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1

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

Microsoft Academic Search

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

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

2

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

PubMed

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

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

2012-05-01

3

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

PubMed

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

Omran, Nahla Elsayed; Salama, Wesam Mohamed

2013-11-01

4

Spotlight on the in vitro effect of artemisinin-naphthoquine phosphate on Schistosoma mansoni and its snail host Biomphalaria alexandrina.  

PubMed

Malaria and schistosomiasis are the two most important parasitic diseases in the tropics and sub-tropics with geographic overlap. Efforts have been made for developing new schistosomicidal drugs, or testing existing drugs originally used for non-related diseases. The antimalarial artemisinin-naphthoquine phosphate combination (CO-ArNp) was recently reported to be a promising novel antischistosomal therapy with potent in vivo activity against Schistosoma mansoni. In this work, we report the in vitro dose- and time-response effect of CO-ArNp against the Egyptian strain of S. mansoni, and its snail host, Biomphalaria alexandrina. Incubation of adult S. mansoni with CO-ArNp at 40 or 20 ?g/ml for 48 or 72 h killed all worms. Exposure of S. mansoni miracidia and cercariae to the molluscicidal LC50 of CO-ArNp (16.8 ?g/ml) resulted in 100% mortality of the free larval stages within 90 and 15 min, respectively. Moreover, incubation of adult B. alexandrina snails with this drug combination killed all snails at 40 ?g/ml within 24h. Scanning electron microscope revealed marked morphological and tegumental alterations on the different stages of the parasite and its snail soft tissue. Our study highlights the schistosomicidal and molluscicidal effects of artemisinin-naphthoquine phosphate. No doubt more studies are needed to clarify its potential value to control schistosomiasis. PMID:25291045

El-Beshbishi, Samar N; El Bardicy, Samia; Tadros, Menerva; Ayoub, Magda; Taman, Amira

2015-01-01

5

Molluscicidal Activity of the Methanol Extract of Callistemon viminalis (Sol. ex Gaertner) G.Don ex Loudon Fruits, Bark and Leaves against Biomphalaria alexandrina Snails  

PubMed Central

Methanol extracts of Callistemon viminalis (Sol. Ex Gaertner) G.Don Ex Loudon fruits, bark and leaves were tested for molluscicidal activity. Snails were collected and kept in dechlorinated water under standard condition. Ten adults Biomphalaria Alexandrina, of the same size, were introduced in plastic acquaria for each experiment. The fruits, barks and leaves were extracted with methanol and the methanol extracts were kept for testing as molluscicides. Different extracts proved to have molluscicidal activity against the vector of schistosomiasis, B. alexandrina snails. LC50 values for C. viminalis fruits, bark and leaves were 6.2, 32 and 40 ppm respectively. The C. viminalis fruits extract showed the highest effect against the tested snails. Histopathological studies proved that the site of action of all tested extracts was localized in the digestive system and hermaphrodite gland. PMID:25237345

A Gohar, Ahmed; T Maatooq, Galal; R Gadara, Sahar; S Aboelmaaty, Walaa; M El-Shazly, Atef

2014-01-01

6

Biological and biochemical studies on Biomphalaria alexandrina snails, treated with low concentrations of certain molluscicides (synthetic and of plant origin).  

PubMed

The effect of low concentrations of different synthetic and natural mollusciciding agents may introduce to fresh water environment on reproduction and biochemical aspects of Biomphalaria alexandrina was studied. Different mollusciciding agents (copper sulphate, Bayluscide, Uccmaluscide, Agave filifera & A. attenuate) inhibited egg production, induced marked increased the percent of abnormal laid eggs and induced marked reduction in their hatchability. The maximal reductions in egg hatchability resulted with Bayluscide (0.0%) and Uccmaluscide (18%), A. filifera (21%) and A. attenuata (15%). All the antimolluscal materials caused a successful killing effect against miracidia and cercariae of Schistosoma mansoni. CuSo4, Bayluscide and Uccmaluscide killed 40% of the exposed miracidia and 50% of cercariae after an hour exposure. The plants sublethal concentration killed 100% of cercariae and miracidia after 6 hours exposure. Water leaving behaviour among the exposed snails was noticed especially during the first three weeks, showing maximal percentage (60%) after one week of exposure to Bayluscide. A general decrease in the activity of alkaline phosphatase (ALP) especially with Bayluscide (48.4%) and in acetylcholine esterase activity in the haemolymph especially on applying plant molluscicide A. filifera (50.8%) was noticed. Transaminases showed marked elevations in activities during the 1st three weeks, then began to drop (ASAT: 61.5%, with Bayluscide & ALAT: 50.8% with Uccmaluscide). The results reflect the effect of the metabolic disorders on life, egg laying, egg hatchability, hepatic cells damages, lack of smooth transmission at nerve junction, loss of muscular coordination and convulsions, then snails' death. PMID:16333894

Abdel Kader, Ahmed; Hamdi, Salwa A H; Rawi, Sayed M

2005-12-01

7

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

PubMed

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

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

2014-12-01

8

Characterization of Biomphalaria alexandrina-derived lectins recognizing a fucosyllactose-related determinant on schistosomes  

Microsoft Academic Search

Two novel lectins that bind selectively to a schistosome-associated fucosyllactose-related determinant have been characterized and purified from the hemolymph of Biomphalaria alexandrina, the snail vector of Schistosoma mansoni. Both lectins were purified by affinity chromatography on a column of equimolar mixture of d- and l-glucose coupled to epoxy-activated Sepharose 6B and sequential elution by d-glucose (designated BaSI) and l-fucose (designated

Mohamed H. Mansour; Hoda I. Negm; Abdel Hakim Saad; Nagwa I. Taalab

1995-01-01

9

Induced Changes in the Amino Acid Profile of Biomphalaria alexandrina Molluscan Host to Schistosoma mansoni Using Sublethal Concentrations of Selected Plant Molluscicides  

NASA Astrophysics Data System (ADS)

Amino acid profiles of control and Solanum nigrum, Ambrosia maritima, Thymelaea hirsute, Sinapis arvensis, Peganum haramala and Callistemon lanceolatus-treated Biomphalaria alexandrina snails were investigated in a trial to correlate the amino acid profile of treated snails to their previously reported molluscicidal and biological effects. Amino acid profiles of the snails were greatly manipulated with the treatment of dry powdered sublethal concentrations of the six studied plant molluscicides. The disturbed amino acid profiles of treated snails were discussed in relation to the decrease in snail's egg laying capacity, reduction of their compatibility for the development of the schistosome larvae and cercarial penetration of mammalian skin.

Sanad Soliman, Mahmoud; El-Ansary, Afaf

10

Bioactivity of Anagallis arvensis and Calendula micrantha plants, treated with ammonium nitrate, superphosphate and potassium sulphate fertilizers, on Biomphalaria alexandrina.  

PubMed

The survival rate of B. alexandrina snails maintained in aqueous solutions of the two tested plants (Calendula micrantha and Anagallis arvensis) decreased gradually with time until the 9th week and 10th week where the survival rate was zero in the high concentration of A. arvensis and C. micrantha, respectively, meanwhile, the survival rate of the control was 20%. Also, the two plants caused reduction in hatchability of snails egg masses. Thus, the percent of hatching in A. arvensis (82 ppm) was 46% and in C. micrantha was 72% compared with control (97.29%). Both plants reduced the infection rate of Biomphalaria alexandrina snails with Schistosoma mansoni miracidia to 41.17% and 61.9%, respectively, compared with control (90%). C. micrantha caused much higher reduction in snail infection rate than A. arvensis. The prepatent period was significantly prolonged in snails maintained at higher concentration of both plants. The cercarial output (expressed as mean number/snail) revealed that, A. arevensis caused a significant reduction in cercarial production than control. While, high concentration (120 ppm) of C. micrantha caused a significant elevation in the mean number of cercariae/snail. However, the total number of cercariae produced by all snails in each group showed a reverse relation with the tested concentrations in both plants. PMID:11198390

Mostafa, B B; Tantawy, A A

2000-12-01

11

Localization of tyrosine hydroxylase-like immunoreactivity in the nervous systems of Biomphalaria glabrata and Biomphalaria alexandrina, intermediate hosts for schistosomiasis.  

PubMed

Planorbid snails of the genus Biomphalaria are major intermediate hosts for the digenetic trematode parasite Schistosoma mansoni. Evidence suggests that levels of the neurotransmitter dopamine (DA) are reduced during the course of S. mansoni multiplication and transformation within the snail. This investigation used immunohistochemical methods to localize tyrosine hydroxylase (TH), the rate-limiting enzyme in the biosynthesis of catecholamines, in the nervous system of Biomphalaria. The two species examined, Biomphalaria glabrata and Biomphalaria alexandrina, are the major intermediate hosts for S. mansoni in sub-Saharan Africa, where more than 90% of global cases of human intestinal schistosomiasis occur. TH-like immunoreactive (THli) neurons were distributed throughout the central nervous system (CNS) and labeled fibers were present in all commissures, connectives, and nerves. Some asymmetries were observed, including a large distinctive neuron (LPeD1) in the pedal ganglion described previously in several pulmonates. The majority of TH-like immunoreactive neurons were detected in the peripheral nervous system (PNS), especially in lip and foot regions of the anterior integument. Independent observations supporting the dopaminergic phenotype of THli neurons included 1) block of LPeD1 synaptic signaling by the D2/3 antagonist sulpiride, and 2) the similar localization of aqueous aldehyde (FaGlu)-induced fluorescence. The distribution of THli neurons indicates that, as in other gastropods, dopamine functions as a sensory neurotransmitter and in the regulation of feeding and reproductive behaviors in Biomphalaria. It is hypothesized that infection could stimulate transmitter release from dopaminergic sensory neurons and that dopaminergic signaling could contribute to modifications of both host and parasite behavior. PMID:24477836

Vallejo, Deborah; Habib, Mohamed R; Delgado, Nadia; Vaasjo, Lee O; Croll, Roger P; Miller, Mark W

2014-08-01

12

Biomphalaria species in Alexandria water channels.  

PubMed

Of the several species of Biomphalaria snails worldwide that serve as the intermediate host for Schistosoma mansoni, Biomphalaria alexandrina is a species that is indigenous to Egypt. Recently, there has been much debate concerning the presence of Biomphalaria glabrata and the hybrid of the species with Biomphalaria alexandrina. Due to this debate, the absence of a clear explanation for the presence of B. glabrata in Egyptian water channels and the probability that they may be reintroduced, we conducted this field study to identify Biomphalaria species present in Alexandria water channels. Laboratory-adapted susceptible snails to Schistosoma mansoni of the following species were used as a reference; Biomphalaria alexandrina, Biomphalaria glabrata and their hybrid. These snails were used to perpetuate the Schistosoma life cycle at the Theodor Bilharz Research Institute (TBRI), Cairo, Egypt. Morphological and molecular studies were conducted on these reference snails as well as on the first generation of Biomphalaria snails from two areas in the Alexandria governorate. The morphological study included both external shell morphology and internal anatomy of the renal ridge. The molecular study used a species-specific PCR technique. The results demonstrated that there was an absence of Biomphalaria glabrata and the hybrid from Alexandria water channels. Moreover, the susceptibility patterns of these reference snails were studied by measuring the different parasitological parameters. It was found that Biomphalaria glabrata and the hybrid were significantly more susceptible than Biomphalaria alexandrina to the Egyptian strain of Schistosoma mansoni. The results demonstrated that if Biomphalaria glabrata was reintroduced and adapted to the local environment in Egypt, it would have important epidemiologic impacts that would have a serious effect on the health of Egyptian people. PMID:21458594

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

2011-09-01

13

Distinct binding patterns of fucose-specific lectins from Biomphalaria alexandrina and Lotus tetragonolobus to murine lymphocyte subsets  

Microsoft Academic Search

The putative expression of distinct terminally fucosylated glycoconjugates among murine lymphocyte subpopulations was sought using a Biomphalaria alexandrina-derived lectin (BaSI), of proven specificity to a fucosyllactose determinant, and the fucose-binding lectin from Lotus tetragonolobus seeds. Direct labeling of isolated lymphocyte subsets in suspension as well as immuno-histochemical and two-dimensional Western blotting assays demonstrated the exclusive expression of the BaSI-reactive ligand

Mohamed H. Mansour; Fatma Abdul-Salam; Tahany Al-Shemary

2005-01-01

14

Semi field trials to control Biomphalaria alexandrina by different modes of exposure to certain plant and chemical molluscicides.  

PubMed

Semi-field trials were carried out in Snail Research Station under simulated natural conditions to evaluate different modes of exposure to Anagallis arvensis and Calendula micrantha as plant molluscicides and bayluscide and copper sulphate as chemical molluscicides. Firstly, B. alexandrina were exposed to the tested molluscicides alone and in addition to two densities of aquatic plants. No apparent effect of aquatic plants on the activity of both plant and chemical molluscicides, this may be due that the two densities of the aquatic plants used were insufficient to interfere with the molluscicides action. Secondly, snails were pre-exposed to three sub-lethal concentrations of the plant molluscicides for 24h then to three concentrations of the chemical molluscicides and vice versa. The results indicate that the pre-exposure increases the snail mortality significantly in all treatments of bayluscide and A. arvensis (except in the highest concentration when the snails firstly exposed to bayluscide then to A. arvensis, where the two compared treatment showed 100%) and in all treatments of bayluscide and C. micrantha. Also, in one treatment of copper sulphate and A. arvensis (in the highest concentration when the snails firstly exposed to A. arvensis then to copper sulphate) and in three treatments of copper sulphate and C. micrantha, (in least and moderate concentrations when snails firstly exposed to C. micrantha then to copper sulphate and in the highest concentration when snails firstly exposed to copper sulphate then to C. micrantha). Thirdly, snails were exposed to mixtures of six different ratios of bayluscide and each of A. arvensis and C. micrantha. The results indicated that the snail mortality increased significantly only in the first treatment of bayluscide and A. arvensis mixtures and in treatment number 6 of bayluscide and C. micrantha. PMID:16333900

Mostafa, Bayaumy B; el-Khayat, Hanaa M M; Ragab, Fawzy M A; Tantawy, Ahmed A A

2005-12-01

15

Distinct binding patterns of fucose-specific lectins from Biomphalaria alexandrina and Lotus tetragonolobus to murine lymphocyte subsets.  

PubMed

The putative expression of distinct terminally fucosylated glycoconjugates among murine lymphocyte subpopulations was sought using a Biomphalaria alexandrina-derived lectin (BaSI), of proven specificity to a fucosyllactose determinant, and the fucose-binding lectin from Lotus tetragonolobus seeds. Direct labeling of isolated lymphocyte subsets in suspension as well as immuno-histochemical and two-dimensional Western blotting assays demonstrated the exclusive expression of the BaSI-reactive ligand among multiple isoforms of two major 95 and 92 kDa and a minor 82 kDa acidic glycoproteins, selectively localized to the splenic marginal zone B lymphocytes of adult mice. The expression of the L. tetragonolobus lectin-reactive ligand was, on the other hand, restricted primarily to a single homogeneous 50 kDa acidic glycoprotein associated with a subset of the mature (PNA-) medullary thymocytes of adult mice as well as a minority of the immature (PNA +) thymocytes within the deep cortical region in newly born mice. The significance of these findings is discussed in relation to mechanisms that govern lymphocyte development and homing. PMID:16164040

Mansour, Mohamed H; Abdul-Salam, Fatma; Al-Shemary, Tahany

2005-01-01

16

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

Microsoft Academic Search

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

R. Slootweg

1987-01-01

17

Molluscicidal activity of some Saudi Arabian euphorbiales against the snail Biomphalaria pfeifferi.  

PubMed

The comparative susceptibility of the snail vector of intestinal schistosomiasis, Biomphalaria pfeifferi to the action of extracts from Saudi Arabian Euphorbiales has been determined. Methanol and chloroform extracts of the plants tested (Jatropha glauca, Euphorbia helioscopia and Euphorbia schimperiana) were the most promising from the molluscicidal point of view with LD(50) values in the range 10-100 ppm. PMID:10771201

Al-Zanbagi, N A; Banaja, A A; Barrett, J

2000-05-01

18

Molluscicidal activity of some Saudi Arabian Euphorbiales against the snail Biomphalaria pfeifferi  

Microsoft Academic Search

The comparative susceptibility of the snail vector of intestinal schistosomiasis, Biomphalaria pfeifferi to the action of extracts from Saudi Arabian Euphorbiales has been determined. Methanol and chloroform extracts of the plants tested (Jatropha glauca, Euphorbia helioscopia and Euphorbia schimperiana) were the most promising from the molluscicidal point of view with LD50 values in the range 10–100 ppm.

Najia A Al-Zanbagi; Abdul-Elah A Banaja; John Barrett

2000-01-01

19

Measurement of Selected Enzymatic Activities in Solanum nigrum-Treated Biomphalaria arabica Snails  

NASA Astrophysics Data System (ADS)

In the present study, glucose, acid and alkaline phosphatases (ACP and ALP), ?-amylase and lipase were measured for the first time in tissue homogenates of Biomphalaria arabica snails, molluscan intermediate host for Schistosoma mansoni in Saudi Arabia. Also, the effect of sublethal concentrations (LC25) of dry powdered Solanum nigrum leaf was tested as plant molluscicide against this snail species. The tested enzymes were altered in molluscicide-treated snails compared to control. While ALP and amylase were slightly affected, ACP and lipase were significantly altered. Glucose as an important energy source for a successful schistosome-snail relationship was significantly reduced in molluscicide-treated snails. In conclusion, sublethal concentration of the molluscicide showed potent effect in disturbing snail biochemistry which may render them physiologically unsuitable for the developing of schistosome parasite. This could be considered as a promising strategy to control the disease.

Al-Daihan, Sooad

20

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

PubMed

In order to investigate the capacity of being intermediate host for Schistosoma mansoni, the Ugandan F1 generation of Biomphalaria snail species that were laboratory-bred from parent populations originally collected from either Lake Victoria or Lake Albert was challenged with sympatric and non-sympatric S. mansoni isolates. After a prepatent period of 20 days, a daily 10-hourly snail shedding for cercariae was done to determine the infection rate, cercarial production per hour and survival period of infected snails. The study suggests that when parasite strains from a different geographical origin is used for infection, survival of infected snails increase, leading to an increased transmission potential. Although earlier literature had indicated that the Lake Victoria Biomphalaria sudanica is refractory to S. mansoni, we showed that all Ugandan Biomphalaria spp., including B. sudanica from all locations, were highly susceptible to the S. mansoni isolates. Thus if B. choanomphala, which is an efficient intermediate host in Lake Victoria, is given an opportunity to occupy Lake Albert, it will most likely be compatible with the Albertine S. mansoni parasites. Equally, if B. stanleyi, currently restricted to Lake Albert invades Lake Victoria, it is likely to act as an efficient intermediate host. Future work should concentrate on intraspecific population-level differences in compatibility. PMID:23454225

Adriko, Moses; Standley, Claire J; Tinkitina, Benjamin; Mwesigwa, Gerald; Kristensen, Thomas K; Stothard, J Russell; Kabatereine, Narcis B

2013-11-01

21

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

PubMed Central

Biomphalaria glabrata snails that display either resistant or susceptible phenotypes to the parasitic trematode, Schistosoma mansoni provide an invaluable resource towards elucidating the molecular basis of the snail-host/schistosome relationship. Previously, we showed that induction of stress genes either after heat-shock or parasite infection was a major feature distinguishing juvenile susceptible snails from their resistant counterparts. In order to examine this apparent association between heat stress and snail susceptibility, we investigated the effect of temperature modulation in the resistant snail stock, BS-90. Here, we show that, incubated for up to 4 hrs at 32°C prior to infection, these resistant snails became susceptible to infection, i.e. shedding cercariae at 5 weeks post exposure (PE) while unstressed resistant snails, as expected, remained resistant. This suggests that susceptibility to infection by this resistant snail phenotype is temperature-sensitive (ts). Additionally, resistant snails treated with the Hsp 90 specific inhibitor, geldanamycin (GA) after heat stress, were no longer susceptible to infection, retaining their resistant phenotype. Consistently, susceptible snail phenotypes treated with 100 mM GA before parasite exposure also remained uninfected. These results provide direct evidence for the induction of stress genes (heat shock proteins; Hsp 70, Hsp 90 and the reverse transcriptase [RT] domain of the nimbus non-LTR retrotransposon) in B. glabrata susceptibility to S. mansoni infection and characterize the resistant BS-90 snails as a temperature-sensitive phenotype. This study of reversing snail susceptibility phenotypes to S. mansoni provides an opportunity to directly track molecular pathway(s) that underlie the B. glabrata snail's ability to either sustain or destroy the S. mansoni parasite. PMID:22577362

Ittiprasert, Wannaporn; Knight, Matty

2012-01-01

22

Purification and characterization of SM 37: a fucosyllactose determinant-bearing glycoprotein probed by a Biomphalaria alexandrina lectin on adult male schistosomes.  

PubMed

Utilizing a Biomphalaria alexandrina-derived lectin (BaSII) of proven specificity to a Schistosoma mansoni-associated fucosyllactose [(Fuc alpha 1-2)Gal beta 1-4 Glc] determinant, a 37-kDa determinant-bearing glycoprotein (Sm 37) was identified selectively on adult male schistosomes. Sm 37 was purified to homogeneity from extracts of adult male worms metabolically radiolabeled with [35S] methionine by BaSII affinity chromatography followed by separation on an HPLC column. Treatments with endoglycosidases, alkaline borohydride, as well as serial lectin affinity chromatography and analysis on 2-dimensional gels indicated that Sm 37 is synthesized as a 33-kDa polypeptide backbone that expresses the fucosyllactose determinant on the outer chain of a single N-linked complex-type glycan unit of either the biantennary or, to a lesser extent, the tri- or tetra-antennary types. The distinct structures of the complex oligosaccharides accounted for the expression of 2 isomorphs of Sm 37. the glycoprotein lacks other conventional high mannose-type or O-linked oligosaccharides and, as deduced from the N-terminal amino acid sequence, the Sm 37 polypeptide may be distinct from other schistosome polypeptides of known sequence. Based on the structural relatedness of the Sm 37-associated fucosyllactose determinant to the antigenic blood group H trisaccharide, these observations may have implications for mechanisms of these host-parasite interactions. PMID:8691365

Mansour, M H

1996-08-01

23

Evidence for a family of schistosome glycan-binding lectins in Biomphalaria afexandrina  

Microsoft Academic Search

A novel family of isolectins that selectively recognize a schistosome-associated fucosyllactose determinant was identified in the hemolymph of Biomphalaria alexandrina, a snail vector of Schistosoma mansoni. Three lectins of this family were purified by serial affinity chromatography on a column of l-fucose and elution with a gradient of 0.1-1 Ml-fucose (designated BaSII and BaSIII), followed by a column of d-glucose

Mohamed H. Mansour

1995-01-01

24

Determination and quantification of Schistosoma mansoni cercarial emergence from Biomphalaria glabrata snails.  

PubMed

Living and fixed samples of Schistosoma mansoni -infected Biomphalaria glabrata snails were used to determine the relative contributions of different snail tissues to cercarial emergence (shedding). Three methods of observations were employed: (1) direct microscopical observations of shedding snails; (2) microscopic analysis of 5 ?m serial sections (H&E stained) of actively shedding snails; and (3) scanning electron microscopic (SEM) observations of snails that were fixed while actively shedding. For this investigation, there were advantages and disadvantages to using each method. We confirmed the results of others that there were 3 tissues of the snail that contributed most prominently to cercarial release (mantle collar, pseudobranch, and headfoot). Based on histological analysis of cercarial accumulations in presumed shedding sites in these 3 tissues, 57% of the cercariae could be seen in the mantle collar, 30.6% in the pseudobranch, and 12.5% in the headfoot. Other anterior structures were involved to a much lesser extent. SEM observations clearly showed cercariae emerging either body first, tail first, or likely emerging en masse from blebs, especially from the mantle collar. These studies provide a more quantitative appraisal of the role the different anterior snail tissues play in cercarial emergence. PMID:25019357

Tucker, Matthew S; Lewis, Fred A; Driver, James D; Granath, Willard O

2014-12-01

25

Characterization of fucosyllactose determinant-bearing glycoproteins probed by a Biomphalaria alexandrina lectin in Schistosoma mansoni cercariae  

Microsoft Academic Search

Utilizing a Biomphalaria alex-andrina-derived lectin (BaSII) of proven specificity to a Schistosoma mansoni-associated fucosyllactose [(Fuc ?1–2) Gal ?1–4 Glc] determinant, two determinant-bearing glycoproteins of 40 and 37 kDa were found to be synthesized by the cercarial stage of the parasite. The two glycoproteins were isolated by BaSII affinity column chromatography from extracts of cercariae metabolically radiolabelled with 35S-methionine. Treatments with

Hoda I. Negm

1996-01-01

26

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

NASA Technical Reports Server (NTRS)

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

Gao, Wenyuan; Wiederhold, Michael; Hejl, Robert

1997-01-01

27

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

Microsoft Academic Search

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

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

28

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

PubMed

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

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

2014-01-01

29

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

PubMed

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

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

2004-08-01

30

Schistosoma mansoni infection of juvenile Biomphalaria glabrata induces a differential stress response between resistant and susceptible snails  

PubMed Central

Schistosomes develop successfully in susceptible snails but are encapsulated and killed in resistant ones. Mechanism(s) shaping these outcomes involves the parasites ability to evade the snail’s defenses. RNA analysis from resistant (BS-90), non-susceptible (LAC2) and susceptible (NMRI) juvenile Biomphalaria glabrata to Schistosoma mansoni revealed that stress related genes, heat shock protein 70 (Hsp 70) and reverse transcriptase (RT), were dramatically co-induced early in susceptible snails, but not in resistant/non-susceptible ones. These transcripts were, however, down regulated upon exposure to irradiated parasites although penetration behavior of irradiated vs normal parasites were the same, indicating that Hsp 70 regulation was elicited by infection and not injury. Understanding molecular events involved in stress response transcriptional regulation of Hsp 70 in juvenile snails could pave a way towards the identification of genes involved in schistosome/snail interactions. PMID:19660454

Ittiprasert, Wannaporn; Nene, Rahul; Miller, André; Raghavan, Nithya; Lewis, Fred; Hodgson, Jacob; Knight, Matty

2009-01-01

31

Schistosomin from the snail Biomphalaria glabrata: Expression studies suggest no involvement in trematode-mediated castration  

PubMed Central

By inhibiting reproductive hormones, the neuropeptide schistosomin produced by the snail Lymnaea stagnalis plays an essential role in parasitic castration mediated by the schistosome parasite Trichobilharzia ocellata during late stage infection. Here we report on the presence and expression of schistosomin in the snail Biomphalaria glabrata, a prominent intermediate host of the parasite Schistosoma mansoni, one of the causative agents of human schistosomiasis. The deduced amino acid (aa) sequences from complementary DNAs (cDNAs) from B. glabrata contain a 17 aa signal peptide and a 79 aa mature peptide with 62–64% identity to schistosomin from L. stagnalis. Ontogenic expression at the protein and mRNA levels showed that schistosomin was in higher abundance in embryos and juveniles relative to mature snails, suggesting that schistosomin is likely involved in developmental processes, not in reproduction. Moreover, expression data demonstrated that infection with two different digenetic trematodes, S. mansoni and Echinostoma paraensei, did not provoke elevated expression of schistosomin in B. glabrata from early stage infection (4 days post exposure; dpe) to patent infection (up to 60 dpe), by which time parasitic castration has been accomplished. In conclusion, our data suggest that a role of schistosomin in parasitic castration cannot be established in B. glabrata infected with either of two trematode species. PMID:19393164

Zhang, Si-Ming; Nian, Hong; Wang, Bo; Loker, Eric S.; Adema, Coen M

2013-01-01

32

Regulation of hydrogen peroxide release in circulating hemocytes of the planorbid snail Biomphalaria glabrata  

PubMed Central

Biomphalaria spp. serve as obligate intermediate hosts for the human blood fluke Schistosoma mansoni. Following S. mansoni penetration of Biomphalaria glabrata, hemocytes of resistant snails migrate towards the parasite, encasing the larva in a multicellular capsule resulting in its destruction via a cytotoxic reaction. Recent studies have revealed the importance of hydrogen peroxide and nitric oxide (H2O2, NO) in parasite killing [1, 2]. It is assumed H2O2 and NO production is tightly regulated although the specific molecules involved remain largely unknown. Consequently, the potential role of cell signaling pathways in B. glabrata hemocyte H2O2 production was investigated by evaluating the effects of specific inhibitors of selected signaling proteins. Results suggest that both ERK and p38 MAPKs are involved in the regulation of B. glabrata H2O2 release in response to stimulation by PMA and galactose-conjugated BSA. However, the involvement of the signaling proteins PKC, PI3 kinase and PLA2 differs between PMA- and BSA-gal-induced H2O2 production. PMID:17981329

Humphries, Judith E.; Yoshino, Timothy P.

2008-01-01

33

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

NASA Technical Reports Server (NTRS)

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

Gao, Wenyuan; Wiederhold, Michael L.

1997-01-01

34

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

PubMed

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

Roberts, J K; Kuris, A M

1990-08-01

35

Study of the snail intermediate hosts for Schistosoma mansoni on Itamaracá Island in northeast Brazil: spatial displacement of Biomphalaria glabrata by Biomphalaria straminea.  

PubMed

In 2012 a malacological survey of the breeding sites of Biomphalaria glabrata and B. straminea , the two intermediate host snails of Schistosoma mansoni , was carried out on Itamaraca Island in Pernambuco, Brazil. This study has now been extended by studying the competition between the two species. Snails were collected and dissected to identify the species and tests were performed to verify S. mansoni infection. Student's t test was used to compare the proportion between the two species and their breeding sites and a parasitological survey was conducted among local residents, using the Kato-Katz method. The spatial distribution of the two snail species was determined using TerraView, while a snail density map was constructed by Kernel estimate. The survey identified two breeding sites for B. glabrata with 17 specimens and 19 breeding sites for B. straminea with 459 snails, all of them negative for S. mansoni infection. The statistical analysis revealed that the proportion of the numbers of specimens and breeding sites of B. straminea (37.84 ± 9.01) were significantly greater than those of B. glabrata (8.50 ± 6.50). Parasitological examinations from 41 residents diagnosed two cases of schistosomiasis with parasite loads of 60 and 84 eggs per 1 g of stool, respectively. This indiction of a competitive process between the two snail species requires monitoring of schistosomiasis in the resident and travelling human populations occupying this environment, which could potentially result in social and economic changes on the island risking its attraction as a centre for eco-tourism. PMID:24893012

Barbosa, Constança S; Barbosa, Verônica S; Nascimento, Wheverton C; Pieri, Otavio S; Araújo, Karina C G M

2014-05-01

36

Schistosoma mansoni in Susceptible and Resistant Snail Strains Biomphalaria tenagophila: In Vivo Tissue Response and In Vitro Hemocyte Interactions  

PubMed Central

Schistosomiasis is a parasitic disease that is highly prevalent, especially in developing countries. Biomphalaria tenagophila is an important invertebrate host of Schistosoma mansoni in Brazil, with some strains (e.g. Cabo Frio) being highly susceptible to the parasite, whereas others (e.g. Taim) are completely resistant to infection. Therefore, B. tenagophila is an important research model for studying immune defense mechanisms against S. mansoni. The internal defense system (IDS) of the snail comprises hemocytes and hemolymph factors acting together to recognize self from non-self molecular patterns to eliminate the threat of infection. We performed experiments to understand the cellular defenses related to the resistance and/or susceptibility of B. tenagophila to S. mansoni. During the early stages of infection, fibrous host cells of both snail strains were arranged as a thin layer surrounding the sporocysts. However, at later stages of infection, the cellular reactions in resistant snails were increasingly more intense, with thicker layers surrounding the parasites, in contrast to susceptible strains. All parasites were damaged or destroyed inside resistant snails after 10 h of infection. By contrast, parasites inside susceptible snails appeared to be morphologically healthy. We also performed experiments using isolated hemocytes from the two strains interacting with sporocysts. Hemocyte attachment started as early as 1 h after initial infection in both strains, but the killing of sporocysts was exclusive to hemocytes from the resistant strain and was time course dependent. The resistant strain was able to kill all sporocysts. In conclusion, our study revealed important aspects of the initial process of infection related to immune defense responses of strains of B. tenagophila that were resistant to S. mansoni compared with strains that were susceptible. Such information is relevant for the survival or death of the parasites and so is important in the development of control measures against this parasite. PMID:23049828

Nacif-Pimenta, Rafael; de Mattos, Ana Carolina Alves; Orfanó, Alessandra da Silva; Barbosa, Luciene; Pimenta, Paulo Filemon Paolucci; Coelho, Paulo Marcos Zech

2012-01-01

37

Fucoidan stimulates cell division in the amebocyte-producing organ of the schistosome-transmitting snail Biomphalaria glabrata.  

PubMed

Adult Salvador (schistosome-resistant) strain Biomphalaria glabrata snails were injected with 5 ?l of 10 mg/ml solutions of the sulfated polysaccharides ? carageenan, dextran sulfate, fucoidan, and heparin, the nonsulfated polysaccharide laminarin, and the monosaccharides L-fucose and L-galactose, and mitotic activity in the amebocyte-producing organ (APO) was measured in histological sections at 24 h post injection. Among the substances tested, only fucoidan induced elevated mitotic activity. Desulfated fucoidan was not mitogenic, indicating that sulfate groups are required for activity. Schistosome-susceptible M-line snails possessed minimal or no hematopoietic tissue in their APO, which did not respond to fucoidan. Immersion of juvenile Salvador snails in 1 or 10 mg/ml solutions of fucoidan for 3 h did not elevate mitotic activity at 24 h post immersion, suggesting that the external and digestive tract epithelia of B. glabrata are impermeable to this molecule. These results provide support for the hypothesis that fucosylated glycans on the tegument and in excretory-secretory products of sporocysts of Schistosoma mansoni are in part responsible for increased mitotic activity in the APO of B. glabrata infected with this trematode or injected with its extracts. PMID:25233872

Sullivan, John T; Belloir, Joseph A; Beltran, Roxxana V; Grivakis, Aris; Ransone, Kathryn A

2014-11-01

38

The spatial and seasonal distribution of Bulinus truncatus, Bulinus forskalii and Biomphalaria pfeifferi, the intermediate host snails of schistosomiasis, in N'Djamena, Chad.  

PubMed

There is a paucity of epidemiological and malacological data pertaining to schistosomiasis in Chad. In view of a recently articulated elimination agenda, a deeper understanding of the spatio-temporal distribution of schistosomiasis intermediate host snails is pivotal. We conducted cross-sectional malacological surveys during the dry season (April/May 2013) and after the short rainy season (October 2013) in N'Djamena, the capital of Chad. Snails were identified at the genus and species level using morphological keys and molecular DNA barcoding approaches. Those belonging to Bulinus and Biomphalaria were examined for cercarial shedding. Snail habitats were characterised and their predictive potential for the presence of schistosomiasis intermediate host snails explored. Seasonal patterns were studied using geographical information system and kriging in order to interpolate snail abundance data to make predictions at non-sampled locations across N'Djamena. Overall, 413 Bulinus truncatus, 369 Bulinus forskalii and 108 Biomphalaria pfeifferi snails were collected and subjected to cercarial shedding. During the dry season, one Bu. truncatus of 119 snails collected shed Schistosoma spp. cercariae (0.84%), while S. mansoni was shed by one of 108 Bi. pfeifferi snails (0.93%). None of the snails collected after the rainy season shed Schistosoma spp. cercariae. The abundance of Bu. truncatus and Bu. forskalii showed an inverse U-shape relationship with the square term of conductivity, i.e. low abundance at the lowest and highest levels of conductivity and high abundance at intermediate levels. Bi. pfeifferi showed a negative, linear association with pH in the dry seasons. It is planned to link these intermediate host snail data to infection data in human populations with the goal to draw a predictive risk map that can be utilised for control and elimination of schistosomiasis in N'Djamena. PMID:25545929

Moser, Wendelin; Greter, Helena; Schindler, Christian; Allan, Fiona; Ngandolo, Bongo N R; Moto, Daugla D; Utzinger, Jürg; Zinsstag, Jakob

2014-11-01

39

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

PubMed Central

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

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

2013-01-01

40

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

PubMed Central

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

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

2009-01-01

41

Bibliotheca Alexandrina  

NSDL National Science Digital Library

The ancient library at Alexandria was rightfully one of the Seven Wonders of the Ancient World and its spirit and commitment to the pursuit of learning is embodied in the modern Bibliotheca Alexandrina in Egypt. As their mission statement notes, the library is to be "a center for dialogue between peoples and civilizations". This is no easy feat, and the web-browsing public can learn about their laudable efforts on this website. Visitors may first want to learn about the remarkable structure that houses the library, along with a variety of facts about this building's construction. While visitors who may be planning a visit to Egypt may wish to learn about tours of the building and the ways in which they may utilize their research collections, others may want to peruse the "Initiatives" area. Here they will find links to some of their digital projects, which include "Eternal Egypt", which offers an extremely media-rich site that allows visitors to explore over 5000 years of Egyptian civilization through timelines, objects, and interactive maps.

42

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

PubMed

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

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

2014-12-01

43

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

PubMed Central

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

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

2013-01-01

44

The Effect of Simulating Different Intermediate Host Snail Species on the Link between Water Temperature and Schistosomiasis Risk  

PubMed Central

Introduction A number of studies have attempted to predict the effects of climate change on schistosomiasis risk. The importance of considering different species of intermediate host snails separately has never previously been explored. Methods An agent-based model of water temperature and Biomphalaria pfeifferi population dynamics and Schistosoma mansoni transmission was parameterised to two additional species of snail: B. glabrata and B. alexandrina. Results Simulated B. alexandrina populations had lower minimum and maximum temperatures for survival than B. pfeifferi populations (12.5–29.5°C vs. 14.0–31.5°C). B. glabrata populations survived over a smaller range of temperatures than either B. pfeifferi or B. alexandrina (17.0°C–29.5°C). Infection risk peaked at 16.5°C, 25.0°C and 19.0°C respectively when B. pfeifferi, B. glabrata and B. alexandrina were simulated. For all species, infection risk increased sharply once a minimum temperature was reached. Conclusions The results from all three species suggest that infection risk may increase dramatically with small increases in temperature in areas at or near the currents limits of schistosome transmission. The effect of small increases in temperature in areas where schistosomiasis is currently found will depend both on current temperatures and on the species of snail acting as intermediate host(s) in the area. In most areas where B. pfeifferi is the host, infection risk is likely to decrease. In cooler areas where B. glabrata is the host, infection risk may increase slightly. In cooler areas where B. alexandrina is the host, infection risk may more than double with only 2°C increase in temperature. Our results show that it is crucial to consider the species of intermediate host when attempting to predict the effects of climate change on schistosomiasis. PMID:24988377

McCreesh, Nicky; Booth, Mark

2014-01-01

45

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

PubMed Central

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

Lafferty, Kevin D.; Kuris, Armand M.

2014-01-01

46

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

PubMed

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

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

2014-04-01

47

Acetylcholine-Binding Protein in the Hemolymph of the Planorbid Snail Biomphalaria glabrata Is a Pentagonal Dodecahedron (60 Subunits)  

PubMed Central

Nicotinic acetylcholine receptors (nAChR) play important neurophysiological roles and are of considerable medical relevance. They have been studied extensively, greatly facilitated by the gastropod acetylcholine-binding proteins (AChBP) which represent soluble structural and functional homologues of the ligand-binding domain of nAChR. All these proteins are ring-like pentamers. Here we report that AChBP exists in the hemolymph of the planorbid snail Biomphalaria glabrata (vector of the schistosomiasis parasite) as a regular pentagonal dodecahedron, 22 nm in diameter (12 pentamers, 60 active sites). We sequenced and recombinantly expressed two ?25 kDa polypeptides (BgAChBP1 and BgAChBP2) with a specific active site, N-glycan site and disulfide bridge variation. We also provide the exon/intron structures. Recombinant BgAChBP1 formed pentamers and dodecahedra, recombinant BgAChBP2 formed pentamers and probably disulfide-bridged di-pentamers, but not dodecahedra. Three-dimensional electron cryo-microscopy (3D-EM) yielded a 3D reconstruction of the dodecahedron with a resolution of 6 Å. Homology models of the pentamers docked to the 6 Å structure revealed opportunities for chemical bonding at the inter-pentamer interfaces. Definition of the ligand-binding pocket and the gating C-loop in the 6 Å structure suggests that 3D-EM might lead to the identification of functional states in the BgAChBP dodecahedron. PMID:22916297

Kapetanopoulos, Katharina; Braukmann, Sandra; Gebauer, Wolfgang; Tenzer, Stefan; Markl, Jürgen

2012-01-01

48

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

PubMed

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

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

2006-09-01

49

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

50

A family of variable immunoglobulin and lectin domain containing molecules in the snail Biomphalaria glabrata.  

PubMed

Technical limitations have hindered comprehensive studies of highly variable immune response molecules that are thought to have evolved due to pathogen-mediated selection such as fibrinogen-related proteins (FREPs) from Biomphalaria glabrata. FREPs combine upstream immunoglobulin superfamily (IgSF) domains with a C-terminal fibrinogen-related domain (FreD) and participate in reactions against trematode parasites. From RNAseq data we assembled a de novo reference transcriptome of B. glabrata to investigate the diversity of FREP transcripts. This study increased over two fold the number of bonafide FREP subfamilies and revealed important sequence diversity within FREP12 subfamily. We also report the discovery of related molecules that feature one or two IgSF domains associated with different C-terminal lectin domains, named C-type lectin-related proteins (CREPs) and Galectin-related protein (GREP). Together, the highly similar FREPs, CREPs and GREP were designated VIgL (Variable Immunoglobulin and Lectin domain containing molecules). PMID:25451302

Dheilly, Nolwenn M; Duval, David; Mouahid, Gabriel; Emans, Rémi; Allienne, Jean-François; Galinier, Richard; Genthon, Clémence; Dubois, Emeric; Du Pasquier, Louis; Adema, Coen M; Grunau, Christoph; Mitta, Guillaume; Gourbal, Benjamin

2015-01-01

51

Impact of certain plants and synthetic molluscicides on some fresh water snails and fish.  

PubMed

The LC50 (78, 85 ppm) and LC90 (88, 135 ppm) of Anagalis arvensis and Calendula micrantha respectively against Biomphalaria alexandrina were higher than those of the non-target snails, Physa acuta, Planorbis planorbis, Helisoma duryi and Melanoides tuberculata. In contrast, the LC50 of Niclosamide (0.11 ppm) and Copper sulphate (CuSO4) (0.42 ppm) against B. alexandrina were lower than those of the non-target snails. The mortalities percentage among non-target snails ranged between 0.0 & 20% when sublethal concentrations of CuSO4 against B. alexandrina mixed with those of C. micrantha and between 0.0 & 40% when mixed with A. arvensis. Mortalities ranged between 0.0 & 50% when Niclosamide was mixed with each of A. arvensis and C. micrantha. A. arvensis induced 100% mortality on Oreochromis niloticus after 48 hrs exposure and after 24 hrs for Gambusia affinis. C. micrantha was non-toxic to the fish. The survival rate of O. niloticus and G. affinis after 48 hrs exposure to 0.11 ppm of Niclosamide were 83.3% & 100% respectively. These rates were 91.7% & 93.3% respectively when each of the two fish species was exposed to 0.42 ppm of CuSO4. Mixture of sub-lethal concentrations of A. arvensis against B. alexandrina and those of Niclosamide or CuSO4 at ratios 10:40 & 25:25 induced 66.6% mortalities on O. niloticus and 83.3% at 40:10. These mixtures caused 100% mortalities on G. affinis at all ratios. A. arvensis CuSO4 mixtures at 10:40 induced 83.3% & 40% mortalities on O. niloticus and G. affinis respectively and 100% mortalities on both fish species at ratios 25:25 & 40:10. A mixture of sub-lethal concentrations of C. micrantha against B. alexandrina and of Niclosamide or CuSO4 caused mortalities of O. niloticus between 0.0 & 33.3% and between 5% & 35% of G. affinis. The residue of Cu in O. niloticus were 4.69, 19.06 & 25.37 mg/1kgm fish after 24, 48 & 72 hrs exposure to LC0 of CuSO4 against B. alexandrina respectively. PMID:16333905

Mosta-Fa, B B; el-Deeb, Fatma A; Ismail, Nahid M; el-Said, K M

2005-12-01

52

UDP-N-acetyl-?-D-galactosamine:polypeptide N-acetylgalactosaminyl-transferase from the snail Biomphalaria glabrata - substrate specificity and preference of glycosylation sites.  

PubMed

O-glycosylation is a widely occurring posttranslational modification of proteins. The glycosylation status of a specific site may influence the location, activity and function of a protein. The initiating enzyme of mucin-type O-glycosylation is UDP-GalNAc:polypeptide GalNAc transferase (ppGalNAcT; EC 2.4.1.41). Using electron-transfer dissociation mass spectrometry, ppGalNAcT from the snail Biomphalaria glabrata was characterized regarding its ability to glycosylate threonine and serine residues in different peptide sequence environments. The preferences of the snail enzyme for flanking amino acids of the potential glycosylation site were very similar to vertebrate and insect members of the family. Acceptor sites with adjacent proline residues were highly preferred, while other residues caused less pronounced effects. No specific O-glycosylation consensus sequence was found. The results obtained from synthetic peptides were in good correlation with the observed glycosylation patterns of native peptides and with the order of attachment in a multi-glycosylated peptide. The snail enzyme clearly preferred threonine over serine in the in vitro assays. No significant differences of transfer speed or efficiency could be detected using a mutant of the enzyme lacking the lectin domain. This is the first characterisation of the substrate specificity of a member of the ppGalNAcT family from mollusc origin. PMID:25338825

Taus, Christopher; Windwarder, Markus; Altmann, Friedrich; Grabherr, Reingard; Staudacher, Erika

2014-12-01

53

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

Microsoft Academic Search

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

Verónica Flores; Norma Brugni

2005-01-01

54

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

PubMed Central

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

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

2008-01-01

55

Characterization of immune genes from the schistosome host snail Biomphalaria glabrata that encode peptidoglycan recognition proteins and gram-negative bacteria binding protein  

PubMed Central

Peptidoglycan (PGN) recognition proteins (PGRPs) and gram-negative bacteria binding proteins (GNBPs) play an essential role in Toll/Imd signaling pathways in arthropods. The existence of homologous pathways involving PGRPs and GNBPs in other major invertebrate phyla such as the Mollusca remains unclear. In this paper, we report four full-length PGRP cDNAs and one full-length GNBP cDNA cloned from the snail Biomphalaria glabrata, the intermediate host of the human blood fluke Schistosoma mansoni, designated as BgPGRPs and BgGNBP, respectively. Three transcripts are generated from a long form PGRP gene (BgPGRP-LA) by alternative splicing and one from a short form PGRP gene (BgPGRP-SA). BgGNBP encodes a putative secreted protein. Northern blots demonstrated that expression of BgPGRP-SA and BgGNBP was down-regulated in B. glabrata at 6 h after exposure to three types of microbes. No significant changes in expression were observed in snails at 2 days post-exposure (dpe) to the trematodes Echinostoma paraensei or S. mansoni. However, up-regulation of BgPGRP-SA in M line snails at later time points of infection with E. paraensei (i.e., 12 and 17 dpe) was observed. Our study revealed that exposure to either microbes or trematodes did not alter the expression levels of BgPGRP-LAs, which were consistently low. This study provides new insights into the potential pathogen recognition capabilities of molluscs, indicates that further studies of the Toll/Imd pathways in this phylum are in order, and provides additional ways to judge the importance of this pathway in the evolution of internal defense across the animal phyla. PMID:17805526

Zeng, Yong; Loker, Eric S.

2013-01-01

56

Update of fasciolosis-transmitting snails in Egypt (review and comment).  

PubMed

Several snail species may contribute in transmission of fasciolosis in Egypt. These molluscs show a variable sensibility to natural infections with Fasciola species. Radix natalensis is considered to be the essential intermediate host for F. gigantica based on field and experimental studies. Cercarial production from R. natalensis experimentally infected with F. gigantica is affected by the species of definitive host from which the eggs are obtained, as well as the different laboratory conditions. Another lymnaeid, Galba truncatula, may play a role in transmitting this parasite in Egypt, as it was found naturally infected with F. gigantica. Latter snail species, originated from France, was susceptible to experimental infections with Egyptian miracidia of F. gigantica and it had a cercarial production close to that of local R. natalensis. Two other snails, Pseudosuccinea columella and Biomphalaria alexandrina, were naturally found harboring larvae of Fasciola sp. At the level of intermediate hosts of F. gigantica, the conditions are thus favorable in Egypt to transmit fasciolosis which could also be caused by another fasciolid, F. hepatica, as the existance of this fluke was confirmed in Egypt. PMID:16083061

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

2005-08-01

57

Effect of Agave attenuata extracts on detoxification enzymes of Biomphlaria alexandrina  

Microsoft Academic Search

The toxicity and rising costs of synthetic molluscicides have led to interest in compounds derived from locally growing plants\\u000a that can be used as molluscicides. The aim of the present work was to study the effect of extracts of some Egyptian plants\\u000a having lethal effect on snails of medical importance (Biomphlaria alexandrina) as well as on antioxidant and glutathione detoxification

R. R. Hamed; T. M. Maharem; N. M. Farid; Kh. Ramadan; M. H. Abdel Aziz

2006-01-01

58

INTRODUCTION Embryos of the freshwater common pond snail Lymnaea stagnalis  

E-print Network

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

Grosell, Martin

59

5-methyl-cytosine and 5-hydroxy-methyl-cytosine in the genome of Biomphalaria glabrata, a snail intermediate host of Schistosoma mansoni  

PubMed Central

Background Biomphalaria glabrata is the mollusc intermediate host for Schistosoma mansoni, a digenean flatworm parasite that causes human intestinal schistosomiasis. An estimated 200 million people in 74 countries suffer from schistosomiasis, in terms of morbidity this is the most severe tropical disease after malaria. Epigenetic information informs on the status of gene activity that is heritable, for which changes are reversible and that is not based on the DNA sequence. Epigenetic mechanisms generate variability that provides a source for potentially heritable phenotypic variation and therefore could be involved in the adaptation to environmental constraint. Phenotypic variations are particularly important in host-parasite interactions in which both selective pressure and rate of evolution are high. In this context, epigenetic changes are expected to be major drivers of phenotypic plasticity and co-adaptation between host and parasite. Consequently, with characterization of the genomes of invertebrates that are parasite vectors or intermediate hosts, it is also essential to understand how the epigenetic machinery functions to better decipher the interplay between host and parasite. Methods The CpGo/e ratios were used as a proxy to investigate the occurrence of CpG methylation in B. glabrata coding regions. The presence of DNA methylation in B. glabrata was also confirmed by several experimental approaches: restriction enzymatic digestion with isoschizomers, bisulfite conversion based techniques and LC-MS/MS analysis. Results In this work, we report that DNA methylation, which is one of the carriers of epigenetic information, occurs in B. glabrata; approximately 2% of cytosine nucleotides are methylated. We describe the methylation machinery of B. glabrata. Methylation occurs predominantly at CpG sites, present at high ratios in coding regions of genes associated with housekeeping functions. We also demonstrate by bisulfite treatment that methylation occurs in multiple copies of Nimbus, a transposable element. Conclusions This study details DNA methylation for the first time, one of the carriers of epigenetic information in B. glabrata. The general characteristics of DNA methylation that we observed in the B. glabrata genome conform to what epigenetic studies have reported from other invertebrate species. PMID:23742053

2013-01-01

60

Compatibility of Biomphalaria tenagophila with Schistosoma mansoni: a study of homologous plasma transference.  

PubMed

This study aims to investigate the importance of the serum factors present in the plasma of resistant Biomphalaria tenagophila snails, when transferred to susceptible conspecific. Susceptible B. tenagophila (CF) received plasma from resistant B. tenagophila (Taim), and both were later infected with Schistosoma mansoni. We noticed that the plasma transfer showed an increase on the resistance of susceptible snails of about 86% when compared to the non-immunized group (p < 0.001). PMID:16699720

Coelho, João R; Bezerra, Fernando S M

2006-02-01

61

Biomphalaria glabrata peroxiredoxin: Effect of Schistosoma mansoni infection on differential gene regulation  

Microsoft Academic Search

To identify gene(s) that may be associated with resistance\\/susceptibility in the intermediate snail host Biomphalaria glabrata to Schistosoma mansoni infection, a snail albumen gland cDNA library was differentially screened and a partial cDNA encoding an antioxidant enzyme thioredoxin peroxidase (Tpx), or peroxiredoxin (Prx), was identified. The 753bp full-length, single-copy, constitutively expressed gene now referred to as BgPrx4 was later isolated.

Matty Knight; Nithya Raghavan; Cheri Goodall; Carolyn Cousin; Wannaporn Ittiprasert; Ahmed Sayed; Andre Miller; David L. Williams; Christopher J. Bayne

2009-01-01

62

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

63

Schistosoma mansoni and Biomphalaria: past history and future trends.  

PubMed

Schistosoma mansoni is one of the most abundant infectious agents of humankind. Its widespread distribution is permitted by the broad geographic range of susceptible species of the freshwater snail genus Biomphalaria that serve as obligatory hosts for its larval stages. Molecular phylogenetic studies suggest that Schistosoma originated in Asia, and that a pulmonate-transmitted progenitor colonized Africa and gave rise to both terminal-spined and lateral-spined egg species groups, the latter containing S. mansoni. Schistosoma mansoni likely appeared only after the trans-Atlantic dispersal of Biomphalaria from the Neotropics to Africa, an event that, based on the present African fossil record, occurred only 2-5 million years ago. This parasite became abundant in tropical Africa and then entered the New World with the slave trade. It prospered in the Neotropics because a remarkably susceptible and productive host, B. glabrata, was widely distributed there. Indeed, a snail similar to B. glabrata may have given rise to the African species of Biomphalaria. Schistosoma mansoni has since spread into other Neotropical Biomphalaria species and mammalian hosts. The distribution of S. mansoni is in a state of flux. In Egypt, S. mansoni has nearly completely replaced S. haematobium in the Nile Delta, and has spread to other regions of the country. A susceptible host snail, B. straminea, has been introduced into Asia and there is evidence of S. mansoni transmission in Nepal. Dam and barrage construction has lead to an epidemic of S. mansoni in Senegal, and the parasite continues its spread in Brazil. Because of competition with introduced aquatic species and environmental changes, B. glabrata and consequently S. mansoni have become less abundant on the Caribbean islands. Control of S. mansoni using praziquantel and oxamniquine has reduced global prevalence but control is difficult to sustain, and S. mansoni can develop tolerance/resistance to praziquantel, raising concerns about its future efficacy. Because of legitimate environmental concerns, snail control is unlikely to be an option in future control efforts. Global warming will impact the distribution of Biomphalaria and S. mansoni, but the magnitude and nature of the effects are poorly understood. PMID:11769285

Morgan, J A; Dejong, R J; Snyder, S D; Mkoji, G M; Loker, E S

2001-01-01

64

The population genetic structure of Biomphalaria choanomphala in Lake Victoria, East Africa: implications for schistosomiasis transmission.  

PubMed

BackgroundThe freshwater snail Biomphalaria acts as the intermediate host of Schistosoma mansoni, a globally important human parasite. Understanding the population structure of intermediate host species can elucidate transmission dynamics and assist in developing appropriate control methods.MethodsWe examined levels of population genetic structure and diversity in 29 populations of Biomphalaria choanomphala collected around the shoreline of Lake Victoria in Uganda, Kenya and Tanzania, where S. mansoni is hyper-endemic. Molecular markers were utilized to estimate the degree to which snail populations are genetically differentiated from one another.ResultsHigh levels of snail genetic diversity were found coupled with evidence of geographically-determined population structure but low levels of local inbreeding. The data are consistent with an effect of schistosome infection on population structure of intermediate host snails, but other factors, such as habitat and historical demographic changes, could also be important determinants of the degree of population genetic structure in Biomphalaria choanomphala.ConclusionsThe low stratification of populations and high genetic diversity indicates potentially less local compatibility with intermediate snail populations than previously theorized, and highlights the importance of coordinated parasite control strategies across the region. PMID:25406437

Standley, Claire J; Goodacre, Sara L; Wade, Christopher M; Stothard, J

2014-11-19

65

Update on the distribution and phylogenetics of Biomphalaria (Gastropoda: Planorbidae) populations in Guangdong Province, China.  

PubMed

In 1973 planorbid snails then identified as Biomphalaria straminea were discovered in Hong Kong, China. It was assumed that these snails had been introduced to Hong Kong via the import of tropical fish by air from South America. In 2012 Biomphalaria were found for the first time in Guangdong Province, China. In view of the renewed interest in these invasive snails, a morphological and DNA-sequence based phylogenetic study was undertaken for seven populations of Biomphalaria snails collected in Guangdong. Morphologically and phylogenetically, five of the populations clustered more closely with Biomphalaria kuhniana than with B. straminea. Levels of genetic diversity among the populations were about half those of autochthonous populations in Brazil, the phylogenetic relationships did not correlate with a radiation from any one international port in China, and different lineages appeared associated with different ports. Consequently in explaining the current distribution of the snails, multiple colonization events, each establishing a new local snail population near to maritime international container ports, were considered more likely than the spread of snails from Hong Kong to China. The displacement of B. straminea by B. kuhniana in Guangdong is considered as an explanation for the habitat changes observed among the snails between Hong Kong in the 1980s and the present. The conclusions of the study are that any risk of Schistosoma mansoni transmission in China is more likely to come from parasite importation in the intramolluscan stage, than from transmission by migrant workers from South America or Africa. In addition, although likely to be rare, sporadic outbreaks of imported schistosomiasis (caused by invading infected snails) could be a threat to public health in the vicinity of International container ports (not only in Guangdong Province). Further work is called for to investigate further the presence of B. kuhniana and its potential interactions with B. straminea (the former is thought to be incompatible with S. mansoni), and the responses of Chinese Biomphalaria to potential competitors such as Thiaridae. The current expansion of container ports in Brazil and Venezuela, and the increase in trade with China, is likely to accentuate any current risk of imported schistosomiasis, and surveillance around ports in China, together with further research, are necessary. PMID:24811366

Attwood, Stephen W; Huo, Guan-Nan; Qiu, Jian-Wen

2015-01-01

66

[Molluscicide activity of some natural products on Biomphalaria glabrata].  

PubMed

The molluscicide activity of aqueous (macerated and boiled), hexanic and ethylic extracts of Aristolochia brasiliensis, Caesalpinia peltophoroides, Caesalpinia pulcherrima, Delonix regia, Spathodea campanulata and Tibouchina scrobiculata was evaluated in the laboratory. The solutions obtained from those extracts were tested on adults and egg masses of Biomphalaria glabrata reared in the laboratory at 1, 10, 20, 100 and 1000 ppm concentrations. The most active of the extracts studied was D. regia flowers' (flamboyant) ethylic extracts which presented molluscicidal activity on adult snails at 20 ppm. PMID:3796282

Mendes, N M; de Souza, C P; Araújo, N; Pereira, J P; Katz, N

1986-01-01

67

A Novel Bacterial Pathogen of Biomphalaria glabrata: A Potential Weapon for Schistosomiasis Control?  

PubMed Central

Background Schistosomiasis is the second-most widespread tropical parasitic disease after malaria. Various research strategies and treatment programs for achieving the objective of eradicating schistosomiasis within a decade have been recommended and supported by the World Health Organization. One of these approaches is based on the control of snail vectors in endemic areas. Previous field studies have shown that competitor or predator introduction can reduce snail numbers, but no systematic investigation has ever been conducted to identify snail microbial pathogens and evaluate their molluscicidal effects. Methodology/Principal findings In populations of Biomphalaria glabrata snails experiencing high mortalities, white nodules were visible on snail bodies. Infectious agents were isolated from such nodules. Only one type of bacteria, identified as a new species of Paenibacillus named Candidatus Paenibacillus glabratella, was found, and was shown to be closely related to P. alvei through 16S and Rpob DNA analysis. Histopathological examination showed extensive bacterial infiltration leading to overall tissue disorganization. Exposure of healthy snails to Paenibacillus-infected snails caused massive mortality. Moreover, eggs laid by infected snails were also infected, decreasing hatching but without apparent effects on spawning. Embryonic lethality was correlated with the presence of pathogenic bacteria in eggs. Conclusions/Significance This is the first account of a novel Paenibacillus strain, Ca. Paenibacillus glabratella, as a snail microbial pathogen. Since this strain affects both adult and embryonic stages and causes significant mortality, it may hold promise as a biocontrol agent to limit schistosomiasis transmission in the field. PMID:25719489

Duval, David; Galinier, Richard; Mouahid, Gabriel; Toulza, Eve; Allienne, Jean François; Portela, Julien; Calvayrac, Christophe; Rognon, Anne; Arancibia, Nathalie; Mitta, Guillaume; Théron, André; Gourbal, Benjamin

2015-01-01

68

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

69

Malacological survey and geographical distribution of vector snails for schistosomiasis within informal settlements of Kisumu City, western Kenya  

PubMed Central

Background Although schistosomiasis is generally considered a rural phenomenon, infections have been reported within urban settings. Based on observations of high prevalence of Schistosoma mansoni infection in schools within the informal settlements of Kisumu City, a follow-up malacological survey incorporating 81 sites within 6 informal settlements of the City was conducted to determine the presence of intermediate host snails and ascertain whether active transmission was occurring within these areas. Methods Surveyed sites were mapped using a geographical information system. Cercaria shedding was determined from snails and species of snails identified based on shell morphology. Vegetation cover and presence of algal mass at the sites was recorded, and the physico-chemical characteristics of the water including pH and temperature were determined using a pH meter with a glass electrode and a temperature probe. Results Out of 1,059 snails collected, 407 (38.4%) were putatively identified as Biomphalaria sudanica, 425 (40.1%) as Biomphalaria pfeifferi and 227 (21.5%) as Bulinus globosus. The spatial distribution of snails was clustered, with few sites accounting for most of the snails. The highest snail abundance was recorded in Nyamasaria (543 snails) followed by Nyalenda B (313 snails). As expected, the mean snail abundance was higher along the lakeshore (18 ± 12 snails) compared to inland sites (dams, rivers and springs) (11 ± 32 snails) (F1, 79 = 38.8, P < 0.0001). Overall, 19 (1.8%) of the snails collected shed schistosome cercariae. Interestingly, the proportion of infected Biomphalaria snails was higher in the inland (2.7%) compared to the lakeshore sites (0.3%) (P = 0.0109). B. sudanica was more abundant in sites along the lakeshore whereas B. pfeifferi and B. globosus were more abundant in the inland sites. Biomphalaria and Bulinus snails were found at 16 and 11 out of the 56 inland sites, respectively. Conclusions The high abundance of Biomphalaria and Bulinus spp. as well as observation of field-caught snails shedding cercariae confirmed that besides Lake Victoria, the local risk for schistosomiasis transmission exists within the informal settlements of Kisumu City. Prospective control interventions in these areas need to incorporate focal snail control to complement chemotherapy in reducing transmission. PMID:22152486

2011-01-01

70

Lethal and Sub-lethal Effects of UVB on Juvenile Biomphalaria glabrata (Mollusca: Pulmonata)  

PubMed Central

Although Schistosoma mansoni occurs mainly in the tropics, where intense levels of solar radiation are present, the impact of ultraviolet (UV) light on schistosome transmission is not known. The purpose of this study was to investigate potential effects of UVB (290–320 nm) on juvenile Biomphalaria glabrata, the snail intermediate host of S. mansoni. Albino and wild type snails were exposed to doses of UVB from UV-fluorescent lamps, and the following were measured: survival, photoreactivation (light-mediated DNA repair), effects on feeding behavior, and morphological tissue abnormalities. Irradiation with UVB is lethal to B. glabrata in a dose-dependent manner. Exposure to white light subsequent to UVB irradiation enhances survival, probably by photoreactivation. The shell offers some, but not complete, protection. Experiments in which UVB transmittance through the shell was blocked with black nail polish suggest that injury to both exposed (headfoot) and shell-enclosed (mantle and visceral mass) tissues contributes to mortality in lethally-irradiated snails. Wild-type (pigmented) snails are less susceptible to lethal effects of UVB than albino snails, and they may be more capable of photoreactivation. UVB exposure inhibits snail feeding behavior, and causes tentacle forks and growths on the headfoot. Thus, UVB may influence the life cycle of S. mansoni by both lethal and sub-lethal damage to the snail intermediate host. However, the ability of snails to photoreactivate may mitigate these effects. PMID:16996081

Ruelas, Debbie S.; Karentz, Deneb; Sullivan, John T.

2007-01-01

71

Biomphalaria glabrata peroxiredoxin: effect of Schistosoma mansoni infection on differential gene regulation  

PubMed Central

To identify gene(s) that may be associated with resistance/susceptibility in the intermediate snail host Biomphalaria glabrata to Schistosoma mansoni infection, a snail albumen gland cDNA library was differentially screened and a partial cDNA encoding an antioxidant enzyme thioredoxin peroxidase (Tpx), or peroxiredoxin (Prx), was identified. The 753 bp full-length, single-copy, constitutively expressed gene now referred to as BgPrx4 was later isolated. BgPrx4 is a 2-Cys peroxiredoxin containing the conserved peroxidatic cysteine (CP) in the N-terminus and the resolving cysteine (CR) in the C-terminus. Sequence analysis of BgPrx4 from both resistant and susceptible snails revealed the presence of several (at least 7) Single Nucleotide Polymorphisms (SNPs). Phylogenetic analysis indicated BgPrx4 to resemble a homolog of human peroxiredoxin, PRDX4. Northern analysis of hepatopancreas RNA from both resistant and susceptible snails showed that upon parasite exposure there were qualitative changes in gene expression. Quantitative real-time RT-PCR analysis showed differences in the levels of BgPrx4 transcript induction following infection, with the transcript up-regulated in resistant snails during the early phase (5 h) of infection compared to susceptible snails in which it was down-regulated within the early time period. While there was an increase in transcription in susceptible snails later (48 h) post- infection, this never reached the levels detected in resistant snails. A similar trend - higher, earlier up-regulation in the resistant snails but lower, slower protein expression in susceptible snails - was observed by Western blot analysis. Enzymatic analysis of the purified, recombinant BgPrx4 revealed the snail sequence to function as Prx but with an unusual ability to use both thioredoxin and glutathione as substrates. PMID:19439374

Knight, Matty; Raghavan, Nithya; Goodall, Cheri; Cousin, Carolyn; Ittiprasert, Wannaporn; Sayed, Ahmed; Miller, Andre; Williams, David L; Bayne, Christopher J

2009-01-01

72

Environmental Epidemiology of Intestinal Schistosomiasis in Uganda: Population Dynamics of Biomphalaria (Gastropoda: Planorbidae) in Lake Albert and Lake Victoria with Observations on Natural Infections with Digenetic Trematodes  

PubMed Central

This study documented the population dynamics of Biomphalaria and associated natural infections with digenetic trematodes, along the shores of Lake Albert and Lake Victoria, recording local physicochemical factors. Over a two-and-a-half-year study period with monthly sampling, physicochemical factors were measured at 12 survey sites and all freshwater snails were collected. Retained Biomphalaria were subsequently monitored in laboratory aquaria for shedding trematode cercariae, which were classified as either human infective (Schistosoma mansoni) or nonhuman infective. The population dynamics of Biomphalaria differed by location and by lake and had positive relationship with pH (P < 0.001) in both lakes and negative relationship with conductivity (P = 0.04) in Lake Albert. Of the Biomphalaria collected in Lake Albert (N = 6,183), 8.9% were infected with digenetic trematodes of which 15.8% were shedding S. mansoni cercariae and 84.2% with nonhuman infective cercariae. In Lake Victoria, 2.1% of collected Biomphalaria??(N = 13,172) were infected with digenetic trematodes with 13.9% shedding S. mansoni cercariae, 85.7% shedding nonhuman infective cercariae, and 0.4% of infected snails shedding both types of cercariae. Upon morphological identification, species of Biomphalaria infected included B. sudanica, B. pfeifferi, and B. stanleyi in Lake Albert and B. sudanica, B. pfeifferi, and B. choanomphala in Lake Victoria. The study found the physicochemical factors that influenced Biomphalaria population and infections. The number and extent of snails shedding S. mansoni cercariae illustrate the high risk of transmission within these lake settings. For better control of this disease, greater effort should be placed on reducing environmental contamination by improvement of local water sanitation and hygiene. PMID:25705680

Rowel, Candia; Fred, Besigye; Sousa-Figueiredo, Jose C.; Kabatereine, Narcis B.; Stothard, J. Russell

2015-01-01

73

Environmental epidemiology of intestinal schistosomiasis in Uganda: population dynamics of biomphalaria (gastropoda: planorbidae) in lake albert and lake victoria with observations on natural infections with digenetic trematodes.  

PubMed

This study documented the population dynamics of Biomphalaria and associated natural infections with digenetic trematodes, along the shores of Lake Albert and Lake Victoria, recording local physicochemical factors. Over a two-and-a-half-year study period with monthly sampling, physicochemical factors were measured at 12 survey sites and all freshwater snails were collected. Retained Biomphalaria were subsequently monitored in laboratory aquaria for shedding trematode cercariae, which were classified as either human infective (Schistosoma mansoni) or nonhuman infective. The population dynamics of Biomphalaria differed by location and by lake and had positive relationship with pH (P < 0.001) in both lakes and negative relationship with conductivity (P = 0.04) in Lake Albert. Of the Biomphalaria collected in Lake Albert (N = 6,183), 8.9% were infected with digenetic trematodes of which 15.8% were shedding S. mansoni cercariae and 84.2% with nonhuman infective cercariae. In Lake Victoria, 2.1% of collected Biomphalaria??(N = 13,172) were infected with digenetic trematodes with 13.9% shedding S. mansoni cercariae, 85.7% shedding nonhuman infective cercariae, and 0.4% of infected snails shedding both types of cercariae. Upon morphological identification, species of Biomphalaria infected included B. sudanica, B. pfeifferi, and B. stanleyi in Lake Albert and B. sudanica, B. pfeifferi, and B. choanomphala in Lake Victoria. The study found the physicochemical factors that influenced Biomphalaria population and infections. The number and extent of snails shedding S. mansoni cercariae illustrate the high risk of transmission within these lake settings. For better control of this disease, greater effort should be placed on reducing environmental contamination by improvement of local water sanitation and hygiene. PMID:25705680

Rowel, Candia; Fred, Besigye; Betson, Martha; Sousa-Figueiredo, Jose C; Kabatereine, Narcis B; Stothard, J Russell

2015-01-01

74

Schistosomes and snails: a molecular encounter  

PubMed Central

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

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

2014-01-01

75

Snails home  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

76

Snail Shell  

USGS Multimedia Gallery

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

77

Early Differential Gene Expression in Haemocytes from Resistant and Susceptible Biomphalaria glabrata Strains in Response to Schistosoma mansoni  

PubMed Central

The outcome of infection in the host snail Biomphalaria glabrata with the digenean parasite Schistosoma mansoni is determined by the initial molecular interplay occurring between them. The mechanisms by which schistosomes evade snail immune recognition to ensure survival are not fully understood, but one possibility is that the snail internal defence system is manipulated by the schistosome enabling the parasite to establish infection. This study provides novel insights into the nature of schistosome resistance and susceptibility in B. glabrata at the transcriptomic level by simultaneously comparing gene expression in haemocytes from parasite-exposed and control groups of both schistosome-resistant and schistosome-susceptible strains, 2 h post exposure to S. mansoni miracidia, using an novel 5K cDNA microarray. Differences in gene expression, including those for immune/stress response, signal transduction and matrix/adhesion genes were identified between the two snail strains and tests for asymmetric distributions of gene function also identified immune-related gene expression in resistant snails, but not in susceptible. Gene set enrichment analysis revealed that genes involved in mitochondrial electron transport, ubiquinone biosynthesis and electron carrier activity were consistently up-regulated in resistant snails but down-regulated in susceptible. This supports the hypothesis that schistosome-resistant snails recognize schistosomes and mount an appropriate defence response, while in schistosome-susceptible snails the parasite suppresses this defence response, early in infection. PMID:23300533

Lockyer, Anne E.; Emery, Aidan M.; Kane, Richard A.; Walker, Anthony J.; Mayer, Claus D.; Mitta, Guillaume; Coustau, Christine; Adema, Coen M.; Hanelt, Ben; Rollinson, David; Noble, Leslie R.; Jones, Catherine S.

2012-01-01

78

Early differential gene expression in haemocytes from resistant and susceptible Biomphalaria glabrata strains in response to Schistosoma mansoni.  

PubMed

The outcome of infection in the host snail Biomphalaria glabrata with the digenean parasite Schistosoma mansoni is determined by the initial molecular interplay occurring between them. The mechanisms by which schistosomes evade snail immune recognition to ensure survival are not fully understood, but one possibility is that the snail internal defence system is manipulated by the schistosome enabling the parasite to establish infection. This study provides novel insights into the nature of schistosome resistance and susceptibility in B. glabrata at the transcriptomic level by simultaneously comparing gene expression in haemocytes from parasite-exposed and control groups of both schistosome-resistant and schistosome-susceptible strains, 2 h post exposure to S. mansoni miracidia, using an novel 5K cDNA microarray. Differences in gene expression, including those for immune/stress response, signal transduction and matrix/adhesion genes were identified between the two snail strains and tests for asymmetric distributions of gene function also identified immune-related gene expression in resistant snails, but not in susceptible. Gene set enrichment analysis revealed that genes involved in mitochondrial electron transport, ubiquinone biosynthesis and electron carrier activity were consistently up-regulated in resistant snails but down-regulated in susceptible. This supports the hypothesis that schistosome-resistant snails recognize schistosomes and mount an appropriate defence response, while in schistosome-susceptible snails the parasite suppresses this defence response, early in infection. PMID:23300533

Lockyer, Anne E; Emery, Aidan M; Kane, Richard A; Walker, Anthony J; Mayer, Claus D; Mitta, Guillaume; Coustau, Christine; Adema, Coen M; Hanelt, Ben; Rollinson, David; Noble, Leslie R; Jones, Catherine S

2012-01-01

79

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

PubMed

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

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

2008-08-01

80

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

E-print Network

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

Dillon, Robert T.

81

Physiological changes and molluscicidal effects of crude latex and Milin on Biomphalaria glabrata.  

PubMed

Euphorbian latex is commonly used as molluscicides and the Euphorbia milii latex was reported as most powerful molluscicidal agents. The physiological and lethal effects of the latex components of Euphorbia milii, on the intermediate host Biomphalaria spp., of the human liver parasite Schistosoma mansoni were described in this study. The standard methodologies for testing plant derived molluscicides formulated by World Health Organisation (WHO) were followed with some modifications. The young specimen of fresh water snails showed altered physiological and physical response towards latex components. The working concentration of non-proteinaceous fraction (up to 0.1%) of the latex reduced the active physiological behaviour but was non-lethal to young specimen of snails. However, proteinaceous fractions (0.1mg/l) of the latex were found lethal to snail population, and lethality was enhanced with small amount of the non-proteinaceous fraction (0.01%) of the latex. Milin, a serine protease(up to 0.1mg/l), isolated from the latex of Euphorbia milii significantly reduced the growth and feeding activity but was not lethal to young specimen of snails. With an addition of 0.01% of non-proteinaceous fractions to Milin, lethality result was similar to that of crude latex. Milin is likely to be responsible for alteration of normal physiological functions and lethality of snails, thus it may be used as a molluscicide to control transmission of the endemic disease schistosomiasis. PMID:18262588

Yadav, Subhash C; Jagannadham, M V

2008-04-01

82

Bibliotheca Alexandrina--Reviving a Legacy of the Past for a Brighter Common Future.  

ERIC Educational Resources Information Center

Discusses the ancient library at Alexandria and describes plans for the development of the new Bibliotheca Alexandrina. The administrative organization is discussed; the building design is explained; international cooperation between Egypt, UNESCO, UNDP (United Nations Development Programme), and the library community is described; and future…

Tocatlian, Jacques

1991-01-01

83

Susceptibility and compatibility of Biomphalaria tenagophila from the Río de la Plata basin with Schistosoma mansoni from Brazil.  

PubMed

Schistosomiasis has expanded to southern parts of Brazil. Between 2005-2007 the dispersion and the proliferation of Biomphalaria tenagophila was verified in the province of Corrientes near the Brazilian border. In order to study the possibility that schistosomiasis might spread into the basins of the Paraná and Uruguay Rivers, 440 B. tenagophila collected from 10 populations groups were experimentally exposed to infection with Schistosoma mansoni of the SJ2 strain. Snails from five localities were susceptible. Frandsen's index (TCP/100) shows that those snails from Mirungá (11%), Aguacerito (2%) and Curupicay (2%) were Class I and not very compatible. Meanwhile, snails from Copra (6%) and Pay-Ubre (22%), in the Paraná River basin, were Class II and poorly compatible. PMID:20721498

Borda, Carlos Edgardo; Rea, María Josefa F

2010-07-01

84

Differences in the Gene Expression Profiles of Haemocytes from Schistosome-Susceptible and -Resistant Biomphalaria glabrata Exposed to Schistosoma mansoni Excretory-Secretory Products  

PubMed Central

During its life cycle, the helminth parasite Schistosoma mansoni uses the freshwater snail Biomphalaria glabrata as an intermediate host to reproduce asexually generating cercariae for infection of the human definitive host. Following invasion of the snail, the parasite develops from a miracidium to a mother sporocyst and releases excretory-secretory products (ESPs) that likely influence the outcome of host infection. To better understand molecular interactions between these ESPs and the host snail defence system, we determined gene expression profiles of haemocytes from S. mansoni-resistant or -susceptible strains of B. glabrata exposed in vitro to S. mansoni ESPs (20 ?g/ml) for 1 h, using a 5K B. glabrata cDNA microarray. Ninety-eight genes were found differentially expressed between haemocytes from the two snail strains, 57 resistant specific and 41 susceptible specific, 60 of which had no known homologue in GenBank. Known differentially expressed resistant-snail genes included the nuclear factor kappa B subunit Relish, elongation factor 1?, 40S ribosomal protein S9, and matrilin; known susceptible-snail specific genes included cathepsins D and L, and theromacin. Comparative analysis with other gene expression studies revealed 38 of the 98 identified genes to be uniquely differentially expressed in haemocytes in the presence of ESPs, thus identifying for the first time schistosome ESPs as important molecules that influence global snail host-defence cell gene expression profiles. Such immunomodulation may benefit the schistosome, enabling its survival and successful development in the snail host. PMID:24663063

Davies, Angela J.; Kirk, Ruth S.; Emery, Aidan M.; Rollinson, David; Jones, Catherine S.; Noble, Leslie R.; Walker, Anthony J.

2014-01-01

85

Screening for novel plant sources of prenyloxyanthraquinones: Senna alexandrina Mill. and Aloe vera (L.) Burm. F.  

PubMed

As a continuation of our ongoing studies aimed to reveal the presence of oxyprenylated anthraquinones in plants claimed to have a laxative effect, in this article, we describe the extraction and HPLC separation of madagascin (3-isopentenyloxyemodin) and 3-geranyloxyemodine from dried leaves and fruits of Senna alexandrina Mill. (Leguminosae) and leaves and gel of Aloe vera (L.) Burm. F. (Xanthorrhoeaceae). Both compounds are described herein for the first time as components of extracts of the title plants. PMID:25342202

Epifano, Francesco; Fiorito, Serena; Locatelli, Marcello; Taddeo, Vito Alessandro; Genovese, Salvatore

2015-01-01

86

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

PubMed

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

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

2013-10-01

87

The susceptibility of Biomphalaria glabrata throughout its life-history to N-tritylmorpholine  

PubMed Central

This study was undertaken as part of a detailed investigation of the molluscicidal properties of N-tritylmorpholine (Frescon, WL 8008). It is shown that the stage of development of Biomphalaria glabrata has a pronounced influence on its susceptibility to N-tritylmorpholine. As the snails grow from hatching to a diameter of 3 mm, the LC50 falls from 0.04 ppm to 0.02 ppm, but further growth results in a progressive increase in LC50 until, at a shell diameter of 20 mm, it is 0.17 ppm. N-Tritylmorpholine is much less toxic to snail eggs when used in short exposures. However, young embryos in capsules treated with 5 ppm for 24 hours developed abnormally and died without hatching. Older embryos developed normally but died after hatching. This delayed effect is attributed to contact, during hatching, with N-tritylmorpholine which is associated with the jelly. The difference in susceptibility between snails and eggs is attributed to a slow rate of penetration of the egg membrane. ImagesFIG. 5 PMID:5300047

Boyce, C. B. C.; Tieze-Dagevos, J. W.; Larman, V. N.

1967-01-01

88

The Effect of Increasing Water Temperatures on Schistosoma mansoni Transmission and Biomphalaria pfeifferi Population Dynamics: An Agent-Based Modelling Study  

PubMed Central

Introduction There is increasing interest in the control and elimination of schistosomiasis. Little is known, however, about the likely effects of increasing water-body temperatures on transmission. Methods We have developed an agent-based model of the temperature-sensitive stages of the Schistosoma and intermediate host snail life-cycles, parameterised using data from S. mansoni and Biomphalaria pfeifferi laboratory and field-based observations. Infection risk is calculated as the number of cercariae in the model, adjusted for their probability of causing infection. Results The number of snails in the model is approximately constant between 15–31°C. Outside this range, snail numbers drop sharply, and the snail population cannot survive outside the range 14–32°C. Mean snail generation time decreases with increasing temperature from 176 days at 14°C to 46 days at 26°C. Human infection risk is highest between 16–18°C and 1 pm and 6–10 pm in calm water, and 20–25°C and 12–4 pm in flowing water. Infection risk increases sharply when temperatures increase above the minimum necessary for sustained transmission. Conclusions The model suggests that, in areas where S. mansoni is already endemic, warming of the water at transmission sites will have differential effects on both snails and parasites depending on abiotic properties of the water-body. Snail generation times will decrease in most areas, meaning that snail populations will recover faster from natural population reductions and from snail-control efforts. We suggest a link between the ecological properties of transmission sites and infection risk which could significantly affect the outcomes of interventions designed to alter water contact behaviour – proposing that such interventions are more likely to reduce infection levels at river locations than lakes, where infection risk remains high for longer. In cooler areas where snails are currently found, increasing temperatures may significantly increase infection risk, potentially leading to new, high-intensity foci of infection. PMID:24987963

McCreesh, Nicky; Booth, Mark

2014-01-01

89

Apple Snails (Ampullariidae)  

NSDL National Science Digital Library

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

Stijn A. I. Ghesquiere

90

Spatial distribution of Biomphalaria mollusks at São Francisco River Basin, Minas Gerais, Brazil, using geostatistical procedures.  

PubMed

Geostatistics is used in this work to make inferences about the presence of the species of Biomphalaria (B. glabrata, B. tenagophila and/or B. straminea), intermediate hosts of Schistosoma mansoni, at the São Francisco River Basin, in Minas Gerais, Brazil. One of these geostatistical procedures, known as indicator kriging, allows the classification of categorical data, in areas where the data are not available, using a punctual sample set. The result is a map of species and risk area definition. More than a single map of the categorical attribute, the procedure also permits the association of uncertainties of the stochastic model, which can be used to qualify the inferences. In order to validate the estimated data of the risk map, a fieldwork in five municipalities was carried out. The obtained results showed that indicator kriging is a rather robust tool since it presented a very good agreement with the field findings. The obtained risk map can be thought as an auxiliary tool to formulate proper public health strategies, and to guide other fieldwork, considering the places with higher occurrence probability of the most important snail species. Also, the risk map will enable better resource distribution and adequate policies for the mollusk control. This methodology will be applied to other river basins to generate a predictive map for Biomphalaria species distribution for the entire state of Minas Gerais. PMID:19046937

Guimarães, Ricardo J P S; Freitas, Corina C; Dutra, Luciano V; Felgueiras, Carlos A; Moura, Ana C M; Amaral, Ronaldo S; Drummond, Sandra C; Scholte, Ronaldo G C; Oliveira, Guilherme; Carvalho, Omar S

2009-03-01

91

Localization of Serotonin in the Nervous System of Biomphalaria glabrata, an Intermediate Host for Schistosomiasis  

PubMed Central

The digenetic trematode Schistosoma mansoni that causes the form of schistosomiasis found in the Western Hemisphere requires the freshwater snail Biomphalaria glabrata as its primary intermediate host. It has been proposed that the transition from the free-living S. mansoni miracidium to parasitic mother sporocyst depends on uptake of biogenic amines, e.g. serotonin, from the snail host. However, little is known about potential sources of serotonin in B. glabrata tissues. This investigation examined the localization of serotonin-like immunoreactivity (5HTli) in the central nervous system (CNS) and peripheral tissues of B. glabrata. Emphasis was placed on the cephalic and anterior pedal regions that are commonly the sites of S. mansoni miracidium penetration. The anterior foot and body wall were densely innervated by 5HTli fibers but no peripheral immunoreactive neuronal somata were detected. Within the CNS, clusters of 5HTli neurons were observed in the cerebral, pedal, left parietal, and visceral ganglia, suggesting that the peripheral serotonergic fibers originate from the CNS. Double-labeling experiments (biocytin backfill × serotonin immunoreactivity) of the tentacular nerve and the three major pedal nerves (Pd n. 10, Pd n. 11, and Pd n. 12) disclosed central neurons that project to the cephalopedal periphery. Overall, the central distribution of 5HTli neurons suggests that, as in other gastropods, serotonin regulates the locomotion, reproductive, and feeding systems of Biomphalaria. The projections to the foot and body wall indicate that serotonin may also participate in defensive, nociceptive, or inflammation responses. These observations identify potential sources of host-derived serotonin in this parasite-host system. PMID:22434538

Delgado, Nadia; Vallejo, Deborah; Miller, Mark W.

2013-01-01

92

Distribution and Schistosoma mansoni infection of Biomphalaria glabrata in different habitats in a rural area in the Jequitinhonha Valley, Minas Gerais, Brazil: environmental and epidemiological aspects.  

PubMed

This paper examines the distribution and infection of Biomphalaria glabrata with Schistosoma mansoni in all aquatic snail habitats in a rural area in the state of Minas Gerais, Brazil, in relation to physico/biotic and behavioral factors. Snail and environmental surveys were carried out semi-annually between July 2001 and November 2002 at 106 sites. Collected snails were examined in the laboratory for infection. B. glabrata densities were highest in overflow ponds, irrigation ponds, springs, canals and wells, and lowest in fishponds and water tanks. Snail densities were higher during the hot, rainy season except for streams and canals and were statistically associated with the presence of fish, pollution, and vegetation density. Tilapia fish and an unidentified Diptera larva were found to be predators of B. glabrata but ducks were not. Twenty-four of the 25 infected snails were collected in 2001(1.4% infection rate) and only one in 2002, after mass chemotherapy. The occurrence of B. glabrata in all 11 snail habitats both at and away from water contact sites studied indicates widespread risk of human infection in the study area. In spite of the strong association between B. glabrata and tilapia in fishponds we do not recommend its use in schistosomiasis control for ecological reasons and its relative inefficiency in streams and dams. PMID:15654420

Kloos, Helmut; Passos, Liana Kanovaloff Janotti; Loverde, Philip; Oliveira, Rodrigo Correa; Gazzinelli, Andréa

2004-11-01

93

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

PubMed Central

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

Mandahl-Barth, G.

1962-01-01

94

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

PubMed

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

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

2014-01-01

95

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

PubMed Central

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

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

2014-01-01

96

Parental Transfer of the Antimicrobial Protein LBP/BPI Protects Biomphalaria glabrata Eggs against Oomycete Infections  

PubMed Central

Vertebrate females transfer antibodies via the placenta, colostrum and milk or via the egg yolk to protect their immunologically immature offspring against pathogens. This evolutionarily important transfer of immunity is poorly documented in invertebrates and basic questions remain regarding the nature and extent of parental protection of offspring. In this study, we show that a lipopolysaccharide binding protein/bactericidal permeability increasing protein family member from the invertebrate Biomphalaria glabrata (BgLBP/BPI1) is massively loaded into the eggs of this freshwater snail. Native and recombinant proteins displayed conserved LPS-binding, antibacterial and membrane permeabilizing activities. A broad screening of various pathogens revealed a previously unknown biocidal activity of the protein against pathogenic water molds (oomycetes), which is conserved in human BPI. RNAi-dependent silencing of LBP/BPI in the parent snails resulted in a significant reduction of reproductive success and extensive death of eggs through oomycete infections. This work provides the first functional evidence that a LBP/BPI is involved in the parental immune protection of invertebrate offspring and reveals a novel and conserved biocidal activity for LBP/BPI family members. PMID:24367257

Baron, Olga Lucia; van West, Pieter; Industri, Benoit; Ponchet, Michel; Dubreuil, Géraldine; Gourbal, Benjamin; Reichhart, Jean-Marc; Coustau, Christine

2013-01-01

97

Parental transfer of the antimicrobial protein LBP/BPI protects Biomphalaria glabrata eggs against oomycete infections.  

PubMed

Vertebrate females transfer antibodies via the placenta, colostrum and milk or via the egg yolk to protect their immunologically immature offspring against pathogens. This evolutionarily important transfer of immunity is poorly documented in invertebrates and basic questions remain regarding the nature and extent of parental protection of offspring. In this study, we show that a lipopolysaccharide binding protein/bactericidal permeability increasing protein family member from the invertebrate Biomphalaria glabrata (BgLBP/BPI1) is massively loaded into the eggs of this freshwater snail. Native and recombinant proteins displayed conserved LPS-binding, antibacterial and membrane permeabilizing activities. A broad screening of various pathogens revealed a previously unknown biocidal activity of the protein against pathogenic water molds (oomycetes), which is conserved in human BPI. RNAi-dependent silencing of LBP/BPI in the parent snails resulted in a significant reduction of reproductive success and extensive death of eggs through oomycete infections. This work provides the first functional evidence that a LBP/BPI is involved in the parental immune protection of invertebrate offspring and reveals a novel and conserved biocidal activity for LBP/BPI family members. PMID:24367257

Baron, Olga Lucia; van West, Pieter; Industri, Benoit; Ponchet, Michel; Dubreuil, Géraldine; Gourbal, Benjamin; Reichhart, Jean-Marc; Coustau, Christine

2013-01-01

98

Bleeding of pulmonate snails.  

PubMed

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

Cooper, J E

1994-07-01

99

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

100

Differential transcriptomic responses of Biomphalaria glabrata (Gastropoda, Mollusca) to bacteria and metazoan parasites, Schistosoma mansoni and Echinostoma paraensei (Digenea, Platyhelminthes)  

PubMed Central

A 70-mer oligonucleotide-based microarray (1152 features) that emphasizes stress and immune responses factors was constructed to study transcriptomic responses of the snail Biomphalaria glabrata to different immune challenges. In addition to sequences with relevant putative ID and Gene Ontology (GO) annotation, the array features non-immune factors and unknown B. glabrata ESTs for functional gene discovery. The transcription profiles of B. glabrata (3 biological replicates, each a pool of 5 snails) were recorded at 12 hours post wounding, exposure to Gram negative or Gram positive bacteria (Escherichia coli and Micrococcus luteus, respectively), or infection with compatible trematode parasites (S. mansoni or E. paraensei, 20 miracidia/snail), relative to controls, using universal reference RNA. The data were subjected to Significance Analysis for Microarrays (SAM), with a false positive rate (FPR) ?10%. Wounding yielded a modest differential expression profile (27 up/21 down) with affected features mostly dissimilar from other treatments. Partially overlapping, yet distinct expression profiles were recorded from snails challenged with E. coli (83 up/20 down) or M. luteus (120 up/42 down), mostly showing up-regulation of defense and stress-related features. Significantly altered expression of selected immune features indicates that B. glabrata detects and responds differently to compatible trematodes. Echinostoma paraensei infection was associated mostly with down regulation of many (immune-) transcripts (42 up/68 down), whereas S. mansoni exposure yielded a preponderance of up-regulated features (140 up/23 down), with only few known immune genes affected. These observations may reflect the divergent strategies developed by trematodes during their evolution as specialized pathogens of snails to negate host defense responses. Clearly, the immune defenses of B. glabrata distinguish and respond differently to various immune challenges. PMID:19962194

Adema, Coen M; Hanington, Patrick C.; Lun, Cheng-Man; Rosenberg, George H.; Aragon, Anthony D; Stout, Barbara A; Richard, Mara L. Lennard; Gross, Paul S.; Loker, Eric S

2009-01-01

101

The Nuclear Receptors of Biomphalaria glabrata and Lottia gigantea: Implications for Developing New Model Organisms  

PubMed Central

Nuclear receptors (NRs) are transcription regulators involved in an array of diverse physiological functions including key roles in endocrine and metabolic function. The aim of this study was to identify nuclear receptors in the fully sequenced genome of the gastropod snail, Biomphalaria glabrata, intermediate host for Schistosoma mansoni and compare these to known vertebrate NRs, with a view to assessing the snail's potential as a invertebrate model organism for endocrine function, both as a prospective new test organism and to elucidate the fundamental genetic and mechanistic causes of disease. For comparative purposes, the genome of a second gastropod, the owl limpet, Lottia gigantea was also investigated for nuclear receptors. Thirty-nine and thirty-three putative NRs were identified from the B. glabrata and L. gigantea genomes respectively, based on the presence of a conserved DNA-binding domain and/or ligand-binding domain. Nuclear receptor transcript expression was confirmed and sequences were subjected to a comparative phylogenetic analysis, which demonstrated that these molluscs have representatives of all the major NR subfamilies (1-6). Many of the identified NRs are conserved between vertebrates and invertebrates, however differences exist, most notably, the absence of receptors of Group 3C, which includes some of the vertebrate endocrine hormone targets. The mollusc genomes also contain NR homologues that are present in insects and nematodes but not in vertebrates, such as Group 1J (HR48/DAF12/HR96). The identification of many shared receptors between humans and molluscs indicates the potential for molluscs as model organisms; however the absence of several steroid hormone receptors indicates snail endocrine systems are fundamentally different. PMID:25849443

Kaur, Satwant; Jobling, Susan; Jones, Catherine S.; Noble, Leslie R.; Routledge, Edwin J.; Lockyer, Anne E.

2015-01-01

102

Usnic Acid Potassium Salt: An Alternative for the Control of Biomphalaria glabrata (Say, 1818)  

PubMed Central

In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been tested as alternatives for the control or eradication of mollusks. The literature describes the antitumor, antimicrobial and antiviral properties of usnic acid as well as other important activities of common interest between medicine and the environment. However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota. Thus, the aim of the present study was to test the potassium salt of usnic acid (potassium usnate) with regard to molluscicidal activity and toxicity to brine shrimp (Artemia salina). To obtain potassium usnate, usnic acid was extracted with diethyl ether isolated and purified from the lichen Cladonia substellata. Biological assays were performed with embryos and adult snails of B. glabrata exposed for 24 h to the usnate solution solubilized in dechlorinated water at 2.5; 5 and 10 µg/ml for embryos, 0.5; 0.9; 1;5 and 10 µg/ml for mollusks and 0.5; 1; 5; 10 µg/ml for A. salina. The lowest lethal concentration for the embryos and adult snails was 10 and 1 µg/ml, respectively. No toxicity to A. salina was found. The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata. PMID:25375098

Lima, Vera L. M.; Pereira, Eugênia C.; Falcão, Emerson P. S.; Melo, Ana M. M. A.; da Silva, Nicácio Henrique

2014-01-01

103

Usnic acid potassium salt: an alternative for the control of Biomphalaria glabrata (Say, 1818).  

PubMed

In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been tested as alternatives for the control or eradication of mollusks. The literature describes the antitumor, antimicrobial and antiviral properties of usnic acid as well as other important activities of common interest between medicine and the environment. However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota. Thus, the aim of the present study was to test the potassium salt of usnic acid (potassium usnate) with regard to molluscicidal activity and toxicity to brine shrimp (Artemia salina). To obtain potassium usnate, usnic acid was extracted with diethyl ether isolated and purified from the lichen Cladonia substellata. Biological assays were performed with embryos and adult snails of B. glabrata exposed for 24 h to the usnate solution solubilized in dechlorinated water at 2.5; 5 and 10 µg/ml for embryos, 0.5; 0.9; 1;5 and 10 µg/ml for mollusks and 0.5; 1; 5; 10 µg/ml for A. salina. The lowest lethal concentration for the embryos and adult snails was 10 and 1 µg/ml, respectively. No toxicity to A. salina was found. The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata. PMID:25375098

Martins, Mônica C B; Silva, Monique C; Silva, Luanna R S; Lima, Vera L M; Pereira, Eugênia C; Falcão, Emerson P S; Melo, Ana M M A; da Silva, Nicácio Henrique

2014-01-01

104

Involvement of protein kinase C signalling and mitogen-activated protein kinase in the amebocyte-producing organ of Biomphalaria glabrata (Mollusca).  

PubMed

Mechanisms that regulate hemocyte production in molluscs, at either the organismal or cellular levels, are not well understood. In the present study, 24-h saline cultures of the amebocyte-producing organ (APO) of the schistosome-transmitting snail Biomphalaria glabrata were used to test for the potential involvement of protein kinase C (PKC) signalling in hematopoiesis. Exposure to phorbol myristate acetate (PMA), an activator of PKC, resulted in an increase in the number of dividing hematopoietic cells in APOs from schistosome-resistant Salvador snails. PMA-induced cell division was blocked by treatment with U0126, an inhibitor of the mitogen-activated protein kinase kinase, MEK1/2. These results suggest that PKC-induced activation of the mitogen-activated protein kinase, ERK1/2, is involved in cell division in the APO. PMID:19183562

Salamat, Zahra; Sullivan, John T

2009-06-01

105

Digenean-gastropod host associations inform on aspects of specific immunity in snails.  

PubMed

Gastropod immunology is informed importantly by the study of the frequent encounters snails endure with digeneans (digenetic trematodes). One of the hallmarks of gastropod-digenean associations is their specificity: any particular digenean parasite species is transmitted by a limited subset of snail taxa. We discuss the nature of this specificity, including its immunological basis. We then review studies of the model gastropod Biomphalaria glabrata indicating that the baseline responses of snails to digeneans can be elevated in a specific manner. Studies incorporating molecular and functional approaches are then highlighted, and are further suggestive of the capacity for specific gastropod immune responses. These studies have led to the compatibility polymorphism hypothesis: the interactions between diversified fibrinogen-related proteins (FREPs) and diverse carbohydrate-decorated polymorphic parasite antigens determine recognition and trigger specific immunity. Complex glycan structures are also likely to play a role in the host specificity typifying snail-digenean interactions. We conclude by noting the dynamic and consequential interactions between snails and digeneans can be considered as drivers of diversification of digenean parasites and in the development and maintenance of specific immunity in gastropods. PMID:25034871

Adema, C M; Loker, E S

2015-02-01

106

Large-scale determinants of intestinal schistosomiasis and intermediate host snail distribution across Africa: does climate matter?  

PubMed

The geographical ranges of most species, including many infectious disease agents and their vectors and intermediate hosts, are assumed to be constrained by climatic tolerances, mainly temperature. It has been suggested that global warming will cause an expansion of the areas potentially suitable for infectious disease transmission. However, the transmission of infectious diseases is governed by a myriad of ecological, economic, evolutionary and social factors. Hence, a deeper understanding of the total disease system (pathogens, vectors and hosts) and its drivers is important for predicting responses to climate change. Here, we combine a growing degree day model for Schistosoma mansoni with species distribution models for the intermediate host snail (Biomphalaria spp.) to investigate large-scale environmental determinants of the distribution of the African S. mansoni-Biomphalaria system and potential impacts of climatic changes. Snail species distribution models included several combinations of climatic and habitat-related predictors; the latter divided into "natural" and "human-impacted" habitat variables to measure anthropogenic influence. The predictive performance of the combined snail-parasite model was evaluated against a comprehensive compilation of historical S. mansoni parasitological survey records, and then examined for two climate change scenarios of increasing severity for 2080. Future projections indicate that while the potential S. mansoni transmission area expands, the snail ranges are more likely to contract and/or move into cooler areas in the south and east. Importantly, we also note that even though climate per se matters, the impact of humans on habitat play a crucial role in determining the distribution of the intermediate host snails in Africa. Thus, a future contraction in the geographical range size of the intermediate host snails caused by climatic changes does not necessarily translate into a decrease or zero-sum change in human schistosomiasis prevalence. PMID:22142789

Stensgaard, Anna-Sofie; Utzinger, Jürg; Vounatsou, Penelope; Hürlimann, Eveline; Schur, Nadine; Saarnak, Christopher F L; Simoonga, Christopher; Mubita, Patricia; Kabatereine, Narcis B; Tchuem Tchuenté, Louis-Albert; Rahbek, Carsten; Kristensen, Thomas K

2013-11-01

107

A water snail catches a ride on STS-90 as part of Neurolab  

NASA Technical Reports Server (NTRS)

A water snail (Biomphalaria glabrata), like those that are part of the Neurolab payload on Space Shuttle Mission STS-90, is held up for inspection in the Operations and Checkout Building. The snails will fly in the Closed Equilibrated Biological Aquatic System (CEBAS) Minimodule, a middeck locker-sized fresh water habitat, designed to allow the controlled incubation of aquatic species in a self-stabilizing, artifical ecosystem for up to three weeks under space conditions. Investigations during the Neurolab mission will focus on the effects of microgravity on the nervous system. The crew of STS-90, slated for launch April 16 at 2:19 p.m. EDT, includes Commander Richard Searfoss, Pilot Scott Altman, Mission Specialists Richard Linnehan, D.V.M., Dafydd (Dave) Williams, M.D., and Kathryn (Kay) Hire, and Payload Specialists Jay Buckey, M.D., and James Pawelczyk, Ph.D.

1998-01-01

108

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

PubMed Central

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

Malek, Emile A.; File, Sharon K.

1971-01-01

109

The biology of Biomphalaria choanomphala and B. sudanica in relation to their role in the transmission of Schistosoma mansoni in Lake Victoria at Mwanza, Tanzania.  

PubMed

A study of the intermediate snail hosts of Schistosoma mansoni in Lake Victoria at Mwanza, Tanzania, was begun in October 1969, the main aims being to investigate the distribution and seasonal variations in population densities of Biomphalaria choanomphala and B. sudanica in relation to the nature of the lake bottom and the biological features of the lake shore, the factors influencing variations in the intensity of S. mansoni transmission along the Mwanza shoreline, and the age structure of populations of B. choanomphala. Field surveys were made at 70 sites near Mwanza and in nearby bays, B. choanomphala being collected from the lake bottom by means of a wire-mesh dredge. Variations in the distribution and population density of B. choanomphala were correlated with the nature of the bottom and its depth profiles at depths of 0.5-6.0 m. Approximately 1-20 snails/m(2) were found on mixed sand and mud but only about 1 snail/m(2) on the predominantly muddy bottom farther out from the shore. Seasonal variations in the age structure and fluctuations in the population densities of B. choanomphala of as much as 10-13-fold were observed. A large and a small form of B. choanomphala, possibly ecophenotypes, were found. S. mansoni infection rates in B. choanomphala ranged from 0.2% to 3.3%, suggesting a tendency to higher infection rates in mature snails. PMID:4539821

Magendantz, M

1972-01-01

110

Reduced Susceptibility of a Biomphalaria tenagophila Population to Schistosoma mansoni after Introducing the Resistant Taim/RS Strain of B. tenagophila into Herivelton Martins Stream  

PubMed Central

Studies performed in the last 30 years demonstrated that a strain of B. tenagophila from the Taim Biological Reserve is completely resistant to Schistosoma mansoni infection. This resistance to parasite infection is a dominant characteristic during crossbreeding with susceptible B. tenagophila strains. These experiments also identified a 350 bp molecular marker that is exclusive to the Taim strain and does not occur in other geographic strains of this snail species. The Taim strain (Taim/RS) of Biomphalaria tenagophila was bred on a large scale, physically marked and introduced into a stream in which previous malacological analyses had revealed the presence of only parasite-susceptible B. tenagophila. Samples of offspring captured 4, 11 and 14 months after the introduction of the Taim strain were examined, and the susceptibility of the snails to S. mansoni infection dropped from 38.6–26.5% to 2.1% during the 14 months after the introduction of the Taim snail strain. A significant correlation was also observed between the absence of infection and the identification of the Taim molecular marker. These results demonstrate that the genetic marker from the Taim strain was successfully introduced into the wild snail population. In addition, a significant relationship exists between the marker and resistance to infection. PMID:24941324

Marques, Daisymara Priscila de Almeida; Rosa, Florence Mara; Maciel, Engels; Negrão-Corrêa, Deborah; Teles, Horácio Manuel Santana; Caldeira, Roberta Lima; Jannotti-Passos, Liana Konovaloff; Coelho, Paulo Marcos Zech

2014-01-01

111

Revised karyotyping and gene mapping of the Biomphalaria glabrata embryonic (Bge) cell line.  

PubMed

The fresh water snail Biomphalaria glabrata (2n=36) belongs to the taxonomic class Gastropoda (family Planorbidae) and is integral to the spread of the human parasitic disease schistosomiasis. The importance of this mollusc is such that it has been selected as a model molluscan organism for whole genome sequencing. In order to understand the structure and organisation of the B. glabrata's genome it is important that gene mapping studies are established. Thus, we have studied the genomes of two B. glabrata embryonic (Bge) cell line isolates 1 and 2 grown in separate laboratories, but both derived from Eder L. Hansen's original culture from the 1970s. This cell line continues to be an important tool and model system for schistosomiasis and B. glabrata. Using these cell line isolates, we have investigated the genome content and established a revised karyotype based on chromosome size and centromere position for these cells. Unlike the original karyotype (2n=36) established for the cell line, our investigations now show the existence of extensive aneuploidy in both cell line isolates to the extent that the total complement of chromosomes in both greatly exceeds the original cell line's diploid number of 36 chromosomes. The isolates, designated Bge 1 and 2, had modal chromosome complements of 64 and 67, respectively (calculated from 50 metaphases). We found that the aneuploidy was most pronounced, for both isolates, amongst chromosomes of medium metacentric morphology. We also report, to our knowledge for the first time using Bge cells, the mapping of single-copy genes peroxiredoxin (BgPrx4) and P-element induced wimpy testis (piwi) onto Bge chromosomes. These B. glabrata genes were mapped onto pairs of homologous chromosomes using fluorescence in situ hybridization (FISH). Thus, we have now established a FISH mapping technique that can eventually be utilized for physical mapping of the snail genome. PMID:19133265

Odoemelam, Edwin; Raghavan, Nithya; Miller, Andrè; Bridger, Joanna M; Knight, Matty

2009-05-01

112

3D-Ultrastructure, Functions and Stress Responses of Gastropod (Biomphalaria glabrata) Rhogocytes  

PubMed Central

Rhogocytes are pore cells scattered among the connective tissue of different body parts of gastropods and other molluscs, with great variation in their number, shape and size. They are enveloped by a lamina of extracellular matrix. Their most characteristic feature is the “slit apparatus”, local invaginations of the plasma membrane bridged by cytoplasmic bars, forming slits of ca. 20 nm width. A slit diaphragm creates a molecular sieve with permeation holes of 20×20 nm. In blue-blooded gastropods, rhogocytes synthesize and secrete the respiratory protein hemocyanin, and it has been proposed–though not proven–that in the rare red-blooded snail species they might synthesize and secrete the hemoglobin. However, the cellular secretion pathway for respiratory proteins, and the functional role(s) of the enigmatic rhogocyte slit apparatus are still unclear. Additional functions for rhogocytes have been proposed, notably a role in protein uptake and degradation, and in heavy metal detoxification. Here we provide new structural and functional information on the rhogocytes of the red-blooded freshwater snail Biomphalaria glabrata. By in situ hybridization of mantle tissues, we prove that rhogocytes indeed synthesize hemoglobin. By electron tomography, the first three dimensional (3D) reconstructions of the slit apparatus are provided, showing detail of highly dense material in the cytoplasmic bars close to the slits. By immunogold labelling, we collected evidence that a major component of this material is actin. By genome databank mining, the complete sequence of a B. glabrata nephrin was obtained, and localized to the rhogocytes by immunofluorescence microscopy. The presence of both proteins fit the ultrastructure-based hypothesis that rhogocytes are related to mammalian podocytes and insect nephrocytes. Reactions of the rhogocytes to deprivation of food and cadmium toxification are also documented, and a possible secretion pathway of newly synthesized respiratory proteins through the slit apparatus is discussed. PMID:24971744

Kokkinopoulou, Maria; Güler, M. Alptekin; Lieb, Bernhard; Barbeck, Mike; Ghanaati, Shahram; Markl, Jürgen

2014-01-01

113

Hyperdiverse Gene Cluster in Snail Host Conveys Resistance to Human Schistosome Parasites  

PubMed Central

Schistosomiasis, a neglected global pandemic, may be curtailed by blocking transmission of the parasite via its intermediate hosts, aquatic snails. Elucidating the genetic basis of snail-schistosome interaction is a key to this strategy. Here we map a natural parasite-resistance polymorphism from a Caribbean population of the snail Biomphalaria glabrata. In independent experimental evolution lines, RAD genotyping shows that the same genomic region responds to selection for resistance to the parasite Schistosoma mansoni. A dominant allele in this region conveys an 8-fold decrease in the odds of infection. Fine-mapping and RNA-Seq characterization reveal a <1Mb region, the Guadeloupe Resistance Complex (GRC), with 15 coding genes. Seven genes are single-pass transmembrane proteins with putative immunological roles, most of which show strikingly high nonsynonymous divergence (5-10%) among alleles. High linkage disequilibrium among three intermediate-frequency (>25%) haplotypes across the GRC, a significantly non-neutral pattern, suggests that balancing selection maintains diversity at the GRC. Thus, the GRC resembles immune gene complexes seen in other taxa and is likely involved in parasite recognition. The GRC is a potential target for controlling transmission of schistosomiasis, including via genetic manipulation of snails. PMID:25775214

Tennessen, Jacob A.; Théron, André; Marine, Melanie; Yeh, Jan-Ying; Rognon, Anne; Blouin, Michael S.

2015-01-01

114

Thai koi-hoi snail dish and angiostrongyliasis due to Angiostrongylus cantonensis: Effects of food flavoring and alcoholic drink on the third-stage larvae in infected snail meat.  

PubMed

Human infection with the rat lungworm Angiostrongylus cantonensis (Parastrongylus cantonensis) in Thailand, especially in the northeastern region, is associated with the habit of eating koi-hoi, which contains raw snail meat. Infection results from the snails being carriers of the larval parasite. The present study was conducted to assess the effect of food flavorings in koi-hoi, alcohol, and exposure time of the two variable on the infective larvae of A. cantonensis. Infected Biomphalaria glabrata snails were used for koi-hoi preparation. Raw snail meat was mixed with koi-hoi flavoring and left at room temperature for various time periods ranging from 5 to 60 minutes. At a predetermined time, two pieces of snail meat were removed at random and examined for viability (as determined by motility) of the parasitic third-stage larvae. At the same time, two random pieces of snail meat were removed and treated with 10 mL of a local 40% alcoholic drink for 30 minutes before examination of larval viability. Exposure of infected snail meat for 10 minutes or more to koi-hoi food flavoring resulted in significantly more nonmotile (dying or dead) larvae. Addition of the local alcoholic drink after exposure to the flavoring exerted an additional killing effect on the larvae. Despite long exposure time, both the koi-hoi flavoring and addition of alcoholic drink were not completely effective in killing the infective larvae in the snail meat. Thorough cooking of the food intended for human consumption should still be practiced. PMID:19272010

Eamsobhana, Praphathip; Yoolek, Adisak; Punthuprapasa, Paibulaya; Yong, Hoi-Sen

2009-04-01

115

Biomphalysin, a New ? Pore-forming Toxin Involved in Biomphalaria glabrata Immune Defense against Schistosoma mansoni  

PubMed Central

Aerolysins are virulence factors belonging to the ? pore-forming toxin (?-PFT) superfamily that are abundantly distributed in bacteria. More rarely, ?-PFTs have been described in eukaryotic organisms. Recently, we identified a putative cytolytic protein in the snail, Biomphalaria glabrata, whose primary structural features suggest that it could belong to this ?-PFT superfamily. In the present paper, we report the molecular cloning and functional characterization of this protein, which we call Biomphalysin, and demonstrate that it is indeed a new eukaryotic ?-PFT. We show that, despite weak sequence similarities with aerolysins, Biomphalysin shares a common architecture with proteins belonging to this superfamily. A phylogenetic approach revealed that the gene encoding Biomphalysin could have resulted from horizontal transfer. Its expression is restricted to immune-competent cells and is not induced by parasite challenge. Recombinant Biomphalysin showed hemolytic activity that was greatly enhanced by the plasma compartment of B. glabrata. We further demonstrated that Biomphalysin with plasma is highly toxic toward Schistosoma mansoni sporocysts. Using in vitro binding assays in conjunction with Western blot and immunocytochemistry analyses, we also showed that Biomphalysin binds to parasite membranes. Finally, we showed that, in contrast to what has been reported for most other members of the family, lytic activity of Biomphalysin is not dependent on proteolytic processing. These results provide the first functional description of a mollusk immune effector protein involved in killing S. mansoni. PMID:23555242

Moné, Yves; Allienne, Jean François; Henri, Hélène; Delbecq, Stéphane; Mitta, Guillaume; Gourbal, Benjamin; Duval, David

2013-01-01

116

Biomphalaria straminea (Mollusca: Planorbidae) as an intermediate host of Ribeiroia sp. (Trematoda: Psilostomidae) in Brazil.  

PubMed

Species of Ribeiroia are trematode parasites of birds and mammals that have acquired notoriety since Ribeiroia ondatrae was identified as a cause of mortality and malformations in North American amphibians. Although species of Ribeiroia have been reported in vertebrate hosts in South America, the snails involved in its transmission remain unknown in Brazil. During malacological studies conducted at Pampulha Reservoir, Belo Horizonte, Minas Gerais, Brazil, between January 2009 and February 2012, in total 14,264 specimens of Biomphalaria straminea were collected, of which 192 (1.35%) were infected with gymnocephalous cercariae. The larvae were used for experimental infection of laboratory-reared guppies ( Poecilia reticulata ); metacercariae obtained in these fishes were orally administered to domestic ducks (Cairina moschata); and adult parasites were obtained from the proventriculus 10 days after infection. Based on morphological and molecular analyses, the parasite was identified as Ribeiroia sp., a species morphologically similar to R. ondatrae , but distinctly different at the molecular level. This is the first report of larvae of Ribeiroia in Brazil and B. straminea as a new intermediate host for this genus. PMID:23421393

Pinto, H A; Jadin, R C; Orlofske, S A; Johnson, P T J; Melo, A L

2013-10-01

117

Lichen endozoochory by snails.  

PubMed

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

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

2011-01-01

118

Lichen Endozoochory by Snails  

PubMed Central

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

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

2011-01-01

119

Small Snails, Enormous Elephants  

NSDL National Science Digital Library

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

2012-06-26

120

Eye to Eye With Garden Snails  

NSDL National Science Digital Library

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

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

1994-07-30

121

Effects of Cu/Zn Superoxide Dismutase (sod1) Genotype and Genetic Background on Growth, Reproduction and Defense in Biomphalaria glabrata  

PubMed Central

Resistance of the snail Biomphalaria glabrata to the trematode Schistosoma mansoni is correlated with allelic variation at copper-zinc superoxide dismutase (sod1). We tested whether there is a fitness cost associated with carrying the most resistant allele in three outbred laboratory populations of snails. These three populations were derived from the same base population, but differed in average resistance. Under controlled laboratory conditions we found no cost of carrying the most resistant allele in terms of fecundity, and a possible advantage in terms of growth and mortality. These results suggest that it might be possible to drive resistant alleles of sod1 into natural populations of the snail vector for the purpose of controlling transmission of S. mansoni. However, we did observe a strong effect of genetic background on the association between sod1 genotype and resistance. sod1 genotype explained substantial variance in resistance among individuals in the most resistant genetic background, but had little effect in the least resistant genetic background. Thus, epistatic interactions with other loci may be as important a consideration as costs of resistance in the use of sod1 for vector manipulation. PMID:22724037

Bonner, Kaitlin M.; Bayne, Christopher J.; Larson, Maureen K.; Blouin, Michael S.

2012-01-01

122

Effects of infection by larvae of Angiostrongylus cantonensis (Nematoda, Metastrongylidae) on the lipid metabolism of the experimental intermediate host Biomphalaria glabrata (Mollusca: Gastropoda).  

PubMed

Experimental infection of Biomphalaria glabrata by Angiostrongylus cantonensis induces significant changes in the concentrations of triacylglycerol and cholesterol in the hemolymph and of neutral lipids in the digestive gonad-gland (DGG) complex of the host snail. In this study, snails were dissected after 1, 2, and 3 weeks of infection to collect the hemolymph and DGG and to measure the levels of cholesterol and triacylglycerol in the hemolymph and neutral lipid fractions in the tissues. The results show that infection by this nematode resulted in a significant decrease in the concentrations of both cholesterol and triacylglycerol in the hemolymph of B. glabrata during the parasite's initial ontogenic development period. This reduction indicates the possible use of these molecules by both parasite and host not only as energy substrates but also as structural factors required during development of the parasite's larval stages. In parallel, changes in the neutral lipid profile in the DGG and lipase activity of the infected snails were observed, indicating the importance of these molecules for successful infection. PMID:23377121

Tunholi-Alves, Vinícius Menezes; Tunholi, Victor Menezes; Gôlo, Patrícia; Lima, Mariana; Garcia, Juberlan; Júnior, Arnaldo Maldonado; Pontes, Emerson Guedes; Bittencourt, Vânia Rita Elias Pinheiro; Pinheiro, Jairo

2013-05-01

123

Baldomero Olivera: Cone Snail Peptides  

NSDL National Science Digital Library

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

Olivera, Baldomero

124

Effect of crude lipopolysaccharide from Escherichia coli O127:B8 on the amebocyte-producing organ of Biomphalaria glabrata (Mollusca).  

PubMed

Lipopolysaccharide (LPS) is a pathogen associated molecular pattern (PAMP) to which the internal defense system (IDS) of both vertebrates and invertebrates responds. We measured the mitotic response of the hematopoietic tissue of the schistosome-transmitting snail, Biomphalaria glabrata, to crude LPS from Escherichia coli 0127:B8. In a dose-response study, snails were injected with a range of concentrations of crude LPS, and mitotic figures were enumerated in histological sections of amebocyte-producing organ (APO) fixed at 24h post-injection (PI) following a 6h treatment with 0.1% colchicine. In APOs from Salvador strain snails, which are genetically resistant to infection with Schistosoma mansoni, LPS concentrations of 0.01 mg/ml and above triggered a large increase in mitotic activity, whereas in APOs from schistosome-susceptible NIH albino snails, concentrations of 0.1mg/ml elicited a much smaller, but statistically significant increase. A time course study, without colchicine treatment, revealed that in Salvador APOs the mitotic response to 0.1mg/ml occurred by 18 h PI, peaked at 24h, and returned to control levels by 72 h; NIH albino APOs showed no detectible response. When Salvador APOs were exposed to crude LPS in vitro, no increase in mitotic activity occurred, a result suggesting the possible requirement for a peripheral tissue or hemolymph factor. The increased cell proliferation induced by crude LPS represents a novel systemic response of an invertebrate IDS to one or more PAMPs from a Gram-negative bacterium. PMID:21530581

Sullivan, John T; Bulman, Christina A; Salamat, Zahra

2011-11-01

125

Susceptibility of Biomphalaria straminea from Peixe Angical dam, Tocantins, Brazil to infection with three strains of Schistosoma mansoni.  

PubMed

Environmental changes from water resource developmental projects affect the epidemiology of water-associated diseases, as well as malaria and schistosomiasis. Aiming to investigate the occurrence and distribution of freshwater snails of medical and veterinary importance in the area of influence of the Peixe Angical hydroelectric dam, a survey has been conducted over four years (2004-2008). The study has revealed the occurrence of populations of Biomphalaria straminea (Dunker) in all municipalities surrounding the lake. Studies on parasite-mollusc compatibility were undertaken using 35 populations of B. straminea, descendants of specimens obtained from that area and three strains of Schistosoma mansoni (Sambon) (BH, CM and CMO). The main results are as follows: (i) among the 1,314 specimens used, eight had been infected (infection index of 0.6%) with only the BH strain, (ii) for B. straminea populations, the mortality index was 6.8% and, depending on the strain used, the indexes were 4.6%, 8.49% and 19% with BH, CM and CMO strains, respectively, (iii) the infection indexes varied according to the B. straminea populations, ranging from 0-12.5% and (iv) the duration of the precercarial period varied from 25-49 days. These results, in addition to environmental and social changes that took place in the Peixe Angical dam region, indicate the possibility of B. straminea emerging as a schistosomiasis vector in this area. PMID:20721496

Fernandez, Monica Ammon; Thiengo, Silvana Carvalho

2010-07-01

126

Demographic responses to multi-generation cadmium exposure in two strains of the freshwater gastropod, Biomphalaria glabrata.  

SciTech Connect

A life table response experiment (LTRE) was used to quantify the population-level effects of continuous, multi-generation cadmium exposure on two strains of the freshwater gastropod, Biomphalaria glabrata; the parasite resistant BS90 and parasite susceptible NMRI strains. Snails were exposed to waterborne cadmium for three consecutive generations. Survival, growth and reproduction were measured empirically and incorporated into a stage-based, deterministic population model. Cadmium significantly affected hatching success, time to maturity and juvenile and adult survival in both strains. There were significant effects of generation on fecundity, hatching success time to maturity and juvenile survival in NMRI and time to maturity and adult survival in BS90. Cadmium significantly affected the population growth rate, lambda (?), in BS90. Cadmium, generation and the cadmium x generation interaction had significant effects on ? in NMRI. At the high cadmium exposure, ? for NMRI showed a decrease from generation 1 to generation 2 followed by and increase from generation 2 to 3. Lambda in high cadmium BS90 steadily decreased over the three generations while NMRI at this same concentration was similar to the controls. The results indicated that strain-specific differences in response to multi-generation cadmium exposure are evident in B. glabrata. Moreover, effects seen in the first generation are not necessarily indicative of effects in subsequent generations. Changes in ? over the course of the three-generation exposure suggest that acclimation and/or adaptation to cadmium may have occurred, particularly in NMRI at the high cadmium exposure level.

Salice, Christopher J.; Miller, Thomas J.; Roesijadi, Guritno

2008-08-20

127

Identification of protein components of egg masses indicates parental investment in immunoprotection of offspring by Biomphalaria glabrata (Gastropoda, Mollusca)  

PubMed Central

The macromolecules contributed by the freshwater gastropod Biomphalaria glabrata, intermediate host of Schistosoma mansoni, to developing offspring inside egg masses are poorly known. SDS-PAGE fractionated egg mass fluids (EMF) of M line and BB02 B. glabrata were analyzed by MALDI-TOF (MS and tandem MS). A MASCOT database was assembled with EST data from B. glabrata and other molluscs to aid in sequence characterization. Of approximately 20 major EMF polypeptides, 16 were identified as defense-related, including protease inhibitors, a hemocyanin-like factor and tyrosinase (each with possible phenoloxidase activity), extracellular Cu-Zn SOD, two categories of C-type lectins, Gram negative bacteria-binding protein (GNBP), aplysianin/achacin-like protein, as well as versions of lipopolysaccharide binding protein/bacterial permeability increasing proteins (LBP/BPI) that differed from those previously described from hemocytes. Along with two sequences that were encoded by “unknown” ESTs, EMF also yielded a compound containing a vWF domain that is likely involved in defense and a polypeptide with homology to the Aplysia pheromone temptin. Further study of B. glabrata pheromones is warranted as these could be useful in efforts to control these schistosome-transmitting snails. Several of the EMF polypeptides were contained in the albumen gland, the organ that produces most EMF. Thus parental investment of B. glabrata in immunoprotection of its offspring is indicated to be considerable. PMID:19995576

Hathaway, Jennifer J M; Adema, Coen M.; Stout, Barbara A.; Mobarak, Charlotte D; Loker, Eric S

2009-01-01

128

EVALUATION OF THE MOLLUSCICIDAL POTENTIAL OF HYDROALCOHOLIC EXTRACTS OF Jatropha gossypiifolia Linnaeus, 1753 ON Biomphalaria glabrata (Say, 1818)  

PubMed Central

The action of extracts from the stem, leaves, and fruit of Jatropha gossypiifolia on Biomphalaria glabrata was studied by analyzing survival, feeding capacity and oviposition ability. The extracts were obtained by macerating the plant parts in 92% ethanol, which were then evaporated until a dry residue was obtained and phytochemically studied. The molluscicidal activity on B. glabrata was investigated using the procedures recommended by WHO (1965). The amount of food ingested and oviposition were measured during each experiment. The extract of leaves from J. gossypiifolia was shown to be a strong molluscicidal agent, causing 100% mortality of B. glabrata, even in the lowest concentration tested, of 25 ppm. Regarding the fruit extract, there was variation in the mortality, depending on the concentration used (100, 75, 50 and 25 ppm). The snails that were in contact with the fruit extract had significant reduction in feeding and number of embryos in comparison to the control. The stem extract did not present molluscicidal activity nor had any influence on the feeding and oviposition abilities of B. glabrata, in the concentrations tested. In conclusion, the extracts of leaves and fruits of J. gossypiifolia investigated in this work show molluscicidal effect and may be sources of useful compounds for the schistosomiasis control. PMID:25351545

Pereira, Adalberto Alves; França, Clícia Rosane Costa; Oliveira, Dorlam's da Silva; Mendes, Renato Juvino de Aragão; Gonçalves, José de Ribamar Santos; Rosa, Ivone Garros

2014-01-01

129

Description of two new cercariae (an echinostome cercaria and a xiphidiocercaria) procured from Biomphalaria pfeifferi (Krauss) from Nigeria.  

PubMed

During parasitological examination of Biomphalaria pfeifferi snails obtained from Niger state (Nigeria), 2 new types of cercariae were found. They are identified to the level of referring to the major group and described here for the first time. They were examined viable and stained with vital stains as well as fixed in 70% alcohol. They were drawn with a camera lucida and photographed. They are identified as an echinostome cercaria and a xiphidiocercaria. The echinostome is characterized by having a ventral sucker almost double in size the oral one. It has a semicircular structure located beyond the oral sucker. Three pairs of penetration glands are found at the anterior portion of the body. The number of collar spines is relatively large (44-46). The flame cellsare 17 x 2 in number. Two main lateral excretory ducts extend anteriorly, form two typical echinostome loops then pass posteriorly to open together in a diverticulated excretory vesicle. Its tail is relatively long and flattened with 3 fin folds. The tail (640 ?m) is longer than the body (475 ?m). The xiphidiocercaria belongs to the "ornatae" group. It is relatively small (180.5 x 110 ?m) with a long stylet (30 ?m). Its oral sucker is one and half times the size of the ventral sucker. Two excretory ducts extend posteriorly in both sides and become dilated and unite to open in a circular excretoryvesicle. Tail is slender shorter than the body and has a dorso-ventral fin fold. PMID:25597151

Yousif, Fouad; Ayoub, Magda; Tadros, Menerva; El Bardicy, Samia; Abolarinwa, Simon

2014-08-01

130

Evaluation of the molluscicidal potential of hydroalcoholic extracts of Jatropha gossypiifolia Linnaeus, 1753 on Biomphalaria glabrata (Say, 1818).  

PubMed

The action of extracts from the stem, leaves, and fruit of Jatropha gossypiifolia on Biomphalaria glabrata was studied by analyzing survival, feeding capacity and oviposition ability. The extracts were obtained by macerating the plant parts in 92% ethanol, which were then evaporated until a dry residue was obtained and phytochemically studied. The molluscicidal activity on B. glabrata was investigated using the procedures recommended by WHO (1965). The amount of food ingested and oviposition were measured during each experiment. The extract of leaves from J. gossypiifolia was shown to be a strong molluscicidal agent, causing 100% mortality of B. glabrata, even in the lowest concentration tested, of 25 ppm. Regarding the fruit extract, there was variation in the mortality, depending on the concentration used (100, 75, 50 and 25 ppm). The snails that were in contact with the fruit extract had significant reduction in feeding and number of embryos in comparison to the control. The stem extract did not present molluscicidal activity nor had any influence on the feeding and oviposition abilities of B. glabrata, in the concentrations tested. In conclusion, the extracts of leaves and fruits of J. gossypiifolia investigated in this work show molluscicidal effect and may be sources of useful compounds for the schistosomiasis control. PMID:25351545

Pereira Filho, Adalberto Alves; França, Clícia Rosane Costa; Oliveira, Dorlam's da Silva; Mendes, Renato Juvino de Aragão; Gonçalves, José de Ribamar Santos; Rosa, Ivone Garros

2014-01-01

131

The Development of Snail Control Methods on an Irrigated Sugar-Cane Estate in Northern Tanzania*  

PubMed Central

In an attempt to prevent the transmission of Schistosoma mansoni on an irrigated sugar-cane estate, molluscicide experiments were carried out to find the optimum methods for controlling the intermediate-host snails, Biomphalaria pfeifferi. The ease of application of N-tritylmorpholine led to its adoption as the molluscicide of choice for the two separate irrigation systems on the estate. Experiments on the frequency and duration of molluscicide treatments were carried out, and from these it was concluded that 5-day applications of N-tritylmorpholine at 0.025 ppm every 7 weeks might lead to a break in transmission by control of the snails. In another set of trials, drainage ditches were treated alternately with N-tritylmorpholine and niclosamide ethanolamine salt, and although the chemicals differed only slightly in their effect, the latter—being ovicidal—was chosen to be applied at approximately 4 ppm by knapsack sprayer every 8 weeks. Extra treatment of small pools with the same compound was carried out during the long rains when irrigation was unnecessary and most of the canals were dry. It is pointed out that the effect of the control methods on S. mansoni transmission will need to be evaluated by studying the incidence of the disease in the population. PMID:5310954

Fenwick, A.

1970-01-01

132

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

PubMed Central

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

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

2006-01-01

133

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

PubMed

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

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

1989-01-01

134

Eradication of Slugs and Snails  

Microsoft Academic Search

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

A. H. Hall

1932-01-01

135

APPLE SNAILS AS DISEASE VECTORS  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

136

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

137

Toxic effects of Microgramma vacciniifolia rhizome lectin on Artemia salina, human cells, and the schistosomiasis vector Biomphalaria glabrata.  

PubMed

The present study evaluated the toxicity of Microgramma vacciniifolia rhizome lectin (MvRL) to Artemia salina, human tumour cell lines (larynx epidermoid carcinoma Hep-2, NCI-H292 lung mucoepidermoid carcinoma, and chronic myelocytic leukaemia K562), and normal peripheral blood mononuclear cells (PBMCs), as well as to Biomphalaria glabrata embryos and adults. MvRL was toxic to A. salina (LC50=159.9 ?g/mL), and exerted cytotoxic effects on NCI-H292 cells (IC50=25.23 ?g/mL). The lectin (1-100 ?g/mL) did not affect the viability of K562 and Hep-2 tumour cells, as well as of PBMCs. MvRL concentration of 1, 10, and 100 ?g/mL promoted malformations (mainly exogastrulation) in 7.8%, 22.5%, and 27.7% of embryos, respectively, as well as delayed embryo development in 42.0%, 69.5%, and 54.7% of embryos, respectively. MvRL at a concentration of 100 ?g/mL killed B. glabrata embryos (17.7%) and adults (25%). Further, MvRL damaged B. glabrata reproductive processes, which was evidenced by observations that snails exposed to the lectin (100 ?g/mL) deposited fewer eggs than those in the control group, and approximately 40% of the deposited eggs exhibited malformations. Comparison of these results with that from A. salina assay indicates that MvRL is adulticidal at the concentration range which is toxic to environment. In conclusion, the cytotoxicity of MvRL on tumour cell and absence of toxicity to normal cell indicate its potential as chemotherapeutic drug. Also, the study revealed that the lectin is able to promote deleterious effects on B. glabrata embryos at environmentally safe concentrations. PMID:24954527

de Albuquerque, Lidiane Pereira; Pontual, Emmanuel Viana; Santana, Giselly Maria de Sá; Silva, Luanna Ribeiro Santos; Aguiar, Jaciana dos Santos; Coelho, Luana Cassandra Breitenbach Barroso; Rêgo, Moacyr Jesus Barreto de Melo; Pitta, Maira Galdino da Rocha; da Silva, Teresinha Gonçalves; Melo, Ana Maria Mendonça de Albuquerque; Napoleão, Thiago Henrique; Paiva, Patrícia Maria Guedes

2014-10-01

138

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

E-print Network

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

Boyer, Elizabeth W.

139

Snail modulates cell metabolism in MDCK cells  

SciTech Connect

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

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

2013-03-22

140

F-LE Snail Invasion  

NSDL National Science Digital Library

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

2012-05-01

141

Production of apple snail for space diet  

NASA Astrophysics Data System (ADS)

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

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

142

Identification and characterisation of functional expressed sequence tags-derived simple sequence repeat (eSSR) markers for genetic linkage mapping of Schistosoma mansoni juvenile resistance and susceptibility loci in Biomphalaria glabrata  

PubMed Central

Biomphalaria glabrata susceptibility to Schistosoma mansoni has a strong genetic component, offering the possibility for investigating host–parasite interactions at the molecular level, perhaps leading to novel control approaches. The identification, mapping and molecular characterisation of genes that influence the outcome of parasitic infection in the intermediate snail host is, therefore, seen as fundamental to the control of schistosomiasis. To better understand the evolutionary processes driving disease resistance/susceptibility phenotypes, we previously identified polymorphic random amplification of polymorphic DNA and genomic simple sequence repeats from B. glabrata. In the present study we identified and characterised polymorphic expressed simple sequence repeats markers (Bg-eSSR) from existing B. glabrata expressed sequence tags. Using these markers, and with previously identified genomic simple sequence repeats, genetic linkage mapping for parasite refractory and susceptibility phenotypes, the first known for B. glabrata, was initiated. Data mining of 54,309 expressed sequence tag, produced 660 expressed simple sequence repeats of which dinucleotide motifs (TA)n were the most common (37.88%), followed by trinucleotide (29.55%), mononucleotide (18.64%) and tetranucleotide (10.15%). Penta- and hexanucleotide motifs represented <3% of the Bg-eSSRs identified. While the majority (71%) of Bg-eSSRs were monomorphic between resistant and susceptible snails, several were, however, useful for the construction of a genetic linkage map based on their inheritance in segregating F2 progeny snails derived from crossing juvenile BS-90 and NMRI snails. Polymorphic Bg-eSSRs assorted into six linkage groups at a logarithm of odds score of 3. Interestingly, the heritability of four markers (Prim1_910, Prim1_771, Prim6_1024 and Prim7_823) with juvenile snail resistance were, by t-test, significant (P < 0.05) while an allelic marker, Prim24_524, showed linkage with the juvenile snail susceptibility phenotype. On the basis of our results it is possible that the gene(s) controlling juvenile resistance and susceptibility to S. mansoni infection in B. glabrata are not only on the same linkage group but lie within a short distance (42 cM) of each other. PMID:23643514

Ittiprasert, Wannaporn; Miller, André; Su, Xin-zhuan; Mu, Jianbing; Bhusudsawang, Ganlayarat; Ukoskit, Kitipat; Knight, Matty

2013-01-01

143

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

PubMed

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

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

1991-09-01

144

Susceptibility of Biomphalaria straminea (Dunker, 1848) from Serra da Mesa Dam, Goiás, Brazil to infection with three strains of Schistosoma mansoni Sambon, 1907.  

PubMed

Ecological changes from water resources development projects often affect the epidemiology of water-associated diseases. In order to investigate the occurrence and distribution of freshwater snails of medical and veterinary importance in the area of influence of the Serra da Mesa Hydroelectric a survey has been performed since 1997 and revealed the occurrence of well-established populations of Biomphalaria straminea (Dunker, 1848) in the 8 municipalities surrounding the lake. Areas of epidemiologic risk for schistosomiasis were selected and studies of parasite-mollusc compatibility were undertaken using specimens from 19 populations of B. straminea and 3 strains (CM, EC and PB) originally isolated from B. straminea. Among 1,135 specimens used 15 became infected (infection index of 1.3%) and 8 populations were susceptible to the schistosome strains: B. straminea from Campinorte (Castelão, susceptible to CM and EC strains, and Planeta Agua, EC strain), Colinas (Tocantinzinho river, CM and EC strains), Minaçu (Canabrava river, EC strain), Niquelândia (Codemin, CM and PB strains, and Almas river, CM strain), Uruaçu (touristic area, PB strain) and Santa Rita do Novo Destino (Maranhão river, CM and EC strains). These results, associated with marked social and ecological changes occurred, strongly suggest the possibility of B. straminea coming to act as a vector of schistosomiasis in the studied area. PMID:12426596

Fernandez, Monica Ammon; Thiengo, Silvana Carvalho

2002-01-01

145

Controlling slugs and snails in orchids  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

146

Inquiry, Land Snails, and Environmental Factors  

ERIC Educational Resources Information Center

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

Barrow, Lloyd H.; Krantz, Patrick D.

2005-01-01

147

Environmental calcium modifies induced defences in snails.  

PubMed Central

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

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

2004-01-01

148

Biomphalaria straminea and Biomphalaria glabrata (Mollusca: Planorbidae) as new intermediate hosts of the fish eyefluke Austrodiplostomum compactum (Trematoda: Diplostomidae) in Brazil.  

PubMed

Austrodiplostomum compactum has been involved in cases of ocular diplostomiasis in several species of fish in Brazil, but the molluscan intermediate hosts of the parasite remain unknown. In the present study, malacological surveys were carried out at Pampulha Reservoir, Belo Horizonte, Minas Gerais, Brazil, between January 2009 and July 2012. A total of 16,119 specimens of Biomphalaria spp. were collected and examined, of which 68/14,948 specimens (0.45%) of Biomphalaria straminea and 6/541 (1.11%) of Biomphalaria glabrata were found harboring a strigeid cercariae. Groups of 5 specimens of Cyprinius carpio were experimentally infected with these cercariae (100 larvae/fish), and metacercariae were recovered from the eyes of the fish, 65 days after infection, with a mean intensity of infection of 10.4 (8-13) metacercariae/fish. Morphological study on cercariae and metacercariae identified them as A. compactum . This is the first record of cercariae of A. compactum in Brazil, and B. straminea and B. glabrata as new intermediate hosts for the parasite. PMID:23360402

Pinto, H A; Melo, A L

2013-08-01

149

Ultrastructural study of the in vitro interaction between Biomphalaria glabrata hemocytes and Schistosoma mansoni miracidia  

Microsoft Academic Search

Biomphalaria glabrata and Schistosoma mansoni relationship was studied by light microscopy (LM) and freeze- fracture replica technique (FFR). We observed very thin cytoplasmic extensions of hemocytes in the LM, which then surround immobilize the miracidia. FFR images showed that the contact site between hemocytes cytoplasmic extensions and the external tegumentary coat involved only superficial layers of miracidia. Numerous vacuoles and

Wolfan Araque; Emilia E Barrios; Pedro Rodríguez; Víctor S Delgado; Héctor J Finol

2003-01-01

150

Size Polymorphism in Alleles of the Myoglobin Gene from Biomphalaria Mollusks  

PubMed Central

Introns are common among all eukaryotes, while only a limited number of introns are found in prokaryotes. Globin, globin-like proteins are widely distributed in nature, being found even in prokaryotes, a wide range of patterns of intron-exon have been reported in several eukaryotic globin genes. Globin genes in invertebrates show considerable variation in the positions of introns; globins can be found without introns, with only one intron or with three introns in different positions. In this work we analyzed the introns in the myoglobin gene from Biomphalaria glabrata, B. straminea, B. tenagophila. In the Biomphalaria genus, the myoglobin gene has three introns; these were amplified by PCR, analyzed by PCR-RFLP. Results showed that the size (number or nucleotides), the nucleotide sequence of the coding gene of the myoglobin are variable in the three species. We observed the presence of size polymorphisms in intron 2, 3; this characterizes a homozygous/heterozygous profile, it indicates the existence of two alleles which are different in size in each species of Biomphalaria. This polymorphism could be explored for specific identification of Biomphalaria individuals. PMID:24710092

Teixeira, Kádima N.; Souza, Karyne N.; Vidigal, Teofânia H.D.A.; Brito, Cristiane A.; Santos, Alexandre M.C.; Santoro, Marcelo M.

2010-01-01

151

Spatial distribution of Biomphalaria mollusks at São Francisco River Basin, Minas Gerais, Brazil, using geostatistical procedures  

Microsoft Academic Search

Geostatistics is used in this work to make inferences about the presence of the species of Biomphalaria (B. glabrata, B. tenagophila and\\/or B. straminea), intermediate hosts of Schistosoma mansoni, at the São Francisco River Basin, in Minas Gerais, Brazil. One of these geostatistical procedures, known as indicator kriging, allows the classification of categorical data, in areas where the data are

Ricardo J. P. S. Guimarães; Corina C. Freitas; Luciano V. Dutra; Carlos A. Felgueiras; Ana C. M. Moura; Ronaldo S. Amaral; Sandra C. Drummond; Ronaldo G. C. Scholte; Guilherme Oliveira; Omar S. Carvalho

2009-01-01

152

Cercarial Dermatitis Transmitted by Exotic Marine Snail  

PubMed Central

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

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

2010-01-01

153

Haemolymph Components of Infected & None Infected Lymnaea snails with Xiphidiocercariae  

PubMed Central

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

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

2011-01-01

154

Snail destabilizes cell surface Crumbs3a.  

PubMed

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

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

2012-08-01

155

The role of Snail in prostate cancer  

PubMed Central

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

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

2012-01-01

156

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

157

Trematode infection alters the antipredator behavior of a pulmonate snail  

Microsoft Academic Search

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

RANDALL J. BERNOT

2003-01-01

158

Snail populations in arctic lakes: competition mediated by predation?  

Microsoft Academic Search

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

Anne E. Hershey

1990-01-01

159

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

E-print Network

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

Reimchen, Thomas E.

160

Images of Minute Minnesota Land Snails Matt Barthel  

E-print Network

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

Nekola, Jeffrey C.

161

Epigenetic Regulation of EMT: The Snail Story  

PubMed Central

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

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

2014-01-01

162

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

PubMed Central

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

Wada, Shinichiro; Chiba, Satoshi

2013-01-01

163

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

164

Biological invasions: the case of planorbid snails  

Microsoft Academic Search

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

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

2005-01-01

165

What happens when snails get sick?  

NSDL National Science Digital Library

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

American Association for the Advancement of Science (AAAS; )

2004-07-09

166

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

PubMed

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

Osuala, F O; Okwuosa, V N

1993-02-01

167

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

PubMed Central

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

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

2014-01-01

168

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

E-print Network

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

Burks, Romi

169

Competitive displacement of a detritivorous salt marsh snail  

Microsoft Academic Search

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

Sarah C. Lee; Brian Reed Silliman

2006-01-01

170

Karyological Studies of Biomphalaria tenagophila (d'Orbigny, 1835) (Gastropoda: Planobidae) from Rio de Janeiro, Brazil  

PubMed Central

The karyotypes of Biomphalaria tenagophila collected from Rio de Janeiro, Brazil were studied using the air-drying method. Somatic cells of this species had 2n=36. The 18 chromosome pairs were identified and classified into 3 groups. The diploid cell has 7 pairs of metacentric, 8 pairs of submetacentric, and 3 pairs of subtelocentric chromosomes. Observed chromosomes ranged from 2.4 to 6.4 µm, and the total length was 122.3 µm. This is the first report on the chromosome of B. tenagophila. PMID:25246727

Yong, Tai-Soon

2014-01-01

171

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

PubMed Central

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

Najarian, H. H.

1961-01-01

172

Fecundity of the Chinese mystery snail in a Nebraska reservoir  

USGS Publications Warehouse

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

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

2013-01-01

173

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

174

How a single gene twists a snail.  

PubMed

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

Kuroda, Reiko

2014-10-01

175

Dragonfly predators influence biomass and density of pond snails.  

PubMed

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

Turner, Andrew M; Chislock, Michael F

2007-08-01

176

The Snail Resource of the Eastern Berin9 Sea  

E-print Network

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

177

Competitive displacement and predation between introduced and native mud snails  

Microsoft Academic Search

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

Margaret Seluk Race

1982-01-01

178

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

179

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

E-print Network

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

180

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

181

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

182

Octopamine boosts snail locomotion: behavioural and cellular analysis.  

PubMed

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

Ormshaw, Jennifer C; Elliott, Christopher J H

2006-12-01

183

The Mitochondrial Genome of the Venomous Cone Snail Conus consors  

PubMed Central

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

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

2012-01-01

184

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

E-print Network

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

Johnson, Steven G.

185

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

E-print Network

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

DeWitt, Thomas J.

186

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

Microsoft Academic Search

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

Glenn A. Goodfriend; Jerry J. Stipp

1983-01-01

187

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

188

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

189

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

190

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

E-print Network

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

McIntyre, Peter

191

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

Microsoft Academic Search

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

Randall W. Oplinger; Eric J. Wagner

2009-01-01

192

Modeling snail breeding in Bioregenerative Life Support System  

NASA Astrophysics Data System (ADS)

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

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

193

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

Microsoft Academic Search

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

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

2012-01-01

194

Crawling beneath the free surface: Water snail locomotion  

E-print Network

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

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

2008-06-23

195

Chiral Speciation in Terrestrial Pulmonate Snails  

PubMed Central

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

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

2012-01-01

196

[Ecological observations on Biomphalaria straminea (Dunker, 1848) in areas of the northeast, Brazil].  

PubMed

The different climatic regions determine the zoogeographic distribution of various animal species depending on their particular conditions and ecological preferences. The host schistosomiasis planorbid is one of these species. This paper deals with the distribution of Biomphalaria straminea in northeast Brazil. It starts from the analysis of different climatic peculiarities in this region, associated to limnological observation done by the author in three different hydric collections in the state of Sergipe. It has been concluded that this is an "eurióioca" species. Its broad ecological valence permits this species to survive in regions where climate asperties are evident, requiring behavior and physiological adaptations. The species survives in all northeast region, from "zona da mata", in the coast, to the semi-arid "sertão". PMID:3509188

Rosas, E

1987-01-01

197

The Role of Snail in EMT and Tumorigenesis  

PubMed Central

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

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

2014-01-01

198

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

199

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

Microsoft Academic Search

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

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

2007-01-01

200

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

PubMed Central

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

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

2013-01-01

201

Controlled Chaos of Polymorphic Mucins in a Metazoan Parasite (Schistosoma mansoni) Interacting with Its Invertebrate Host (Biomphalaria glabrata)  

Microsoft Academic Search

Invertebrates were long thought to possess only a simple, effective and hence non-adaptive defence system against microbial and parasitic attacks. However, recent studies have shown that invertebrate immunity also relies on immune receptors that diversify (e.g. in echinoderms, insects and mollusks (Biomphalaria glabrata)). Apparently, individual or population-based polymorphism-generating mechanisms exists that permit the survival of invertebrate species exposed to parasites.

Emmanuel Roger; Christoph Grunau; Raymond J. Pierce; Hirohisa Hirai; Benjamin Gourbal; Richard Galinier; Rémi Emans; Italo M. Cesari; Céline Cosseau; Guillaume Mitta

2008-01-01

202

METHODS FOR EXCLUDING SLUGS AND SNAILS ON EXPORTED HORTICULTURAL COMMODITIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

203

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

204

Effect of Molasses on Golden Apple Snail Silage Production  

Microsoft Academic Search

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

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

205

Sequestration of lichen compounds by three species of terrestrial snails  

Microsoft Academic Search

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

Sonja Hesbacher; Bruno Baur; Anette Baur; Peter Proksch

1995-01-01

206

A Mathematical Model of Schistosoma mansoni in  Biomphalaria glabrata with Control Strategies  

Microsoft Academic Search

We describe and analyze a mathematical model for schistosomiasis in which infected snails are distinguished from susceptible\\u000a through increased mortality and no reproduction. We based the model on the same derivation as Anderson and May (J. Anim. Ecol.\\u000a 47:219–247, 1978), Feng and Milner (A New Mathematical Model of Schistosomiasis, Mathematical Models in Medical and Health Science, Nashville,\\u000a TN, 1997. Innov. Appl. Math.,

Ruijun Zhao; Fabio Augusto Milner

2008-01-01

207

Foci of Schistosoma mansoni in Assiut province in middle Egypt.  

PubMed

Following detection of Schistosoma mansoni in a 12 years old boy who had both schistosomal polyposis and periportal fibrosis with hepatosplenomegaly, epidemiological studies to confirm local transmission were performed in his and 30 other villages in Assiut Governorate, Egypt. The index case's brother and 6 of 380 inhabitants of his village who provided stool specimens were infected with S. mansoni and a farmer with dysentery and hepatosplenomegaly had a positive rectal snip biopsy. All had hepatic abnormalities on ultrasound examination. Two of 221 schoolchildren in another village had mixed infections with S. mansoni and S. haematobium; 17 others had only S. haematobium. None of 419 inhabitants living near the infected boys had S. mansoni infection. Snails from canals and drains near both villages were netted, identified, counted and checked for infection: in the second village one of 1039 Bulinus truncatus was infected with Schistosoma sp. but none of 859 Biomphalaria alexandrina was infected. Schistosomiasis mansoni is being focally transmitted in 2 villages in Assiut Governorate and appears to be spreading from Lower to Middle and Upper Egypt. We believe B. alexandrina, which has been present in some of the waterways for at least 15 years, were infected recently by local inhabitants returning from Iraq or by cattle traders or military recruits from the Delta. PMID:8249064

Medhat, A; Abdel-Aty, M A; Nafeh, M; Hammam, H; Abdel-Samia, A; Strickland, G T

1993-01-01

208

Camouflaged or tanned: plasticity in freshwater snail pigmentation.  

PubMed

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

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

2013-10-23

209

Camouflaged or tanned: plasticity in freshwater snail pigmentation  

PubMed Central

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

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

2013-01-01

210

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

Microsoft Academic Search

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

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

2007-01-01

211

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

Microsoft Academic Search

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

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

2012-01-01

212

A conserved role for Snail as a potentiator of active transcription  

PubMed Central

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

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

2014-01-01

213

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

PubMed

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

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

2010-01-01

214

Functional Changes in the Snail Statocyst System Elicited by Microgravity  

PubMed Central

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

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

2011-01-01

215

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

216

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

Code of Federal Regulations, 2012 CFR

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

2012-10-01

217

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

Code of Federal Regulations, 2011 CFR

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

2011-10-01

218

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

219

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

Code of Federal Regulations, 2014 CFR

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

2014-10-01

220

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

E-print Network

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

Grosell, Martin

221

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

Microsoft Academic Search

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

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

2010-01-01

222

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

223

Larvicidal Activity against Aedes aegypti and Molluscicidal Activity against Biomphalaria glabrata of Brazilian Marine Algae.  

PubMed

This study investigated the biological activities of five benthic marine algae collected from Northeastern Region of Brazil. The tested activities included larvicidal activity against Aedes aegypti, molluscicidal activity against Biomphalaria glabrata, and toxicity against Artemia salina. Extracts of Ulva lactuca (Chlorophyta), Padina gymnospora, Sargassum vulgare (Phaeophyta), Hypnea musciformis, and Digenea simplex (Rhodophyta) were prepared using different solvents of increasing polarity, including dichloromethane, methanol, ethanol, and water. Of the extracts screened, the dichloromethane extracts of H. musciformis and P. gymnospora exhibited the highest activities and were subjected to bioassay-guided fractionation in hexane and chloroform. The chloroform fractions of the P. gymnospora and H. musciformis extracts showed molluscicidal activity at values below 40? ? g·mL(-1) (11.1460? ? g·mL(-1) and 25.8689? ? g·mL(-1), resp.), and the chloroform and hexane fractions of P. gymnospora showed larvicidal activity at values below 40? ? g·mL(-1) (29.018? ? g·mL(-1) and 17.230? ? g·mL(-1), resp.). The crude extracts were not toxic to A. salina, whereas the chloroform and hexane fractions of P. gymnospora (788.277? ? g·mL(-1) and 706.990? ? g·mL(-1)) showed moderate toxicity, indicating that the toxic compounds present in these algae are nonpolar. PMID:24688787

Guedes, Elíca Amara Cecília; de Carvalho, Cenira M; Ribeiro Junior, Karlos Antonio Lisboa; Lisboa Ribeiro, Thyago Fernando; de Barros, Lurdiana Dayse; de Lima, Maria Raquel Ferreira; Prado Moura, Flávia de Barros; Goulart Sant'ana, Antônio Euzebio

2014-01-01

224

Population structure and coil dimorphism in a tropical land snail.  

PubMed

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

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

2005-09-01

225

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

Microsoft Academic Search

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

Craig W. Osenberg

1989-01-01

226

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

E-print Network

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

227

Predation and the distribution and abundance of a pulmonate pond snail  

Microsoft Academic Search

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

Kenneth M. Brown; Dennis R. DeVries

1985-01-01

228

Fluorescent pigment distinguishes between sibling snail species.  

PubMed

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

Seki, Keiichi; Wiwegweaw, Amporn; Asami, Takahiro

2008-12-01

229

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

230

Hitchhiking behaviour in the obligatory upstream migration of amphidromous snails  

PubMed Central

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

Kano, Yasunori

2009-01-01

231

MTA3 regulates CGB5 and Snail genes in trophoblast  

SciTech Connect

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

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

2013-04-19

232

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

USGS Publications Warehouse

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

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

2002-01-01

233

In vitro mitotic responses of the amebocyte-producing organ of Biomphalaria glabrata to extracts of Schistosoma mansoni.  

PubMed

Amebocyte-producing organs (APOs) of Biomphalaria glabrata were maintained in nonnutritive saline with, or without, extracts of miracidia and adults of Schistosoma mansoni, and examined histologically. The hematopoietic cells remained viable and showed measurable mitotic activity for up to 6 days, with little evidence of tissue death. APOs accumulated fluid and became swollen by as soon as 24 hr, but no cell exomigration was observed. Parasite extracts elicited an increase in the number of dividing cells in the APO, suggesting that the extract may directly stimulate a response from the hematopoietic cells by providing either nutrients or mitogenic growth factors. PMID:18973421

Salamat, Zahra; Sullivan, John T

2008-10-01

234

Biomphalaria glabrata embryonic cells express a protein with a domain homologous to the lectin domain of mammalian selectins  

Microsoft Academic Search

We have cloned from Biomphalaria glabrata, the intermediate host of the helminth parasite Schistosoma mansoni, a 36-kDa apparent-molecular-mass molecule (BgSel) that shares sequence identity with selectins of the cell-adhesion-molecule\\u000a superfamily. BgSel exhibited in its C-terminal part a putative C-type lectin domain similar to the selectin lectin domain.\\u000a Using antibodies to the recombinant BgSel protein, we demonstrated the presence of BgSel

P. Duclermortier; V. Lardans; E. Serra; F. Trottein; C. Dissous

1999-01-01

235

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

Microsoft Academic Search

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

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

1983-01-01

236

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

237

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

PubMed

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

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

1986-02-01

238

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

PubMed

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

Yadav, Ram P; Singh, Ajay

2011-01-01

239

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

PubMed

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

Krist, A C

2000-04-01

240

Snail coordinately regulates downstream pathways to control multiple aspects of mammalian neural precursor development.  

PubMed

The Snail transcription factor plays a key role in regulating diverse developmental processes but is not thought to play a role in mammalian neural precursors. Here, we have examined radial glial precursor cells of the embryonic murine cortex and demonstrate that Snail regulates their survival, self-renewal, and differentiation into intermediate progenitors and neurons via two distinct and separable target pathways. First, Snail promotes cell survival by antagonizing a p53-dependent death pathway because coincident p53 knockdown rescues survival deficits caused by Snail knockdown. Second, we show that the cell cycle phosphatase Cdc25b is regulated by Snail in radial precursors and that Cdc25b coexpression is sufficient to rescue the decreased radial precursor proliferation and differentiation observed upon Snail knockdown. Thus, Snail acts via p53 and Cdc25b to coordinately regulate multiple aspects of mammalian embryonic neural precursor biology. PMID:24719096

Zander, Mark A; Burns, Sarah E; Yang, Guang; Kaplan, David R; Miller, Freda D

2014-04-01

241

Snail Coordinately Regulates Downstream Pathways to Control Multiple Aspects of Mammalian Neural Precursor Development  

PubMed Central

The Snail transcription factor plays a key role in regulating diverse developmental processes but is not thought to play a role in mammalian neural precursors. Here, we have examined radial glial precursor cells of the embryonic murine cortex and demonstrate that Snail regulates their survival, self-renewal, and differentiation into intermediate progenitors and neurons via two distinct and separable target pathways. First, Snail promotes cell survival by antagonizing a p53-dependent death pathway because coincident p53 knockdown rescues survival deficits caused by Snail knockdown. Second, we show that the cell cycle phosphatase Cdc25b is regulated by Snail in radial precursors and that Cdc25b coexpression is sufficient to rescue the decreased radial precursor proliferation and differentiation observed upon Snail knockdown. Thus, Snail acts via p53 and Cdc25b to coordinately regulate multiple aspects of mammalian embryonic neural precursor biology. PMID:24719096

Zander, Mark A.; Burns, Sarah E.; Yang, Guang; Kaplan, David R.

2014-01-01

242

Euparyphium albuferensis and Echinostoma friedi (Trematoda: Echinostomatidae): experimental cercarial transmission success in sympatric snail communities.  

PubMed

Euparyphium albuferensis and Echinostoma friedi cercarial infectivity to four species of sympatric snails was examined under single- or multiple-choice laboratory conditions to show the level of parasite-snail host compatibility. Radix peregra, Lymnaeafuscus, Physella acuta and Gyraulus chinensis act as second intermediate hosts of both parasite species although different cercarial transmission success (CTS) was observed. In single-host experiments, R. peregra and P. acuta showed a high degree of compatibility with E. albuferensis, while only P. acuta in the case of E. friedi. In two-choice snail communities, a snail with high CTS increased the values of another with low compatibility, in both parasite species. In multiple-choice snail communities, high CTS of some hosts decreased, while low CTS of other hosts increased. The degree of parasite-host compatibility of each snail species could be determined by the presence of other snails in the community. PMID:18666415

Muñoz-Antoli, Carla; Marin, Antoni; Vidal, Amparo; Toledo, Rafael; Esteban, José Guillermo

2008-06-01

243

Effect of amphotericin B on the infection success of Schistosoma mansoni in Biomphalaria1 Yves Mon, Guillaume Mitta, David Duval and Benjamin E.F. Gourbal  

E-print Network

Effect of amphotericin B on the infection success of Schistosoma mansoni in Biomphalaria1 glabrata examined the effect of amphotericin B on larval stages (miracidia and24 primary sporocyst) of the helminth Schistosoma mansoni, the causative agent of human25 schistosomiasis. Amphotericin B (AmB) is a polyene

Paris-Sud XI, Université de

244

Schistosomiasis Control Using Piplartine against Biomphalaria glabrata at Different Developmental Stages  

PubMed Central

Background Schistosomiasis is one of the most significant diseases in tropical countries and affects almost 200 million people worldwide. The application of molluscicides to eliminate the parasite's intermediate host, Biomphalaria glabrata, from infected water supplies is one strategy currently being used to control the disease. Previous studies have shown a potent molluscicidal activity of crude extracts from Piper species, with extracts from Piper tuberculatum being among the most active. Methods and Findings The molluscicidal activity of P. tuberculatum was monitored on methanolic extracts from different organs (roots, leaves, fruit and stems). The compounds responsible for the molluscicidal activity were identified using 1H NMR and ESIMS data and multivariate analyses, including principal component analysis and partial least squares. These results indicated that the high molluscicidal activity displayed by root extracts (LC50 20.28 µg/ml) was due to the presence of piplartine, a well-known biologically-active amide. Piplartine was isolated from P. tuberculatum root extracts, and the molluscicidal activity of this compound on adults and embryos of B. glabrata was determined. The compound displayed potent activity against all developmental stages of B. glabrata. Next, the environmental toxicity of piplartine was evaluated using the microcrustacean Daphnia similis (LC50 7.32 µg/ml) and the fish Danio rerio (1.69 µg/ml). The toxicity to these organisms was less compared with the toxicity of niclosamide, a commercial molluscicide. Conclusions The development of a new, natural molluscicide is highly desirable, particularly because the commercially available molluscicide niclosamide is highly toxic to some organisms in the environment (LC50 0.25 µg/ml to D. similis and 0.12 µg/ml to D. rerio). Thus, piplartine is a potential candidate for a natural molluscicide that has been extracted from a tropical plant species and showed less toxic to environment. PMID:23755312

Rapado, Ludmila Nakamura; Pinheiro, Alessandro de Sá; Lopes, Priscila Orechio de Moraes Victor; Fokoue, Harold Hilarion; Scotti, Marcus Tullius; Marques, Joaquim Vogt; Ohlweiler, Fernanda Pires; Borrely, Sueli Ivone; Pereira, Carlos Alberto de Bragança; Kato, Massuo Jorge; Nakano, Eliana; Yamaguchi, Lydia Fumiko

2013-01-01

245

Flying shells: historical dispersal of marine snails across Central America  

PubMed Central

The geological rise of the Central American Isthmus separated the Pacific and the Atlantic oceans about 3 Ma, creating a formidable barrier to dispersal for marine species. However, similar to Simpson's proposal that terrestrial species can ‘win sweepstakes routes’—whereby highly improbable dispersal events result in colonization across geographical barriers—marine species may also breach land barriers given enough time. To test this hypothesis, we asked whether intertidal marine snails have crossed Central America to successfully establish in new ocean basins. We used a mitochondrial DNA genetic comparison of sister snails (Cerithideopsis spp.) separated by the rise of the Isthmus. Genetic variation in these snails revealed evidence of at least two successful dispersal events between the Pacific and the Atlantic after the final closure of the Isthmus. A combination of ancestral area analyses and molecular dating techniques indicated that dispersal from the Pacific to the Atlantic occurred about 750 000 years ago and that dispersal in the opposite direction occurred about 72 000 years ago. The geographical distribution of haplotypes and published field evidence further suggest that migratory shorebirds transported the snails across Central America at the Isthmus of Tehuantepec in southern Mexico. Migratory birds could disperse other intertidal invertebrates this way, suggesting the Central American Isthmus may not be as impassable for marine species as previously assumed. PMID:21920976

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

2012-01-01

246

[Evaluation of molluscicidal effect of nicotinanilide against Oncomelania snails].  

PubMed

Both nicotinanilide hydrochloride and nicotinanilide sulfate are water-soluble, their IC50 and LC90 against Oncomelania snails being around 0.3 mg/L and 0.5 mg/L, respectively, during 24 hour exposure at 25 degrees C followed by a 7-day recovery period. The laboratory tests and field trials showed that over 90% of snails were killed within 3 days exposure at 1-2 mg/L, and that 18.4%-100% snails on moist soil were killed at over 20 degrees C, exposed to spraying dosage of 1-2 g/m2 for 1-3 days. The chemical is highly effective against snails eggs at early stage (cell stage). The LC50 of nicotinanilide to Aristichthys nobilis and Pseudorasbora parva is about 200 mg/L. The acute oral LD50 in mice is about 2 g/kg. Plants tolerate the chemical at 1-2 g/m2, but some leaves wilted at greater than or equal to 5 g/m2, dicotyledon in particular. Dermatitis has been reported in individuals frequently exposing to nicotinanilide wettable powder during massive spraying. PMID:1959178

Chen, Z P; Tao, H Q; Hua, D S; Shen, B R; Chan, H L

1991-01-01

247

The snail superfamily of zinc-finger transcription factors  

Microsoft Academic Search

The Snail superfamily of zinc-finger transcription factors is involved in processes that imply pronounced cell movements, both during embryonic development and in the acquisition of invasive and migratory properties during tumour progression. Different family members have also been implicated in the signalling cascade that confers left–right identity, as well as in the formation of appendages, neural differentiation, cell division and

M. Angela Nieto

2002-01-01

248

A new glycosaminoglycan from the giant African snail Achatina fulica.  

PubMed

A new glycosaminoglycan has been isolated from the giant African snail Achatina fulica. This polysaccharide had a molecular weight of 29,000, calculated based on the viscometry, and a uniform repeating disaccharide structure of -->4)-2-acetyl,2-deoxy-alpha-D-glucopyranose (1-->4)-2-sulfo-alpha-L-idopyranosyluronic acid (1-->. This polysaccharide represents a new, previously undescribed glycosaminoglycan. It is related to the heparin and heparan sulfate families of glycosaminoglycans but is distinctly different from all known members of these classes of glycosaminoglycans. The structure of this polysaccharide, with adjacent N-acetylglucosamine and 2-sulfo-iduronic acid residues, also poses interesting questions about how it is made in light of our current understanding of the biosynthesis of heparin and heparan sulfate. This glycosaminoglycan represents 3-5% of the dry weight of this snail's soft body tissues, suggesting important biological roles for the survival of this organism, and may offer new means to control this pest. Snail glycosaminoglycan tightly binds divalent cations, such as copper(II), suggesting a primary role in metal uptake in the snail. Finally, this new polysaccharide might be applied, like the Escherichia coli K5 capsular polysaccharide, to the study of glycosaminoglycan biosynthesis and to the semisynthesis of new glycosaminoglycan analogs having important biological activities. PMID:8662607

Kim, Y S; Jo, Y Y; Chang, I M; Toida, T; Park, Y; Linhardt, R J

1996-05-17

249

Bioconcentration ratio of diazinon by freshwater fish and snail  

Microsoft Academic Search

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

Jun Kanazawa

1978-01-01

250

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

E-print Network

25 8 8 Allying with armored snails: the complete genome 23687004 20109005 TEL: 0138-40-5570 FAX :0138-40-5570 E-mail: nakagawa@fish.hokudai.ac.jp http://micro.fish.hokudai.ac.jp/labs/Site/Scaly-Foot.html #12; 1. 4.5cm 1. #12; 2. #12; 1 2001 4 Van

Tachizawa, Kazuya

251

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

252

Mitochondrial Phylogeny of Extant Hawaiian Tree Snails (Achatinellinae)  

Microsoft Academic Search

Hawaiian tree snails in the endemic subfamily Achatinellinae display a staggering variety of shell colors and banding patterns. Despite numerous attempts to classify this morphological variation, a conclusive phylogeny has not been proposed. To improve conservation efforts, we sought to better understand the species identities and phylogenetic relationships among the extant species of Achatinella and Partulina using partial mitochondrial 16S

Robert W Thacker; Michael G Hadfield

2000-01-01

253

Accelerated Mutation Accumulation in Asexual Lineages of a Freshwater Snail  

E-print Network

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

Neiman, Maurine

254

MOLLUSCICIDAL ACTIVITY OF VULGARONE B AGAINST RAM'S HORN SNAIL  

Technology Transfer Automated Retrieval System (TEKTRAN)

The ram's horn snail (Planorbdella trivolvis) is an intermediate host for a digenetic trematode (Bolbophorus confusus) that has recently been discovered to be a significant problem in commercial catfish (Ictalurus punctatus) production ponds in the Mississippi Delta region of the USA. In these catf...

255

Control of feeding movements in the freshwater snail Planorbis corneus  

Microsoft Academic Search

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

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

1988-01-01

256

Land Snail Ecology and Biogeography of Eastern Maine  

E-print Network

in the state (Nesovitrea binneyana, Planogyra asteriscus, Striatura ferrea, Striatura milium, VertigoLand Snail Ecology and Biogeography of Eastern Maine Vertigo bollesiana Vertigo nylanderi Vertigo bollesiana, and Vertigo ventricosa). In the early 20th Century, Olaf Nylander of Caribou also made extensive

Nekola, Jeffrey C.

257

Sequestration of lichen compounds by three species of terrestrial snails.  

PubMed

Three species of lichen-grazing snails,Balea perversa, Chondria clienta, andHelicigona lapicida, all from the Swedish island of Öland, were found to sequester lichen compounds when feeding on the crustous lichen speciesAspicila calcarea, Caloplaca flavovirescens, Lecanora muralis, Physcia adscendens, Tephromela atra, andXanthoria parietina. The lichen compounds detected in the soft bodies of the snail species analyzed included the anthraquinone parietin, the depside atranorin, as well as a presumable degradation product of the latter. Other lichen compounds such as (+)-usnic acid or ?-collatolic acid were not found in the soft bodies but were only detected in the feces, suggesting selective uptake of lichen compounds by the snails. In individuals ofC. clienta initially fed on the lichenX. parietina, the amount of sequestered parietin decreased over time on a parietin-free diet but was still detectable in the soft bodies after 28 days. In the ovoviviparous land snail,B. perversa, sequestered parietin was transferred from the mother to the eggs in the reproductive tract. PMID:24234022

Hesbacher, S; Baur, B; Baur, A; Proksch, P

1995-02-01

258

The maintenance of hybrids by parasitism in a freshwater snail.  

PubMed

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

Guttel, Yonathan; Ben-Ami, Frida

2014-11-01

259

Survey of Pulmonate Snails of Central Minnesota. I. Lymnaeidae  

Microsoft Academic Search

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

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

1992-01-01

260

Molecular phylogeny and evolution of the cone snails (Gastropoda, Conoidea).  

PubMed

We present a large-scale molecular phylogeny that includes 320 of the 761 recognized valid species of the cone snails (Conus), one of the most diverse groups of marine molluscs, based on three mitochondrial genes (COI, 16S rDNA and 12S rDNA). This is the first phylogeny of the taxon to employ concatenated sequences of several genes, and it includes more than twice as many species as the last published molecular phylogeny of the entire group nearly a decade ago. Most of the numerous molecular phylogenies published during the last 15years are limited to rather small fractions of its species diversity. Bayesian and maximum likelihood analyses are mostly congruent and confirm the presence of three previously reported highly divergent lineages among cone snails, and one identified here using molecular data. About 85% of the species cluster in the single Large Major Clade; the others are divided between the Small Major Clade (?12%), the Conus californicus lineage (one species), and a newly defined clade (?3%). We also define several subclades within the Large and Small major clades, but most of their relationships remain poorly supported. To illustrate the usefulness of molecular phylogenies in addressing specific evolutionary questions, we analyse the evolution of the diet, the biogeography and the toxins of cone snails. All cone snails whose feeding biology is known inject venom into large prey animals and swallow them whole. Predation on polychaete worms is inferred as the ancestral state, and diet shifts to molluscs and fishes occurred rarely. The ancestor of cone snails probably originated from the Indo-Pacific; rather few colonisations of other biogeographic provinces have probably occurred. A new classification of the Conidae, based on the molecular phylogeny, is published in an accompanying paper. PMID:24878223

Puillandre, N; Bouchet, P; Duda, T F; Kauferstein, S; Kohn, A J; Olivera, B M; Watkins, M; Meyer, C

2014-09-01

261

Targeted Inactivation of Snail Family EMT Regulatory Factors by a Co(III)-Ebox Conjugate  

PubMed Central

Snail family proteins are core EMT (epithelial-mesenchymal transition) regulatory factors that play essential roles in both development and disease processes and have been associated with metastasis in carcinomas. Snail factors are required for the formation of neural crest stem cells in most vertebrate embryos, as well as for the migratory invasive behavior of these cells. Snail factors have recently been linked to the formation of cancer stem cells, and expression of Snail proteins may be associated with tumor recurrence and resistance to chemotherapy and radiotherapy. We report that Co(III)-Ebox is a potent inhibitor of Snail- mediated transcriptional repression in breast cancer cells and in the neural crest of Xenopus. We further show that the activity of Co(III)-Ebox can be modulated by temperature, increasing the utility of this conjugate as a Snail inhibitor in model organisms. We exploit this feature to further delineate the requirements for Snail function during neural crest development, showing that in addition to the roles that Snail factors play in neural crest precursor formation and neural crest EMT/migration, inhibition of Snail function after the onset of neural crest migration leads to a loss of neural crest derived melanocytes. Co(III)-Ebox-mediated inhibition therefore provides a powerful tool for analysing the function of these core EMT factors with unparalleled temporal resolution. Moreover, the potency of Co(III)-Ebox as a Snail inhibitor in breast cancer cells suggests its potential as a therapeutic inhibitor of tumor progression and metastasis. PMID:22393397

Harney, Allison S.; Meade, Thomas J.; LaBonne, Carole

2012-01-01

262

Pseudosuccinea columella: age resistance to Calicophoron daubneyi infection in two snail populations  

PubMed Central

Individual infections of Egyptian and French Pseudosuccinea columella with five miracidia of Calicophoron daubneyi were carried out to determine whether this lymnaeid was capable of sustaining larval development of this parasite. On day 42 post-exposure (at 23 °C), infected snails were only noted in groups of individuals measuring 1 or 2 mm in height at miracidial exposure. Snail survival in the 2-mm groups was significantly higher than that noted in the 1-mm snails, whatever the geographic origin of snail population. In contrast, prevalence of C. daubneyi infection was significantly greater in the 1-mm groups (15–20% versus 3.4–4.0% in the 2-mm snails). Low values were noted for the mean shell growth of infected snails at their death (3.1–4.0 mm) and the mean number of cercariae (<9 in the 1-mm groups, <19 in the 2-mm snails). No significant differences between snail populations and snails groups were noted for these last two parameters. Most infected snails died after a single cercarial shedding wave. Both populations of P. columella showed an age resistance to C. daubneyi infection and only juveniles measuring 2 mm or less in shell height at exposure can ensure larval development of this digenean up to cercarial shedding. PMID:25664810

Dar, Yasser; Rondelaud, Daniel; Vignoles, Philippe; Dreyfuss, Gilles

2015-01-01

263

Snail Recruits Ring1B to Mediate Transcriptional Repression and Cell Migration in Pancreatic Cancer Cells  

PubMed Central

Transcriptional repressor Snail is a master regulator of epithelial–mesenchymal transition (EMT), yet the epigenetic mechanism governing Snail to induce EMT is not well understood. Here, we report that in pancreatic ductal adenocarcinoma (PDAC), elevated levels of the ubiquitin E3 ligase Ring1B and Snail, along with elevated monoubiquitination of H2A at K119 (H2AK119Ub1), are highly correlated with poor survival. Mechanistic investigations identified Ring1B as a Snail-interacting protein and showed that the carboxyl zinc fingers of Snail recruit Ring1B and its paralog Ring1A to repress its target promoters. Simultaneous depletion of Ring1A and Ring1B in pancreatic cancer cells decreased Snail binding to the target chromatin, abolished H2AK119Ub1 modification, and thereby compromised Snail-mediated transcriptional repression and cell migration. We found that Ring1B and the SNAG-associated chromatin modifier EZH2 formed distinct protein complexes with Snail and that EZH2 was required for Snail-Ring1A/B recruitment to the target promoter. Collectively, our results unravel an epigenetic mechanism underlying transcriptional repression by Snail, suggest Ring1A/B as a candidate therapeutic target, and identify H2AK119Ub1 as a potential biomarker for PDAC diagnosis and prognosis. Cancer Res; 74(16); 4353-63. ©2014 AACR PMID:24903147

Chen, Jiangzhi; Xu, Hong; Zou, Xiuqun; Wang, Jiamin; Zhu, Yi; Chen, Hao; Shen, Baiyong; Deng, Xiaxing; Zhou, Aiwu; Chin, Y. Eugene; Rauscher, Frank J.; Peng, Chenghong; Hou, Zhaoyuan

2014-01-01

264

Overexpression of Snail in retinal pigment epithelial triggered epithelial-mesenchymal transition.  

PubMed

Snail transcription factor has been implicated as an important regulator in epithelial-mesenchymal transition (EMT) during tumourigenesis and fibrogenesis. Our previous work showed that Snail transcription factor was activated in transforming growth factor ?1 (TGF-?1) induced EMT in retinal pigment epithelial (RPE) cells and may contribute to the development of retinal fibrotic disease such as proliferative vitreoretinopathy (PVR). However, whether Snail alone has a direct role on retinal pigment epithelial-mesenchymal transition has not been investigated. Here, we analyzed the capacity of Snail to drive EMT in human RPE cells. A vector encoding Snail gene or an empty vector were transfected into human RPE cell lines ARPE-19 respectively. Snail overexpression in ARPE-19 cells resulted in EMT, which was characterized by the expected phenotypic transition from a typical epithelial morphology to mesenchymal spindle-shaped. The expression of epithelial markers E-cadherin and Zona occludin-1 (ZO-1) were down-regulated, whereas mesenchymal markers a-smooth muscle actin (a-SMA) and fibronectin were up-regulated in Snail expression vector transfected cells. In addition, ectopic expression of Snail significantly enhanced ARPE-19 cell motility and migration. The present data suggest that overexpression of Snail in ARPE-19 cells could directly trigger EMT. These results may provide novel insight into understanding the regulator role of Snail in the development of retinal pigment epithelial-mesenchymal transition. PMID:24607896

Li, Hui; Li, Min; Xu, Ding; Zhao, Chun; Liu, Guodong; Wang, Fang

2014-03-28

265

Pseudosuccinea columella: age resistance to Calicophoron daubneyi infection in two snail populations.  

PubMed

Individual infections of Egyptian and French Pseudosuccinea columella with five miracidia of Calicophoron daubneyi were carried out to determine whether this lymnaeid was capable of sustaining larval development of this parasite. On day 42 post-exposure (at 23 °C), infected snails were only noted in groups of individuals measuring 1 or 2 mm in height at miracidial exposure. Snail survival in the 2-mm groups was significantly higher than that noted in the 1-mm snails, whatever the geographic origin of snail population. In contrast, prevalence of C. daubneyi infection was significantly greater in the 1-mm groups (15-20% versus 3.4-4.0% in the 2-mm snails). Low values were noted for the mean shell growth of infected snails at their death (3.1-4.0 mm) and the mean number of cercariae (<9 in the 1-mm groups, <19 in the 2-mm snails). No significant differences between snail populations and snails groups were noted for these last two parameters. Most infected snails died after a single cercarial shedding wave. Both populations of P. columella showed an age resistance to C. daubneyi infection and only juveniles measuring 2 mm or less in shell height at exposure can ensure larval development of this digenean up to cercarial shedding. PMID:25664810

Dar, Yasser; Rondelaud, Daniel; Vignoles, Philippe; Dreyfuss, Gilles

2015-01-01

266

Trematode communities in snails can indicate impact and recovery from hurricanes in a tropical coastal lagoon.  

PubMed

In September 2002, Hurricane Isidore devastated the Yucatán Peninsula, Mexico. To understand its effects on the parasites of aquatic organisms, we analyzed long-term monthly population data of the horn snail Cerithidea pliculosa and its trematode communities in Celestún, Yucatán, Mexico before and after the hurricane (February 2001 to December 2009). Five trematode species occurred in the snail population: Mesostephanus appendiculatoides, Euhaplorchis californiensis, two species of the genus Renicola and one Heterophyidae gen. sp. Because these parasites use snails as first intermediate hosts, fishes as second intermediate hosts and birds as final hosts, their presence in snails depends on food webs. No snails were present at the sampled sites for 6 months after the hurricane. After snails recolonised the site, no trematodes were found in snails until 14 months after the hurricane. It took several years for snail and trematode populations to recover. Our results suggest that the increase in the occurrence of hurricanes predicted due to climate change can impact upon parasites with complex life cycles. However, both the snail populations and their parasite communities eventually reached numbers of individuals and species similar to those before the hurricane. Thus, the trematode parasites of snails can be useful indicators of coastal lagoon ecosystem degradation and recovery. PMID:22079832

Aguirre-Macedo, María Leopoldina; Vidal-Martínez, Victor M; Lafferty, Kevin D

2011-11-01

267

Metabolic acceleration in the pond snail Lymnaea stagnalis?  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

268

A speciation gene for left–right reversal in snails results in anti-predator adaptation  

PubMed Central

How speciation genes can spread in a population is poorly understood. In land snails, a single gene for left–right reversal could be responsible for instant speciation, because dextral and sinistral snails have difficulty in mating. However, the traditional two-locus speciation model predicts that a mating disadvantage for the reversal should counteract this speciation. In this study, we show that specialized snake predation of the dextral majority drives prey speciation by reversal. Our experiments demonstrate that sinistral Satsuma snails (Stylommatophora: Camaenidae) survive predation by Pareas iwasakii (Colubroidea: Pareatidae). Worldwide biogeography reveals that stylommatophoran snail speciation by reversal has been accelerated in the range of pareatid snakes, especially in snails that gain stronger anti-snake defense and reproductive isolation from dextrals by sinistrality. Molecular phylogeny of Satsuma snails further provides intriguing evidence of repetitive speciation under snake predation. Our study demonstrates that a speciation gene can be fixed in populations by positive pleiotropic effects on survival. PMID:21139578

Hoso, Masaki; Kameda, Yuichi; Wu, Shu-Ping; Asami, Takahiro; Kato, Makoto; Hori, Michio

2010-01-01

269

Thermal susceptibility of Salmonella in the Moroccan food snail, Helix aspersa.  

PubMed

Thirty samples of 10-15 Helix aspersa food snails were examined for Salmonella by a surface rinsing method and by analysis of whole snails rinsed with 70% ethanol. Thirteen samples were positive by the rinsing method and 6 were positive by whole snail analysis, with this difference being significant (P less than 0.01). Although Salmonella contamination in H. aspersa appeared to be predominantly surface, the pathogen was also found within the snail meat. The ability of surface and subsurface Salmonella organisms to survive in cooked snails was determined in 90 samples. Thermocouple readings indicated that an internal temperature of at least 200 degrees F (93 degrees C) was reached within the snail meat during cooking by a typical recipe. This temperature was sufficient to kill both surface and subsurface Salmonella in 29 samples positive for the pathogen prior to heating. A variety of serotypes representing several somatic groups was isolated. PMID:1194178

Andrews, W H; Wilson, C R

1975-11-01

270

Determination of wing cell fate by the escargot and snail genes in Drosophila.  

PubMed

Inset appendages such as the wing and the leg are formed in response to inductive signals in the embryonic field. In Drosophila, cells receiving such signals initiate developmental programs which allow them to become imaginal discs. Subsequently, these discs autonomously organize patterns specific for each appendage. We here report that two related transcription factors, Escargot and Snail that are expressed in the embryonic wing disc, function as intrinsic determinants of the wing cell fate. In escargot or snail mutant embryos, wing-specific expression of Snail, Vestigial and beta-galactosidase regulated by escargot enhancer were found as well as in wild-type embryos. However, in escargot snail double mutant embryos, wing development proceeded until stage 13, but the marker expression was not maintained in later stages, and the invagination of the primordium was absent. From such analyses, it was concluded that Escargot and Snail expression in the wing disc are maintained by their auto- and crossactivation. Ubiquitous escargot or snail expression induced from the hsp70 promoter rescued the escargot snail double mutant phenotype with the effects confined to the prospective wing cells. Similar DNA binding specificities of Escargot and Snail suggest that they control the same set of genes required for wing development. We thus propose the following scenario for early wing disc development. Prospective wing cells respond to the induction by turning on escargot and snail transcription, and become competent for regulation by Escargot and Snail. Such cells initiate auto- and crossregulatory circuits of escargot and snail. The sustained Escargot and Snail expression then activates vestigial and other target genes that are essential for wing development. This maintains the commitment to the wing cell fate and induces wing-specific cell shape change. PMID:8620833

Fuse, N; Hirose, S; Hayashi, S

1996-04-01

271

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

272

Removal of corallivorous snails as a proactive tool for the conservation of acroporid corals.  

PubMed

Corallivorous snail feeding is a common source of tissue loss for the threatened coral, Acropora palmata, accounting for roughly one-quarter of tissue loss in monitored study plots over seven years. In contrast with larger threats such as bleaching, disease, or storms, corallivory by Coralliophila abbreviata is one of the few direct sources of partial mortality that may be locally managed. We conducted a field experiment to explore the effectiveness and feasibility of snail removal. Long-term monitoring plots on six reefs in the upper Florida Keys were assigned to one of three removal treatments: (1) removal from A. palmata only, (2) removal from all host coral species, or (3) no-removal controls. During the initial removal in June 2011, 436 snails were removed from twelve 150 m(2) plots. Snails were removed three additional times during a seven month "removal phase", then counted at five surveys over the next 19 months to track recolonization. At the conclusion, snails were collected, measured and sexed. Before-After-Control-Impact analysis revealed that both snail abundance and feeding scar prevalence were reduced in removal treatments compared to the control, but there was no difference between removal treatments. Recolonization by snails to baseline abundance is estimated to be 3.7 years and did not differ between removal treatments. Recolonization rate was significantly correlated with baseline snail abundance. Maximum snail size decreased from 47.0 mm to 34.6 mm in the removal treatments. The effort required to remove snails from A. palmata was 30 diver minutes per 150 m(2) plot, compared with 51 min to remove snails from all host corals. Since there was no additional benefit observed with removing snails from all host species, removals can be more efficiently focused on only A. palmata colonies and in areas where C. abbreviata abundance is high, to effectively conserve A. palmata in targeted areas. PMID:25469321

Williams, Dana E; Miller, Margaret W; Bright, Allan J; Cameron, Caitlin M

2014-01-01

273

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

Microsoft Academic Search

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

Pankaj Kumar Tripathi; Ajay Singh

2004-01-01

274

Creosote compounds in snails obtained from Pensacola Bay, Florida, near an onshore hazardous-waste site  

USGS Publications Warehouse

Snails, Thais haemostoma, were collected from two areas offshore in Pensacola Bay, Florida, near an onshore hazardous-waste site. Tissue from the snails was extracted to isolate the lipophilic compounds and analyzed by gas chromatography/mass spectrometry. Along with naturally occurring compounds, the snail tissue contained large concentrations of polycyclic aromatic compounds, such as phenanthrene, acridine, dibenzothiophene, dibenzofuran, and benzo[a]pyrene. Many of these compounds were characteristic of creosote contamination associated with the onshore hazardous-waste site.

Rostad, C.E.; Pereira, W.E.

1987-01-01

275

Snail1 Protein in the Stroma as a New Putative Prognosis Marker for Colon Tumours  

Microsoft Academic Search

Over-expression of Snail1 gene transcriptional repressor promotes an epithelial-to-mesenchymal transition in epithelial tumour cell lines. Expression of Snail1 RNA has been associated to the pathogenesis of a number of malignancies; however, the lack of good monoclonal antibodies against this protein has precluded a definitive analysis of Snail1 protein. In this study, we aimed to determine the expression of this transcriptional

Clara Francí; Manel Gallén; Francesc Alameda; Teresa Baró; Mar Iglesias; Ismo Virtanen; Antonio García de Herreros; Patrick Callaerts

2009-01-01

276

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

277

Snail and Sonic Hedgehog activation in neuroendocrine tumors of the ileum  

Microsoft Academic Search

The transcription factor Snail represses E-cadherin and induces epithelial-mesenchymal transition, a process also exploited by invasive cancer cells. Aberrant Hedgehog (Hh) signaling was recently observed in a variety of epithelial cancers and it has been shown that the Hh target geneGli1 induces expression of Snail. In this study, we examined whether Snail and Sonic Hedgehog (SHH) are expressed in neuroendocrine

Volker Fendrich; Jens Waldmann; Farzad Esni; Annette Ramaswamy; Michael Mullendore; Malte Buchholz; Anirban Maitra; Georg Feldmann

2007-01-01

278

Removal of corallivorous snails as a proactive tool for the conservation of acroporid corals  

PubMed Central

Corallivorous snail feeding is a common source of tissue loss for the threatened coral, Acropora palmata, accounting for roughly one-quarter of tissue loss in monitored study plots over seven years. In contrast with larger threats such as bleaching, disease, or storms, corallivory by Coralliophila abbreviata is one of the few direct sources of partial mortality that may be locally managed. We conducted a field experiment to explore the effectiveness and feasibility of snail removal. Long-term monitoring plots on six reefs in the upper Florida Keys were assigned to one of three removal treatments: (1) removal from A. palmata only, (2) removal from all host coral species, or (3) no-removal controls. During the initial removal in June 2011, 436 snails were removed from twelve 150 m2 plots. Snails were removed three additional times during a seven month “removal phase”, then counted at five surveys over the next 19 months to track recolonization. At the conclusion, snails were collected, measured and sexed. Before-After-Control-Impact analysis revealed that both snail abundance and feeding scar prevalence were reduced in removal treatments compared to the control, but there was no difference between removal treatments. Recolonization by snails to baseline abundance is estimated to be 3.7 years and did not differ between removal treatments. Recolonization rate was significantly correlated with baseline snail abundance. Maximum snail size decreased from 47.0 mm to 34.6 mm in the removal treatments. The effort required to remove snails from A. palmata was 30 diver minutes per 150 m2 plot, compared with 51 min to remove snails from all host corals. Since there was no additional benefit observed with removing snails from all host species, removals can be more efficiently focused on only A. palmata colonies and in areas where C. abbreviata abundance is high, to effectively conserve A. palmata in targeted areas. PMID:25469321

Miller, Margaret W.; Bright, Allan J.; Cameron, Caitlin M.

2014-01-01

279

The role of the transcriptional regulator snail in cell detachment, reattachment and migration  

PubMed Central

In order to metastasize, cancer cells must first detach from the primary tumor, migrate, invade through tissues and attach to a second site. The transcription factor snail is an important mediator of epithelial-mesenchymal transitions and is involved in tumor progression. Recent data have provided evidence for a requirement for snail expression in metastatic dissemination. Although very little is known about the molecular mechanisms governing metastatic dissemination, we review the possible roles of snail expression in this process. We also review the regulation of snail expression. PMID:19287205

2009-01-01

280

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

281

Sexual selection maintains whole-body chiral dimorphism in snails  

PubMed Central

Although the vast majority of higher animals are fixed for one chiral morph or another, the cause for this directionality is known in only a few cases. In snails, for example, rare individuals of the opposite coil are unable to mate with individuals of normal coil, so directionality is maintained by frequency-dependent selection. The snail subgenus Amphidromus presents an unexplained exception, because dextral (D) and sinistral (S) individuals occur sympatrically in roughly equal proportions (so-called ‘antisymmetry’) in most species. Here we show that in Amphidromus there is sexual selection for dimorphism, rather than selection for monomorphism. We found that matings between D and S individuals occur more frequently than expected by chance. Anatomical investigations showed that the chirality of the spermatophore and the female reproductive tract probably allow a greater fecundity in such inter-chiral matings. Computer simulation confirms that under these circumstances, sustained dimorphism is the expected outcome. PMID:17714311

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

2007-01-01

282

Sexual selection maintains whole-body chiral dimorphism in snails.  

PubMed

Although the vast majority of higher animals are fixed for one chiral morph or another, the cause for this directionality is known in only a few cases. In snails, for example, rare individuals of the opposite coil are unable to mate with individuals of normal coil, so directionality is maintained by frequency-dependent selection. The snail subgenus Amphidromus presents an unexplained exception, because dextral (D) and sinistral (S) individuals occur sympatrically in roughly equal proportions (so-called 'antisymmetry') in most species. Here we show that in Amphidromus there is sexual selection for dimorphism, rather than selection for monomorphism. We found that matings between D and S individuals occur more frequently than expected by chance. Anatomical investigations showed that the chirality of the spermatophore and the female reproductive tract probably allow a greater fecundity in such inter-chiral matings. Computer simulation confirms that under these circumstances, sustained dimorphism is the expected outcome. PMID:17714311

Schilthuizen, M; Craze, P G; Cabanban, A S; Davison, A; Stone, J; Gittenberger, E; Scott, B J

2007-09-01

283

Mercury residues in south Florida apple snails (Pomacea paludosa)  

SciTech Connect

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

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

1997-05-01

284

Mercury residues in south Florida apple snails (Pomacea paludosa)  

USGS Publications Warehouse

Mercury concentrations in the sediments of south Florida wetlands have increased three fold in the last century (Rood et al. 1993). Because south Florida is home to many endemic and endangered species, it is important to understand the potential impacts of mercury in this ecosystem's food web. Recent research by Malley et al. (1996) has shown mollusks to be sensitive indicators of methyl mercury which can reflect small differences in background methyl mercury concentrations. In this study, we attempted to determine if the apple snail (Pomacea paludosa) or its eggs are good indicators of bioavailable mercury. Then, using the apple snail as an indicator, we attempted to determine geographic differences in the concentrations of mercury in south Florida.

Eisemann, J.D.; Beyer, W.N.; Bennetts, R.E.; Morton, A.

1997-01-01

285

Multiple paternity in the freshwater snail, Potamopyrgus antipodarum  

PubMed Central

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

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

2012-01-01

286

Neurohormonal control of cardiac activity in the snail, Helix aspersa  

Microsoft Academic Search

1.The characteristics of a cardioactive peptide(s), LCP, were investigated in the snail,Helix aspersa, to determine if LCP functions as a neurohormone.2.Fractionation of isotonic homogenates of the auricle and sub-esophageal ganglia indicate that LCP is associated with microsomal elements, probably granules observed in electron micrographs of the microsomal pellets.3.Ligation experiments carried out under culture conditions suggest that LCP is transported from

Philip E. Lloyd

1978-01-01

287

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

288

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

289

Clonal diversity driven by parasitism in a freshwater snail.  

PubMed

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

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

2013-11-01

290

Phenoloxidase activity of Helix aspersa maxima (garden snail, gastropod) hemocyanin.  

PubMed

The oxygen-transporting protein, hemocyanin (Hc), of the garden snail Helix aspersa maxima (HaH) was isolated and kinetically characterized. Kinetic parameters of the reaction of catalytic oxidation of catechol to quinone, catalyzed by native HaH were determined: the V max value amounted to 22 nmol min(-1) mg(-1), k cat to 1.1 min(-1). Data were compared to those reported for other molluscan Hcs and phenoloxidases (POs). The o-diphenoloxidase activity of the native HaH is about five times higher than the activity determined for the Hcs of the terrestrial snail Helix pomatia and of the marine snail Rapana thomasiana (k cat values of 0.22 and 0.25 min(-1), respectively). The K m values obtained for molluscan Hcs from different species are comparable to those for true POs, but the low catalytic efficiency of Hcs is probably related to inaccessibility of the active sites to potential substrates. Upon treatment of HaH with subtilisin DY, the enzyme activity against substrate catechol was considerably increased. The relatively high proteolytically induced o-diPO activity of HaH allowed using it for preparation of a biosensor for detection of catechol. PMID:24243490

Raynova, Yuliana; Doumanova, Lyuba; Idakieva, Krassimira Nikolova

2013-12-01

291

Occurrence of a blood group A-like substance in eggs of the prosobranch snail Pomacea canaliculata.  

PubMed

In the eggs of the prosobranch snails Pomacea canaliculata and Pomacea insularum a blood group A-like substance has been detected by anti-A from the snails Helix pomatia, Helix aspersa and Cepaea nemoralis. PMID:815102

Uhlenbruck, G; Steinhausen, G; Cheesman, D F; Helm, B

1976-03-15

292

THE BIOCIDE TRIBUTYLTIN REDUCES THE ACCUMULATION OF TESTOSTERONE AS FATTY ACID ESTERS IN THE MUD SNAIL (ILYANASSA OBSOLETA)  

EPA Science Inventory

Imposex, the development of male sex characteristics by female gonochoristic snails, has been documented globally and is causally associated with exposure to the ubiquitous environmental contaminant tributyltin (TBT). Elevated testosterone levels in snails also are associated wit...

293

Field prevalence and laboratory susceptibility of southern Australian land snails to Brachylaima cribbi sporocyst infection.  

PubMed

Brachylaima cribbi is a terrestrial trematode of birds and mammals with helicid and hygromiid land snails reported as first and second intermediate hosts. However, reports describing the first intermediate host range of B. cribbi have been limited to those snail species present in a small number of geographical locations in South Australia. The natural first intermediate host range, distribution and prevalence of B. cribbi in land snails in southern Australia were determined. A total of 6,432 introduced and native land snails were collected from eight geographical districts across 3,000 km of southern Australia and examined microscopically for B. cribbi sporocysts. Four introduced European snails, Theba pisana, Cernuella virgata, Cochlicella acuta and Cochlicella barbara were natural first intermediate hosts. Sporocyst-infected snails were detected in all districts from Victoria to the west coast of South Australia, a distance of over 1,300 km. Natural sporocyst infection was not observed in introduced European snails Microxeromagna armillata and Helix aspersa or in native Australian land snails Succinea australis and Strangesta gawleri. Egg feeding experiments in the laboratory with B. cribbi confirmed the susceptibility of those species of snails found to be natural first intermediate hosts. Of those species not found to be infected in nature, only M. armillata could be infected in the laboratory. Although this study has shown that five different species of European land snails are suitable first intermediate hosts for B. cribbi there are as yet no reports of B. cribbi from these snails in Europe or from other countries where they have been introduced. Further investigations are needed in Europe to clarify the origins of this parasite. PMID:12847918

Butcher, A R; Grove, D I

2003-06-01

294

The effect of isolation on reproduction and growth of Pseudosuccinea columella (Pulmonata: Lymnaeidae): a snail-conditioned water experiment.  

PubMed

A snail-conditioned water experiment was conducted in Pseudosuccinea columella to test the possible role of a chemical interaction between snails on the diminished growth and fecundity rates found for snails raised in pairs compared to those raised in complete isolation. The results permit to discard the hypothesis of an inhibition of growth and reproduction between snails due to factors released into the water. PMID:12386712

Gutiérrez, Alfredo; Yong, Mary; Wong, Lin; Sánchez, Jorge

2002-09-01

295

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

296

EFFECTS OF SNAIL SIZE AND AGE ON THE PREVALENCE AND INTENSITY OF AVIAN SCHISTOSOME INFECTION: RELATING LABORATORY TO FIELD STUDIES  

Microsoft Academic Search

Both the prevalence and intensity of patent infection by avian schistosomes (Trichobilharzia ocellata) increase with increasing size of lymnaeid snails (Stagnicola elrodi) collected in Flathead Lake, Montana. Because the size and age of a snail are positively correlated, snails of different sizes may have experienced differential duration of exposure to and development of infection. Another possibility is that infection itself

Andrea L. Graham

2003-01-01

297

Effects of body size and resource availability on dispersal in a native and a non-native estuarine snail  

Microsoft Academic Search

I manipulated snail densities of two coexisting species of salt marsh snail, Cerithidea californica Haldeman (native) and Batillaria attramentaria Sowerby (non-indigenous) to investigate how resource levels set by intraspecific competition may influence dispersal rates. I used two distinct size classes of the snails (mature and immature) to determine if the effects of competition on dispersal differed between developmental stages of

James E. Byers

2000-01-01

298

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

299

EFFECTS OF DIETARY EXPOSURE TO FOREST PESTICIDES ON THE BROWN GARDEN SNAIL HELIX ASPERSA MULLER  

EPA Science Inventory

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. cephate, atrazine, glyphosate, hexazinone, and picloram were not lethal at concentrations of 5,000 mg/...

300

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. PMID:22910670

Dreyfuss, G.; Vignoles, P.; Rondelaud, D.

2012-01-01

301

[Effect of the population density on growth and regeneration in the snail Achatina fulica].  

PubMed

In the laboratory, the growth rate of the giant African snail Achatina fulica, as estimated by the weight and shell length was shown to decrease when the population density increased from 10 to 60 snails/m2 of the total terrarium area for five months. In the second experiment, when the population density increased from 48 to 193 snails/m2, the growth rate had already decreased by six weeks. In the groups with a high population density the feeding behavior was weakened, expressed by a greater amount of nonconsumed food, according to visual observations, than in the groups with lower population densities. At the population density of 10 to 60 snails/m2, the proliferative activity in the course of the optic tentacle regeneration, as expressed by the mitotic index, did not differ reliably within five months. In the second experiment, the mitotic indices at the population densities of 96 and 193 snails/m2 within 1.5 months exceeded that of 48 snails/m2. Recommendations are given concerning the population density from the viewpoint of commercial growth of the snails. It was proposed that, based on the analysis of the mechanism underlying the inhibition of feeding behavior in populations with extra high densities, one may develop a new approach to the production of chemical agents to control land snails as agricultural pests. PMID:11042956

Sidel'nikov, A P; Stepanov, I I

2000-01-01

302

Differential parasitism of native and introduced snails: replacement of a parasite fauna  

E-print Network

Differential parasitism of native and introduced snails: replacement of a parasite fauna Mark E February 2004 Key words: Batillaria attramentaria, Batillaria cumingi, Cerithidea californica, fish in the introduced Japanese mud snail, Batillaria cumingi (= B. attramentaria), in nearly all of its introduced range

Bermingham, Eldredge

303

Potential of Metriaclima lanisticola (Teleostei: Cichlidae) for biological control of schistosome intermediate host snails  

Microsoft Academic Search

Metriaclima lanisticola, a native cichlid of Lake Malawi, was studied under laboratory conditions to evaluate its possible role as a predator of snails (Bulinus spp.). Bulinus globosus, B. nyassanus and B. tropicus were used as prey. B. globosus and B. nyassanus are intermediate hosts of human schistosomes in Lake Malawi. M. lanisticola orally shelled snails of all three species. Even

Mary Lundeba; Jeremy S. Likongwe; Henry Madsen; Jay R. Stauffer

2007-01-01

304

A Comparison of Black Carp, Redear Sunfish, and Blue Catfish as Biological Controls of Snail Populations  

Microsoft Academic Search

Redear sunfish Lepomis microlophus and blue catfish Ictalurus furcatus were compared with black carp Mylopharyngodon piceus as potential biological controls for rams-horn snails Planorbella spp. Comparisons were made with regard to snail size selection, total consumption, and the effects of alternative prey and temperature on consumption rates of two size-classes for each species, small (?100 mm total length [TL]) and

Jonathan J. Ledford; Anita M. Kelly

2006-01-01

305

Dynamics of Diplostomum spathaceum infection in snail hosts at a fish farm.  

PubMed

Ecologically sustainable disease prevention in intensive monocultures, such as fish farming, is based on the knowledge of the ecology of parasites and the identification of the key proportion of host populations for parasite life cycles. In this paper, we examined the life cycle dynamics of the pathogenic trematode Diplostomum spathaceum at a fish farm during a period of 1 year, focusing especially on the pattern of infection in the snail host (Lymnaea stagnalis) population, which is the key phase in the parasite life cycle regarding preventative actions. We found that (1) the infection varied seasonally in snails, being highest in late August; (2) the prevalence of infection and the proportion of individuals releasing cercariae were strongly dependent on snail size; (3) the parasite over-wintered in snails as dormant sporocysts and 4) the mortality of infected snails was not likely to differ from uninfected individuals during winter. Furthermore, the seasonality and development of the infection in the snails corresponded to the pattern of infection observed in the tracer rainbow trout caged in the farm area. This pattern of infection also indicated strong spatiality of the infection, probably because of differences in the size of the snail population between the ponds rather than differences in the prevalence of infection. Overall, present results indicate a possibility for late-summer outbreaks of D. spathaceum, but also that snail prevention at farms could be conducted more efficiently by considering both size-dependent infection and the timing of cercarial release. PMID:16565817

Karvonen, Anssi; Savolainen, Miia; Seppälä, Otto; Valtonen, E Tellervo

2006-09-01

306

The biological control of snail intermediate hosts of schistosomiasis by fish  

Microsoft Academic Search

Summary The use of molluscivorous fish for biological control of snail intermediate hosts of schistosomiasis is a regularly reappearing theme in the literature on schistosomiasis control. The effectiveness of this control method has not yet been demonstrated, and conclusive field evidence is lacking. In this article the literature on snail control by fish is critically reviewed. Special attention is paid

R. Slootweg; E. A. Malek; F. S. McCullough

1994-01-01

307

Buffering role of the intertidal anemone Anthopleura aureoradiata in cercarial transmission from snails to crabs  

E-print Network

snails to crabs J.V. Hopper, R. Poulin, D.W. Thieltges Department of Zoology, University of Otago, P-host organisms on the transmission of the microphallid trematode Maritrema novaezealandensis from its snail first., 2002). For trematodes, accumulation of metacercariae in crustaceans, molluscs or fish serving as second

Poulin, Robert

308

LETTER Exclusive male care despite extreme female promiscuity and low paternity in a marine snail  

E-print Network

LETTER Exclusive male care despite extreme female promiscuity and low paternity in a marine snail to expectations based on paternity assurance: despite high levels of female promiscuity, males of a marine snail paternity has been characterised, including fishes (Jones et al. 1999, 2001), sea spiders (Barreto & Avise

Grosberg, Rick

309

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

310

Dynamic control of a central pattern generator circuit: a computational model of the snail feeding network  

E-print Network

­Huxley models, Lymnaea stagnalis Abstract Central pattern generators (CPGs) are networks underlying rhythmic to the rhythmogenic circuit. In the feeding system of the pond snail, Lymnaea stagnalis, the extrinsic slow oscillator the CPG-driven motor pattern underlying feeding in the pond snail, Lymnaea (Fig. 1). One type of cell

Feng, Jianfeng

311

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

312

Dry down impacts on apple snail (Pomacea paludosa) demography: Implications for wetland water management  

USGS Publications Warehouse

Florida apple snails (Pomacea paludosa Say) are prey for several wetland-dependent predators, most notably for the endangered Florida snail kite (Rostrhamus sociabilis Vieillot). Management concerns for kites have been raised regarding the impacts of wetland dry downs on snails, but little data exists to validate these concerns. We simulated drying events in experimental tanks, where we observed that snail survival patterns, regardless of hydrology, were driven by a post-reproductive die off. In contrast to earlier reports of little to no dry down tolerance, we found that 70% of pre-reproductive adult-sized snails survived a 12-week dry down. Smaller size classes of snails exhibited significantly lower survival rates (< 50% after eight weeks dry). Field surveys showed that 77% of egg production occurs in April-June. Our hydrologic analyses of six peninsular Florida wetlands showed that most dry downs overlapped a portion of the peak snail breeding season, and 70% of dry downs were ??? 12 weeks in duration. Dry down timing can affect recruitment by truncating annual egg production and stranding juveniles. Dry down survival rates and seasonal patterns of egg cluster production helped define a range of hydrologic conditions that support robust apple snail populations, and illustrate why multiple characteristics of dry down events should be considered in developing target hydrologic regimes for wetland fauna. ?? 2008, The Society of Wetland Scientists.

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

2008-01-01

313

Down-regulation of SNAIL suppresses MIN mouse tumorigenesis: Modulation of apoptosis,  

E-print Network

evidence implicates the SNAIL family of transcriptional repressors in cancer development; however, the role- histochemical analysis of the uninvolved intestinal mucosa for SNAIL and E-cadherin levels along with rates-cadherin, p16INKa, and hMLH-1 (2). This frequently occurs at the transcriptional level, most commonly either

Ottino, Julio M.

314

Structure of terrestrial snail communities of Euro Siberian alder swamps (Cl. Alnetea glutinosae) in Latvia  

Microsoft Academic Search

Studies on the terrestrial snail communities of Euro-Siberian alder swamps (Cl. alnetea glutinosae) of Latvia were carried out during the period of 2004–2005, by examining samples from 12 forest districts located in different parts of the country. In total, 38 species, constituting half of all terrestrial snail species recorded in Latvia, were found. The examined alder swamps can be divided

Digna Pilate

2009-01-01

315

INTRODUCTION Predator avoidance in aquatic snails is facilitated by surfacing and  

E-print Network

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

Grosell, Martin

316

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

317

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

318

Hormetic effects of heavy metals in aquatic snails: is a little bit of pollution good?  

PubMed

Hormesis is the term to describe a stimulatory effects associated with a low dose of a potentially toxic substance or stress. We had anecdotal evidence of hormetic effects in some of our previous experiments concerning the influence of heavy metals on aquatic snail growth and recruitment. We therefore repeated a version of an earlier experiment but this time we expanded our low-dose treatments and increased our sample size. We also explored if metals had a hormetic effect on algae periphyton. We raised snails in outdoor mini-ecosystems containing lead, zinc, and cadmium-contaminated soil from an Environmental Protection Agency Superfund site in the Silver Valley of northern Idaho. The snails came from two sites. One population (Physella columbiana) has evolved for 120 years in the presence of heavy metals and one (Lymnaea palustris) has not. We found that P. columbiana exhibited hormesis with snails exposed to small amounts of metals exhibiting more reproduction and growth than snails not exposed to metals. Naturally occurring Oscillatoria algae also exhibited a hormetic effect of heavy metals but L. palustris did not display hormesis. Large doses negatively impacted all three species. Overall the levels of cadmium, lead, and zinc measured in the tissues of the snails were inversely correlated to the number of snails recruited into the tub populations. Only in comparisons of the lowest metal treatment to the control treatment is a positive effect detected. Indirect effects on competing species of snails, periphyton, and also fishermen, may be less favorable. PMID:18648792

Lefcort, Hugh; Freedman, Zachary; House, Sherman; Pendleton, Mathew

2008-03-01

319

THE EFFECT OF CHEMICAL TREATMENTS ON MELANOIDES TUBERCULATUS, A SNAIL THAT VECTORS AN IMPORTANT FISH TREMATODE  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the United States, Melanoides tuberculatus is a nonindigenous aquatic snail that vectors a trematode infecting both cultured and wild fish species. This snail is now found in 16 states and among other ways is believed to be spread from place to place by the use of contaminated fisheries equipmen...

320

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

321

Snail shells and acid rain - an alternative to marble chips and acid  

Microsoft Academic Search

An original project carried out by a UK year 9 (13-14 year-old) science class is described. The reaction between acid and snail shells was investigated, and the effects of different acids, acid concentration, temperature and shell size were studied. The results were related to the effects of acid rain on snails in the wild. Students responded with interest and the

Sue Howarth

2004-01-01

322

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

SciTech Connect

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

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

2013-12-10

323

Snail modulates the assembly of fibronectin via ?5 integrin for myocardial migration in zebrafish embryos.  

PubMed

The Snail family member snail encodes a zinc finger-containing transcriptional factor that is involved in heart formation. Yet, little is known about how Snail regulates heart development. Here, we identified that one of the duplicated snail genes, snai1b, was expressed in the heart region of zebrafish embryos. Depletion of Snai1b function dramatically reduced expression of ?5 integrin, disrupted Fibronectin layer in the heart region, especially at the midline, and prevented migration of cardiac precursors, resulting in defects in cardiac morphology and function in zebrafish embryos. Injection of ?5?1 protein rescued the Fibronectin layer and then the myocardial precursor migration in snai1b knockdown embryos. The results provide the molecular mechanism how Snail controls the morphogenesis of heart during embryonic development. PMID:24667151

Qiao, Liangjun; Gao, Hongwei; Zhang, Ting; Jing, Lulu; Xiao, Chun; Xiao, Yue; Luo, Ning; Zhu, Hongyan; Meng, Wentong; Xu, Hong; Mo, Xianming

2014-01-01

324

Effects of parasitism and stress on hemolymph protein of the African giant snail, Achatina fulica.  

PubMed

Effects of parasitism and stress on the protein concentration of hemolymph have been investigated using the rat lungworm Angiostromgylus cantonensis in the snail host Achatina fulica. The normal hemolymph protein concentration, averaging 1.77 g/100 ml in noninfected snails, did not show any reduction when the hosts were infected with third stage larvae. When the infected snails were bled repeatedly, protein concentration showed a significant decrease by 0.6 g/100 ml. Starved, infected snails were capable of maintaining their hemolymph protein level within the normal range. This treatment, however, in combination with frequent bleeding, caused much stress to the snails and reduced survival. The number of survivors depended on the frequency of bleeding and on the food level. PMID:735303

Brockelman, C R

1978-10-31

325

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

326

Snails and slugs damaging the cut foliage, Cordyline fruticosa and use of biorationals towards their management.  

PubMed

Snails and slugs became a serious molluscan pests and damaging leaves of purple compacta, Cordyline fruticosa extensively grown for export at Green Farm Ltd, Sri Lanka. The export quality of leaves of C. fruticosa is lowered due to feeding of snails, Achantina fulica (Bowditch), Opeas pyrgula Schmacker and Boettgerx and Helix aspersa Muller and slugs incurring great loss to cut foliage industry. Paucity of information is available to understand snails and slugs damage and their host range that limits to develop suitable management practices. Therefore this study was aimed to determine damage, alternate hosts and to develop possible management practices. Snails and slugs damaged mainly fresh leaves of C. fruticosa. The severity of damage was 44.5% in infested field based on the visual rating method. Leaves of cassava, sting bean, okra, cucumber, passion fruit, papaya, Glyricidia and shoe flower were identified as alternate hosts and neem, Ixora and Dracaena spp were not served as alternate hosts. Among the plant materials tested for their repellence against snails and slugs revealed that neem seed powder was an irritant; neem leaves, mint leaves and Lantana leaves were acted as anti-feedant and Salt as chemical repellent. Among the barrier and bait experiments Bordeaux mixture exhibited a significant barrier effect against horizontal movement of snails. Baits made out of Metaldehyde bait, vegetables bait and jaggery had a strong effect in repelling the snails and slugs. Mulching with Madhuca longifolia punnac was the best to reduce the snails and slugs population compared to M. longifolia seed kernel powder. Oil from M. longifolia failed to reduce their population. Hence the results revealed that saponin containing M. longifolia punnac helped to eliminate snails and slugs when used as mulch. Metaldehyde, vegetable and jaggery baits are also useful to minimize their colonization further. Hence combination of these methods will help to prevent snails and slugs from damaging C. fruticosa and benefit to the cut foliage industry to sustain its export quality. PMID:23885439

Karthiga, S; Jegathambigai, V; Karunarathne, M D S D; Svinningen, A; Mikunthan, G

2012-01-01

327

Speciation and Gene Flow between Snails of Opposite Chirality  

PubMed Central

Left-right asymmetry in snails is intriguing because individuals of opposite chirality are either unable to mate or can only mate with difficulty, so could be reproductively isolated from each other. We have therefore investigated chiral evolution in the Japanese land snail genus Euhadra to understand whether changes in chirality have promoted speciation. In particular, we aimed to understand the effect of the maternal inheritance of chirality on reproductive isolation and gene flow. We found that the mitochondrial DNA phylogeny of Euhadra is consistent with a single, relatively ancient evolution of sinistral species and suggests either recent “single-gene speciation” or gene flow between chiral morphs that are unable to mate. To clarify the conditions under which new chiral morphs might evolve and whether single-gene speciation can occur, we developed a mathematical model that is relevant to any maternal-effect gene. The model shows that reproductive character displacement can promote the evolution of new chiral morphs, tending to counteract the positive frequency-dependent selection that would otherwise drive the more common chiral morph to fixation. This therefore suggests a general mechanism as to how chiral variation arises in snails. In populations that contain both chiral morphs, two different situations are then possible. In the first, gene flow is substantial between morphs even without interchiral mating, because of the maternal inheritance of chirality. In the second, reproductive isolation is possible but unstable, and will also lead to gene flow if intrachiral matings occasionally produce offspring with the opposite chirality. Together, the results imply that speciation by chiral reversal is only meaningful in the context of a complex biogeographical process, and so must usually involve other factors. In order to understand the roles of reproductive character displacement and gene flow in the chiral evolution of Euhadra, it will be necessary to investigate populations in which both chiral morphs coexist. PMID:16149849

2005-01-01

328

Spectroscopic characterization of metallothionein from the terrestrial snail, Helix pomatia.  

PubMed

The Cd-sequestering metallothionein (MT) isoform isolated from the midgut gland of Roman snails exposed to Cd supplements in the feed was characterized by compositional and spectroscopic analysis. The preparations contained nearly 5 mol of Cd, small amounts of Cu and about 1 mol of Zn per chain mass of 6620 Da, in numerical agreement with the apoprotein's measured capacity of firmly binding a maximum of 6 equivalents of Cd per molecule. As with other Cd-containing MTs the occurrence of a prominent Cd-mercaptide-specific shoulder at 250 nm in its absorption spectrum showed that Cd is complexed in tetrahedral symmetry by the cysteine residues of the protein, and the multiphasic ellipticity profile in the CD spectrum revealed that these complexes are joined to form one or more oligonuclear Cd-mercapto clusters. Both spectral features vanished with the removal of the metal but were reconstituted to maximum amplitudes by readdition of Cd to the metal-free apoprotein, provided precautions were taken to prevent air oxidation of the latter. Quantitative analysis of snail MT reconstituted with Cd established that the 18 cysteine side chains bind the metal in a 3-to-1 ratio; spectroscopic studies on fractionally restored forms demonstrated that the six Cd ions were bound to the apoprotein molecule in succession in two sets of three Cd ions each. Thus, one can infer from the observed stoichiometry and the coordinating preferences of Cd that this gastropod MT, like the Cd-bearing MTs of marine crustaceans, harboured the metal in two separate cyclically constructed Cd3Cys9 clusters. The snail clusters differed, however, from other MTs in their response to acidification. Their protolytic dissociation proceeded through two separate protonation steps with the manifestation of spectroscopically distinguishable intermediate forms. Thus, this snail isoform displays in its metal composition and its chemical and spectroscopic features both similarities and differences to other animal kingdom MTs. Its properties suggest that it serves an important role in the protection of the terrestrial gastropod from Cd. PMID:11488904

Dallinger, R; Wang, Y; Berger, B; Mackay, E A; Kägi, J H

2001-08-01

329

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

PubMed

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

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

2010-01-01

330

The repressor function of snail is required for Drosophila gastrulation and is not replaceable by Escargot or Worniu.  

PubMed

Mesoderm formation in the Drosophila embryo depends on the maternal Toll signaling pathway. The Toll pathway establishes the Dorsal nuclear gradient, which regulates many zygotic genes to establish the mesodermal fate and promote the invagination of ventral cells. An important target gene of Dorsal is snail, which is required for proper mesoderm invagination. The Snail protein contains five zinc fingers and is a transcriptional repressor. However, it is not clear whether repressing target genes is a requirement for Snail to control ventral invagination. To examine such requirement, we conducted a series of genetic rescue experiments in snail mutant embryos. Snail, Worniu, and Escargot are closely related zinc-finger proteins and have equal functions during neuroblast development. However, among these three proteins, only Snail can rescue the mesoderm invagination phenotype. Moreover, the ability of various Snail mutant constructs to repress gene expression correlates with their ability to control invagination. This unique property of Snail in mesoderm formation can be attributed mostly to the CtBP co-repressor interaction motifs in the N-terminus, not to the C-terminal DNA-binding zinc fingers. Ectopic expression of Snail outside the ventral domain is not sufficient to induce cell movement even though repression of target genes still occurs. Together, the results show that the repressor function of Snail is essential for gastrulation. The repression of target genes by Snail may permit other factors in the ventral cells to positively promote mesoderm invagination. PMID:15110709

Hemavathy, Kirugaval; Hu, Xiaodi; Ashraf, Shovon I; Small, Stephen J; Ip, Y Tony

2004-05-15

331

The influence of Plagiorchis mutationis larval infection on the cellular immune response of the snail host Lymnaea stagnalis.  

PubMed

The effects of trematode Plagiorchis mutationis parasitism on the cellular immune responses of the snail host Lymnaea stagnalis were investigated. The number of spreading blood cells (hemocytes) from infected snails was significantly less (69.5%) than in uninfected individuals (79.2%). The phagocytic activity of blood cells in infected snails was also significantly less (17.2%) compared to uninfected snails (27.8%). The hemocytes from the infected snails did not form a complete capsule around Sephadex beads in vitro. The protective reactions of the snail hosts were independent of the parasite load (daily cercariae production). In vitro, dead cercariae of P. mutationis were encapsulated by hemocytes from uninfected snails. The hemocytes of the infected snails formed a complete capsule around only 20% of dead cercariae in vitro, with remaining cercariae either unencapsulated (50% of cercariae) or incompletely encapsulated (30% of cercariae). The total number of hemocytes in the infected snails was twofold less than in uninfected individuals. The results of this study showed that the cellular response of snail host L. stagnalis to P. mutationis trematode infection is similar to the previously studied snail-trematode model systems. PMID:24428684

Kryukova, Natalia A; Yurlova, Natalia I; Rastyagenko, Natalia M; Antonova, Elena V; Glupov, Viktor V

2014-06-01

332

PKD1 phosphorylation-dependent degradation of SNAIL by SCF-FBXO11 regulates epithelial-mesenchymal transition and metastasis.  

PubMed

Metastatic dissemination is often initiated by the reactivation of an embryonic development program referred to as epithelial-mesenchymal transition (EMT). The transcription factor SNAIL promotes EMT and elicits associated pathological characteristics such as invasion, metastasis, and stemness. To better understand the posttranslational regulation of SNAIL, we performed a luciferase-based, genome-wide E3 ligase siRNA library screen and identified SCF-FBXO11 as an important E3 that targets SNAIL for ubiquitylation and degradation. Furthermore, we discovered that SNAIL degradation by FBXO11 is dependent on Ser-11 phosphorylation of SNAIL by protein kinase D1 (PKD1). FBXO11 blocks SNAIL-induced EMT, tumor initiation, and metastasis in multiple breast cancer models. These findings establish the PKD1-FBXO11-SNAIL axis as a mechanism of posttranslational regulation of EMT and cancer metastasis. PMID:25203322

Zheng, Hanqiu; Shen, Minhong; Zha, Yin-Lian; Li, Wenyang; Wei, Yong; Blanco, Mario Andres; Ren, Guangwen; Zhou, Tianhua; Storz, Peter; Wang, Hui-Yun; Kang, Yibin

2014-09-01

333

Effects of snail grazing and nutrient release on growth of the macrophytes Ceratophyllum demersum and Elodea canadensis and the filamentous green alga Cladophora sp  

Microsoft Academic Search

The effects of snail (Lymnaea (Galba) turricula) nutrient release and grazing on young macrophytes and filamentous green algae were examined in a laboratory experiment. Snails released an average of 24.2 µg PO4-P and 48.9 µg NH4-N g-1 snail FW d-1. Snails consumed Cladophora sp. at the highest rate (45 mg g-1 snail FW d-1), Elodea canadensis at a lower rate

Agnieszka Pinowska

2002-01-01

334

The mesoderm determinant snail collaborates with related zinc-finger proteins to control Drosophila neurogenesis.  

PubMed

The Snail protein functions as a transcriptional regulator to establish early mesodermal cell fate. Later, in germ band-extended embryos, Snail is also expressed in most neuroblasts. Here we present evidence that this expression of Snail is required for central nervous system (CNS) development. The neural function of snail is masked by two closely linked genes, escargot and worniu. Both Escargot and Worniu contain zinc-finger domains that are highly homologous to that of Snail. Although not affecting expression of early neuroblast markers, the deletion of the region containing all three genes correlates with loss of expression of CNS determinants including fushi tarazu, pdm-2 and even-skipped. Transgenic expression of each of the three Snail family proteins can rescue efficiently the fushi tarazu defects, and partially the pdm-2 and even-skipped CNS patterns. These results demonstrate that the Snail family proteins have essential functions during embryonic CNS development, around the time of ganglion mother cell formation. PMID:10562554

Ashraf, S I; Hu, X; Roote, J; Ip, Y T

1999-11-15

335

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

PubMed Central

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

Chontananarth, Thapana; Wongsawad, Chalobol

2013-01-01

336

Experimental infection of five subspecies of Oncomelania snails with Angiostrongylus cantonensis.  

PubMed

Five subspecies of Oncomelania snails, Oncomelania hupensis nosophora, O.h. hupensis, O.h.chiui, O.h.formosana and O.h.quadrasi, were experimentally exposed to the first stage larvae of Angiostrongylus cantonesis. The presence of third stage larvae was observed in all of the five subspecies of Oncomelania snails 20 days after infection. Infection rates of the third stage larvae of the parasite in Oncomelania snails were 38.0-40.0%. There were no differences in preferences among Oncomelania snails. The third stage larvae in Oncomelania snails almost distributed in kidney and intestine region, and most of the larvae were active and free in tissues. The distribution pattern of the larvae in Oncomelania snails was quite different from that in Achatina fulica and Ampullarium sp. These third stage larvae were ingested by rats, and developed to adults. These data suggest that Oncomelania snails may play important role when A. cantonensis will spread, and indicate the possibility of human infection with A. cantonensis. PMID:9139392

Iwanaga, Y

1995-12-01

337

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

PubMed

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

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

2015-01-01

338

Maternal Inheritance of racemism in the terrestrial snail Bradybaena similaris.  

PubMed

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

Utsuno, Hiroki; Asami, Takahiro

2010-01-01

339

Allying with armored snails: the complete genome of gammaproteobacterial endosymbiont  

PubMed Central

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

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

2014-01-01

340

Suitability of six lymnaeid snails for infection with Fasciola hepatica.  

PubMed

The suitability of Fossaria (Bakerilymnaea) cubensis and Pseudosuccinea columella from Louisiana as intermediate hosts for Fasciola hepatica was compared to P. columella and Stagnicola elodes from Ann Arbor, MI, S. attenuata from Hidalgo, Mexico, Lymnaea gedrosiana from Iran and L. natalensis from Senegal. P. columella from LA was shown to be a more suitable host (51.3% became infected) than F. (B.) cubensis (15.2% and 26.4% of two populations became infected). The infection rate for P. columella from MI, was 50% and for L. gedrosiana was 32.5%, whereas L. natalensis, S. elodes and S. attenuata were refractory. F. (B.) cubensis and P. columella have some degree of suitability as intermediate hosts for F. hepatica under laboratory conditions, but field observations of their habitat in southern LA and characteristic management of cattle indicate that the former snail is more important as an intermediate host in this enzootic area. Tissue sections of suitable snails had few histopathological effects but physical damage caused by rediae was pronounced, mainly in the digestive gland and in the mantle. PMID:3617426

Cruz-Reyes, A; Malek, E A

1987-05-01

341

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

PubMed

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

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

2014-01-01

342

Snail Transcription Factor Regulates Neuroendocrine Differentiation in LNCaP Prostate Cancer Cells  

PubMed Central

Background Snail transcription factor induces epithelial-mesenchymal transition (EMT) via decreased cell adhesion-associated molecules like E-cadherin, and increased mesenchymal markers like vimentin. We previously established Snail-mediated EMT model utilizing androgen-dependent LNCaP cells. These cells express increased vimentin protein and relocalization of E-cadherin from the cell membrane to the cytosol. Interestingly, Snail transfection in LNCaP cells resulted in cells acquiring a neuroendocrine-like morphology with long neurite-like processes. Methods We tested for expression of neuroendocrine markers neuron specific enolase (NSE) and chromogranin A (CgA) by Western blot analysis, and performed proliferation assays to test for paracrine cell proliferation. Results LNCaP cells transfected with Snail displayed increase in the neuroendocrine markers, NSE and CgA as well as translocation of androgen receptor to the nucleus. LNCaP C-33 cells that have been previously published as a Neuroendocrine Differentiation (NED) model exhibited increased expression levels of Snail protein as compared to LNCaP parental cells. Functionally, conditioned medium from the LNCaP-Snail transfected cells increased proliferation of parental LNCaP and PC-3 cells, which could be abrogated by NSE/CgA siRNA. Additionally, NED in LNCaP-C33 cells or that induced in parental LNCaP cells by serum starvation could be inhibited by knockdown of Snail with siRNA. Conclusion Overall our data provide evidence that Snail transcription factor may promote tumor aggressiveness in the LNCaP cells through multiple processes; induction of EMT may be required to promote migration, while NED may promote tumor proliferation by a paracrine mechanism. Therefore, therapeutic targeting of Snail may prove beneficial in not only abrogating EMT but also NED. PMID:20166136

McKeithen, Danielle; Graham, Tisheeka; Chung, Leland W. K.; Odero-Marah, Valerie

2010-01-01

343

[Study on the effect of bromoacetamide upon the development of snail eggs].  

PubMed

This paper deals with the influence of bromoacetamide on the development of snail eggs, its effect on inducing diapause of snail eggs at different developmental stages (blastula, gastrula, trochophore and veliger) both at different concentrations of bromoacetamide at the same time and at same concentration at different times. Besides, the oviposition of the snails and the eggs within snails have also been studied. The results are as follows: 1. When the snail eggs were immersed in bromoacetamide at concentrations of 0.034ppm-0.067ppm, deformation of snail eggs appeared from unicellular to gastrula stages, but it was not observed after the trochophore-veliger stages. When the eggs at different stages were separately immersed in bromoacetamide, they were all found deformed. The molluscicidal concentration for inducing deformation of eggs was higher at the trochophore-veliger and metamophotic stages than that at the blastula and gastrula stages (Figs. 1-5). 2. After immersed in bromoacetamide solution, the development of the snail eggs were obviously retarded. The effects varied with different concentrations. Within the same exposure time, the higher the bromoacetamide concentration, the higher the diapause rate. 3. The longer the immersion time, the lower concentration was needed to delay the development and the lower hatching rate was for the eggs at the same or different stages. 4. After treatment with bromoacetamide, the average number of eggs laid by a female snail was reduced. 5. By using 3H-labeled bromoacetamide, it was found that the radioactivity of 3H-labeled bromoacetamide per hundred snail eggs was raised along with the increasing of the molluscicide concentration.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1303331

Zhang, Y; Guo, Y H

1992-01-01

344

Experimental and Molecular Study of Cercariae of Clinostomum sp. (Trematoda: Clinostomidae) from Biomphalaria spp. (Mollusca: Planorbidae) in Brazil.  

PubMed

Despite the large number of reports of species of Clinostomum from vertebrate hosts in South America, studies evaluating the molluscan transmitters of these parasites are scarce. In the present study, clinostomatoid cercariae shed from 0.02% (4/17,485) specimens of Biomphalaria spp., collected at the Pampulha reservoir, Belo Horizonte, Minas Gerais, Brazil, were used for experimental infection of Poecilia reticulata . Samples of cercariae from molluscs and metacercariae experimentally obtained from fish were subjected to morphological and molecular analyses and compared with species of Clinostomum reported in the Americas. The cercariae and metacercariae, here identified as Clinostomum sp., present general morphology similar to that reported for Clinostomum marginatum , however, from molecular point of view, differ significantly from North American C. marginatum and other species of Clinostomum reported in South America. These results suggest that the diversity of Clinostomum found in Brazil may be underestimated. Additional studies aimed at molecular characterization of South American species of Clinostomum, including the finding of specimens with sequences similar to that reported for C. marginatum in North America are required. PMID:25090192

Pinto, H A; Caffara, M; Fioravanti, M L; Melo, A L

2015-02-01

345

Spermatheca gland extract of snail (Telescopium telescopium) has wound healing potential: an experimental study in rabbits.  

PubMed

The effects of spermatheca gland extract of snail (Telescopium telescopium) to promote wound healing were studied in an animal model. The spermatheca gland extract of the snail was used as a topical medicament to treat experimentally created full thickness wounds in 12 rabbits (Oryctologous cuniculus). Wound healing was assessed on the basis of physical, histomorphological, and histochemical changes on days 0, 3, 7, and 14. Statistically significant differences were observed between the groups in all measured parameters. These exciting findings suggest that the data should be further tested in animal models to better understand the potential for wound healing in the spermatheca gland extract of the marine snail. PMID:19019846

Kumar, Saurabh; Ghosh, Debaki; Biswas, Tuhin Kanti; Dutta, Uttam; Das, Partho; Kundu, Subarna

2008-12-01

346

Snail2 promotes osteosarcoma cell motility through remodelling of the actin cytoskeleton and regulates tumor development  

PubMed Central

The function of Snail2 in mesenchymal tumors is, to date unknown. Using knockdown and overexpression studies, we show that Snail2 regulates migration and invasion of osteosarcoma cells. Knockdown resulted in significantly decreased motility, remodelling of the actin cytoskeleton, and loss of cellular protrusions. Over-expression increased motility, formation of actin-rich cellular protrusions, and altered expression of some non-canonical Wnt pathway components whilst decreasing expression of the adhesion molecule OB-cadherin. Unexpectedly, knockdown also resulted in significantly smaller tumors in an in vivo CAM assay. Therefore Snail2 may be a potential therapeutic target for clinical intervention of osteosarcoma. PMID:23352643

Sharili, Amir-Shaya; Allen, Steve; Smith, Ken; Price, Joanna; McGonnell, Imelda M.

2013-01-01

347

The population density effects on the reproductive biology of the snail Bradybaena similaris (Férussac, 1821) (Mollusca, Gastropoda).  

PubMed

The influence of population density on some aspects of the reproductive biology of the snail Bradybaena similaris was studied. Molluscs were maintained under 0.2 (isolated), 0.3, 0.6, 1.0, 1.3 and 1.7 snail/m(2) densities. The animals maintained under 0.3 and 0.6 snail/m(2) showed the lowest numbers of eggs laid/snail, being the highest value observed to the 1.7 snail/m(2). The hatching of the snails maintained under 0.3 snail/m(2) density, begun at the 21st day after laying, and the maximum time required to the hatching was 36 days was observed to the eggs came from snails maintained under the densities 0.6, 1.0, 1.3 snail/m(2), respectively. The highest percentage hatchability (55.56%) was observed to isolated snails. The galactogen content in the albumen gland did not seem to accompany the alterations occurred in the reproduction of B. similaris in response to the different population densities. PMID:18660965

Oliveira, C S de; Vasconcellos, M C; Pinheiro, J

2008-05-01

348

Effects of snail size and age on the prevalence and intensity of avian schistosome infection: relating laboratory to field studies.  

PubMed

Both the prevalence and intensity of patent infection by avian schistosomes (Trichobilharzia ocellata) increase with increasing size of lymnaeid snails (Stagnicola elrodi) collected in Flathead Lake, Montana. Because the size and age of a snail are positively correlated, snails of different sizes may have experienced differential duration of exposure to and development of infection. Another possibility is that infection itself induces snail gigantism. Each of these possibilities could lead to increased prevalence and intensity of infection among the oldest-largest snails. To decouple size variation from many correlated effects of age and to test for parasite-induced gigantism, laboratory experiments standardized snail size-age-at-infection, exposure history, inoculating dose, and duration of infection. The positive relationship between size and prevalence was eliminated in the laboratory, but the relationship between size and infection intensity remained. Laboratory results thus suggest that infection intensity is related to snail size per se, whereas prevalence in the field is related to snail size only through the correlation between size and age. In addition, under these experimental conditions, infected snails were no larger than uninfected snails, so the patterns observed in the field might not be attributable to gigantism. PMID:12880242

Graham, Andrea L

2003-06-01

349

Central role of Snail1 in the regulation of EMT and resistance in cancer: a target for therapeutic intervention  

PubMed Central

Snail1 is the founding member of the Snail superfamily of zinc-finger transcription factors, which also includes Snail2 (Slug) and Snail3 (Smuc). The superfamily is involved in cell differentiation and survival, two processes central in cancer research. Encoded by the SNAI1 gene located on human chromosome 20q13.2, Snail1 is composed of 264 amino acids and usually acts as a transcriptional repressor. Phosphorylation and nuclear localization of Snail1, governed by PI3K and Wnt signaling pathways crosstalk, are critical in Snail1’s regulation. Snail1 has a pivotal role in the regulation of epithelial-mesenchymal transition (EMT), the process by which epithelial cells acquire a migratory, mesenchymal phenotype, as a result of its repression of E-cadherin. Snail1-induced EMT involves the loss of E-cadherin and claudins with concomitant upregulation of vimentin and fibronectin, among other biomarkers. While essential to normal developmental processes such as gastrulation, EMT is associated with metastasis, the cancer stem cell phenotype, and the regulation of chemo and immune resistance in cancer. Snail1 expression is a common sign of poor prognosis in metastatic cancer, and tumors with elevated Snail1 expression are disproportionately difficult to eradicate by current therapeutic treatments. The significance of Snail1 as a prognostic indicator, its involvement in the regulation of EMT and metastasis, and its roles in both drug and immune resistance point out that Snail1 is an attractive target for tumor growth inhibition and a target for sensitization to cytotoxic drugs. PMID:25084828

2014-01-01

350

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

PubMed Central

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

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

2013-01-01

351

Wet adhesion and adhesive locomotion of snails on anti-adhesive non-wetting surfaces.  

PubMed

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

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

2012-01-01

352

Palatability and chemical defense of Phragmites australis to the marsh periwinkle snail Littoraria irrorata.  

PubMed

Coastal marsh habitats are impacted by many disturbances, including habitat destruction, pollution, and the introduction of invasive species. The common reed, Phragmites australis, has been particularly invasive in the mesohaline regions of the Chesapeake Bay, but few studies have investigated its role in trophic interactions with North American marsh consumers. The marsh periwinkle snail Littoraria irrorata is a common grazer in marshes and grazes on the native grass Spartina alterniflora. Whether this snail grazes on Phragmites has not been addressed. We found Spartina leaves to be tougher than those of Phragmites, but despite this, snails consumed significantly more Spartina than Phragmites. Subsequent experiments demonstrated that Phragmites is chemically deterrent to snails by an unknown, moderately polar, compound. Further studies are required to more fully understand the interactions between Phragmites, herbivores, and Spartina, and how they may impact marsh ecosystems. PMID:21691807

Hendricks, Lindsey G; Mossop, Hannah E; Kicklighter, Cynthia E

2011-08-01

353

Toxicity of imidazolium-based ionic liquids on Physa acuta and the snail antioxidant stress response.  

PubMed

In the present study, the acute and developmental toxicities of imidazolium ionic liquids (ILs) with different alkyl chain lengths, as well as the antioxidant response and lipid peroxidation levels were evaluated in the snail, Physa acuta. Longer alkyl chains corresponded to increased IL toxicity in snails. Long-term IL exposure at lower concentrations inhibited snail growth and reproduction. We also found that IL inhibited the activities of superoxide dismutase (SOD) and glutathione S-transferase (GST), promoted the activity of catalase (CAT), and increased the glutathione content. However, SOD, GST, and CAT activities returned to control levels after 96 h of recovery. In addition, malondialdehyde levels were increased in treatment groups compared with the control and did not return to control levels even after a recovery period, indicating that ILs induced lipid peroxidation in snail viscera. These results suggest that oxidative stress and lipid peroxidation may be involved in the mechanism of toxicity for ILs. PMID:24497176

Ma, Junguo; Dong, Xiangyi; Fang, Qian; Li, Xiaoyu; Wang, Jianji

2014-02-01

354

High molecular weight lectin isolated from the mucus of the giant African snail Achatina fulica.  

PubMed

To understand better the host defense mechanisms of mollusks against pathogens, we examined the anti-microbial activity of mucus from the giant African snail Achatina fulica. Hemagglutination activity of the mucus secreted by the integument of snails inoculated with Escherichia coli was observed to increase and to cause hemagglutination of rabbit red blood cells. Purification of the snail mucus lectin by sequential column chromatography revealed that the relative molecular mass of the lectin was 350 kDa. The hemagglutination activity of the lectin was Ca(2+)-dependent and was inhibited by galactose. Growth arrest tests showed that the lectin did not inhibit bacterial growth, but did induce agglutination of gram-positive and gram-negative bacteria. Tissue distribution analyses using a polyclonal antibody revealed that the lectin was expressed in the tissues of the mantle collar. The lectin isolated from the mucus of the snail appeared to contribute to its innate immunity. PMID:21228483

Ito, Shigeru; Shimizu, Masahiro; Nagatsuka, Maki; Kitajima, Seiji; Honda, Michiyo; Tsuchiya, Takahide; Kanzawa, Nobuyuki

2011-01-01

355

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

PubMed Central

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

Deheyn, Dimitri D.; Wilson, Nerida G.

2011-01-01

356

Oil, Beer, and Snails -Sustainable Forest Management Means More than Just Wood JUL 20 2010 | ITALY  

E-print Network

factor supporting the income of forest owners and the welfare of rural populations in such marginal areas 'protoccle'), Pliny (who thought that the snail increased the speed of child delivery and was "a sovereign

357

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

PubMed Central

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

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

2014-01-01

358

Effects of eutrophication and snails on Eurasian watermilfoil (Myriophyllum spicatum) invasion  

E-print Network

Effects of eutrophication and snails on Eurasian watermilfoil (Myriophyllum spicatum) invasion; accepted in revised form 10 October 2005 Key words: eutrophication, food web, invasive species) run- off, which causes eutrophication. Eutrophication has a myriad of negative consequences, including

359

THE BIOCIDE TRIBUTYLTIN ALTERS TESTOSTERONE ESTERIFICATION IN MUD SNAILS (ILYANASSA OBSOLETA)  

EPA Science Inventory

The Biocide Tributyltin Alters Testosterone Esterification in Mud Snails (Ilyanassa obsoleta) Meredith P. Gooding and Gerald A. LeBlanc Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695-7633 Tributyltin (TBT...

360

Survey of Angiostrongylus cantonensis in rats and giant African land snails in Phitsanulok province, Thailand  

Microsoft Academic Search

ObjectiveTo survey the Angiostrongylus cantonensis (A. cantonensis) or the rat lungworm in a rat, definitive host, and in a giant African land snail (Achatina fulica), the intermediate host, in Phitsanulok, Thailand.

Apichat Vitta; Raxsina polseela; Seangchai Nateeworanart; Muncharee Tattiyapong

2011-01-01

361

Proteomic profile of Bithynia siamensis goniomphalos snails upon infection with the carcinogenic liver fluke Opisthorchis viverrini  

E-print Network

parasite infections [16-19], and snail lectins and opsonins 91 have also been shown to impact on trematode infections [20-23]. 92 93 The biological interactions between trematodes and their intermediate hosts are 94 crucial events that determine...

Prasopdee, Sattrachai; Tesana, Smarn; Cantacessi, Cinzia; Laha, Thewarach; Mulvenna, Jason; Grams, Rudi; Loukas, Alex; Gallego, Javier Sotillo

2014-10-02

362

Bioaccumulative and conchological assessment of heavy metal transfer in a soil-plant-snail food chain  

PubMed Central

Background Copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) can pose serious threats to environmental health because they tend to bioaccumulate in terrestrial ecosystems. We investigated under field conditions the transfer of these heavy metals in a soil-plant-snail food chain in Banat area, Romania. The main goal of this paper was to assess the Roman snail (Helix pomatia) usefulness in environmental monitoring as bioindicator of heavy metal accumulation. Eight sampling sites, selected by different history of heavy metal (HM) exposure, were chosen to be sampled for soil, nettle leaves, and newly matured snails. This study also aimed to identify the putative effects of HM accumulation in the environment on phenotypic variability in selected shell features, which included shell height (SH), relative shell height (RSH), and whorl number (WN). Results Significantly higher amounts of HMs were accumulated in snail hepatopancreas and not in foot. Cu, Zn, and Cd have biomagnified in the snail body, particularly in the hepatopancreas. In contrast, Pb decreased when going up into the food chain. Zn, Cd, and Pb correlated highly with each other at all levels of the investigated food chain. Zn and Pb exhibited an effective soil–plant transfer, whereas in the snail body only foot Cu concentration was correlated with that in soil. There were significant differences among sampling sites for WN, SH, and RSH when compared with reference snails. WN was strongly correlated with Cd and Pb concentrations in nettle leaves but not with Cu and Zn. SH was independent of HM concentrations in soil, snail hepatopancreas, and foot. However, SH correlated negatively with nettle leaves concentrations for each HM except Cu. In contrast, RSH correlated significantly only with Pb concentration in hepatopancreas. Conclusions The snail hepatopancreas accumulates high amounts of HMs, and therefore, this organ can function as a reliable biomarker for tracking HM bioavailability in soil. Long-term exposure to HMs via contaminated food might influence the variability of shell traits in snail populations. Therefore, our results highlight the Roman snail (Helix pomatia) potential to be used in environmental monitoring studies as bioindicator of HM pollution. PMID:22703871

2012-01-01

363

Pesticide concentrations in snail kite eggs and nestlings in Florida  

USGS Publications Warehouse

From 1970-1977, unhatched snail kite eggs and young that were found dead at nests in Florida were analyzed by gas chromatography for residues of organochlorine pollutants. The 1970 and 1974 material showed measurable amounts of p,p'-DDE, p,p'-DDD, p,p'-DDT, and dieldrin. Dieldrin and polychlorinated biphenyl (PCB) residues were less than 0.1 ppm in the eggs and were detected in only one sample of muscle tissue at 0.11 ppm. Concentrations in ppm wet weight of p,p'-DDE, p,p' DDD, p,p'-DDT, dieldrin, and PCB for two samples of muscle and three of brain tissue (all 1977 material) were not detected at the limit of quantification (0.05 ppm).

Sykes, P.W., Jr.

1985-01-01

364

The Epithelial-Mesenchymal Transition Factor SNAIL Paradoxically Enhances Reprogramming  

PubMed Central

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

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

2014-01-01

365

Copper toxicity to the fresh water snail, Lymnaea luteola  

SciTech Connect

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

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

1987-07-01

366

Solar radio-transmitters on snail kites in Florida  

USGS Publications Warehouse

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

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

1989-01-01

367

Associative learning phenomena in the snail (Helix aspersa): conditioned inhibition.  

PubMed

Two experiments using garden snails (Helix aspersa) showed conditioned inhibition using both retardation and summation tests. Conditioned inhibition is a procedure by which a stimulus becomes a predictor of the absence of a relevant event--the unconditioned stimulus (US). Typically, conditioned inhibition consists of pairings between an initially neutral conditioned stimulus, CS(2), and an effective excitatory conditioned stimulus, CS(1), in the absence of the US. Retardation and summation tests are required in order to confirm that CS(2) has acquired inhibitory properties. Conditioned inhibition has previously been found in invertebrates; however, these demonstrations did not use the retardation and summation tests required for an unambiguous demonstration of inhibition, allowing for alternative explanations. The implications of our results for the fields of comparative cognition and invertebrate physiological models of learning are discussed. PMID:21877176

Acebes, Félix; Solar, Patricia; Moris, Joaquín; Loy, Ignacio

2012-03-01

368

[Occurrence of Achatina fulica Bowdich, 1822 (Mollusca, Gastropoda) in Brazil: intermediate snail host of angiostrongyliasis].  

PubMed

Achatina fulica, the intermediate snail host of angiostrongyliasis and also an agricultural pest, is being bred in Brazil for human consumption as "escargot". The snail has escaped from its artificial breeding sites and its dispersal in Itariri country, State of S. Paulo, is reported here for the first time. A. fulica is a transmitter of the rat lungworm Angiostrongylus cantonensis, nematode which causes meningoencephalic angiostrongyliasis; the risks of human contamination are commented on. PMID:9515269

Teles, H M; Vaz, J F; Fontes, L R; Domingos, M de F

1997-06-01

369

Refuge function of marine algae complicates selection in an intertidal snail  

Microsoft Academic Search

Species with restricted gene flow often show trait-shifts from one type of environment to another. In those rock-dwelling marine gastropods that lack larval dispersal, size generally decreases in wave-exposed habitats reducing risk of dislodgement, while increases in less exposed habitats to resist crab-crushing. In Littorina fabalis, however, snails of moderately exposed shores are generally much larger (11–14 mm) than snails of

Petri Kemppainen; Solveig van Nes; Christofer Ceder; Kerstin Johannesson

2005-01-01

370

Expression of transcription factors snail, slug, and twist in human bladder carcinoma  

Microsoft Academic Search

BACKGROUND: Slug, Snail, and Twist are transcription factors that regulate the expression of tumor suppressors such as E-cadherin. In this study, we aimed to examine the expression of these transcription factors in human bladder carcinoma. METHODS: We first investigated expression of Slug, Snail, Twist and E-cadherin in five bladder Carcinoma cell lines by reverse transcription-polymerase chain reaction and western blotting.

Qinchao Yu; Kejun Zhang; Xinsheng Wang; Xiangping Liu; Zemi Zhang

2010-01-01

371

The effects of wetland habitat structure on Florida apple snail density  

USGS Publications Warehouse

Wetlands often support a variety of juxtaposed habitat patches (e.g., grass-, shrub- or tree-dominated) differentially suited to support the inhabiting fauna. The proportion of available habitat types has been affected by human activity and consequently has contributed to degrading habitat quality for some species. The Florida apple snail (Pomacea paludosa) has drawn attention as a critical prey item for wetlands wildlife and as an indicator of wetlands restoration success in peninsular Florida, USA. An apparent contradiction has evolved wherein this species appears intolerant of drying events, but these disturbances may be necessary to maintain suitable habitat structure for apple snails. We recently reported that assertions regarding intolerance to dry downs in this species were inaccurate. Here, we compared snail density in habitats with (wet prairie) and without (slough) emergent macrophytes, as well as evaluating the effects of structural attributes within the broad wet prairie habitat type. Snail densities were greater in prairies relative to sloughs (??2= 12.90, df=1, P=0.0003), often by a factor of two to three. Within wet prairie habitats, we found greater snail densities in Panicum hemitomon as compared to Eleocharis cellulosa (??2=31.45, df=1, P=0.0001). Significantly fewer snails were found in dense E. cellulosa as compared to habitats with lower stem density (??2= 10.73, df=1, P=0.011). Our results indicate that wet prairie habitat supports greater snail densities than nymphaea-dominatd slough. Our results have implications for wetlands water management in that continuous inundation has been shown to convert wet prairie to slough habitat, and we suggest this should be avoided in support of apple snails and their predators. ?? 2006, The Society of Wetland Scientists.

Karunaratne, L.B.; Darby, P.C.; Bennetts, R.E.

2006-01-01

372

Shading decreases the abundance of the herbivorous California horn snail, Cerithidea californica  

USGS Publications Warehouse

Most of the intertidal zone in estuaries of California, USA and Baja California, Mexico is covered with vascular vegetation. Shading by these vascular plants influences abiotic and biotic processes that shape benthic community assemblages. We present data on the effects of shading on the California horn snail, Cerithidea californica. This species is important because it is the most common benthic macrofaunal species in these systems and acts as an obligate intermediate host of several species of rematode parasites that infect several other species. Using observational and experimental studies, we found a negative effect of shade on the distribution and abundance of the California horn snail. We hypothesized that shading reduces the abundance of the epipelic diatoms that the snails feeds on, causing snails to leave haded areas. We observed a negative relationship between vascular plant cover, sub-canopy light levels, and snail density in Mugu Lagoon. Then we experimentally manipulated light regimes, by clipping vegetation and adding shade structures, and found higher snail densities at higher light levels. In Goleta Slough, we isolated the effect of shade from vegetation by documenting a negative relationship between the shade created by two bridges and diatom and snail densities. We also found that snails moved the greatest distances over shaded channel banks compared to unshaded channel banks. Further, we documented the effect of water depth and channel bank orientation on shading in this system. An additional effect of shading is the reduction of temperature, providing an alternative explanation for some of our results. These results broaden our knowledge of how variation in the light environment influences the ecology of estuarine ecosystems.

Lorda, Julio; Lafferty, Kevin D.

2012-01-01

373

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

NASA Astrophysics Data System (ADS)

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

Verbitskaya, Olga; Manukovsky, Nickolay; Kovalev, Vladimir

374

Novel Snail1 Target Proteins in Human Colon Cancer Identified by Proteomic Analysis  

Microsoft Academic Search

BackgroundThe transcription factor Snail1 induces epithelial-to-mesenchymal transition (EMT), a process responsible for the acquisition of invasiveness during tumorigenesis. Several transcriptomic studies have reported Snail1-regulated genes in different cell types, many of them involved in cell adhesion. However, only a few studies have used proteomics as a tool for the characterization of proteins mediating EMT.Methodology\\/Principal FindingsWe identified by proteomic analysis using

María Jesús Larriba; Juan Casado-Vela; Natalia Pendás-Franco; Raúl Peña; Antonio García de Herreros; María Teresa Berciano; Miguel Lafarga; J. Ignacio Casal; Alberto Muñoz; Juan Valcarcel

2010-01-01

375

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

PubMed

The centrality of the transcriptional regulator Snail in epithelial-to-mesenchymal transformation (EMT), known to occur in models of diabetic nephropathy, has not been established. Transforming growth factor beta-1 (TGFbeta1) is induced in diabetic nephropathy and induces both Snail and EMT. Hypoxia inducible factors (HIFs) are known to induce Snail, independent of TGFbeta1. Notch induction is integral to Snail induction and EMT in tumour cells, but its role in the kidney is unknown. The present study was undertaken to determine the upstream regulators of Snail in the kidney in high glucose and hypoxic conditions. HK-2 cells were cultured in normoxic, hypoxic, high glucose and combined hypoxic/high glucose conditions. The expression of HIF1alpha, NotchIC, Snail, Lysyl oxidase-like 2 (Loxl2), and Hairy and Enhancer Split-1 (Hes1) were measured. We found that hypoxia increased HIF1alpha expression; however, concurrent exposure to high glucose blunted this effect. A similar pattern was observed in Lox12 expression, suggesting that Loxl2 was downstream of HIF1alpha, which was confirmed using siRNA techniques. Snail was upregulated by hypoxia and high glucose and in combination the effect was additive, suggesting independent upstream activation pathways by the two stimuli. Hes1 was upregulated by high glucose and to a lesser extent by hypoxia, but the effect of the combined stimuli was no greater than that observed with high glucose alone. NotchIC was downregulated by both hypoxia and high glucose, and in combination the effect was additive. Therefore, this study suggests that hypoxia and high glucose induce Snail expression through distinct pathways, independent of Notch signalling. PMID:20620220

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

2010-10-01

376

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

PubMed Central

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

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

2012-01-01

377

Molecular identification of first putative aquaporins in snails.  

PubMed

Aquaporins (AQPs), also known as water channel proteins, are members of a large protein family termed Major Intrinsic Proteins (MIP). The mammalian AQPs have been most comprehensively described, while knowledge about AQPs in invertebrates is limited mainly to insects. Not a single AQP protein has been described in snails to date. Consequently, we decided to search for the proteins in gastropod representatives, namely Lymnaea stagnalis, Catascopia occulta, and Stagnicola palustris (Mollusca; Gastropoda; Pulmonata; Lymnaeidae). Using the molecular approach, we identified L. stagnalis, C. occulta, and S. palustris open reading frames (ORFs) showing homology to AQP genes available in GenBank database, and characterized the encoded proteins, referred to as LsAQP1, CoAQP1, and SpAQP1, respectively. The putative snail aquaporins contain 299 amino acids, have a molecular mass of about 32 kDa, display the general AQP topology and three-dimensional structure congruent with orthodox AQPs, i.e., water-specific ones. Due to high levels of similarity in their characteristics, LsAQP1 was chosen for further studies, as the obtained results were supposed to be applicable for CoAQP1 and SpAQP1. Expression analysis revealed the presence of LsAQP1 transcript in the digestive tract, the cerebral ganglia, the kidney, the reproductive system, and the foot, suggesting that LsAQP1 as well as CoAQP1 and SpAQP1 are ubiquitous proteins and may play important roles in many essential water transport processes. The role appears to be confirmed by results of the yeast growth complementation assay pointing at functionality of LsAQP1. Thus, the obtained results support the AQP expression in gastropod tissues for the first time. PMID:24445747

Pie?kowska, Joanna R; Kosicka, Ewa; Wojtkowska, Ma?gorzata; Kmita, Hanna; Lesicki, Andrzej

2014-03-01

378

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

PubMed Central

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

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

2013-01-01

379

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

PubMed

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

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

2015-02-15

380

Doxorubicin enhances Snail/LSD1-mediated PTEN suppression in a PARP1-dependent manner.  

PubMed

The transcription factor Snail not only functions as a master regulator of epithelial-mesenchymal transition (EMT), but also mediates cell proliferation and survival. While previous studies have showed that Snail protects tumor cells from apoptosis through transcriptional repression of PTEN, the specific mechanism remains unclear. In this study, we demonstrated that Snail cooperates with LSD1 to repress PTEN in a PARP1-dependent manner. Upon doxorubicin treatment, Snail becomes tightly associated with PARP1 through its pADPr-binding motif and is subject to poly(ADP-ribosyl)ation. This modification can enhance Snail-LSD1 interaction and promote the recruitment of LSD1 to PTEN promoter, where LSD1 removes methylation on histone H3 lysine 4 for transcription repression. Furthermore, treatment of tumor cells with PARP1 inhibitor AZD2281 can compromise doxorubicin-induced PTEN suppression and enhance the inhibitory effect of doxorubicin. Together, we proposed a tentative drug-resistant mechanism through which tumor cells defend themselves against DNA damage-induced apoptosis. PARP1 inhibitors in combination with DNA damaging reagents might represent a promising treatment strategy targeting tumors with over-activated Snail and LSD1. PMID:24675890

Lin, Yiwei; Kang, Tiebang; Zhou, Binhua P

2014-01-01

381

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

PubMed

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

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

2012-12-01

382

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

PubMed Central

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

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

2012-01-01

383

Small mammals cause non-trophic effects on habitat and associated snails in a native system.  

PubMed

Legacy effects occur when particular species or their interactions with others have long-lasting impacts, and they are increasingly recognized as important determinants of ecological processes. However, when such legacy effects have been explicitly explored, they most often involve the long-term direct effects of species on systems, as opposed to the indirect effects. Here, we explore how a legacy of small mammal exclusion on the abundance of a shrub, bush lupine (Lupinus arboreus), influences the abundance of a native land snail (Helminthoglypta arrosa) in coastal prairie and dune habitats in central California. The factors that limit populations of land snails are very poorly known despite the threats to the persistence of this group of species. In grasslands, prior vole (Microtus californicus) exclusion created long-lasting gains in bush lupine abundance, mediated through the seedbank, and was associated with increased snail numbers (10×) compared to control plots where mammals were never excluded. Similar plots in dune habitat showed no difference in snail numbers due to previous mammal exclusion. We tested whether increased competition for food, increased predation, and/or lower desiccation explained the decline in snail numbers in plots with reduced lupine cover. Tethering experiments supported the hypothesis that voles can have long-lasting impacts as ecosystem engineers, reducing woody lupine habitat required for successful aestivation by snails. These results add to a growing list of studies that have found that non-trophic interactions can be limiting to invertebrate consumers. PMID:21691854

Huntzinger, Mikaela; Karban, Richard; Maron, John L

2011-12-01

384

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

385

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

PubMed

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

McKindsey, C W; McLaughlin, J D

1995-08-01

386

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

PubMed Central

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

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

2006-01-01

387

A repetitive DNA probe for the sensitive detection of Fasciola hepatica infected snails.  

PubMed

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 previously unavailable. We have cloned and sequenced a 124 bp fragment of repetitive DNA from F. hepatica which hybridizes specifically with DNA of F. hepatica but not with DNA of its snail intermediate hosts Fossaria cubensis and Pseudosuccinea columella, or with DNA of Fascioloides magna and Paramphistomum liorchis, ruminant trematodes which share the same intermediate host and same enzootic range as F. hepatica. Using this 124 bp fragment as a probe, infection in snails was detected immediately following miracidial penetration, thus a sensitivity equivalent to the minimum biologic unit of the parasite was achieved. This 124 bp repeated sequence belongs to a large family of 124 bp repeats that share a high level of sequence identity and constitute approximately 15% of the F. hepatica genome. We also report here the development of a quick and inexpensive DNA extraction protocol for use in field-collected snails. Thus, we have developed both a highly sensitive and specific DNA probe and a means to use the probe in a large epizootiologic study of F. hepatica where thousands of field-collected snails need to be assayed for infection. PMID:7635638

Kaplan, R M; Dame, J B; Reddy, G R; Courtney, C H

1995-05-01

388

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

PubMed

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

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

2001-07-01

389

Foraging and refuge use by a pond snail: Effects of physiological state, predators, and resources  

NASA Astrophysics Data System (ADS)

The costs and benefits of anti-predator behavioral responses should be functions of the actual risk of predation, the availability of the prey's resources, and the physiological state of the prey. For example, a food-stressed individual risks starvation when hiding from predators, while a well-fed organism can better afford to hide (and pay the cost of not foraging). Similarly, the benefits of resource acquisition are probably highest for the prey in the poorest state, while there may be diminishing returns for prey nearing satiation. Empirical studies of state-dependent behavior are only beginning, however, and few studies have investigated interactions between all three potentially important factors. Here I present the results of a laboratory experiment where I manipulated the physiological state of pond snails ( Physa gyrina), the abundance of algal resources, and predation cues ( Belostoma flumineum waterbugs consuming snails) in a full factorial design to assess their direct effects on snail behavior and indirect effects on algal biomass. On average, snails foraged more when resources were abundant, and when predators were absent. Snails also foraged more when previously exposed to physiological stress. Snails spent more time at the water's surface (a refuging behavior) in the presence of predation cues on average, but predation, resource levels, and prey state had interactive effects on refuge use. There was a consistent positive trait-mediated indirect effect of predators on algal biomass, across all resource levels and prey states.

Wojdak, Jeremy M.

2009-09-01

390

The biocide tributyltin reduces the accumulation of testosterone as fatty acid esters in the mud snail (Ilyanassa obsoleta).  

PubMed Central

Imposex, the development of male sex characteristics by female gonochoristic snails, has been documented globally and is causally associated with exposure to the ubiquitous environmental contaminant tributyltin (TBT). Elevated testosterone levels in snails also are associated with TBT, and direct exposure to testosterone has been shown to cause imposex. We discovered previously that the mud snail (Ilyanassa obsoleta)biotransforms and retains excess testosterone primarily as fatty acid esters. The purpose of this study was to determine whether TBT interferes with the esterification of testosterone, resulting in the elevated free (unesterified) testosterone levels associated with imposex. Exposure of snails to environmentally relevant concentrations of TBT (> or = 1.0 ng/L as tin) significantly increased the incidence of imposex. Total (free + esterified) testosterone levels in snails were not altered by TBT; however, free testosterone levels increased with increasing exposure concentration of TBT. TBT-exposed snails were given [14C

Gooding, Meredith P; Wilson, Vickie S; Folmar, Leroy C; Marcovich, Dragoslav T; LeBlanc, Gerald A

2003-01-01

391

WWamide-1, -2 and -3: novel neuromodulatory peptides isolated from ganglia of the African giant snail, Achatina fulica.  

PubMed

Three novel neuropeptides, isolated from ganglia of the African giant snail, Achatina fulica, were named WWamide-1, -2 and -3. These substances were biologically active heptapeptide amides with a Trp residue at both the N- and C-termini. WWamide-1, which displayed an inhibitory activity on a central neuron of the snail, exhibited peripherally modulatory effects on muscular contractions of not only the gut and other tissues of the snail but also certain tissues of other molluscs. PMID:8495720

Minakata, H; Ikeda, T; Muneoka, Y; Kobayashi, M; Nomoto, K

1993-05-24

392

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

393

The effect of life-history variation on the population size structure of a rocky intertidal snail ( Littorina sitkana)  

Microsoft Academic Search

On wave-sheltered shores of the northeastern Pacific, the population size structure of Littorina sitkana varies with intertidal height, as larger snails are mostly found only in the upper intertidal. This pattern has been attributed to high predation rates by crabs (and perhaps fish) on large snails inhabiting low-intertidal areas; i.e., large snails are presumed to be rare there simply because

Rémy Rochette; Karen Dunmall; Lawrence M. Dill

2003-01-01

394

[Occurrence of the flagellated protozoan, Cryptobia helicis Leidy, 1846 (Kinetoplasta: Bodonea: Cryptobiidae) in the garden snail, Helix aspersa].  

PubMed

In this survey, the prevalence and cytological features of the flagellated protozoan, Cryptobia helicis living in the bursa copulatrix of the garden snail, Helix aspersa Müller 1774 found in the vicinity of Izmir, Turkey was investigated. The prevalence of Cryptobia helicis in garden snails collected in the spring of 2005 was found to be 68.65%. This study is the first record of the occurrence of Cryptobia helicis in the garden snail Helix aspersa found in Turkey. PMID:18351561

Göçmen, Bayram; Gürelli, Gözde

2008-01-01

395

The detection and quantification of a digenean infection in the snail host with special emphasis on Fasciola sp  

Microsoft Academic Search

In this review, ten methods used to study digenean infections in their intermediate hosts were compared to determine which\\u000a one should be used either in the field or in the lab to establish the prevalence and intensity of infections in snails. Snail\\u000a crushing and snail dissection allow quick establishing of prevalence in natural or experimental infections, whereas histology\\u000a is considered

Yannick Caron; Daniel Rondelaud; Bertrand Losson

2008-01-01

396

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

PubMed Central

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

Yeung, Norine W; Hayes, Kenneth A

2013-01-01

397

Effects of washing produce contaminated with the snail and slug hosts of Angiostrongylus cantonensis with three common household solutions.  

PubMed

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

Yeung, Norine W; Hayes, Kenneth A; Cowie, Robert H

2013-06-01

398

FBXO11 promotes ubiquitination of the Snail family of transcription factors in cancer progression and epidermal development.  

PubMed

The Snail family of transcription factors are core inducers of epithelial-to-mesenchymal transition (EMT). Here we show that the F-box protein FBXO11 recognizes and promotes ubiquitin-mediated degradation of multiple Snail family members including Scratch. The association between FBXO11 and Snai1 in vitro is independent of Snai1 phosphorylation. Overexpression of FBXO11 in mesenchymal cells reduces Snail protein abundance and cellular invasiveness. Conversely, depletion of endogenous FBXO11 in epithelial cancer cells causes Snail protein accumulation, EMT, and tumor invasion, as well as loss of estrogen receptor expression in breast cancer cells. Expression of FBXO11 is downregulated by EMT-inducing signals TGF? and nickel. In human cancer, high FBXO11 levels correlate with expression of epithelial markers and favorable prognosis. The results suggest that FBXO11 sustains the epithelial state and inhibits cancer progression. Inactivation of FBXO11 in mice leads to neonatal lethality, epidermal thickening, and increased Snail protein levels in epidermis, validating that FBXO11 is a physiological ubiquitin ligase of Snail. Moreover, in C. elegans, the FBXO11 mutant phenotype is attributed to the Snail factors as it is suppressed by inactivation/depletion of Snail homologs. Collectively, these findings suggest that the FBXO11-Snail regulatory axis is evolutionarily conserved and critically governs carcinoma progression and mammalian epidermal development. PMID:25827072

Jin, Yue; Shenoy, Anitha K; Doernberg, Samuel; Chen, Hao; Luo, Huacheng; Shen, Huangxuan; Lin, Tong; Tarrash, Miriam; Cai, Qingsong; Hu, Xin; Fiske, Ryan; Chen, Ting; Wu, Lizi; Mohammed, Kamal A; Rottiers, Veerle; Lee, Siu Sylvia; Lu, Jianrong

2015-06-28

399

Inhibition of Snail1-DNA-PKcs Protein-Protein Interface Sensitizes Cancer Cells and Inhibits Tumor Metastasis*  

PubMed Central

Our previous study suggested that the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) interacts with Snail1, which affects genomic instability, sensitivity to DNA-damaging agents, and migration of tumor cells by reciprocal regulation between DNA-PKcs and Snail1. Here, we further investigate that a peptide containing 7-amino acid sequences (amino acids 15–21) of Snail1 (KPNYSEL, SP) inhibits the endogenous interaction between DNA-PKcs and Snail1 through primary interaction with DNA-PKcs. SP restored the inhibited DNA-PKcs repair activity and downstream pathways. On the other hand, DNA-PKcs-mediated phosphorylation of Snail1 was inhibited by SP, which resulted in decreased Snail1 stability and Snail1 functions. However, these phenomena were only shown in p53 wild-type cells, not in p53-defective cells. From these results, it is suggested that interfering with the protein interaction between DNA-PKcs and Snail1 might be an effective strategy for sensitizing cancer cells and inhibiting tumor migration, especially in both Snail1-overexpressing and DNA-PKcs-overexpressing cancer cells with functional p53. PMID:24085291

Kang, Ga-Young; Pyun, Bo-Jeong; Seo, Haeng Ran; Jin, Yeung Bae; Lee, Hae-June; Lee, Yoon-Jin; Lee, Yun-Sil

2013-01-01

400

Changes in epilithic communities due to individual and combined treatments of zinc and snail grazing in stream mesocosms  

SciTech Connect

Effects of 0.5 mg/liter zinc (Zn) and snail grazing (400 snails/m2) on density of dominant algal and protozoan taxa, epilithic glucose respiration, and ash-free dry weight (AFDW) were examined using established (12-day colonization) periphyton communities in flow-through stream mesocosms with four treatments (Zn, snails, Zn and snails, control) for 30 days. Grazing and Zn similarly reduced the abundance of 5 of 10 dominant algal taxa and AFDW during the first 10 days of treatment. Abundance of these taxa and AFDW in grazed (ambient Zn) treatments approached control levels after 10 days as the effect due to snails decreased. Decreasing temperatures may have reduced snail activity. Snails, Zn, and the combination of these treatments contributed to higher rates of glucose respiration per unit AFDW. Protozoan species abundance was reduced to less than half by Zn but was unaffected by snails. Although Zn and snails individually altered structural and functional aspects of this microbial community, the effects when both treatments were combined could not always be inferred from the individual effects. Testing individual and combined variables that affect periphyton with a corresponding assessment of population dynamics, biomass, and community functional attributes will enhance understanding of the overall effects of pollutants on periphyton communities.

Genter, R.B.; Colwell, F.S.; Pratt, J.R.; Cherry, D.S.; Cairns, J. Jr.

1988-06-01

401

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

PubMed

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

Zotin, A A; Ozerniuk, N D

2002-01-01

402

Release of Lungworm Larvae from Snails in the Environment: Potential for Alternative Transmission Pathways  

PubMed Central

Background Gastropod-borne parasites may cause debilitating clinical conditions in animals and humans following the consumption of infected intermediate or paratenic hosts. However, the ingestion of fresh vegetables contaminated by snail mucus and/or water has also been proposed as a source of the infection for some zoonotic metastrongyloids (e.g., Angiostrongylus cantonensis). In the meantime, the feline lungworms Aelurostrongylus abstrusus and Troglostrongylus brevior are increasingly spreading among cat populations, along with their gastropod intermediate hosts. The aim of this study was to assess the potential of alternative transmission pathways for A. abstrusus and T. brevior L3 via the mucus of infected Helix aspersa snails and the water where gastropods died. In addition, the histological examination of snail specimens provided information on the larval localization and inflammatory reactions in the intermediate host. Methodology/Principal Findings Twenty-four specimens of H. aspersa received ~500 L1 of A. abstrusus and T. brevior, and were assigned to six study groups. Snails were subjected to different mechanical and chemical stimuli throughout 20 days in order to elicit the production of mucus. At the end of the study, gastropods were submerged in tap water and the sediment was observed for lungworm larvae for three consecutive days. Finally, snails were artificially digested and recovered larvae were counted and morphologically and molecularly identified. The anatomical localization of A. abstrusus and T. brevior larvae within snail tissues was investigated by histology. L3 were detected in the snail mucus (i.e., 37 A. abstrusus and 19 T. brevior) and in the sediment of submerged specimens (172 A. abstrusus and 39 T. brevior). Following the artificial digestion of H. aspersa snails, a mean number of 127.8 A. abstrusus and 60.3 T. brevior larvae were recovered. The number of snail sections positive for A. abstrusus was higher than those for T. brevior. Conclusions Results of this study indicate that A. abstrusus and T. brevior infective L3 are shed in the mucus of H. aspersa or in water where infected gastropods had died submerged. Both elimination pathways may represent alternative route(s) of environmental contamination and source of the infection for these nematodes under field conditions and may significantly affect the epidemiology of feline lungworms. Considering that snails may act as intermediate hosts for other metastrongyloid species, the environmental contamination by mucus-released larvae is discussed in a broader context. PMID:25884402

Giannelli, Alessio; Colella, Vito; Abramo, Francesca; do Nascimento Ramos, Rafael Antonio; Falsone, Luigi; Brianti, Emanuele; Varcasia, Antonio; Dantas-Torres, Filipe; Knaus, Martin; Fox, Mark T.; Otranto, Domenico

2015-01-01

403

Distribution of trematodes in snails in ponds at integrated small-scale aquaculture farms.  

PubMed

In integrated small-scale aquaculture farming, animal and human excreta maybe used as fish feed and pond fertilizer, thereby enhancing transmission of fish-borne zoonotic trematodes (FZTs) from final hosts, like humans, pigs and chickens, to snails. Areas within a pond could vary in trematode egg-load due to the immediate bordering land, and this might provide implications for control of these trematodes or sampling in field studies measuring FZT prevalence in snails. We therefore estimated the effect of bordering land use on prevalence and FZT burden in snails in different areas within small-scale aquaculture ponds. Nine sampling areas within a pond were assigned in six ponds. For each sampling area, about 120 Melanoides tuberculata snails were collected. Based on land use bordering a sampling area, these were categorized in 5 risk-categories: low-risk (road, rice planted in pond, agriculture, or middle of pond), human access point to pond, livestock sty (pigs or poultry), both human access point and livestock sty, and water connection to canal. In total, 5392 snails were collected. Percentages of snails with parapleurolophocercous cercariae varied between 6% in areas categorized as low-risk and areas with livestock sty only to 15% in areas with both human access point and livestock sty; only this 15% was significantly different from the prevalence in the low-risk category. Percentages of snails with xiphidio cercariae did not differ between risk-categories and varied between 5% and 10%. Mean snail size was 15.2mm, and was significantly associated with both the probability of infection as well as parasite burden. Very small differences in parasite burden were found at different land use areas; the maximum difference was about 11 cercariae. This study demonstrated only small differences between areas surrounding a pond on risk of snails to be infected with fish-borne trematodes within different pond areas. In field studies on FZTs in M. tuberculata snails in ponds, sampling from ponds can therefore be done without considering areas within ponds. PMID:23200642

Boerlage, Annette S; Graat, Elisabeth A M; Verreth, Johan A; de Jong, Mart C M

2013-03-01

404

24 ENDANGERED SPECIES BULLETIN JANUARY/FEBRUARY 2003 VOLUME XXVIII NO. 1 Atiny snail, a relict from the last great ice age,  

E-print Network

in the leaf litter, preferring a diet of birch and maple leaves. The snail shares its habitat with a Shell snail found its current home with desirable temperature, moisture, and food resources about 10,000 years

Cochran-Stafira, D. Liane

405

Prehistoric inter-archipelago trading of Polynesian tree snails leaves a conservation legacy  

PubMed Central

Inter-archipelago exchange networks were an important aspect of prehistoric Polynesian societies. We report here a novel genetic characterization of a prehistoric exchange network involving an endemic Pacific island tree snail, Partula hyalina. It occurs in the Society (Tahiti only), Austral and Southern Cook Islands. Our genetic data, based on museum, captive and wild-caught samples, establish Tahiti as the source island. The source lineage is polymorphic in shell coloration and contains a second nominal species, the dark-shelled Partula clara, in addition to the white-shelled P. hyalina. Prehistoric inter-island introductions were non-random: they involved white-shelled snails only and were exclusively inter-archipelago in scope. Partulid shells were commonly used in regional Polynesian jewellery, and we propose that the white-shelled P. hyalina, originally restricted to Tahiti, had aesthetic value throughout these archipelagoes. Demand within the Society Islands could be best met by trading dead shells, but a low rate of inter-archipelago exchange may have prompted the establishment of multiple founder populations in the Australs and Southern Cooks. The alien carnivorous land snail Euglandina rosea has recently devastated populations of all 61 endemic species of Society Island partulid snails. Southern Cooks and Australs P. hyalina now represent the only unscathed wild populations remaining of this once spectacular land snail radiation. PMID:17848368

Lee, Taehwan; Burch, John B; Coote, Trevor; Fontaine, Benoît; Gargominy, Olivier; Pearce-Kelly, Paul; Foighil, Diarmaid Ó

2007-01-01

406

Snail-type zinc finger proteins prevent neurogenesis in Scutoid and transgenic animals of Drosophila.  

PubMed

Scutoid is a classical dominant gain-of-function mutation of Drosophila, causing a loss of bristles and roughening of the compound eye. Previous genetic and molecular analyses have shown that Scutoid is associated with a chromosomal transposition resulting in a fusion of no-oceli and snail genes. How this gene fusion event leads to the defects in neurogenesis was not known until now. Here have found that snail is ectopically expressed in the eye-antennal and wing imaginal discs in Scutoid larvae, and that this expression is reduced in Scutoid revertants. We have also shown that the expressivity of Scutoid is enhanced by zeste mutations. snail and escargot encode evolutionarily conserved zinc-finger proteins involved in the development of mesoderm and limbs. Snail and Escargot proteins share a common target DNA sequence with the basic helix-loop-helix (bHLH) type proneural gene products. When expressed in the developing external sense organ precursors of the thorax and the eye, these proteins cause a loss of mechanosensory bristles in the thorax and perturbed the development of the compound eye. Such phenotypes resemble those associated with Scutoid. Furthermore, the effect of ectopic Escargot on bristle development is antagonized by coexpression of the bHLH gene asense. Thus, our results suggest that the Scutoid phenotype is due to an ectopic snail expression under the control of no-oceli enhancer, antagonizing neurogenesis through its inhibitory interaction with bHLH proteins. PMID:10552298

Fuse, N; Matakatsu, H; Taniguchi, M; Hayashi, S

1999-10-01

407

The Drosophila gene escargot encodes a zinc finger motif found in snail-related genes.  

PubMed

Two independent P-element enhancer detection lines were obtained that express lacZ in a pattern of longitudinal stripes early in germband elongation. In this paper, molecular and genetic characterization of a gene located near these transposons is presented. Sequence analysis of a cDNA clone from the region reveals that this gene has a high degree of similarity with the Drosophila snail gene (Boulay et al., 1987). The sequence similarity extends over 400 nucleotides, and includes a region encoding five tandem zinc finger motifs (72% nucleotide identity; 76% amino acid identity). This region is also conserved in the snail homologue from Xenopus laevis (76% nucleotide identity; 83% amino acid identity) (Sargent and Bennett, 1990). We have named the Drosophila snail-related gene escargot (esg), and the region of sequence conservation common to all three genes the 'snailbox'. A number of Drosophila genomic DNA fragments cross-hybridize to a probe from the snailbox region suggesting that snail and escargot are members of a multigene family. The expression pattern of escargot is dynamic and complex. Early in germband elongation, escargot RNA is expressed in a pattern of longitudinal stripes identical to the one observed in the two enhancer detection lines. Later in development, escargot is expressed in cells that will form the larval imaginal tissues, escargot is allelic with l(2)35Ce, an essential gene located near snail in the genome. PMID:1571289

Whiteley, M; Noguchi, P D; Sensabaugh, S M; Odenwald, W F; Kassis, J A

1992-02-01

408

Fascioliasis control: in vivo and in vitro phytotherapy of vector snail to kill fasciola larva.  

PubMed

Snail is one of the important components of an aquatic ecosystem, it acts as intermediate host of Fasciola species. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. Life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria in the snail body. In vivo and in vitro toxicity of the plant products and their active component such as citral, ferulic acid, umbelliferone, azadirachtin, and allicin against larva of Fasciola in infected snail Lymnaea acuminata were tested. Mortality of larvae were observed at 2?h, 4?h, 6?h, and 8?h, of treatment. In in vivo treatment, azadirachtin caused highest mortality in redia and cercaria larva (8?h, LC(50) 0.11, and 0.05?mg/L) whereas in in vitro condition allicin was highly toxic against redia and cercaria (8?h, LC(50) 0.01, and 0.009?mg/L). Toxicity of citral was lowest against redia and cercaria larva. PMID:22132306

Sunita, Kumari; Singh, D K

2011-01-01

409

Transmission of Angiostrongylus cantonensis through the giant African snail Achatina fulica: an experimental study.  

PubMed

Observations on transmission of the rat lung worm, Angiostrongylus cantonensis, from rats to the snail intermediate host. Achatina fulica, in a vacant lot in Bangkok are described. The prevalence of A. cantonensis increased with snail age until 200 days of age when it attained a plateau of 50-60%. The overall prevalence was 53%. The worm burden slowly rose with age until 200 days of age beyond which it remained relatively constant. The highest mean worm burden of 5,478 was observed in the oldest age group. The parasite distribution in the snail population was highly aggregated both within each age class and in the overall population. Experiments on susceptibility of snails to laboratory infection revealed that worm recovery was dependent on dose of first stage larval infection but was independent of snail size in the range of 4-8 cm. The percent worm recovery of third stage larvae was negatively correlated with dose of infection, and no density-dependent effects of worm burden on worm size were observed. PMID:1822886

Sithithaworn, P; Brockelman, W Y; Brockelman, C

1991-12-01

410

Tales of two snails: sexual selection and sexual conflict in Lymnaea stagnalis and Helix aspersa.  

PubMed

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 dart increases sperm storage and paternity, probably via the transfer of an allohormone that inhibits sperm digestion. A recent interspecies comparison of dart-possessing land snails revealed coevolution between darts and spermatophore-receiving organs that is consistent with counteradaptation against an allohormonal manipulation. The great pond snail (Lymnaea stagnalis) seems to use a seminal product to manipulate its partner and mates in the male role when enough seminal fluid is available in the prostate gland. Receipt of semen not only initiates egg laying in virgin animals, but also feminizes the mating partner later in life. These increases in the female function have been shown to go at the expense of growth and seminal fluid production of the sperm recipient. Although in Helix, and probably also Lymnaea, the sperm donor benefits from the induced changes through increased fertilization success, the sperm recipient may experience injury, imposed reallocation of resources, and altered sperm storage. These findings support the existence of sexual conflict in simultaneously hermaphroditic snails, and its importance for the evolution of mating behaviors and reproductive morphologies is discussed. PMID:21672754

Koene, Joris M

2006-08-01

411

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

PubMed

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

Madsen, H; Hung, N M

2014-12-01

412

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

PubMed

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

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

2015-02-10

413

How subcellular partitioning can help to understand heavy metal accumulation and elimination kinetics in snails.  

PubMed

To understand bioaccumulation kinetics of metals within biota inhabiting industrially contaminated soils, toxicokinetic dynamics and subcellular fractionation were carried out with the terrestrial snail Helix aspersa in a long-term (six-month) laboratory experiment. Accumulation and elimination kinetics were determined for Cd, Pb, and Zn in both viscera and foot of snails and were described accurately by one-compartment models. The subcellular fractions were obtained by sequential centrifugations and were analyzed by isolating metal-rich granules, tissue fragments, and cytosolic fractions. Different fractions showed metal-specific binding capacities that might be useful in identifying the biological significance of accumulated metal levels in snails. Cadmium was retrieved mainly from the cytosolic fraction, where it was stored in the long term and not excreted, thus explaining the linear accumulation patterns. Most of the accumulated Pb was found in the granular fraction, and snails appeared able to excrete these concretions, leading to achievement of a steady state in internal Pb body burdens. Significant levels of Pb, however, were retrieved at the end of the depuration phase and retained in the cell debris fraction. Zinc showed affinities for both cytosolic and granular fractions, leading to intermediate uptake and excretion patterns. The dynamics of the different sequestration forms at the subcellular level support the observed kinetics of metal body burdens and, in association with the determination of uptake fluxes, allow precise assessment of metal accumulation in snails. PMID:18229974

Gimbert, Frédéric; Vijver, Martina G; Coeurdassier, Michaël; Scheifler, Renaud; Peijnenburg, Willie J G M; Badot, Pierre-Marie; de Vaufleury, Annette

2008-06-01

414

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

PubMed

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

Longley, Roger D

2011-10-01