperature-dependent sexual polymorphism, aphally, is investigated in the freshwater snail Bulinus truncatus. Aphally is defined as the loss of the male copulatory organ in otherwise hermaphroditic animals. Individuals from two inbred lines were switched at various times during their early development between 25 and 30 degrees C, and their phally status ascertained, in order to evaluate the parameters characterising the ontogenetic reaction norm of aphally to temperature. A series of nested models including parameters for the onset, offset, and the intensity of the response to temperature were fitted to the data, allowing for a wide range of reaction norms. One genotype did not show any variation in aphally ratio with switching temperature, while a switch-point model (onset and offset corresponding to the same developmental point in time) best fitted the second genotype. The results suggest that the plasticity of aphally is expressed before eggs hatch. Their consequences on the evolution of aphally are discussed. More generally, the methodology proposed here can be used to analyse variation in ontogenetic parameters of discrete traits. PMID:11986869

Ostrowski, M-F; Jarne, P; Berticat, O; David, P

2002-05-01

336

Population Dynamics Inferred from Temporal Variation at Microsatellite Loci in the Selfing Snail Bulinus Truncatus  

PubMed Central

We analyzed short-term forces acting on the genetics of subdivided populations based on a temporal survey of the microsatellite variability in the hermaphrodite freshwater snail Bulinus truncatus. This species inhabits temporary habitats, has a short generation time and exhibits variable rates of selfing. We studied the variability over three sampling dates in 12 Sahelian populations (1161 individuals). Classical genetic parameters (estimators of H(o), H(e), f, selfing rate and Fst) showed limited change over time whereas important temporal changes of allelic frequencies were detected for 10 of the ponds studied. These variations are not easily explained by selection, sampling drift and genetic drift alone and may be due to periodic migration. Indeed the habitats occupied by the populations studied are subject to large temporal fluctuations owing to annual cycles of drought and flood. In such ponds our results support a demographic model of population expansions and contractions under which available habitats, after the rainy season, are colonized by individuals originating from a smaller number of refuges (areas that never dry out in the deepest parts of the ponds). In contrast, selfing appeared to be an important force affecting the genetic structure in permanent ponds.

Viard, F.; Justy, F.; Jarne, P.

1997-01-01

337

Interference with Fasciola hepatica snail finding by various aquatic organisms.  

PubMed

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

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

1977-06-01

338

Snail Cooperates with KrasG12D to Promote Pancreatic Fibrosis.  

PubMed

Patients with pancreatic cancer, which is characterized by an extensive collagen-rich fibrotic reaction, often present with metastases. A critical step in cancer metastasis is epithelial-to-mesenchymal transition (EMT), which can be orchestrated by the Snail family of transcription factors. To understand the role of Snail (SNAI1) in pancreatic cancer development, we generated transgenic mice expressing Snail in the pancreas. Because chronic pancreatitis can contribute to pancreatic cancer development, Snail-expressing mice were treated with cerulein to induce pancreatitis. Although significant tissue injury was observed, a minimal difference in pancreatitis was seen between control and Snail-expressing mice. However, because Kras mutation is necessary for tumor development in mouse models of pancreatic cancer, we generated mice expressing both mutant Kras(G12D) and Snail (Kras(+)/Snail(+)). Compared with control mice (Kras(+)/Snai(-)), Kras(+)/Snail(+) mice developed acinar ectasia and more advanced acinar-to-ductal metaplasia. The Kras(+)/Snail(+) mice exhibited increased fibrosis, increased phosphorylated Smad2, increased TGF-?2 expression, and activation of pancreatic stellate cells. To further understand the mechanism by which Snail promoted fibrosis, we established an in vitro model to examine the effect of Snail expression in pancreatic cancer cells on stellate cell collagen production. Snail expression in pancreatic cancer cells increased TGF-?2 levels, and conditioned media from Snail-expressing pancreatic cancer cells increased collagen production by stellate cells. Additionally, inhibiting TGF-? signaling in stellate cells attenuated the conditioned media-induced collagen production by stellate cells. Together, these results suggest that Snail contributes to pancreatic tumor development by promoting fibrotic reaction through increased TGF-? signaling. Implications: Expression of the EMT regulator Snail in the context of mutant Kras provides new insight into pancreatic cancer progression. Mol Cancer Res; 11(9); 1078-87. ©2013 AACR. PMID:23761168

Shields, Mario A; Ebine, Kazumi; Sahai, Vaibhav; Kumar, Krishan; Siddiqui, Kulsumjehan; Hwang, Rosa F; Grippo, Paul J; Munshi, Hidayatullah G

2013-06-12

339

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

340

Prioritized phenotypic responses to combined predators in a marine snail.  

PubMed

Although many species face numerous predators in nature, the combined impact of multiple predators on the inducible defenses of prey has rarely been studied. Prey may respond with an intermediate phenotype that balances the risk from several sources or may simply respond to the most dangerous predator. I examined the separate and combined effects of the presence of shell-breaking (crabs, Cancer productus) and shell-entry (seastars, Pisaster ochraceus) predators fed conspecific snails on the defensive shell morphology and antipredator behavior of a marine snail (Nucella lamellosa). When exposed to each feeding predator separately, snails responded with a combination of morphological defenses that reflect the attack mode of the predator and a generalized behavioral response. Snails responded to feeding crabs by increasing refuge use and producing a thick, rotund shell. Snails responded to feeding seastars with increased refuge use but produced elongate shells with high spires that allowed for greater retraction of the soft tissue. Seastar-induced phenotypes reduced susceptibility to seastars relative to crab-induced phenotypes, but crab-induced phenotypes did not significantly reduce susceptibility to crabs, indicating an asymmetrical functional trade-off. When feeding predators were combined, snails produced a morphological phenotype similar to that expressed in the presence of the predator that imposed the highest mortality at the population level, suggesting that predator-induced morphology was prioritized according to predation risk. These results suggest that prioritizing conflicting defenses according to predator danger may be a common strategy for prey responding to combined predators, particularly in conjunction with generalized behavioral responses that reduce overall risk in multiple-predator environments. PMID:19569380

Bourdeau, Paul E

2009-06-01

341

The effect of ecological parameters on the distribution of snail vectors of schistosomiasis.  

PubMed

The infestation of the water courses showed 32.5% for Biomphalaria alexandrina and 8.75% for Bulinus truncatus. Ecological parameters, showed non significant variations in the water courses harbouring snail vectors and those free from snails except for conductivity in the habitats harbouring B. truncatus. This variation was more highly significant (p<0.001). Of the examined sites, 11.25% were harbouring B. alexandrina and Lymnaea natalenesis living together and 5% of the sites were harbouring B. truncatus and Physa acuta snails. Snail vectors were distributed with different degrees with aquatic plants reflecting the degree of species preference plants for snails' life. PMID:12557938

Kader, A A

2001-04-01

342

Cercarial production of Fascioloides magna in the snail Galba truncatula (Gastropoda: Lymnaeidae).  

PubMed

Single-miracidium infections of Fascioloides magna in two populations of Galba truncatula were carried out under laboratory conditions to count free rediae and cercariae in snail cadavers just after death. Cercaria-shedding snails were in low numbers, and their shell height at day 60 p.e. was significantly greater than that of numerous infected snails that died without cercarial shedding. In snails that died between days 44 and 60 p.e. (at 20 degrees C), the numbers of second-generation rediae significantly increased with increasing shell heights of infected snails. First-generation rediae showed insignificant, quantitative variations, while scarce rediae of the third generation were only found in the highest snails. Cercariae were only produced by the second redial generation. In both groups of snails, free cercariae appeared from 6 mm of shell height, and their numbers increased in the upper classes up to 32.9 per snail. Metacercariae were only found from 9 mm of shell height and were in low numbers. The global cercarial production ranged from 163.5 to 210.0 in the highest classes of snail size from both groups and was limited, whereas the mean burdens of free rediae fluctuated from 39.5 to 43.9. The death of numerous infected snails without cercarial shedding might be explained by the presence of a very high number of second-generation rediae simultaneously growing within the body of these snails. PMID:16416118

Vignoles, P; Novobilský, A; Rondelaud, D; Bellet, V; Treuil, P; Koudela, B; Dreyfuss, G

2006-01-14

343

Metallothionein in the freshwater gastropod Melanopsis dufouri chronically exposed to cadmium: a methodological approach.  

PubMed

Previous studies have demonstrated that the use of differential pulse polarography (DPP) for metallothionein (MT) determination in marine gastropod tissues, particularly the digestive gland, requires taking into account the presence of heat-stable high molecular weight compounds that exhibit polarographic signal. In the present paper, similar compounds were identified in tissues from the freshwater snail Melanopsis dufouri which also interfere with MT determination by DPP and, due to their silver binding capacity, also interfere in the silver assay for MT quantification. Ultrafiltration seems to be effective in removing these high molecular weight compounds from heat-denatured homogenate supernatant allowing direct MT quantification by DPP. A fully validated procedure for metallothionein determination in M. dufouri is described. In spite of a considerable accumulation of cadmium in the visceral complex of M. dufouri following exposure to 100 microg CdL(-1) for 8 weeks (up to 37 microgg(-1)) only a small increase in MT concentration was found. PMID:20189648

Ureña, Rocío; João Bebianno, Maria; Del Ramo, Jose; Torreblanca, Amparo

2010-03-01

344

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

2011-08-30

345

Structuring of schistosomes and snails: Genetic insights and epidemiological consequences  

Microsoft Academic Search

Schistosoma mansoni is the digenean trematode responsible for chronic schistosomiasis in South America and the Caribbean and is one of several species of schistosomes that infect an estimated 200 million people across 74 countries worldwide. Lack of a vaccine, inconsistent sociopolitical will to maintain sanitation and control measures, and anthropogenic ecological disturbances that expand habitat range of the aquatic snail

Elizabeth A Thiele

2011-01-01

346

Sex and genetic variation in a helicid snail  

Microsoft Academic Search

Variation at enzyme loci has been investigated in the endemic Madeiran land snail Heterostoma paupercula (Gastropoda: Helicidae). There is a high degree of differentiation between populations. Part of the variation (about half of the total as measured by F statistics based on three polymorphic loci) is the result of divergence between populations of different islands. There are morphological differences between

L M Cook; L A Lace

1993-01-01

347

Respiratory behavior in the pond snail Lynmaea stagnalis  

Microsoft Academic Search

Previously (Syed et al. 1991) we described the ventilatory behavior of the pond snail Lymnaea stagnalis and identified motor neurons that innervate various muscles involved in this behavior. In the present study we describe an interneuronal network that controls ventilatory behavior in Lymnaea. An identified interneuron, termed the input 3 interneuron (Ip.3.I), was found to be involved in the opening

N. I. Syed; W. Winlow

1991-01-01

348

Character displacement and coexistence in mud snails (Hydrobiidae)  

Microsoft Academic Search

Populations of coexisting and of allopatrically occurring species of hydrobiid snails (Hydrobia ulvae, H. neglecta, H. ventrosa and Potamopyrgus jenkinsi) have been studied in 90 localities within three different areas. When H. ventrosa coexists with H. ulvae they show character displacement, i.e., the average body size of the former is smaller and that of the latter is larger. When these

Tom Fenchel

1975-01-01

349

Apple Snail: a Bio Cleaner of the Water Free Surface  

Microsoft Academic Search

Oil spills from tankers represent a threat for shorelines and marine life. Despite continuing research, there has been little change in the fundamental technology for dealing with oil spills. An experimental investigation of the feeding strategy of Apple snails from the water free surface, called surface film feeding, is being studied motivated by the need to develop new techniques to

Golnaz Bassiri

2005-01-01

350

Food Choice in the Common Snail (Helix Aspersa).  

ERIC Educational Resources Information Center

|The easily obtained common snail shows interesting dietary preferences which can be the source of several simple experiments. Specific student instructions are given for quantitative and comparative studies using cabbage, lettuce, carrot, rutabaga, and onion. Suggestions for laboratory setup and further work are included. (DH)|

Gill, John; Howell, Pauline

1985-01-01

351

Larval productivity of Fasciola gigantica in two lymnaeid snails.  

PubMed

Two groups of Galba truncatula and two groups of Lymnaea natalensis were experimentally infected with Fasciola gigantica to determine if snail species had an influence on the redial burden and cercarial shedding of this trematode when snails of both species were infected with the same isolate of miracidia. In the two groups used for the study of redial burden, the total number of free rediae was significantly higher at day 49 post-exposure in L. natalensis than in G. truncatula. In the groups used for cercarial shedding, the life-span of cercaria-shedding snails and those of infected snails which died without cercarial emission, and the duration of the prepatent period were significantly longer in L. natalensis than those noted in G. truncatula. However, the mean numbers of shed cercariae did not significantly differ and showed no differences in their daily distribution throughout the shedding period. These results demonstrate that G. truncatula might be the principal intermediate host of F. gigantica in Egypt, at least in the areas where this lymnaeid species lives. PMID:15469623

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

2004-09-01

352

Flying shells: historical dispersal of marine snails across Central America  

PubMed Central

The geological rise of the Central American Isthmus separated the Pacific and the Atlantic oceans about 3 Ma, creating a formidable barrier to dispersal for marine species. However, similar to Simpson's proposal that terrestrial species can ‘win sweepstakes routes’—whereby highly improbable dispersal events result in colonization across geographical barriers—marine species may also breach land barriers given enough time. To test this hypothesis, we asked whether intertidal marine snails have crossed Central America to successfully establish in new ocean basins. We used a mitochondrial DNA genetic comparison of sister snails (Cerithideopsis spp.) separated by the rise of the Isthmus. Genetic variation in these snails revealed evidence of at least two successful dispersal events between the Pacific and the Atlantic after the final closure of the Isthmus. A combination of ancestral area analyses and molecular dating techniques indicated that dispersal from the Pacific to the Atlantic occurred about 750 000 years ago and that dispersal in the opposite direction occurred about 72 000 years ago. The geographical distribution of haplotypes and published field evidence further suggest that migratory shorebirds transported the snails across Central America at the Isthmus of Tehuantepec in southern Mexico. Migratory birds could disperse other intertidal invertebrates this way, suggesting the Central American Isthmus may not be as impassable for marine species as previously assumed.

Miura, Osamu; Torchin, Mark E.; Bermingham, Eldredge; Jacobs, David K.; Hechinger, Ryan F.

2012-01-01

353

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.…

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

2007-01-01

354

Microgeographic evolution of snail shell shape and predator behavior  

Microsoft Academic Search

AbstractGenetic divergence in geographically isolated populations is a prerequisite for allopatric speciation, one of the most common modes of speciation. In ecologically equivalent populations existing within a small, environmentally homogeneous area, an important role for environmentally neutral divergence is often found or inferred. We studied a species complex of conspicuously shaped Opisthostoma land snails on scattered limestone outcrops within a

Menno Schilthuizen; Angelique van Til; Merijn Salverda; Thor-Seng Liew; S. Sheena James; Berjaya bin Elahan; Jaap J. Vermeulen

2006-01-01

355

Opiates stimulate food consumption in the land snail Helix aspersa.  

PubMed

Morphine stimulates food consumption in the land snail Helix aspersa. This stimulation of food consumption can be blocked by naloxone, the potent opiate antagonist. In addition, this opiate-induced food consumption exhibits tolerance by the sixth day of treatment. This study further highlights opioid mechanisms in relatively simple organisms and also suggests that these mechanisms are "ancient" signal systems. PMID:3123967

Ndubuka, C; Brown, D; Pratt, S; Braham, E; Leung, M K; Stefano, G B

1986-01-01

356

Quantifying Northern Hemisphere freshwater ice  

NASA Astrophysics Data System (ADS)

The areal extent and volume of peak freshwater (river and lake) ice are quantified across the Northern Hemisphere for the period 1957-2002. Quantification is conducted using a degree-day ice growth model and ice growth coefficients defined for 14 ice-specific hydroclimatic regions. The model is driven by ERA-40 gridded daily air temperature data, and the Global Lakes and Wetlands Database is employed to spatially define rivers and lakes. Results indicate that the total area covered by freshwater ice, at peak thickness, north of the January 0°C isotherm (excluding the Greenland ice sheet) is 1.7 × 106 km2 and the total freshwater ice volume is 1.6 × 103 km3. This area is approximately equal to that of the Greenland ice sheet and the volume to snow on land (Northern Hemisphere). Such values now permit a more complete quantification of the cryosphere (evaluations already having been completed for other components, such as snow, glaciers, and sea ice) and provide a reference data set for assessing future climate-related changes.

Brooks, Rheannon N.; Prowse, Terry D.; O'Connell, Ian J.

2013-03-01

357

Impairment of Context Memory by ?-Amyloid Peptide in Terrestrial Snail  

PubMed Central

We examined influence of the ?-amyloid peptide (?AP) (25–35) neurotoxic fragment on Helix lucorum food-aversion learning. Testing with aversively conditioned carrot showed that 2, 5 and 14 days after training the ?AP-injected group responded in a significantly larger number of cases and with a significantly smaller latency than the sham-injected control group. The results demonstrate that the AP partially impairs the learning process. In an attempt to specify what component of memory is impaired we compared responses in a context in which the snails were aversively trained, and in a neutral context. It was found that the sham-injected learned snails significantly less frequently took the aversively conditioned food in the context in which the snails were shocked, while the ?AP-injected snails remembered the aversive context 2 days after associative training, but were not able to distinguish two contexts 5, and 14 days after training. In a separate series of experiments a specific context was associated with electric shock, and changes in general responsiveness were tested in two contexts several days later. It was found that the ?AP-injected snails significantly increased withdrawal responses in all tested contexts, while the sham-injected control animals selectively increased responsiveness only in the context in which they were reinforced with electric shocks. These results demonstrate that the ?AP (25–35) interferes with the learning process, and may play a significant role in behavioral plasticity and memory by selectively impairing only one component of memory?– the context memory.

Korshunova, Tatiana A.; Bravarenko, Natalia I.; Balaban, Pavel M.

2008-01-01

358

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

2011-11-09

359

The human Lgl polarity gene, Hugl-2, induces MET and suppresses Snail tumorigenesis.  

PubMed

Lethal giant larvae proteins have key roles in regulating polarity in a variety of cell types and function as tumour suppressors. A transcriptional programme initiated by aberrant Snail expression transforms epithelial cells to potentially aggressive cancer cells. Although progress in defining the molecular determinants of this programme has been made, we have little knowledge as to how the Snail-induced phenotype can be suppressed. In our studies we identified the human lethal giant larvae homologue 2, Hugl-2, (Llgl2/Lgl2) polarity gene as downregulated by Snail. Snail binds E-boxes in the Hugl-2 promoter and represses Hugl-2 expression, whereas removal of the E-boxes releases Hugl-2 from Snail repression. We demonstrate that inducing Hugl-2 in cells with constitutive Snail expression reverses the phenotype including changes in morphology, motility, tumour growth and dissemination in vivo, and expression of epithelial markers. Hugl-2 expression reduced the nuclear localization of Snail and thus binding of Snail to its target promoters. Our results placing Hugl-2 within the Snail network as well as its ability to suppress Snail carcinogenesis identifies Hugl-2 as a target molecule driving cascades, which may have preventative and therapeutic promise to minimize cancer progression. PMID:22580609

Kashyap, A; Zimmerman, T; Ergül, N; Bosserhoff, A; Hartman, U; Alla, V; Bataille, F; Galle, P R; Strand, S; Strand, D

2012-05-14

360

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.

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

2011-01-01

361

Reversing the Resistance Phenotype of the Biomphalaria glabrata Snail Host Schistosoma mansoni Infection by Temperature Modulation  

PubMed Central

Biomphalaria glabrata snails that display either resistant or susceptible phenotypes to the parasitic trematode, Schistosoma mansoni provide an invaluable resource towards elucidating the molecular basis of the snail-host/schistosome relationship. Previously, we showed that induction of stress genes either after heat-shock or parasite infection was a major feature distinguishing juvenile susceptible snails from their resistant counterparts. In order to examine this apparent association between heat stress and snail susceptibility, we investigated the effect of temperature modulation in the resistant snail stock, BS-90. Here, we show that, incubated for up to 4 hrs at 32°C prior to infection, these resistant snails became susceptible to infection, i.e. shedding cercariae at 5 weeks post exposure (PE) while unstressed resistant snails, as expected, remained resistant. This suggests that susceptibility to infection by this resistant snail phenotype is temperature-sensitive (ts). Additionally, resistant snails treated with the Hsp 90 specific inhibitor, geldanamycin (GA) after heat stress, were no longer susceptible to infection, retaining their resistant phenotype. Consistently, susceptible snail phenotypes treated with 100 mM GA before parasite exposure also remained uninfected. These results provide direct evidence for the induction of stress genes (heat shock proteins; Hsp 70, Hsp 90 and the reverse transcriptase [RT] domain of the nimbus non-LTR retrotransposon) in B. glabrata susceptibility to S. mansoni infection and characterize the resistant BS-90 snails as a temperature-sensitive phenotype. This study of reversing snail susceptibility phenotypes to S. mansoni provides an opportunity to directly track molecular pathway(s) that underlie the B. glabrata snail's ability to either sustain or destroy the S. mansoni parasite.

Ittiprasert, Wannaporn; Knight, Matty

2012-01-01

362

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

363

Effect of three dormant oils on schistosomiasis and fascioliasis vector snails and its relation with some non-target snails.  

PubMed

Three oils were tested for their molluscicidal activity, Caple-2, Kemasol and Super-max. Super-max had the strongest toxic effect on B. alexandrina and other snail species. Its LC50 was 0.53 ppm, meanwhile LC50 of Kemasol 3.2 ppm and 4.21 ppm for Caple 2. The LC50 & LC90 of the oils were lower in Lymneae natalensis as compared to B. alexandrina. The LC50 & LC90 of the oils against non-target snails (Physa acuta, Helisoma duryi, Planorbis planorbis and Melanoides tuberculata) were higher as compared to B. alexandrina. Hatchability of snails' eggs exposed to Super-max (3.0 & 5.0 ppm) was stopped completely and l.0 ppm showed the lower percent of egg hatchability 22.7 %. Caple 2 and Kemasol did not affect eggs hatchability. Supermax had the strongest harmful effect on both miracidia and cercariae of S. mansoni. 100% mortality values were obtained for both larval stages after 8 & 9 minutes respectively when maintained at LC50. 100% mortality of miracidia occurred after 35 & 155 minutes when maintained at LC50 of Kemasol & Caple 2 respectively. The infection rate of B. alexandrina with S. mansoni miracidia was greatly reduced by the sublethal concentrations of the oils. The reduction of infection rate was higher in snails treated with Supermax (42.9%). A highly significant reduction of total cercarial production per snail was in the experimental groups as compared with controls. The prepatent period of treated snails was prolonged compared to control. Moreover, Total protein content and enzyme activities of snails treated with LC10 of oils showed a significant reduction as compared with control in haemolymyph. There was an increase of protein contents in the tissue. AlkP enzyme activity was slightly increased in haemolymph of experimental groups than controls and was significantly higher in the tissues as compared to control. ALT enzyme activity in haemolymph of experimental groups was higher than control, but lower in tissue. AST enzyme activity was higher in haemolymph and tissue of experimental groups than controls. The SDS-PAGE pattern of tissue soluble proteins extracted from treated B. alexandrina and controls showed different oils effects on the synthesis of protein within snails yielded a complex pattern of polypeptides ranging in molecular weight between 13.775 to 156.7 kDa. Many bands were present in treated snails. At least, one band was detected for snails treated with each of the oils and not in controls. The difference in the similarity indices between treatment and control; for Kemasol was 0.86 & 0.64, for Caple 2 was 0.61 & 0.55 and for Supermax was 0.64 & 0.86. LC25 of Supermax did not cause any mortality to Daphnia after 6 hr. But, LC50 & LC90 caused lower mortality after 6 hr. Kemasol caused 100% mortality after 4 hr at LC50 and 2 hr in LC90. Caple 2 caused 50% mortality of Daphnia after 5 hr at LC25 &100% mortality after 30 minutes in LC50 & LC90. PMID:17153697

Mostafa, Bayaumy B

2006-12-01

364

Variation of shell shape in the clonal snail Melanoides tuberculata and its consequences for the interpretation of fossil series.  

PubMed

Interpreting paleontological data is difficult because the genetic nature of observed morphological variation is generally unknown. Indeed, it is hardly possible to distinguish among several sources of morphological variation including phenotypic plasticity, sexual dimorphism, within-species genetic variation or differences among species. This can be addressed using fossil organisms with recent representatives. The freshwater snail Melanoides tuberculata ranks in this category. A fossil series of this and other species have been studied in the Turkana Basin (Kenya) and is presented as one of the best examples illustrating the punctuated pattern of evolution by the tenants of this theory. Melanoides tuberculata today occupies most of the tropics. We studied variation of shell shape in natural populations of this parthenogenetic snail using Raup's model of shell coiling. We considered different sources of variation on estimates of three relevant parameters of Raup's model: (1) variation in shell shape was detected among clones, and had both genetic and environmental bases; (2) sexual dimorphism, in those clones in which males occur, appeared as an additional source of shell variation; and (3) ecophenotypic variation was detected by comparing samples from different sites and years within two clones. We then tested the performance of discriminant function analyses, a classical tool in paleontological studies, using several datasets. Although the three sources of variation cited above contributed significantly to the observed morphological variance, they could not be detected without a priori knowledge of the biological entities studied. However, it was possible to distinguish between M. tuberculata and a related thiarid species using these analyses. Overall, this suggests that the tools classically used in paleontological studies are poorly efficient when distinguishing between important sources of within-species variation. Our study also gives some empirical bases to the doubts cast on the interpretation of the molluscan series of the Turkana Basin. PMID:10937226

Samadi, S; David, P; Jarne, P

2000-04-01

365

Conserving freshwater ecosystem values in Tasmania, Australia: identification and application of freshwater conservation management priority areas  

Microsoft Academic Search

The Conservation of Freshwater Ecosystem Values (CFEV) Project is a Tasmanian Government initiative that has developed a Comprehensive, Adequate and Representative (CAR) system as a strategic framework for the management and conservation of freshwater-dependent ecosystem values in Tasmania. At the core of the CFEV framework is a statewide audit of Tasmania's freshwater values for rivers, waterbodies, wetlands, saltmarshes, estuaries, karst

Danielle Hardie; Peter Davies

366

Biology of the snail-killing fly, Sepedon spangleri Beaver (Diptera: Sciomyzidae). II. Ability of the larvae to kill snails of medical importance in Thailand.  

PubMed

S. spangleri larvae preferred five species of non-operculate snails; Gyraulus convexiusculus Hutton, Segmentina hemisphaerula Benson, Hippeutis umbilicalis Benson, Indoplanorbis exustus Larambergue, and Trochobis trochoideus Benson. They occasionally consumed the operculate snails: Melanoides tuberculata Muller, Lithoglyphopsis aperta, Hubendickia siamensis Brandt, Lacunopis munensis Brandt, Tarebia granifera, Lamarch and Viviparus sp. but were innocuous to Bithynia laevis Lea. PMID:1025750

Sucharit, S; Chandavimol, Y; Sornmani, S

1976-12-01

367

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

368

Human Freshwater Demand for Economic Activity and Ecosystems in Taiwan  

Microsoft Academic Search

Freshwater is necessary to economic activity, and humans depend on goods and services generated by water-dependent ecosystems.\\u000a However, national freshwater management usually focuses on direct use of domestic freshwater. With an increasing scarcity\\u000a of freshwater, attention has turned to two indirect uses of freshwater by humans. The first indirect use is freshwater used\\u000a by foreign countries when producing products for

Jiun-Jiun Ferng

2007-01-01

369

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

PubMed

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

Arakelova, E S

370

Expression of Snail and Slug in renal cell carcinoma: E-cadherin repressor Snail is associated with cancer invasion and prognosis.  

PubMed

The Snail family transcription factors have been proposed as important mediators of epithelial-mesenchymal transition because of their role in down-regulation of E-cadherin and up-regulation of matrix metalloproteinases (MMPs). The present study was undertaken to investigate the expression of Snail, Slug and their associations with cancer invasion and prognosis in renal cell carcinomas (RCCs). Ninety-seven primary RCCs were analyzed for the protein expression of Snail, Slug, MMP2 and MMP9 by immunohistochemistry. Snail protein expression level was positively correlated with pathological tumor stage, histological grade and the presence of sarcomatoid carcinoma. On the contrary, Slug protein expression level was negatively correlated with pathological tumor stage, suggesting that Slug was down-regulated in advanced RCCs. Because Snail was positively associated with malignant potential of RCCs, involvement of Snail in the invasiveness of an RCC cell line 786-O was examined in the Matrigel invasion assay by down-regulating the gene expression with small interfering RNA (siRNA). Targeting the Snail, not Slug, expression in 786-O cells with siRNA caused down-regulation of the gene expression of Snail, vimentin, MMP2 and MMP9, but up-regulated the E-cadherin. Invasion of the cells through Matrigel in vitro was inhibited under this condition. Furthermore, expression levels of MMP2 and MMP9 were positively correlated with pathological tumor stage and the presence of sarcomatoid carcinoma. Statistical analysis indicated that elevated Snail, MMP2 and MMP9 protein expression are significantly worse predictors of disease-free and disease-specific survival of the patients with RCC. In conclusion, these data suggest that Snail has an important role in invasion and metastasis, and that silencing the gene may be a potential therapeutic target in RCCs. PMID:21808237

Mikami, Shuji; Katsube, Ken-Ichi; Oya, Mototsugu; Ishida, Masaru; Kosaka, Takeo; Mizuno, Ryuichi; Mukai, Makio; Okada, Yasunori

2011-08-01

371

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

372

Effect of X-ray on the snails of schistosomiasis in Egypt.  

PubMed

Biomphalaria alexandrina and Bulinus truncatus snails were exposed to sublethal doses 0.2, 3, 5, 10 and 20 rad of X-ray. The survival and reproductive rates of these snails were highly affected by these doses. The maximum survival periods of laboratory populations of Biomphalaria snails were less than those of field ones which means a high sensitivity of laboratory snails to X-ray. The reproductive capacity of irradiated Biomphalaria and Bulinus snails was highly suppressed and this will interrupt Schistosomiasis transmission. A deleterious effect of gametogenesis of irradiated Biomphalaria was histologically proved. After 3 weeks of snail irradiation with high dose (40 rad) the hermaphrodite gland became completely evacuated. PMID:8754647

Haroun, N H; Roushdy, M Z; Abdel Megeed, M I; Mostafa, B B

1996-08-01

373

Effects of Snail Density on Growth, Reproduction and Survival of Biomphalaria alexandrina Exposed to Schistosoma mansoni  

PubMed Central

The effects of snail density on Biomphalaria alexandrina parasitized with Schistosoma mansoni were investigated. Laboratory experiments were used to quantify the impact of high density on snail growth, fecundity, and survival. Density-dependent birth rates of snails were determined to inform mathematical models, which, until now, have assumed a linear relationship between density and fecundity. The experiments show that the rate of egg-laying followed a negative exponential distribution with increasing density and this was significantly affected by exposure to parasitic infection. High density also affected the weight of snails and survival to a greater degree than exposure to parasitic infection. Although snail growth rates were initially constrained by high density, they retained the potential for growth suggesting a reversible density-dependent mechanism. These experimental data can be used to parameterise models and confirm that snail populations are regulated by nonlinear density-dependent mechanisms.

Mangal, T. D.; Paterson, S.; Fenton, A.

2010-01-01

374

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

375

Inhibition of lactate dehydrogenase isoenzyme associated with anaerobic respiration in schistosomiasis intermediate host snails.  

PubMed

Lactate dehydrogenase isoenzyme (LD5) which is associated with anaerobic respiration was inhibited to a certain degree in Biomphalaria alexandrina snails, the intermediate host for Schistosoma mansoni. Urea and thiourea were used as inhibitors. The effect of LD5 inhibition on the mortality rate of infected Biomphalaria alexandrina snails and on the susceptibility of the snails to the trematode infection was also studied. PMID:1905584

Nabih, I; el Dardiri, Z; el-Ansary, A

1991-01-01

376

Calcium metabolism in two populations of the snail Helix aspersa on a high lead diet  

Microsoft Academic Search

Soft tissue concentrations of lead, calcium, and magnesium were measured in the garden snail,Helix aspersa, over a 64-day dosing regime. Snails were compared from an uncontaminated site and from a grossly polluted car park. In each case, 25 snails were given a diet with 500 µg\\/g Pb (as PbSO4), and 25 were removed to a Pb-free diet after two days

Alan Beeby; Larry Richmond

1988-01-01

377

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

Microsoft Academic Search

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

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

1994-01-01

378

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

Microsoft Academic Search

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

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

1994-01-01

379

The LIM Protein AJUBA Recruits Protein Arginine Methyltransferase 5 To Mediate SNAIL-Dependent Transcriptional Repression  

Microsoft Academic Search

The SNAIL transcription factor contains C-terminal tandem zinc finger motifs and an N-terminal SNAG repression domain. The members of the SNAIL family have recently emerged as major contributors to the processes of development and metastasis via the regulation of epithelial-mesenchymal transition events during embryonic development and tumor progression. However, the mechanisms by which SNAIL represses gene expression are largely undefined.

Zhaoyuan Hou; Hongzhuang Peng; Kasirajan Ayyanathan; Kai-Ping Yan; Ellen M. Langer; Gregory D. Longmore; Frank J. Rauscher

2008-01-01

380

Repression of PTEN phosphatase by Snail1 transcriptional factor during gamma radiation-induced apoptosis  

Microsoft Academic Search

The product of the Snail1 gene is a transcriptional repressor required for triggering the epithelial-to-mesenchymal transition. Furthermore, ectopic expression of Snail1 in epithelial cells promotes resistance to apoptosis. In this study, we demonstrate that this resistance to gamma radiation-induced apoptosis caused by Snail1 is associated with the inhibition of PTEN phosphatase. In MDCK cells, mRNA levels of the p53 target

Sandra Peiro; Nicolas Herranz; Patricia Villagrasa; Natalia Dave; Sentis B Montserrat; Stephen A. Murray; C. Franci; Thomas Gridley; Ismo Virtanen; de Herreros Garcia

2008-01-01

381

Exploring the Temporal Effects of Seasonal Water Availability on the Snail Kite of Florida  

Microsoft Academic Search

The Florida snail kite (Rostrhamus sociabilis) is an endangered raptor that occurs as an isolated population, currently of about 2,000 birds, in the wetlands of southern\\u000a and central Florida, USA. Its exclusive prey species, the apple snail (Pomacea paludosa) is strongly influenced by seasonal changes in water abundance. Droughts during the snail kite breeding season have a direct\\u000a negative effect

WOLF M. MOOIJ; JULIEN MARTIN; WILEY KITCHENS; DONALD DEANGELIS

2007-01-01

382

Reversing the Resistance Phenotype of the Biomphalaria glabrata Snail Host Schistosoma mansoni Infection by Temperature Modulation  

Microsoft Academic Search

Biomphalaria glabrata snails that display either resistant or susceptible phenotypes to the parasitic trematode, Schistosoma mansoni provide an invaluable resource towards elucidating the molecular basis of the snail-host\\/schistosome relationship. Previously, we showed that induction of stress genes either after heat-shock or parasite infection was a major feature distinguishing juvenile susceptible snails from their resistant counterparts. In order to examine this

Wannaporn Ittiprasert; Matty Knight

2012-01-01

383

Current advances on the study of snail-snail interactions, with special emphasis on competition process.  

PubMed

Field work research on population dynamic of snails from the regions of Belo Horizonte and Lagoa Santa give much information about interactions among two or more species of mollusks: Pomacea haustrum, Biomphalaria glabrata, B. tenagophila, B. straminea and Melanoides tuberculata. Data ranging from two years to several decades ago suggest that the Pampulha reservoir is like a cemetery of B. glabrata and B. straminea, species that coexist for more than 14 years in a small part of a stream, whereas only B. glabrata lives in all the streams of the basin. In the last ten to twenty years B. tenagophila has coexisted with P. haustrum and M. tuberculata in the Serra Verde ponds and in the Pampulha dam. However these species have not settled in any of the brooks, except temporarily. The data suggest that the kind of biotope and the habitat conditions are decisive factors for the permanence of each species in its preferencial biotope. B. glabrata, natural from streams and riverheads, quickly disappears from the reservoirs and ponds where it coexists with other species for a short time, independently of the competitive process. Competition needs to be better studied, since in Central America and Caribean islands this kind of study has favored the biological control of planorbid species. PMID:8531669

de Freitas, J R; dos Santos, M B

384

REVIEW MAGNESIUM TRANSPORT IN FRESHWATER TELEOSTS  

Microsoft Academic Search

The magnesium handling of freshwater teleost fish is discussed, with an emphasis on the role of branchial, intestinal and renal transport. In response to the eminent threat of constant diffusive losses of minerals such as magnesium, freshwater fish have developed efficient mechanisms for magnesium homeostasis. Magnesium losses are overcome by the uptake of magnesium from the food, making the intestine

MARCEL J. C. BIJVELDS; JOAN A. VAN DER VELDEN; ZVONIMIR I. KOLAR; GERT FLIK

1998-01-01

385

Freshwater Scarcity in the Nile River Basin.  

National Technical Information Service (NTIS)

According to a growing body of literature, scarcity of freshwater to meet the many needs of Third World countries is rapidly escalating. Furthermore, many of the remaining exploitable sources of freshwater are in river basins shared by two or more soverei...

K. F. Ubbelohde

2000-01-01

386

Extraction of Freshwater and Energy from Atmosphere  

Microsoft Academic Search

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

Alexander Bolonkin

2007-01-01

387

Intertidal snail-trematode communities on the southern Thailand before and after the South Asia tsunami.  

PubMed

Intertidal snail-trematode communities in southern Thailand were examined before and after the South Asia tsunami. Infection rates and species diversity of cercaria in the host snail Cerithidea in tidal zones did not change significantly from one year before to one month after the tsunami. However, the host snails C. quadrata, C. alata and C. obtusa disappeared from greatly damaged sites. It is important to follow up on the intertidal snail-trematode community recovery process after destruction of the intertidal ecosystem. PMID:17883003

Harada, Masakazu; Sri-aroon, Pusadee; Lohachit, Chantima; Fujimoto, Chigusa; Arif-Ul- Hasan; Itaki, Rodney; Suguri, Setsuo; Chusongsang, Yupa; Chusongsang, Phiraphol

2007-07-01

388

Analysis of Snail1 function and regulation by Twist1 in palatal fusion.  

PubMed

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

2013-02-19

389

The LIM protein AJUBA recruits protein arginine methyltransferase 5 to mediate SNAIL-dependent transcriptional repression.  

PubMed

The SNAIL transcription factor contains C-terminal tandem zinc finger motifs and an N-terminal SNAG repression domain. The members of the SNAIL family have recently emerged as major contributors to the processes of development and metastasis via the regulation of epithelial-mesenchymal transition events during embryonic development and tumor progression. However, the mechanisms by which SNAIL represses gene expression are largely undefined. Previously we demonstrated that the AJUBA family of LIM proteins function as corepressors for SNAIL and, as such, may serve as a platform for the assembly of chromatin-modifying factors. Here, we describe the identification of the protein arginine methyltransferase 5 (PRMT5) as an effector recruited to SNAIL through an interaction with AJUBA that functions to repress the SNAIL target gene, E-cadherin. PRMT5 binds to the non-LIM region of AJUBA and is translocated into the nucleus in a SNAIL- and AJUBA-dependent manner. The depletion of PRMT5 in p19 cells stimulates E-cadherin expression, and the SNAIL, AJUBA, and PRMT5 ternary complex can be found at the proximal promoter region of the E-cadherin gene, concomitant with increased arginine methylation of histones at the locus. Together, these data suggest that PRMT5 is an effector of SNAIL-dependent gene repression. PMID:18347060

Hou, Zhaoyuan; Peng, Hongzhuang; Ayyanathan, Kasirajan; Yan, Kai-Ping; Langer, Ellen M; Longmore, Gregory D; Rauscher, Frank J

2008-03-17

390

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.

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

2013-01-01

391

Phenotypic plasticity in two marine snails: constraints superseding life history.  

PubMed

In organisms encountering predictable environments, fixed development is expected, whereas in organisms that cannot predict their future environment, phenotypic plasticity would be optimal to increase local adaptation. To test this prediction we experimentally compared phenotypic plasticity in two rocky-shore snail species; Littorina saxatilis releasing miniature snails on the shore, and Littorina littorea releasing drifting larvae settling on various shores, expecting L. littorea to show more phenotypic plasticity than L. saxatilis. We compared magnitude and direction of vectors of phenotypic difference in juvenile shell traits after 3 months exposure to different stimuli simulating sheltered and crab-rich shores, or wave-exposed and crab-free shores. Both species showed similar direction and magnitude of vectors of phenotypic difference with minor differences only between ecotypes of the nondispersing species, indicating that plasticity is an evolving trait in L. saxatilis. The lack of a strong plastic response in L. littorea might be explained by limits rather than costs to plasticity. PMID:17040383

Hollander, J; Collyer, M L; Adams, D C; Johannesson, K

2006-11-01

392

Sexual selection maintains whole-body chiral dimorphism in snails  

PubMed Central

Although the vast majority of higher animals are fixed for one chiral morph or another, the cause for this directionality is known in only a few cases. In snails, for example, rare individuals of the opposite coil are unable to mate with individuals of normal coil, so directionality is maintained by frequency-dependent selection. The snail subgenus Amphidromus presents an unexplained exception, because dextral (D) and sinistral (S) individuals occur sympatrically in roughly equal proportions (so-called ‘antisymmetry’) in most species. Here we show that in Amphidromus there is sexual selection for dimorphism, rather than selection for monomorphism. We found that matings between D and S individuals occur more frequently than expected by chance. Anatomical investigations showed that the chirality of the spermatophore and the female reproductive tract probably allow a greater fecundity in such inter-chiral matings. Computer simulation confirms that under these circumstances, sustained dimorphism is the expected outcome.

SCHILTHUIZEN, M.; CRAZE, P. G.; CABANBAN, A. S.; DAVISON, A.; STONE, J.; GITTENBERGER, E.; SCOTT, B. J.

2007-01-01

393

Mercury residues in south Florida apple snails (Pomacea paludosa)  

SciTech Connect

Mercury concentrations in the sediments of south Florida wetlands have increased three fold in the last century. Because south Florida is home to many endemic and endangered species, it is important to understand the potential impacts of mercury in this ecosystem`s food web. Recent research by Malley et al. has shown mollusks to be sensitive indicators of methyl mercury which can reflect small differences in background methyl mercury concentrations. In this study, we attempted to determine if the apple snail (Pomacea paludosa) or its eggs are good indicators of bioavailable mercury. Then, using the apple snail as an indicator, we attempted to determine geographic differences in the concentrations of mercury in south Florida. 12 refs., 1 fig., 1 tab.

Eisemann, J.D.; Beyer, W.N.; Morton, A. [National Biological Services, Laurel, MD (United States); Bennetts, R.E. [Univ. of Florida, Gainesville, FL (United States)

1997-05-01

394

Controllable Snail-Paced Light in Biological Bacteriorhodopsin Thin Film  

Microsoft Academic Search

We observe that the group velocity of light is reduced to an extremely low value of 0.091mm\\/s in a biological thin film of bacteriorhodopsin at room temperature. By exploiting unique features of a flexible photoisomerization process for coherent population oscillation, the velocity is all-optically controlled over an enormous span, from snail-paced to normal light speed, with no need of modifying

Pengfei Wu

2005-01-01

395

Effect of Glyphosate on the Development of Pseudosuccinea columella Snails  

Microsoft Academic Search

.   Glyphosate (Roundup) is one of the most commonly used broad-spectrum herbicides with little to no hazard to animals, man,\\u000a or the environment. Due to its widespread use, there is continuous contamination of the environment in both soil and water\\u000a with this herbicide. There is a paucity of long-term exposure studies with sublethal concentrations of glyphosate on aquatic\\u000a snails. This

T. M. Tate; J. O. Spurlock; F. A. Christian

1997-01-01

396

Physical constraints on the foraging ecology of a predatory snail  

Microsoft Academic Search

We studied the effects of aerial exposure and high summer temperatures on the southern oyster drill (Stramonita haemastoma), feeding on the American oyster, Crassostrea virginica. In the laboratory, oyster drill feeding rates and growth were highest at 25 and 30°C, some mortality occurred at 35°C, all snails died at 40 and 45°C, and the 28-day LC 50 was 35.7°C. In

Kenneth M. Brown; William B. Stickle

2002-01-01

397

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

398

Lead reduces shell mass in juvenile garden snails ( Helix aspersa)  

Microsoft Academic Search

In an earlier paper examining inherited tolerance to Pb, the shell growth of laboratory-bred offspring of Helix aspersa from contaminated sites was compared with that of juveniles from na??ve populations on dosed and undosed diets. Eight-week-old snails were fed either 500 ?g g?1 Pb or a control food in competitive trials between two populations. In the first series of trials,

Alan Beeby; Larry Richmond; Florian Herpé

2002-01-01

399

Determinants of paternity in the garden snail Helix aspersa  

Microsoft Academic Search

Despite the likely importance of post-copulatory sexual selection in simultaneous hermaphrodites, the factors influencing sperm competition in these organisms are generally unknown. We have investigated the effects of dart-shooting, mating order, and several other predictors on the proportion of offspring fathered by penultimate (Pn-1) and ultimate (Pn) sperm donors in multiply mated garden snails, Helix aspersa. While paternity ratios were

David W. Rogers; Ronald Chase

2002-01-01

400

Functional Changes in the Snail Statocyst System Elicited by Microgravity  

Microsoft Academic Search

BackgroundThe mollusk statocyst is a mechanosensing organ detecting the animal's orientation with respect to gravity. This system has clear similarities to its vertebrate counterparts: a weight-lending mass, an epithelial layer containing small supporting cells and the large sensory hair cells, and an output eliciting compensatory body reflexes to perturbations.Methodology\\/Principal FindingsIn terrestrial gastropod snail we studied the impact of 16- (Foton

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

2011-01-01

401

Toxins from cone snails: properties, applications and biotechnological production  

Microsoft Academic Search

Cone snails are marine predators that use venoms to immobilize their prey. The venoms of these mollusks contain a cocktail\\u000a of peptides that mainly target different voltage- and ligand-gated ion channels. Typically, conopeptides consist of ten to\\u000a 30 amino acids but conopeptides with more than 60 amino acids have also been described. Due to their extraordinary pharmacological\\u000a properties, conopeptides gained

Stefan Becker; Heinrich Terlau

2008-01-01

402

Biological studies on the snail intermediate hosts of schistosomiasis with a special emphasis on using larval echinostomes as biocontrol agent against larval schistosomes and snails.  

PubMed

The present investigation deals with the infectivity of the two snail intermediate hosts of schistosomiasis, Biomphalaria alexandrina and Bulinus truncatus collected from nine drains in Sharkia Governorate, Egypt. The rate of infection among the snails was general low being 0% in many drains. Regarding B. alexandrina, the rate of infection ranged from 4-16%, and in B. truncatus ranged from 4-8%. Infection with larval echinostomes was dominant over larval schistosomes in the two snail vectors. The distribution of larval schistosomes was restricted to the hepatopancreas of the two snail vectors, while larval echinostomes were distributed in head, foot, kidney, haemocoelic cavity, hepatopancreas...etc. The predation of larval schistosomes by larval echinostomes and the severe histopathological effects induced by larval ecbinostomes strongly enhances using them as biocontrol agent. The physico-chemical parameters and pollution condition in the drains seem to have no effect on the process of snails infectivity. It is concluded that larval echinostomes can resist the polluting conditions in the drain. The two snail vectors exhibit very minimal or rare host response against larval echinostomes. Probably, the toxicants and pollutants in the drain may act as stressor that makes the snails much more susceptible to infection by larval trematodes. PMID:12512810

Rashed, A A

2002-12-01

403

Phosphorylated P68 RNA Helicase Activates Snail1 Transcription by Promoting HDAC1 Dissociation from the Snail1 Promoter  

PubMed Central

The nuclear p68 RNA helicase is a prototypical member of the DEAD box family of RNA helicases. P68 RNA helicase has been implicated in cell proliferation and early organ development and maturation. However, the functional role of p68 RNA helicase in these biological processes at the molecular level is not well understood. We previously reported that tyrosine phosphorylation of p68 RNA helicase mediates the effects of PDGF in induction of EMT by promoting ?-catenin nuclear translocation (Yang et.al. Cell 127:139-155 2006). Here we report that phosphorylation of p68 RNA helicase at Y593 up-regulates transcription of the Snail1 gene. The phosphorylated p68 activates transcription of the Snail1 gene by promoting HDAC1 dissociation from the Snail1 promoter. Our results showed that p68 interacted with the nuclear remodeling and deacetylation complex MBD3:Mi-2/NuRD. Thus, our data suggested that a DEAD box RNA unwindase can potentially regulate gene expression by functioning as a protein ‘displacer’ to modulate protein-protein interactions at the chromatin remodeling complex.

Carter, Christie L.; Lin, Chunru; Liu, Chia-yi; Yang, Liuqing; Liu, Zhi-Ren

2010-01-01

404

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

405

Migration and trail affinity of snails, Littoraria scabra, on mangrove trees of Nananu-i-ra, Fiji Islands  

Microsoft Academic Search

The distribution of mobile species such as grazing snails may be influenced by migration patterns, which often are excluded from ecological studies. To highlight this point, the migration patterns of Littoraria scabra on mangrove trees were investigated during incoming and outgoing tides at Nanaru-i-ra, Fiji Islands. Marked snails were used to track the position of snails, relative to the ground,

Andrea C. Alfaro

2007-01-01

406

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

407

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

408

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

409

Soil moisture and soil type influence the breeding behavior of the pest snail Cernuella virgata (da Costa)  

Microsoft Academic Search

The common white snail (Cernuella virgata) (da Costa) is an exotic pest of grain crops in southern Australia. In order to better control these snails and develop optimal management strategies, it is important to understand how their breeding behavior is influenced by soil moisture and soil type. Pairs of adult snails were placed into vials containing either a calcareous or

V. L. Carne-Cavagnaro; M. A. Keller; G. H. Baker

2006-01-01

410

Inhibition of egg hatching with apple wax solvent as a novel method for controlling golden apple snail ( Pomacea canaliculata)  

Microsoft Academic Search

Golden apple snail (Pomacea canaliculata) is an important pest of rice in Asia. Among chemicals screened for ability to inhibit hatching of snail eggs, morpholine which is a solvent of apple wax was very effective in suppressing hatching of snail eggs. At a concentration of 60%, or higher, morpholine completely suppressed egg hatching in the laboratory and outdoor conditions. Scanning

Der-Chung Wu; Jih-Zu Yu; Bing-Huei Chen; Chien-Yih Lin; Wen-Hsiung Ko

2005-01-01

411

Snail Grazing Effects on the Composition and Metabolism of Benthic Diatom Communities and Subsequent Effects on Fish Growth.  

National Technical Information Service (NTIS)

Eastern mud snails (Ilyanassa obsoleta) in densities of zero, six or twelve snails were placed in flow-through laboratory microcosms and incubated for five weeks. Other tanks were raked daily to a depth of 10 mm. Grazing by low densities of snails signifi...

M. S. Connor

1980-01-01

412

The Application of Electric Shock as a Novel Pest Control Method for Apple Snail, Pomacea canaliculata (Gastropoda: Ampullariidae)  

Microsoft Academic Search

The apple snail, Pomacea canaliculata, brought to Japan from Taiwan for human consumption in the 1980s, has come to be considered as deleterious for rice cultivation. The snail is unable to injure young rice plants while receiving electric shock because the snail retracts its entire body into its shell and shuts its aperture with its operculum. Electric shock should be

Yoshihito Yagyu; Satoshi Tsuji; Saburoh Satoh; Chobei Yamabe

2005-01-01

413

Nuclear Sex-Determining Genes Cause Large Sex-Ratio Variation in the Apple Snail Pomacea canaliculata  

PubMed Central

Evolutionary maintenance of genetic sex-ratio variation is enigmatic since genes for biased sex ratios are disadvantageous in finite populations (the “Verner effect”). However, such variation could be maintained if a small number of nuclear sex-determining genes were responsible, although this has not been fully demonstrated experimentally. Brood sex ratios of the freshwater snail Pomacea canaliculata are highly variable among parents, but population sex ratios are near unity. In this study, the effect of each parent on the brood sex ratio was investigated by exchanging partners among mating pairs. There were positive correlations between sex ratios of half-sib broods of the common mother (r = 0.42) or of the common father (r = 0.47). Moreover, the correlation between full-sib broods was very high (r = 0.92). Thus, both parents contributed equally to the sex-ratio variation, which indicates that nuclear genes are involved and their effects are additive. Since the half-sib correlations were much stronger than the parent–offspring regressions previously obtained, the variation was caused by zygotic sex-determining genes rather than by parental sex-ratio genes. The number of relevant genes appears to be small.

Yusa, Yoichi

2007-01-01

414

Nuclear sex-determining genes cause large sex-ratio variation in the apple snail Pomacea canaliculata.  

PubMed

Evolutionary maintenance of genetic sex-ratio variation is enigmatic since genes for biased sex ratios are disadvantageous in finite populations (the "Verner effect"). However, such variation could be maintained if a small number of nuclear sex-determining genes were responsible, although this has not been fully demonstrated experimentally. Brood sex ratios of the freshwater snail Pomacea canaliculata are highly variable among parents, but population sex ratios are near unity. In this study, the effect of each parent on the brood sex ratio was investigated by exchanging partners among mating pairs. There were positive correlations between sex ratios of half-sib broods of the common mother (r = 0.42) or of the common father (r = 0.47). Moreover, the correlation between full-sib broods was very high (r = 0.92). Thus, both parents contributed equally to the sex-ratio variation, which indicates that nuclear genes are involved and their effects are additive. Since the half-sib correlations were much stronger than the parent-offspring regressions previously obtained, the variation was caused by zygotic sex-determining genes rather than by parental sex-ratio genes. The number of relevant genes appears to be small. PMID:17057241

Yusa, Yoichi

2006-10-22

415

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

416

The Introduction of an Invasive Snail (Melanoides tuberculata) to Spring Ecosystems of the Bonneville Basin, Utah  

Microsoft Academic Search

Melanoides tuberculata is an invasive tropical prosobranch snail that was first introduced to the Bonneville Basin, Utah, sometime in the 1960's. During 2001 and 2002 we searched 276 sites\\/habitat types (limnocrenes, rheocrenes, and helocrenes) in 124 springs, nested in 14 valleys distributed throughout the Bonneville Basin and found this snail abundant in 17 of the 124 springs and occurring in

Russell B. Rader; Mark C. Belk; M. Jane Keleher

2003-01-01

417

Factors Affecting the Distribution and Abundance of Two Prosobranch Snails in a Thermal Spring  

Microsoft Academic Search

We studied the distribuiton and abundance of two prosobranch snails (Melanopsis praemorsa and Melanoides tuberculata) in a thermal spring (27°C) in southeast Morocco. Of the physicochemical and ecological parameters measured, food availability and water velocity appeared to be the main factors affecting the spatial distribution of these snails.

Hammou Laamrani; Khalid Khallayoune; Bernard Delay; Jean-Pierre Pointier

1997-01-01

418

The effects of endosulfan on the great ramshorn snail Planorbarius corneus (Gastropoda, Pulmonata): a histopathological study  

Microsoft Academic Search

In this study the great ramshorn snail (Planorbarius corneus), one of the most abundant gastropod of Turkish limnic systems, was investigated to determine the histopathological effects of endosulfan on the digestive gland, foot and mantle under laboratory conditions. Samples were collected from small artificial pools in Karaot at Gelendost-Isparta (Southwest of Turkey), where agricultural activities are widespread. The snails were

Birgül Otludil; Elif Ipek Cengiz; M. Zeki Yildirim; Özkan Ünver; Erhan Ünlü

2004-01-01

419

Detection of micronuclei in haemocytes of zebra mussel and great ramshorn snail exposed to pentachlorophenol  

Microsoft Academic Search

The frequency of micronuclei (MN) induced by pentachlorophenol (PCP) in haemocytes of zebra mussel, Dreissena polymorpha Pall. and great ramshorn snail, Planorbarius corneus L. was determined over a 14 days of exposure (sampling after 4, 7 and 14 days) under laboratory conditions. PCP doses for zebra mussel ranged from 10 to 150 ?g\\/l, and for ramshorn snail from 10 to

Mirjana Pavlica; Göran I. V Klobu?ar; Nataša Vetma; Radovan Erben; Dražena Papeš

2000-01-01

420

Measurement of some selected enzymatic activities in infected Biomphalaria alexandrina snails.  

PubMed

The activities of aspartate (AST) and alanine (ALT) aminotransferases and that of lactate dehydrogenase (LD) were measured in the homogenate of infected Biomphalaria alexandrina snails, the specific intermediate hosts for the parasite Schistosoma mansoni which is the cause of the disease schistosomiasis. The isoenzymatic pattern of LD was also studied in the infected snails tissue. PMID:2083418

Nabih, I; el Dardiri, Z; el-Ansary, A; Rizk, M

1990-01-01

421

Local adaptation of the trematode Fasciola hepatica to the snail Galba truncatula  

PubMed Central

Experimental infections of six riverbank populations of Galba truncatula with Fasciola hepatica were carried out to determine if the poor susceptibility of these populations to this digenean might be due to the scarcity or the absence of natural encounters between these snails and the parasite. The first three populations originated from banks frequented by cattle in the past (riverbank group) whereas the three others were living on islet banks without any known contact with local ruminants (islet group). After their exposure, all snails were placed in their natural habitats from the end of October up to their collection at the beginning of April. Compared to the riverbank group, snails, which died without cercarial shedding clearly predominated in the islet group, while the other infected snails were few in number. Most of these last snails released their cercariae during a single shedding wave. In islet snails dissected after their death, the redial and cercarial burdens were significantly lower than those noted in riverbank G. truncatula. Snails living on these islet banks are thus able to sustain larval development of F. hepatica. The modifications noted in the characteristics of snail infection suggest the existence of an incomplete adaptation between these G. truncatula and the parasite, probably due to the absence of natural contact between host and parasite.

Dreyfuss, G.; Vignoles, P.; Rondelaud, D.

2012-01-01

422

A repetitive DNA probe for the sensitive detection of Fasciola hepatica infected snails  

Microsoft Academic Search

Epizootiologic studies on F. hepatica frequently use microscopic techniques for the detection of infected snails, however, the poor efficiency, sensitivity, and specificity associated with these techniques limit their usefulness. A DNA-based test for the identification of snails infected with larval stages of F. hepatica would solve these problems and enable a level of detection accuracy previosly unavailable. We have cloned

R. M. Kaplan; J. B. Dame; G. R. Reddy; C. H. Courtney

1995-01-01

423

Local adaptation of the trematode Fasciola hepatica to the snail Galba truncatula.  

PubMed

Experimental infections of six riverbank populations of Galba truncatula with Fasciola hepatica were carried out to determine if the poor susceptibility of these populations to this digenean might be due to the scarcity or the absence of natural encounters between these snails and the parasite. The first three populations originated from banks frequented by cattle in the past (riverbank group) whereas the three others were living on islet banks without any known contact with local ruminants (islet group). After their exposure, all snails were placed in their natural habitats from the end of October up to their collection at the beginning of April. Compared to the riverbank group, snails, which died without cercarial shedding clearly predominated in the islet group, while the other infected snails were few in number. Most of these last snails released their cercariae during a single shedding wave. In islet snails dissected after their death, the redial and cercarial burdens were significantly lower than those noted in riverbank G. truncatula. Snails living on these islet banks are thus able to sustain larval development of F. hepatica. The modifications noted in the characteristics of snail infection suggest the existence of an incomplete adaptation between these G. truncatula and the parasite, probably due to the absence of natural contact between host and parasite. PMID:22910670

Dreyfuss, G; Vignoles, P; Rondelaud, D

2012-08-01

424

Tales of two snails: sexual selection and sexual conflict in Lymnaea stagnalis and Helix aspersa  

Microsoft Academic Search

Synopsis Sexual selection and sexual conflict have been shown to play key roles in the evolution of species with separate sexes. Experimental evidence is accumulating that this is also true for simultaneous hermaphrodites. For example, many species of land snails forcefully stab their mating partners with love darts. In the brown garden snail (Helix aspersa, now called Cantareus asperses), this

Joris M. Koene

2006-01-01

425

Snail ( Helix aspersa ) exposure history and possible adaptation to lead as reflected in shell composition  

Microsoft Academic Search

Lead sequestration in shell was examined for English and Welsh populations of the common garden snail (Helix aspersa) with different Pb exposure histories. Isotopic Pb ratios provided signatures for Pb source and a means of implying duration of population exposure from decades to millennia. Total Pb concentrations were used to quantify the intensity of exposure experienced by the populations. Snails

M. C. Newman; M. Mulvey; A. Beeby; R. W. Hurst; L. Richmond

1994-01-01

426

Growing snails used as sentinels to evaluate terrestrial environment contamination by trace elements  

Microsoft Academic Search

Young garden snails (Helix aspersa) reared in standard conditions (aged two months, mean weight 4.6±0.5 g) set as sentinels in cages laid on the soil for four weeks, give data for biomonitoring the environmental impact of chemicals on soil ecosystems in the field. The survival and the growth of the snails are influenced by the nature of the biotope and

A Gomot de Vaufleury; F Pihan

2000-01-01

427

Dissociation of sexual arousal and sexual proclivity in the garden snail, Helix aspersa.  

PubMed

Sexual arousal (intensity of courtship) and sexual proclivity (tendency to court) in Helix aspersa can be reliably measured using externally observable correlates. Snails with sexual proclivity are significantly more likely to turn toward an anesthetized conspecific after contacting it than are sexually unreceptive snails. Sexual arousal can be inferred from the stage of a snail's genital eversion, which appears only during courtship. The higher the stage of the eversion, the shorter the time required to complete introductory courtship behavior and the higher the rate of successful copulation, the fewer the number of breaks and pauses during courtship, and the longer the time a snail will spend in contact with an anesthetized conspecific. Sexual proclivity has no effect on feeding or locomotory behavior; however, sexual arousal inhibits feeding and increases locomotor activity. Snails that were allowed daily contact with conspecifics required less time to complete introductory courtship behavior relative to snails that were isolated from conspecifics for 1 week. This suggests that daily contact increases sexual arousal. A greater percentage of isolated snails exhibited courtship behavior than did snails which had experienced daily conspecific contact. This suggests that isolation increases sexual proclivity. These differences indicate that sexual arousal is not merely due to an increase in sexual proclivity. PMID:2241758

Adamo, S A; Chase, R

1990-09-01

428

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

429

Sex expression of an immobile coral-inhabiting snail, Quoyula monodonta  

Microsoft Academic Search

To test the hypotheses explaining the sex expression of the immobile snail Quoyula monodonta, which inhabits the surfaces of the branching coral, Pocillopora eydouxi, the size, sex, gonad development, penis length and the composition of neighboring individuals were investigated between November 1994 and August 1995 in southern Taiwan. Although the snails often aggregated and formed patches, more than 50% were

Keryea Soong; Ming-Hui Chen

2003-01-01

430

Enzootic Angiostrongylus cantonensis in Rats and Snails after an Outbreak of Human Eosinophilic Meningitis, Jamaica  

Microsoft Academic Search

After an outbreak in 2000 of eosinophilic meningitis in tourists to Jamaica, we looked for Angiostrongylus cantonensis in rats and snails on the island. Overall, 22% (24\\/109) of rats harbored adult worms, and 8% (4\\/48) of snails harbored A. cantonensis larvae. This report is the first of enzootic A. cantonensis infec- tion in Jamaica, providing evidence that this parasite is

John F. Lindo; Cecilia Waugh; John Hall; Colette Cunningham-Myrie; Deanna Ashley; Mark L. Eberhard; James J. Sullivan; Henry S. Bishop; David G. Robinson; Timothy Holtz; Ralph D. Robinson

2002-01-01

431

Genetic Diversity and Molecular Markers in Introduced and Thai Native Apple Snails (Pomacea and Pila)  

Microsoft Academic Search

The genetic diversity and species-diagnostic markers in the introduced apple snail, Pomacea canaliculata and in the native Thai apple snails; Pila ampullacea, P. angelica, P. pesmei, and P. polita, were investigated by restriction analysis of COI and are reported for the first time. Twenty- one composite haplotypes showing non-overlapping distributions among species were found. Genetic heterogeneity analysis indicated significant differences

Bungorn Thaewnon-ngiw; Sirawut Klinbunga; Nitsri Sangduen; Nitaya Lauhachinda; Piamsak Menasveta

2004-01-01

432

Herbivory on aquatic vascular plants by the introduced golden apple snail ( Pomacea canaliculata ) in Lao PDR  

Microsoft Academic Search

The effect of naturally found densities of the exotic and herbivorous golden apple snail (Pomacea canaliculata) on three dominant aquatic plants – duckweed (Lemna minor), water hyacinth (Eichhornia crassipes) and morning glory (Ipomoea aquatica) – was assessed in a wetland survey and quantified in a field experiment in Laos in southeast Asia. Snail grazing reduced plant biomass, but plant species

Nils O. L. Carlsson; Jean O. Lacoursière

2005-01-01

433

Occurrence of a blood group Alike substance in eggs of the prosobranch snail Pomacea canaliculata  

Microsoft Academic Search

Summary In the eggs of the prosobranch snailsPomacea canaliculata andPomacea insularum a blood group A-like substance has been detected by anti-A from the snailsHelix pomatia, Helix aspersa andCepaea nemoralis.

G. Uhlenbruck; G. Steinhausen; D. F. Cheesman; B. Helm

1976-01-01

434

The role of spatial processes and environmental determinants in microgeographic shell variation of the freshwater snail Chilina dombeyana (Bruguière, 1789).  

PubMed

Wildlife data often show spatial organization, demonstrating positive correlations either as a result of processes occurring over the landscape or due to the influence of spatially structured environmental variables. It is, thus, essential to consider non-random spatial structure when evaluating the underlying causes of biological variation. In this study, we analyzed the population structure of Chilina dombeyana shell morphology of 14 populations that are close geographically and belong to the same hydrographic basin. We utilized a variation partitioning approach to evaluate the importance of spatial processes, such as migration, acting over the landscape, and environmental characteristics, including habitat and hydrologic characteristics, and the occurrence of aquatic predators in promoting between population variation. Our results demonstrate spatially structured variation in C. dombeyana shell morphology, with populations living near each other having more similar shell sizes than populations living farther apart. The shell size variation partition indicated that both spatially structured environmental factors and genetic relationships resulting from migration or shared common ancestry may explain this pattern. Shell shape variation, in contrast, was found to be essentially under the influence of non-spatially structured environmental factors, with habitat and water characteristics accounting for about half of the total variation among populations. The large proportion of the variation in shell size that is spatially structured demonstrates that spatial structure on morphological traits might be strong and highlights the need to consider such phenomenon in intraspecific studies of phenotypic evolution. PMID:22328071

Bertin, Angéline; Ruíz, Victor H; Figueroa, Ricardo; Gouin, Nicolas

2012-02-12

435

The effect of organotin compounds on gender specific androstenedione metabolism in the freshwater ramshorn snail Marisa cornuarietis.  

PubMed

In a recent study, we demonstrated that androstenedione was mainly converted to testosterone (T) and 5alpha-dihydrotestosterone (DHT) by digestive gland/gonad complex microsomal fractions isolated from male Marisa cornuarietis, whereas it was primarily metabolized to 5alpha-dihydroandrostenedione (DHA) by females. In the present work, the sexual dimorphic metabolism of androstenedione was further investigated, and attributed to a higher 17beta-hydroxysteroid dehydrogenase activity in males than in females. Thereafter, the hypothesis was tested that the metabolism of androstenedione might be affected by exposure to tributyltin (TBT) and triphenyltin (TPT), which are known to induce the development of imposex in several gastropod species. The in vitro metabolism of androstenedione, particularly the formation of DHA and DHT, was inhibited by both compounds. However, in vivo experiments showed no significant alteration in the metabolism of androstenedione in males, but a marginal (TBT) and a significant (TPT) inhibition of the formation of DHA in females exposed for 150 days to concentrations that had significantly induced the development of imposex. The ratio DHT+T/DHA, a possible indicator of metabolic androgenization, tended to increase (0.43 versus 0.35, p=0.06) in TPT exposed females. However, this ratio never reached values comparable to those found in males (11+/-1). PMID:16621518

Janer, G; Bachmann, J; Oehlmann, J; Schulte-Oehlmann, U; Porte, C

2006-04-18

436

The effect of organotin compounds on gender specific androstenedione metabolism in the freshwater ramshorn snail Marisa cornuarietis  

Microsoft Academic Search

In a recent study, we demonstrated that androstenedione was mainly converted to testosterone (T) and 5?-dihydrotestosterone (DHT) by digestive gland\\/gonad complex microsomal fractions isolated from male Marisa cornuarietis, whereas it was primarily metabolized to 5?-dihydroandrostenedione (DHA) by females. In the present work, the sexual dimorphic metabolism of androstenedione was further investigated, and attributed to a higher 17?-hydroxysteroid dehydrogenase activity in

G. Janer; J. Bachmann; J. Oehlmann; U. Schulte-Oehlmann; C. Porte

2006-01-01

437

Natural range expansion and human-assisted introduction leave different genetic signatures in a hermaphroditic freshwater snail  

Microsoft Academic Search

Colonization events like range expansion or biological invasions can be associated with population bottlenecks. Small population\\u000a size may lead to loss of genetic diversity due to random genetic drift, to loss of heterozygosity due to increased inbreeding\\u000a and should leave a signature on the genetic polymorphism and genetic structure of populations. The mating system might additionally\\u000a influence the outcome of

Kirstin C. Kopp; Kirsten Wolff; Jukka Jokela

438

The role of spatial processes and environmental determinants in microgeographic shell variation of the freshwater snail Chilina dombeyana (Bruguière, 1789)  

NASA Astrophysics Data System (ADS)

Wildlife data often show spatial organization, demonstrating positive correlations either as a result of processes occurring over the landscape or due to the influence of spatially structured environmental variables. It is, thus, essential to consider non-random spatial structure when evaluating the underlying causes of biological variation. In this study, we analyzed the population structure of Chilina dombeyana shell morphology of 14 populations that are close geographically and belong to the same hydrographic basin. We utilized a variation partitioning approach to evaluate the importance of spatial processes, such as migration, acting over the landscape, and environmental characteristics, including habitat and hydrologic characteristics, and the occurrence of aquatic predators in promoting between population variation. Our results demonstrate spatially structured variation in C. dombeyana shell morphology, with populations living near each other having more similar shell sizes than populations living farther apart. The shell size variation partition indicated that both spatially structured environmental factors and genetic relationships resulting from migration or shared common ancestry may explain this pattern. Shell shape variation, in contrast, was found to be essentially under the influence of non-spatially structured environmental factors, with habitat and water characteristics accounting for about half of the total variation among populations. The large proportion of the variation in shell size that is spatially structured demonstrates that spatial structure on morphological traits might be strong and highlights the need to consider such phenomenon in intraspecific studies of phenotypic evolution.

Bertin, Angéline; Ruíz, Victor H.; Figueroa, Ricardo; Gouin, Nicolas

2012-03-01

439

The effects of myrrh (Commiphora molmol) on the infected snails of Schistosoma sp. and their egg masses: effect on shedding of cercariae and on snail fecundity.  

PubMed

Myrrh has molluscicidal effect on infected Bulinus truncatus and Biomphalaria alexandrina snails at low concentrations (10 & 20 ppm respectively) after 24 hours exposure. The number of dead-snails increased with prolongation of exposure time. All Schistosoma free cercariae were killed by 2.5 ppm within 15 minutes. One day-old egg masses were more susceptible to the ovicidal effect of Myrrh than the five-day old ones. Both types of eggs were more resistant to the effect of Myrrh than the adult snails, embryogenesis began to stop at 20 ppm and eggs were all killed at 60 & 80 ppm. Shedding of cercariae of Schistosoma mansoni from infected B. alexandrina stopped at 1 ppm and was suppressed at 0.8 ppm. Snail fecundity decreased at 1 ppm. PMID:14964669

Massoud, Ahmed M A; Habib, Faiza S M

2003-08-01

440

[Causation of Oncomelania snail recurrence in water-net areas of Jiaxing City].  

PubMed

From 2004 to 2012, fourteen Oncomelania snail remaining spots with an area of 31.954 hm2 were found in the historical snail areas of Xiuzhou District, Jiaxing City. The recurrence time of snails was 5-39 years. These spots were mainly distributed in the complex breeding environments, such as paddy fields (37.15%), nursery stock fields (36.93%), mulberry fields (16.09%), and ditches (6.82%). A total of 8 370 snails were dissected and no infected ones were found. It suggests that the nursery stock fields should be included in the key points for snail surveillance in water-net areas where schistosomiasis transmission has been interrupted. PMID:23593854

Xu, Hui-Qing; Zhu, Pei-Hua; Mo, Gen-Qiang

2012-12-01