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Sample records for freshwater pulmonate snail

  1. An evaluation of the interactions between freshwater pulmonate snail hosts of human schistosomes and macrophytes.

    PubMed

    Thomas, J D

    1987-03-25

    An account is given of a laboratory investigation designed to evaluate the extent to which the freshwater pulmonate snail Biomphalaria glabrata (Say) can utilize various species of aquatic plants, mainly macrophytes, when presented in the following forms over different time scales: normal plants; dried plant material; homogenized plant material in calcium alginate matrices; water-soluble filtrates of plant homogenates in the medium. The following propositions, derived from the theory of phased coevolution of components of the module consisting of the epiphytic bacteria, algae, snails and macrophytes, are evaluated on the basis of the present results and others including those obtained in this laboratory. That as the snails had become specialized to exploit surface communities of epiphytic algae, decaying plant material and dissolved organic matter (DOM) early in their evolutionary history they would continue to exploit these resources when they later become associated with aquatic macrophytes. That pulmonate snails would tend to be feeding generalists capable of adapting to food of varying chemical composition, given sufficient time, provided it was sufficiently small or flaccid. That although macrophytes and snails show a strong positive relationship, the living macrophyte tissue would be little used by the snails. That the hard outer envelope, inherited from their terrestrial ancestors, would remain as the major defence mechanism of aquatic macrophytes against attack by snails and other aquatic invertebrates. That aquatic macrophytes would invest little in the nutrient deficiency strategy to reduce attack by invertebrates such as snails. That truly aquatic submerged macrophytes would not possess secondary plant compounds (SPC) that would be molluscicidal. Emergent parts of subaquatic or aquatic plants might be expected to be better sources of SPC with molluscicidal factors than submerged aquatic plants. Species of epiphytic or planktonic algae might be better sources of SPC with molluscicidal effects than aquatic macrophytes. That the strategies developed by pulmonate snails for obtaining their energy supplies would not be conducive to rapid speciation. The analysis of the present and other related results supports these propositions. Predictions based on the theory of mutualism involving the snails, macrophytes and other components of the module also receive some support from an analysis of the present results. The additional empirical work that could be undertaken to test this theory is briefly discussed.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2883688

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

    PubMed

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

    2010-08-01

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

  3. An embryonic transcriptome of the pulmonate snail Radix balthica.

    PubMed

    Tills, Oliver; Truebano, Manuela; Rundle, Simon

    2015-12-01

    The pond snail, Radix balthica (Linnaeus 1758), is an emerging model species within ecological developmental biology. While its development has been characterised in detail, genomic resources for embryonic stages are lacking. We applied Illumina MiSeq RNA-seq to RNA isolated from pools of embryos at two points during development. Embryos were cultured in either the presence or absence of predator kariomones to increase the diversity of the transcripts assembled. Sequencing produced 47.2M paired-end reads, assembled into 54,360 contigs of which 73% were successfully annotated. This transcriptome provides an invaluable resource to build a mechanistic understanding of developmental plasticity. PMID:26297600

  4. The Heritability of Shell Morphometrics in the Freshwater Pulmonate Gastropod Physa

    PubMed Central

    Dillon, Robert T.; Jacquemin, Stephen J.

    2015-01-01

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

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

    PubMed

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

    2013-08-01

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

  6. The effects of the herbicide atrazine on freshwater snails.

    PubMed

    Gustafson, Kyle D; Belden, Jason B; Bolek, Matthew G

    2015-07-01

    Atrazine has been shown to affect freshwater snails from the subcellular to community level. However, most studies have used different snail species, methods, endpoints, and atrazine exposure concentrations, resulting in some conflicting results and limiting our understanding. The goal of this study was to address these concerns by (1) investigating the acute and chronic effects of atrazine on four species of freshwater snails (Biomphalaria glabrata, Helisoma trivolvis, Physa acuta, and Stagnicola elodes) using the same methods, endpoints, and concentrations, and (2) summarizing the current literature pertaining to the effects of atrazine on freshwater snails. We conducted a 48 h acute toxicity test with an atrazine concentration higher than what typically occurs in aquatic environments (1000 µg/L). Additionally, we exposed snails to environmentally relevant atrazine concentrations (0, 0.3, 3, and 30 µg/L) for 28 days and assessed snail survival, growth, and reproduction. We also summarized all known literature pertaining to atrazine effects on freshwater snails. The literature summary suggests snails are often affected by environmentally relevant atrazine concentrations at the subcellular and cellular levels. These effects are typically not transitive to effects on survival, growth, or reproduction at the same concentrations. Our acute exposures corroborate the general trend of no direct effect on snail populations as atrazine did not directly affect the survival of any of the four snail species. Similarly, environmentally relevant concentrations did not significantly affect the survival, growth, or reproduction of any snail species. These results indicate that, in the absence of other possible stressors, the direct effects of environmentally relevant atrazine concentrations may not be realized at the snail population level. PMID:25971234

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

    NASA Astrophysics Data System (ADS)

    Stott, Lowell D.

    2002-02-01

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

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

    PubMed

    Arendt, J

    2015-01-01

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

  9. Accelerated Mutation Accumulation in Asexual Lineages of a Freshwater Snail

    E-print Network

    Neiman, Maurine

    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

  10. FRESHWATER SNAILS (MOLLUSCA: GASTROPODA) OF NORTH AMERICA

    EPA Science Inventory

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

  11. The maintenance of hybrids by parasitism in a freshwater snail.

    PubMed

    Guttel, Yonathan; Ben-Ami, Frida

    2014-11-01

    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

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

    E-print Network

    Johnson, Steven G.

    The Effect of Aquatic Plant Abundance on Shell Crushing Resistance in a Freshwater Snail Johel matter that snails eat is related to the strength of their shells. We measured shell crushing resistance that can affect crushing resistance, such as the density of crushing predators, snail density, water p

  13. Multiple paternity in the freshwater snail, Potamopyrgus antipodarum

    PubMed Central

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

    2012-01-01

    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

  14. TREMATODE INFECTION OF FRESHWATER SNAIL, FAMILY BITHYNIIDAE IN THAILAND.

    PubMed

    Kulsantiwong, Jutharat; Prasopdee, Sattrachai; Piratae, Supawadee; Khampoosa, Panita; Thammasiri, Chalida; Suwannatrai, Apiporn; Boonmars, Thidarut; Viyanant, Vithoon; Ruangsitichai, Jiraporn; Tarbsripair, Pairat; Tesana, Smarn

    2015-05-01

    Opisthorchis viverrini is restricted to and requires for its aquatic life cycle only Bithynia snail as first intermediate host but many species of cyprinid fish as second intermediate hosts. A survey in Thailand of trematode infection in freshwater snails of the family Bithyniidae carried out during October 2008 - July 2009 found a total of 5,492 snails, classified into ten species distributed in various geographic areas. Bithyniafuniculata and Gabbia pygmaea were localized to the north, B. s. goniomphalos, Wattebledia siamensis and W. crosseana to northeast and B. s. siamensis, Hydrobioides nassa and G. wykoffi to central region. W. baschi and G. erawanensis was found only in the south and Erawan waterfall, Kanchanaburi Province, respectively. Trematode infection rate was 3.15%. Cercariae were identified as belonging to six types, namely, amartae , monostome, mutabile, O. viverrini, virgulate, and unknown. The prevalence of cercarial infection in B. s. goniomphalos of amartae, mutabile, O. viverrini, virgulate, and unknown type cercaria was 0.55%, 0.74%, 1.07%, 2.87%, and 0.37%, respectively, and in B. s. siamensis monostome (1.10%) and virgulate (0.55%). Only virgulate cercariae were shed from W. crosseana (3.85%) and W. siamensis (5.19%). Cercariae of the unknown type were found in G. wykoffi (1.69%). No infection of O. viverrini cercariae was detected in the other species. PMID:26521513

  15. Toxicity of Metals to a Freshwater Snail, Melanoides tuberculata

    PubMed Central

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

    2012-01-01

    Adult freshwater snails Melanoides tuberculata (Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT50) and concentrations (LC50) were calculated. LT50 and LC50 increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC50 values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59?mg?L?1, respectively. Cu was the most toxic metal to M. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration in M. tuberculata increases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC50 values for metals for this species with those for other freshwater gastropods reveals that M. tuberculata is equally sensitive to metals. PMID:22666089

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

    E-print Network

    Grosell, Martin

    Keywords: Gastropods Lymnaea stagnalis Copper Water quality criteria Ionoregulation Acid­base balance resulted in no detectable effects on hemolymph osmolality, net Ca2+ uptake, titratable acid excretion in titratable acid excretion. The reduction in net Ca2+ uptake was hypothesized to be a secondary effect of Cu

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

    PubMed Central

    Bartlett, K H; Trust, T J

    1976-01-01

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

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

    E-print Network

    Neiman, Maurine

    Response to Phosphorus Limitation Varies among Lake Populations of the Freshwater Snail. As an initial step to determining whether P. antipodarum are also locally adapted to phosphorus availability, we examined whether populations differ in their responses to phosphorus limitation. We found that field

  19. 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...

  20. Chemoreception of hunger levels alters the following behaviour of a freshwater snail.

    PubMed

    Larcher, Marie; Crane, Adam L

    2015-12-01

    Chemically-mediated orientation is essential for many animals that must locate sites containing resources such as mates or food. One way to find these areas is by using publically-available information from other individuals. We tested a freshwater snail, Physa gyrina, for chemoreception of conspecific cues and predicted they could discriminate between cues based on information regarding hunger levels. We placed 'tracker' snails into a 2-arm arena where they could either follow or avoid an area previously used by a 'marker' snail. The hunger levels of both trackers and markers was manipulated, being either starved or fed. Starved and fed trackers did not differ in their following response when markers were hungry, but starved trackers were significantly more likely to follow fed markers, compared to fed trackers that tended to avoid areas used by fed markers. This outcome suggests that P. gyrina uses conspecific chemical cues to find food and potentially in some situations to avoid intra-specific food competition. PMID:26478254

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

    NASA Technical Reports Server (NTRS)

    Gao, Wenyuan; Wiederhold, Michael; Hejl, Robert

    1997-01-01

    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.

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

    PubMed

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

    2013-11-01

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

  3. Control of schistosome-transmitting snails in Kenya by the North American crayfish Procambarus clarkii.

    PubMed

    Hofkin, B V; Mkoji, G M; Koech, D K; Loker, E S

    1991-09-01

    Snail-transmitted trematode parasites such as schistosomes and liver flukes assume considerable medical and veterinary significance in tropical Africa. We have observed a strong negative association between the presence of medically important pulmonate snails and the crayfish Procambarus clarkii in freshwater habitats in Kenya. This crayfish, introduced into Kenya around 1970, readily consumes these snails in the laboratory. Field enclosure experiments indicate that crayfish exert a significant negative impact on the abundance of Biomphalaria pfeifferi, the intermediate host of the human blood fluke Schistosoma mansoni. It is likely that P. clarkii will continue to spread naturally in Kenya and that schistosome-transmitting snails will be excluded or reduced in numbers where crayfish are present. Procambarus clarkii may represent an alternative, biological means of snail control in East Africa. PMID:1928568

  4. Complete mitochondrial genome of a freshwater snail, Semisulcospira libertina (Cerithioidea: Semisulcospiridae).

    PubMed

    Zeng, Tai; Yin, Wei; Xia, Rong; Fu, Cuizhang; Jin, Binsong

    2015-12-01

    The first complete mitochondrial genome (mitogenome) of Cerithioidea (Gastropoda: Caenogastropoda) was determined using a freshwater snail Semisulcospira libertina (Cerithioidea: Semisulcospiridae) as a representative species of the superfamily. The mitogenome was 15,432?bp in length, including 13 typical invertebrate protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. The overall base composition was 31.4% for A, 17.8% for C, 34.8% for T and 16.0% for G with a A?+?T bias. The mitogenome of S. libertina displayed novel gene order arrangement compared with published Caenogastropoda mitogenomes to date. This mitogenome contributed in resolving phylogenetic position and interrelationships of Cerithioidea. PMID:24409867

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2016-03-01

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

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

    PubMed Central

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

    2008-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Gao, Wenyuan; Wiederhold, Michael L.

    1997-01-01

    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.

  9. Mineralogy of shells from two freshwater snails Belgrandiella fontinalis and B kuesteri.

    PubMed

    Medakovi?, Davorin; Slapnik, Rajko; Popovi?, Stanko; Grzeta, Biserka

    2003-01-01

    X-ray powder diffraction (XRD) was used to study the mineral composition of shells of snails Belgrandiella fontinalis and Belgrandiella kuesteri collected from three freshwater springs in northeastern Slovenia. The fractions of aragonite, calcite, dolomite and quartz in particular shells were determined. The analysed shells consisted of two or more distinct inorganic layers. The outer shell layer for both species and all sampling localities contained aragonite. The outer layer of B. fontinalis collected at one locality, also contained a small fraction of calcite ( approximately 1 molar%) besides the dominant aragonite. Calcite was identified in the inner layer(s) of both species (2 to 3 molar%), while quartz was found only in B. kuesteri (5-7 molar%). However, both species sampled at one locality showed the presence of dolomite (approx. 20 molar%) in the inner layer(s). The presence of dolomite in the shells of adult gastropods and even molluscs is unusual. A possible formation mechanism and specific ecological factor that could influence the precipitation of dolomite in the shells of different Belgrandiella species is discussed. PMID:12507615

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

    PubMed Central

    Zachar, Nicholas; Neiman, Maurine

    2013-01-01

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

  11. Uptake and distribution of copper sulfate and its effect on the respiration rate of the hemocyanin-producing freshwater snail Lymnaea natalensis

    SciTech Connect

    Wolmarans, C.T.; Yssel, E.

    1988-08-01

    Copper sulfate was one of the earliest compounds suggested as a molluscicide and although several new compounds have since been developed, copper sulfate is still widely used against freshwater snail intermediate hosts of trematode parasites causing bilharzia. However, the toxic effect that copper sulfate may have on these species has not yet been investigated adequately. This incomplete picture of the action of copper sulfate on freshwater snails is further complicated by the fact that some of these snail species have hemocyanin (a protein containing copper) as respiration pigment. Because of the existence of a copper metabolic pathway, these species may handle external copper differently from those species with hemoglobin as respiration pigment. In the present study, the uptake of external copper in the form of copper sulfate, as well as the effect of this ion on respiration rate, was investigated in Lymnaea natalensis, the intermediate host of Fasciola gigantica. This snail possesses hemocyanin as respiratory pigment.

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

    PubMed

    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

    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

  13. Prostaglandin E1, prostaglandin E2, and endotoxin failure to produce fever in the Japanese freshwater snail Semisulcospira libertina.

    PubMed

    Rossetti, Y; Nagasaka, T

    1988-01-01

    The thermopreferendum (preferred temperature) of the Japanese freshwater snail (Semisulcospira libertina) was determined in an aquatic temperature gradient after injection of prostaglandin E1, prostaglandin E2, and LPS. Injected doses of each pyrogen ranged from a toxic dose to less than 1/20th of the toxic dose. Toxic effect of the highest doses of pyrogen disappeared within 120 min. No fever occurred during the 150 min observation following the pyrogen injection. The present results support the hypothesis that fever was selected as a way of defending against infection only after the period of the emergence of the molluscus, i.e., the early Cambrian period. PMID:3172578

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

    SciTech Connect

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

    2010-11-01

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

  15. Metabolomics to Explore Imidacloprid-Induced Toxicity in the Central Nervous System of the Freshwater Snail Lymnaea stagnalis.

    PubMed

    Tufi, Sara; Stel, Jente M; de Boer, Jacob; Lamoree, Marja H; Leonards, Pim E G

    2015-12-15

    Modern toxicology is seeking new testing methods to better understand toxicological effects. One of the most concerning chemicals is the neonicotinoid pesticide imidacloprid. Although imidacloprid is designed to target insects, recent studies have shown adverse effects on nontarget species. Metabolomics was applied to investigate imidacloprid-induced sublethal toxicity in the central nervous system of the freshwater snail Lymnaea stagnalis. The snails (n = 10 snails) were exposed for 10 days to increasing imidacloprid concentrations (0.1, 1, 10, and 100 ?g/L). The comparison between control and exposure groups highlighted the involvement and perturbation of many biological pathways. The levels of several metabolites belonging to different metabolite classes were significantly changed by imidacloprid exposure. A change in the amino acids and nucleotide metabolites like tryptophan, proline, phenylalanine, uridine, and guanosine was found. Many fatty acids were down-regulated, and the levels of the polyamines, spermidine and putrescine, were found to be increased which is an indication of neuron cell injury. A turnover increase between choline and acetylcholine led us to hypothesize an increase in cholinergic gene expression to overcome imidacloprid binding to the nicotinic acetylcholine receptors. Metabolomics revealed imidacloprid induced metabolic changes at low and environmentally relevant concentration in a nontarget species and generated a novel mechanistic hypothesis. PMID:26509427

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

    PubMed Central

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

    2012-01-01

    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

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

    PubMed

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

    2012-01-01

    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

  18. Snails from heavy-metal polluted environments have reduced sensitivity to carbon dioxide-induced acidity.

    PubMed

    Lefcort, Hugh; Cleary, David A; Marble, Aaron M; Phillips, Morgan V; Stoddard, Timothy J; Tuthill, Lara M; Winslow, James R

    2015-01-01

    Anthropogenic atmospheric CO2 reacts with water to form carbonic acid (H2CO3) which increases water acidity. While marine acidification has received recent consideration, less attention has been paid to the effects of atmospheric carbon dioxide on freshwater systems-systems that often have low buffering potential. Since many aquatic systems are already impacted by pollutants such as heavy metals, we wondered about the added effect of rising atmospheric CO2 on freshwater organisms. We studied aquatic pulmonate snails (Physella columbiana) from both a heavy-metal polluted watershed and snails from a reference watershed that has not experienced mining pollution. We used gaseous CO2 to increase water acidity and we then measured changes in antipredatory behavior and also survival. We predicted a simple negative additive effect of low pH. We hypothesized that snails from metal-polluted environments would be physiologically stressed and impaired due to defense responses against heavy metals. Instead, snails from populations that acclimated or evolved in the presence of heavy metal mining pollution were more robust to acidic conditions than were snails from reference habitats. Snails from mining polluted sites seemed to be preadapted to a low pH environment. Their short-term survival in acidic conditions was better than snails from reference sites that lacked metal pollution. In fact, the 48 h survival of snails from polluted sites was so high that it did not significantly differ from the 24 h survival of snails from control sites. This suggests that the response of organisms to a world with rising anthropogenic carbon dioxide levels may be complex and difficult to predict. Snails had a weaker behavioral response to stressful stimuli if kept for 1 month at a pH that differed from their lake of origin. We found that snails raised at a pH of 5.5 had a weaker response (less of a decrease in activity) to concentrated heavy metals than did snails raised at their natal pH of 6.5. Furthermore, snails raised a pH of 5.5, 6.0, and 7.0 all had a weaker antipredatory response to an extract of crushed snail cells than did the pH 6.5 treatment snails. PMID:26090314

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

    PubMed Central

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

    2008-01-01

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

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

    PubMed

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

    2014-06-01

    Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important. PMID:24641838

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

    PubMed

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

    2015-01-01

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

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

    USGS Publications Warehouse

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

    2014-01-01

    Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important.

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

    PubMed Central

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

    2013-01-01

    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

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

    PubMed Central

    Leicht, Katja; Jokela, Jukka; Seppälä, Otto

    2013-01-01

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

  5. Bacterial Diversity and Abundance in Shell Biofilms from the Freshwater Snail Pleurocera canaliculatum (Cerithioidea: Pleuroceridae).

    PubMed

    Minton, Russell L; Creech, Clinton C; Jackson, Debra W

    2015-01-01

    Mollusk shells provide a hard substrate for aquatic biofilm colonization. While most work has focused on bivalve shells and grazing, little work has focused on gastropod shells and the microbes growing on them. We sampled biofilms from 14 Pleuroceracanaliculatum and analyzed them using a metagenomic approach. Microbial diversity varied between individuals, and rarefaction suggested that 63 snails would need to be sampled to capture all of the estimated genus-level diversity. Cyanobacteria and species of Novosphingobium and Methylosoma were the most abundant taxa across all shells. PMID:26373180

  6. The development of Angiostrongylus vasorum (Baillet, 1866) in the freshwater snail Pomacea canaliculata (Lamarck, 1822).

    PubMed

    Mozzer, L R; Coaglio, A L; Dracz, R M; Ribeiro, V M A; Lima, W S

    2015-11-01

    Angiostrongylus vasorum is a parasitic nematode that infects the heart and pulmonary artery and its branches of domestic and wild canids. The parasite can use several species of terrestrial and aquatic molluscs as intermediate hosts, although susceptibility varies. Pomacea canaliculata is a mollusc found in lakes, swamps and rivers in South America. In this study, we evaluated the susceptibility, parasite growth, oviposition and larval development of 282 P. canaliculata infected with 500 A. vasorum first-instar larvae (L1). From day 5 post-infection (pi) to day 30 pi, seven specimens per day were sacrificed to recover the larval instars. We compared 50 egg masses from infected and uninfected molluscs to determine the number of eggs per clutch, the hatching rate and the growth of the molluscs. The percentage of recovered larvae ranged from 39.17% to 67.5%. First-stage larvae (L1) were found until day 19 pi, second-stage larvae (L2) were found from days 11 to 25 pi, and third-stage larvae (L3) were recovered only after day 19 pi. Infected snails exhibited the most eggs during spawning, although the rate of hatching and shell size were lower in the infected snails compared with controls. This is the first report of an experimental infection of P. canaliculata with A. vasorum, and the results confirm the non-specificity of the nematode in relation to the intermediate host and indicate the importance of epidemiological surveys of this parasite and mollusc. PMID:26442708

  7. North American Paleozoic land snails with a summary of other Paleozoic nonmarine snails

    USGS Publications Warehouse

    Solem, Alan; Yochelson, Ellis Leon

    1979-01-01

    Land snails from the Paleozoic of North America are known from the coal fields of eastern Canada, from the Dunkard basin west of the Allegheny Mountains, and from the western margin of the Illinois basin. The earliest finds were made about 125 years ago; essentially no new information has been recorded for a century. Large collections of Anthracopupa from the Dunkard basin sparked inquiry into the land snails from the other two areas. Studies using the SEM (scanning electron microscope) have provided considerable insight into microdetails of shell structure, which allow systematic assignment of these gastropods. All may be assigned to extant families, except one, for which insufficient material allows only superfamily assignment. The prosobranch Dawsonella is confirmed as being a terrestrial neritacean gastropod. To date, it is known only from the upper Middle Pennsylvanian of Illinois and Indiana. All the other Paleozoic land snails are stylommatophoran pulmonates; their current classification as nonmarine cyclophoraceans is not correct. Restudy of material from the Joggins section of Nova Scotia indicates that representatives of two ordinal groups of pulmonates appeared simultaneously in upper Lower Pennsylvanian strata; the oldest land prosobranch is found in only very slightly younger rocks. Zonites (Conulus) priscus is reassigned to the new genus Protodiscus in the extant family Discidae. Dendropupa is placed within the family Enidae, Anthraaopupa is placed in the family Tornatellinidae, and 'Pupa' bigsbii is assigned to the superfamily Pupillacea. All four of these family-level taxa are diverse and belong to two orders within the superorder Stylommatophora, heretofore considered a derived rather than an ancestral stock. Anthracopupa ohioensis Whitfield is a highly variable species, and two other species Naticopsis (?) diminuta and A.(?) dunkardona, both named by Stauffer and Schroyer, are placed in synonymy with it. To obtain taxonomic data to support the family placement of Anthracopupa, growth forms of modern pupillid and tornatellinid snails have been distinguished. The apertural barriers in Anthracopupa are identical in placement and growth pattern with those of living Tornatellinidae and independently confirm the family placement derived from study of the general form. One new species, A. sturgeoni, has been named. Anthracopupa is found most commonly in thin limestones interpreted as having been deposited in pools into which the small shells floated. Dendropupa is most commonly found in erect tree stumps that were covered by rapid sedimentation. Both environments are similar to those in which the shells of allied living species may be found today, and the fossils support environmental interpretations made entirely from lithology. A survey of the few European occurrences of Paleozoic land snails indicates that both Anthracopupa and Dendropupa occur in Lower Permian strata; Anthracopupa is known from beds as old as Westphalian B. These genera cannot be used for determining the Carboniferous-Permian boundary. Both the long local stratigraphic range of A. brittanica and D. vetusta reported in the literature and the moderately long range and great variability of A. ohioensis suggest that the land snails have little stratigraphic utility. On the other hand, the occurrence of these land snails in the late Paleozoic of the Northern Hemisphere provides further fossil evidence suggestive of a closed Atlantic Ocean at that time. A comparison of the Paleozoic and the present distributions of land -snail families on both sides of the Atlantic provides some interesting data on geographic shifts of organisms. Finally, the assignment of the earliest land snails to extant taxa at the family level indicates that the subclass Pulmonata has been very conservative in its evolution after initial radiation. A few notes on Paleozoic freshwater snails complete this survey.

  8. Higher rate of tissue regeneration in polyploid asexual versus diploid sexual freshwater snails

    PubMed Central

    Krois, Nicole R.; Cherukuri, Anvesh; Puttagunta, Nikhil; Neiman, Maurine

    2013-01-01

    Characterizing phenotypic differences between sexual and asexual organisms is a critical step towards understanding why sexual reproduction is so common. Because asexuals are often polyploid, understanding how ploidy influences phenotype is directly relevant to the study of sex and will provide key insights into the evolution of ploidy-level variation. The well-established association between genome size and cell cycle duration, evidence for a link between genome size and tissue regeneration rate and the growing body of research showing that ploidy influences growth rate and gene expression led us to hypothesize that healing and tissue regeneration might be affected by ploidy-level variation. We evaluated this hypothesis by measuring the rate of regeneration of antenna tissue of Potamopyrgus antipodarum, a New Zealand snail characterized by frequent coexistence between diploid sexuals and polyploid asexuals. Antennae of triploid and presumptive tetraploid asexuals regenerated more rapidly than the antennae of diploid sexuals, but regeneration rate did not differ between triploids and tetraploids. These results suggest either that ploidy elevation has nonlinear positive effects on tissue regeneration and/or that factors associated directly with reproductive mode affect regeneration rate more than ploidy level. The results of this study also indicate that the lower ploidy of sexual P. antipodarum is unlikely to confer advantages associated with more rapid regeneration. PMID:23843218

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2013-11-01

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

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

    PubMed Central

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

    2014-01-01

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

  12. Where are the South American freshwater turtle blood flukes (Trematoda: Spirorchiidae)? The first morphological and molecular analysis of spirorchiid cercariae from freshwater snails in Brazil.

    PubMed

    Pinto, Hudson Alves; de Melo, Alan Lane; Brant, Sara Vanessa

    2015-12-01

    Trematodes belonging to the family Spirorchiidae are blood parasites mainly of turtles with a worldwide distribution. These flukes were recently reported in some marine turtles from South America, where the occurrence of spirorchiids in freshwater definitive and intermediate hosts is so far unknown. In the present study, three morphotypes of brevifurcate apharyngeate distome cercariae found in freshwater molluscs from an urban reservoir in Brazil were used for morphological and molecular (nuclear 28S rDNA) evaluation. Two morphotypes of cercariae, probably congeneric species, were found in 12/17,465 specimens of Biomphalaria spp. and differ from each other by body size and sequences (0.1%). They present morphology similar to North American freshwater spirorchiids (Spirorchis spp.), however surprisingly molecular data reveals that these lineages are more closely related to marine spirorchiids. A third species found in 2/777 Pomacea sp. differs morphologically from all previously described spirorchiid cercariae and genetically from spirorchiids with available sequences (16-19%), grouping in the phylogenetic tree with freshwater North American species. This is the first report of freshwater spirorchiids in South America and the first molecular confirmation of the involvement of a caenogastropod in the life cycle of spirorchiids. PMID:26253761

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

    PubMed

    Hanif, Farhat; Singh, Dinesh Kumar

    2013-12-01

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

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

    PubMed Central

    Hanif, Farhat; Singh, Dinesh Kumar

    2013-01-01

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

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

    PubMed

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

    2004-04-01

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

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

    PubMed

    Stoiber, Tasha; Croteau, Marie-Noële; Römer, Isabella; Tejamaya, Mila; Lead, Jamie R; Luoma, Samuel N

    2015-10-01

    The release of Ag nanoparticles (AgNPs) into the aquatic environment is likely, but the influence of water chemistry on their impacts and fate remains unclear. Here, we characterize the bioavailability of Ag from AgNO3 and from AgNPs capped with polyvinylpyrrolidone (PVP AgNP) and thiolated polyethylene glycol (PEG AgNP) in the freshwater snail, Lymnaea stagnalis, after short waterborne exposures. Results showed that water hardness, AgNP capping agents, and metal speciation affected the uptake rate of Ag from AgNPs. Comparison of the results from organisms of similar weight showed that water hardness affected the uptake of Ag from AgNPs, but not that from AgNO3. Transformation (dissolution and aggregation) of the AgNPs was also influenced by water hardness and the capping agent. Bioavailability of Ag from AgNPs was, in turn, correlated to these physical changes. Water hardness increased the aggregation of AgNPs, especially for PEG AgNPs, reducing the bioavailability of Ag from PEG AgNPs to a greater degree than from PVP AgNPs. Higher dissolved Ag concentrations were measured for the PVP AgNPs (15%) compared to PEG AgNPs (3%) in moderately hard water, enhancing Ag bioavailability of the former. Multiple drivers of bioavailability yielded differences in Ag influx between very hard and deionized water where the uptake rate constants (kuw, l?g(-1)?d(-1)?±?SE) varied from 3.1?±?0.7 to 0.2?±?0.01 for PEG AgNPs and from 2.3?±?0.02 to 1.3?±?0.01 for PVP AgNPs. Modeling bioavailability of Ag from NPs revealed that Ag influx into L. stagnalis comprised uptake from the NPs themselves and from newly dissolved Ag. PMID:25676617

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

    USGS Publications Warehouse

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

    2015-01-01

    The release of Ag nanoparticles (AgNPs) into the aquatic environment is likely, but the influence of water chemistry on their impacts and fate remains unclear. Here, we characterize the bioavailability of Ag from AgNO3 and from AgNPs capped with polyvinylpyrrolidone (PVP AgNP) and thiolated polyethylene glycol (PEG AgNP) in the freshwater snail, Lymnaea stagnalis, after short waterborne exposures. Results showed that water hardness, AgNP capping agents, and metal speciation affected the uptake rate of Ag from AgNPs. Comparison of the results from organisms of similar weight showed that water hardness affected the uptake of Ag from AgNPs, but not that from AgNO3. Transformation (dissolution and aggregation) of the AgNPs was also influenced by water hardness and the capping agent. Bioavailability of Ag from AgNPs was, in turn, correlated to these physical changes. Water hardness increased the aggregation of AgNPs, especially for PEG AgNPs, reducing the bioavailability of Ag from PEG AgNPs to a greater degree than from PVP AgNPs. Higher dissolved Ag concentrations were measured for the PVP AgNPs (15%) compared to PEG AgNPs (3%) in moderately hard water, enhancing Ag bioavailability of the former. Multiple drivers of bioavailability yielded differences in Ag influx between very hard and deionized water where the uptake rate constants (kuw, l g-1 d-1 ± SE) varied from 3.1?±?0.7 to 0.2?±?0.01 for PEG AgNPs and from 2.3?±?0.02 to 1.3?±?0.01 for PVP AgNPs. Modeling bioavailability of Ag from NPs revealed that Ag influx into L. stagnalis comprised uptake from the NPs themselves and from newly dissolved Ag.

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

    PubMed

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

    2009-02-01

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

  19. Pulmonic Valve Repair in a Patient with Isolated Pulmonic Valve Endocarditis and Sickle Cell Disease

    PubMed Central

    Glew, Timothy; Feliciano, Migdalia; Finkielstein, Dennis; Hecht, Susan; Hoffman, Daryl

    2015-01-01

    A 49-year-old woman with sickle cell disease presented with one month of exertional dyspnea, weakness, and fever and was diagnosed with isolated pulmonic valve endocarditis secondary to methicillin-resistant Staphylococcus bacteremia in the setting of a peripherally inserted central venous catheter. Chest computerized tomography showed multiple bilateral pulmonary nodular opacities consistent with septic emboli. Transthoracic and transesophageal echocardiograms revealed a large echodensity on the pulmonic valve requiring vegetation excision and pulmonic valve repair. In conclusion, isolated pulmonic valve endocarditis is a rare cause of infective endocarditis that warrants a high index of clinical suspicion. Furthermore the management of patients with sickle cell disease and endocarditis requires special consideration. PMID:26199760

  20. Pulmonic Ingressive Speech in Shetland English

    ERIC Educational Resources Information Center

    Sundkvist, Peter

    2012-01-01

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

  1. Snails home

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

  2. 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....

  3. Assessment of mercury toxicity by the changes in oxygen consumption and ion levels in the freshwater snail, Pila globosa, and the mussel, Lamellidens marginalis

    SciTech Connect

    Sivaramakrishna, B.; Radhakrishnaiah, K.; Suresh, A. )

    1991-06-01

    There are many studies on mercury toxicity in freshwater fishes but very few on freshwater molluscs (Wright 1978) though they serve as bio-indicators of metal pollution. A few reports on marine gastropods and bivalves indicated the importance of these animals in metal toxicity studies. Hence, in the present study, the level of tolerance of the freshwater gastropod Pila globosa and of a freshwater bivalve Lamellidens marginalis mercury at lethal and sublethal levels was determined and compared with the rate of whole animal oxygen consumption and the level of sodium, potassium and calcium ions in the hepatopancreas and the foot of these animals. As the period of exposure is one of the important factors in toxicity studies, the level of tolerance was determined at 120 hours of exposure and the other parameters were analyzed at 1, 3 and 5 days in lethal and at 1, 7 and 15 days in sublethal concentrations.

  4. Supercharged Snails for Stream Ecology & Water-Quality Studies

    ERIC Educational Resources Information Center

    Stewart, Arthur J.; Ryon, Michael G.

    2003-01-01

    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…

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

    PubMed Central

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

    2008-01-01

    In the present study, a tandem-repeat type galectin was characterized from an embryonic cell line (Bge) and circulating hemocytes of the snail Biomphalaria glabrata, intermediate host of the human blood fluke Schistosoma mansoni. The predicted B. glabrata galectin (BgGal) protein of 32 kDa possessed 2 carbohydrate recognition domains, each displaying 6 of 8 conserved amino acids involved in galactoside-binding activity. A recombinant BgGal (rBgGal) demonstrated hemagglutinating activity against rabbit erythrocytes, which was specifically inhibited by galactose-containing sugars (lacNAc/lac > galNAc/gal). Although native galectin was immunolocalized in the cytoplasm of Bge cells and the plasma membrane of a subset of snail hemocytes (60%), it was not detected in cell-free plasma by Western blot analysis. The findings that rBgGal selectively recognizes the schistosome-related sugar, lacNAc, and strongly binds to hemocytes and the tegument of S. mansoni sporocysts in a sugar-inhibitable fashion suggest that hemocyte-bound galectin may be serving as pattern recognition receptor for this, or other pathogens possessing appropriate sugar ligands. Based on molecular and functional features, BgGal represents an authentic galectin, the first to be fully characterized in the medically-important molluscan Class Gastropoda. PMID:18280060

  6. Fecundity of the Chinese mystery snail in a Nebraska reservoir

    USGS Publications Warehouse

    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

    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.

  7. Cercarial Dermatitis Transmitted by Exotic Marine Snail

    PubMed Central

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

    2010-01-01

    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

  8. Unravelling the riddle of Radix: DNA barcoding for species identification of freshwater snail intermediate hosts of zoonotic digeneans and estimating their inter-population evolutionary relationships.

    PubMed

    Lawton, Scott P; Lim, Rivka M; Dukes, Juliet P; Kett, Stephen M; Cook, Richard T; Walker, Anthony J; Kirk, Ruth S

    2015-10-01

    Radix spp. are intermediate host snails for digenean parasites of medical and veterinary importance. Within this genus, species differentiation using shell and internal organ morphology can result in erroneous species identification, causing problems when trying to understand the population biology of Radix. In the present study, DNA barcoding, using cox1 and ITS2 sequences, identified populations of Radix auricularia and Radix balthica from specimens originally morphologically identified as Radix peregra from the UK. Assessment of cox1 and ITS2 as species identification markers showed that, although both markers differentiated species, cox1 possessed greater molecular diversity and higher phylogenetic resolution. Cox1 also proved useful for gaining insights into the evolutionary relationships of Radix species populations. Phylogenetic analysis and haplotype networks of cox1 indicated that R. auricularia appeared to have invaded the UK several times; some haplotypes forming a distinct UK specific clade, whilst others are more akin to those found on mainland Europe. This was in contrast to relationships between R. balthica populations, which had low molecular diversity and no distinct UK specific haplotypes, suggesting recent and multiple invasions from mainland Europe. Molecular techniques therefore appear to be crucial for distinguishing Radix spp., particularly using cox1. This barcoding marker also enables the population biology of Radix spp. to be explored, and is invaluable for monitoring the epidemiology of fluke diseases especially in the light of emerging diseases and food security. PMID:26196736

  9. Severe pulmonic valve regurgitation due to histoplasma endocarditis

    PubMed Central

    Bremer, Merri; Lin, Peter T; Pislaru, Sorin V

    2015-01-01

    Summary A 67-year-old man with myelodysplastic syndrome, disseminated histoplasmosis, and mitral valve replacement presented with dyspnea and peripheral edema. Transthoracic echocardiography demonstrated abnormal pulmonic valve with possible vegetation. Color flow imaging showed laminar flow from main pulmonary artery into right ventricular outflow tract (RVOT) in diastole. The continuous wave Doppler signal showed dense diastolic envelope with steep deceleration slope. These findings were consistent with severe pulmonic valve regurgitation, possibly due to endocarditis. Transesophageal echocardiography demonstrated an echodense mass attached to the pulmonic valve. The mitral valve bioprosthesis appeared intact. Bacterial and fungal blood cultures were negative; however, serum histoplasma antigen was positive. At surgery, the valve appeared destroyed by vegetations. Gomori methenamine silver-stains showed invasive fungal hyphae and yeast consistent with a dimorphic fungus. Valve cultures grew one colony of filamentous fungus. Itraconazole was continued based on expert infectious diseases diagnosis. After surgery, dyspnea and ankle edema resolved. To the best of our knowledge, histoplasma endocarditis of pulmonic valve has not been previously reported. Isolated pulmonic valve endocarditis is rare, accounting for about 2% of infectious endocarditis (IE) cases. Fungi account for about 3% of cases of native valve endocarditis. Characterization of pulmonary valve requires thorough interrogation with 2D and Doppler echocardiography techniques. Parasternal RVOT view allowed visualization of the pulmonary valve and assessment of regurgitation severity. As an anterior structure, it may be difficult to image with transesophageal echocardiography. Mid-esophageal right ventricular inflow–outflow view clearly showed the pulmonary valve and vegetation. Learning points Identification and characterization of pulmonary valve abnormalities require thorough interrogation with 2D and Doppler echocardiography techniques.Isolated pulmonary valve IE is rare and requires high index of suspicion. Histoplasma capsulatum IE is rare and requires high index of suspicion. PMID:26693325

  10. The convoluted evolution of snail chirality

    NASA Astrophysics Data System (ADS)

    Schilthuizen, M.; Davison, A.

    2005-11-01

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

  11. Silicosis Caused by Chronic Inhalation of Snail Shell Powder

    PubMed Central

    Jung, Jae Woo; Lee, Byung Ook; Lee, Jae Hee; Park, Sung Woon; Kim, Bo Min; Choi, Jae Chol; Shin, Jong Wook; Park, In Won; Choi, Byoung Whui

    2012-01-01

    A 70-yr-old woman visited our hospital for shortness of breath. Chest CT showed ground glass opacity and traction bronchiectasis at right middle, lower lobe and left lingular division. Video-assisted thoracic surgical biopsy at right lower lobe and pathologic examination revealed mixed dust pneumoconiosis. Polarized optical microscopy showed lung lesions were consisted of silica and carbon materials. She was a housewife and never been exposed to silica dusts occupationally. She has taken freshwater snails as a health-promoting food for 40 yr and ground shell powder was piled up on her backyard where she spent day-time. Energy dispersive X-ray spectroscopy of snail shell and scanning electron microscopy with energy dispersive x-ray spectroscopy of lung lesion revealed that silica occupies important portion. Herein, we report the first known case of silicosis due to chronic inhalation of shell powder of freshwater snail. PMID:22219621

  12. Copper toxicity to the fresh water snail, Lymnaea luteola

    SciTech Connect

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

    1987-07-01

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

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

    PubMed Central

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

    1997-01-01

    Complete gene organizations of the mitochondrial genomes of three pulmonate gastropods, Euhadra herklotsi, Cepaea nemoralis and Albinaria coerulea, permit comparisons of their gene organizations. Euhadra and Cepaea are classified in the same superfamily, Helicoidea, yet they show several differences in the order of tRNA and protein coding genes. Albinaria is distantly related to the other two genera but shares the same gene order in one part of its mitochondrial genome with Euhadra and in another part with Cepaea. Despite their small size (14.1-14.5 kbp), these snail mtDNAs encode 13 protein genes, two rRNA genes and at least 22 tRNA genes. These genomes exhibit several unusual or unique features compared to other published metazoan mitochondrial genomes, including those of other molluscs. Several tRNAs predicted from the DNA sequences possess bizarre structures lacking either the T stem or the D stem, similar to the situation seen in nematode mt-tRNAs. The acceptor stems of many tRNAs show a considerable number of mismatched basepairs, indicating that the RNA editing process recently demonstrated in Euhadra is widespread in the pulmonate gastropods. Strong selection acting on mitochondrial genomes of these animals would have resulted in frequent occurrence of the mismatched basepairs in regions of overlapping genes. PMID:9055084

  14. [Geographic variations in freshwater molluscs].

    PubMed

    Vinarski?, M V

    2012-01-01

    The phenomenon of geographic variation is known in practically all taxa of living beings. However, the reality of this phenomenon in freshwater molluscs (snails and bivalves) has many times been questioned in the past. It was accepted that these animals do not demonstrate spatially-oriented variation, where specific "local race" is arisen in each specific habitat. Till the beginning of 1970s, there was no statistical evidence that geographic clines in freshwater molluscs really exist. However, a few species of freshwater molluscs has been studied in this respect so far, therefore it is almost impossible to draw any general patterns of geographical variation in this group of animals. Most species of freshwater molluscs studied to the date exhibit statistically significant decrease of their body size in the south-north direction. Perhaps, it may be explained by decrease of the duration of the growth season in high latitudes. Some species of freshwater snails demonstrate clinal changes in shell proportions. This allows to reject subspecies separation within these species since diagnostic characters of such "subspecies" may blur when geographic variation is taken into consideration. The data on geographic variation in anatomical traits in freshwater molluscs is much more scarce. At least one species of pond snails (Lymnaea terebra) demonstrates clinal variation in proportions of the copulative apparatus in the south-north direction. Further studies of geographic variation in freshwater molluscs should reveal whether it is truly adaptive, i.e. whether geographical clines have underlying genetic basis. Otherwise, the clines may arise as a result of direct modifying effect of a habitat. PMID:22590907

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

    USGS Publications Warehouse

    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

    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.

  16. Snails & SlugsSnails & Slugs Snails and slugs rank among our most

    E-print Network

    Ishida, Yuko

    and slugs without using pesticides? Make sure the garden is mollusk-free before planting. Then erectSnails & SlugsSnails & Slugs Snails and slugs rank among our most despised garden pests. These slimy mollusks emerge from hiding at night and chew holes in leaves and flowers of many succulent garden

  17. Isolated pulmonic valve endocarditis presenting as neck pain

    PubMed Central

    Goud, Aditya; Abdelqader, Abdelhai; Dahagam, Chanukya; Padmanabhan, Sriram

    2015-01-01

    We discuss a unique case of a 52-year-old man with no history of intravenous drug use or dental procedures who presented with neck pain, 2 weeks of fevers, chills, night sweats, cough, and dyspnea found to have isolated pulmonic valve (PV) endocarditis. The patient did not have an associated murmur, which is commonly seen in right-sided infectious endocarditis. A transthoracic echocardiogram showed a thickened PV leaflet, with subsequent transesophageal echocardiogram showing a PV mass. Speciation of blood cultures revealed Streptococcus oralis. In right-sided infective endocarditis, usually the tricuspid valve is involved; however, in our case the tricuspid valve was free of any mass or vegetation. The patient did meet Duke criteria and was thus started on long-term intravenous antibiotics for infectious endocarditis. The patient's symptoms quickly improved with antibiotics. A careful history and evaluating the patient's risk factors are key in earlier detection of infective endocarditis (IE). Because of early detection and a high index of suspicion, the patient had no further complications and did not require any surgery. In conclusion, clinical suspicion of right-sided IE should be high in patients who present with persistent fevers and pulmonary symptoms in order to reduce the risk of complications, and to improve outcomes. PMID:26653697

  18. Inquiry, Land Snails, and Environmental Factors.

    ERIC Educational Resources Information Center

    Barrow, Lloyd H.; Krantz, Patrick D.

    2002-01-01

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

  19. Eastern Heath Snail Terrestrial snail in the Hygromiidae family

    E-print Network

    Dyer, Bill

    . Biology & Behavior: found in vegetation, under rocks, boards, and refuse. Known for climbing on vegetation proper disposal. Artificial Movement Prevention and Inspection Various articles can provide snails

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

    USGS Publications Warehouse

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

    2012-01-01

    We assessed how spatial and temporal heterogeneity and competition structure larval trematode communities in the pulmonate snail Lymnaea stagnalis. To postulate a dominance hierarchy, mark-release-recapture was used to monitor replacements of trematode species within snails over time. In addition, we sampled the trematode community in snails in different ponds in 3 consecutive years. A total of 7,623 snails (10,382 capture events) was sampled in 7 fishponds in the Jind?ich?v Hradec and T?ebo? areas in South Bohemia (Czech Republic) from August 2006 to October 2008. Overall, 39% of snails were infected by a community of 14 trematode species; 7% of snails were infected with more than 1 trematode species (constituting 16 double- and 4 triple-species combinations). Results of the null-model analyses suggested that spatial heterogeneity in recruitment among ponds isolated trematode species from each other, whereas seasonal pulses in recruitment increased species interactions in some ponds. Competitive exclusion among trematodes led to a rarity of multiple infections compared to null-model expectations. Competitive relationships among trematode species were hypothesized as a dominance hierarchy based on direct evidence of replacement and invasion and on indirect evidence. Seven top dominant species with putatively similar competitive abilities (6 rediae and 1 sporocyst species) reduced the prevalence of the other trematode species developing in sporocysts only.

  1. Synchronous and Non-Synchronous Semelparity in Sibling Species of Pulmonates.

    PubMed

    Nyumura, Nobuhiro; Asami, Takahiro

    2015-08-01

    Diverse life histories have been documented in terrestrial pulmonates, which inhabit different regions in climate. Life history traits are often phenotypically plastic and vary depending on the environment. Thus, surveys using designs that control for the confounding effects of environment are needed to evaluate the evolutionary differences between populations of closely related species in the wild. We examined the life histories of sibling species of terrestrial pulmonate within two regions of similar climates. Bradybaena pellucida (BP) is endemic to Japanese islands, and has recently been expanding its distribution northeastward, whereas B. similaris (BS) has been introduced by humans into temperate and tropical regions worldwide. We found that these species exhibit discrete differences in population dynamics and life cycle, despite their close relatedness. The annual life cycle of BP is synchronized among individuals in a population. Thus, BP is univoltine with discontinuous generation. In contrast, BS individuals do not synchronize their growth or reproduction, and thus exhibit overlapping generations. Our results indicate that synchronized and non-synchronized population dynamics diverge relatively rapidly in semelparous pulmonates. This type of difference has not been documented in pulmonate life history, and may have been overlooked because only a few studies have explicitly compared life cycles of closely related species within the same climate. Our results provide a basis for further studies of life history evolution in pulmonates. PMID:26245224

  2. Spatial mosaic evolution of snail defensive traits

    PubMed Central

    Johnson, Steven G; Hulsey, C Darrin; de León, Francisco J García

    2007-01-01

    Background Recent models suggest that escalating reciprocal selection among antagonistically interacting species is predicted to occur in areas of higher resource productivity. In a putatively coevolved interaction between a freshwater snail (Mexipyrgus churinceanus) and a molluscivorous cichlid (Herichthys minckleyi), we examined three components of this interaction: 1) spatial variation in two putative defensive traits, crushing resistance and shell pigmentation; 2) whether abiotic variables or frequency of molariform cichlids are associated with spatial patterns of crushing resistance and shell pigmentation and 3) whether variation in primary productivity accounted for small-scale variation in these defensive traits. Results Using spatial autocorrelation to account for genetic and geographic divergence among populations, we found no autocorrelation among populations at small geographic and genetic distances for the two defensive traits. There was also no correlation between abiotic variables (temperature and conductivity) and snail defensive traits. However, crushing resistance and frequency of pigmented shells were negatively correlated with molariform frequency. Crushing resistance and levels of pigmentation were significantly higher in habitats dominated by aquatic macrophytes, and both traits are phenotypically correlated. Conclusion Crushing resistance and pigmentation of M. churinceanus exhibit striking variation at small spatial scales often associated with differences in primary productivity, substrate coloration and the frequency of molariform cichlids. These local geographic differences may result from among-habitat variation in how resource productivity interacts to promote escalation in prey defenses. PMID:17397540

  3. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research

    E-print Network

    Krug, Patrick J.

    in a major radiation of gastropod molluscs Kevin M. Kocot a , Kenneth M. Halanych a , Patrick J. Krug b and freshwater snails and slugs. However, recent studies drew conflicting conclusions about pulmonate monophyly into a monophyletic Opisthobranchia, a traditional group of sea slugs long considered sister to pulmonates. Conversely

  4. Habitat requirements of the pulmonate land snails Trochulus oreinos oreinos and Cylindrus obtusus endemic to the Northern Calcareous Alps, Austria

    PubMed Central

    Duda, Michael; Kruckenhauser, Luise; Haring, Elisabeth; Sattmann, Helmut

    2014-01-01

    The habitat needs and potential threats to Trochulus oreinos oreinos (Wagner 1915) and Cylindrus obtusus (Draparnaud 1805) were assessed by comparing vegetation maps and our own records. We selected four sites from which we had adequate samples and for which exact vegetation maps were available: the mountains Hoch-schwab, Schneealpe, Rax and Schneeberg. Both taxa prefer open dry alpine grassland with diggable soil and/or stones. T. oreinos oreinos is restricted to subalpine and alpine boulder societies and Caricetum firmae. While C. obtusus dwells on several communities of plants, it seems to be bound to unconsolidated stony ground. As both taxa prefer naturally forest-free areas, they are not affected by structural changes of the habitat, such as reforestation caused by the abandonment of grazing and the shift of vegetation zones. But it has to be considered that T. oreinos oreinos and C. obtusus are limited by microclimatic factors, as they prefer cooler habitats. The mountains Schneealpe, Rax and Schneeberg, reaching barely 2000 m in height, are on the climatic limit of the species distribution. Therefore, the investigated taxa are vulnerable to the upward shift of climate zones. T. oreinos oreinos shows striking similarities in its habitat preference to the Swiss endemic T. biconicus, as both taxa prefer the same dry alpine habitats which are quite different to those of other representatives of the genus, which prefer damp habitats. PMID:25729612

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

    EPA Science Inventory

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

  6. An artificial perch to help Snail Kites handle an exotic Apple Snail

    USGS Publications Warehouse

    Pias, Kyle E.; Welch, Zach C.; Kitchens, Wiley M.

    2012-01-01

    In the United States, the Snail Kite (Rostrhamus sociabilis plumbeus) is a federally endangered species and restricted to the wetlands of south-central Florida where the current population numbers less than 1,500. The Snail Kite is an extreme dietary specialist, previously feeding almost exclusively on one species of snail, the Florida Apple Snail (Pomacea paludosa). Within the past decade, an exotic species of apple snail, the Island Apple Snail (Pomacea insularum), has become established on lakes in central Florida. Island Apple Snails are larger than the native Florida Apple Snails, and Snail Kites handle the exotic snails less efficiently. Juvenile Snail Kites, in particular, have lower daily energy balances while feeding on Island Apple Snails. An inexpensive, easy-to-construct platform was developed that would provide Snail Kites with a flat, stable surface on which to extract snails. The platform has the potential to reduce the difficulties Snail Kites experience when handling exotic snails, and may benefit the Snail Kite population as a whole. Initial observations indicate that Snail Kites use the platforms frequently, and snails extracted at the platforms are larger than snails extracted at other perches.

  7. Freshwater Macroinvertebrates.

    ERIC Educational Resources Information Center

    Nalepa, T. F.

    1978-01-01

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

  8. Alterations of biochemical indicators in hepatopancreas of the golden apple snail, Pomacea canaliculata, from paddy fields in Taiwan.

    PubMed

    Chiu, Yuh-Wen; Wu, Jui-Pin; Hsieh, Tsung-Chih; Liang, Shih-Hsiung; Chen, Chien-Min; Huang, Da-Ji

    2014-07-01

    The freshwater golden apple snail, Pomacea canaliculata, is one of the world's 100 worst invasive alien species. The snails' wide distribution, high abundance, and sensitivity to environmental pollution make them a potential bioindicator for environmental contamination. In this study, the biochemical status of golden apple snails collected from paddy fields throughout the island of Taiwan was examined. This study found that the biochemical status of apple snails collected from paddy fields differed from that of animals bred and maintained in the laboratory. Furthermore, certain biochemical endpoints of the snails collected from the paddy fields before and after agricultural activities were also different-hemolymphatic vitellogenin protein was induced in male snail after exposure to estrogen-like chemicals, the hepatic monooxygenase (1.97 +/- 0.50 deltaA(650mm) 30 min(-1) mg(-1) protein in control group) and glutathione S transferase (0.02 +/- 0.01 delta A(340mm) 30 min(-1) mg(-1) protein in control group) snails exposed to pesticides, as well as the hepatopancreatic levels of aspartate aminotransferase (450.00 +/- 59.40 U mg(-1) mg(-1) protein in control group) and alanine aminotransferase (233.27 +/- 42.09 U mg(-1) mg(-1) protein in control group) decreased the indicating that xenobiotics destroyed hepatopancreatic. The above findings reveal that apple snail could be used as a practical bioindicator to monitor anthropogenic environmental pollution. PMID:25004751

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

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

    PubMed Central

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

    2012-01-01

    Non-native species and habitat degradation are two major catalysts of environmental change and often occur simultaneously. In freshwater systems, degradation of adjacent terrestrial vegetation may facilitate introduced species by altering resource availability. Here we examine how the presence of intact riparian cover influences the impact of an invasive herbivorous snail, Tarebia granifera, on nitrogen (N) cycling in aquatic systems on the island of Trinidad. We quantified snail biomass, growth, and N excretion in locations where riparian vegetation was present or removed to determine how snail demographics and excretion were related to the condition of the riparian zone. In three Neotropical streams, we measured snail biomass and N excretion in open and closed canopy habitats to generate estimates of mass- and area-specific N excretion rates. Snail biomass was 2 to 8 times greater and areal N excretion rates ranged from 3 to 9 times greater in open canopy habitats. Snails foraging in open canopy habitat also had access to more abundant food resources and exhibited greater growth and mass-specific N excretion rates. Estimates of ecosystem N demand indicated that snail N excretion in fully closed, partially closed, and open canopy habitats supplied 2%, 11%, and 16% of integrated ecosystem N demand, respectively. We conclude that human-mediated riparian canopy loss can generate hotspots of snail biomass, growth, and N excretion along tropical stream networks, altering the impacts of an invasive snail on the biogeochemical cycling of N. PMID:22761706

  11. Susceptibility of Snails to Infection with Schistosomes is influenced by Temperature and Expression of Heat Shock Proteins

    PubMed Central

    Knight, Matty; Elhelu, O; Smith, M; Haugen, B; Miller, A; Raghavan, N; Wellman, C; Cousin, C; Dixon, F; Mann, V; Rinaldi, G; Ittiprasert, W; Brindley, PJ

    2015-01-01

    The freshwater snail, Biomphalaria glabrata is the obligate intermediate host for the transmission of the parasitic trematode, Schistosoma mansoni the causative agent of the chronic debilitating neglected tropical disease, schistosomiasis. We showed previously that in juvenile snails, early and significant induction of stress manifested by the expression of stress proteins, Hsp 70, Hsp 90 and reverse transcriptase (RT) of the non- LTR retrotransposon, nimbus, is a characteristic feature of juvenile susceptible NMRI but not resistant BS-90 snails. These latter, however, could be rendered susceptible after mild heat shock at 32°C, revealing that resistance in the BS-90 resistant snail to schistosomes is a temperature dependent trait. Here we tested the hypothesis that maintenance of BS-90 resistant snails at the permissive temperature for several generations affects the resistance phenotype displayed at the non-permissive temperature of 25°C. The progeny of BS-90 snails bred and maintained through several generations (F1 to F4) at 32°C were susceptible to the schistosome infection when returned to room temperature, shedding cercariae at four weeks post-infection. Moreover, the study of expression levels of the heat shock protein (Hsp) 70 protein by ELISA and western blot analysis, showed that this protein is also differentially expressed between susceptible and resistant snails, with susceptible snails expressing more protein than their resistant counterparts after early exposure to wild-type but not to radiation-attenuated miracidia. These data suggested that in the face of global warming, the ability to sustain a reduction in schistosomiasis by using refractory snails as a strategy to block transmission of the disease might prove challenging since non-lethal elevation in temperature, affects snail susceptibility to S. mansoni. PMID:26504668

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

    NASA Astrophysics Data System (ADS)

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

    2003-06-01

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

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

    PubMed Central

    Hoso, Masaki

    2012-01-01

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

  14. Histamine Immunoreactive Elements in the Central and Peripheral Nervous Systems of the Snail, Biomphalaria spp., Intermediate Host for Schistosoma mansoni

    PubMed Central

    Habib, Mohamed R.; Mohamed, Azza H.; Osman, Gamalat Y.; Sharaf El-Din, Ahmed T.; Mossalem, Hanan S.; Delgado, Nadia; Torres, Grace; Rolón-Martínez, Solymar; Miller, Mark W.; Croll, Roger P.

    2015-01-01

    Histamine appears to be an important transmitter throughout the Animal Kingdom. Gastropods, in particular, have been used in numerous studies establishing potential roles for this biogenic amine in the nervous system and showing its involvement in the generation of diverse behaviours. And yet, the distribution of histamine has only previously been described in a small number of molluscan species. The present study examined the localization of histamine-like immunoreactivity in the central and peripheral nervous systems of pulmonate snails of the genus Biomphalaria. This investigation demonstrates immunoreactive cells throughout the buccal, cerebral, pedal, left parietal and visceral ganglia, indicative of diverse regulatory functions in Biomphalaria. Immunoreactivity was also present in statocyst hair cells, supporting a role for histamine in graviception. In the periphery, dense innervation by immunoreactive fibers was observed in the anterior foot, perioral zone, and other regions of the body wall. This study thus shows that histamine is an abundant transmitter in these snails and its distribution suggest involvement in numerous neural circuits. In addition to providing novel subjects for comparative studies of histaminegic neurons in gastropods, Biomphalaria is also the major intermediate host for the digenetic trematode parasite, which causes human schistosomiasis. The study therefore provides a foundation for understanding potential roles for histamine in interactions between the snail hosts and their trematode parasites. PMID:26086611

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

    PubMed

    Hoso, Masaki

    2012-12-01

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

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

    USGS Publications Warehouse

    Riggs, A.C.

    1984-01-01

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

  17. INTRODUCTION Embryos of the freshwater common pond snail Lymnaea stagnalis

    E-print Network

    Grosell, Martin

    of acid and base equivalents under calcifying, post- metamorphic conditions. We found that the onset of apparent net titratable alkalinity uptake/acid extrusion was concurrent with metamorphosis, the onset of Ca titratable alkalinity uptake/acid extrusion was significantly reduced, but not inhibited, under HCO3 ­ -free

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

    PubMed Central

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

    2014-01-01

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

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

    SciTech Connect

    Woin, P.; Broenmark, C. )

    1992-01-01

    Reproduction is the single most important function in the life cycle of an organism. Successful reproduction determines fitness of organisms. The inability of an organism to complete any one stage of the reproductive process severely reduces its lifetime reproductive success. Disruptions in the reproduction will ultimately affect the abundance and distribution of the species. Therefore, laboratory tests of long-term impact of sublethal pollutant concentrations on organisms preferably is done on the reproductive success. Pollutants of diverse structure may affect the reproductive system which is sensitive to toxic agents. Certain pollutants, notably the organochlorine compounds, have been shown to affect the male and female reproductive systems. The authors have studied the effect of sublethal concentrations of DDT and the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) on the reproductive output of the pulmonate snail Lymnaea stagnalis under a 2-mon exposure period.

  20. 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...

  1. Analysis of snail genes in the crustacean Parhyale hawaiensis: insight into snail gene family evolution.

    PubMed

    Hannibal, Roberta L; Price, Alivia L; Parchem, Ronald J; Patel, Nipam H

    2012-05-01

    The transcriptional repressor snail was first discovered in Drosophila melanogaster, where it initially plays a role in gastrulation and mesoderm formation, and later plays a role in neurogenesis. Among arthropods, this role of snail appears to be conserved in the insects Tribolium and Anopheles gambiae, but not in the chelicerates Cupiennius salei and Achaearanea tepidariorum, the myriapod Glomeris marginata, or the Branchiopod crustacean Daphnia magna. These data imply that within arthropoda, snail acquired its role in gastrulation and mesoderm formation in the insect lineage. However, crustaceans are a diverse group with several major taxa, making analysis of more crustaceans necessary to potentially understand the ancestral role of snail in Pancrustacea (crustaceans + insects) and thus in the ancestor of insects as well. To address these questions, we examined the snail family in the Malacostracan crustacean Parhyale hawaiensis. We found three snail homologs, Ph-snail1, Ph-snail2 and Ph-snail3, and one scratch homolog, Ph-scratch. Parhyale snail genes are expressed after gastrulation, during germband formation and elongation. Ph-snail1, Ph-snail2, and Ph-snail3 are expressed in distinct patterns in the neuroectoderm. Ph-snail1 is the only Parhyale snail gene expressed in the mesoderm, where its expression cycles in the mesodermal stem cells, called mesoteloblasts. The mesoteloblasts go through a series of cycles, where each cycle is composed of a migration phase and a division phase. Ph-snail1 is expressed during the migration phase, but not during the division phase. We found that as each mesoteloblast division produces one segment's worth of mesoderm, Ph-snail1 expression is linked to both the cell cycle and the segmental production of mesoderm. PMID:22466422

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

    PubMed Central

    KOBAYASHI, Keiya; HORI, Yasutomo; CHIMURA, Syuuichi

    2014-01-01

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

  3. Freshwater Wetlands.

    ERIC Educational Resources Information Center

    Naturescope, 1986

    1986-01-01

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

  4. Snail modulates cell metabolism in MDCK cells

    SciTech Connect

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

    2013-03-22

    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.

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

    PubMed Central

    Lafferty, Kevin D.; Kuris, Armand M.

    2014-01-01

    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

  6. Celss nutrition system utilizing snails

    NASA Astrophysics Data System (ADS)

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

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

  7. Snail sperm production characteristics vary with sperm competition risk

    PubMed Central

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

    1998-01-01

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

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

    USGS Publications Warehouse

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

    2012-01-01

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

  9. Production of apple snail for space diet

    NASA Astrophysics Data System (ADS)

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

    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.

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

    PubMed Central

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  12. Inquiry, Land Snails, and Environmental Factors

    ERIC Educational Resources Information Center

    Barrow, Lloyd H.; Krantz, Patrick D.

    2005-01-01

    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…

  13. 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...

  14. Modeling apple snail population dynamics on the Everglades landscape

    USGS Publications Warehouse

    Darby, Phil; DeAngelis, Donald L.; Romanach, Stephanie; Suir, Kevin J.; Bridevaux, Joshua L.

    2015-01-01

    Comparisons of model output to empirical data indicate the need for more data to better understand, and eventually parameterize, several aspects of snail ecology in support of EverSnail. A primary value of EverSnail is its capacity to describe the relative response of snail abundance to alternative hydrologic scenarios considered for Everglades water management and restoration.

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed Central

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

    2012-01-01

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

  18. Snail Destabilizes Cell Surface Crumbs3a

    PubMed Central

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

    2012-01-01

    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 hours 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

  19. Cysteine-Rich Atrial Secretory Protein from the Snail Achatina achatina: Purification and Structural Characterization

    PubMed Central

    Shabelnikov, Sergey; Kiselev, Artem

    2015-01-01

    Despite extensive studies of cardiac bioactive peptides and their functions in molluscs, soluble proteins expressed in the heart and secreted into the circulation have not yet been reported. In this study, we describe an 18.1-kDa, cysteine-rich atrial secretory protein (CRASP) isolated from the terrestrial snail Achatina achatina that has no detectable sequence similarity to any known protein or nucleotide sequence. CRASP is an acidic, 158-residue, N-glycosylated protein composed of eight alpha-helical segments stabilized with five disulphide bonds. A combination of fold recognition algorithms and ab initio folding predicted that CRASP adopts an all-alpha, right-handed superhelical fold. CRASP is most strongly expressed in the atrium in secretory atrial granular cells, and substantial amounts of CRASP are released from the heart upon nerve stimulation. CRASP is detected in the haemolymph of intact animals at nanomolar concentrations. CRASP is the first secretory protein expressed in molluscan atrium to be reported. We propose that CRASP is an example of a taxonomically restricted gene that might be responsible for adaptations specific for terrestrial pulmonates. PMID:26444993

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2009-07-01

    The behavioural response and survival of marine mud snails and mud shrimp exposed to freshwater and the fungicide chlorothalonil (tetrachloroisophthalonitrile) was investigated. Amphipods were less tolerant of lower salinity than snails, with 50 and 76% survival associated with 5 and 0% seawater in freshwater, respectively. However, 50% of snails displayed a defence mechanism by retracting within their shell when exposed to 70% freshwater. Both species displayed an avoidance to chlorothalonil spiked at >100 ng/g and/or >100 ng/mL in sediments and seawater, respectively. The avoidance response of amphipods was observed along with a reduced swimming ability and increased lipid content. Snails displayed a higher susceptibility to physical stress, with an increased number unable to twist from being on their shell to their foot, and with longer righting time. Behaviour was affected at chlorothalonil concentrations of 0.001-0.01 ng/g and/or ng/mL, with a variability that could be due to degradation by the microbial community. Ascertaining the latter observations requires state-of-the-art chemical analyses. PMID:19731835

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

    SciTech Connect

    Suseno, Heny

    2014-10-24

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

  3. Freshwater Flow Charts - 1995

    SciTech Connect

    Kaiper, G V

    2003-11-21

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

  4. Schistosomes and snails: a molecular encounter

    PubMed Central

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

    2014-01-01

    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

  5. Comparative Phylogenetic Studies on Schistosoma japonicum and Its Snail Intermediate Host Oncomelania hupensis: Origins, Dispersal and Coevolution

    PubMed Central

    Attwood, Stephen W.; Ibaraki, Motomu; Saitoh, Yasuhide; Nihei, Naoko; Janies, Daniel A.

    2015-01-01

    Background Schistosoma japonicum causes major public health problems in China and the Philippines; this parasite, which is transmitted by freshwater snails of the species Oncomelania hupensis, causes the disease intestinal schistosomiasis in humans and cattle. Researchers working on Schistosoma in Africa have described the relationship between the parasites and their snail intermediate hosts as coevolved or even as an evolutionary arms race. In the present study this hypothesis of coevolution is evaluated for S. japonicum and O. hupensis. The origins and radiation of the snails and the parasite across China, and the taxonomic validity of the sub-species of O. hupensis, are also assessed. Methodology/Principal Findings The findings provide no evidence for coevolution between S. japonicum and O. hupensis, and the phylogeographical analysis suggests a heterochronous radiation of the parasites and snails in response to different palaeogeographical and climatic triggers. The results are consistent with a hypothesis of East to West colonisation of China by Oncomelania with a re-invasion of Japan by O. hupensis from China. The Taiwan population of S. japonicum appears to be recently established in comparison with mainland Chinese populations. Conclusions/Significance The snail and parasite populations of the western mountain region of China (Yunnan and Sichuan) appear to have been isolated from Southeast Asian populations since the Pleistocene; this has implications for road and rail links being constructed in the region, which will breach biogeographical barriers between China and Southeast Asia. The results also have implications for the spread of S. japonicum. In the absence of coevolution, the parasite may more readily colonise new snail populations to which it is not locally adapted, or even new intermediate host species; this can facilitate its dispersal into new areas. Additional work is required to assess further the risk of spread of S. japonicum. PMID:26230619

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

    SciTech Connect

    Elder, J.F.; Collins, J.J. )

    1991-01-01

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

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

    PubMed Central

    Wu, Zhong-Dao; Lun, Zhao-Rong

    2013-01-01

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

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

    PubMed

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

    2013-08-01

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

  9. The Snail Resource of the Eastern Berin9 Sea

    E-print Network

    . Japan has harvested snails in the eastern Bering Sea since the early 1970's and there is potentialThe Snail Resource of the Eastern Berin9 Sea and Its Fishery RICHARD A. MaciNTOSH Buccinum sp; potential resources, like east- ern Bering Sea snails, are virtually un- known. Several species of large

  10. Images of Minute Minnesota Land Snails Matt Barthel

    E-print Network

    Nekola, Jeffrey C.

    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

  11. Relationships between nutrient enrichment, pleurocerid snail density and trematode infection rate in streams

    USGS Publications Warehouse

    Ciparis, Serena; Iwanowicz, Deborah D.; Voshell, J. Reese, Jr.

    2013-01-01

    Summary 1. Nutrient enrichment is a widespread environmental problem in freshwater ecosystems. Eutrophic conditions caused by nutrient enrichment may result in a higher prevalence of infection by trematode parasites in host populations, due to greater resource availability for the molluscan first intermediate hosts. 2. This study examined relationships among land use, environmental variables indicating eutrophication, population density of the pleurocerid snail, Leptoxis carinata, and trematode infections. Fifteen study sites were located in streams within the Shenandoah River catchment (Virginia, U.S.A.), where widespread nutrient enrichment has occurred. 3. Snail population density had a weak positive relationship with stream water nutrient concentration. Snail population density also increased as human activities within stream catchments increased, but density did not continue to increase in catchments where anthropogenic disturbance was greatest. 4. Cercariae from five families of trematodes were identified in L. carinata, and infection rate was generally low (<10%). Neither total infection rate nor the infection rate of individual trematode types showed a positive relationship with snail population density, nutrients or land use. 5. There were statistically significant but weak relationships between the prevalence of infection by two trematode families and physical and biological variables. The prevalence of Notocotylidae was positively related to water depth, which may be related to habitat use by definitive hosts. Prevalence of Opecoelidae had a negative relationship with orthophosphate concentration and a polynomial relationship with chlorophyll a concentration. Transmission of Opecoelid trematodes between hosts may be inhibited by eutrophic conditions. 6. Leptoxis carinata appears to be a useful species for monitoring the biological effects of eutrophication and investigating trematode transmission dynamics in lotic systems.

  12. Aquatic Snails, Passive Hosts of Mycobacterium ulcerans

    PubMed Central

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

    2004-01-01

    Accumulative indirect evidence of the epidemiology of Mycobacterium ulcerans infections causing chronic skin ulcers (i.e., Buruli ulcer disease) suggests that the development of this pathogen and its transmission to humans are related predominantly to aquatic environments. We report that snails could transitorily harbor M. ulcerans without offering favorable conditions for its growth and replication. A novel intermediate link in the transmission chain of M. ulcerans becomes likely with predator aquatic insects in addition to phytophage insects. Water bugs, such as Naucoris cimicoides, a potential vector of M. ulcerans, were shown to be infected specifically by this bacterium after feeding on snails experimentally exposed to M. ulcerans. PMID:15466578

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

    PubMed Central

    Wada, Shinichiro; Chiba, Satoshi

    2013-01-01

    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

  14. Mate desertion in the snail kite

    USGS Publications Warehouse

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

    1988-01-01

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

  15. Effect of pond water depth on snail populations and fish-borne zoonotic trematode transmission in juvenile giant gourami (Osphronemus goramy) aquaculture nurseries.

    PubMed

    Thien, P C; Madsen, H; Nga, H T N; Dalsgaard, A; Murrell, K D

    2015-12-01

    Infection with fish-borne zoonotic trematodes (FZT) is an important public health problem in many parts of Southeast Asia. People become infected with FZT when eating raw or undercooked fish that contain the infective stage (metacercariae) of FZT. The parasites require specific freshwater snails as first intermediate host and a variety of fish species, both wild caught and cultured, as second intermediate host. Aquaculture production has grown almost exponentially in SE Asia and in order to produce fish free from FZT metacercariae, it is important to mitigate factors promoting transmission to fish. Here we report results from a cross-sectional study to look at the association between pond depth and infection with FZT in giant gourami nursery ponds. Density of intermediate host snails was positively associated with pond depth (count ratio associated with a 1m increase in pond depth was 10.4 (95% C.L.: 1.61-67.1, p<0.5)) and this may partly explain the higher prevalence and intensity of FZT infection in juvenile fish. High fry stocking density (>200 fry m(-3)) was associated with lower host snail density (count ratio=0.15) than low stocking density (<100 fry m(3)). Ponds stocked with 100-200 fry m(-3) had snail counts 0.76 (95% C.L.: 0.33-1.75, p n.s.) of those in ponds stocked with fry density of <100 fry m(-3). Since density of intermediate snail hosts was associated with FZT transmission to fish, effort should be taken to reduce snail density prior to stocking the fry, but focus should also be on habitats surrounding ponds as transmission may occur through cercariae produced outside ponds and carried into ponds with water pumped into ponds. PMID:26209455

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

    PubMed

    Wahl, Martin

    2008-05-01

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

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

    PubMed

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

    2012-05-01

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

  18. On the Ultrastructure and Function of Rhogocytes from the Pond Snail Lymnaea stagnalis

    PubMed Central

    Kokkinopoulou, Maria; Spiecker, Lisa; Messerschmidt, Claudia; Barbeck, Mike; Ghanaati, Shahram; Landfester, Katharina; Markl, Jürgen

    2015-01-01

    Rhogocytes, also termed “pore cells”, occur as solitary or clustered cells in the connective tissue of gastropod molluscs. Rhogocytes possess an enveloping lamina of extracellular matrix and enigmatic extracellular lacunae bridged by cytoplasmic bars that form 20 nm diaphragmatic slits likely to act as a molecular sieve. Recent papers highlight the embryogenesis and ultrastructure of these cells, and their role in heavy metal detoxification. Rhogocytes are the site of hemocyanin or hemoglobin biosynthesis in gastropods. Based on electron microscopy, we recently proposed a possible pathway of hemoglobin exocytosis through the slit apparatus, and provided molecular evidence of a common phylogenetic origin of molluscan rhogocytes, insect nephrocytes and vertebrate podocytes. However, the previously proposed secretion mode of the respiratory proteins into the hemolymph is still rather hypothetical, and the possible role of rhogocytes in detoxification requires additional data. Although our previous study on rhogocytes of the red-blooded (hemoglobin-containing) freshwater snail Biomphalaria glabrata provided much new information, a disadvantage was that the hemoglobin molecules were not unequivocally defined in the electron microscope. This made it difficult to trace the exocytosis pathway of this protein. Therefore, we have now performed a similar study on the rhogocytes of the blue-blooded (hemocyanin-containing) freshwater snail Lymnaea stagnalis. The intracellular hemocyanin could be identified in the electron microscope, either as individual molecules or as pseudo-crystalline arrays. Based on 3D-electron microscopy, and supplemented by in situ hybridization, immunocytochemistry and stress response experiments, we provide here additional details on the structure and hemocyanin biosynthesis of rhogocytes, and on their response in animals under cadmium and starvation stress. Moreover, we present an advanced model on the release of synthesized hemocyanin molecules through the slit apparatus into the hemolymph, and the uptake of much smaller particles such as cadmium ions from the hemolymph through the slit apparatus into the cytoplasm. PMID:26488403

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

    E-print Network

    Isaacs, Rufus

    to the heads and stalks of plants or fences and enter dormancy (called aestivation). The life cycle is annual Presence of small to medium-sized snails on plants, fences and other structures. Aestivating (inactive and Europe. Large numbers of the vineyard snail aestivating at the top of cereals can clog machinery

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

    E-print Network

    Isaacs, Rufus

    Helicid snail Systematic position Mollusca > Gastropoda > Hygromiidae > Monacha cartusiana (Müller) Global as a prohibited mollusk species by Michigan's plant protection regulations (MDA 2009). Plant hosts A wide variety During the 2004 CAPS survey for exotic snails and slugs, inspections focused on habitats such as refuse

  1. Biology of the Blues: The Snails behind the Ancient Dyes

    NASA Astrophysics Data System (ADS)

    Steinhart, Carol

    2001-11-01

    Three species of marine snails were used in the ancient Mediterranean dye industry. Colorless dye precursors, sulfur-containing indole derivatives, are secreted by the hypobranchial gland of these animals. The several functions of this gland and other aspects of the lives of the snails that are interesting and relevant to the dye industry are described and the chemistry of dye production is summarized.

  2. Microhabitats within Venomous Cone Snails Contain Diverse Actinobacteria? †

    PubMed Central

    Peraud, Olivier; Biggs, Jason S.; Hughen, Ronald W.; Light, Alan R.; Concepcion, Gisela P.; Olivera, Baldomero M.; Schmidt, Eric W.

    2009-01-01

    Actinomycetes can be symbionts in diverse organisms, including both plants and animals. Some actinomycetes benefit their host by producing small molecule secondary metabolites; the resulting symbioses are often developmentally complex. Actinomycetes associated with three cone snails were studied. Cone snails are venomous tropical marine gastropods which have been extensively examined because of their production of peptide-based neurological toxins, but no microbiological studies have been reported on these organisms. A microhabitat approach was used in which dissected tissue from each snail was treated as an individual sample in order to explore bacteria in the tissues separately. Our results revealed a diverse, novel, and highly culturable cone snail-associated actinomycete community, with some isolates showing promising bioactivity in a neurological assay. This suggests that cone snails may represent an underexplored reservoir of novel actinomycetes of potential interest for drug discovery. PMID:19749071

  3. Effects of sewage sludge amendment on snail growth and trace metal transfer in the soil-plant-snail food chain.

    PubMed

    Bourioug, Mohamed; Gimbert, Frédéric; Alaoui-Sehmer, Laurence; Benbrahim, Mohammed; Badot, Pierre-Marie; Alaoui-Sossé, Badr; Aleya, Lotfi

    2015-11-01

    Cu, Zn, Pb, and Cd concentrations in a soil plant (Lactuca sativa) continuum were measured after sewage sludge amendment. The effects of sewage sludge on growth and trace metal bioaccumulation in snails (Cantareus aspersus) were investigated in a laboratory experiment specifically designed to identify contamination sources (e.g., soil and leaves). Application of sewage sludge increased trace metal concentrations in topsoil. However, except Zn, metal concentrations in lettuce leaves did not reflect those in soil. Lettuce leaves were the main source of Zn, Cu, and Cd in exposed snails. Bioaccumulation of Pb suggested its immediate transfer to snails via the soil. No apparent toxic effects of trace metal accumulation were observed in snails. Moreover, snail growth was significantly stimulated at high rates of sludge application. This hormesis effect may be due to the enhanced nutritional content of lettuce leaves exposed to sewage sludge. PMID:26165994

  4. Modeling snail breeding in Bioregenerative Life Support System

    NASA Astrophysics Data System (ADS)

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

    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.

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

    USGS Publications Warehouse

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

    1976-01-01

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

  6. Rare and endangered species: freshwater gastropods of southern New England

    SciTech Connect

    Jokinen, E.H.; Pondick, J.

    1981-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  8. Some aspects of snail ecology in South Africa

    PubMed Central

    de Meillon, B.; Frank, G. H.; Allanson, B. R.

    1958-01-01

    In this paper, the authors present the preliminary results of a recent ecological survey of some rivers in the Transvaal, Union of South Africa. Representative samples of the molluscan fauna of the rivers were collected and chemical analyses of the river waters were carried out. In addition, such characteristics as current speed, temperature, turbidity, biochemical oxygen demand, and amount of oxygen absorbed from potassium permanganate were determined. No evidence was obtained to show that the chemical composition of natural, unpolluted waters plays any part in determining vector snail habitats. Current speed was found to have some effect, bilharzia vector snails not being found in fast-flowing waters. Of the other factors, turbidity was shown to be of some importance, probably because it affects the growth of the algae on which certain snails seem to depend for their proper development, and severe pollution with sewage and industrial wastes also appeared to have an adverse affect on the snail population. PMID:13573112

  9. 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...

  10. The function of dart shooting in helicid snails* Ronald Chase

    E-print Network

    Chase, Ronald

    of snails and slugs in total. It is note- worthy that all the dart-bearing families mate in a simulta- neous, reciprocal manner (Davison et al. 2006). Most of the research on molluscan darts has been done on helicid

  11. Predation of schistosomiasis vector snails by ostracoda (crustacea)

    USGS Publications Warehouse

    Sohn, I.G.; Kornicker, L.S.

    1972-01-01

    An ostracod species of Cypretta is an effective predator in laboratory experiments on 1- to 3-day-old Biomphalaria glabrata, a vector snail of the blood fluke that causes the tropical and subtropical disease schistosomiasis.

  12. Modulation of defensive reflex conditioning in snails by serotonin.

    PubMed

    Andrianov, Vyatcheslav V; Bogodvid, Tatiana K; Deryabina, Irina B; Golovchenko, Aleksandra N; Muranova, Lyudmila N; Tagirova, Roza R; Vinarskaya, Aliya K; Gainutdinov, Khalil L

    2015-01-01

    Highlights Daily injection of serotonin before a training session accelerated defensive reflex conditioning in snails.Daily injection of 5-hydroxytryptophan before a training session in snails with a deficiency of serotonin induced by the "neurotoxic" analog of serotonin 5,7-dihydroxytryptamine, restored the ability of snails to learn.After injection of the "neurotoxic" analogs of serotonin 5,6- and 5,7-dihydroxytryptamine as well as serotonin, depolarization of the membrane and decrease of the threshold potential of premotor interneurons was observed. We studied the role of serotonin in the mechanisms of learning in terrestrial snails. To produce a serotonin deficit, the "neurotoxic" analogs of serotonin, 5,6- or 5,7-dihydroxytryptamine (5,6/5,7-DHT) were used. Injection of 5,6/5,7-DHT was found to disrupt defensive reflex conditioning. Within 2 weeks of neurotoxin application, the ability to learn had recovered. Daily injection of serotonin before a training session accelerated defensive reflex conditioning and daily injections of 5-HTP in snails with a deficiency of serotonin induced by 5,7-DHT restored the snail's ability to learn. We discovered that injections of the neurotoxins 5,6/5,7-DHT as well as serotonin, caused a decrease in the resting and threshold potentials of the premotor interneurons LPa3 and RPa3. PMID:26557063

  13. Modulation of defensive reflex conditioning in snails by serotonin

    PubMed Central

    Andrianov, Vyatcheslav V.; Bogodvid, Tatiana K.; Deryabina, Irina B.; Golovchenko, Aleksandra N.; Muranova, Lyudmila N.; Tagirova, Roza R.; Vinarskaya, Aliya K.; Gainutdinov, Khalil L.

    2015-01-01

    Highlights Daily injection of serotonin before a training session accelerated defensive reflex conditioning in snails.Daily injection of 5-hydroxytryptophan before a training session in snails with a deficiency of serotonin induced by the “neurotoxic” analog of serotonin 5,7-dihydroxytryptamine, restored the ability of snails to learn.After injection of the “neurotoxic” analogs of serotonin 5,6- and 5,7-dihydroxytryptamine as well as serotonin, depolarization of the membrane and decrease of the threshold potential of premotor interneurons was observed. We studied the role of serotonin in the mechanisms of learning in terrestrial snails. To produce a serotonin deficit, the “neurotoxic” analogs of serotonin, 5,6- or 5,7-dihydroxytryptamine (5,6/5,7-DHT) were used. Injection of 5,6/5,7-DHT was found to disrupt defensive reflex conditioning. Within 2 weeks of neurotoxin application, the ability to learn had recovered. Daily injection of serotonin before a training session accelerated defensive reflex conditioning and daily injections of 5-HTP in snails with a deficiency of serotonin induced by 5,7-DHT restored the snail's ability to learn. We discovered that injections of the neurotoxins 5,6/5,7-DHT as well as serotonin, caused a decrease in the resting and threshold potentials of the premotor interneurons LPa3 and RPa3. PMID:26557063

  14. The fossil land and freshwater snails of Gündlkofen (Middle Miocene, Germany).

    PubMed

    Salvador, Rodrigo B

    2014-01-01

    The molluscan fauna from the Middle Miocene (MN 5-6) fossil site of Gündlkofen in southern Germany was first reported by Gall (1980: Mitt. Bayer. Staatssaml. Paläont. hist. Geol., 20, 51-77). He listed 34 continental gastropod species, which were neither figured nor properly described in many cases. Here a revision of his identifications is presented, with a full description of the material and illustration of the best preserved specimens. Following this revision, 20 species are listed for Gündlkofen. Unfortunately, part of the original material was missing and the record of a few species could not be confirmed. The depositional environment seems to have been a temporary water body, like an oxbow lake, surrounded by a humid and warm forest and scrubland. PMID:24872183

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  17. A conserved role for Snail as a potentiator of active transcription

    PubMed Central

    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

    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

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

    PubMed

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

    2013-02-15

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

  19. Functional Changes in the Snail Statocyst System Elicited by Microgravity

    PubMed Central

    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

    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

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

    SciTech Connect

    Khangarot, B.S. )

    1991-06-01

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

  1. Acidification of freshwaters

    SciTech Connect

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

    1987-01-01

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

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

    PubMed

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

    2013-07-01

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

  3. Center forCenter for FreshwaterFreshwater

    E-print Network

    New Hampshire, University of

    accumulation in several aquatic organisms, including several species of zooplankton, snails, and mussels of the volunteer monitors from the New Hampshire Lakes Lay Monitoring Program that participated in the mussel Cyanobacteria (blue-green algae) are among the group of primary producers within an aquatic ecosystem

  4. The use of land snail shells in paleoenvironmental reconstruction

    NASA Astrophysics Data System (ADS)

    Goodfriend, Glenn A.

    Fossil land snail shells constitute a valuable source of paleoenvironmental information for the Quaternary. They can be dated by a variety of methods, including radiocarbon, amino acid racemization and epimerization, and perhaps also {Th}/{U} and ESR. The vast majority of paleoenvironmental studies based on land snail shells have examined the faunal composition of fossil assemblages, from which a variety of paleoenvironmental characteristics such as biome, temperature, and moisture conditions have been reconstructed. Still, there are a number of problems involved in using this approach and these are discussed. Shell morphology has occasionally been used to reconstruct such factors as rainfall and temperature. Stable isotope studies on Quaternary land snails include: analysis of ?18O values of organic matter in the shells, to reconstruct C 4 plant distributions from which rainfall amounts can be inferred, and analysis of ?18O values of shell carbonate, from which trends in the oxygen isotope composition of rainfall can be reconstructed. Stable carbon isotopes of shell carbonate have also been studied but their interpretation is not clear. Amino acid epimerization analysis ( {dalloisoleucine }/{l-isoleucine } ratios) of land snail shells has been used for estimation of paleotemperatures. Some potential uses of land snail shells for paleoenvironmental reconstruction include the study of stable isotopes of H and N, periodic growth lines, and deposits of pedogenic carbonates on the shells.

  5. Lactic acid microflora of the gut of snail Cornu aspersum

    PubMed Central

    Koleva, Zdravka; Dedov, Ivaylo; Kizheva, Joana; Lipovanska, Roxana; Moncheva, Penka; Hristova, Petya

    2014-01-01

    The intestinal lactic acid microflora of the edible snail Cornu aspersum was studied by culture-based methods and was phenotypically and molecularly characterized. The antibacterial activity of lactic acid bacteria (LAB) isolates was investigated. Snails in different stages of development were collected from farms located in several regions of Bulgaria. One hundred twenty-two isolates, belonging to the group of LAB, were characterized morphologically and were divided into four groups. Representative isolates from each morphological type were subjected to phenotypic characterization and molecular identification. The snail gut lactic acid microflora was composed by Enterococcus (17 isolates), Lactococcus (12 isolates), Leuconostoc (7 isolates), Lactobacillus (18 isolates) and Weissella (1 isolate). The species affiliation of Lactococcus lactis (12), Leuconostoc mesenteroides (4) and Lactobacillus plantarum (2) was confirmed by species-specific primers. The Lactobacillus isolates were identified by sequence analysis of 16S rDNA as Lactobacillus brevis (12), L. plantarum (2), Lactobacillus graminis (1) and Lactobacillus curvatus (3). The species L. brevis, L. graminis and L. curvatus were found in snails in a phase of hibernation, whereas L. plantarum was identified both in active and hibernation phases. Antibacterial activity (bacteriocine-like) was shown only by one strain of L. mesentereoides P4/8 against Propionibacterium acnes. The present study showed that the LAB are a component of the microbial communities in the snail digestive system. This is the first report on Lactobacillus strains detected in the gut of C. aspersum. PMID:26019550

  6. New scope on the relationship between rotifers and Biomphalaria alexandrina snails

    PubMed Central

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

    2013-01-01

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

  7. Loss of Snail2 favors skin tumor progression by promoting the recruitment of myeloid progenitors.

    PubMed

    Villarejo, Ana; Molina-Ortiz, Patricia; Montenegro, Yenny; Moreno-Bueno, Gema; Morales, Saleta; Santos, Vanesa; Gridley, Tom; Pérez-Moreno, Mirna A; Peinado, Héctor; Portillo, Francisco; Calés, Carmela; Cano, Amparo

    2015-05-01

    Snail2 is a zinc finger transcription factor involved in driving epithelial to mesenchymal transitions. Snail2 null mice are viable, but display defects in melanogenesis, gametogenesis and hematopoiesis, and are markedly radiosensitive. Here, using mouse genetics, we have studied the contributions of Snail2 to epidermal homeostasis and skin carcinogenesis. Snail2 (-/-) mice presented a defective epidermal terminal differentiation and, unexpectedly, an increase in number, size and malignancy of tumor lesions when subjected to the two-stage mouse skin chemical carcinogenesis protocol, compared with controls. Additionally, tumor lesions from Snail2 (-/-) mice presented a high inflammatory component with an elevated percentage of myeloid precursors in tumor lesions that was further increased in the presence of the anti-inflammatory agent dexamethasone. In vitro studies in Snail2 null keratinocytes showed that loss of Snail2 leads to a decrease in proliferation indicating a non-cell autonomous role for Snail2 in the skin carcinogenic response observed in vivo. Bone marrow (BM) cross-reconstitution assays between Snail2 wild-type and null mice showed that Snail2 absence in the hematopoietic system fully reproduces the tumor behavior of the Snail2 null mice and triggers the accumulation of myeloid precursors in the BM, blood and tumor lesions. These results indicate a new role for Snail2 in preventing myeloid precursors recruitment impairing skin chemical carcinogenesis progression. PMID:25784375

  8. Trematode-induced alterations in shell shape of the mud snail Zeacumantus subcarinatus (Prosobranchia: Batillariidae)

    E-print Network

    Poulin, Robert

    Trematode-induced alterations in shell shape of the mud snail Zeacumantus subcarinatus.poulin@stonebow.otago.ac.nz The shell morphology of mud snails, Zeacumantus subcarinatus, both uninfected and infected by trema- todes shape. Snails harbouring either the echinostomatid Acanthoparyphium sp., or a double infection

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

    E-print Network

    Bustamante, Fabián E.

    polyposis coli (APC) protein initiate most colo- rectal cancers, whereas p53 mutations frequently govern evidence implicates the SNAIL family of transcriptional repressors in cancer development; however, the role of SNAIL in colorectal cancer has not been established. To investigate the importance of SNAIL

  10. ORIGINAL ARTICLE Analysis of snail genes in the crustacean Parhyale hawaiensis

    E-print Network

    Patel, Nipam H.

    ORIGINAL ARTICLE Analysis of snail genes in the crustacean Parhyale hawaiensis: insight into snail crustacean Daphnia magna. These data imply that within arthropoda, snail acquired its role in gastrulation and mesoderm forma- tion in the insect lineage. However, crustaceans are a diverse group with several major

  11. Behavior of technetium in freshwater environments

    SciTech Connect

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

    1984-01-01

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

  12. MTA3 regulates CGB5 and Snail genes in trophoblast

    SciTech Connect

    Chen, Ying; Miyazaki, Jun; Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake ; Nishizawa, Haruki; Kurahashi, Hiroki; Leach, Richard; Department of Obstetrics, Gynecology and Women’s Health, Spectrum Health Medical Group, Grand Rapids, MI 49503 ; Wang, Kai

    2013-04-19

    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.

  13. Effects of pollution on freshwater organisms

    SciTech Connect

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

    1984-06-01

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

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

    USGS Publications Warehouse

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

    2002-01-01

    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.

  15. 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...

  16. Prioritized phenotypic responses to combined predators in a marine snail.

    PubMed

    Bourdeau, Paul E

    2009-06-01

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

  17. Natural parasitic infection of the golden apple snail, Pomacea canaliculata.

    PubMed

    Keawjam, R S; Poonswad, P; Upatham, E S; Banpavichit, S

    1993-03-01

    Golden apple snails, Pomacea canaliculata, were collected once a month during a year to search for their natural parasites. The collections were made at two localities having different ecological environments. Of 576 collected snails from a canal, 176 individuals (30.6%) were infected by three groups of metacercariae. These parasites were amphistome, distome and echinostome metacercariae, which had prevalences of 23.5, 19.5 and 0.5%, respectively. The incidence of infection was highest (68.4% in October) when the snail population was composed of the old, juvenile and young Pomacea. Amphistome metacercariae were found most frequently and echinostome metacercariae the least frequently; both parasites were localized in the foot muscle of the snails and had a Shannon index of zero. The range of amphistomes was 1 to 115 with the mean +/- SD of 1 +/- 2 and 95% CL of 1, 2. Distome metacercariae were found primarily in the heart (range: 1-13), and also in the foot muscle (range: 1-5) and kidney (range: 1-14), with a Shannon index of 0.4. The means +/- SD (with 95% CL) were 3 +/- 4 (95% CL = 1, 5), 3 +/- 4 (95% CL = 2, 4) and 2 +/- 1 (95% CL = 1, 2) for the foot muscle, heart and kidney, respectively. The snails from a pond, another locality, had a low proportion of infected individuals. Of 605 snails, only 24 individuals (4.0%) were infected, with the prevalence of amphistomes, distomes and echinostomes being 0.8, 1.8 and 2.1%, respectively. The incidence of infection for each month was zero or less than 10%, except in May when it was 30.2%. PMID:8362292

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

    PubMed

    Neiman, Maurine; Lively, Curtis M

    2004-10-01

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

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

    PubMed

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

    2006-04-01

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

  20. Snail activation disrupts tissue homeostasis and induces fibrosis in the adult kidney

    PubMed Central

    Boutet, Agnès; De Frutos, Cristina A; Maxwell, Patrick H; Mayol, M José; Romero, J; Nieto, M Angela

    2006-01-01

    During embryonic development, the kidney epithelium originates from cells that undergo a mesenchymal to epithelial transition (MET). The reverse process, epithelium to mesenchyme transition (EMT), has been implicated in epithelial tumor progression and in the fibrosis that leads to end-stage kidney failure. Snail transcription factors induce both natural and pathological EMT, but their implication in renal development and disease is still unclear. We show that Snail genes are downregulated during the MET that occurs during renal development and that this is correlated with Cadherin-16 expression. Snail suppresses Cadherin-16 via the direct repression of the kidney differentiation factor HNF-1?, a novel route by which Snail disrupts epithelial homeostasis. Indeed, Snail activation is sufficient to induce EMT and kidney fibrosis in adult transgenic mice. Significantly, Snail is also activated in patients with renal fibrosis. Thus, Snail expression is suppressed during renal development and it must remain silent in the mature kidney where its aberrant activation leads to fibrosis. PMID:17093497

  1. Sperm in "parhenogenetic" freshwater gastrotrichs.

    PubMed

    Weiss, M J; Levy, D P

    1979-07-20

    Freshwater members of the phylum Gastrotricha have been considered obligate parthenogens. In Lepidodermelia squammata, the species for which there is most evidence for parthenogenesis, sperm have been discovered. This finding will necessitate reexamination of the nature of sexuality and life cycles and of the concept of "species" in freshwater gastrotrichs. PMID:17747043

  2. Although Schmalz described the innervation of the ovotestis in pulmonate snails as early as 1914, no functions have been attributed to it. In H. aspersa, the intestinal nerve branches profusely within the

    E-print Network

    Chase, Ronald

    , no functions have been attributed to it. In H. aspersa, the intestinal nerve branches profusely within of the intestinal nerve. To study the motor consequences of efferent activity, the ovotestis branch was electrically

  3. Food Choice in the Common Snail (Helix Aspersa).

    ERIC Educational Resources Information Center

    Gill, John; Howell, Pauline

    1985-01-01

    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)

  4. SNAILs promote G1 phase in selected cancer cells.

    PubMed

    Wu, Ya-Lan; Xue, Jian-Xin; Zhou, Lin; Deng, Lei; Shang, Yan-Na; Liu, Fang; Mo, Xian-Ming; Lu, You

    2015-11-01

    Cells can acquire a stem-like cell phenotype through epithelial-mesenchymal transition (EMT). However, it is not known which of the stem-like cancer cells are generated by these phenotype transitions. We studied the EMT-inducing roles of SNAILs (the key inducers for the onset of EMT) in selected cancer cells (lung cancer cell line with relatively stable genome), in order to provide more implications for the investigation of EMT-related phenotype transitions in cancer. However, SNAILs fail to induce completed EMT. In addition, we proved that Snail accelerates the early G1 phase whereas Slug accelerates the late G1 phase. Blocking G1 phase is one of the basic conditions for the onset of EMT-related phenotype transitions (e.g., metastasis, acquring stemness). The discovery of this unexpected phenomenon (promoting G1 phase) typically reveals the heterogeneity of cancer cells. The onset of EMT-related phenotype transitions in cancer needs not only the induction and activation of SNAILs, but also some particular heredity alterations (genetic or epigenetic alterations, which cause heterogeneity). The new connection between heredity alteration (heterogeneity) and phenotype transition suggests a novel treatment strategy, the heredity alteration-directed specific target therapy. Further investigations need to be conducted to study the relevant heredity alterations. PMID:26352801

  5. 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...

  6. The snail's love-dart delivers mucus to increase paternity

    E-print Network

    Chase, Ronald

    the spermatophore-receiving organs. While dart shooting probably evolved as the result of sperm competition, a role. Since we also found evidence of early-male sperm precedence, we conclude that snails can optimize; sperm competition; sperm precedence; darts; Cantareus aspersus; Helix aspersa 1. INTRODUCTION In animal

  7. SCAI/AATS/ACC/STS operator and institutional requirements for transcatheter valve repair and replacement, Part III: Pulmonic valve.

    PubMed

    Hijazi, Ziyad M; Ruiz, Carlos E; Zahn, Evan; Ringel, Richard; Aldea, Gabriel S; Bacha, Emile A; Bavaria, Joseph; Bolman, R Morton; Cameron, Duke E; Dean, Larry S; Feldman, Ted; Fullerton, David; Horlick, Eric; Mack, Michael J; Miller, D Craig; Moon, Marc R; Mukherjee, Debabrata; Trento, Alfredo; Tommaso, Carl L

    2015-07-01

    With the evolution of transcatheter valve replacement, an important opportunity has arisen for cardiologists and surgeons to collaborate in identifying the criteria for performing these procedures. Therefore, The Society for Cardiovascular Angiography and Interventions (SCAI), American Association for Thoracic Surgery (AATS), American College of Cardiology (ACC), and The Society of Thoracic Surgeons (STS) have partnered to provide recommendations for institutions to assess their potential for instituting and/or maintaining a transcatheter valve program. This article concerns transcatheter pulmonic valve replacement (tPVR). tPVR procedures are in their infancy with few reports available on which to base an expert consensus statement. Therefore, many of these recommendations are based on expert consensus and the few reports available. As the procedures evolve, technology advances, experience grows, and more data accumulate, there will certainly be a need to update this consensus statement. The writing committee and participating societies believe that the recommendations in this report serve as appropriate requisites. In some ways, these recommendations apply to institutions more than to individuals. There is a strong consensus that these new valve therapies are best performed using a Heart Team approach; thus, these credentialing criteria should be applied at the institutional level. Partnering societies used the ACC's policy on relationships with industry (RWI) and other entities to author this document (http://www.acc.org/guidelines/about-guidelines-and-clinical-documents). To avoid actual, potential, or perceived conflicts of interest due to industry relationships or personal interests, all members of the writing committee, as well as peer reviewers of the document, were asked to disclose all current healthcare-related relationships including those existing 12 months before the initiation of the writing effort. A committee of interventional cardiologists and surgeons was formed to include a majority of members with no relevant RWI and to be led by an interventional cardiology cochair and a surgical cochair with no relevant RWI. Authors with relevant RWI were not permitted to draft or vote on text or recommendations pertaining to their RWI. RWI were reviewed on all conference calls and updated as changes occurred. Author and peer reviewer RWI pertinent to this document are disclosed in the Appendices. In addition, to ensure complete transparency, authors' comprehensive disclosure information (including RWI not pertinent to this document) is available in Appendix AII. The work of the writing committee was supported exclusively by the partnering societies without commercial support. SCAI, AATS, ACC, and STS believe that adherence to these recommendations will maximize the chances that these therapies will become a successful part of the armamentarium for treating valvular heart disease in the United States. In addition, these recommendations will hopefully facilitate optimum quality during the delivery of this therapy, which will be important to the development and successful implementation of future, less invasive approaches to structural heart disease. PMID:25809590

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

    SciTech Connect

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

    1981-01-01

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

  9. Snail and serpinA1 promote tumor progression and predict prognosis in colorectal cancer

    PubMed Central

    Choi, Jin Hwa; Lee, Ja Rang; Kim, Hye Kyung; Jo, Hong-jae; Kim, Hyun Sung; Oh, Nahmgun; Song, Geun Am; Park, Do Youn

    2015-01-01

    The role of Snail and serpin peptidase inhibitor clade A member 1 (serpinA1) in tumorigenesis has been previously identified. However, the exact role and mechanism of these proteins in progression of colorectal cancer (CRC) are controversial. In this study, we investigated the role of Snail and serpinA1 in colorectal cancer (CRC) and examined the mechanisms through which these proteins mediate CRC progression. Immunohistochemical analysis of 528 samples from patients with CRC showed that elevated expression of Snail or serpinA1 was correlated with advanced stage, lymph node metastasis, and poor prognosis. Moreover, we detected a correlation between Snail and serpinA1 expression. Functional studies performed using the CRC cell lines DLD-1 and SW-480 showed that overexpression of Snail or serpinA1 significantly increased CRC cell invasion and migration. Conversely, knockdown of Snail or serpinA1 expression suppressed CRC cell invasion and migration. ChIP analysis revealed that Snail regulated serpinA1 by binding to its promoter. In addition, fibronectin mediated Snail and serpinA1 signaling was involved in CRC cell invasion and migration. Taken together, our data showed that Snail and serpinA1 promoted CRC progression through fibronectin. These findings suggested that Snail and serpinA1 were novel prognostic biomarkers and candidate therapeutic targets in CRC. PMID:26015410

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

    PubMed Central

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

    2015-01-01

    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

  11. YY1 regulates the expression of snail through a distal enhancer

    PubMed Central

    Palmer, Matthew B.; Majumder, Parimal; Cooper, John C.; Yoon, Hyesuk; Wade, Paul A.; Boss, Jeremy M.

    2010-01-01

    Expression of the snail gene is required for the epithelial-mesenchymal transitions that accompany mammalian gastrulation, neural crest migration, and organ formation. Pathological expression of snail contributes to the migratory capacity of invasive tumors, including melanomas. To investigate the mechanism of snail up regulation in human melanoma cells, a conserved enhancer located 3’ of the snail gene was analyzed. An overlapping Ets and YY1 consensus sequence, in addition to a SOX consensus sequence, were required for full enhancer activity. Proteins specifically binding these sequences were detected by EMSA. The Ets/YY1 binding activity was purified by DNA affinity chromatography and identified as YY1. Although ubiquitously expressed, YY1 was bound at the snail 3’ enhancer in vivo in snail-expressing cells but not in cells that did not express snail. Knockdown of YY1 in A375 cells led to decreased snail expression. These results identify a role for YY1 in regulating transcription of snail in melanoma cells through binding to the snail 3’ enhancer. PMID:19208738

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

    USGS Publications Warehouse

    Aguirre-Macedo, Maria Leopoldina; Vidal-Martinez, Victor M.; Lafferty, Kevin D.

    2011-01-01

    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.

  13. Overexpression of Snail in retinal pigment epithelial triggered epithelial–mesenchymal transition

    SciTech Connect

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

    2014-03-28

    Highlights: • First reported overexpression of Snail in RPE cells could directly trigger EMT. • Further confirmed the regulator role of Snail in RPE cells EMT in vitro. • Snail may be a potential therapeutic target to prevent the fibrosis of PVR. - Abstract: 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.

  14. The ecology of freshwater molluscs

    E-print Network

    Thorp, James H.

    2001-01-01

    stream_size 5299 stream_content_type text/plain stream_name The Ecology of Freshwater Molluscs_102.pdf.txt stream_source_info The Ecology of Freshwater Molluscs_102.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset...=UTF-8 102 THE QUARTERLY REVIEW OF BIOLOGY V O L U M E 7 6 THE ECOLOGY OF FRESHWATER MOLLUSCS. By Robert TDillon, Jr. Cambridge and New York: Cam­ bridge University Press. $120.00. xii + 509 p; ill.; index. ISBN: 0-521-35210-X. 2000...

  15. Impact of the age of Biomphalaria alexandrina snails on Schistosoma mansoni transmission: modulation of the genetic outcome and the internal defence system of the snail

    PubMed Central

    Abou-El-Naga, Iman Fathy; Sadaka, Hayam Abd El-Monem; Amer, Eglal Ibrahim; Diab, Iman Hassan; Khedr, Safaa Ibrahim Abd El-Halim

    2015-01-01

    Of the approximately 34 identified Biomphalaria species,Biomphalaria alexandrina represents the intermediate host of Schistosoma mansoni in Egypt. Using parasitological and SOD1 enzyme assay, this study aimed to elucidate the impact of the age of B. alexandrina snails on their genetic variability and internal defence against S. mansoni infection. Susceptible and resistant snails were reared individually for self-reproduction; four subgroups of their progeny were used in experiment. The young susceptible subgroup showed the highest infection rate, the shortest pre-patent period, the highest total cercarial production, the highest mortality rate and the lowest SOD1 activity. Among the young and adult susceptible subgroups, 8% and 26% were found to be resistant, indicating the inheritance of resistance alleles from parents. The adult resistant subgroup, however, contained only resistant snails and showed the highest enzyme activity. The complex interaction between snail age, genetic background and internal defence resulted in great variability in compatibility patterns, with the highest significant difference between young susceptible and adult resistant snails. The results demonstrate that resistance alleles function to a greater degree in adults, with higher SOD1 activity and provide potential implications for Biomphalaria control. The identification of the most susceptible snail age enables determination of the best timing for applying molluscicides. Moreover, adult resistant snails could be beneficial in biological snail control. PMID:26061235

  16. BIODIVERSITY Conservation biogeography of freshwater

    E-print Network

    García-Berthou, Emili

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

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

    USGS Publications Warehouse

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

    2011-01-01

    We compared silver (Ag) bioavailability and toxicity to a freshwater gastropod after exposure to ionic silver (Ag+) and to Ag nanoparticles (Ag NPs) capped with citrate or with humic acid. Silver form, exposure route, and capping agent influence Ag bioaccumulation dynamics in Lymnaea stagnalis. Snails efficiently accumulated Ag from all forms after either aqueous or dietary exposure. For both exposure routes, uptake rates were faster for Ag+ than for Ag NPs. Snails efficiently assimilated Ag from Ag NPs mixed with diatoms (assimilation efficiency (AE) ranged from 49 to 58%) and from diatoms pre-exposed to Ag+ (AE of 73%). In the diet, Ag NPs damaged digestion. Snails ate less and inefficiently processed the ingested food, which adversely impacted their growth. Loss rates of Ag were faster after waterborne exposure to Ag NPs than after exposure to dissolved Ag+. Once Ag was taken up from diet, whether from Ag+ or Ag NPs, Ag was lost extremely slowly. Large Ag body concentrations are thus expected in L. stagnalis after dietborne exposures, especially to citrate-capped Ag NPs. Ingestion of Ag associated with particulate materials appears as the most important vector of uptake. Nanosilver exposure from food might trigger important environmental risks.

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

    PubMed Central

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

    2014-01-01

    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

  19. Mercury residues in south Florida apple snails (Pomacea paludosa)

    SciTech Connect

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

    1997-05-01

    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.

  20. Mercury residues in south Florida apple snails (Pomacea paludosa)

    USGS Publications Warehouse

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

    1997-01-01

    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.

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  3. Function of insulin in snail brain in associative learning.

    PubMed

    Kojima, S; Sunada, H; Mita, K; Sakakibara, M; Lukowiak, K; Ito, E

    2015-10-01

    Insulin is well known as a hormone regulating glucose homeostasis across phyla. Although there are insulin-independent mechanisms for glucose uptake in the mammalian brain, which had contributed to a perception of the brain as an insulin-insensitive organ for decades, the finding of insulin and its receptors in the brain revolutionized the concept of insulin signaling in the brain. However, insulin's role in brain functions, such as cognition, attention, and memory, remains unknown. Studies using invertebrates with their open blood-vascular system have the promise of promoting a better understanding of the role played by insulin in mediating/modulating cognitive functions. In this review, the relationship between insulin and its impact on long-term memory (LTM) is discussed particularly in snails. The pond snail Lymnaea stagnalis has the ability to undergo conditioned taste aversion (CTA), that is, it associatively learns and forms LTM not to respond with a feeding response to a food that normally elicits a robust feeding response. We show that molluscan insulin-related peptides are up-regulated in snails exhibiting CTA-LTM and play a key role in the causal neural basis of CTA-LTM. We also survey the relevant literature of the roles played by insulin in learning and memory in other phyla. PMID:26233474

  4. A Population Growth Trend Analysis for Neotricula aperta, the Snail Intermediate Host of Schistosoma mekongi, after Construction of the Pak-Mun Dam

    PubMed Central

    Attwood, Stephen W.; Upatham, E. Suchart

    2013-01-01

    Background The Pak-Mun dam is a controversial hydro-power project on the Mun River in Northeast Thailand. The dam is sited in a habitat of the freshwater snail Neotricula aperta, which is the intermediate host for the parasitic blood-fluke Schistosoma mekongi causing Mekong schistosomiasis in humans in Cambodia and Laos. Few data are available which can be used to assess the effects of water resource development on N. aperta. The aim of this study was to obtain data and to analyze the possible impact of the dam on N. aperta population growth. Methodology/Principal Findings Estimated population densities were recorded for an N. aperta population in the Mun River 27 km upstream of Pak-Mun, from 1990 to 2011. The Pak-Mul dam began to operate in 1994. Population growth was modeled using a linear mixed model expression of a modified Gompertz stochastic state-space exponential growth model. The N. aperta population was found to be quite stable, with the estimated growth parameter not significantly different from zero. Nevertheless, some marked changes in snail population density were observed which were coincident with changes in dam operation policy. Conclusions/Significance The study found that there has been no marked increase in N. aperta population growth following operation of the Pak-Mun dam. The analysis did indicate a large and statistically significant increase in population density immediately after the dam came into operation; however, this increase was not persistent. The study has provided the first vital baseline data on N. aperta population behavior near to the Pak-Mun dam and suggests that the operation policy of the dam may have an impact on snail population density. Nevertheless, additional studies are required for other N. aperta populations in the Mun River and for an extended time series, to confirm or refine the findings of this work. PMID:24244775

  5. 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...

  6. Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities

    PubMed Central

    Brogan, William R.; Relyea, Rick A.

    2015-01-01

    Understanding how ecological interactions mitigate the impacts of perturbations such as pesticides in biological communities is an important basic and applied question for ecologists. In aquatic ecosystems, new evidence from microcosm experiments suggests that submerged macrophytes can buffer cladocerans from pulse exposures to the widely used insecticide malathion, and that mitigation increases with macrophyte density. However, whether these results scale up to more complex aquatic communities where ecological interactions such as competition can alter toxicity is unknown. Further, macrophyte abilities to mitigate different insecticide exposure scenarios (i.e. single versus repeated pulses) have never been tested. To address these gaps, we performed a factorial mesocosm experiment examining the influence of four macrophyte treatments (0, 10, 50, or 100 Elodea Canadensis shoots planted per mesocosm) crossed with three malathion exposure scenarios (no insecticide, single pulse, repeated pulses) on aquatic communities containing zooplankton, phytoplankton, periphyton, two snail species, and larval amphibians. In the absence of macrophytes, single malathion pulses caused short-term declines in cladoceran abundance followed by their rapid recovery, which precluded any indirect effects (i.e. trophic cascades). However, repeated malathion pulses caused cladoceran extinctions, resulting in persistent phytoplankton blooms and reduced abundance of one snail species. In contrast, with macrophytes present, even at low density, malathion had no effect on any taxa. We also discovered novel effects of macrophytes on the benthic food web. In the two highest macrophyte treatments, we observed trends of reduced periphyton biomass, decreased abundance of one snail species, and decreased amphibian time to and mass at metamorphosis. To our knowledge, this is the first evidence of negative submerged macrophyte effects on amphibians, a taxa of global conservation concern. Our findings suggest that facilitating macrophytes could be an important strategy for buffering freshwater communities from insecticides, though consideration of their impacts on animal species is necessary. PMID:25978686

  7. The Freshwater Bivalve Mollusca (Unionidae, Sphaeriidae, Corbiculidae)

    E-print Network

    Georgia, University of

    SRQ-NERp·3 The Freshwater Bivalve Mollusca (Unionidae, Sphaeriidae, Corbiculidae) of the Savannah Ecology Laboratory #12;THE FRESHWATER BIVALVE MOLLUSCA (UNIONIDAE, SPHAERIIDAE, CORBICULIDAEj STUDY AREA " 1 LIST OF BIVALVE MOLLUSKS AT THE SAVANNAH RIVER PLANT

  8. The Role of Molluscan Insulin-Related Peptides in Regulating the Phenotypic Plasticity and Response to Predators in Snails

    E-print Network

    jar with 500 mL of dechlorinated tap water; each jar will represent an experimental unit (n=8 units (Salice and Plautz, 2011). For example, in many taxa ranging from tadpoles to fish to snails, interactions water with crushed snails to stimulate a predator response in snails (Physa acuta; Salice and Plautz

  9. 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/...

  10. Foraging Strategy of the Giant Rams-Horn Snail, Marisa cornuarietis: An Interpretive Model

    E-print Network

    Willig, Michael

    and physi- In general, optimal foraging behavior is hypothesized to ological differences among individualsForaging Strategy of the Giant Rams-Horn Snail, Marisa cornuarietis: An Interpretive Model Ö. K #12;OIKOS 72: 333-342. Copenhagen 1995 Foraging strategy of the giant rams-horn snail, Marisa

  11. Studies on the molluscicidal activity of Agave angustifolia and Pittosporum tobira on schistosomiasis transmitting snails.

    PubMed

    Ibrahim, Abdalla M; Abdel-Gawad, Mahfouz M; El-Nahas, Hanan A; Osman, Nadia S

    2015-04-01

    In the search for new molluscicidal plants for controlling the snail vectors of schistosomiasis, laboratory evaluation was made to assess the molluscicidal activity of Agave angustifolia and Pittosporum tobira plants against Biomphalaria alexandrina snails. Results indicated that both plants have promising molluscicidal activity as the LC90 of the dry powder of both plants was 120 ppm. Both plants showed marked cercaricidal and miracidicidal potencies against S. mansoni larvae. The LC90 of both plants (120 ppm) killed most B. alexandrina eggs within 24 h of exposure. The sub-lethal concentrations of both plants markedly suppressed the survival rate of B. alexandrina snails and the mortality increased with increasing the concentrations and the exposure period up to 10 successive weeks. The accumulative toxic effect of these concentrations was continuous during the recovery period. Also, the reproductive rates of exposed snails were greatly affected even through the recovery period. This depression in reproductive ability of snails was accompanied by histological damage in the hermaphrodite glands of exposed snails. Meanwhile, the growth of snails was estimated weekly and it showed great inhibition in exposed snails comparing with the control ones. PMID:26012228

  12. A literature database on the mating behavior of stylommatophoran land snails Angus Davison1

    E-print Network

    Davison, Angus

    A literature database on the mating behavior of stylommatophoran land snails and slugs* Angus and slugs generally mate by shell-mounting or face-to-face. Although phylogenetic evidence suggests gastropods, therefore, stylommatophoran land snails and slugs could be particularly useful in trying

  13. The non-native faucet snail (Bithynia tentaculata) makes the leap to Lake Superior

    EPA Science Inventory

    The European-origin faucet snail (Bithynia tentaculata) has been present in the lower Great Lakes since the late 1800s but only very recently reached Lake Superior. Surveys from 2011 through 2013 found faucet snail to be abundant and wide-spread in the St. Louis River Estuary wi...

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

    USGS Publications Warehouse

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

    2008-01-01

    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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  16. SURVEY OF ENDANGERED TREE SNAILS ON NAVY-OWNED LAND IN GUAM

    E-print Network

    Mcilwain, Jenny

    that are limited in geographic distribution to volcanic high islands of the tropical Pacific, ranging from Applications International Corporation (SAIC), Guam Office2 INTRODUCTION The land snail faunas on islands by relatively few families. Despite this diversity, native land snail faunas of the Pacific islands are composed

  17. Sex ratio and susceptibility of the golden apple snail, Pomacea canaliculata.

    PubMed

    Banpavichit, S; Keawjam, R S; Upatham, E S

    1994-06-01

    Golden apple snails, Pomacea canaliculata, were collected at two localities having different ecological environments. In both canal and pond, P. canaliculata males were found more than females during the dry season (summer and winter). In the canal, the male snails were highest in number (86.67%) in May. When rain started, they began decreasing and were lowest at 33.33% in August. Of 575 snails collected, 30.6% were infected by one or more of the three groups of amphistome, distome and echinostome metacercariae. There were two high peaks of infection in April and October, as 60.7% and 68.4%, respectively, during which there were more males than females. The average number of parasites per snail which was highest at 54 was found in the medium-sized males (25 out of 35 males) in October. The number of parasites per snail was significantly correlated with the collected males (p < 0.01), but such relationship was not occurred with the females. Of the females, only the large-sized individuals were infected. In the pond, the female snails were present in much greater numbers than the males during the reproductive time (June-September). The females were highest (94.23%) in August. Only 24 (4.0%) of 605 snails were infected; most of the infected snails were large. PMID:7855663

  18. Inhabitants of the Fresh-Water Community.

    ERIC Educational Resources Information Center

    Jorgensen, Joseph; Schroeder, Marlene

    This learner's guide is designed to assist middle school students in studying freshwater organisms. Following a brief introduction to freshwater ecology, simple line drawings facilitate the identification of plants and animals common to Florida's freshwater ecosystems. Emphasis of the short text which accompanies each illustration is upon the…

  19. The Anguillidae, or the Freshwater Eels

    E-print Network

    Limburg, Karin E.

    1 The Anguillidae, or the Freshwater Eels K. Limburg, Fisheries Science Lecture Notes FishBase.org Anguillids, or freshwater eels 1 genus (Anguilla), 15 species European eel, Anguilla anguilla American eel, ABase.org Tesch, 1977 In contrast with salmons, freshwater eels are catadromous - although not all of them

  20. Freshwater Ecology. LC Science Tracer Bullet.

    ERIC Educational Resources Information Center

    Niskern, Diana, Comp.

    Freshwater ecosystems include lakes, ponds, streams, rivers, and certain types of wetlands. This literature and resources guide is not intended to be a comprehensive bibliography on freshwater ecology; the guide is designed--as the name of the series implies--to put the reader or student "on target." Other literature guides related to freshwater

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

    SciTech Connect

    Scherbakov, Alexander M.; Stefanova, Lidia B.; Sorokin, Danila V.; Semina, Svetlana E.; Berstein, Lev M.; Krasil’nikov, Mikhail A.

    2013-12-10

    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.

  2. Wnt signaling through Snail1 and Zeb1 regulates bone metastasis in lung cancer

    PubMed Central

    Yang, Xinghai; Li, Lei; Huang, Quan; Xu, Wei; Cai, Xiaopan; Zhang, Jishen; Yan, Wangjun; Song, Dianwen; Liu, Tielong; Zhou, Wang; Li, Zhenxi; Yang, Cheng; Dang, Yongyan; Xiao, Jianru

    2015-01-01

    Wnt-?-catenin signaling participates in the epithelial-mesenchymal transition (EMT) in a variety of cancers; however, its role in lung cancer induced bone metastasis and the underlying mechanisms remain unclear. Here, we demonstrate that ?-catenin, Snail1 and Zeb1 were significantly upregulated in bone metastasis tissues from human and mouse compared with the normal controls. E-cadherin expression is negatively regulated by Zeb1, Snail1 and ?-catenin during bone metastasis tissues induced by lung cancer. Knocking down Zeb1 and Snail1 in lung cancer cell lines showed increased E-cadherin mRNA expression and less invasion compared with the original cell lines. In addition, ?-catenin knockdown led to the increase of E-cadherin and the decrease of Zeb1 and Snail1, which in turn inhibited the invasive properties of lung cancer. Our results demonstrated that Wnt signaling through Snail1 and Zeb1 regulates bone metastasis in lung cancer. PMID:25973312

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

    PubMed Central

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

    2009-01-01

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

  4. Snail blocks the cell cycle and confers resistance to cell death

    PubMed Central

    Vega, Sonia; Morales, Aixa V.; Ocaña, Oscar H.; Valdés, Francisco; Fabregat, Isabel; Nieto, M. Angela

    2004-01-01

    The Snail zinc-finger transcription factors trigger epithelial-mesenchymal transitions (EMTs), endowing epithelial cells with migratory and invasive properties during both embryonic development and tumor progression. During EMT, Snail provokes the loss of epithelial markers, as well as changes in cell shape and the expression of mesenchymal markers. Here, we show that in addition to inducing dramatic phenotypic alterations, Snail attenuates the cell cycle and confers resistance to cell death induced by the withdrawal of survival factors and by pro-apoptotic signals. Hence, Snail favors changes in cell shape versus cell division, indicating that with respect to oncogenesis, although a deregulation/increase in proliferation is crucial for tumor formation and growth, this may not be so for tumor malignization. Finally, the resistance to cell death conferred by Snail provides a selective advantage to embryonic cells to migrate and colonize distant territories, and to malignant cells to separate from the primary tumor, invade, and form metastasis. PMID:15155580

  5. Use of a saponin based molluscicide to control Pomacea canaliculata snails in Southern Brazil.

    PubMed

    San Martíns, R; Gelmi, Claudio; de Oliveira, Jaime Vargas; Galo, José Luis; Pranto, Honorio

    2009-10-01

    Pomacea canaliculata snails pose a severe problem to direct seeded rice cultivated in Southern Brazil. Control of this snail is nowadays performed with toxic chemicals such as copper sulfate and fungicides such as fentin. A novel natural molluscicide based on alkali modified quinoa (Chenopodium quinoa) saponins was tested under laboratory conditions. Snails were collected in rice fields close to Porto Alegre (State of Rio Grande do Sul) and in Brusque (State of Santa Catarina, 400 km north of Porto Alegre). In Santa Catarina the product was very effective, while in Porto Alegre it had no effect. This unexpected behavior was probably due to the respiratory habits of the snails under different contents of dissolved oxygen in the water. Near Porto Alegre the water used in rice fields is heavily polluted, with dissolved oxygen levels of 1-2 ppm, and the snails rely primarily on their siphon and lungs to breathe. Since saponin control is probably due to an interaction between saponins with the sterols present in the cell walls in the gills, no control was observed. By contrast, in Santa Catarina the dissolved oxygen level of the water is 5-6 ppm, and the snails remain mostly underwater, breathing with their gills. In this case the snails died within 24 h at a dose of 20 and 30 ppm of product. To test this observation, snails grown in polluted waters were forced to remain underwater in saponin solutions and water (control) preventing the use of their siphon to breathe. The snails exposed to saponin solutions died, while the control snails survived, indicating that they were still able to use their gills to breathe. These results indicate that the use of the saponin product is limited to rice fields not irrigated with heavily polluted waters. PMID:19911565

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

    PubMed

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

    2012-01-01

    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

  7. Snail1 expression in colorectal cancer and its correlation with clinical and pathological parameters

    PubMed Central

    2013-01-01

    Background Snail1 is a transcription regulator of E-cadherin. The loss of E-cadherin seems to be a crucial step in the process of Epithelial-mesenchymal transition (EMT). EMT initiates invasion and proliferation in many tumours. Overexpression of Snail1 is known to be associated with poor outcome in several solid tumours. The aim of this study was to analyse its expression profile and prognostic significance in colorectal cancer. Methods Tissue microarrays (TMA) containing paraffin-embedded primary colorectal cancer (CRC) tissue samples from 251 patients were used in this study. The expression of Snail1 and E-cadherin was assessed by immunohistochemistry in different tumour compartments, corresponding lymph node metastases and normal colonic mucosa. Intensity of staining was classified according to the Remmele score (standardized scoring system) as well as the semiquantitative score established by Blechschmidt et al. Results Snail1 expression was observed in 76% of the CRC. Loss of E-cadherin was noted in 87% of the CRC. Snail1 positive tumours were significantly correlated with Snail1 positive lymph node metastases (p=0.03). There was no significant correlation between loss of E-cadherin and Snail1 expression, or between N-stage or grading and Snail1 expression. Kaplan-Meier survival analysis identified no prognostic impact of Snail1 expression on overall survival. Conclusion Snail1 expression was detectable in most of the CRC but showed no significant association with E-cadherin loss, clinical pathological characteristics or overall survival. The observed loss of E-cadherin could be explained by effects of other important EMT pathways, such as the Wnt-signalling cascade. PMID:23522088

  8. Cable Bacteria in Freshwater Sediments

    PubMed Central

    Kristiansen, Michael; Frederiksen, Rasmus B.; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage. PMID:26116678

  9. Cable Bacteria in Freshwater Sediments.

    PubMed

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-09-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage. PMID:26116678

  10. A flavonol present in cocoa [(-)epicatechin] enhances snail memory.

    PubMed

    Fruson, Lee; Dalesman, Sarah; Lukowiak, Ken

    2012-10-15

    Dietary consumption of flavonoids (plant phytochemicals) may improve memory and neuro-cognitive performance, though the mechanism is poorly understood. Previous work has assessed cognitive effects in vertebrates; here we assess the suitability of Lymnaea stagnalis as an invertebrate model to elucidate the effects of flavonoids on cognition. (-)Epicatechin (epi) is a flavonoid present in cocoa, green tea and red wine. We studied its effects on basic snail behaviours (aerial respiration and locomotion), long-term memory (LTM) formation and memory extinction of operantly conditioned aerial respiratory behaviour. We found no significant effect of epi exposure (15 mg l(-1)) on either locomotion or aerial respiration. However, when snails were operantly conditioned in epi for a single 0.5 h training session, which typically results in memory lasting ~3 h, they formed LTM lasting at least 24 h. Snails exposed to epi also showed significantly increased resistance to extinction, consistent with the hypothesis that epi induces a more persistent LTM. Thus training in epi facilitates LTM formation and results in a more persistent and stronger memory. Previous work has indicated that memory-enhancing stressors (predator kairomones and KCl) act via sensory input from the osphradium and are dependent on a serotonergic (5-HT) signalling pathway. Here we found that the effects of epi on LTM were independent of osphradial input and 5-HT, demonstrating that an alternative mechanism of memory enhancement exists in L. stagnalis. Our data are consistent with the notion that dietary sources of epi can improve cognitive abilities, and that L. stagnalis is a suitable model with which to elucidate neuronal mechanisms. PMID:23014569

  11. High Incidence of Noonan Syndrome Features Including Short Stature and Pulmonic Stenosis in Patients carrying NF1 Missense Mutations Affecting p.Arg1809: Genotype-Phenotype Correlation.

    PubMed

    Rojnueangnit, Kitiwan; Xie, Jing; Gomes, Alicia; Sharp, Angela; Callens, Tom; Chen, Yunjia; Liu, Ying; Cochran, Meagan; Abbott, Mary-Alice; Atkin, Joan; Babovic-Vuksanovic, Dusica; Barnett, Christopher P; Crenshaw, Melissa; Bartholomew, Dennis W; Basel, Lina; Bellus, Gary; Ben-Shachar, Shay; Bialer, Martin G; Bick, David; Blumberg, Bruce; Cortes, Fanny; David, Karen L; Destree, Anne; Duat-Rodriguez, Anna; Earl, Dawn; Escobar, Luis; Eswara, Marthanda; Ezquieta, Begona; Frayling, Ian M; Frydman, Moshe; Gardner, Kathy; Gripp, Karen W; Hernández-Chico, Concepcion; Heyrman, Kurt; Ibrahim, Jennifer; Janssens, Sandra; Keena, Beth A; Llano-Rivas, Isabel; Leppig, Kathy; McDonald, Marie; Misra, Vinod K; Mulbury, Jennifer; Narayanan, Vinodh; Orenstein, Naama; Galvin-Parton, Patricia; Pedro, Helio; Pivnick, Eniko K; Powell, Cynthia M; Randolph, Linda; Raskin, Salmo; Rosell, Jordi; Rubin, Karol; Seashore, Margretta; Schaaf, Christian P; Scheuerle, Angela; Schultz, Meredith; Schorry, Elizabeth; Schnur, Rhonda; Siqveland, Elizabeth; Tkachuk, Amanda; Tonsgard, James; Upadhyaya, Meena; Verma, Ishwar C; Wallace, Stephanie; Williams, Charles; Zackai, Elaine; Zonana, Jonathan; Lazaro, Conxi; Claes, Kathleen; Korf, Bruce; Martin, Yolanda; Legius, Eric; Messiaen, Ludwine

    2015-11-01

    Neurofibromatosis type 1 (NF1) is one of the most frequent genetic disorders, affecting 1:3,000 worldwide. Identification of genotype-phenotype correlations is challenging because of the wide range clinical variability, the progressive nature of the disorder, and extreme diversity of the mutational spectrum. We report 136 individuals with a distinct phenotype carrying one of five different NF1 missense mutations affecting p.Arg1809. Patients presented with multiple café-au-lait macules (CALM) with or without freckling and Lisch nodules, but no externally visible plexiform neurofibromas or clear cutaneous neurofibromas were found. About 25% of the individuals had Noonan-like features. Pulmonic stenosis and short stature were significantly more prevalent compared with classic cohorts (P < 0.0001). Developmental delays and/or learning disabilities were reported in over 50% of patients. Melanocytes cultured from a CALM in a segmental NF1-patient showed two different somatic NF1 mutations, p.Arg1809Cys and a multi-exon deletion, providing genetic evidence that p.Arg1809Cys is a loss-of-function mutation in the melanocytes and causes a pigmentary phenotype. Constitutional missense mutations at p.Arg1809 affect 1.23% of unrelated NF1 probands in the UAB cohort, therefore this specific NF1 genotype-phenotype correlation will affect counseling and management of a significant number of patients. PMID:26178382

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

    SciTech Connect

    Russell, L.K.; DeHaven, J.I.; Botts, R.P.

    1981-05-01

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

  13. Toxicity of botanical insecticides on golden apple snail (Pomacea canaliculata).

    PubMed

    Ruamthum, W; Visetson, S; Milne, J R; Bullangpoti, V

    2010-01-01

    The molluscicidal activity of crude extracts from five highly potential plants, Annona squamosa seed, Nerium indicum Leaves, Stemona tuberose root, Cyperus rotundus corm and Derris elliptica root was assessed to Pomacea canaliculata. D. elliptica root and C. rotundus corm extracts showed the highest toxicity against 3-month old snails which have LC50 as 23.68 +/- 2.96 mg/l and 133.20 +/- 7.94 mg/l, respectively. The C. rotundus corm extracts were chosen for detoxification enzyme in vivo assay which shows esterase and glutathione S-transferase activity in stomach, intestinal tracts and digestive glands of survival treated P. canaliculata were inhibited. PMID:21542482

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

    PubMed Central

    Yusa, Yoichi

    2007-01-01

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

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

    PubMed Central

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

    2014-01-01

    SUMMARY 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 post-translational regulation of SNAIL, we performed a luciferase-based genome-wide E3 ligase siRNA library screen and identified SCF-FBXO11 as an important E3 which targets SNAIL for ubiquitylation and degradation. Furthermore, we discovered that SNAIL degradation by FBXO11 is dependent on Serine-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 post-translational regulation of EMT and cancer metastasis. PMID:25203322

  16. Imposex in the golden apple snail Pomacea canaliculata in Taiwan.

    PubMed

    Liu, Wen-Hui; Chiu, Yuh-Wen; Huang, Da-Ji; Liu, Ming-Yie; Lee, Ching-Chang; Liu, Li-Lian

    2006-12-01

    The golden apple snail Pomacea canaliculata (Lamarck, 1822) was introduced into Taiwan intentionally in the early 1980s and has become a recurring pest that seriously threatens aquatic crops. In this study, a field description of imposex with a developed penis sheath and penis in female golden apple snails from crop/domestic wastewater drainage sites and a six-order river is presented for the first time. Based on the five field collections and the aquarium group, the vas deferens sequence (VDS) of P. canaliculata in imposex development was categorized into four stages, i.e., stage 0: without male genital system; stage 1: with rudimentary penis; stage 2: with rudimentary penis and penis sheath; and stage 3: the rudimentary penis developing into penis pouch and penis. The VDS indices varied between 1.07 and 2.82 and were lowest in the aquarium group and Yuanlin2. Regarding the severity of imposex, the aquarium group was less pronounced, as illustrated by the length of penis sheath and penis length, than the field collections (p<0.05). In respect of the penis length, males of the most imposex-affected site were up to 15% shorter than that of the aquarium group. Negative correlations between male penis length and female imposex characters (i.e., penis length and penis sheath length) were also observed. PMID:17023028

  17. Characterizations of cholinesterases in golden apple snail (Pomacea canaliculata).

    PubMed

    Zou, Xiang-Hui; Xie, Heidi Qun-Hui; Zha, Guang-Cai; Chen, Vicky Ping; Sun, Yan-Jie; Zheng, Yu-Zhong; Tsim, Karl Wah-Keung; Dong, Tina Ting-Xia; Choi, Roy Chi-Yan; Luk, Wilson Kin-Wai

    2014-07-01

    Cholinesterases (ChEs) have been identified in vertebrates and invertebrates. Inhibition of ChE activity in invertebrates, such as bivalve molluscs, has been used to evaluate the exposure of organophosphates, carbamate pesticides, and heavy metals in the marine system. The golden apple snail (Pomacea canaliculata) is considered as one of the worst invasive alien species harmful to rice and other crops. The ChE(s) in this animal, which has been found recently, but poorly characterized thus far, could serve as biomarker(s) for environmental surveillance as well as a potential target for the pest control. In this study, the tissue distribution, substrate preference, sensitivity to ChE inhibitors, and molecular species of ChEs in P. canaliculata were investigated. It was found that the activities of both AChE and BChE were present in all test tissues. The intestine had the most abundant ChE activities. Both enzymes had fair activities in the head, kidney, and gills. The BChE activity was more sensitive to tetra-isopropylpyrophosphoramide (iso-OMPA) than the AChE. Only one BChE molecular species, 5.8S, was found in the intestine and head, whereas two AChE species, 5.8S and 11.6S, were found there. We propose that intestine ChEs of this snail may be potential biomarkers for manipulating pollutions. PMID:24217797

  18. Bacterial induction of Snail1 contributes to blood-brain barrier disruption

    PubMed Central

    Kim, Brandon J.; Hancock, Bryan M.; Bermudez, Andres; Cid, Natasha Del; Reyes, Efren; van Sorge, Nina M.; Lauth, Xavier; Smurthwaite, Cameron A.; Hilton, Brett J.; Stotland, Aleksandr; Banerjee, Anirban; Buchanan, John; Wolkowicz, Roland; Traver, David; Doran, Kelly S.

    2015-01-01

    Bacterial meningitis is a serious infection of the CNS that results when blood-borne bacteria are able to cross the blood-brain barrier (BBB). Group B Streptococcus (GBS) is the leading cause of neonatal meningitis; however, the molecular mechanisms that regulate bacterial BBB disruption and penetration are not well understood. Here, we found that infection of human brain microvascular endothelial cells (hBMECs) with GBS and other meningeal pathogens results in the induction of host transcriptional repressor Snail1, which impedes expression of tight junction genes. Moreover, GBS infection also induced Snail1 expression in murine and zebrafish models. Tight junction components ZO-1, claudin 5, and occludin were decreased at both the transcript and protein levels in hBMECs following GBS infection, and this repression was dependent on Snail1 induction. Bacteria-independent Snail1 expression was sufficient to facilitate tight junction disruption, promoting BBB permeability to allow bacterial passage. GBS induction of Snail1 expression was dependent on the ERK1/2/MAPK signaling cascade and bacterial cell wall components. Finally, overexpression of a dominant-negative Snail1 homolog in zebrafish elevated transcription of tight junction protein–encoding genes and increased zebrafish survival in response to GBS challenge. Taken together, our data support a Snail1-dependent mechanism of BBB disruption and penetration by meningeal pathogens. PMID:25961453

  19. The prevalence of Fasciola hepatica in its snail intermediate host determined by DNA probe assay.

    PubMed

    Kaplan, R M; Dame, J B; Reddy, G R; Courtney, C H

    1997-12-01

    Accurate snail intermediate host infection prevalence data have the potential to be extremely useful in determining seasonal transmission dynamics of Fasciola hepatica. Because the microscopic techniques currently used lack the sensitivity and specificity necessary to obtain meaningful infection prevalence data, we developed a highly accurate and efficient DNA probe assay. The assay has a sensitivity of 100%, a specificity of > 99%, easily detects a single miracidia and does not cross-hybridize with DNA of Fascioloides magna, Paramphistomum liorchis or Heterobilharzia americana, trematodes that share the same intermediate host and enzootic range as Fasciola hepatica. Using this assay, we determined the prevalence of F. hepatica in its snail intermediate host, Fossaria cubensis, during the second year of a 2-year study on the epizootiology of Fasciola hepatica in Florida. The overall infection prevalence of snails assayed in this study (n = 5246) was 1.5% and ranged from 0.1% to 3.1% for individual cattle ranches. Additionally, infection prevalence differed significantly for successive size groupings of snails, varying from 0% for 1-mm snails to 18.5% for 9- and 10-mm snails. The accuracy and efficiency of the DNA probe assay reported here for determining snail infection prevalence offers an inexpensive alternative to tracer animal studies for determining the epizootiology of F. hepatica. PMID:9467746

  20. Comparative toxicity of Paraquat herbicide and some plant extracts in Lymnaea natalensis snails.

    PubMed

    Bakry, Fayez A; Eleiwa, Mona E; Taha, Samir A; Ismil, Somya M

    2016-01-01

    Paraquat has been shown to be a highly toxic compound for humans and animals, and many cases of acute poisoning and death have been reported over the past few decades. The present study was undertaken to evaluate comprehensively herbicides (Paraquat) and some plant extracts to biochemical aspects of Lymnaea natalensis snails. It was found that the exposure of L. natalensis to Paraquat and plant extracts led to a significant reduction in the infectivity of Fasciola gigantica miracidia to the snail. The glucose level in hemolymph of exposed snails was elevated, while the glycogen showed a decrease in soft tissues when compared with the control group. In addition, the activity level of some enzymes representing glycolytic enzymes as hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK), lactate dehydrogenase (LDH), and glucose phosphate isomerase (GPI) in snail's tissues were reduced in response to the treatment. It was concluded that the pollution of the aquatic environment by herbicide would adversely affect the metabolism of the L. natalensis snails. Snails treated with Agave attenuate, Ammi visnaga, and Canna iridiflora plant had less toxic effect compared to snails treated with Paraquat. PMID:24081640

  1. Taken to the limit--Is desiccation stress causing precocious encystment of trematode parasites in snails?

    PubMed

    O'Dwyer, Katie; Poulin, Robert

    2015-12-01

    When hosts experience environmental stress, the quantity and quality of resources they provide for parasites may be diminished, and host longevity may be decreased. Under stress, parasites may adopt alternative strategies to avoid fitness reductions. Trematode parasites typically have complex life cycles, involving asexual reproduction in a gastropod first intermediate host. A rare phenomenon, briefly mentioned in the literature, and termed 'precocious encystment' involves the next stage in the parasites' life cycle (metacercarial cyst) forming within the preceding stage (redia), while still inside the snail. In the trematode Parorchis sp. NZ using rocky shore snails exposed to long periods outside water, we hypothesised that this might be an adaptive strategy against desiccation, preventing parasite emergence from the snail. To test this, we first investigated the effect of prolonged desiccation on the survival of two species of high intertidal snails. Secondly, we measured the reproductive output (cercarial production) of the parasite under wet and dry conditions. Finally, we quantified the influence of desiccation stress on the occurrence of precocious encystment. Snail mortality was higher under dry conditions, indicating stress, and it was somewhat exacerbated for infected snails. Parasite reproductive output differed between wet and dry conditions, with parasites of snails kept in dry conditions producing more cercariae when placed in water. Little variation was observed in the occurrence of precocious encystment, although some subtle patterns emerged. Given the stresses associated with living in high intertidal environments, we discuss precocious encystment as a possible stress response in this trematode parasite. PMID:26344863

  2. The susceptibility of Lymnaeid snails to Paramphistomum cervi infections in Mexico.

    PubMed

    Castro-Trejo, L; García-Vasquez, Z; Casildo-Nieto, J

    1990-02-01

    The occurrence of Paramphistomum cervi has been reported in Mexico, but its intermediate hosts have not been identified. Five species of snails of the genus Lymnaea, L. bulimoides, L. columella, L. cubensis, L. humilis and L. palustris, were collected in Mexico. Only three of the exposed species, L. palustris, L. cubensis and L. humilis, became infected with P. cervi. The first of these snail species was highly susceptible to infection and a higher number of the exposed snails shed cercariae. It is suggested that L, palustris may act as an important vector of P. cervi in Mexico. PMID:2343525

  3. Changing Arctic Ocean freshwater pathways.

    PubMed

    Morison, James; Kwok, Ron; Peralta-Ferriz, Cecilia; Alkire, Matt; Rigor, Ignatius; Andersen, Roger; Steele, Mike

    2012-01-01

    Freshening in the Canada basin of the Arctic Ocean began in the 1990s and continued to at least the end of 2008. By then, the Arctic Ocean might have gained four times as much fresh water as comprised the Great Salinity Anomaly of the 1970s, raising the spectre of slowing global ocean circulation. Freshening has been attributed to increased sea ice melting and contributions from runoff, but a leading explanation has been a strengthening of the Beaufort High--a characteristic peak in sea level atmospheric pressure--which tends to accelerate an anticyclonic (clockwise) wind pattern causing convergence of fresh surface water. Limited observations have made this explanation difficult to verify, and observations of increasing freshwater content under a weakened Beaufort High suggest that other factors must be affecting freshwater content. Here we use observations to show that during a time of record reductions in ice extent from 2005 to 2008, the dominant freshwater content changes were an increase in the Canada basin balanced by a decrease in the Eurasian basin. Observations are drawn from satellite data (sea surface height and ocean-bottom pressure) and in situ data. The freshwater changes were due to a cyclonic (anticlockwise) shift in the ocean pathway of Eurasian runoff forced by strengthening of the west-to-east Northern Hemisphere atmospheric circulation characterized by an increased Arctic Oscillation index. Our results confirm that runoff is an important influence on the Arctic Ocean and establish that the spatial and temporal manifestations of the runoff pathways are modulated by the Arctic Oscillation, rather than the strength of the wind-driven Beaufort Gyre circulation. PMID:22222749

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

    PubMed Central

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

    1964-01-01

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

  5. The recent apple snails of Africa and Asia (Mollusca: Gastropoda: Ampullariidae: Afropomus, Forbesopomus, Lanistes, Pila, Saulea): a nomenclatural and type catalogue. The apple snails of the Americas: addenda and corrigenda.

    PubMed

    Cowie, Robert H

    2015-01-01

    Ampullariidae are freshwater snails predominantly distributed in humid tropical and sub-tropical habitats in Africa, South and Central America and Asia. This catalogue is concerned only with the non-fossil Old World species, the majority of which are placed in the genera Pila and Lanistes, with a few species in Afropomus, Forbesopomus and Saulea. Pila occurs in Africa and Asia, Lanistes, Afropomus and Saulea only in Africa and Forbesopomus only in Asia. New World taxa were catalogued in a previous publication. The taxonomy of the group is heavily based on shell morphology but the true number of valid taxa remains unknown, pending revisionary work. This catalogue provides the rigorous nomenclatural base for this future work by bringing together all the available and unavailable genus-group and species-group names that have been applied to Recent Asian and African ampullariids, indicating their current nomenclatural status (species, subspecies, synonyms, etc.). Fossil taxa are not included. The catalogue lists 21 published genus-group and 244 published species-group names of Old World ampullariids, excluding 25 names that are incertae sedis and cannot be definitively determined as Old or New World. Of these 265 Old World names, five genus-group and 104 species-group (including 30 infraspecific) names are currently valid. There are 16 genus-group synonyms, 118 species-group synonyms and four species-group homonyms that are not treated as junior synonyms. Also listed are five unavailable family-group, one unavailable genus-group and 18 unavailable species-group names, and a number of unpublished names from museum labels. The catalogue provides bibliographic details for all published names, locations of type material, details of type localities and geographic distributions as far as can be ascertained given the confused state of the taxonomy. The catalogue is a work of nomenclature; it is not a revisionary work of taxonomy. Additional details and corrections to the earlier catalogue of the apple snails of the Americas are provided. No new names are proposed. Seven apparently new combinations are introduced, all with the genus Pila Preston: complicata Reeve, dira Reeve, major Germain (described as a variety of ovata Olivier), major Germain (described as a variety of speciosa Philippi), obvia Mabille, pallens Philippi, turbinoides Reeve. PMID:25947491

  6. Growth rate of the intermediate snail host Galba truncatula influences redial development of the trematode Fascioloides magna.

    PubMed

    Rondelaud, D; Novobilský, A; Höglund, J; Kašný, M; Pankrác, J; Vignoles, P; Dreyfuss, G

    2014-12-01

    A total of 850 pre-adult Galba truncatula (shell height, 4 mm), originating from four French snail populations differing in shell height at the adult stage (from 6.5 to 12 mm), were individually subjected at 20°C to single-miracidium infections with Fascioloides magna. At day 75 post-exposure, the surviving snails were dissected, and rediae and cercariae were counted. Snail groups differed in shell growth during the experiment: from 1.8 ± 0.4 mm in group A up to 4.0 ± 1.1 mm in group D. The prevalence of F. magna infection, the numbers of free rediae and cercariae significantly increased together with increasing growth of infected snails during the experiment. Group A produced 1-6 first-generation rediae per snail and the mean daughter redia production ranged from 7.5 second-generation rediae (when a single first generation per snail developed) to 2.3 (6 first-generation rediae per snail). In contrast, up to ten first-generation rediae were noted in group D, and each mother redia gave daughter rediae with averages ranging from 1.5 (ten first-generation rediae per snail) to 13 (a single first generation per snail). In conclusion, the development of F. magna in G. truncatula exhibited both inter- and intrapopulation variability, where the development of rediae and cercariae was positively correlated with snail growth. PMID:23710885

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

    PubMed Central

    Deheyn, Dimitri D.; Wilson, Nerida G.

    2011-01-01

    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

  8. 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

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

    PubMed

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

    2011-08-01

    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

  10. Gastropod-borne helminths: a look at the snail-parasite interplay

    E-print Network

    Giannelli, Alessio; Cantacessi, Cinzia; Colella, Vito; Dantas-Torres, Filipe; Otranto, Domenico

    2015-12-28

    More than 300 million people suffer from a range of diseases caused by snail-borne helminths, predominantly flatworms and roundworms, whose life cycles are characterised by a diversified ecology and epidemiology. Despite the plethora of data...

  11. Endemic Land Snail Fauna (Mollusca) on a Remote Peninsula in the Ogasawara Archipelago, Northwestern Pacific1

    E-print Network

    Davison, Angus

    ) and destruction of native forest, as well as predation by intro- duced species (e.g., flatworms, the predatory, continuing grazing by goats and predation by rats and flatworms may soon lead to extinction of the snail

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

    PubMed Central

    2012-01-01

    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

  13. Solar radio-transmitters on snail kites in Florida

    USGS Publications Warehouse

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

    1989-01-01

    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.

  14. The effects of wetland habitat structure on Florida apple snail density

    USGS Publications Warehouse

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

    2006-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Verbitskaya, Olga; Manukovsky, Nickolay; Kovalev, Vladimir

    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.

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

    SciTech Connect

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

    1994-01-01

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

  17. Bacterial diversity in different regions of gastrointestinal tract of Giant African snail (Achatina fulica).

    PubMed

    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

    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

  18. Small mammals cause non-trophic effects on habitat and associated snails in a native system.

    PubMed

    Huntzinger, Mikaela; Karban, Richard; Maron, John L

    2011-12-01

    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

  19. Snail Nuclear Transport: the Gateways Regulating Epithelial-to-Mesenchymal Transition?

    PubMed Central

    Muqbil, Irfana; Wu, Jack; Aboukameel, Amro; Mohammad, Ramzi M.; Azmi, Asfar S.

    2014-01-01

    Epithelial-to-mesenchymal transition (EMT) and the reverse process (MET) plays central role in organ developmental biology. It is a fine tuned process that when disturbed leads to pathological conditions especially cancers with aggressive and metastatic behavior. Snail is an oncogene that has been well established to be a promoter of EMT through direct repression of epithelial morphology promoter E-cadherin. It can function in the nucleus, in the cytosol and as discovered recently, extracellularly through secretory vesicular structures. The intracellular transport of snail has for long been shown to be regulated by the nuclear pore complex. One of the Karyopherins, importin alpha, mediates snail import, while importin beta/exportin 1 (Xpo1) or chromosome maintenance region 1 (CRM1) is its major nuclear exporter. A number of additional biological regulators are emerging that directly modulate Snail stability by altering its subcellular localization. These observations indicate that targeting the nuclear transport machinery could be an important and as of yet, unexplored avenue for therapeutic intervention against the EMT processes in cancer. In parallel, a number of novel agents that disrupt nuclear transport have recently been discovered and are being explored for their anti-cancer effects in the early clinical settings. Through this review we provide insights on the mechanisms regulating snail subcellular localization and how this impacts EMT. We discuss strategies on how the nuclear transport function can be harnessed to rein in EMT through modulation of snail signaling. PMID:24954011

  20. Glyphosate herbicide induces genotoxic effect and physiological disturbances in Bulinus truncatus snails.

    PubMed

    Bakry, Fayez A; Ismail, Somaya M; Abd El-Atti, Mahmoud S

    2015-09-01

    Herbicides are being used in agriculture for controlling noxious weed. Glyphosate is a herbicide that is widely applied to cereal crops in Egypt and is used in controlling a very broad spectrum of weeds. The present study was designed to investigate the response of the snail Bulinus truncatus as a bioindicator for physiological and molecular aspects of B.?truncatus snails after exposure to sublethal concentrations of glyphosate for two weeks. In treating snails, glucose concentration (GL) in the haemolymph as well as lactate (LT) in soft tissues of treated snails increased, while glycogen (GN), pyruvate (PV), total protein (TP), nucleic acids (DNA and RNA) levels in snail's tissues decreased. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR), thioredoxin reductase (TrxR), glycogen phosphorylase (GP), glucose-6-phosphatase (G-6-Pase), succinic dehydrogenase (SDH) and lactic dehydrogenase (LDH) enzymes in homogenate of snail's tissues were reduced in response to the treatment with the herbicide, while lipid peroxide (LP), sorbitol dehydrogenase (SDH) and transaminases (GOT and GPT) activity increased (P?

  1. Doxorubicin enhances Snail/LSD1-mediated PTEN suppression in a PARP1-dependent manner

    PubMed Central

    Lin, Yiwei; Kang, Tiebang; Zhou, Binhua P

    2014-01-01

    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

  2. Snail mediates medial-lateral patterning of the ascidian neural plate.

    PubMed

    Hudson, Clare; Sirour, Cathy; Yasuo, Hitoyoshi

    2015-07-15

    The ascidian neural plate exhibits a regular, grid-like arrangement of cells. Patterning of the neural plate across the medial-lateral axis is initiated by bilateral sources of Nodal signalling, such that Nodal signalling induces expression of lateral neural plate genes and represses expression of medial neural plate genes. One of the earliest lateral neural plate genes induced by Nodal signals encodes the transcription factor Snail. Here, we show that Snail is a critical downstream factor mediating this Nodal-dependent patterning. Using gain and loss of function approaches, we show that Snail is required to repress medial neural plate gene expression at neural plate stages and to maintain the lateral neural tube genetic programme at later stages. A comparison of these results to those obtained following Nodal gain and loss of function indicates that Snail mediates a subset of Nodal functions. Consistently, overexpression of Snail can partially rescue a Nodal inhibition phenotype. We conclude that Snail is an early component of the gene regulatory network, initiated by Nodal signals, that patterns the ascidian neural plate. PMID:25962578

  3. Role of Ras signaling in the induction of snail by transforming growth factor-beta.

    PubMed

    Horiguchi, Kana; Shirakihara, Takuya; Nakano, Ayako; Imamura, Takeshi; Miyazono, Kohei; Saitoh, Masao

    2009-01-01

    The epithelial-mesenchymal transition (EMT) is a crucial morphological event that occurs during the progression of epithelial tumors. EMT can be induced by transforming growth factor (TGF)-beta in some tumor cells. Here, we demonstrate the molecular mechanism whereby Snail, a key regulator of EMT, is induced by TGF-beta in tumor cells. Snail induction by TGF-beta was highly dependent on cooperation with active Ras signals, and silencing of Ras abolished Snail induction by TGF-beta in pancreatic cancer Panc-1 cells. Transfection of constitutively active Ras into HeLa cells led to induction of Snail by TGF-beta, while representative direct targets of TGF-beta, including Smad7 and PAI-1, were not affected by Ras signaling. Using mitogen-activated protein kinase inhibitors or Smad3 or Smad2 mutants, we found that phosphorylation at the linker region of Smad2/3 was not required for the induction of Snail by TGF-beta. Taken together, these findings indicate that Ras and TGF-beta-Smad signaling selectively cooperate in the induction of Snail, which occurs in a Smad-dependent manner, but independently of phosphorylation at the linker region of R-Smads by Ras signaling. PMID:19010789

  4. Foraging and refuge use by a pond snail: Effects of physiological state, predators, and resources

    NASA Astrophysics Data System (ADS)

    Wojdak, Jeremy M.

    2009-09-01

    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.

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

    PubMed Central

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

    2013-01-01

    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

  6. Second intermediate host land snails and definitive host animals of Brachylaima cribbi in southern Australia.

    PubMed

    Butcher, A R; Grove, D I

    2005-03-01

    This study of infection of southern Australian land snails with Brachylaima cribbi metacercariae has shown that all commonly encountered native and introduced snails are susceptible second intermediate hosts. The range of infected snails is extensive with metacercariae-infected snails being present in all districts across southern Australia. C. virgata has the highest average natural metacercarial infection intensity of 6.1 metacercariae per infected snail. The susceptibility of birds, mammals and reptiles to B. cribbi infection was studied in South Australia by capturing, dissecting and examining the intestinal tract contents of animals which commonly eat land snails as a food source. Indigenous Australian little ravens (Corvus mellori), which are a common scavenger bird, and two other passeriform birds, the black bird (Turdus merula) and the starling (Sturnus vulgaris), which are both introduced European birds, were found to have the highest infection rates of all animals examined. Other birds found infected with B. cribbi were an emu (Dromaius novaehollandiae), chickens (Gallus gallus) and a pigeon (Columba livia). Natural infections were also detected in field mice (Mus domesticus) and shingleback lizards (Tiliqua rugosa) although the intensity of infection was lower than that observed in birds. Susceptibility studies of laboratory mice, rats and ducks showed that mice developed patent infections which persisted for several weeks, rats developed a short-lived infection of three weeks' duration and ducks did not support infection. This study has shown for the first time that a brachylaimid can infect a wide host range of birds, mammals and reptiles in nature. PMID:15828579

  7. A repetitive DNA probe for the sensitive detection of Fasciola hepatica infected snails.

    PubMed

    Kaplan, R M; Dame, J B; Reddy, G R; Courtney, C H

    1995-05-01

    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

  8. How terrestrial snails can be used in risk assessment of soils.

    PubMed

    de Vaufleury, Annette; Coeurdassier, Michaël; Pandard, Pascal; Scheifler, Renaud; Lovy, Christiane; Crini, Nadia; Badot, Pierre-Marie

    2006-03-01

    Among soil invertebrates, terrestrial snails are herbivorous and detritivorous organisms exposed to polluted soils by both digestive and cutaneous routes. Using laboratory-reared snails (Helix aspersa aspersa), we describe how the effects of contaminants on survival and growth of snails can be evaluated in laboratory bioassays. A national ring test was performed to assess the effect of Cd added to the soil or to the food. The ecotoxicity of sewage sludge also was evaluated. The present results demonstrate that toxicity depends on both the pollutants and the exposure route. Cadmium was sixfold more toxic for snails exposed via food contamination (median effective concentration [EC50], 68-139 microg/g) than via soil contamination (EC50, 534-877 microg/g), whereas the opposite occurred with the sewage sludge (EC50, 55% of sludge in the food and 10% of waste in the soil). A logistic relationship linked growth inhibition and internal Cd concentrations, which can reach 2,000 microg/g in the viscera of snails exposed to 626 microg/g in the food. No clear trend was found between Cu, Zn, Pb, Cr, and Ni concentrations in the sludge and in snail tissues. These data enabled the development of an international standard, which should enhance the use of terrestrial gastropods for both fundamental research and routine risk assessment in the terrestrial environment. PMID:16566165

  9. Doxorubicin enhances Snail/LSD1-mediated PTEN suppression in a PARP1-dependent manner.

    PubMed

    Lin, Yiwei; Kang, Tiebang; Zhou, Binhua P

    2014-01-01

    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

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

    PubMed Central

    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.

    2015-01-01

    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

  11. Endothelial Snail Regulates Capillary Branching Morphogenesis via Vascular Endothelial Growth Factor Receptor 3 Expression

    PubMed Central

    Park, Jeong Ae; Kim, Dong Young; Kim, Young-Myeong; Kwon, Young-Guen

    2015-01-01

    Vascular branching morphogenesis is activated and maintained by several signaling pathways. Among them, vascular endothelial growth factor receptor 2 (VEGFR2) signaling is largely presented in arteries, and VEGFR3 signaling is in veins and capillaries. Recent reports have documented that Snail, a well-known epithelial-to-mesenchymal transition protein, is expressed in endothelial cells, where it regulates sprouting angiogenesis and embryonic vascular development. Here, we identified Snail as a regulator of VEGFR3 expression during capillary branching morphogenesis. Snail was dramatically upregulated in sprouting vessels in the developing retinal vasculature, including the leading-edged vessels and vertical sprouting vessels for capillary extension toward the deep retina. Results from in vitro functional studies demonstrate that Snail expression colocalized with VEGFR3 and upregulated VEGFR3 mRNA by directly binding to the VEGFR3 promoter via cooperating with early growth response protein-1. Snail knockdown in postnatal mice attenuated the formation of the deep capillary plexus, not only by impairing vertical sprouting vessels but also by downregulating VEGFR3 expression. Collectively, these data suggest that the Snail-VEGFR3 axis controls capillary extension, especially in vessels expressing VEGFR2 at low levels. PMID:26147525

  12. Endothelial Snail Regulates Capillary Branching Morphogenesis via Vascular Endothelial Growth Factor Receptor 3 Expression.

    PubMed

    Park, Jeong Ae; Kim, Dong Young; Kim, Young-Myeong; Lee, In-Kyu; Kwon, Young-Guen

    2015-07-01

    Vascular branching morphogenesis is activated and maintained by several signaling pathways. Among them, vascular endothelial growth factor receptor 2 (VEGFR2) signaling is largely presented in arteries, and VEGFR3 signaling is in veins and capillaries. Recent reports have documented that Snail, a well-known epithelial-to-mesenchymal transition protein, is expressed in endothelial cells, where it regulates sprouting angiogenesis and embryonic vascular development. Here, we identified Snail as a regulator of VEGFR3 expression during capillary branching morphogenesis. Snail was dramatically upregulated in sprouting vessels in the developing retinal vasculature, including the leading-edged vessels and vertical sprouting vessels for capillary extension toward the deep retina. Results from in vitro functional studies demonstrate that Snail expression colocalized with VEGFR3 and upregulated VEGFR3 mRNA by directly binding to the VEGFR3 promoter via cooperating with early growth response protein-1. Snail knockdown in postnatal mice attenuated the formation of the deep capillary plexus, not only by impairing vertical sprouting vessels but also by downregulating VEGFR3 expression. Collectively, these data suggest that the Snail-VEGFR3 axis controls capillary extension, especially in vessels expressing VEGFR2 at low levels. PMID:26147525

  13. [Effects of heavy metals on snail development. Use of snails as bio-indicators of heavy metal pollution for the preservation of human health].

    PubMed

    Gomot, A

    1997-01-01

    The use of snails as biological indicators is particularly appropriate for metals, which they accumulate in their organs. The aim of the present experiment was to carry out a rigorous experimentation in the laboratory and in the wild in order to develop a methodology for the use of snails at a known stage of growth that would give precise information on the toxicity of heavy metals for different concentrations and durations of exposure. We have developed a test of toxicity based on the effects of a noxious and carcinogenic element, cadmium, on the land-snail Helix aspersa aspersa (H.a.a) of one month of age. Five concentrations (50 to 800 micrograms/g), were selected to estimate the concentrations causing 50% inhibition of growth (EC 50) at 14 days: 190 micrograms/g and at 28 days: 180 micrograms/g. A soil matrix contaminated with metals (soil including 800 micrograms/g Cr, 20 micrograms/g Cd, 800 micrograms/g Pb and 2000 micrograms/g Zn) was incorporated into the food at 50 and 75%, it too inhibited the growth of juvenile snails compared to incorporation of control soil. An accurate and rapid (2 to 4 weeks) method is therefore available for the evaluation of the toxicity of pollutants by ingestion. The first trials of this method in the wild consisted of placing batches of 2-month-old snails, identical to those used in the first lab tests, in locations that were either polluted or not. Differences in growth were observed depending on the locations; analysis of the levels of metal in the organs of the snails should enable us to check if there is a correlation between these levels and the growth rates. The results obtained with cadmium compared to those of other authors working with earthworms and soil arthropods show that snails give responses to concentrations comparable to those of earthworms and much more rapidly and with more sensitivity than those of collembolla for example. The ease of handling snails and the perfect control of their breeding are essential factors in carrying out reliable bioassays in toxicology and in ecotoxicology. PMID:9162514

  14. [Cultivation technics for freshwater fish].

    PubMed

    Rosenthal, H

    1990-07-01

    A general overview is presented on the various cultivation techniques in modern freshwater aquaculture. Included are overall production figures for finfish production in the most important producing countries of Europe. Major emphasis is placed on the situation of aquaculture development in the Federal Republic of Germany, providing details on the structure of the industry in the states of Bavaria, Lower Saxony, and Schleswig-Holstein. The trend towards intensification and its implications to system performance is described. The development of recirculation systems, particular for eel farming, is outlined, indicating the various problems related to system design, local conditions and species requirements. Future trends and research needs are identified. PMID:2205459

  15. Davis Pond Freshwater Prediversion Biomonitoring Study: Freshwater Fisheries and Eagles

    USGS Publications Warehouse

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

    2008-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  17. Food composition and feeding habits of some fresh water fishes in various water systems at Abbassa, Egypt, with special reference to snails transmitting diseases.

    PubMed

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

    2005-08-01

    Study of feeding habits of freshwater fishes collected from ponds at World Fish Center (ICLARM) showed that the African catfish, Clarias gariepinus and Forskal catfish, Bagras bayad had the highest proportion of full stomachs (31-58% & 44-45% respectively). In cichlid fishes, the rate of full stomachs was much lower, being 0.0-12.5% and showed higher incidence of empty stomachs that varied from 37.5% for Oreochromis niloticus to 78.3% for Sarotherodon galilaeus. Food items were analyzed by the percentage of point assessment (P%), abundance (N%) and frequency of occurrence (F%). Results of the three methods of analyses (Index of relative importance, I.R.I) emphasized the importance of plants (1214.7) as a major food resource in the stomach of Nile tilapia, O. niloticus followed by shell fragments (628.5), whereas, snail soft bodies were the main food category in the diet of hybrid tilapia O. niloticus x O. aureus (2539.3). Shell fragments (652) and snail soft bodies (296.9) were the 1st in relative importance as foods of O. aurea. In case of S. galillae, shell fragments (338) came 2nd in I.R.I. after plants (559). Present investigation shows that shell fragments were represented by 11.1% and 15.1% in the diet of African catfish, C. gariepinus by (N%) and (P%) methods, however, they came as the second food item in its diet by I.R.I (1237.3). According to F% method, both shell fragments and Crustacea were present in the diet of C. gariepinus considerable proportions each of 47.4%. Shell fragments were represented by low proportions in the diet of B. bayad 3.9, 2.1 and 22.2 by N%, P% and F% respectively. PMID:16083073

  18. Freshwater Biological Traits Database (Final Report)

    EPA Science Inventory

    Cover of the <span class=Freshwater Biological Traits Database Final Report"> This final report discusses the development of a database of freshwater biolo...

  19. Effects of Pollution on Freshwater Fish.

    ERIC Educational Resources Information Center

    Brungs, W. A.; And Others

    1978-01-01

    Presents a literature review of the effects of pollution on freshwater fish, covering publications of 1976-77. This review includes: (1) water quality; (2) pesticide pollutants; (3) chemical pollutants; (4) miscellaneous pollutants; and (5) physical factors of pollution on freshwater fish. A list of 338 references is also presented. (HM)

  20. Reclaiming freshwater sustainability in the Cadillac Desert

    E-print Network

    Sinha, Tushar

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

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

    PubMed Central

    Yeung, Norine W; Hayes, Kenneth A

    2013-01-01

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

  2. FBXO11 promotes ubiquitination of the Snail family of transcription factors in cancer progression and epidermal development.

    PubMed

    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

    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

  3. Effects of washing produce contaminated with the snail and slug hosts of Angiostrongylus cantonensis with three common household solutions.

    PubMed

    Yeung, Norine W; Hayes, Kenneth A; Cowie, Robert H

    2013-06-01

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

  4. Changes in epilithic communities due to individual and combined treatments of zinc and snail grazing in stream mesocosms

    SciTech Connect

    Genter, R.B.; Colwell, F.S.; Pratt, J.R.; Cherry, D.S.; Cairns, J. Jr.

    1988-06-01

    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.

  5. Inhibition of Snail1-DNA-PKcs Protein-Protein Interface Sensitizes Cancer Cells and Inhibits Tumor Metastasis*

    PubMed Central

    Kang, Ga-Young; Pyun, Bo-Jeong; Seo, Haeng Ran; Jin, Yeung Bae; Lee, Hae-June; Lee, Yoon-Jin; Lee, Yun-Sil

    2013-01-01

    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

  6. Influence of copper on the feeding rate, growth and reproduction of the golden apple snail, Pomacea canaliculata Lamarck.

    PubMed

    Peña, Silvia C; Pocsidio, Glorina N

    2007-12-01

    The influence of copper on feeding rate, growth, and reproduction of Pomacea canaliculata Lamarck was evaluated. Ten days of exposure to copper of relatively high concentration (67.5 microg/L) reduced the snails' feeding rate and retarded their growth. Exposure to 20 microg/L after 36 days increased feeding rate to 28%. After 20 days of exposure at 30 microg/L, snail's growth was significant but thereafter declined. Growth of all snails including control was negligible by day 50 when snails were in the reproductive state. Copper did not affect reproduction. PMID:17999015

  7. SNAIL transcription factor increases the motility and invasive capacity of prostate cancer cells

    PubMed Central

    OSORIO, LUIS A.; FARFÁN, NANCY M.; CASTELLÓN, ENRIQUE A.; CONTRERAS, HÉCTOR R.

    2016-01-01

    The incidence and mortality rates of prostate cancer (PCa) are increasing, and PCa is almost the second-leading cause of cancer-associated mortality in men. During tumor progression, epithelial cells decrease the number of adhesion molecules, change their polarity and position, rearrange their cytoskeleton and increase their migratory and invasive capacities. These changes are known under the concept of epithelial-mesenchymal transition (EMT). EMT is characterized by an upregulation of certain transcription factors, including SNAIL1, which represses genes that are characteristic of an epithelial phenotype, including E-cadherin, and indirectly increase the expression levels of genes, which are associated with the mesenchymal phenotype. It has been suggested that the transcription factor, SNAIL1, decreases the proliferation and increases the migratory and invasive capacities of PCa cell lines. The present study was performed using LNCaP and PC3 cell lines, in which the expression levels of SNAIL1 were increased or silenced through the use of lentiviral vectors. The expression levels of EMT markers were quantified using reverse transcription-quantitative polymerase chain reaction and western blot analysis. In addition, cell survival was analyzed using an MTS assay; cell proliferation was examined using an antibody targeting Ki-67; migration on plates with 8 µm pores to allow the passage of cells; and invasiveness was analyzed using a membrane chamber covered in dried basement membrane matrix solution. The levels of apoptosis were determined using a Caspase 3/7 assay containing a substrate modified by caspases 3 and 7. The results demonstrated that the overexpression and silencing of SNAIL1 decreased cell proliferation and survival. However, the overexpression of SNAIL1 decreased apoptosis, compared with cells with the SNAIL1-silenced cells, in which cell apoptosis increased. The migration and invasive capacities increased in the cells overexpressing SNAIL1, and decreased when SNAIL1 was silenced. In conclusion, PCa cells overexpressing SNAIL1 exhibited characteristics of an EMT phenotype, whereas the silencing of the SNAIL1 transcriptional repressor promoted an epithelial-like phenotype, with decreased migration and invasion, characteristic of mesenchymal cells. PMID:26648419

  8. Release of Lungworm Larvae from Snails in the Environment: Potential for Alternative Transmission Pathways

    PubMed Central

    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

    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

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

    PubMed

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

    2009-03-01

    A survey of digenean zoonotic trematodes infecting snails and fishes in a North Vietnamese freshwater fish culture system revealed shedding of three types of parapleurolophocercous cercariae from the snail host Melanoides tuberculata and the presence of metacercariae within the genus Haplorchis (H. pumilio and H. taichui) and Procerovum sp. in tissues of cultured fishes (silver carp, Indian carp and climbing perch). No morphological characters were able to link the different cercariae specifically to any of the metacercariae. Subsequent molecular work including PCR and sequencing of ribosomal DNA (the ITS2 region) in cercariae and metacercariae associated only one type of the cercariae to the recovered H. pumilio metacercariae. Further, full identity (100%) was found with regard to the ITS sequence of adult H. pumilio obtained from the same North Vietnamese region. None of the cercariae showed sequence identities with H. taichui but more than 99% identity was found between one cercaria type and the Procerovum sp. metacercaria. It was indicated that trematode parasites of farmed fishes may originate from sources outside the fish ponds and may be introduced as free-swimming cercariae when pond water is being replenished by river water. Likewise, cercariae from the ponds may not always result in metacercarial infections of the farmed fishes. The present study frames the needs for including molecular techniques as auxiliary tools when conducting ecological studies of cercariae in complex ecosystems. The parasites recorded in the fish ponds are not only known to affect the health of aquacultured fishes but also the documented zoonotic potential of the diagnosed metacercaria calls for alerts regarding human consumption of raw or inadequately processed fish dishes. PMID:19056180

  10. The Snail repressor is required for PMC ingression in the sea urchin embryo

    PubMed Central

    Wu, Shu-Yu; McClay, David R.

    2011-01-01

    In metazoans, the epithelial-mesenchymal transition (EMT) is a crucial process for placing the mesoderm beneath the ectoderm. Primary mesenchyme cells (PMCs) at the vegetal pole of the sea urchin embryo ingress into the floor of the blastocoele from the blastula epithelium and later become the skeletogenic mesenchyme. This ingression movement is a classic EMT during which the PMCs penetrate the basal lamina, lose adherens junctions and migrate into the blastocoele. Later, secondary mesenchyme cells (SMCs) also enter the blastocoele via an EMT, but they accompany the invagination of the archenteron initially, in much the same way vertebrate mesenchyme enters the embryo along with endoderm. Here we identify a sea urchin ortholog of the Snail transcription factor, and focus on its roles regulating EMT during PMC ingression. Functional knockdown analyses of Snail in whole embryos and chimeras demonstrate that Snail is required in micromeres for PMC ingression. Snail represses the transcription of cadherin, a repression that appears evolutionarily conserved throughout the animal kingdom. Furthermore, Snail expression is required for endocytosis of cadherin, a cellular activity that accompanies PMC ingression. Perturbation studies position Snail in the sea urchin micromere-PMC gene regulatory network (GRN), downstream of Pmar1 and Alx1, and upstream of several PMC-expressed proteins. Taken together, our findings indicate that Snail plays an essential role in PMCs to control the EMT process, in part through its repression of cadherin expression during PMC ingression, and in part through its role in the endocytosis that helps convert an epithelial cell to a mesenchyme cell. PMID:17287249

  11. Detection and Genetic Analysis of Noroviruses and Sapoviruses in Sea Snail.

    PubMed

    Ozawa, Hiroki; Kumazaki, Makoto; Ueki, Satoshi; Morita, Masahiro; Usuku, Shuzo

    2015-12-01

    An outbreak of acute gastroenteritis occurred at a restaurant in Yokohama in December 2011. Because many of the customers had consumed raw sea snail, sea snail was suspected to be the source of this outbreak. To determine whether sea snail contains Norovirus (NoV) or Sapovirus (SaV), we analyzed 27 sea snail samples collected over 5 months (May, June, August, October, and December 2012) and 59.3 % were positive for NoV and/or SaV. The levels of NoV ranged from 1.5 × 10(3) to 1.5 × 10(5) copies/g tissue, and those of SaV from 1.5 × 10(2) to 1.3 × 10(3) copies/g tissue. The highest levels were observed in sea snails collected in December. A phylogenetic analysis of the NoVs showed that the viral strains were NoV genotypes GI.4, GI.6, GII.4, GII.12, GII.13, and GII.14, and the SaV strains were genotypes GI.2 and GI.3. The NoV GII.4 Sydney 2012 variants were only detected in December. This variant was a major source of gastroenteritis in Japan in the winter of 2012/2013. In contrast, the NoV GII.4 strains detected in May and June 2012 were not the Sydney 2012 variant. This study demonstrates that sea snail contains multiple genogroups and genotypes of NoV and SaV strains. We conclude that the sea snail presents a risk of gastroenteritis when consumed raw. PMID:26100718

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

    NASA Astrophysics Data System (ADS)

    Yagyu, Yoshihito; Tsuji, Satoshi; Satoh, Saburoh; Yamabe, Chobei

    The apple snail, Pomacea canaliculata, brought to Japan from Taiwan for human consumption in the 1980s, has come to be considered as deleterious for rice cultivation. The snail is unable to injure young rice plants while receiving electric shock because the snail retracts its entire body into its shell and shuts its aperture with its operculum. Electric shock should be applied intermittently to reduce the amount of energy that is wasted when the snail is in its shell made of one of the insulator. The minimum electric shock required for controlling snails and the time required for movement after application of electric shock to determine the frequency of each electric shock were investigated using two methods; vertical and horizontal application of the electrical stimulation. The results showed that there is a strong correlation between the strength of electric shock and the reaction of the snails, and electric shock made snails inactive when it was applied 0.35 A/m2 in the horizontal direction and 0.45 A/m2 in the vertical direction with water of 11 mS/m. A positive correlation was also found between electric shock and the reaction of the snails and shell height. In comparison with larger snails, the smaller snails had higher threshold levels against electric current density because their shorter feet tended to have lower voltage dorp. Moreover, the frequency of electric shock should be chosen the minimum duration for the inactive condition, and it was approximately 10 seconds. Consequently the direction of electric current should be in the horizontal direction above 0.35 A/m2 and the frequency of electric shock should be less than 10 seconds for practical use. However, electric shock would have to be maintained at greater than 0.35 A/m2 because snails might become habituated to electric shock and water in paddy field would have high electric conductivity.

  13. Prostaglandin E2 accelerates invasion by upregulating Snail in hepatocellular carcinoma cells.

    PubMed

    Zhang, Min; Zhang, Hai; Cheng, Shanyu; Zhang, Dengcai; Xu, Yan; Bai, Xiaoming; Xia, Shukai; Zhang, Li; Ma, Juan; Du, Mingzhan; Wang, Yipin; Wang, Jie; Chen, Meng; Leng, Jing

    2014-07-01

    Our previous studies showed that prostaglandin E2 (PGE2) promotes hepatoma cell growth and migration, as well as invasion; however, the precise mechanism remains elusive. Snail and p65 protein levels were detected in human samples with hepatocellular carcinoma (HCC) by immunohistochemistry (IHC) staining. HCC cell lines (Huh-7 and Hep3B) were used for in vitro experiments. PGE2/Akt/NF-?B pathway was investigated in Huh-7 and Hep3B cells after treatment with PGE2, EP4 receptor (EP4R) agonist, Akt inhibitor, and NF-?B inhibitor, respectively, by real-time reverse transcription (RT)-PCR, Western blotting, and immunofluorescence (IF) staining. In vitro cell invasion assay was performed to evaluate the effect of PGE2 on tumor invasiveness. Knockdown of EP4R was carried out in Huh-7 cells through plasmid-based small interfering RNA (siRNA) approach to confirm the regulation of PGE2 on Snail by EP4R. Dual luciferase reporter assay was performed to assess Snail promoter activity in Huh-7 cell after treatment with EP4R agonist. We found that the protein levels of Snail were higher in HCC tissues than those in control and that PGE2 and EP4R agonist treatment significantly increased Snail expression in Huh-7 and Hep3B cells. EP4R agonist also profoundly promoted invasiveness of Huh-7 cells. Knockdown of the EP4R by siRNA completely blocked the PGE2-induced upregulation of Snail expression and reduced invasiveness of Huh-7 cells. We failed to find that EP4R-induced upregulation of Snail was reversed by inhibition of cAMP response element-binding protein (CREB), a canonical downstream target of EP4R. Alternatively, EP4R agonist treatment significantly increased the levels of phosphorylated EGFR and Akt both in Huh-7 and Hep3B cells. AG1478, an EGFR inhibitor, blocked the phosphorylation of Akt. The levels of phosphorylated I?B increased in Huh-7 cells after treatment with EP4R agonist for 30 min. The levels of phosphorylated p65 started to increase in Huh-7 cells treated with EP4R agonist for 4 h, and p65 translocated into the nucleus. In EP4R-agonist-treated Hep3B, the levels of phosphorylated p65 were also increased compared to the control group. The phosphorylation levels of p65 were significantly decreased in Huh-7 and Hep3B cells after treatment with the Akt signaling inhibitor LY294002 and EP4R agonist for 24 h. Treatment with the NF-?B inhibitor pyrrolidine dithiocarbamate (PDTC) at 10 ?M for 24 h blocked EP4R-agonist-induced Snail upregulation in Huh-7 and Hep3B cells. Furthermore, we obtained human Snail promoter sequence from TRED-Promoter Database and identified a putative binding site of NF-?B in the sequence through TFSEARCH analysis. Subsequently, we treated Huh-7 cells with EP4R agonist or EP4R agonist and PDTC (NF-?B antagonist) and found significantly increased Snail promoter activity after EP4R agonist treatment for 12 h. The increased Snail promoter activity could be partially abolished by additional PDTC treatment. In addition, p65 protein levels were found increased together with Snail in HCC tissues compared to normal liver tissues. In conclusion, PGE2 activates Akt/NF-?B signaling and then upregulates Snail via the EP4R/EGFR to promote migration and invasion in hepatoma cells. These findings may help future evaluation of novel chemo-preventive strategies for HCC. PMID:24760275

  14. Pathogenic agents in freshwater resources

    NASA Astrophysics Data System (ADS)

    Geldreich, Edwin E.

    1996-02-01

    Numerous pathogenic agents have been found in freshwaters used as sources for water supplies, recreational bathing and irrigation. These agents include bacterial pathogens, enteric viruses, several protozoans and parasitic worms more common to tropical waters. Although infected humans are a major source of pathogens, farm animals (cattle, sheep, pigs), animal pets (dogs, cats) and wildlife serve as significant reservoirs and should not be ignored. The range of infected individuals within a given warm-blooded animal group (humans included) may range from 1 to 25%. Survival times for pathogens in the water environment may range from a few days to as much as a year (Ascaris, Taenia eggs), with infective dose levels varying from one viable cell for several primary pathogenic agents to many thousands of cells for a given opportunistic pathogen.As pathogen detection in water is complex and not readily incorporated into routine monitoring, a surrogate is necessary. In general, indicators of faecal contamination provide a positive correlation with intestinal pathogen occurrences only when appropriate sample volumes are examined by sensitive methodology.Pathways by which pathogens reach susceptible water users include ingestion of contaminated water, body contact with polluted recreational waters and consumption of salad crops irrigated by polluted freshwaters. Major contributors to the spread of various water-borne pathogens are sewage, polluted surface waters and stormwater runoff. All of these contributions are intensified during periods of major floods. Several water-borne case histories are cited as examples of breakdowns in public health protection related to water supply, recreational waters and the consumption of contaminated salad crops. In the long term, water resource management must focus on pollution prevention from point sources of waste discharges and the spread of pathogens in watershed stormwater runoff.

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

    PubMed Central

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

    2014-01-01

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

  16. Heat shock proteins and survival strategies in congeneric land snails (Sphincterochila) from different habitats.

    PubMed

    Mizrahi, Tal; Heller, Joseph; Goldenberg, Shoshana; Arad, Zeev

    2012-09-01

    Polmunate land snails are subject to stress conditions in their terrestrial habitat, and depend on a range of behavioural, physiological and biochemical adaptations for coping with problems of maintaining water, ionic and thermal balance. The involvement of the heat shock protein (HSP) machinery in land snails was demonstrated following short-term experimental aestivation and heat stress, suggesting that land snails use HSPs as part of their survival strategy. As climatic variation was found to be associated with HSP expression, we tested whether adaptation of land snails to different habitats affects HSP expression in two closely related Sphincterochila snail species, a desert species Sphincterochila zonata and a Mediterranean-type species Sphincterochila cariosa. Our study suggests that Sphincterochila species use HSPs as part of their survival strategy following desiccation and heat stress, and as part of the natural annual cycle of activity and aestivation. Our studies also indicate that adaptation to different habitats results in the development of distinct strategies of HSP expression in response to stress, namely the reduced expression of HSPs in the desert-inhabiting species. We suggest that these different strategies reflect the difference in heat and aridity encountered in the natural habitats, and that the desert species S. zonata relies on mechanisms and adaptations other than HSP induction thus avoiding the fitness consequences of continuous HSP upregulation. PMID:22528052

  17. Prehistoric inter-archipelago trading of Polynesian tree snails leaves a conservation legacy.

    PubMed

    Lee, Taehwan; Burch, John B; Coote, Trevor; Fontaine, Benoît; Gargominy, Olivier; Pearce-Kelly, Paul; Foighil, Diarmaid O

    2007-11-22

    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

  18. Snail host finding by Fasciola hepatica and Trichobilharzia ocellata: compound analysis of "miracidia-attracting glycoproteins".

    PubMed

    Kalbe, M; Haberl, B; Haas, W

    2000-12-01

    The glycoconjugates from snail-conditioned water of Lymnaea truncatula and L. stagnalis which elicit typical host finding behavior in miracidia of Fasciola hepatica and Trichobilharzia ocellata were separated by anion-exchange chromatography and a two-step size-exclusion chromatography. We obtained fractions attractive for the parasites with MW of about 10(6) Da in both snail species. These fractions still contained species-specific information since miracidia responded only to molecules from their respective host snail. Analysis of the amino acid composition from the protein backbone revealed a similar composition in the effective fractions of both snails. Amounts of serine and threonine were higher than 30 mol %, which is typical for mucin-type glycoproteins. The carbohydrate moieties consisted mainly of galactose and fucose, but nine different other monosaccharides also were identified in smaller amounts. The heterogeneity of the molecules was also confirmed by the binding of six different lectins. Because of these characteristics, the effective molecules were termed "miracidia-attracting glycoproteins" (MAGs). MAGs may play an important role for parasite transmission, as they may increase the chance of an encounter between parasite and host and enable the miracidia to discriminate between their specific intermediate host and other unsuitable snail species. PMID:11162376

  19. The role of Snail1 transcription factor in colorectal cancer progression and metastasis

    PubMed Central

    Michalski, Marek; Wyrobiec, Grzegorz; Piecuch, Adam; Dittfeld, Anna; Harabin-S?owi?ska, Marzena; Boro?, Dariusz; Wojnicz, Romuald

    2015-01-01

    Snail1 is a zinc-finger transcription factor, which plays a role in colorectal cancer development by silencing E-cadherin expression and inducing epithelialmesenchymal transition (EMT). During EMT tumour cells acquire a mesenchymal phenotype that is responsible for their invasive activities. Consequently, Snail1 expression in colorectal cancer is usually associated with progression and metastasis. Some studies revealed that about 77% of colon cancer samples display Snail1 immunoreactivity both in activated fibroblasts and in carcinoma cells that have undergone EMT. Therefore, expression of this factor in the stroma may indicate how many cells possess the abilities to escape from the primary tumour mass, invade the basal lamina and colonise distant target organs. Blocking snail proteins activity has the potential to avert cancer cell metastasis by interfering with such cellular processes as remodelling of the actin cytoskeleton, migration and invasion, which are clearly associated with the aggressive phenotype of the disease. Moreover, the link between factors from the snail family and cancer stem cells suggests that inhibitory agents may also prove their potency as inhibitors of cancer recurrence. PMID:26557772

  20. Undifferentiated cells in the snail myocardium are capable of DNA synthesis and myodifferentiation.

    PubMed

    Martynova, Marina G; Bystrova, Olga A

    2002-08-01

    Cellular mechanisms of heart-muscle growth in the snail Achatina fulica have been studied using cytophotometry and electron microscopic autoradiography. Cytophotometric DNA measurements showed that the snail cardiomyocytes are mononucleated cells with diploid nuclei. Ultrastructural analysis of the snail myocardium revealed that, in addition to mature myocytes, it contains small roundish undifferentiated cells (UCs) and poorly differentiated muscle cells. EM autoradiography detected silver grains over the nuclei of UCs 2 h after injection of tritiated thymidine ([(3)H]Tdr), while the nuclei of both mature and poorly differentiated myocytes remained unlabeled. In EM autographs of the myocardial tissue fixed 14 days after [(3)H]Tdr administration, labeled myonuclei were evident, which may suggest some myodifferentiation of prelabeled UCs. Many labeled UCs persist for 14 days after a single [(3)H]Tdr injection, suggesting that not all UCs undergo myodifferentiation after passing through the cell cycle, and that those that do not can enter the next cycle. UCs in the snail myocardium presumably provide not only reserve but also stem cells for myocytes. Thus, the heart muscle of the adult snail consists of mononucleated diploid myocytes with blocked proliferative activity and a renewable population of precursor myogenic cells. The results obtained suggest that the growth of this muscle involves a myoblastic mechanism of myogenesis; this mechanism differs from that of vertebrate cardiac muscle growth, which is non-myoblastic-that is, based on proliferation or polyploidization of cardiomyocytes. Evolutionary aspects of cellular mechanisms of the heart-muscle growth are discussed. PMID:12200260

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

    PubMed

    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

    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

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

    PubMed

    Otludil, Birgül; Cengiz, Elif Ipek; Yildirim, M Zeki; Unver, Ozkan; Unlü, Erhan

    2004-08-01

    In this study the great ramshorn snail (Planorbarius corneus), one of the most abundant gastropod of Turkish limnic systems, was investigated to determine the histopathological effects of endosulfan on the digestive gland, foot and mantle under laboratory conditions. Samples were collected from small artificial pools in Karaot at Gelendost-Isparta (southwest of Turkey), where agricultural activities are widespread. The snails were exposed to two sublethal concentrations of endosulfan (0.4 and 0.8 mg/l) for periods of 10, 20 and 30 days. Fifteen snails were kept in 2.5 l glass jars containing dechlorinated tap water and exposed under semi-static test (daily exchange of test water). All the testing was carried out on adult specimens, and snails were maintained on a photothermal period with 16 light hours at 22 +/- 2 degrees C. The histopathological examinations revealed the following changes: amoebocytes infiltration, dilatation in hemolymphatic spaces between the tubules, degeneration of cells, abnormal lumen, necrosis of cells and atrophy in the connective tissue of digestive gland; desquamation of the epithelium cells, changes in the number of mucocytes and protein gland cells, lipid vacuolus and atrophy of the columnar muscle fibers of the foot and mantle tissues. Pycnotic state of cells was also seen in the mantle tissues. Endosulfan caused significant histopathological alterations in the digestive gland, foot and mantle tissues of the snail, irrespective of concentrations of the pesticide and its exposure periods. The results are discussed, particularly in comparison to those of other aquatic organisms. PMID:15234168

  3. [Ephaptic feedback in identified synapses of terrestrial snails].

    PubMed

    Bravarenko, N I; Malayshev, A Iu; Voronin, L L; Balaban, P M

    2004-01-01

    A hypothesis for the existence of the intrasynaptic ephaptic feedback (EFB) in the invertebrate central nervous sytem was tested. Excitatory postsynaptic potentials (EPSPs) and currents (EPSCs) evoked by the activation of the recently described monosynaptic connection between the identified snail neurons were recorded intracellularly. In case of the EFB presence, the postsynaptic tetanization with hyperpolarization pulses could activate presynaptic Ca2+ channels and enhance the EPSP amplitude, whereas a steady postsynaptic hyperpolarization should induce a "supralinear" increase in EPSC amplitudes as it has been found in the rat hippocampus. In the first series of the experiments, 10 trains of hyperpolarizing pulses (40-50 mV, 1 Hz, pulse duration 0.5 s, train duration 45 s) were delivered postsynaptically. No significant changes in EPSP amplitudes were found. In the second series of the experiments, the EPSC amplitudes were measured during varying postsynaptic hyperpolarization. At the membrane potential 100 mV, the EPSP amplitude was significantly higher than theoretically predicted from the classical linear dependence. Such a "supralinear" effect of postsynaptic depolarization can be explained by the presence of the EFB. This finding is the first evidence for the EFB existence in the invertebrate central nervous system. PMID:15481395

  4. N-glycolylneuraminic acid specific lectin from Pila globosa snail.

    PubMed

    Swarnakar, S; Chowdhury, P S; Sarkar, M

    1991-07-15

    A N-glycolylneuraminic acid-specific lectin (PAL) has been purified from an albumin gland extract of the apple snail, Pila globosa. Purification is conducted on a bovine submaxillary mucin-Sepharose 4B affinity matrix followed by gel filtration on a Sepharose 6B column. The lectin agglutinates rabbit erythrocytes. The hemagglutination activity is dependent on Ca2+ concentration in a significant manner but with a remarkable behaviour. The lectin is a trimeric glycoprotein of native Mr 440 kDa with 25% carbohydrate and is composed of three nonidentical subunits of molecular weights 190, 145, and 105 kDa. It has a pI of 7.0. The lectin exhibits a unique and strict specificity toward N-glycolylneuraminic acid and this phenomenon discriminates it from other known sialic acid binding lectins. The uniqueness indicates the absolute need for a glycolyl substitution on the amino residue and of a glyceryl side chain on the exocyclic part and an axial -COOH group in neuraminic acid. The presence of an acetyl substitution on the exocyclic part impedes lectin-ligand interaction. PMID:1906274

  5. 78 FR 12346 - Jennings Low-Effect Habitat Conservation Plan for the Morro Shoulderband Snail, Community of Los...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ... December 15, 1994 (59 FR 64613). Section 9 of the Endangered Species Act of 1973, as amended (Act) and its... address take of Morro shoulderband snail that is likely to occur as the result of direct impacts to up to...) development and presentation of a contractor and employee training program for Morro shoulderband snail....

  6. Analysis of forkhead and snail expression reveals epithelial-mesenchymal transitions during embryonic and larval development of Nematostella vectensis.

    PubMed

    Fritzenwanker, Jens H; Saina, Michael; Technau, Ulrich

    2004-11-15

    The winged helix transcription factor Forkhead and the zinc finger transcription factor Snail are crucially involved in germ layer formation in Bilateria. Here, we isolated and characterized a homolog of forkhead/HNF3 (FoxA/group 1) and of snail from a diploblast, the sea anemone Nematostella vectensis. We show that Nematostella forkhead expression starts during late Blastula stage in a ring of cells that demarcate the blastopore margin during early gastrulation, thereby marking the boundary between ectodermal and endodermal tissue. snail, by contrast, is expressed in a complementary pattern in the center of forkhead-expressing cells marking the presumptive endodermal cells fated to ingress during gastrulation. In a significant portion of early gastrulating embryos, forkhead is expressed asymmetrically around the blastopore. While snail-expressing cells form the endodermal cell mass, forkhead marks the pharynx anlage throughout embryonic and larval development. In the primary polyp, forkhead remains expressed in the pharynx. The detailed analysis of forkhead and snail expression during Nematostella embryonic and larval development further suggests that endoderm formation results from epithelial invagination, mesenchymal immigration, and reorganization of the endodermal epithelial layer, that is, by epithelial-mesenchymal transitions (EMT) in combination with extensive morphogenetic movements. snail also governs EMT at different processes during embryonic development in Bilateria. Our data indicate that the function of snail in Diploblasts is to regulate motility and cell adhesion, supporting that the triggering of changes in cell behavior is the ancestral role of snail in Metazoa. PMID:15501226

  7. Bioaccumulation and toxicity of copper in outdoor freshwater microcosms.

    PubMed

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

    2011-05-01

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

  8. Human Freshwater Demand for Economic Activity and Ecosystems in Taiwan

    NASA Astrophysics Data System (ADS)

    Ferng, Jiun-Jiun

    2007-12-01

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

  9. Freshwater resources of Big Pine Key, Florida

    USGS Publications Warehouse

    Hanson, Chris E.

    1980-01-01

    The principal freshwater-bearing unit underlying Big Pine Key, Fla, is a layer of oolitic limestone averaging 19 feet in thickness. The freshwater exists in two separate lenses, one in the northern half of the island and one in the southern half. The slightly larger north lens is separated from the south lens by a low-lying land area 1 to 3 feet above mean sea level. The lenses float on saltwater in the aquifer and are affected by tidal fluctuations. The areal and depth configuration of the lenses fluctuate in response to rainfall, evapotranspiration, lateral and vertical losses, and pumpage from local wells. The lenses are not a major source of freshwater. Only a small amount of the freshwater in the lenses can be removed before saltwater intrusion will occur. (USGS)

  10. Best Management Practices for Freshwater Pond Aquaculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. In Brief: Europe's freshwater fish threatened

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2007-11-01

    Two hundred of Europe's 522 freshwater fish species are threatened with extinction and 12 are already extinct, according to the Handbook of European Freshwater Fishes, published in collaboration with the World Conservation Union (IUCN) and released on 1 November 2007. IUCN notes that the main threats to fish species stem from development and population growth and include water withdrawals, large dams, and inappropriate fisheries management that has led to overfishing and the introduction of alien species. Authors Maurice Kottelat, former president of the European Ichthyological Society, and Jörg Freyhof, scientist from Leibniz Institute of Freshwater Ecology, noted that fish conservation should be managed by agencies in charge of conservation, and not as a crop by agencies in charge of agriculture. William Darwall, senior program officer with IUCN's Species Program, said the species ``are critical to the freshwater ecosystems upon which we do depend, such as for water purification and flood control.'' For more information, visit the Web site: http://www.iucn.org.

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

    PubMed Central

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

    2013-01-01

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

  13. Biochemical studies on the terrestrial snail, Eubania vermiculata (Müller) treated with some pesticides.

    PubMed

    el-Wakil, H B; Radwan, M A

    1991-01-01

    The in vivo effects of methomyl, thiodicarb and metaldehyde on total soluble proteins, total lipids and glycogen content, in addition, the activity of glutamic oxaloacetic transaminase, (GOT), (GPT) glutamic pyruvic transaminase and catalase (CAT) enzymes of terrestrial E. vermiculata snails was studied. The experimental snails were treated with low concentration of 0.2% brain bait w/w of the pesticides for a period of 1,3,5,7 and 10 days. The results showed that methomyl and thiodicarb lead to significant reduction in total soluble proteins, lipids, and glycogen content, while significant increases in the activity of all enzymes tested were noted. Metaldehyde treatment showed no significant effect on total soluble proteins, lipids and GOT level, whereas a significant increase in GPT and CAT enzymes was observed. Also, metaldehyde resulted a significant reduction in glycogen content of snails. PMID:1779124

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  16. Differential spatial repositioning of activated genes in Biomphalaria glabrata snails infected with Schistosoma mansoni.

    PubMed

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

    2014-09-01

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

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

    PubMed Central

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

    2012-01-01

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

  18. Snail shape and growth rates: Evidence for plastic shell allometry in Littorina littorea

    PubMed Central

    Kemp, Paul; Bertness, Mark D.

    1984-01-01

    The periwinkle Littorina littorea exhibits morphological variation among southern New England populations that appear to be genetically continuous. In dense populations, individuals have relatively elongate shells in comparison to individuals in sparse populations, which have rounder, globose shells. We experimentally demonstrate that this shell variation is a function of snail growth rate. Rapidly growing snails develop thin, globose shells that accommodate more body mass than thicker, more elongate shells. The implications of these results are discussed in relation to interpreting morphological variation in extant gastropods and in the molluscan fossil record. PMID:16593415

  19. Paraphyly and budding speciation in the hairy snail (Pulmonata, Hygromiidae)

    PubMed Central

    Kruckenhauser, Luise; Duda, Michael; Bartel, Daniela; Sattmann, Helmut; Harl, Josef; Kirchner, Sandra; Haring, Elisabeth

    2014-01-01

    Delimitation of species is often complicated by discordance of morphological and genetic data. This may be caused by the existence of cryptic or polymorphic species. The latter case is particularly true for certain snail species showing an exceptionally high intraspecific genetic diversity. The present investigation deals with the Trochulus hispidus complex, which has a complicated taxonomy. Our analyses of the COI sequence revealed that individuals showing a T. hispidus phenotype are distributed in nine highly differentiated mitochondrial clades (showing p-distances up to 19%). The results of a parallel morphometric investigation did not reveal any differentiation between these clades, although the overall variability is quite high. The phylogenetic analyses based on 12S, 16S and COI sequences show that the T. hispidus complex is paraphyletic with respect to several other morphologically well-defined Trochulus species (T. clandestinus, T. villosus, T. villosulus and T. striolatus) which form well-supported monophyletic groups. The nc marker sequence (5.8S–ITS2–28S) shows only a clear separation of T. o. oreinos and T. o. scheerpeltzi, and a weakly supported separation of T. clandestinus, whereas all other species and the clades of the T. hispidus complex appear within one homogeneous group. The paraphyly of the T. hispidus complex reflects its complicated history, which was probably driven by geographic isolation in different glacial refugia and budding speciation. At our present state of knowledge, it cannot be excluded that several cryptic species are embedded within the T. hispidus complex. However, the lack of morphological differentiation of the T. hispidus mitochondrial clades does not provide any hints in this direction. Thus, we currently do not recommend any taxonomic changes. The results of the current investigation exemplify the limitations of barcoding attempts in highly diverse species such as T. hispidus. PMID:25170185

  20. Commissioned Review. Carbon: freshwater plants

    USGS Publications Warehouse

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

    1992-01-01

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

  1. Evolution of the Freshwater Eels

    NASA Astrophysics Data System (ADS)

    Aoyama, Jun; Tsukamoto, Katsumi

    The freshwater anguillid eels have an unusual life history and world-wide distribution. Questions about the phylogenetic relationships of this group and how their long spawning migrations and larval phase may contribute to their global distribution have not been addressed. This paper is first presentation of molecular phylogeny of Anguilla species, and based on this phylogenetic tree we suggest new aspect of the evolution of this group. Namely, ancestral eels originated during the Eocene or earlier, in the western Pacific Ocean near present-day Indonesia. A group derived from this ancestor dispersed westward, probably by larval transport in the global circum-equatorial current through the northern edge of the Tethys Sea. This group split into the ancestor of the European and American eels, which entered into the Atlantic Ocean, and a second group, which dispersed southward and split into the east African species and Australian species. Thus the world-wide distribution of the eel family can be understood from knowledge of continental drift, ocean currents, a specialized larva and evolutionary forces favoring dispersal and speciation of segregated gene pool.

  2. Global estimation of freshwater fluxes and freshwater oceanic transport from satellite data

    SciTech Connect

    Gautier, C.; Peterson, P.; Jones, C.

    1996-12-01

    The exchange of moisture and heat fluxes across the ocean-atmosphere interface exerts a strong influence on the oceanic and atmospheric circulations, and therefore on the maintenance of the climate system equilibrium. Observational measurements of these fluxes over large areas of the ocean`s surface are limited by the lack of in-situ data. This paper reports research efforts to estimate the freshwater budget and freshwater oceanic transport using remotely sensed data. Six years (1988--1993) of surface evaporation estimated with satellite and in-situ data re combined with satellite-derived precipitation to compute the freshwater budget and freshwater oceanic transport. The interannual variability of the freshwater budget and oceanic transport eliminates are examined for two contrasting events: the La Nina of 1988--89 and the El Nino condition during 1991--92, one of the longest El Nino episodes on record. Possible implications for future climate change are discussed.

  3. Extraction of Freshwater and Energy from Atmosphere

    E-print Network

    Alexander Bolonkin

    2007-04-19

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

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

    PubMed Central

    2014-01-01

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

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

    USGS Publications Warehouse

    Mitchell, A.J.; Cole, R.A.

    2008-01-01

    The faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid-Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large-scale mortality among water birds, primarily in the Great Lakes region and Montana. It is important to limit the spread of the faucet snail; small fisheries equipment can serve as a method of snail distribution. Treatments with chemical disinfection, pH extremes, and heated water baths were tested to determine their effectiveness as a disinfectant for small fisheries equipment. Two treatments eliminated all test snails: (1) a 24-h exposure to Hydrothol 191 at a concentration of at least 20 mg/L and (2) a treatment with 50??C heated water for 1 min or longer. Faucet snails were highly resistant to ethanol, NaCl, formalin, Lysol, potassium permanganate, copper sulfate, Baquacil, Virkon, household bleach, and pH extremes (as low as 1 and as high as 13).

  6. Stable isotope ecology of land snails from a high-latitude site near Fairbanks, interior Alaska, USA

    NASA Astrophysics Data System (ADS)

    Yanes, Yurena

    2015-05-01

    Land snails have been investigated isotopically in tropical islands and mid-latitude continental settings, while high-latitude locales, where snails grow only during the summer, have been overlooked. This study presents the first isotopic baseline of live snails from Fairbanks, Alaska (64°51?N), a proxy calibration necessary prior to paleoenvironmental inferences using fossils. ?13C values of the shell (- 10.4 ± 0.4‰) and the body (- 25.5 ± 1.0‰) indicate that snails consumed fresh and decayed C3-plants and fungi. A flux-balance mixing model suggests that specimens differed in metabolic rates, which may complicate paleovegetation inferences. Shell ?18O values (- 10.8 ± 0.4‰) were ~ 4‰ higher than local summer rain ?18O. If calcification occurred during summer, a flux-balance mixing model suggests that snails grew at temperatures of ~ 13°C, rainwater ?18O values of ~- 15‰ and relative humidity of ~ 93%. Results from Fairbanks were compared to shells from San Salvador (Bahamas), at 24°51?N. Average (annual) ?18O values of shells and rainwater samples from The Bahamas were both ~ 10‰ 18O-enriched with respect to seasonal (summer) Alaskan samples. At a coarse latitudinal scale, shell ?18O values overwhelmingly record the signature of the rainfall during snail active periods. While tropical snails record annual average environmental information, high-latitude specimens only trace summer season climatic data.

  7. Snail2 directly represses cadherin6B during epithelial-to-mesenchymal transitions of the neural crest

    PubMed Central

    Taneyhill, Lisa A.; Coles, Edward G.; Bronner-Fraser, Marianne

    2008-01-01

    The neural crest, a transient population of migratory cells, forms the craniofacial skeleton and peripheral nervous system, among other derivatives in vertebrate embryos. The transcriptional repressor Snail2 is thought to be crucial for the epithelial-to-mesenchymal transition (EMT) that promotes neural crest delamination from the neural tube; however, little is known about its downstream targets. To this end, we depleted avian Snail2 in the premigratory neural crest using morpholino antisense oligonucleotides and examined effects on potential targets by quantitative PCR. Several dorsal neural tube genes were upregulated by alleviating Snail2 repression; moreover, the cell adhesion molecule cadherin6B was derepressed within 30 minutes of blocking Snail2 translation. Examination of the chick cadherin6B genomic sequence reveals that the regulatory region contains three pairs of clustered E boxes, representing putative Snail2 binding sites. Furthermore, in vivo and in vitro biochemical analyses demonstrate that Snail2 directly binds to these sites and regulates cadherin6B transcription. These results are the first to describe a direct target of Snail2 repression in vivo and in the context of the EMT that characterizes neural crest development. PMID:17344227

  8. Conservation status of freshwater gastropods of Canada and the United States

    USGS Publications Warehouse

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

    2013-01-01

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

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

    PubMed Central

    Price, Melissa R.; Hadfield, Michael G.

    2014-01-01

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

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

    PubMed Central

    2014-01-01

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

  11. Field and laboratory evaluation of the influence of copper-diquat on apple snails in southern Florida

    USGS Publications Warehouse

    Winger, P.V.; Imlay, M.J.; McMillan, W.E.; Martin, T.W.; Takekawa, J.; Johnson, W.W.

    1984-01-01

    The recent decline of apple snail (Pomacea paludosa) populations in canals surrounding Loxahatchee National Wildlife Refuge in southern Florida coincided with the use of copper-diquat for the control of the aquatic weed hydrilla (Hydrilla ver/icillara). Field and laboratory studies were designed to assess the effects of copper-diquat on apple snails, which are the primary food of the endangered snail kite Rostrhamus sociabilis (formerly known as the Everglade kite). Acute toxicities (96-h LC50 values) of Cutrine-Plus and Komeen (chelated formulations of copper) to immature apple snails were 22 and 241-?g/L, respectively. Diquat was toxic at a concentration of 1,800 I-?g/L and did not increase the toxicity of copper when the chemicals were used in combination. Evaluation of field samples indicated that copper concentrations were higher in detritus than in water. plants and mud, and that there was a gradient of copper concentration from the canal to the interior, the highest residues being in samples from the canal. Copper associated with detritus (up to 150 ?g/g) had no effect on growth or survival of apple snails in field cage and tank studies. Also, field applications of copper.diquat to hydrilla had no effect on survival of caged adult and immature snails. Copper from field applications was rapidly taken out of solution by plants and organic material in the water and subsequently incorporated into the bottom detritus. Although the effects of repeated applications of copper-diquat and high body burdens of copper (accumulated during exposure to herbicidal treatment) on survival and reproduction of apple snails are not known, the information available indicates that treatment of hydrilla with copper-diquat was probably not responsible for the decline in the apple snail population. Application at recommended rates should pose no threat to these snails in the organically rich waters of southern Florida.

  12. Greenland Freshwater Input to the North Atlantic

    NASA Astrophysics Data System (ADS)

    Beaird, N.; Straneo, F.

    2014-12-01

    The Greenland Ice Sheet (GrIS) is losing mass at an unprecedented rate. The associated increased freshwater flux directly contributes to sea level rise, but also has dynamical implications for the Atlantic Meridional Overturning Circulation and global climate. The freshwater buoyancy forcing from marine terminating outlet glaciers is distributed throughout the depth of coastal fjords. When coupled with strong fjord stratification, this buoyancy forcing can drive significant water mass transformation (WMT) of subsurface waters in the fjord. The WMT differs substantially from a simple freshwater input to the surface ocean. This often overlooked small-scale overturning has potentially important consequences for the influence of GrIS freshwater on large scale ocean circulation and needs to be accounted for in studies of GrIS impact on the ocean. From ship-based and moored hydrographic measurements in East Greenland (2008 to 2013) we describe the character and temporal variability of meltwater driven WMT. While melting always adds freshwater to the ocean, the corresponding WMT causes a seasonally variable vertical redistribution of heat and salt. Observations show that the seasonal cycle of the WMT lags surface air temperatures by several months. We discuss how the WMT and its timing might impact the boundary current system in East Greenland, and implications for its representation in numerical models and impact on North Atlantic deep convection.

  13. Reconsolidation of a Context Long-Term Memory in the Terrestrial Snail Requires Protein Synthesis

    ERIC Educational Resources Information Center

    Gainutdinova, Tatiana H.; Tagirova, Rosa R.; Ismailova, Asja I.; Muranova, Lyudmila N.; Samarova, Elena I.; Gainutdinov, Khalil L.; Balaban, Pavel M.

    2005-01-01

    We investigated the influence of the protein synthesis blocker anisomycin on contextual memory in the terrestrial snail "Helix." Prior to the training session, the behavioral responses in two contexts were similar. Two days after a session of electric shocks (5 d) in one context only, the context conditioning was observed as the significant…

  14. NF-?B and Snail1a coordinate the cell cycle with gastrulation

    PubMed Central

    Liu, Xiaolin; Huang, Sizhou; Ma, Jun; Li, Chun; Zhang, Yaoguang

    2009-01-01

    The cell cycle needs to strictly coordinate with developmental processes to ensure correct generation of the body plan and different tissues. However, the molecular mechanism underlying the coordination remains largely unknown. In this study, we investigate how the cell cycle coordinates gastrulation cell movements in zebrafish. We present a system to modulate the cell cycle in early zebrafish embryos by manipulating the geminin-Cdt1 balance. Alterations of the cell cycle change the apoptotic level during gastrulation, which correlates with the nuclear level of antiapoptotic nuclear factor ?B (NF-?B). NF-?B associates with the Snail1a promoter region on the chromatin and directly activates Snail1a, an important factor controlling cell delamination, which is the initial step of mesendodermal cell movements during gastrulation. In effect, the cell cycle coordinates the delamination of mesendodermal cells through the transcription of Snail1a. Our results suggest a molecular mechanism by which NF-?B and Snail1a coordinate the cell cycle through gastrulation. PMID:19307597

  15. Insights into the origins of fish hunting in venomous cone snails from studies of Conus tessulatus

    PubMed Central

    Aman, Joseph W.; Imperial, Julita S.; Ueberheide, Beatrix; Zhang, Min-Min; Aguilar, Manuel; Taylor, Dylan; Watkins, Maren; Yoshikami, Doju; Showers-Corneli, Patrice; Safavi-Hemami, Helena; Biggs, Jason; Teichert, Russell W.; Olivera, Baldomero M.

    2015-01-01

    Prey shifts in carnivorous predators are events that can initiate the accelerated generation of new biodiversity. However, it is seldom possible to reconstruct how the change in prey preference occurred. Here we describe an evolutionary “smoking gun” that illuminates the transition from worm hunting to fish hunting among marine cone snails, resulting in the adaptive radiation of fish-hunting lineages comprising ?100 piscivorous Conus species. This smoking gun is ?-conotoxin TsVIA, a peptide from the venom of Conus tessulatus that delays inactivation of vertebrate voltage-gated sodium channels. C. tessulatus is a species in a worm-hunting clade, which is phylogenetically closely related to the fish-hunting cone snail specialists. The discovery of a ?-conotoxin that potently acts on vertebrate sodium channels in the venom of a worm-hunting cone snail suggests that a closely related ancestral toxin enabled the transition from worm hunting to fish hunting, as ?-conotoxins are highly conserved among fish hunters and critical to their mechanism of prey capture; this peptide, ?-conotoxin TsVIA, has striking sequence similarity to these ?-conotoxins from piscivorous cone snail venoms. Calcium-imaging studies on dissociated dorsal root ganglion (DRG) neurons revealed the peptide’s putative molecular target (voltage-gated sodium channels) and mechanism of action (inhibition of channel inactivation). The results were confirmed by electrophysiology. This work demonstrates how elucidating the specific interactions between toxins and receptors from phylogenetically well-defined lineages can uncover molecular mechanisms that underlie significant evolutionary transitions. PMID:25848010

  16. Intervention Analysis of Hurricane Effects on Snail Abundance in a Tropical Forest Using

    E-print Network

    Willig, Michael

    Intervention Analysis of Hurricane Effects on Snail Abundance in a Tropical Forest Using Long disturbances, such as hurricanes, have profound effects on pop- ulations, either directly by causing mortality of resources. In the last 20 years, two major disturbances, Hurricane Hugo in 1989 and Hurricane Georges

  17. Tropical sea snail shells: Possible exotic sources for ceramic biomaterial synthesis

    SciTech Connect

    Oktar, F. N.; Kiyici, I. A.; Gökçe, H.; A?aogullar?, D.; Kayali, E. S.

    2013-12-16

    In this study, chemical and structural properties of sea snail shell based bioceramic materials (i.e. hydroxyapatite, whitlockite and other phases) are produced by using mechano-chemical (ultrasonic) conversion method. For this purpose, differential thermal and gravimetric analysis (DTA/TG), X-ray diffraction, infra-red (IR) and scanning electron microscope (SEM) studies are performed.

  18. [Effects of reclaiming and cultivation in marshland on Oncomelania snail control].

    PubMed

    Hong, Xian-Lin; Wang, Xin-Ying

    2012-06-01

    The changes of snail situation in the marshlands and the economic benefit of planting were investigated after planning sesame on marshlands above 16 meters' elevation in Poyang Lake at drought period in autumn and by comparing three groups, i.e. planting sesame alone, planting sesame plus fertilizing "Rong Bao" (a brand of one fertilizer), and no planting. Results showed that the yields in the groups of planting sesame alone and planting plus fertilizing were 15.5 kg and 19.5 kg per 667 m2, respectively, with the output increasing by 25.81% in the fertilizer group. The net incomes of the two groups of planting sesame were 56.5 Yuan and -36.0 Yuan per 667 m2, respectively. One year after the planting, the living snail densities of the three groups were decreased by 97.86%, 100% and 47.62%, respectively. It is suggested that planting sesame on marshlands with snails in Poyang Lake region has a preferable economic benefit and snail control effect. PMID:23012971

  19. Schistosomiasis, also known as bilharzia or "snail fever," is a parasitic disease carried by

    E-print Network

    Davis, Richard E.

    water snails infected with five varieties of the parasite Schistosoma. Found predomi- nantly in tropical and sub-tropical climates, schistosomiasis infects 207 million people in 74 countries worldwide, including schistosomiasis causes scarring and tearing of the bladder and kidneys, and can lead to blad- der cancer

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

    E-print Network

    Yandell, Mark

    Specialized insulin is used for chemical warfare by fish-hunting cone snails Helena Safavi a venom component targeting energy me- tabolism, a radically different mechanism. Two fish-hunting cone evidence suggests that insulin is specifically used as a weapon for prey capture by a subset of fish-hunting

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

    E-print Network

    Grosberg, Rick

    in the evolution of male parental care. Keywords Conflict, gastropod, mating system, parental care, paternity-Brock 1991), presumably because males in most species maximise their reproductive success by desertingLETTER Exclusive male care despite extreme female promiscuity and low paternity in a marine snail

  2. 76 FR 31866 - Endangered and Threatened Wildlife and Plants; Reclassification of the Tulotoma Snail From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ... in the Federal Register on June 22, 2010 (75 FR 35424). The tulotoma snail (Tulotoma magnifica... Coosa River drainage (56 FR 797; January 9, 1991). These included approximately a 3-kilometer (km) (1.8... species prior to June 22, 2010, are outlined in our proposed rule for this reclassification (75 FR...

  3. Drought, snails, and large-scale die-off of southern U.S. salt marshes.

    PubMed

    Silliman, Brian R; van de Koppel, Johan; Bertness, Mark D; Stanton, Lee E; Mendelssohn, Irving A

    2005-12-16

    Salt marshes in the southeastern United States have recently experienced massive die-off, one of many examples of widespread degradation in marine and coastal ecosystems. Although intense drought is thought to be the primary cause of this die-off, we found snail grazing to be a major contributing factor. Survey of marsh die-off areas in three states revealed high-density fronts of snails on die-off edges at 11 of 12 sites. Exclusion experiments demonstrated that snails actively converted marshes to exposed mudflats. Salt addition and comparative field studies suggest that drought-induced stress and grazers acted synergistically and to varying degrees to cause initial plant death. After these disturbances, snail fronts formed on die-off edges and subsequently propagated through healthy marsh, leading to cascading vegetation loss. These results, combined with model analyses, reveal strong interactions between increasing climatic stress and grazer pressure, both potentially related to human environmental impacts, which amplify the likelihood and intensity of runaway collapse in these coastal systems. PMID:16357258

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

    SciTech Connect

    Jay, E.A.

    1993-10-01

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

  5. Larval development of Angiostrongylus vasorum in the land snail Helix aspersa.

    PubMed

    Di Cesare, Angela; Crisi, Paolo Emidio; Bartolini, Roberto; Iorio, Raffaella; Talone, Tonino; Filippi, Laura; Traversa, Donato

    2015-10-01

    The metastrongyloid nematode Angiostrongylus vasorum affects the heart and pulmonary arteries of dogs and wild animals. Over the recent years, dog angiostrongylosis has gained great attention in the veterinary community for the expansion of its geographic range and for a rise in the number of clinical cases. Global warming, changes in phenology of mollusc intermediate hosts and movements of wild reservoirs have been evocated in the spreading of mollusc-borne parasites, including A. vasorum. The land snail Helix aspersa, a vector of other respiratory metastrongyloids, is endemic in most regions of the World, where it is a pest outside its native Mediterranean range. In the present study, the susceptibility and suitability of H. aspersa as an intermediate host of A. vasorum were investigated along with the characteristics of larval recovery and development following two different ways of inoculation, i.e. experimental (group A) vs natural infection (group B). After infections, the snails were kept at environmental conditions for 2 months. Five snails from groups A and B were randomly selected, digested and examined at 15-day intervals for 2 months. L1s, L2s and L3s were microscopically identified based on key morphological and morphometric characteristics and their identity was genetically confirmed. The results showed that A. vasorum may reach the infective stage in H. aspersa and that uptake of larvae and parasitic burden within the snails depend on the grazing capability of the molluscs. Biological and epidemiological implications are discussed. PMID:26122991

  6. Nitric Oxide Inhibits Metamorphosis in Larvae of Crepidula fornicata, the Slippershell Snail

    E-print Network

    Nitric Oxide Inhibits Metamorphosis in Larvae of Crepidula fornicata, the Slippershell Snail JAN A metamorphosis in the marine gastropod Crepidula fornicata. Metamorphosis was stimulated by the nitric oxide) at concentrations of about 100­1000 mol l 1 and 50­200 mol l 1 , respectively. Metamorphosis was not, however

  7. Annotated Checklist of the Aquatic snails of the Mariana Islands, Micronesia

    E-print Network

    Mcilwain, Jenny

    , Micronesia. The Mariana Islands are small (10 to 540 km2 ) volcanic or tectonically uplifted limestoneAnnotated Checklist of the Aquatic snails of the Mariana Islands, Micronesia by Alexander M Kerr known from the Mariana Islands, with notes on taxonomy, physical description, biology and distribution

  8. The identity, distribution, and impacts of non-native apple snails in the continental United States

    PubMed Central

    Rawlings, Timothy A; Hayes, Kenneth A; Cowie, Robert H; Collins, Timothy M

    2007-01-01

    Background Since the mid 1990s populations of non-native apple snails (Ampullariidae) have been discovered with increasing frequency in the continental United States. Given the dramatic effects that introduced apple snails have had on both natural habitats and agricultural areas in Southeast Asia, their introduction to the mainland U.S. is cause for concern. We combine phylogenetic analyses of mtDNA sequences with examination of introduced populations and museum collections to clarify the identities, introduced distributions, geographical origins, and introduction histories of apple snails. Results Based on sampling to date, we conclude there are five species of non-native apple snails in the continental U.S. Most significantly, we recognize three species within what has been called the channeled apple snail: Pomacea canaliculata (California and Arizona), Pomacea insularum, (Florida, Texas, and Georgia) and Pomacea haustrum (Florida). The first established populations of P. haustrum were discovered in the late 1970s in Palm Beach County Florida, and have not spread appreciably in 30 years. In contrast, populations of P. insularum were established in Texas by 1989, in Florida by the mid to late 1990s, and in Georgia by 2005, and this species continues to spread rapidly. Most introduced P. insularum haplotypes are a close match to haplotypes from the Río Uruguay near Buenos Aires, indicating cold tolerance, with the potential to spread from Florida, Georgia, and Texas through Louisiana, Alabama, Mississippi, and South Carolina. Pomacea canaliculata populations were first discovered in California in 1997. Haplotypes of introduced P. canaliculata match native-range haplotypes from near Buenos Aires, Argentina, also indicating cold tolerance and the potential to establish farther north. Conclusion The term "channeled apple snail" is descriptive of a morphology found in many apple snail species. It does not identify a single species or a monophyletic group. Clarifying species identifications permits a more accurate assessment of introduction histories and distributions, and provides a very different picture of the tempo and pattern of invasions than was inferred when the three species with channeled sutures were considered one. Matching introduced and native-range haplotypes suggests the potential for range expansion, with implications for native aquatic ecosystems and species, agriculture, and human health. PMID:17594487

  9. The glycosyltransferase LARGE2 is repressed by Snail and ZEB1 in prostate cancer

    PubMed Central

    Huang, Qin; Miller, Michael R; Schappet, James; Henry, Michael D

    2015-01-01

    Reductions in both expression of the dystroglycan core protein and functional glycosylation of the ?-dystroglycan (?DG) subunit have been reported in a number of cancers and may contribute to disease progression. In the case of prostate cancer, one mechanism that contributes to ?DG hypoglycosylation is transcriptional down-regulation of LARGE2 (GYLTY1B), a glycosyltransferase that produces the functional (laminin-binding) glycan on ?DG, but the mechanism(s) underlying reduction of LARGE2 mRNA remain unclear. Here, we show that ?DG hypoglycosylation is associated with epithelial-to-mesenchymal transition (EMT)-like status. We examined immunoreactivity for both functionally-glycosylated ?DG and E-cadherin by flow cytometry and the relative expression of ZEB1 mRNA and the ?DG glycosyltransferase LARGE2 mRNA in prostate and other cancer cell lines by quantitative RT-PCR. To study the role of ZEB1 and other transcription factors in the regulation of LARGE2, we employed overexpression and knockdown approaches. Snail- or ZEB1-driven EMT caused ?DG hypoglycosylation by repressing expression of the LARGE2 mRNA, with both ZEB1-dependent and -independent mechanisms contributing to Snail-mediated LARGE2 repression. To examine the direct regulation of LARGE2 by Snail and ZEB1 we employed luciferase reporter and chromatin immunoprecipitation assays. Snail and ZEB1 were found to bind directly to the LARGE2 promoter, specifically to E/Z-box clusters. Furthermore, analysis of gene expression profiles of clinical samples in The Cancer Genome Atlas reveals negative correlation of LARGE2 and ZEB1 expression in various cancers. Collectively, our results suggest that LARGE2 is negatively regulated by Snail and/or ZEB1, revealing a mechanistic basis for ?DG hypoglycosylation during prostate cancer progression and metastasis. PMID:25455932

  10. Molecular Diversity and Gene Evolution of the Venom Arsenal of Terebridae Predatory Marine Snails.

    PubMed

    Gorson, Juliette; Ramrattan, Girish; Verdes, Aida; Wright, Elizabeth M; Kantor, Yuri; Rajaram Srinivasan, Ramakrishnan; Musunuri, Raj; Packer, Daniel; Albano, Gabriel; Qiu, Wei-Gang; Holford, Mandë

    2015-06-01

    Venom peptides from predatory organisms are a resource for investigating evolutionary processes such as adaptive radiation or diversification, and exemplify promising targets for biomedical drug development. Terebridae are an understudied lineage of conoidean snails, which also includes cone snails and turrids. Characterization of cone snail venom peptides, conotoxins, has revealed a cocktail of bioactive compounds used to investigate physiological cellular function, predator-prey interactions, and to develop novel therapeutics. However, venom diversity of other conoidean snails remains poorly understood. The present research applies a venomics approach to characterize novel terebrid venom peptides, teretoxins, from the venom gland transcriptomes of Triplostephanus anilis and Terebra subulata. Next-generation sequencing and de novo assembly identified 139 putative teretoxins that were analyzed for the presence of canonical peptide features as identified in conotoxins. To meet the challenges of de novo assembly, multiple approaches for cross validation of findings were performed to achieve reliable assemblies of venom duct transcriptomes and to obtain a robust portrait of Terebridae venom. Phylogenetic methodology was used to identify 14 teretoxin gene superfamilies for the first time, 13 of which are unique to the Terebridae. Additionally, basic local algorithm search tool homology-based searches to venom-related genes and posttranslational modification enzymes identified a convergence of certain venom proteins, such as actinoporin, commonly found in venoms. This research provides novel insights into venom evolution and recruitment in Conoidean predatory marine snails and identifies a plethora of terebrid venom peptides that can be used to investigate fundamental questions pertaining to gene evolution. PMID:26025559

  11. Effects of shorebird predation and snail abundance on an intertidal mudflat community

    NASA Astrophysics Data System (ADS)

    Cheverie, Anne V.; Hamilton, Diana J.; Coffin, Michael R. S.; Barbeau, Myriam A.

    2014-09-01

    Top-down effects of predation are well documented in a variety of ecological communities, including marine soft-sediment systems. It has been proposed that intertidal mudflats in the upper Bay of Fundy, Canada, which host a large population of foraging shorebirds each summer, may exhibit this community dynamic. Biofilm (consisting mainly of diatoms) forms the base of the mudflat community food web, which is dominated by the amphipod Corophium volutator. To assess the potential for a trophic cascade, we conducted a manipulative field experiment examining individual and combined effects of the shorebird Calidris pusilla, a primary predator of C. volutator, and the eastern mudsnail (Nassarius obsoletus), an intraguild predator, on community structure (including macrofauna and large meiofauna retained by a 250-?m screen). Snails exhibited density-dependent top-down effects, primarily from strong negative interactions with juvenile and adult C. volutator, likely due to interference, consumption and emigration. Medium and high densities of snails reduced chlorophyll a concentration (a measure of diatom abundance), likely through consumption and disturbance of the sediment. When present at higher densities, snails also increased variability in community structure. Shorebirds were less influential in determining community structure. They reduced C. volutator biomass through consumption, but there was no resulting effect on primary production. Top-down effects of snails and birds were cumulative on C. volutator, but did not generate a trophic cascade. We suggest that a combination of omnivory and intraguild predation by shorebirds and snails, coupled with relatively low grazing pressure by C. volutator, prevented transmission of top-down effects.

  12. Soil Calcium Availability Influences Shell Ecophenotype Formation in the Sub-Antarctic Land Snail, Notodiscus hookeri

    PubMed Central

    Charrier, Maryvonne; Marie, Arul; Guillaume, Damien; Bédouet, Laurent; Le Lannic, Joseph; Roiland, Claire; Berland, Sophie; Pierre, Jean-Sébastien; Le Floch, Marie; Frenot, Yves; Lebouvier, Marc

    2013-01-01

    Ecophenotypes reflect local matches between organisms and their environment, and show plasticity across generations in response to current living conditions. Plastic responses in shell morphology and shell growth have been widely studied in gastropods and are often related to environmental calcium availability, which influences shell biomineralisation. To date, all of these studies have overlooked micro-scale structure of the shell, in addition to how it is related to species responses in the context of environmental pressure. This study is the first to demonstrate that environmental factors induce a bi-modal variation in the shell micro-scale structure of a land gastropod. Notodiscus hookeri is the only native land snail present in the Crozet Archipelago (sub-Antarctic region). The adults have evolved into two ecophenotypes, which are referred to here as MS (mineral shell) and OS (organic shell). The MS-ecophenotype is characterised by a thick mineralised shell. It is primarily distributed along the coastline, and could be associated to the presence of exchangeable calcium in the clay minerals of the soils. The Os-ecophenotype is characterised by a thin organic shell. It is primarily distributed at high altitudes in the mesic and xeric fell-fields in soils with large particles that lack clay and exchangeable calcium. Snails of the Os-ecophenotype are characterised by thinner and larger shell sizes compared to snails of the MS- ecophenotype, indicating a trade-off between mineral thickness and shell size. This pattern increased along a temporal scale; whereby, older adult snails were more clearly separated into two clusters compared to the younger adult snails. The prevalence of glycine-rich proteins in the organic shell layer of N. hookeri, along with the absence of chitin, differs to the organic scaffolds of molluscan biominerals. The present study provides new insights for testing the adaptive value of phenotypic plasticity in response to spatial and temporal environmental variations. PMID:24376821

  13. A new calibration curve for carbonate clumped isotope thermometer of land snail shells (aragonite)

    NASA Astrophysics Data System (ADS)

    Zhang, N.; Yamada, K.; Yoshida, N.

    2013-12-01

    Clumped isotope data (?47) of carbonate is considered as a useful tool to reflect both the temperature and oxygen isotopic composition of water where the carbonate grew [1]. Zarrur et al. reported the relationship between snail shell calcification temperatures and the mean annual/ activity season ambient temperatures based on a calibration curve established by Ghosh et al. [2]. However, the clumped isotope temperature is always higher than the environment temperature. For better understanding this phenomenon, we present a new empirical calibration curve based on land snail shells (aragonite) cultured in the controlled temperature environment. In 2012, we cultured the land snails ';Euhadra' which were collected from Yokohama, Japan. They were cultured from eggs to adults around 6-8 months under the temperature of 20°, 25° and 30°, respectively. Each temperature group contains 15-20 snails. All of them were fed by cabbages during their life span. To study the effect of ingested carbonate, some of them were fed by Ca3(PO4)2 powder while others were fed by CaCO3 powder. Clumped isotope data for all samples were analyzed by a Thermo Finnigan MAT 253 Mass Spectrometer and calibrated by an ';absolute reference frame' [3]. We found an empirical linear relationship between ?47 and controlled ambient temperature, which is slightly deviated from the published theoretical and experimental calibration curves based on both inorganic and biogenic materials. We will discuss the potential controlling factors caused this kind of deviation combine with the land snail growth environment. [1] Ghosh et al., 2006, Geochimica et Cosmochimica Acta. 70, 1439-1456 [2] Zaarur et al. 2011. Geochimica et Cosmochimica Acta, 75, 6859-6869 [3] Dennis et al., 2011. Geochimica et Cosmochimica Acta 75, 7117-7131

  14. Molecular Diversity and Gene Evolution of the Venom Arsenal of Terebridae Predatory Marine Snails

    PubMed Central

    Gorson, Juliette; Ramrattan, Girish; Verdes, Aida; Wright, Elizabeth M.; Kantor, Yuri; Rajaram Srinivasan, Ramakrishnan; Musunuri, Raj; Packer, Daniel; Albano, Gabriel; Qiu, Wei-Gang; Holford, Mandë

    2015-01-01

    Venom peptides from predatory organisms are a resource for investigating evolutionary processes such as adaptive radiation or diversification, and exemplify promising targets for biomedical drug development. Terebridae are an understudied lineage of conoidean snails, which also includes cone snails and turrids. Characterization of cone snail venom peptides, conotoxins, has revealed a cocktail of bioactive compounds used to investigate physiological cellular function, predator-prey interactions, and to develop novel therapeutics. However, venom diversity of other conoidean snails remains poorly understood. The present research applies a venomics approach to characterize novel terebrid venom peptides, teretoxins, from the venom gland transcriptomes of Triplostephanus anilis and Terebra subulata. Next-generation sequencing and de novo assembly identified 139 putative teretoxins that were analyzed for the presence of canonical peptide features as identified in conotoxins. To meet the challenges of de novo assembly, multiple approaches for cross validation of findings were performed to achieve reliable assemblies of venom duct transcriptomes and to obtain a robust portrait of Terebridae venom. Phylogenetic methodology was used to identify 14 teretoxin gene superfamilies for the first time, 13 of which are unique to the Terebridae. Additionally, basic local algorithm search tool homology-based searches to venom-related genes and posttranslational modification enzymes identified a convergence of certain venom proteins, such as actinoporin, commonly found in venoms. This research provides novel insights into venom evolution and recruitment in Conoidean predatory marine snails and identifies a plethora of terebrid venom peptides that can be used to investigate fundamental questions pertaining to gene evolution. PMID:26025559

  15. Dispersion Of Crude Oil And Petroleum Products In Freshwater

    EPA Science Inventory

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

  16. FRESHWATER INFLOWS: WATER FOR HEALTHY ESTUARIES CONFERENCE (MX96476507

    EPA Science Inventory

    The grantee will hold an interstate workshop on Freshwater Inflow issues in the Gulf of Mexico coastal region. The conference will identify water management questions to be addressed regarding providing freshwater inflows to estuaries, update participants on the current scientif...

  17. ASSESSING MACROINVERTEBRATE BIODIVERSITY IN FRESHWATER ECOSYSTEMS: ADVANCES AND CHALLENGES IN

    E-print Network

    Pfrender, Michael

    ASSESSING MACROINVERTEBRATE BIODIVERSITY IN FRESHWATER ECOSYSTEMS: ADVANCES AND CHALLENGES IN DNA, biodiversity, freshwater, next-generation sequencing abstract Assessing the biodiversity of macroinvertebrate. The accuracy and precision of biodiversity assessments based on standard morphological identifications

  18. Snail Mediates E-Cadherin Repression by the Recruitment of the Sin3A/Histone Deacetylase 1 (HDAC1)/HDAC2 Complex

    PubMed Central

    Peinado, Hector; Ballestar, Esteban; Esteller, Manel; Cano, Amparo

    2004-01-01

    The transcription factor Snail has been described as a direct repressor of E-cadherin expression during development and carcinogenesis; however, the specific mechanisms involved in this process remain largely unknown. Here we show that mammalian Snail requires histone deacetylase (HDAC) activity to repress E-cadherin promoter and that treatment with trichostatin A (TSA) is sufficient to block the repressor effect of Snail. Moreover, overexpression of Snail is correlated with deacetylation of histones H3 and H4 at the E-cadherin promoter, and TSA treatment in Snail-expressing cells reverses the acetylation status of histones. Additionally, we demonstrate that Snail interacts in vivo with the E-cadherin promoter and recruits HDAC activity. Most importantly, we demonstrate an interaction between Snail, histone deacetylase 1 (HDAC1) and HDAC2, and the corepressor mSin3A. This interaction is dependent on the SNAG domain of Snail, indicating that the Snail transcription factor mediates the repression by recruitment of chromatin-modifying activities, forming a multimolecular complex to repress E-cadherin expression. Our results establish a direct causal relationship between Snail-dependent repression of E-cadherin and the modification of chromatin at its promoter. PMID:14673164

  19. Effects of Pollution on Freshwater Organisms.

    PubMed

    Choudri, B S; Baawain, Mahad

    2015-10-01

    This review includes works published in the general scientific literature during 2014 on the effects of anthropogenic pollutants on freshwater organisms. It begins with two broad sections: research reviews and broad field studies and surveys. This is followed by reviews of research categorized in sections to reflect the pollutant class. These sections include wastewater, stormwater and non-point source pollution, nutrients, sediment cap materials and suspended clays, botanical extracts, surfactants, metals, persistent organic pollutants, pharmaceuticals, endocrine disruptors, pesticides, petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), ionic liquids, and nanomaterials. The final section includes works describing innovations in the field of freshwater pollution research. PMID:26420103

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

    E-print Network

    Fong, Derek Allen

    1988-01-01

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

  1. 40 CFR 35.1605-2 - Freshwater lake.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Freshwater lake. 35.1605-2 Section 35.1605-2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Cooperative Agreements for Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-2 Freshwater lake. Any...

  2. The Schistosoma indicum species group in Nepal: presence of a new lineage of schistosome and use of the Indoplanorbis exustus species complex of snail hosts.

    PubMed

    Devkota, Ramesh; Brant, Sara V; Loker, Eric S

    2015-11-01

    From 2007-2014, 19,360 freshwater snails from the Terai and Hilly regions of Nepal were screened for cercariae of mammalian schistosomes. Based on analysis of mitochondrial cytochrome oxidase I, 12S, 16S and 28S sequences (3,675bp) of the cercariae recovered, we provide, to our knowledge, the first report of the Schistosoma indicum species group in Nepal. Five samples of Schistosoma nasale, nine of Schistosoma spindale and 17 of Schistosoma sp. were recovered, all from the snail Indoplanorbis exustus. The last-mentioned lineage failed to group in any of our analyses with S. nasale, S. spindale or S. indicum. It diverged in cox1 sequence from them by 16%, 13% and 13%, respectively, levels of difference comparable to well-studied species pairs of Schistosoma. Analysis of cox1, 16S and internal transcribed spacer 1 sequences (1,874bp) for Nepalese specimens of I. exustus was also surprising in revealing the presence of four genetically distinct clades. They diverged from one another at levels comparable to those noted for species pairs in the sister genus Bulinus. There was no obvious pattern of use by Nepalese Schistosoma of the Indoplanorbis clades. We found high support for a close relationship between S. indicum and Schistosoma haematobium groups, but failed to retrieve support for a clean separation of the two, with a tendency for S. nasale to fall as the most basal representative. If this pattern holds, hypotheses for the origin of the Asian Indoplanorbis-transmitted S. indicum group from the Bulinus-transmitted S. haematobium group may require modification, including consideration of more contemporaneous origins of the two groups. The Indian subcontinent is under-studied with respect to schistosome diversity and our current knowledge of the S. indicum and I. exustus species groups is inadequate. Further study is warranted given the ability of indicum group species to cause veterinary problems and cercarial dermatitis, with a worrisome potential in the future to establish infections in humans. PMID:26385438

  3. Trematodes in snails near raccoon latrines suggest a final host role for this mammal in California Salt Marshes

    USGS Publications Warehouse

    Lafferty, K.D.; Dunham, E.J.

    2005-01-01

    Of the 18 trematode species that use the horn snail, Cerithidea californica, as a first intermediate host, 6 have the potential to use raccoons as a final host. The presence of raccoon latrines in Carpinteria Salt Marsh, California, allowed us to investigate associations between raccoons and trematodes in snails. Two trematode species, Probolocoryphe uca and Stictodora hancocki, occurred at higher prevalences in snails near raccoon latrines than in snails away from latrines, suggesting that raccoons may serve as final hosts for these species. Fecal remains indicated that raccoons fed on shore crabs, the second intermediate host for P. uca, and fish, the second intermediate host for S. hancocki. The increase in raccoon populations in the suburban areas surrounding west coast salt marshes could increase their importance as final hosts for trematodes in this system. ?? American Society of Parasitologists 2005.

  4. Structure and Function of the Snail Statocyst System after a 16-Day Flight on Foton-M-2

    NASA Technical Reports Server (NTRS)

    Balaban, P. M.; Malyshev, A. Y.; Zakharov, I. S.; Aseev, N. A.; Bravarenko, N. I.; Ierusalimsky, V. N.; Samarova, A. I.; Vorontzov, D. D.; Popova, Y.; Boyle, R.

    2006-01-01

    In terrestrial gastropod snail Helix lucorum L. we studied the changes after a 16-day exposure to microgravity in: behavior, neural responses to adequate motion stimulation, intersensory interactions between the photosensory pathways and the statocyst receptors, and in expression of the HPeP gene in the statocyst receptors. In behavioral experiments it was found that the latency of body position change to sudden orientation change (flip from horizontal to downwards position) was significantly reduced in the postflight snails. Extracellularly recorded neural responses of the statocyst nerve to adequate motion stimulation in the postflight snails were independent of the motion direction while in the control animals an orientation selectivity was observed. Significant differences in the HPeP gene mRNA expression pattern in the statocyst receptor neurons were observed in postflight (30h) and control snails. Obtained results confirm the possibility to elucidate the influence of microgravity exposure on mechanisms and function of gravireceptors using this simple model animal.

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

    EPA Science Inventory

    ABSTRACT

    Imposex, the development of male sex characteristics by female gonochoristic snails, has been causally associated with exposure to the ubiquitous environmental contaminant tributyltin (TBT). Documentation of imposex distribution indicates that this masculinizat...

  6. Embryo production in a parthenogenetic snail (Potamopyrgus antipodarum) is negatively affected by the presence of other parthenogenetic females

    E-print Network

    Neiman, Maurine

    Embryo production in a parthenogenetic snail (Potamopyrgus antipodarum) is negatively affected daughter production. A laboratory experiment was conducted to determine whether embryo production in par presence, this experiment showed that embryo production is affected by the number of coexisting

  7. Is the interspecific variation of body size of land snails correlated with rainfall in Israel and Palestine?

    NASA Astrophysics Data System (ADS)

    Hausdorf, Bernhard

    2006-11-01

    The hypothesis that body size of land snail species increases with aridity in Israel and Palestine because large snails lose relatively less water due to their lower surface to volume ratio has been investigated. Data on rainfall amplitudes of 84 land snail species in Israel and Palestine and on their body sizes were used to test for interspecific correlations between body size and rainfall. Four methods, means of body sizes in rainfall categories, the midpoint method, the across-species method, and a phylogenetically controlled analysis (CAIC) showed that there is no significant correlation between body size of land snail species and their rainfall amplitude in Israel and Palestine. The lack of an interspecific correlation between body size and rainfall amplitude may be the result of conflicting selective forces on body size.

  8. CXCL1 expression is correlated with Snail expression and affects the prognosis of patients with gastric cancer

    PubMed Central

    XIANG, ZHEN; JIANG, DA-PING; XIA, GUANG-GAI; WEI, ZHE-WEI; CHEN, WEI; HE, YULONG; ZHANG, CHANG-HUA

    2015-01-01

    Gastric cancer (GC) continues to result in a poor survival rate and prognostic biomarkers for the disease are lacking. Chemokine (C-X-C motif) ligand (CXCL1) expression plays a critical role in tumor metastasis, and Snail promotes epithelial-mesenchymal transition (EMT) to promote metastasis. Therefore, the present study aimed to investigate the correlation between CXCL1 and Snail expression and the effect of CXCL1 expression on the survival of patients with GC. CXCL1 and Snail expression in paraffin-embedded tissue sections from 127 patients with GC were each assessed by immunohistochemistry. Cox regression and Kaplan-Meier analyses were performed to evaluate the prognostic significance of CXCL1 and Snail. Evaluation of the association between CXCL1 and Snail expression and clinical characteristics was based on the ?2 test. Spearman's rank correlation coefficient and Fisher's exact test were used to explore the association between CXCL1 and Snail expression in GC tissues. CXCL1 was found to be significantly associated with tumor invasion (P=0.003), tumor-node-metastasis (TNM) staging (P=0.001), tumor size (P=0.013) and lymph node metastasis (P=0.022) in GC. Snail overexpression was also significantly associated with tumor invasion (P=0.001), TNM staging (P=0.005), tumor size (P=0.026), lymph node metastases (P=0.014) and perineural invasion (P=0.009). CXCL1 and Snail expression were independent factors for a worse overall survival rate, as determined by multivariate analysis (P=0.011 and P=0.018; respectively). The combined expression of CXCL1 and Snail resulted in a worse prognosis compared with the other three groups (P=0.005). Furthermore, there was a significantly positive correlation between CXCL1 and Snail expression in GC (r=0.431; P<0.001). The expression of CXCL1 is significantly associated with Snail expression and may be used as a predictive co-biomarker for patient prognosis and tumor aggressiveness in GC. CXCL1 may promote GC metastasis by regulating EMT. PMID:26622871

  9. Effects of Pollution on Freshwater Invertebrates.

    ERIC Educational Resources Information Center

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

    1978-01-01

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

  10. Effects of pollution on freshwater invertebrates

    SciTech Connect

    Buikema

    1982-06-01

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

  11. Freshwater savings from marine protein consumption

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  12. 2008 NWFSC Tidal Freshwater Genetics Results

    SciTech Connect

    David Teel

    2009-05-01

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

  13. Mathematical Explorations: Freshwater Scarcity: A Proportional Representation

    ERIC Educational Resources Information Center

    King, Alessandra

    2014-01-01

    Middle school students' mathematical understanding benefits from connecting mathematics to other content areas in the curriculum. This month's activity explores the issue of the scarcity of freshwater, a natural resource (activity sheets are included). This activity concentrates on the critical areas mentioned in the Common Core State…

  14. Freshwater Biological Traits Database (External Review Draft)

    EPA Science Inventory

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

  15. Macrophytes: Freshwater Forests of Lakes and Rivers.

    ERIC Educational Resources Information Center

    McDermid, Karla J.; Naiman, Robert J.

    1983-01-01

    Physical, chemical, and biological effects on macrophytes (aquatic plants) on the freshwater ecosystem are discussed. Research questions and issues related to these organisms are also discussed, including adaptations for survival in a wet environment, ecological consequences of large-scale macrophyte eradication, seasonal changes in plant…

  16. Analysis of Snail-1, E-Cadherin and Claudin-1 Expression in Colorectal Adenomas and Carcinomas

    PubMed Central

    Bezdekova, Michala; Brychtova, Svetlana; Sedlakova, Eva; Langova, Katerina; Brychta, Tomas; Belej, Kamil

    2012-01-01

    We report the expression of Snail-1, E-cadherin and claudin-1 by indirect immunohistochemistry in colonic neoplasia. Snail-1 is a zinc finger transcription factor expressed in cells that already have undergone almost complete epithelial-mesenchymal transition (EMT) and have already evaded from the tumor. The main mechanism by which Snail induces EMT is downregulation of E-cadherin, of which expression was shown to be frequently downregulated in many different types of tumors, where it accompanies the invasiveness and metastatic behavior of malignant cells. Moreover, Snail-1 may downregulate the expression of claudin-1, a cell-cell adhesion protein which plays a likely role in progression and dissemination during tumorigenesis. Snail-1 was expressed in both carcinoma and adenoma cells with histologically normal epithelium in the mucosa, adjacent to the tumors, without significant differences, and predominant strong intensity of staining. Statistically significant differences were revealed between normal and tumorous epithelium (p = 0.003) at the subcellular level, where the shift of the protein to the cytoplasm with combined cytoplasmic/nuclear or pure cytoplasmic expression was observed. E-cadherin expression was present in 100% of cases of both adenocarcinomas and adenomas, with prevailing strong membranous immunoreactivity and no differences between protein expression in tumors and normal mucosa. Predominating strong positivity of claudin-1 was detected in tumor cells of adenocarcinomas and adenomas. Marked differences were seen in protein localization, where membranous staining, typical for nontumorous epithelium, changed to combined membranous/cytoplasmic expression in adenocarcinomas (p = 0.0001) and adenomas (0.0002), in which cytoplasmic shift was associated with a higher degree of dysplasia. Furthermore, membranous/cytoplasmic localization was more frequent in the carcinoma group (87%) in comparison with adenomas (51%) (p = 0.0001). We conclude that dystopic subcellular localizations of Snail-1 and claudin-1 may participate in changes of cellular morphology and behavior which might be associated with altered effectory pathways of proteins and thus substantially contribute to the cancer development. PMID:22408413

  17. Snail-induced EMT promotes cancer stem cell-like properties in head and neck cancer cells.

    PubMed

    Ota, Ichiro; Masui, Takashi; Kurihara, Miyako; Yook, Jong-In; Mikami, Shinji; Kimura, Takahiro; Shimada, Keiji; Konishi, Noboru; Yane, Katsunari; Yamanaka, Toshiaki; Kitahara, Tadashi

    2016-01-01

    Epithelial-mesenchymal transition (EMT) is a key process involved in the invasion and metastasis of cancer cells. Furthermore, EMT can induce a cancer stem cell (CSC)?like phenotype in a number of tumor types. We demonstrated that Snail is one of the master regulators that promotes EMT and mediates cancer cell migration and invasion in many types of malignancies including head and neck squamous cell carcinoma (HNSCC). In the present study, we investigated the role of Snail in inducing and maintaining CSC-like properties through EMT in HNSCC. We established HNSCC cell lines transfected with Snail. Stem cell markers were evaluated with real-time RT-PCR and western blot analysis. CSC properties were assessed using sphere formation and WST-8 assays as well as chemosensitivity and chick chorioallantoic membrane in vivo invasion assays. Introduction of Snail induced EMT properties in HNSCC cells. Moreover, Snail-induced EMT maintained the CSC-like phenotype, and enhanced sphere formation capability, chemoresistance and invasive ability. These data suggest that Snail could be one of the critical molecular targets for the development of therapeutic strategies for HNSCC. PMID:26498709

  18. Recovery study of cholinesterases and neurotoxic signs in the non-target freshwater invertebrate Chilina gibbosa after an acute exposure to an environmental concentration of azinphos-methyl.

    PubMed

    Cossi, Paula Fanny; Beverly, Boburg; Carlos, Luquet; Kristoff, Gisela

    2015-10-01

    Azinphos-methyl belongs to the class of organophosphate insecticides which are recognized for their anticholinesterase action. It is one of the most frequently used insecticides in the Upper Valley of Río Negro and Río Neuquén in Argentina, where agriculture represents the second most important economic activity. It has been detected in water from this North Patagonian region throughout the year and the maximum concentration found was 22.48 ?g L(-1) during the application period. Chilina gibbosa is a freshwater gastropod widely distributed in South America, particularly in Patagonia, Argentina and in Southern Chile. Toxicological studies performed with C. gibbosa in our laboratory have reported neurotoxicity signs and cholinesterase inhibition after exposure to azinphos-methyl for 48 h. Recovery studies together with characterization of the enzyme and sensitivity of the enzyme to pesticides can improve the toxicological evaluation. However, little is known about recovery patterns in organisms exposed to organophosphates. The aim of the present work was to evaluate the recovery capacity (during 21 days in pesticide-free water) of cholinesterase activity and neurotoxicity in C. gibbosa after 48 h of exposure to azinphos-methyl. Also, lethality and carboxylesterase activity were registered during the recovery period. Regarding enzyme activities, after a 48-h exposure to 20 ?g L(-1) of azinphos-methyl, cholinesterases showed an inhibition of 85% with respect to control, while carboxylesterases were not affected. After 21 days in pesticide-free water, cholinesterases continued to be inhibited (70%). Severe neurotoxicity signs were observed after exposure: 82% of the snails presented lack of adherence to vessels, 11% showed weak adherence, and 96% exhibited an abnormal protrusion of the head-foot region from shell. After 21 days in pesticide-free water, only 15% of the snails presented severe signs of neurotoxicity. However, during the recovery period significant lethality (30%) was registered in treated snails. C. gibbosa is a very sensitive organism to azinphos-methyl. These snails play an important role in the structure and function of aquatic food webs in this region. Thus, a decline of this species' population would probably have an impact on aquatic and non-aquatic communities. Our results show that C. gibbosa is a relevant sentinel species for studying exposure and effects of azinphos-methyl using behavioral and biochemical biomarkers. Neurotoxic behavioral signs are very sensitive, non-destructive biomarkers, which can be easily detected for about one week after acute exposure. Cholinesterse activity is a very useful biomarker showing a high sensitivity and a slow recovery capacity increasing the possibility to indirectly detect organophosphates for long periods after a contaminant event. PMID:26364254

  19. Consequences of Physical Disturbance by Tadpoles and Snails on Chironomid Larvae

    PubMed Central

    Pal, Gargi; Aditya, Gautam; Hazra, Niladri

    2014-01-01

    Indirect interactions among community members impact on organisms. The effects of two snails, banded pond snail, Bellamya bengalensis (Lamarck), and Red-rimmed melania, Melanoides tuberculata (Müller), and tadpoles of Asian common toad, Duttaphrynus melanostictus (Schneider), on nonbiting midge larvae, Chironomus striatipennis Kieffer, were observed in experimental microcosm. Decrease in tube number and tube length of midge larvae was observed compared to control condition due to introduction of selected above mentioned organisms. The direct effects of non-predator organisms on the midge larvae are due to physical disturbance that destroys their tubes. This may result in vulnerability of midge larvae to predators in the wild. So the community structure may be altered by indirect effects, where one or more species, through their direct disturbance, indirectly change the abundance of other species. PMID:24672384

  20. Factors controlling carbon isotopic composition of land snail shells estimated from lab culturing experiment

    NASA Astrophysics Data System (ADS)

    Zhang, Naizhong; Yamada, Keita; Yoshida, Naohiro

    2014-05-01

    Carbon isotopic composition (?13C) of land snail shell carbonate is widely applied in reconstructing the C3/C4 vegetation distribution of paleo-environment, which is considered to reflect variations of some environmental parameters [1][2][3]. Land snail shell carbon has three potential sources: diet, atmospheric CO2 and ingested carbonate (limestone) [4]. However, their relative contributions to shell carbonate have not been understood well yet [4][5][6][7][8]. More researches are necessary before we could apply this tool in paleo-environment reconstruction, especially inter-lab culturing experiment. A kind of land snail species, Acusta despecta sieboldiana, was collected at Yokohama, Japan and cultured under suitable environment to lay eggs. The second generations were growing up from eggs to adults around 6-12 months at the temperature of 20°, 25° and 30°, respectively. All of the snails at 25° and 30° and most of those at 20° were fed by cabbage (C3 plant) during their life span while others were fed by corn (C4 plant). To investigate the effect of ingested carbonate, some of them were fed by Ca3(PO4)2 powder while others were fed by CaCO3 powder. ?13C of shells were analyzed by an Isotope Ratio Mass Spectrometry (Thermo Finnigan MAT 253); ?13C of food and snail tissue were measured by a Cavity Ring-Down Spectroscopy (Picarro G1121-i). At the same time, ?13C of eggshell and new born snails were analyzed by a Continuous Flow Isotope Ratio Mass Spectrometry (GasBench II). We confirmed that diet, atmospheric CO2 and ingested limestone could be important sources controlling shell ?13C values. And the temperature could affect shell carbonate ?13C values, too. A simple but credible frame was raised to discuss the mechanism of how each possible source and environmental parameter could affect shell carbonate ?13C values based on previous works [4][6][8] and this study. According to this frame and some reasonable assumptions, we have estimated the contribution of different carbon sources for each snail individual: to cabbage (C3 plant) fed groups, the contributions of diet, atmospheric CO2 and ingested limestone vary in a range of 66~80%, 16~24% and 0~13%, respectively. And to corn (C4 plant) fed groups, because of the possible food stress (lower consumption ability of C4 plant), they vary in 56~64%, 18~20% and 16~26%, respectively. We will discuss how these results could be consistent to the observations, which suggests our calculations are suitable and believable. In addition, we will discuss the carbon isotope fractionation during egg laying and hatching of land snails, too. [1] Goodfriend, 1992, Quaternary Sciences Reviews. 11, 665-685 [2] Yanes et al. 2009. Geochimica et Cosmochimica Acta, 73, 4077-4099 [3] Yanes et al., 2013. Palaeogeography, Plaeoclimatology, Palaeoecology, 378, 91-102 [4] Goodfriend and Hood, 1983. Radiocarbon, 25, 810-830 [5] Goodfriend and Stipp, 1983. Geology, 11, 575-577 [6] Stott, 2002. Earth and Planetary Science Letters, 195, 249-259 [7] Metref et al., 2003. Earth and Planetary Science Letters, 211, 381-393 [8] Romaniello et al., 2008. Quaternary Geochronology, 3, 68-75

  1. The complete mitochondrial genome of Chinese land snail Mastigeulota kiangsinensis (Gastropoda: Pulmonata: Bradybaenidae).

    PubMed

    Deng, Pu-Juan; Wang, Wen-Min; Huang, Xiao-Chen; Wu, Xiao-Ping; Xie, Guang-Long; Ouyang, Shan

    2016-03-01

    Mastigeulota kiangsinensis is an endemic and widespread land snail in China. The complete mitochondrial genome of M. kiangsinensis was first determined using long PCR reactions and primer walking method (accession number KM083123). The genome has a length of 14,029?bp, containing 37 typical mitochondrial genes (13 protein-coding genes, 22 tRNA genes and 2 rRNA genes). The base composition of the whole heavy strand is A 29.48%, T 37.92%, C 14.38% and G 18.22%. Gene order of M. kiangsinensis is identical to Euhadra herklotsi, but gene rearrangements are found compared with other mitochondrial genomes described in Stylommatophora. tRNA(Thr) is located in COIII, which has not been found in other helicoids so far. This new complete mitochondrial genome can be the basic data for further studies on mitogenome comparison, molecular taxonomy and phylogenetic analysis in land snails and Molluscs at large. PMID:25185698

  2. Postembryonic neurogenesis in the procerebrum of the terrestrial snail, Helix lucorum L

    NASA Technical Reports Server (NTRS)

    Zakharov, I. S.; Hayes, N. L.; Ierusalimsky, V. N.; Nowakowski, R. S.; Balaban, P. M.

    1998-01-01

    Neuronogenesis during posthatching development of the procerebrum of the terrestrial snail Helix lucorum was analyzed using bromodeoxyuridine immunohistochemistry to label proliferating cells. Comparison of the distribution of labeled cells in a series of animals which differed in age at the time of incubation with bromodeoxyuridine, in survival time after incubation, and in age at sacrifice reveals a clear pattern and developmental sequence in neuron origin. First, the proliferating cells are located only at the apical portion of the procerebrum. Second, cells which are produced at any particular age remain, for the most part, confined to a single layer in the procerebrum. Third, as development proceeds, each layer of previously produced neurons is displaced toward the basal part of the procerebrum by the production of additional neurons. Our results suggest that the vast majority of the neurons (probably about 70-80%) of the snail procerebrum are produced during the first 1-2 months of posthatching development.

  3. ALX1 promotes migration and invasion of lung cancer cells through increasing snail expression

    PubMed Central

    Yao, Wei; Liu, Yong; Zhang, Zhuo; Li, Guoquan; Xu, Xiaoying; Zou, Kun; Xu, Yinghui; Zou, Lijuan

    2015-01-01

    Lung cancer is one of the main causes in cancer-related death. Here we reported a novel functional role of Aristaless-like homeobox1 (ALX1) in lung carcinogenesis. Analysis of ALX1 in lung cancer specimens confirms upregulation of ALX1 in lung cancer, especially these with distant metastasis. Moreover, higher level of ALX1 expression is associated with poorer prognosis of lung cancer patients. Ectopic expression of ALX1 significantly promotes lung cancer cell proliferation, migration and invasion, while ALX1 silencing by siRNA significantly inhibits these abilities of lung cancer cells. The functional role of ALX1 is dependent on increasing Snail expression and knockdown of Snail could restrain the role of ALX1. Collectively, we identify critical roles of ALX1 in lung cancer development and progression. These findings may serve as a framework for future investigations designed to more comprehensive determination of ALX1 as a potential therapeutic target. PMID:26722397

  4. Predator-Prey Interactions between Shell-Boring Beetle Larvae and Rock-Dwelling Land Snails

    PubMed Central

    Castillo Cajas, Ruth F.; van Moorsel, Coline H. M.; Kundrata, Robin; Welter-Schultes, Francisco W.; Giokas, Sinos; Schilthuizen, Menno

    2014-01-01

    Drilus beetle larvae (Coleoptera: Elateridae) are specialized predators of land snails. Here, we describe various aspects of the predator-prey interactions between multiple Drilus species attacking multiple Albinaria (Gastropoda: Clausiliidae) species in Greece. We observe that Drilus species may be facultative or obligate Albinaria-specialists. We map geographically varying predation rates in Crete, where on average 24% of empty shells carry fatal Drilus bore holes. We also provide first-hand observations and video-footage of prey entry and exit strategies of the Drilus larvae, and evaluate the potential mutual evolutionary impacts. We find limited evidence for an effect of shell features and snail behavioral traits on inter- and intra-specifically differing predation rates. We also find that Drilus predators adjust their predation behavior based on specific shell traits of the prey. In conclusion, we suggest that, with these baseline data, this interesting predator-prey system will be available for further, detailed more evolutionary ecology studies. PMID:24964101

  5. A twisting story: how a single gene twists a snail? Mechanogenetics.

    PubMed

    Kuroda, Reiko

    2015-11-01

    Left-right (l-r) symmetry breaking and the establishment of asymmetric animal body plan during embryonic development are fundamental questions in nature. The molecular basis of l-r symmetry breaking of snails is a fascinating topic as it is determined by a maternal single handedness-determining locus at a very early developmental stage. This perspective describes the current state of the art of the chiromorphogenesis, mainly based on our own work, i.e. the first step of l-r symmetry breaking, as proven by our "Mechanogenetics", before the start of zygotic gene expression, transfer of chirality information to the cell-fate determining stage, and the expression of nodal at the blastula stage. The Nodal signalling pathway is a common mechanism in vertebrates' chiromorphogenesis in later development. Studies on snails, especially Lymnaea (L.) stagnalis, shall give important insights into the molecular basis of chiromorphogenesis not only in Lophotrochozoa but in vertebrates as well. PMID:26537404

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

    NASA Technical Reports Server (NTRS)

    1998-01-01

    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.

  7. Enrichment and identification of cellulolytic bacteria from the gastrointestinal tract of Giant African snail, Achatina fulica.

    PubMed

    Pawar, Kiran D; Dar, Mudasir A; Rajput, Bharati P; Kulkarni, Girish J

    2015-02-01

    The cellulolytic bacterial community structure in gastrointestinal (GI) tract of Achatina fulica was studied using culture-independent and -dependent methods by enrichment in carboxymethyl cellulose (CMC). Culture-dependent method indicated that GI tract of snail was dominated by Enterobacteriaceae members. When tested for cellulase activities, all isolates obtained by culture-dependent method showed both or either of CMCase or avicelase activity. Isolate identified as Citrobacter freundii showed highest CMCase and medium avicelase activity. Sequencing of clones from the 16S rRNA gene clone library identified ten operational taxonomic units (OTUs), which were affiliated to Enterobacteriaceae of phylum Gammaproteobacteria. Of these ten OTUs, eight OTUs closely matched with Enterobacter and Klebsiella genera. The most abundant OTU allied to Klebsiella oxytoca accounted for 70 % of the total sequences. The members of Klebsiella and Enterobacter were observed by both methods indicating their dominance among the cellulolytic bacterial community in the GI tract of the snail. PMID:25432338

  8. Water snails as paratenic hosts of Hymenolepididae Fuhrmann, 1907 in Czechoslovakia.

    PubMed

    Rysavý, B

    1986-01-01

    The distribution of cysticercoids of Hymenolepididae Fuhrmann, 1907 parasitizing water birds (Anseriformes and Ralliformes) in Czechoslovakia was studied. A total of 2970 snail specimens (429 Lymnaea stagnalis (L.), 531 L. ovata (Drap.), 1, 462 L. peregra (O. F. Müll.), 158 L. auricularia (L.), 262 Planorbis planorbis (L.) and 65 Viviparus viviparus (L.)) were examined for this purpose. Among them, 122 snails were infected with cysticercoids of 13 cestode species (Dicranotaenia coronula (Dujardin, 1845), Diorchis inflata (Rudolphi, 1810), D. nyrocae Yamaguti, 1935, D. ransomi Schultz, 1940, Diploposthe laevis (Bloch, 1782), Echinocotyle rosetteri Blanchard, 1891, Fimbriaria fasciolaris (Pallas, 1781), Microsomacanthus compressa (Linton 1892), M. paracompressa (Czaplinski, 1956), M. paramicrosoma (Gasowska, 1931), M. spiralibursata (Czaplinski, 1956), Sobolevicanthus gracilis (Zeder, 1803), and S. octacantha (Krabbe, 1869). PMID:3758867

  9. Consequences of physical disturbance by tadpoles and snails on chironomid larvae.

    PubMed

    Pal, Gargi; Aditya, Gautam; Hazra, Niladri

    2014-01-01

    Indirect interactions among community members impact on organisms. The effects of two snails, banded pond snail, Bellamya bengalensis (Lamarck), and Red-rimmed melania, Melanoides tuberculata (Müller), and tadpoles of Asian common toad, Duttaphrynus melanostictus (Schneider), on nonbiting midge larvae, Chironomus striatipennis Kieffer, were observed in experimental microcosm. Decrease in tube number and tube length of midge larvae was observed compared to control condition due to introduction of selected above mentioned organisms. The direct effects of non-predator organisms on the midge larvae are due to physical disturbance that destroys their tubes. This may result in vulnerability of midge larvae to predators in the wild. So the community structure may be altered by indirect effects, where one or more species, through their direct disturbance, indirectly change the abundance of other species. PMID:24672384

  10. Ocean acidification increases the vulnerability of native oysters to predation by invasive snails.

    PubMed

    Sanford, Eric; Gaylord, Brian; Hettinger, Annaliese; Lenz, Elizabeth A; Meyer, Kirstin; Hill, Tessa M

    2014-03-01

    There is growing concern that global environmental change might exacerbate the ecological impacts of invasive species by increasing their per capita effects on native species. However, the mechanisms underlying such shifts in interaction strength are poorly understood. Here, we test whether ocean acidification, driven by elevated seawater pCO?, increases the susceptibility of native Olympia oysters to predation by invasive snails. Oysters raised under elevated pCO? experienced a 20% increase in drilling predation. When presented alongside control oysters in a choice experiment, 48% more high-CO? oysters were consumed. The invasive snails were tolerant of elevated CO? with no change in feeding behaviour. Oysters raised under acidified conditions did not have thinner shells, but were 29-40% smaller than control oysters, and these smaller individuals were consumed at disproportionately greater rates. Reduction in prey size is a common response to environmental stress that may drive increasing per capita effects of stress-tolerant invasive predators. PMID:24430847

  11. Concentration and retention of Toxoplasma gondii oocysts by marine snails demonstrate a novel mechanism for transmission of terrestrial zoonotic pathogens in coastal ecosystems

    USGS Publications Warehouse

    Krusor, Colin; Smith, Woutrina A.; Tinker, M. Tim; Silver, Mary; Conrad, Patricia A.; Shapiro, Karen

    2015-01-01

    The parasite Toxoplasma gondii is an environmentally persistent pathogen that can cause fatal disease in humans, terrestrial warm-blooded animals and aquatic mammals. Although an association between T.?gondii exposure and prey specialization on marine snails was identified in threatened California sea otters, the ability of kelp-dwelling snails to transmit terrestrially derived pathogens has not been previously investigated. The objective of this study was to measure concentration and retention of T.?gondii by marine snails in laboratory aquaria, and to test for natural T.?gondii contamination in field-collected snails. Following exposure to T.?gondii-containing seawater, oocysts were detected by microscopy in snail faeces and tissues for 10 and 3 days respectively. Nested polymerase chain reaction was also applied as a method for confirming putative T.?gondii oocysts detected in snail faeces and tissues by microscopy. Toxoplasma gondiiwas not detected in field-collected snails. Results suggest that turban snails are competent transport hosts for T.?gondii. By concentrating oocysts in faecal pellets, snails may facilitate entry of T.?gondii into the nearshore marine food web. This novel mechanism also represents a general pathway by which marine transmission of terrestrially derived microorganisms can be mediated via pathogen concentration and retention by benthic invertebrates.

  12. Concentration and retention of Toxoplasma gondii oocysts by marine snails demonstrate a novel mechanism for transmission of terrestrial zoonotic pathogens in coastal ecosystems.

    PubMed

    Krusor, Colin; Smith, Woutrina A; Tinker, M Tim; Silver, Mary; Conrad, Patricia A; Shapiro, Karen

    2015-11-01

    The parasite Toxoplasma gondii is an environmentally persistent pathogen that can cause fatal disease in humans, terrestrial warm-blooded animals and aquatic mammals. Although an association between T.?gondii exposure and prey specialization on marine snails was identified in threatened California sea otters, the ability of kelp-dwelling snails to transmit terrestrially derived pathogens has not been previously investigated. The objective of this study was to measure concentration and retention of T.?gondii by marine snails in laboratory aquaria, and to test for natural T.?gondii contamination in field-collected snails. Following exposure to T.?gondii-containing seawater, oocysts were detected by microscopy in snail faeces and tissues for 10 and 3 days respectively. Nested polymerase chain reaction was also applied as a method for confirming putative T.?gondii oocysts detected in snail faeces and tissues by microscopy. Toxoplasma gondii was not detected in field-collected snails. Results suggest that turban snails are competent transport hosts for T.?gondii. By concentrating oocysts in faecal pellets, snails may facilitate entry of T.?gondii into the nearshore marine food web. This novel mechanism also represents a general pathway by which marine transmission of terrestrially derived microorganisms can be mediated via pathogen concentration and retention by benthic invertebrates. PMID:26033089

  13. Adaptation of Lymnaea fuscus and Radix balthica to Fasciola hepatica through the experimental infection of several successive snail generations

    PubMed Central

    2014-01-01

    Background High prevalence of Fasciola hepatica infection (>70%) was noted during several outbreaks before the 2000s in several French farms where Galba truncatula is lacking. Other lymnaeids such as Lymnaea fuscus, L. glabra and/or Radix balthica are living in meadows around these farms but only juvenile snails can sustain complete larval development of F. hepatica while older snails were resistant. The low prevalence of infection (<20%) and limited cercarial production (<50 cercariae per infected snail) noted with these juveniles could not explain the high values noted in these cattle herds. As paramphistomosis due to Calicophoron daubneyi was not still noted in these farms, the existence of another mode of infection was hypothesized. Experimental infection of several successive generations of L. glabra, originating from eggs laid by their parents already infected with this parasite resulted in a progressive increase in prevalence of snail infection and the number of shed cercariae. The aim of this paper was to determine if this mode of snail infection was specific to L. glabra, or it might occur in other lymnaeid species such as L. fuscus and R. balthica. Methods Five successive generations of L. fuscus and R. balthica were subjected to individual bimiracidial infections in the laboratory. Resulting rediae and cercariae in the first four generations were counted after snail dissection at day 50 p.e. (20°C), while the dynamics of cercarial shedding was followed in the F5 generation. Results In the first experiment, prevalence and intensity of F. hepatica infection in snails progressively increased from the F1 (R. balthica) or F2 (L. fuscus) generation. In the second experiment, the prevalence of F. hepatica infection and the number of shed cercariae were significantly lower in L. fuscus and R. balthica (without significant differences between both lymnaeids) than in G. truncatula. Conclusion The F. hepatica infection of several successive snail generations, coming from parents infected with this parasite, resulted in a progressive increase in prevalence and intensity of snail infection. This may explain high prevalence of fasciolosis noted in several cattle-breeding farms when the common snail host of this digenean, G. truncatula, is lacking. PMID:24986589

  14. Land Snails as a Diet Diversification Proxy during the Early Upper Palaeolithic in Europe

    PubMed Central

    Fernández-López de Pablo, Javier; Badal, Ernestina; Ferrer García, Carlos; Martínez-Ortí, Alberto; Sanchis Serra, Alfred

    2014-01-01

    Despite the ubiquity of terrestrial gastropods in the Late Pleistocene and Holocene archaeological record, it is still unknown when and how this type of invertebrate resource was incorporated into human diets. In this paper, we report the oldest evidence of land snail exploitation as a food resource in Europe dated to 31.3-26.9 ka yr cal BP from the recently discovered site of Cova de la Barriada (eastern Iberian Peninsula). Mono-specific accumulations of large Iberus alonensis land snails (Ferussac 1821) were found in three different archaeological levels in association with combustion structures, along with lithic and faunal assemblages. Using a new analytical protocol based on taphonomic, microX-Ray Diffractometer (DXR) and biometric analyses, we investigated the patterns of selection, consumption and accumulation of land snails at the site. The results display a strong mono-specific gathering of adult individuals, most of them older than 55 weeks, which were roasted in ambers of pine and juniper under 375°C. This case study uncovers new patterns of invertebrate exploitation during the Gravettian in southwestern Europe without known precedents in the Middle Palaeolithic nor the Aurignacian. In the Mediterranean context, such an early occurrence contrasts with the neighbouring areas of Morocco, France, Italy and the Balkans, where the systematic nutritional use of land snails appears approximately 10,000 years later during the Iberomaurisian and the Late Epigravettian. The appearance of this new subsistence activity in the eastern and southern regions of Spain was coeval to other demographically driven transformations in the archaeological record, suggesting different chronological patterns of resource intensification and diet broadening along the Upper Palaeolithic in the Mediterranean basin. PMID:25141047

  15. EMT transcription factors snail and slug directly contribute to cisplatin resistance in ovarian cancer

    PubMed Central

    2012-01-01

    Background The epithelial to mesenchymal transition (EMT) is a molecular process through which an epithelial cell undergoes transdifferentiation into a mesenchymal phenotype. The role of EMT in embryogenesis is well-characterized and increasing evidence suggests that elements of the transition may be important in other processes, including metastasis and drug resistance in various different cancers. Methods Agilent 4 × 44 K whole human genome arrays and selected reaction monitoring mass spectrometry were used to investigate mRNA and protein expression in A2780 cisplatin sensitive and resistant cell lines. Invasion and migration were assessed using Boyden chamber assays. Gene knockdown of snail and slug was done using targeted siRNA. Clinical relevance of the EMT pathway was assessed in a cohort of primary ovarian tumours using data from Affymetrix GeneChip Human Genome U133 plus 2.0 arrays. Results Morphological and phenotypic hallmarks of EMT were identified in the chemoresistant cells. Subsequent gene expression profiling revealed upregulation of EMT-related transcription factors including snail, slug, twist2 and zeb2. Proteomic analysis demonstrated up regulation of Snail and Slug as well as the mesenchymal marker Vimentin, and down regulation of E-cadherin, an epithelial marker. By reducing expression of snail and slug, the mesenchymal phenotype was largely reversed and cells were resensitized to cisplatin. Finally, gene expression data from primary tumours mirrored the finding that an EMT-like pathway is activated in resistant tumours relative to sensitive tumours, suggesting that the involvement of this transition may not be limited to in vitro drug effects. Conclusions This work strongly suggests that genes associated with EMT may play a significant role in cisplatin resistance in ovarian cancer, therefore potentially leading to the development of predictive biomarkers of drug response or novel therapeutic strategies for overcoming drug resistance. PMID:22429801

  16. FMRF-amide is a glucose-lowering hormone in the snail Helix aspersa.

    PubMed

    R?szer, Tamás; Kiss-Tóth, Éva D

    2014-11-01

    Although glucose is metabolically the most important carbohydrate in almost all living organisms, still little is known about the evolution of the hormonal control of cellular glucose uptake. In this study, we identify Phe-Met-Arg-Phe-amide (FMRFa), also known as molluscan cardioexcitatory tetrapeptide, as a glucose-lowering hormone in the snail Helix aspersa. FMRFa belongs to an evolutionarily conserved neuropeptide family and is involved in the neuron-to-muscle signal transmission in the snail digestive system. This study shows that, beyond this function, FMRFa also has glucose-lowering activity. We found neuronal transcription of genes encoding FMRFa and its receptor and moreover the hemolymph FMRFa levels were peaking at metabolically active periods of the snails. In turn, hypometabolism of the dormant periods was associated with abolished FMRFa production. In the absence of FMRFa, the midintestinal gland ("hepatopancreas") cells were deficient in their glucose uptake, contributing to the development of glucose intolerance. Exogenous FMRFa restored the absorption of hemolymph glucose by the midintestinal gland cells and improved glucose tolerance in dormant snails. We show that FMRFa was released to the hemolymph in response to glucose challenge. FMRFa-containing nerve terminals reach the interstitial sinusoids between the chondroid cells in the artery walls. We propose that, in addition to the known sites of possible FMRFa secretion, these perivascular sinusoids serve as neurohemal organs and allow FMRFa release. This study suggests that in evolution, not only the insulin-like peptides have adopted the ability to increase cellular glucose uptake and can act as hypoglycemic hormones. PMID:25096715

  17. Snailine: a possible diagnostic reagent from a common marine snail, the southern periwinkle, Littorina angulifera.

    PubMed

    Smith, A C

    1986-01-01

    A substance which strongly precipitates human serum proteins is released into the environment by the southern periwinkle, Littorina angulifera. Two-dimensional crossed immunoelectrophoresis revealed that the snail precipitin reacts with a number of human serum proteins, including 11 not detected by mammalian antiserum. The precipitin is readily collected in saline solution, which then is referred to as snailine, a potentially useful diagnostic reagent. Precipitins released into the environment by marine species may represent a little-known external immunologic system. PMID:3817245

  18. Land snails as a diet diversification proxy during the early upper palaeolithic in Europe.

    PubMed

    Fernández-López de Pablo, Javier; Badal, Ernestina; Ferrer García, Carlos; Martínez-Ortí, Alberto; Sanchis Serra, Alfred

    2014-01-01

    Despite the ubiquity of terrestrial gastropods in the Late Pleistocene and Holocene archaeological record, it is still unknown when and how this type of invertebrate resource was incorporated into human diets. In this paper, we report the oldest evidence of land snail exploitation as a food resource in Europe dated to 31.3-26.9 ka yr cal BP from the recently discovered site of Cova de la Barriada (eastern Iberian Peninsula). Mono-specific accumulations of large Iberus alonensis land snails (Ferussac 1821) were found in three different archaeological levels in association with combustion structures, along with lithic and faunal assemblages. Using a new analytical protocol based on taphonomic, microX-Ray Diffractometer (DXR) and biometric analyses, we investigated the patterns of selection, consumption and accumulation of land snails at the site. The results display a strong mono-specific gathering of adult individuals, most of them older than 55 weeks, which were roasted in ambers of pine and juniper under 375°C. This case study uncovers new patterns of invertebrate exploitation during the Gravettian in southwestern Europe without known precedents in the Middle Palaeolithic nor the Aurignacian. In the Mediterranean context, such an early occurrence contrasts with the neighbouring areas of Morocco, France, Italy and the Balkans, where the systematic nutritional use of land snails appears approximately 10,000 years later during the Iberomaurisian and the Late Epigravettian. The appearance of this new subsistence activity in the eastern and southern regions of Spain was coeval to other demographically driven transformations in the archaeological record, suggesting different chronological patterns of resource intensification and diet broadening along the Upper Palaeolithic in the Mediterranean basin. PMID:25141047

  19. Untangling the Ecology, Taxonomy, and Evolution of Chaetogaster limnaei (Oligochaeta: Naididae) Species Complex.

    PubMed

    Smythe, Ashleigh B; Forgrave, Kristin; Patti, Amanda; Hochberg, Rick; Litvaitis, Marian K

    2015-06-01

    Within Oligochaeta, Chaetogaster limnaei is unusual in exhibiting a parasitic relationship with freshwater pulmonate snails. Taxonomic confusion has been caused by differences in what have been considered 2 subspecies of this worm: Chaetogaster limnaei limnaei is an ectosymbiont and is present inside the mantle cavity of the snail, whereas Chaetogaster limnaei vaghini is parasitic and lives in the kidney of the snail. This study explored the distribution of these annelids in central New York and used mitochondrial DNA sequence data from the COI locus to examine the relationship, evolution, and species status of the ectosymbiotic and parasitic forms of C. limnaei. Snails ( Physa gyrina ) were collected from 6 streams and lakes in central New York, with additional specimens collected from a lake in Massachusetts for comparison. One hundred and forty snails were examined, and at least 1 form of Chaetogaster was present in 88 specimens, a prevalence of 62.9%. COI sequence data from New York and Massachusetts did not reveal separate ectosymbiotic and parasitic lineages. Instead, all parasitic forms were part of a mixed clade that included both ectosymbiotic and parasitic forms. This mixed clade was nested within clades of ectosymbiotic forms only, suggesting that a plastic lineage of C. limnaei, able to be both ectosymbionts and parasites, evolved from ectoparasitic ancestors. PMID:25634497

  20. Adjustment of metabolite composition in the haemolymph to seasonal variations in the land snail Helix pomatia.

    PubMed

    Nicolai, Annegret; Filser, Juliane; Lenz, Roman; Bertrand, Carole; Charrier, Maryvonne

    2011-05-01

    In temperate regions, land snails are subjected to subzero temperatures in winter and hot temperatures often associated to drought in summer. The response to these environmental factors is usually a state of inactivity, hibernation and aestivation, respectively, in a temperature and humidity buffered refuge, accompanied by physiological adjustments to resist cold or heat stress. We investigated how environmental factors in the microhabitat and body condition influence the metabolite composition of haemolymph of the endangered species Helix pomatia. We used UPLC and GC-MS techniques and analyzed annual biochemical variations in a multivariate model. Hibernation and activity months differed in metabolite composition. Snails used photoperiod as cue for seasonal climatic variations to initiate a physiological state and were also highly sensitive to temperature variations, therefore constantly adjusting their physiological processes. Galactose levels gave evidence for the persistence of metabolic activity with energy expenditure during hibernation and for high reproductive activity in June. Triglycerides accumulated prior to hibernation might act as cryoprotectants or energy reserves. During the last month of hibernation snails activated physiological processes related to arousal. During activity, protein metabolism was reflected by high amino acid level. An exceptional aestivation period was observed in April giving evidence for heat stress responses, like the protection of cells from dehydration by polyols and saccharides, the membrane stabilization by cholesterol and enhanced metabolism using the anaerobic succinic acid pathway to sustain costly stress responses. In conclusion, physiological adjustments to environmental variations in Helix pomatia involve water loss regulation, cryoprotectant or heatprotectant accumulation. PMID:21136264

  1. Water balance and resistance to desiccation in rock-dwelling snails

    NASA Astrophysics Data System (ADS)

    Arad, Zeev; Goldenberg, Shoshana; Heller, Joseph

    1995-06-01

    We have examined the resistance to desiccation among rock-dwelling land snails of various phylogenetic groups: Cristataria genezarethana (Clausiliidae), Rupestrella rhodia (Chondrinidae) and Levantina caesareana (Helicidae), all from the same location in Israel. L. caesareana was the most resistant and R. rhodia the least resistant to desiccation and C. genezarethana was of intermediate resistance. Differences in the rates of water loss during desiccation were determined mainly by rate of water loss during the first 2 days of desiccation. The high rates of water loss in rock-dwelling species exceed those of other snails in the Mediterranean habitat of Israel. However, snails collected in the field at the end of aestivation were in only a mild state of dehydration, suggesting that the rocky habitat protects its occupants against desiccation. We also suggest that among the rock-dwelling species, the protective role of the rock is more important in the more evolutionarily primitive genera (the chondrinid Rupestrella and the clausiliid Cristataria) and that physiological capacities are more effective in the more highly evolved helicid Levantina.

  2. Evolution of separate predation- and defence-evoked venoms in carnivorous cone snails

    PubMed Central

    Dutertre, Sébastien; Jin, Ai-Hua; Vetter, Irina; Hamilton, Brett; Sunagar, Kartik; Lavergne, Vincent; Dutertre, Valentin; Fry, Bryan G.; Antunes, Agostinho; Venter, Deon J.; Alewood, Paul F.; Lewis, Richard J.

    2014-01-01

    Venomous animals are thought to inject the same combination of toxins for both predation and defence, presumably exploiting conserved target pharmacology across prey and predators. Remarkably, cone snails can rapidly switch between distinct venoms in response to predatory or defensive stimuli. Here, we show that the defence-evoked venom of Conus geographus contains high levels of paralytic toxins that potently block neuromuscular receptors, consistent with its lethal effects on humans. In contrast, C. geographus predation-evoked venom contains prey-specific toxins mostly inactive at human targets. Predation- and defence-evoked venoms originate from the distal and proximal regions of the venom duct, respectively, explaining how different stimuli can generate two distinct venoms. A specialized defensive envenomation strategy is widely evolved across worm, mollusk and fish-hunting cone snails. We propose that defensive toxins, originally evolved in ancestral worm-hunting cone snails to protect against cephalopod and fish predation, have been repurposed in predatory venoms to facilitate diversification to fish and mollusk diets. PMID:24662800

  3. Distribution and abundance of the Japanese snail, Viviparus japonicus, and associated macrobenthos in Sandusky Bay, Ohio

    USGS Publications Warehouse

    Wolfert, David R.; Hiltunen, Jarl K.

    1968-01-01

    A survey of the macrobenthos of Sandusky Bay, Lake Erie, in June, 1963, provided information on the abundance and distribution of the introduced Japanese snail, Viviparus japonicus, which has become a nuisance to commercial seine fishermen. The abundance and distribution varied considerably within the bay; at the time of the survey, most snails were found near the north-central shore. Environmental characteristics were nearly uniform and had no apparent effect on the distribution; concentrations in different areas at different times appeared to result from water movements induced by winds. The time of the study coincided with a period of reproduction; young-of-the-year snails were most abundant in areas where adults were most common. The frequency distributions of shell height and diameter suggested the presence of two age groups of adults in the population. Considerable natural mortality was seen, both at the time of the study and in other seasons. Only three other gastropods were observed in the bay; the most abundant was another viviparid, Campeloma decisum. Other mollusks present were four species of Sphaeriidae and 18 species of Unionidae. A summary of invertebrates found, other than the mollusks, is also presented.

  4. The effect of changes in habitat conditions on the movement of juvenile Snail Kites Rostrhamus sociabilis

    USGS Publications Warehouse

    Bowling, Andrea C.; Martin, Julien; Kitchens, Wiley M.

    2012-01-01

    The degradation of habitats due to human activities is a major topic of interest for the conservation and management of wild populations. There is growing evidence that the Florida Everglades ecosystem continues to suffer from habitat degradation. After a period of recovery in the 1990s, the Snail Kite Rostrhamus sociabilis population suffered a substantial decline in 2001 and has not recovered since. Habitat degradation has been suggested as one of the primary reasons for this lack of recovery. As a consequence of the continued degradation of the Everglades, we hypothesized that this would have led to increased movement of juvenile Kites over time, as a consequence of the need to find more favourable habitat. We used multistate mark-recapture models to compare between-site movement probabilities of juvenile Snail Kites in the 1990s (1992–95; which corresponds to the period before the decline) and 2000s (2003–06; after the decline). Our analyses were based on an extensive radiotelemetry study (266 birds tracked monthly over the entire state of Florida for a total period of 6 years) and considered factors such as sex and age of marked individuals. There was evidence of increased movement of juvenile Snail Kites during the post-decline period from most of the wetland regions used historically by Kites. Higher movement rates may contribute to an increase in the probability of mortality of young individuals and could contribute to the observed declines.

  5. Nitric oxide is necessary for labilization of a consolidated context memory during reconsolidation in terrestrial snails.

    PubMed

    Balaban, Pavel M; Roshchin, Matvey; Timoshenko, Alia K; Gainutdinov, Khalil L; Bogodvid, Tatiana K; Muranova, Lyudmila N; Zuzina, Alena B; Korshunova, Tatiana A

    2014-09-01

    Nitric oxide (NO) is known to be involved in associative memory formation. We investigated the influence of blocking NO function on the reconsolidation of context memory in terrestrial snails (Helix lucorum L.). After a 10 day session of electric shocks in one context only, context memory in snails was observed in test sessions as the significant difference of amplitudes of withdrawal responses to tactile stimuli in two different contexts. After a 1 day rest, a session of 'reminding' was performed, preceded by injection in different groups of the snails with either vehicle or combination of the protein synthesis blocker anisomycin (ANI) with one of the following drugs: the NO scavenger carboxy-PTIO, the NO-synthase inhibitors N-omega-nitro-L-arginin, nitroindazole and NG-nitro-L-arginine methyl ester hydrochloride, or the NO donor S-nitroso-N-acetyl-DL-penicillamine. Testing the context memory at different time intervals after the reminder under ANI injection showed that the context memory was impaired at 24 h and later, whereas the reminder under combined injection of ANI and each of the NO-synthase inhibitors used or the NO scavenger showed no impairment of long-term context memory. Injection of the NO donor S-nitroso-N-acetyl-DL-penicillamine with or without reminder had no effect on context memory. The results obtained demonstrated that NO is necessary for labilization of a consolidated context memory. PMID:24910164

  6. Schistosoma mansoni: a method for inducing resistance to praziquantel using infected Biomphalaria glabrata snails.

    PubMed

    Couto, Flávia F B; Coelho, Paulo Marcos Z; Araújo, Neusa; Kusel, John R; Katz, Naftale; Jannotti-Passos, Liana K; Mattos, Ana Carolina A

    2011-03-01

    To elucidate the mechanisms of antischistosoma resistance, drug-resistant Schistosoma mansoni laboratory isolates are essential. We developed a new method for inducing resistance to praziquantel (PZQ) using successive drug treatments of Biomphalaria glabrata snails infected with S. mansoni. Infected B. glabrata were treated three times with 100 mg/kg PZQ for five consecutive days with a one-week interval between them. After the treatment, the cercariae (LE-PZQ) produced from these snails and the LE strains (susceptible) were used to infect mice. Forty-five days after infection, mice were treated with 200, 400 or 800 mg/kg PZQ. Thirty days post-treatment, we observed that the mean number of worms recovered by perfusion was significantly higher in the group of mice infected with the LE-PZQ isolate treated with 200 and 400 mg/kg in comparison to the LE strain with the same treatment. Moreover, there was a significant difference between the ED50 (effective dose required to kill 50% of the worms) of the LE-PZQ isolate (362 mg/kg) and the LE strain (68 mg/kg). In the in vitro assays, the worms of the LE-PZQ isolate were also less susceptible to PZQ. Thus, the use of infected snails as an experimental model for development of resistance to S. mansoni is effective, fast, simple and cheap. PMID:21537673

  7. Involvement of the Cytokine MIF in the Snail Host Immune Response to the Parasite Schistosoma mansoni

    PubMed Central

    Baeza Garcia, Alvaro; Pierce, Raymond J.; Gourbal, Benjamin; Werkmeister, Elisabeth; Colinet, Dominique; Reichhart, Jean-Marc; Dissous, Colette; Coustau, Christine

    2010-01-01

    We have identified and characterized a Macrophage Migration Inhibitory Factor (MIF) family member in the Lophotrochozoan invertebrate, Biomphalaria glabrata, the snail intermediate host of the human blood fluke Schistosoma mansoni. In mammals, MIF is a widely expressed pleiotropic cytokine with potent pro-inflammatory properties that controls cell functions such as gene expression, proliferation or apoptosis. Here we show that the MIF protein from B. glabrata (BgMIF) is expressed in circulating immune defense cells (hemocytes) of the snail as well as in the B. glabrata embryonic (Bge) cell line that has hemocyte-like features. Recombinant BgMIF (rBgMIF) induced cell proliferation and inhibited NO-dependent p53-mediated apoptosis in Bge cells. Moreover, knock-down of BgMIF expression in Bge cells interfered with the in vitro encapsulation of S. mansoni sporocysts. Furthermore, the in vivo knock-down of BgMIF prevented the changes in circulating hemocyte populations that occur in response to an infection by S. mansoni miracidia and led to a significant increase in the parasite burden of the snails. These results provide the first functional evidence that a MIF ortholog is involved in an invertebrate immune response towards a parasitic infection and highlight the importance of cytokines in invertebrate-parasite interactions. PMID:20886098

  8. Adaptive shell color plasticity during the early ontogeny of an intertidal keystone snail.

    PubMed

    Manríquez, Patricio H; Lagos, Nelson A; Jara, María Elisa; Castilla, Juan Carlos

    2009-09-22

    We report a mechanism of crypsis present during the vulnerable early post-metamorphic ontogeny (snail Concholepas concholepas, a rocky shore keystone predator characteristic of the southeastern Pacific coast. In the field, we found a significant occurrence (>95%) of specimens bearing patterns of shell coloration (dark or light colored) that matched the background coloration provided by patches of Concholepas' most abundant prey (mussels or barnacles respectively). The variation in shell color was positively associated with the color of the most common prey (r = 0.99). In laboratory experiments, shell coloration of C. concholepas depended on the prey-substrate used to induce metamorphosis and for the post-metamorphic rearing. The snail shell color matched the color of the prey offered during rearing. Laboratory manipulation experiments, switching the prey during rearing, showed a corresponding change in snail shell color along the outermost shell edge. As individuals grew and became increasingly indistinguishable from the surrounding background, cryptic individuals had higher survival (71%) than the non cryptic ones (4%) when they were reared in the presence of the predatory crab Acanthocyclus hassleri. These results suggest that the evolution of shell color plasticity during the early ontogeny of C. concholepas, depends on the color of the more abundant of the consumed prey available in the natural habitat where settlement has taken place; this in turn has important consequences for their fitness and survivorship in the presence of visual predators. PMID:19805296

  9. Adaptive shell color plasticity during the early ontogeny of an intertidal keystone snail

    PubMed Central

    Manríquez, Patricio H.; Lagos, Nelson A.; Jara, María Elisa; Castilla, Juan Carlos

    2009-01-01

    We report a mechanism of crypsis present during the vulnerable early post-metamorphic ontogeny (?20 mm peristomal length) of the muricid snail Concholepas concholepas, a rocky shore keystone predator characteristic of the southeastern Pacific coast. In the field, we found a significant occurrence (>95%) of specimens bearing patterns of shell coloration (dark or light colored) that matched the background coloration provided by patches of Concholepas' most abundant prey (mussels or barnacles respectively). The variation in shell color was positively associated with the color of the most common prey (r = 0.99). In laboratory experiments, shell coloration of C. concholepas depended on the prey-substrate used to induce metamorphosis and for the post-metamorphic rearing. The snail shell color matched the color of the prey offered during rearing. Laboratory manipulation experiments, switching the prey during rearing, showed a corresponding change in snail shell color along the outermost shell edge. As individuals grew and became increasingly indistinguishable from the surrounding background, cryptic individuals had higher survival (71%) than the non cryptic ones (4%) when they were reared in the presence of the predatory crab Acanthocyclus hassleri. These results suggest that the evolution of shell color plasticity during the early ontogeny of C. concholepas, depends on the color of the more abundant of the consumed prey available in the natural habitat where settlement has taken place; this in turn has important consequences for their fitness and survivorship in the presence of visual predators. PMID:19805296

  10. FOXM1 Promotes Lung Adenocarcinoma Invasion and Metastasis by Upregulating SNAIL

    PubMed Central

    Wei, Ping; Zhang, Nu; Wang, Yiqin; Li, Dawei; Wang, Lisha; Sun, Xiangjie; Shen, Chen; Yang, Yusi; Zhou, Xiaoyan; Du, Xiang

    2015-01-01

    The forkhead box M1 (FOXM1) transcription factor is one of the key genes inducing tumor invasion and metastasis by an unknown mechanism. In this study, we set out to investigate the effects of FOXM1 overexpression on metastatic human lung adenocarcinoma and the underlying mechanism. FOXM1 expression was analyzed in 78 frozen lung adenocarcinoma tissue samples using an Affymetrix microarray and a 155-paraffin-embedded lung adenocarcinoma tissue microarray with immunohistochemical detection. FOXM1 was found to be overexpressed in lung adenocarcinoma, particularly in metastatic patients, compared to non-metastatic patients. Knockdown of FOXM1 by a specific siRNA significantly suppressed EMT progression, migration and invasion of lung adenocarcinoma cells in vitro, and tumor growth and metastasis in vivo, whereas restored expression of FOXM1 had the opposite effect. FOXM1 binds directly to the SNAIL promoter through two specific binding sites and constitutively transactivates it. Collectively, our findings indicate that FOXM1 may play an important role in advancing lung adenocarcinoma progression. Aberrant FOXM1 expression directly and constitutively activates SNAIL, thereby promoting lung adenocarcinoma metastasis. Inhibition of FOXM1-SNAIL signaling may present an ideal target for future treatment. PMID:25561901

  11. Pharmaceutical bioaccumulation by periphyton and snails in an effluent-dependent stream during an extreme drought.

    PubMed

    Du, Bowen; Haddad, Samuel P; Scott, W Casan; Chambliss, C Kevin; Brooks, Bryan W

    2015-01-01

    Increasing evidence indicates that pharmaceutical bioaccumulate in fish collected downstream from municipal wastewater effluent discharges. However, studies of pharmaceutical bioaccumulation by other aquatic organisms, including primary producers (e.g., periphyton) and grazers (e.g., snails), are lacking in wadeable streams. Here, we examined environmental occurrence and bioaccumulation of a range of pharmaceuticals and other contaminants of emerging concern in surface water, a common snail (Planorbid sp.) and periphyton from an effluent-dependent stream in central Texas, USA, during a historic drought, because such limited dilution and instream flows may represent worst-case exposure scenarios for aquatic life to pharmaceuticals. Water and tissue samples were liquid-liquid extracted and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization. Target analytes included 21 pharmaceuticals across multiple drug classes and 2 pharmacologically active metabolites. Several pharmaceuticals were detected at up to 4.7 ?g kg(-1) in periphyton and up to 42 ?g kg(-1) in Planorbid sp. We then identified limitations of several bioconcentration factor and bioaccumulation factor models, developed for other invertebrates, to assist interpretation of such field results. Observations from the present study suggest that waterborne exposure to pharmaceuticals may be more important than dietary exposure for snails. PMID:25261960

  12. Gender-based differences in Florida apple snail (Pomacea paludosa) movements

    USGS Publications Warehouse

    Valentine-Darby, P. L.; Darby, P.C.; Percival, H.F.

    2011-01-01

    Gastropod movements have been studied in the context of habitat selection, finding food and mates, and avoiding predation. Many of these studies were conducted in the laboratory, where constraints on spatial scale influence behavior. We conducted a field study of Florida apple snail (Pomacea paludosa) movements using telemetry. We hypothesized that Florida apple snail movements were driven by reproductive activity, and that gender differences would be evident. We documented male and female directions and distances traveled. We also conducted a trapping study that included conspecific bait to test if the presence of females attracted more males as measured by M:F ratios in traps. The greatest distances traveled were by males, and males were more likely to maintain a consistent bearing compared to females. Male distances peaked in what typically corresponds to peak breeding season. M:F ratios in traps were positively associated with reproductive activity in the study population as measured by egg cluster counts. Conspecific bait had no effect on the number of males or females captured. However, if a female crawled into the trap, we observed greater numbers of males compared to those with no trapped females. Males may have tracked females to increase mating encounters, following slime trails, as seen in other aquatic (including other Pomacea) snails. The capacity for mate finding has implications for reproductive success in the relatively low density populations often seen for Pomacea paludosa.

  13. Invasiveness Does Not Predict Impact: Response of Native Land Snail Communities to Plant Invasions in Riparian Habitats

    PubMed Central

    Horá?ková, Jitka; Ju?i?ková, Lucie; Šizling, Arnošt L.; Pyšek, Petr

    2014-01-01

    Studies of plant invasions rarely address impacts on molluscs. By comparing pairs of invaded and corresponding uninvaded plots in 96 sites in floodplain forests, we examined effects of four invasive alien plants (Impatiens glandulifera, Fallopia japonica, F. sachalinensis, and F.×bohemica) in the Czech Republic on communities of land snails. The richness and abundance of living land snail species were recorded separately for all species, rare species listed on the national Red List, and small species with shell size below 5 mm. The significant impacts ranged from 16–48% reduction in snail species numbers, and 29–90% reduction in abundance. Small species were especially prone to reduction in species richness by all four invasive plant taxa. Rare snails were also negatively impacted by all plant invaders, both in terms of species richness or abundance. Overall, the impacts on snails were invader-specific, differing among plant taxa. The strong effect of I. glandulifera could be related to the post-invasion decrease in abundance of tall nitrophilous native plant species that are a nutrient-rich food source for snails in riparian habitats. Fallopia sachalinensis had the strongest negative impact of the three knotweeds, which reflects differences in their canopy structure, microhabitat humidity and litter decomposition. The ranking of Fallopia taxa according to the strength of impacts on snail communities differs from ranking by their invasiveness, known from previous studies. This indicates that invasiveness does not simply translate to impacts of invasion and needs to be borne in mind by conservation and management authorities. PMID:25238059

  14. A portable identification guide to invertebrates living in freshwater streams, lakes, creeks and ponds

    E-print Network

    Thorp, James H.

    , Class Turbellaria Chapter 08 Hairworms: Phylum Nematomorpha Chapter 09 Snails: Phylum Mollusca, Class Gastropoda Chapter 10 Mussels and Clams: Phylum Mollusca, Class Bivalvia Chapter 11 Aquatic Segmented Worms

  15. Historical changes in arctic freshwater ecosystems.

    PubMed

    Prowse, Terry D; Wrona, Frederick J; Reist, James D; Gibson, John J; Hobbie, John E; Lévesque, Lucie M J; Vincent, Warwick F

    2006-11-01

    Various types of ecosystem-based climate proxies have been used to assess past arctic change. Although lotic records are relatively poor because of the constant reworking of riverine material, high-quality lentic data have been assembled back to the end of the Pleistocene and deglaciation of the circumpolar Arctic. In general, climatic variations in the Holocene, partly due to changes in the shrinking effect of glacier coverage, produced significant temporal and spatial variations in arctic hydrology and freshwater ecosystems. Of particular note were the vast expansions of northern peatlands during major protracted periods of wetting. More recent lake biota and sedimentiological data reflect the general warming trend that has occurred over the last one to two centuries and indicate major changes to freshwater characteristics such as ice-cover duration and thermal stratification. Such data provide an excellent baseline against which future effects of climate change can be both projected and measured. PMID:17256638

  16. Freshwater aquatic plant biomass production in Florida

    SciTech Connect

    Reddy, K.R.; Sutton, D.L.; Bowes, G.

    1983-01-01

    About 8% (1.2 million ha) of the total surface area of Florida is occupied by freshwater. Many of these water bodies are eutrophic. Nutrients present in these water bodies can be potentially used to culture aquatic plants as a possible feedstock for methane production. This paper summarizes the results of known research findings on biomass production potential of freshwater aquatic plants in Florida and identifies key research needs to improve the quality and quantity of biomass yields. Among floating aquatic plants, biomass yield potential was in the order of water-hyacinth > water lettuce > pennywort > salvinia > duckweed > azolla. Pennywort, duckweed, and azolla appear to perform well during the cooler months compared to other aquatic plants. Among emergent plants, biomass yield potential was in the order of southern wild rice > cattails > soft rush > bulrush. Cultural techniques, nutrient management, and environmental factors influencing the biomass yields were discussed. 68 references.

  17. Superhydrophobic resistance to dynamic freshwater biofouling inception.

    PubMed

    Krishnan, K Ghokulla; Malm, Peter; Loth, Eric

    2015-01-01

    Superhydrophobic nanotextured surfaces have gained increased usage in various applications due to their non-wetting and self-cleaning abilities. The aim of this study was to investigate nanotextured surfaces with respect to their resistance to the inception of freshwater biofouling at transitional flow conditions. Several coatings were tested including industry standard polyurethane (PUR), polytetrafluoroethylene (PTFE), capstone mixed polyurethane (PUR + CAP) and nanocomposite infused polyurethane (PUR + NC). Each surface was exposed to freshwater conditions in a lake at 4 m s(-1) for a duration of 45 min. The polyurethane exhibited the greatest fouling elements, in terms of both height and number of elements, with the superhydrophobic nanocomposite based polyurethane (PUR + NC) showing very little to no fouling. A correlation between the surface characteristics and the degree of fouling inception was observed. PMID:26618394

  18. In Vitro Effects of Mucus from the Mantle of Compatible (Lymnaea elodes) and Incompatible (Helisoma trivolvis) Snail Hosts on Fascioloides magna Miracidia.

    PubMed

    Coyne, Kathyrn; Laursen, Jeffrey R; Yoshino, Timothy P

    2015-06-01

    The epidermal mucus covering the surface of a snail represents an important barrier to trematode larvae attempting to penetrate the snail and may play a role in mediating snail-trematode compatibility. In this study, Facioloides magna miracidia were exposed to mucus harvested from a compatible snail host, Lymnaea elodes (palustris), and from an incompatible snail, Helisoma trivolvis . In vitro treatment of freshly hatched miracidia with snail-derived mucus exerted dramatically different effects on larvae depending on snail species. At the lowest dilution of mucus tested (1:3) mean damage rates (tegumental damage and/or larval lysis and death) were as high as 100% for miracidia exposed to H. trivolvis mucus, while none of F. magna miracidia were damaged in L. elodes mucus. A dilution series for each snail species, and treatments with heat and proteinase K were performed to characterize the component(s) of mucus inducing the observed morphological changes. The damaging effects of H. trivolvis mucus were concentration dependent and completely abrogated by heat (65 C, 30 min) and proteinase treatment, strongly implicating a heat-labile protein(s) in mucus as the active cytotoxic agent(s). In contrast to our prediction that miracidial contact with mucus of compatible L. elodes would trigger larval transformation, mucus from either snail species tested exhibited little to no activity. Overall these data demonstrate the presence of a potent cytotoxic protein-like factor in the mucus of F. magna -incompatible H. trivolvis , and its absence in the mucus of the compatible snail, L. elodes . This finding supports the notion that the epidermal mucus layer may be serving as an important determinant of larval trematode-snail compatibility. PMID:25602486

  19. Urban growth, climate change, and freshwater availability

    PubMed Central

    McDonald, Robert I.; Green, Pamela; Balk, Deborah; Fekete, Balazs M.; Revenga, Carmen; Todd, Megan; Montgomery, Mark

    2011-01-01

    Nearly 3 billion additional urban dwellers are forecasted by 2050, an unprecedented wave of urban growth. While cities struggle to provide water to these new residents, they will also face equally unprecedented hydrologic changes due to global climate change. Here we use a detailed hydrologic model, demographic projections, and climate change scenarios to estimate per-capita water availability for major cities in the developing world, where urban growth is the fastest. We estimate the amount of water physically available near cities and do not account for problems with adequate water delivery or quality. Modeled results show that currently 150 million people live in cities with perennial water shortage, defined as having less than 100 L per person per day of sustainable surface and groundwater flow within their urban extent. By 2050, demographic growth will increase this figure to almost 1 billion people. Climate change will cause water shortage for an additional 100 million urbanites. Freshwater ecosystems in river basins with large populations of urbanites with insufficient water will likely experience flows insufficient to maintain ecological process. Freshwater fish populations will likely be impacted, an issue of special importance in regions such as India's Western Ghats, where there is both rapid urbanization and high levels of fish endemism. Cities in certain regions will struggle to find enough water for the needs of their residents and will need significant investment if they are to secure adequate water supplies and safeguard functioning freshwater ecosystems for future generations. PMID:21444797

  20. Monitoring Global Freshwater Resources with GRACE

    NASA Technical Reports Server (NTRS)

    Rodell, Matt; Famiglietti, Jay; Velicogna, Isabella; Swenson, Sean; Chambers, Don

    2011-01-01

    Freshwater resources include surface waters, groundwater, and seasonal snowpack. Given adequate ground based measurements, all of these can be monitored effectively, however, outside of the developed world such measurements often are not systematic and the data not centralized, and as a result reports of freshwater availability may be largely anecdotal. Even in the developed world it can be difficult to quantify changes in groundwater storage over large scales. Owing to its global coverage, satellite remote sensing has become a valuable tool for freshwater resources assessment. In particular, the Gravity Recovery and Climate Experiment (GRACE) has demonstrated an unequaled ability to monitor total terrestrial water storage including groundwater at regional to continental scales. In this presentation we will identify apparent trends in terrestrial water storage observed by GRACE over the past nine years and attempt to explain their origins and predict whether they are likely to continue. Trends in certain regions where groundwater extraction has significantly depleted aquifers, including northern India and California, will be discussed in detail.

  1. Vegetative community control of freshwater availability: Phoenix Islands case study

    NASA Astrophysics Data System (ADS)

    Engels, M.; Heinse, R.

    2014-12-01

    On small low islands with limited freshwater resources, terrestrial plant communities play a large role in moderating freshwater availability. Freshwater demands of vegetative communities are variable depending on the composition of the community. Hence, changes to community structure from production crop introductions, non-native species invasions, and climate change, may have significant implications for freshwater availability. Understanding how vegetative community changes impact freshwater availability will allow for better management and forecasting of limited freshwater supplies. To better understand these dynamics, we investigated three small tropical atolls in the Phoenix Island Protected Area, Kiribati. Despite their close proximity, these islands receive varying amounts of rainfall, are host to different plant communities and two of the islands have abandoned coconut plantations. Using electromagnetic induction, ground penetrating radar, soil samples, climate and satellite data, we present preliminary estimates of vegetative water demand for different tropical plant communities.

  2. Comparative evaluation of haemagglutination potential of haemolymph from two species of giant African land snails (Archachatina marginata and Achatina achatina).

    PubMed

    Abiona, John Adesanya; Akinduti, Paul Akinniyi; Oyekunle, Mufutao Atanda; Osinowo, Olusegun Ayodeji; Onagbesan, A Okanlawon Mohammed

    2014-05-01

    A comparative study was conducted to evaluate haemagglutination potential in the haemolymph of two species of giant African land snails (Archachatina marginata and Achatina achatina). Three liveweight groups of snails (<100 g, 101-150 g and >150 g) were used with 4 replicates per liveweight per species for haemagglutination assay (HA). The effect of aestivation on haemagglutination potential was also evaluated. Erythrocytes (2%) from cattle, sheep, goat and chicken were used for HA assay. Results showed that agglutinin-like substances that agglutinate erythrocytes of sheep, goat, cattle and chicken were present in the haemolymph of the two species of giant African land snails. Effect of species was found to be significant (P < 0.001) on haemagglutination titre. Haemolymph of A. marginata, had higher haemagglutination titre than that of A. achatina across the three liveweight groups used in this study. Snail liveweight had no significant effect (P > 0.05) on agglutinin content of the haemolymph in both species. Agglutination level depended on the source of erythrocyte used. Sheep erythrocyte recorded the highest haemagglutination titre, followed by goat, cattle, and chicken in that order. To our knowledge, this is the first evidence that Giant African land snails (GALS) haemolymph contain agglutinins as previously reported for Helix species. This evidence may be the basis for its survivability in the wild and thus establish the use of GALS for African herbal medicinal applications. PMID:24657726

  3. Domain analysis of the Nematostella vectensis SNAIL ortholog reveals unique nucleolar localization that depends on the zinc-finger domains

    PubMed Central

    Dattoli, Ada A.; Hink, Mark A.; DuBuc, Timothy Q.; Teunisse, Bram J.; Goedhart, Joachim; Röttinger, Eric; Postma, Marten

    2015-01-01

    SNAIL transcriptional factors are key regulators during development and disease. They arose early during evolution, and in cnidarians such as Nematostella vectensis, NvSNAILA/B are detected in invaginating tissues during gastrulation. The function of SNAIL proteins is well established in bilaterians but their roles in cnidarians remain unknown. The structure of NvSNAILA and B is similar to the human SNAIL1 and 2, including SNAG and zinc-finger domains. Here, we performed a molecular analysis on localization and mobility of NvSNAILA/B using mammalian cells and Nematostella embryos. NvSNAILA/B display nuclear localization and mobility similar to HsSNAIL1/2. Strikingly, NvSNAILA is highly enriched in the nucleoli and shuttles between the nucleoli and the nucleoplasm. Truncation of the N-terminal SNAG domain, reported to contain Nuclear Localization Signals, markedly reduces nucleolar levels, without effecting nuclear localization or mobility. Truncation of the C-terminal zinc-fingers, involved in DNA binding in higher organisms, significantly affects subcellular localization and mobility. Specifically, the zinc-finger domains are required for nucleolar enrichment of NvSNAILA. Differently from SNAIL transcriptional factors described before, NvSNAILA is specifically enriched in the nucleoli co-localizing with nucleolar markers even after nucleolar disruption. Our findings implicate additional roles for SNAG and zinc-finger domains, suggesting a role for NvSNAILA in the nucleolus. PMID:26190255

  4. Involvement of transcription repressor Snail in the regulation of human telomerase reverse transcriptase (hTERT) by transforming growth factor-?.

    PubMed

    Yoo, Young-Sun; Park, Seoyoung; Gwak, Jungsug; Ju, Bong Gun; Oh, Sangtaek

    2015-09-11

    Human telomerase reverse transcriptase (hTERT), a catalytic subunit of telomerase, is the primary determinant for telomerase enzyme activity, which has been associated with cellular immortality. Expression of the hTERT gene is regulated by various extracellular (external) stimuli and is aberrantly up-regulated in more than 90% of cancers. Here we show that hTERT gene expression was repressed in response to transforming growth factor-? (TGF-?) by a mechanism dependent on transcription factors Snail and c-Myc. TGF-? activated Snail and down-regulated c-Myc gene expression. In addition, ectopic expression of Snail strongly inhibited hTERT promoter activity, although co-expression of c-Myc abrogated this effect. Chromatin immunoprecipitation (ChIP) analysis revealed that TGF-? decreased c-Myc occupancy and dramatically increased recruitment of Snail to the E-box motifs of the hTERT promoter, thereby repressing hTERT expression. Our findings suggest a dynamic alteration in hTERT promoter occupancy by Snail and c-Myc is the mechanistic basis for TGF-?-mediated regulation of hTERT. PMID:26235880

  5. Celastrol inhibits TGF-?1-induced epithelial–mesenchymal transition by inhibiting Snail and regulating E-cadherin expression

    SciTech Connect

    Kang, Hyereen; Lee, Minjae; Jang, Sung-Wuk; Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736

    2013-08-09

    Highlights: •We investigated the effects of celastrol on TGF-?1-induced EMT in epithelial cells. •Celastrol regulates TGF-?1-induced morphological changes and E-cadherin expression. •Celastrol inhibits TGF-?1-induced Snail expression. •Celastrol strongly suppresses TGF-?1-induced invasion in MDCK and A549 cells. -- Abstract: The epithelial–mesenchymal transition (EMT) is a pivotal event in the invasive and metastatic potentials of cancer progression. Celastrol inhibits the proliferation of a variety of tumor cells including leukemia, glioma, prostate, and breast cancer; however, the possible role of celastrol in the EMT is unclear. We investigated the effect of celastrol on the EMT. Transforming growth factor-beta 1 (TGF-?1) induced EMT-like morphologic changes and upregulation of Snail expression. The downregulation of E-cadherin expression and upregulation of Snail in Madin–Darby Canine Kidney (MDCK) and A549 cell lines show that TGF-?1-mediated the EMT in epithelial cells; however, celastrol markedly inhibited TGF-?1-induced morphologic changes, Snail upregulation, and E-cadherin expression. Migration and invasion assays revealed that celastrol completely inhibited TGF-?1-mediated cellular migration in both cell lines. These findings indicate that celastrol downregulates Snail expression, thereby inhibiting TGF-?1-induced EMT in MDCK and A549 cells. Thus, our findings provide new evidence that celastrol suppresses lung cancer invasion and migration by inhibiting TGF-?1-induced EMT.

  6. Heavy metal concentrations in a soil-plant-snail food chain along a terrestrial soil pollution gradient.

    PubMed

    Notten, M J M; Oosthoek, A J P; Rozema, J; Aerts, R

    2005-11-01

    We investigated concentrations of Zn, Cu, Cd and Pb in the compartments of a soil-plant (Urtica dioica)-snail (Cepaea nemoralis) food chain in four polluted locations in the Biesbosch floodplains, the Netherlands, and two reference locations. Total soil metal concentrations in the polluted locations were 4-20 times higher than those in the reference locations. Positive relationships between the generally low leaf concentrations and the soil concentrations were found for Zn only (r2 = 0.20). Bioaccumulation of Zn, Cu and Cd was observed in the snail tissues. We found positive relationships between the snail and leaf concentrations for all metals (range r2 = 0.19-0.46). The relationships between soil and snail concentrations were also positive, except for Cu (range r2 = 0.15-0.33). These results suggest transfer of metals to C. nemoralis snails from U. dioica leaves and from the soil. Metal transfer from polluted leaves to C. nemoralis is more important than transfer from the soil. PMID:16005127

  7. PARP inhibitor ABT-888 affects response of MDA-MB-231 cells to doxorubicin treatment, targeting Snail expression

    PubMed Central

    Mariano, Germano; Ricciardi, Maria Rosaria; Trisciuoglio, Daniela; Zampieri, Michele; Ciccarone, Fabio; Guastafierro, Tiziana; Calabrese, Roberta; Valentini, Elisabetta; Tafuri, Agostino; Del Bufalo, Donatella; Caiafa, Paola; Reale, Anna

    2015-01-01

    To overcome cancer cells resistance to pharmacological therapy, the development of new therapeutic approaches becomes urgent. For this purpose, the use of poly(ADP-ribose) polymerase (PARP) inhibitors in combination with other cytotoxic agents could represent an efficacious strategy. Poly(ADP-ribosyl)ation (PARylation) is a post-translational modification that plays a well characterized role in the cellular decisions of life and death. Recent findings indicate that PARP-1 may control the expression of Snail, the master gene of epithelial-mesenchymal transition (EMT). Snail is highly represented in different resistant tumors, functioning as a factor regulating anti-apoptotic programmes. MDA-MB-231 is a Snail-expressing metastatic breast cancer cell line, which exhibits chemoresistance properties when treated with damaging agents. In this study, we show that the PARP inhibitor ABT-888 was capable to modulate the MDA-MB-231 cell response to doxorubicin, leading to an increase in the rate of apoptosis. Our further results indicate that PARP-1 controlled Snail expression at transcriptional level in cells exposed to doxorubicin. Given the increasing interest in the employment of PARP inhibitors as chemotherapeutic adjuvants, our in vitro results suggest that one of the mechanisms through which PARP inhibition can chemosensitize cancer cells in vivo, is targeting Snail expression thus promoting apoptosis. PMID:25938539

  8. Loss of Scribble Promotes Snail Translation through Translocation of HuR and Enhances Cancer Drug Resistance.

    PubMed

    Zhou, Yi; Chang, Renxu; Ji, Weiwei; Wang, Na; Qi, Meiyan; Xu, Yi; Guo, Jingyu; Zhan, Lixing

    2016-01-01

    Drug resistance of cancer cells to various therapeutic agents and molecular targets is a major problem facing current cancer research. The tumor suppressor gene Scribble encodes a polarity protein that is conserved between Drosophila and mammals; loss of the locus disrupts cell polarity, inhibits apoptosis, and mediates cancer process. However, the role of Scribble in drug resistance remains unknown. We show here that knockdown of Scribble enhances drug resistance by permitting accumulation of Snail, which functions as a transcription factor during the epithelial-mesenchymal transition. Then, loss of Scribble activates the mRNA-binding protein human antigen R (HuR) by facilitating translocation of HuR from the nucleus to the cytoplasm. Furthermore, we demonstrate HuR can recognize AU-rich elements of the Snail-encoding mRNA, thereby regulating Snail translation. Moreover, loss of Scribble-induced HuR translocation mediates the accumulation of Snail via activation of the p38 MAPK pathway. Thus, this work clarifies the role of polarity protein Scribble, which is directly implicated in the regulation of developmental transcription factor Snail, and suggesting a mechanism for Scribble mediating cancer drug resistance. PMID:26527679

  9. Reduced transmission of human schistosomiasis after restoration of a native river prawn that preys on the snail intermediate host

    USGS Publications Warehouse

    Sokolow, Susanne H.; Huttinger, Elizabeth; Jouanard, Nicolas; Hsieh, Michael H.; Lafferty, Kevin D.; Kuris, Armand M.; Riveau, Gilles; Senghor, Simon; Thiam, Cheikh; D'Diaye, Alassane; Faye, Djibril Sarr; De Leo, Giulio A.

    2015-01-01

    Eliminating human parasitic disease often requires interrupting complex transmission pathways. Even when drugs to treat people are available, disease control can be difficult if the parasite can persist in nonhuman hosts. Here, we show that restoration of a natural predator of a parasite’s intermediate hosts may enhance drug-based schistosomiasis control. Our study site was the Senegal River Basin, where villagers suffered a massive outbreak and persistent epidemic after the 1986 completion of the Diama Dam. The dam blocked the annual migration of native river prawns (Macrobrachium vollenhoveni) that are voracious predators of the snail intermediate hosts for schistosomiasis. We tested schistosomiasis control by reintroduced river prawns in a before-after-control-impact field experiment that tracked parasitism in snails and people at two matched villages after prawns were stocked at one village’s river access point. The abundance of infected snails was 80% lower at that village, presumably because prawn predation reduced the abundance and average life span of latently infected snails. As expected from a reduction in infected snails, human schistosomiasis prevalence was 18 ± 5% lower and egg burden was 50 ± 8% lower at the prawn-stocking village compared with the control village. In a mathematical model of the system, stocking prawns, coupled with infrequent mass drug treatment, eliminates schistosomiasis from high-transmission sites. We conclude that restoring river prawns could be a novel contribution to controlling, or eliminating, schistosomiasis.                            

  10. Reduced transmission of human schistosomiasis after restoration of a native river prawn that preys on the snail intermediate host.

    PubMed

    Sokolow, Susanne H; Huttinger, Elizabeth; Jouanard, Nicolas; Hsieh, Michael H; Lafferty, Kevin D; Kuris, Armand M; Riveau, Gilles; Senghor, Simon; Thiam, Cheikh; N'Diaye, Alassane; Faye, Djibril Sarr; De Leo, Giulio A

    2015-08-01

    Eliminating human parasitic disease often requires interrupting complex transmission pathways. Even when drugs to treat people are available, disease control can be difficult if the parasite can persist in nonhuman hosts. Here, we show that restoration of a natural predator of a parasite's intermediate hosts may enhance drug-based schistosomiasis control. Our study site was the Senegal River Basin, where villagers suffered a massive outbreak and persistent epidemic after the 1986 completion of the Diama Dam. The dam blocked the annual migration of native river prawns (Macrobrachium vollenhoveni) that are voracious predators of the snail intermediate hosts for schistosomiasis. We tested schistosomiasis control by reintroduced river prawns in a before-after-control-impact field experiment that tracked parasitism in snails and people at two matched villages after prawns were stocked at one village's river access point. The abundance of infected snails was 80% lower at that village, presumably because prawn predation reduced the abundance and average life span of latently infected snails. As expected from a reduction in infected snails, human schistosomiasis prevalence was 18 ± 5% lower and egg burden was 50 ± 8% lower at the prawn-stocking village compared with the control village. In a mathematical model of the system, stocking prawns, coupled with infrequent mass drug treatment, eliminates schistosomiasis from high-transmission sites. We conclude that restoring river prawns could be a novel contribution to controlling, or eliminating, schistosomiasis. PMID:26195752

  11. Internal distribution of Cd in lettuce and resulting effects on Cd trophic transfer to the snail: Achatina fulica.

    PubMed

    Li, Cheng-Cheng; Dang, Fei; Cang, Long; Zhou, Dong-Mei; Peijnenburg, Willie J G M

    2015-09-01

    The mechanisms underlying Cd trophic transfer along the soil-lettuce-snail food chain were investigated. The fate of Cd within cells, revealed by assessment of Cd chemical forms and of subcellular partitioning, differed between the two examined lettuce species that we examined (L. longifolia and L. crispa). The species-specific internal Cd fate not only influenced Cd burdens in lettuce, with higher Cd levels in L. crispa, but also affected Cd transfer efficiency to the consumer snail (Achatina fulica). Especially, the incorporation of Cd chemical forms (Cd in the inorganic, water-soluble and pectates and protein-integrated forms) in lettuce could best explain Cd trophic transfer, when compared to dietary Cd levels alone and/or subcellular Cd partitioning. Trophically available metal on the subcellular partitioning base failed to shed light on Cd transfer in this study. After 28-d of exposure, most Cd was trapped in the viscera of Achatina fulica, and cadmium bio-magnification was noted in the snails, as the transfer factor of lettuce-to-snail soft tissue was larger than one. This study provides a first step to apply a chemical speciation approach to dictate the trophic bioavailability of Cd through the soil-plant-snail system, which might be an important pre-requisite for mechanistic understanding of metal trophic transfer. PMID:25930053

  12. J. Zool., Lond. (2005) 267, 329338 C 2005 The Zoological Society of London Printed in the United Kingdom doi:10.1017/S0952836905007648 Sex and darts in slugs and snails (Mollusca: Gastropoda

    E-print Network

    Davison, Angus

    2005-01-01

    Kingdom doi:10.1017/S0952836905007648 Sex and darts in slugs and snails (Mollusca: Gastropoda stages of an elaborate courtship, many slugs and snails shoot calcareous `love' darts into each other) of land snails and slugs was recorded, and compared against dart use across the whole

  13. Laboratory Studies of the Effects of Static and Variable Magnetic Fields on Freshwater Fish

    SciTech Connect

    Cada, Glenn F; Bevelhimer, Mark S; Fortner, Allison M; Riemer, Kristina P; Schweizer, Peter E

    2012-04-01

    There is considerable interest in the development of marine and hydrokinetic energy projects in rivers, estuaries, and coastal ocean waters of the United States. Hydrokinetic (HK) technologies convert the energy of moving water in river or tidal currents into electricity, without the impacts of dams and impoundments associated with conventional hydropower or the extraction and combustion of fossil fuels. The Federal Energy Regulatory Commission (FERC) maintains a database that displays the geographical distribution of proposed HK projects in inland and tidal waters (FERC 2012). As of March 2012, 77 preliminary permits had been issued to private developers to study HK projects in inland waters, the development of which would total over 8,000 MW. Most of these projects are proposed for the lower Mississippi River. In addition, the issuance of another 27 preliminary permits for HK projects in inland waters, and 3 preliminary permits for HK tidal projects (totaling over 3,100 MW) were under consideration by FERC. Although numerous HK designs are under development (see DOE 2009 for a description of the technologies and their potential environmental effects), the most commonly proposed projects entail arrays of rotating devices, much like submerged wind turbines, that are positioned in the high-velocity (high energy) river channels. The many diverse HK designs imply a diversity of environmental impacts, but a potential impact common to most is the effect on aquatic organisms of electromagnetic fields (EMF) created by the projects. The submerged electrical generator will emit an EMF into the surrounding water, as will underwater cables used to transmit electricity from the generator to the shore, between individual units in an array (inter-turbine cables), and between the array and a submerged step-up transformer. The electric current moving through these cables will induce magnetic fields in the immediate vicinity, which may affect the behavior or viability of fish and benthic invertebrates (Gill et al. 2005, 2009). It is known that numerous marine and freshwater organisms are sensitive to electrical and magnetic fields, often depending on them for such diverse activities as prey location and navigation (DOE 2009; Normandeau et al. 2011). Despite the wide range of aquatic organisms that are sensitive to EMF and the increasing numbers of underwater electrical transmitting cables being installed in rivers and coastal waters, little information is available to assess whether animals will be attracted, repelled, or unaffected by these new sources of EMF. This knowledge gap is especially significant for freshwater systems, where electrosensitive organisms such as paddlefish and sturgeon may interact with electrical transmission cables. We carried out a series of laboratory experiments to test the sensitivity of freshwater fish and invertebrates to the levels of EMF that are expected to be produced by HK projects in rivers. In this context, EM fields are likely to be emitted primarily by generators in the water column and by transmission cables on or buried in the substrate. The HK units will be located in areas of high-velocity waters that are used as only temporary habitats for most riverine species, so long-term exposure of fish and benthic invertebrates to EMF is unlikely. Rather, most aquatic organisms will be briefly exposed to the fields as they drift downstream or migrate upstream. Because the exposure of most aquatic organisms to EMF in a river would be relatively brief and non-lethal, we focused our investigations on detecting behavioral effects. For example, attraction to the EM fields could result in prolonged exposures to the fields or the HK rotor. On the other hand, avoidance reactions might hinder upstream migrations of fish. The experiments reported here are a continuation of studies begun in FY 2010, which focused on the potential effects of static magnetic fields on snails, clams, and fathead minnows (Cada et al. 2011). Those experiments found little indication that the behaviors of these freshwater species were a

  14. Ecological stoichiometry in freshwater benthic ecosystems: an introduction

    E-print Network

    Benstead, Jon

    and their control from crayfish and snails, a paper addressing the stoichiometric effects on fish and plankton invertebrates, an analysis of the algal content of and its effects on C : P stoichiometry of periphyton, two springs, an examination of the stoichiometric effects on stream periphyton and macroinvertebrates

  15. ORIGINAL PAPER A Late Jurassic freshwater shark assemblage

    E-print Network

    Schöne, Bernd R.

    isotopes Introduction Hybodontiformes are the extinct sister group to all living sharks, skates, and raysORIGINAL PAPER A Late Jurassic freshwater shark assemblage (Chondrichthyes, Hybodontiformes) from

  16. 76 FR 17962 - Strengthening the Scientific Understanding of Climate Change Impacts on Freshwater Resources of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-31

    ...the Scientific Understanding of Climate Change Impacts on Freshwater Resources...the Scientific Understanding of Climate Change Impacts on Freshwater Resources...to freshwater resource data and climate change and identifies next steps to...

  17. Impact of acid and trace metals deposition on freshwater invertebrates in north-eastern Fennoscandia and Kola Peninsula

    SciTech Connect

    Yakovlev, V.

    1996-12-31

    Freshwater invertebrate communities in a total 400 lakes and streams in northeastern Norway, Finnish Lapland and the Kola Peninsula, subjected to the atmospheric deposition were studied. The severe influence of toxic heavy metals, dusts from smelters and mineral enrichment factories were found in the Kola Peninsula. The negative acidification effects on benthic communities were found in the Jarfjord (Norway), Enontekio, Ranua-Posio and Kittila-Kolari (Finnish Lapland) areas and in the Kola Peninsula (Russia). Taxa groups, known to be sensitive to acidification, such as gammarids, snails, mayflies, stone flies, were represented with few species and in a low abundance. Heavy metals accumulation in biota is recorded in areas surrounding nickel smelters in the Kola Peninsula. The metal concentration invertebrates in remote areas is rather wide and depend on an air deposition, characteristics of lake catchment areas, as well as water acidity. The environmental variables, such as lake hydrological type, altitude of lakes, dominant substratum type, abundance of macrophytes and mosses in sampling area, content of pollutants in water also show significant relationships with metal concentration in invertebrates. The most severe negative effects on biota were found in waters with low pH and simultaneously contaminated by heavy metals. The biological method for estimation of simultaneously water acidification and contamination is suggested.

  18. Bioaccumulation and toxicity of CuO nanoparticles by a freshwater invertebrate after waterborne and dietborne exposures

    USGS Publications Warehouse

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

    2014-01-01

    The incidental ingestion of engineered nanoparticles (NPs) can be an important route of uptake for aquatic organisms. Yet, knowledge of dietary bioavailability and toxicity of NPs is scarce. Here we used isotopically modified copper oxide (65CuO) NPs to characterize the processes governing their bioaccumulation in a freshwater snail after waterborne and dietborne exposures. Lymnaea stagnalis efficiently accumulated 65Cu after aqueous and dietary exposures to 65CuO NPs. Cu assimilation efficiency and feeding rates averaged 83% and 0.61 g g–1 d–1 at low exposure concentrations (–1), and declined by nearly 50% above this concentration. We estimated that 80–90% of the bioaccumulated 65Cu concentration in L. stagnalis originated from the 65CuO NPs, suggesting that dissolution had a negligible influence on Cu uptake from the NPs under our experimental conditions. The physiological loss of 65Cu incorporated into tissues after exposures to 65CuO NPs was rapid over the first days of depuration and not detectable thereafter. As a result, large Cu body concentrations are expected in L. stagnalis after exposure to CuO NPs. To the degree that there is a link between bioaccumulation and toxicity, dietborne exposures to CuO NPs are likely to elicit adverse effects more readily than waterborne exposures.

  19. Comparing the efficacy of morphologic and DNA-based taxonomy in the freshwater gastropod genus Radix (Basommatophora, Pulmonata)

    PubMed Central

    Pfenninger, Markus; Cordellier, Mathilde; Streit, Bruno

    2006-01-01

    Background Reliable taxonomic identification at the species level is the basis for many biological disciplines. In order to distinguish species, it is necessary that taxonomic characters allow for the separation of individuals into recognisable, homogeneous groups that differ from other such groups in a consistent way. We compared here the suitability and efficacy of traditionally used shell morphology and DNA-based methods to distinguish among species of the freshwater snail genus Radix (Basommatophora, Pulmonata). Results Morphometric analysis showed that shell shape was unsuitable to define homogeneous, recognisable entities, because the variation was continuous. On the other hand, the Molecularly defined Operational Taxonomic Units (MOTU), inferred from mitochondrial COI sequence variation, proved to be congruent with biological species, inferred from geographic distribution patterns, congruence with nuclear markers and crossing experiments. Moreover, it could be shown that the phenotypically plastic shell variation is mostly determined by the environmental conditions experienced. Conclusion Contrary to DNA-taxonomy, shell morphology was not suitable for delimiting and recognising species in Radix. As the situation encountered here seems to be widespread in invertebrates, we propose DNA-taxonomy as a reliable, comparable, and objective means for species identification in biological research. PMID:17123437

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

    SciTech Connect

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

    2008-08-20

    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.

  1. Three Gorges Dam: Impact of Water Level Changes on the Density of Schistosome-Transmitting Snail Oncomelania hupensis in Dongting Lake Area, China

    PubMed Central

    Wu, Jin-Yi; Zhou, Yi-Biao; Chen, Yue; Liang, Song; Li, Lin-Han; Zheng, Sheng-Bang; Zhu, Shao-ping; Ren, Guang-Hui; Song, Xiu-Xia; Jiang, Qing-Wu

    2015-01-01

    Background Schistosomiasis remains an important public health issue in China and worldwide. Oncomelania hupensis is the unique intermediate host of schistosoma japonicum, and its change influences the distribution of S. japonica. The Three Gorges Dam (TGD) has substantially changed the ecology and environment in the Dongting Lake region. This study investigated the impact of water level and elevation on the survival and habitat of the snails. Methods Data were collected for 16 bottomlands around 4 hydrological stations, which included water, density of living snails (form the Anxiang Station for Schistosomiasis Control) and elevation (from Google Earth). Based on the elevation, sixteen bottomlands were divided into 3 groups. ARIMA models were built to predict the density of living snails in different elevation areas. Results Before closure of TGD, 7 out of 9 years had a water level beyond the warning level at least once at Anxiang hydrological station, compared with only 3 out of 10 years after closure of TGD. There were two severe droughts that happened in 2006 and 2011, with much fewer number of flooding per year compared with other study years. Overall, there was a correlation between water level changing and density of living snails variation in all the elevations areas. The density of living snails in all elevations areas was decreasing after the TGD was built. The relationship between number of flooding per year and the density of living snails was more pronounced in the medium and high elevation areas; the density of living snails kept decreasing from 2003 to 2014. In low elevation area however, the density of living snails decreased after 2003 first and turned to increase after 2011. Our ARIMA prediction models indicated that the snails would not disappear in the Dongting Lake region in the next 7 years. In the low elevation area, the density of living snails would increase slightly, and then stabilize after the year 2017. In the medium elevation region, the change of the density of living snails would be more obvious and would increase till the year 2020. In the high elevation area, the density of living snails would remain stable after the year 2015. Conclusion The TGD influenced water levels and reduced the risk of flooding and the density of living snails in the study region. Based on our prediction models, the density of living snails in all elevations tends to be stabilized. Control of S. japonica would continue to be an important task in the study area in the coming decade. PMID:26114956

  2. Spatio-Temporal Patterns of Schistosomiasis Japonica in Lake and Marshland Areas in China: The Effect of Snail Habitats

    PubMed Central

    Hu, Yi; Gao, Jie; Chi, Meina; Luo, Can; Lynn, Henry; Sun, Liqian; Tao, Bo; Wang, Decheng; Zhang, Zhijie; Jiang, Qingwu

    2014-01-01

    The progress of the integrated control policy for schistosomiasis implemented since 2005 in China, which is aiming at reducing the roles of bovines and humans as infection sources, may be challenged by persistent presence of infected snails in lake and marshland areas. Based on annual parasitologic data for schistosomiasis during 2004–2011 in Xingzi County, a spatio-temporal kriging model was used to investigate the spatio-temporal pattern of schistosomiasis risk. Results showed that environmental factors related to snail habitats can explain the spatio-temporal variation of schistosomiasis. Predictive maps of schistosomiasis risk illustrated that clusters of the disease fluctuated during 2004–2008; there was an extensive outbreak in 2008 and attenuated disease occurrences afterwards. An area with an annually constant cluster of schistosomiasis was identified. Our study suggests that targeting snail habitats located within high-risk areas for schistosomiasis would be an economic and sustainable way of schistosomiasis control in the future. PMID:24980498

  3. Burst firing of action potentials in central snail neurons elicited by d-amphetamine: effect of anticonvulsants.

    PubMed

    Chen, Y H; Chang, C H; Liang, G J; Huang, S S; Hsieh, H M; Teng, C M; Tsai, M C

    2000-09-01

    The effect of anticonvulsants on the burst firing of action potentials in snail central neuron elicited by d-amphetamine was studied in the identified RP4 neuron of the African snail, Achatina fulica Ferussac. Oscillation of membrane potential and burst firing of action potentials were elicited by d-amphetamine in a concentration-dependent manner. Voltage clamped studies revealed that d-amphetamine elicited a negative slope resistance (NSR) in steady-state I-V curve between - 40 and - 10 mV. The burst firing of action potentials was alleviated following extracellular application of phenytoin, but was not affected after ethosuximide, carbamazepine, and valproic acid. The NSR elicited by d-amphetamine was blocked by phenytoin. However, the NSR was not altered if carbamazepine was added. These results suggest that of the four anticonvulsants tested, only phenytoin could alleviate the burst firing of action potentials elicited by d-amphetamine in snail neuron. PMID:11083032

  4. Backbone cyclised peptides from plants show molluscicidal activity against the rice pest Pomacea canaliculata (golden apple snail).

    PubMed

    Plan, Manuel Rey R; Saska, Ivana; Cagauan, Arsenia G; Craik, David J

    2008-07-01

    Golden apple snails ( Pomacea canaliculata) are serious pests of rice in South East Asia. Cyclotides are backbone cyclized peptides produced by plants from Rubiaceae and Violaceae. In this study, we investigated the molluscicidal activity of cyclotides against golden apple snails. Crude cyclotide extracts from both Oldenlandia affinis and Viola odorata plants showed molluscicidal activity comparable to the synthetic molluscicide metaldehyde. Individual cyclotides from each extract demonstrated a range of molluscicidal activities. The cyclotides cycloviolacin O1, kalata B1, and kalata B2 were more toxic to golden apple snails than metaldehyde, while kalata B7 and kalata B8 did not cause significant mortality. The toxicity of the cyclotide kalata B2 on a nontarget species, the Nile tilapia ( Oreochromis niloticus), was three times lower than the common piscicide rotenone. Our findings suggest that the existing diversity of cyclotides in plants could be used to develop natural molluscicides. PMID:18557620

  5. Prospects for monitoring freshwater ecosystems towards the 2010 targets

    PubMed Central

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

    2005-01-01

    Human activities have severely affected the condition of freshwater ecosystems worldwide. Physical alteration, habitat loss, water withdrawal, pollution, overexploitation and the introduction of non-native species all contribute to the decline in freshwater species. Today, freshwater species are, in general, at higher risk of extinction than those in forests, grasslands and coastal ecosystems. For North America alone, the projected extinction rate for freshwater fauna is five times greater than that for terrestrial fauna—a rate comparable to the species loss in tropical rainforest. Because many of these extinctions go unseen, the level of assessment and knowledge of the status and trends of freshwater species are still very poor, with species going extinct before they are even taxonomically classified. Increasing human population growth and achieving the sustainable development targets set forth in 2002 will place even higher demands on the already stressed freshwater ecosystems, unless an integrated approach to managing water for people and ecosystems is implemented by a broad constituency. To inform and implement policies that support an integrated approach to water management, as well as to measure progress in halting the rapid decline in freshwater species, basin-level indicators describing the condition and threats to freshwater ecosystems and species are required. This paper discusses the extent and quality of data available on the number and size of populations of freshwater species, as well as the change in the extent and condition of natural freshwater habitats. The paper presents indicators that can be applied at multiple scales, highlighting the usefulness of using remote sensing and geographical information systems technologies to fill some of the existing information gaps. Finally, the paper includes an analysis of major data gaps and information needs with respect to freshwater species to measure progress towards the 2010 biodiversity targets. PMID:15814353

  6. Seasonal distribution of Vibrio parahaemolyticus in freshwater environs and in association with freshwater fishes in Calcutta.

    PubMed

    Sarkar, B L; Nair, G B; Banerjee, A K; Pal, S C

    1985-01-01

    The seasonal distribution of Vibrio parahaemolyticus in freshwater environs and in association with freshwater fishes was studied in 1982 and 1983. The occurrence of this organism in water and sediments at the three sites studied was very infrequent and was restricted to the summer months, although it was not always isolated during these months. The association of V. parahaemolyticus with plankton was chiefly confined to the summer months and progressively declined with the onset of monsoons, remaining below detectable levels during the postmonsoon and winter months. The incidence and counts of V. parahaemolyticus were consistently higher in association with plankton than with water and sediment samples. V. parahaemolyticus could be recovered throughout the period of investigation from freshly caught and market samples of freshwater fishes. The highest recovery rate of this halophile from fishes was invariably from fecal samples. Most of the strains isolated in this study were untypable, and those which could be typed were predominantly serotypes encountered in the environment. All the isolates were Kanagawa negative. From this study, it could be concluded that the survival of V. parahaemolyticus in freshwater ecosystems is transient and dependent on a biological host. PMID:3977307

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

    PubMed

    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

    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

  8. One, four or 100 genera? A new classification of the cone snails

    PubMed Central

    Puillandre, N.; Duda, T. F.; Meyer, C.; Olivera, B. M.; Bouchet, P.

    2015-01-01

    We present a new classification for the genus Conus sensu lato (family Conidae), based on molecular phylogenetic analyses of 329 species. This classification departs from both the traditional classification in only one genus and from a recently proposed shell- and radula-based classification scheme that separates members of this group into five families and 115 genera. Roughly 140 genus-group names are available for Recent cone snails. We propose to place all cone snails within a single family (Conidae) containing four genera—Conus, Conasprella, Profundiconus and Californiconus (with Conus alone encompassing about 85% of known species)—based on the clear separation of cone snails into four distinct and well-supported groups/lineages in molecular phylogenetic analyses. Within Conus and Conasprella, we recognize 57 and 11 subgenera, respectively, that represent well-supported subgroupings within these genera, which we interpret as evidence of intrageneric distinctiveness. We allocate the 803 Recent species of Conidae listed as valid in the World Register of Marine Species into these four genera and 71 subgenera, with an estimate of the confidence for placement of species in these taxonomic categories based on whether molecular or radula and/or shell data were used in these determinations. Our proposed classification effectively departs from previous schemes by (1) limiting the number of accepted genera, (2) retaining the majority of species within the genus Conus and (3) assigning members of these genera to species groups/subgenera to enable the effective communication of these groups, all of which we hope will encourage acceptance of this scheme. PMID:26300576

  9. Action potential bursts in central snail neurons elicited by d-amphetamine: roles of ionic currents.

    PubMed

    Chen, Y H; Tsai, M C

    2000-01-01

    The roles of the ionic currents in the firing of potential bursts elicited by d-amphetamine in central snail neurons were studied in the identified RP4 neuron of the African snail, Achatina fulica Ferussac, using the two-electrode voltage-clamp method. Oscillations of membrane potential bursts were elicited by d-amphetamine. The action potential bursts elicited by d-amphetamine decreased following intracellular injection of either EDTA or magnesium, or extracellular application of lanthanum. Voltage-clamped studies revealed that d-amphetamine decreased the fast Na(+), Ca(2+) and transient outward K(+) currents of the RP4 neuron. It also decreased the steady-state K(+) current and elicited a negative slope resistance in the steady-state I-V curve between -50 and -10 mV. The amplitude of negative slope resistance was decreased if either Na(+)-free saline or Co(2+)-substituted Ca(2+)-free saline was perfused. d-Amphetamine did not increase the amplitude of the slowly inactivating Ca(2+) current or the persistent Na(+) currents of RP4 neuron. Tetraethylammonium, a blocker of the delayed outward K(+) current, elicited action potential bursts and negative slope resistance in the RP4 neuron, while 4-aminopyridine, an inhibitor of transient outward K(+) current (I(A)), did not. These results demonstrate that the delayed outward K(+) current and the negative slope resistance in steady-state I-V curve elicited by d-amphetamine may be responsible for the action potential bursts in central snail neurons elicited by d-amphetamine. PMID:10683428

  10. Comparative ORESTES-sampling of transcriptomes of immune-challenged Biomphalaria glabrata snails

    PubMed Central

    Hanelt, Ben; Lun, Cheng Man; Adema, Coen M

    2008-01-01

    The snail Biomphalaria glabrata (Gastropoda, Mollusca) is an important intermediate host for the human parasite Schistosoma mansoni (Digenea, Trematoda). Anti-pathogen responses of B. glabrata were studied towards a better understanding of snail immunity and host-parasite compatibility. Open reading frame ESTs (ORESTES) were sampled from different transcriptomes of M line strain B. glabrata, 12 hours post challenge with Escherichia coli (Gram-negative), Micrococcus luteus (Gram-positive) bacteria or compatible S. mansoni, and controls. The resulting 3123 ORESTES represented 2129 unique sequences (373 clusters, 1756 singletons). Of these, 175 (8.1%) were putative defense factors, including lectins, antimicrobial peptides and components of various immune effector systems. Comparison of biological processes (GO-terms) within different transcriptomes indicated that B. glabrata increased oxygen transport and metal binding in reaction to all challenges. Comprehensive comparisons of transcriptomes revealed that responses of B. glabrata against bacteria were similar to each other and differed from the ineffective response to S. mansoni. Furthermore, the response to S. mansoni infection was less comprehensive than that to bacteria. Many novel (unknown) sequences were recovered in association with particular challenges. Biomphalaria glabrata possesses multi-faceted, potent immune defenses. This agrees with the notion that S. mansoni is capable of immune-evasion and prevents effective host defense responses in order to survive in B. glabrata. Future analysis of the numerous unknown sequences recovered from challenged snails may reveal novel immune factors and provide increased understanding of immunity of B. glabrata in relation to parasite-host compatibility. PMID:18590737

  11. Underdispersion and overdispersion of traits in terrestrial snail communities on islands

    PubMed Central

    Astor, Tina; Strengbom, Joachim; Berg, Matty P; Lenoir, Lisette; Marteinsdóttir, Bryndís; Bengtsson, Jan

    2014-01-01

    Understanding and disentangling different processes underlying the assembly and diversity of communities remains a key challenge in ecology. Species can assemble into communities either randomly or due to deterministic processes. Deterministic assembly leads to species being more similar (underdispersed) or more different (overdispersed) in certain traits than would be expected by chance. However, the relative importance of those processes is not well understood for many organisms, including terrestrial invertebrates. Based on knowledge of a broad range of species traits, we tested for the presence of trait underdispersion (indicating dispersal or environmental filtering) and trait overdispersion (indicating niche partitioning) and their relative importance in explaining land snail community composition on lake islands. The analysis of community assembly was performed using a functional diversity index (Rao's quadratic entropy) in combination with a null model approach. Regression analysis with the effect sizes of the assembly tests and environmental variables gave information on the strength of under- and overdispersion along environmental gradients. Additionally, we examined the link between community weighted mean trait values and environmental variables using a CWM-RDA. We found both trait underdispersion and trait overdispersion, but underdispersion (eight traits) was more frequently detected than overdispersion (two traits). Underdispersion was related to four environmental variables (tree cover, habitat diversity, productivity of ground vegetation, and location on an esker ridge). Our results show clear evidence for underdispersion in traits driven by environmental filtering, but no clear evidence for dispersal filtering. We did not find evidence for overdispersion of traits due to diet or body size, but overdispersion in shell shape may indicate niche differentiation between snail species driven by small-scale habitat heterogeneity. The use of species traits enabled us to identify key traits involved in snail community assembly and to detect the simultaneous occurrence of trait underdispersion and overdispersion. PMID:25360251

  12. A bioaccumulation bioassay for freshwater sediments

    USGS Publications Warehouse

    Mac, Michael J.; Noguchi, George E.; Hesselberg, Robert J.; Edsall, Carol C.; Shoesmith, John A.; Bowker, James D.

    1990-01-01

    A laboratory bioassay is described for determining the bioavailability of contaminants from freshwater sediments. The bioassay consists of 10-d exposures to whole sediments under flow-through conditions. After testing five species, the fathead minnow (Pimephales promelas) and the earthworm (Lubricus terrestris) were recommended for use in the test. When the availability of polychlorinated biphenyls (PCBs), Hg and Zn from Great Lakes sediments was examined in laboratory exposures, only the PCBs were accumulated. A field validation study demonstrated that the magnitude of accumulation in laboratory exposures was similar to that in organisms caged in the field. A protocol is recommended for using the test as a standardized bioaccumulation bioassay.

  13. Fish Grubs in Freshwater Ponds and Lakes. 

    E-print Network

    Johnson, Sterling K.

    1981-01-01

    grub. The longevity of the grub stage in fish may be quite extended as observations of more than 4V2 years have been made by some inves tigators. Black Grubs (several species) Black grubs (figure 14) represent several species that affect a....1380 r--- u ----!i -- B-1380 Fish Grubs in Freshwater Ponds and Lakes Sterling K. Johnson* Fish grubs are the immature forms of parasitic worms that invade the flesh of fishes. Grubs appear as round or bead-like structures embedded in the fish...

  14. Conservation of freshwater fishes of Sri Lanka.

    TOXLINE Toxicology Bibliographic Information

    SENANAYAKE FR; MOYLE PB

    HEEP COPYRIGHT: BIOL ABS. Sri Lanka supports a diverse fauna of freshwater fishes, 24% of which are endemic. A survey of the island's streams indicated that a number of the endemic fishes are threatened with extinction and others are depleted due to the interaction of deforestation, urbanization, gem mining, pesticides, exploitation, water diversions and introductions of exotic species. These declines should be halted for ethical, economic and ecological reasons. Methods proposed to reverse the declines include captive breeding, better watershed management, translocation and regulation of fisheries, especially for aquarium fishes. The depauperate Second Peneplain is proposed as a site for translocation of endangered species.

  15. Red-Rimmed Melania (Melanoides tuberculatus) - A Snail in Biscayne National Park, Florida - Harmful Invader or Just a Nuisance?

    USGS Publications Warehouse

    Wingard, G. Lynn; Murray, James B.; Schill, W. Bane; Phillips, Emily C.

    2008-01-01

    Potentially harmful to humans and other animals, the red-rimmed melania snail (Melanoides tuberculatus; family Thiaridae) was discovered in Biscayne National Park, Florida, in 2003 by U.S. Geological Survey (USGS) researchers. The discovery raised concerns for park managers because this aquatic non-native snail is present in significant numbers in areas frequently used by park visitors and poses a risk of exposure. Researchers are addressing questions such as: Is this species a danger to human health? How widespread is it within the park? What factors control the distribution of the species? Is its presence a threat to native animals?

  16. [The macular fatty degeneration of the peripheral retina a variety of the snail track degeneration (author's transl)].

    PubMed

    Daicker, B

    1978-02-22

    A previously undescribed form of snail-track degeneration with scattered flecks was found in three eyes with absolute glaucoma. Light- and electron-microscopic examination of these lesions in the retinal periphery revealed atrophy and gliosis with massive accumulation of fat within the astrocytes and Müller's cells. It was not possible to explain the patchy distribution of the lesions. The fatty change in the macroglia is believed to indicate 'in situ breakdown' of slowly atrophying retina. Morphologic and pathogenetic similarities suggest that all forms of snail-track degeneration with snowflakes represent nonspecific fatty degeneration of the retina. PMID:305729

  17. Taxonomic revision of the Elephant Pupinid snail genus Pollicaria Gould, 1856 (Prosobranchia, Pupinidae)

    PubMed Central

    Kongim, Bangon; Sutcharit, Chirasak; Naggs, Fred; Panha, Somsak

    2013-01-01

    Abstract The status of species currently assigned to the Southeast Asian Elephant Pupinid snail genus Pollicaria Gould, 1856 is reassessed. Shell, radular and reproductive morphology are investigated and analysed with reference to karyotype patterns previously reported and to distribution patterns among the species. Six previously described species are recognised: Pollicaria gravida (Benson, 1856), Pollicaria myersii (Haines, 1855), Pollicaria mouhoti (Pfeiffer, 1862), Pollicaria elephas (Morgan, 1885), Pollicaria crossei (Dautzenberg & d’Hamonville, 1887) and Pollicaria rochebruni (Mabille, 1887). A new subspecies, Pollicaria mouhoti monochroma ssp. n.,is proposed and a dichotomous key to species is provided. PMID:23794846

  18. Unimodal latitudinal pattern of land-snail species richness across northern Eurasian lowlands.

    PubMed

    Horsák, Michal; Chytrý, Milan

    2014-01-01

    Large-scale patterns of species richness and their causes are still poorly understood for most terrestrial invertebrates, although invertebrates can add important insights into the mechanisms that generate regional and global biodiversity patterns. Here we explore the general plausibility of the climate-based "water-energy dynamics" hypothesis using the latitudinal pattern of land-snail species richness across extensive topographically homogeneous lowlands of northern Eurasia. We established a 1480-km long latitudinal transect across the Western Siberian Plain (Russia) from the Russia-Kazakhstan border (54.5°N) to the Arctic Ocean (67.5°N), crossing eight latitudinal vegetation zones: steppe, forest-steppe, subtaiga, southern, middle and northern taiga, forest-tundra, and tundra. We sampled snails in forests and open habitats each half-degree of latitude and used generalized linear models to relate snail species richness to climatic variables and soil calcium content measured in situ. Contrary to the classical prediction of latitudinal biodiversity decrease, we found a striking unimodal pattern of snail species richness peaking in the subtaiga and southern-taiga zones between 57 and 59°N. The main south-to-north interchange of the two principal diversity constraints, i.e. drought stress vs. cold stress, explained most of the variance in the latitudinal diversity pattern. Water balance, calculated as annual precipitation minus potential evapotranspiration, was a single variable that could explain 81.7% of the variance in species richness. Our data suggest that the "water-energy dynamics" hypothesis can apply not only at the global scale but also at subcontinental scales of higher latitudes, as water availability was found to be the primary limiting factor also in this extratropical region with summer-warm and dry climate. A narrow zone with a sharp south-to-north switch in the two main diversity constraints seems to constitute the dominant and general pattern of terrestrial diversity across a large part of northern Eurasia, resulting in a subcontinental diversity hotspot of various taxa in this zone. PMID:25090628

  19. Unimodal Latitudinal Pattern of Land-Snail Species Richness across Northern Eurasian Lowlands

    PubMed Central

    Horsák, Michal; Chytrý, Milan

    2014-01-01

    Large-scale patterns of species richness and their causes are still poorly understood for most terrestrial invertebrates, although invertebrates can add important insights into the mechanisms that generate regional and global biodiversity patterns. Here we explore the general plausibility of the climate-based “water-energy dynamics” hypothesis using the latitudinal pattern of land-snail species richness across extensive topographically homogeneous lowlands of northern Eurasia. We established a 1480-km long latitudinal transect across the Western Siberian Plain (Russia) from the Russia-Kazakhstan border (54.5°N) to the Arctic Ocean (67.5°N), crossing eight latitudinal vegetation zones: steppe, forest-steppe, subtaiga, southern, middle and northern taiga, forest-tundra, and tundra. We sampled snails in forests and open habitats each half-degree of latitude and used generalized linear models to relate snail species richness to climatic variables and soil calcium content measured in situ. Contrary to the classical prediction of latitudinal biodiversity decrease, we found a striking unimodal pattern of snail species richness peaking in the subtaiga and southern-taiga zones between 57 and 59°N. The main south-to-north interchange of the two principal diversity constraints, i.e. drought stress vs. cold stress, explained most of the variance in the latitudinal diversity pattern. Water balance, calculated as annual precipitation minus potential evapotranspiration, was a single variable that could explain 81.7% of the variance in species richness. Our data suggest that the “water-energy dynamics” hypothesis can apply not only at the global scale but also at subcontinental scales of higher latitudes, as water availability was found to be the primary limiting factor also in this extratropical region with summer-warm and dry climate. A narrow zone with a sharp south-to-north switch in the two main diversity constraints seems to constitute the dominant and general pattern of terrestrial diversity across a large part of northern Eurasia, resulting in a subcontinental diversity hotspot of various taxa in this zone. PMID:25090628

  20. Bothrigaster variolaris (Trematoda: Cyclocoelidae) infection in two Florida snail kites (Rostrhamus sociabilis plumbeus)

    USGS Publications Warehouse

    Cole, R.A.; Thomas, N.J.; Roderick, C.L.

    1995-01-01

    Two Florida snail kites (Rostrhamus sociabilis plumbeus, Say) collected in August and December 1993 from Osceola County (28 degrees 15'N, 81 degrees 17'W) and Glades County (26 degrees 45'N, 81 degrees 10'W), Florida (USA), respectively, were infected with Bothrigaster variolaris (Trematoda: Cyclocoelidae); this parasite has not been reported previously from birds in the United States. One bird, a fledgling female, harbored 270 specimens of B. variolaris; the helminths caused airsacculitis and bronchitis, possible contributing factors in the death of this bird. The other bird, a subadult female, was infected with 40 trematodes and had gross and microscopic lesions consistent with trauma as the cause of death.

  1. 40 CFR 35.1605-3 - Publicly owned freshwater lake.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Publicly owned freshwater lake. 35.1605-3 Section 35.1605-3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Cooperative Agreements for Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1605-3...

  2. Freshwater biodiversity conservation: recent progress and future challenges

    E-print Network

    Freshwater biodiversity conservation: recent progress and future challenges David L. Strayer1 Cary of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, Hong Kong, People their marine or terrestrial counterparts. Here, we review progress in conservation of freshwater biodiversity

  3. Young Freshwater Mussels as seen Through a Microscope

    USGS Multimedia Gallery

    During laboratory tests, USGS Upper Midwest Environmental Sciences Center scientists and partners found that the heart and growth rates of some species of young freshwater mussels declined as a result of elevated water temperatures, and many died. Freshwater mussels have been compared to the “...

  4. Freshwater Availability Anomalies and Outbreak of Internal War

    E-print Network

    Columbia University

    Freshwater Availability Anomalies and Outbreak of Internal War: Results from a Global Spatial Time Organizers: Centre for the Study of Civil War, International Peace Research Institute, Oslo (PRIO) & Centre Freshwater Availability Anomalies and Outbreak of Internal War: Results from a Global Spatial Time Series

  5. A subtropical fate awaited freshwater discharged from glacial Lake Agassiz

    SciTech Connect

    Condron, Alan; Winsor, Peter

    2011-02-10

    The 8.2 kyr event is the largest abrupt climatic change recorded in the last 10,000 years, and is widely hypothesized to have been triggered by the release of thousands of kilometers cubed of freshwater into the North Atlantic Ocean. Using a high-resolution (1/6°) global, ocean-ice circulation model we present an alternative view that freshwater discharged from glacial Lake Agassiz would have remained on the continental shelf as a narrow, buoyant, coastal current, and would have been transported south into the subtropical North Atlantic. The pathway we describe is in contrast to the conceptual idea that freshwater from this lake outburst spread over most of the sub-polar North Atlantic, and covered the deep, open-ocean, convection regions. This coastally confined freshwater pathway is consistent with the present-day routing of freshwater from Hudson Bay, as well as paleoceanographic evidence of this event. In this study, using a coarse-resolution (2.6°) version of the same model, we demonstrate that the previously reported spreading of freshwater across the sub-polar North Atlantic results from the inability of numerical models of this resolution to accurately resolve narrow coastal flows, producing instead a diffuse circulation that advects freshwater away from the boundaries. To understand the climatic impact of freshwater released in the past or future (e.g. Greenland and Antarctica), the ocean needs to be modeled at a resolution sufficient to resolve the dynamics of narrow, coastal buoyant flows.

  6. A subtropical fate awaited freshwater discharged from glacial Lake Agassiz

    DOE PAGESBeta

    Condron, Alan; Winsor, Peter

    2011-02-10

    The 8.2 kyr event is the largest abrupt climatic change recorded in the last 10,000 years, and is widely hypothesized to have been triggered by the release of thousands of kilometers cubed of freshwater into the North Atlantic Ocean. Using a high-resolution (1/6°) global, ocean-ice circulation model we present an alternative view that freshwater discharged from glacial Lake Agassiz would have remained on the continental shelf as a narrow, buoyant, coastal current, and would have been transported south into the subtropical North Atlantic. The pathway we describe is in contrast to the conceptual idea that freshwater from this lake outburstmore »spread over most of the sub-polar North Atlantic, and covered the deep, open-ocean, convection regions. This coastally confined freshwater pathway is consistent with the present-day routing of freshwater from Hudson Bay, as well as paleoceanographic evidence of this event. In this study, using a coarse-resolution (2.6°) version of the same model, we demonstrate that the previously reported spreading of freshwater across the sub-polar North Atlantic results from the inability of numerical models of this resolution to accurately resolve narrow coastal flows, producing instead a diffuse circulation that advects freshwater away from the boundaries. To understand the climatic impact of freshwater released in the past or future (e.g. Greenland and Antarctica), the ocean needs to be modeled at a resolution sufficient to resolve the dynamics of narrow, coastal buoyant flows.« less

  7. Circular 54 Freshwater Ornamental Fish Commonly Cultured in

    E-print Network

    Hill, Jeffrey E.

    varieties of freshwater fishes. In 1999 alone, farm-gate value of Florida-raised tropical fish was about US fish groups, while other farms produce a wide spectrum of aquatic livestock. Fish can be groupedCircular 54 Freshwater Ornamental Fish Commonly Cultured in Florida1 Jeffrey E. Hill and Roy P

  8. FRESHWATER FISHES OF ALASKA: THEIR BIOLOGY, DISTRIBUTION AND VALUE

    EPA Science Inventory

    A summary of knowledge of the freshwater fishes of Alaska is provided. Covered are 56 species in 34 genera and 15 families, including strictly freshwater species, anadromous forms and those which normally are marine but which occasionally or regularly enter fresh water. For each ...

  9. Common Freshwater Fish Parasites Pictorial Guide: Crustaceans1

    E-print Network

    Hill, Jeffrey E.

    FA-115 Common Freshwater Fish Parasites Pictorial Guide: Crustaceans1 Deborah B. Pouder, Eric W Guide: Crustaceans The information provided in this guide is not intended to be a complete, detailed Center. #12;2Common Freshwater Fish Parasites Pictorial Guide: Crustaceans https

  10. DNA BARCODING DNA barcoding of Cuban freshwater fishes: evidence for

    E-print Network

    Bernatchez, Louis

    DNA BARCODING DNA barcoding of Cuban freshwater fishes: evidence for cryptic species and taxonomic subunit I) were used to barcode 126 individuals, representing 27 taxonomically recognized species in 17 of the DNA barcodes for cataloguing Cuban freshwater fish species and for identifying those groups

  11. Short communications First record of freshwater fish on the Cape

    E-print Network

    of Africa and consists of ten islands and several islets of volcanic origin (Brown 2004; Fig. 1). Being, Switzerland Received 29 December 2011. Accepted 9 April 2012 The Cape Verdean islands form a distinct aquatic of freshwater bodies on five islands of the archipelago, the first presence of a freshwater fish was recorded

  12. Phospholipase A2 – nexus of aging, oxidative stress, neuronal excitability, and functional decline of the aging nervous system? Insights from a snail model system of neuronal aging and age-associated memory impairment

    PubMed Central

    Hermann, Petra M.; Watson, Shawn N.; Wildering, Willem C.

    2014-01-01

    The aging brain undergoes a range of changes varying from subtle structural and physiological changes causing only minor functional decline under healthy normal aging conditions, to severe cognitive or neurological impairment associated with extensive loss of neurons and circuits due to age-associated neurodegenerative disease conditions. Understanding how biological aging processes affect the brain and how they contribute to the onset and progress of age-associated neurodegenerative diseases is a core research goal in contemporary neuroscience. This review focuses on the idea that changes in intrinsic neuronal electrical excitability associated with (per)oxidation of membrane lipids and activation of phospholipase A2 (PLA2) enzymes are an important mechanism of learning and memory failure under normal aging conditions. Specifically, in the context of this special issue on the biology of cognitive aging we portray the opportunities offered by the identifiable neurons and behaviorally characterized neural circuits of the freshwater snail Lymnaea stagnalis in neuronal aging research and recapitulate recent insights indicating a key role of lipid peroxidation-induced PLA2 as instruments of aging, oxidative stress and inflammation in age-associated neuronal and memory impairment in this model system. The findings are discussed in view of accumulating evidence suggesting involvement of analogous mechanisms in the etiology of age-associated dysfunction and disease of the human and mammalian brain. PMID:25538730

  13. Recent changes in the freshwater composition east of Greenland

    NASA Astrophysics Data System (ADS)

    Steur, L.; Pickart, R. S.; Torres, D. J.; Valdimarsson, H.

    2015-04-01

    Results from three hydrographic surveys across the East Greenland Current between 2011 and 2013 are presented with focus on the freshwater sources. End-member analysis using salinity, ?18O, and nutrient data shows that while meteoric water dominated the freshwater content, a significant amount of Pacific freshwater was present near Denmark Strait with a maximum in August 2013. While in 2011 and 2012 the net sea ice melt was dominated by brine, in 2013 it became close to zero. The amount of Pacific freshwater observed near Denmark Strait in 2013 is as large as the previous maximum in 1998. This, together with the decrease in meteoric water and brine, suggests a larger contribution from the Canadian Basin. We hypothesize that the increase of Pacific freshwater is the result of enhanced flux through Bering Strait and a shorter pathway of Pacific water through the interior Arctic to Fram Strait.

  14. Heart Rate Sensor for Freshwater Mussels

    NASA Astrophysics Data System (ADS)

    Just, C. L.; Vial, D. P.; Kruger, A.; Niemeier, J. J.; Lee, H. W.; Schroer, H. W.

    2014-12-01

    Researchers have long been interested the cardiac activity of mollusks. First, it is important as a basic measure of the animal's metabolism. Further, activities such as feeding and burrowing affect heart rate, as do environmental factors such as water salinity, water temperature, exposure, and predation. We have developed a small, noninvasive sensor for measuring freshwater mussel heart rate. Its working principle is as follows. An infrared (IR) light-emitting diode is placed in contact with the mussel shell. Some of the IR penetrates through the shell, reflects off internal organs, and traverses back. A photodetector detects this IR, and electronics condition the signal. The heartbeat of the animal modulates the IR, allowing one to measure the heart rate. The technique is widely-used in finger heart-rate monitors in humans. The sensors do not have to be positioned above the heart and several locations on the mussel shell work well. The sensor is small (8 mm × 10 mm) and consumes less than 1 mA, and has a simple one-wire interface that allows for easy integration into data acquisition hardware. We present heart rate measurements for the common pocketbook (lampsilis cardium) freshwater mussel.

  15. Reclaiming freshwater sustainability in the Cadillac Desert

    PubMed Central

    Sabo, John L.; Sinha, Tushar; Bowling, Laura C.; Schoups, Gerrit H. W.; Wallender, Wesley W.; Campana, Michael E.; Cherkauer, Keith A.; Fuller, Pam L.; Graf, William L.; Hopmans, Jan W.; Kominoski, John S.; Taylor, Carissa; Trimble, Stanley W.; Webb, Robert H.; Wohl, Ellen E.

    2010-01-01

    Increasing human appropriation of freshwater resources presents a tangible limit to the sustainability of cities, agriculture, and ecosystems in the western United States. Marc Reisner tackles this theme in his 1986 classic Cadillac Desert: The American West and Its Disappearing Water. Reisner's analysis paints a portrait of region-wide hydrologic dysfunction in the western United States, suggesting that the storage capacity of reservoirs will be impaired by sediment infilling, croplands will be rendered infertile by salt, and water scarcity will pit growing desert cities against agribusiness in the face of dwindling water resources. Here we evaluate these claims using the best available data and scientific tools. Our analysis provides strong scientific support for many of Reisner's claims, except the notion that reservoir storage is imminently threatened by sediment. More broadly, we estimate that the equivalent of nearly 76% of streamflow in the Cadillac Desert region is currently appropriated by humans, and this figure could rise to nearly 86% under a doubling of the region's population. Thus, Reisner's incisive journalism led him to the same conclusions as those rendered by copious data, modern scientific tools, and the application of a more genuine scientific method. We close with a prospectus for reclaiming freshwater sustainability in the Cadillac Desert, including a suite of recommendations for reducing region-wide human appropriation of streamflow to a target level of 60%. PMID:21149727

  16. Reclaiming freshwater sustainability in the Cadillac Desert

    USGS Publications Warehouse

    Sabo, John L.; Sinha, Tushar; Bowling, Laura C.; Schoups, Gerrit H.W.; Wallender, Wesley W.; Campana, Michael E.; Cherkauer, Keith A.; Fuller, Pam L.; Graf, William L.; Hopmans, Jan W.; Kominoski, John S.; Taylor, Carissa; Trimble, Stanley W.; Webb, Robert H.; Wohl, Ellen E.

    2010-01-01

    Increasing human appropriation of freshwater resources presents a tangible limit to the sustainability of cities, agriculture, and ecosystems in the western United States. Marc Reisner tackles this theme in his 1986 classic Cadillac Desert: The American West and Its Disappearing Water. Reisner's analysis paints a portrait of region-wide hydrologic dysfunction in the western United States, suggesting that the storage capacity of reservoirs will be impaired by sediment infilling, croplands will be rendered infertile by salt, and water scarcity will pit growing desert cities against agribusiness in the face of dwindling water resources. Here we evaluate these claims using the best available data and scientific tools. Our analysis provides strong scientific support for many of Reisner's claims, except the notion that reservoir storage is imminently threatened by sediment. More broadly, we estimate that the equivalent of nearly 76% of streamflow in the Cadillac Desert region is currently appropriated by humans, and this figure could rise to nearly 86% under a doubling of the region's population. Thus, Reisner's incisive journalism led him to the same conclusions as those rendered by copious data, modern scientific tools, and the application of a more genuine scientific method. We close with a prospectus for reclaiming freshwater sustainability in the Cadillac Desert, including a suite of recommendations for reducing region-wide human appropriation of streamflow to a target level of 60%.

  17. Development of partial life-cycle experiments to assess the effects of endocrine disruptors on the freshwater gastropod Lymnaea stagnalis: a case-study with vinclozolin.

    PubMed

    Ducrot, Virginie; Teixeira-Alves, Mickaël; Lopes, Christelle; Delignette-Muller, Marie-Laure; Charles, Sandrine; Lagadic, Laurent

    2010-10-01

    Long-term effects of endocrine disruptors (EDs) on aquatic invertebrates remain difficult to assess, mainly due to the lack of appropriate sensitive toxicity test methods and relevant data analysis procedures. This study aimed at identifying windows of sensitivity to EDs along the life-cycle of the freshwater snail Lymnaea stagnalis, a candidate species for the development of forthcoming test guidelines. Juveniles, sub-adults, young adults and adults were exposed for 21 days to the fungicide vinclozolin (VZ). Survival, growth, onset of reproduction, fertility and fecundity were monitored weekly. Data were analyzed using standard statistical analysis procedures and mixed-effect models. No deleterious effect on survival and growth occurred in snails exposed to VZ at environmentally relevant concentrations. A significant impairment of the male function occurred in young adults, leading to infertility at concentrations exceeding 0.025 ?g/L. Furthermore, fecundity was impaired in adults exposed to concentrations exceeding 25 ?g/L. Biological responses depended on VZ concentration, exposure duration and on their interaction, leading to complex response patterns. The use of a standard statistical approach to analyze those data led to underestimation of VZ effects on reproduction, whereas effects could reliably be analyzed by mixed-effect models. L. stagnalis may be among the most sensitive invertebrate species to VZ, a 21-day reproduction test allowing the detection of deleterious effects at environmentally relevant concentrations of the fungicide. These results thus reinforce the relevance of L. stagnalis as a good candidate species for the development of guidelines devoted to the risk assessment of EDs. PMID:20623335

  18. Diversity of Conotoxin Gene Superfamilies in the Venomous Snail, Conus victoriae

    PubMed Central

    Robinson, Samuel D.; Safavi-Hemami, Helena; McIntosh, Lachlan D.; Purcell, Anthony W.; Norton, Raymond S.; Papenfuss, Anthony T.

    2014-01-01

    Animal venoms represent a vast library of bioactive peptides and proteins with proven potential, not only as research tools but also as drug leads and therapeutics. This is illustrated clearly by marine cone snails (genus Conus), whose venoms consist of mixtures of hundreds of peptides (conotoxins) with a diverse array of molecular targets, including voltage- and ligand-gated ion channels, G-protein coupled receptors and neurotransmitter transporters. Several conotoxins have found applications as research tools, with some being used or developed as therapeutics. The primary objective of this study was the large-scale discovery of conotoxin sequences from the venom gland of an Australian cone snail species, Conus victoriae. Using cDNA library normalization, high-throughput 454 sequencing, de novo transcriptome assembly and annotation with BLASTX and profile hidden Markov models, we discovered over 100 unique conotoxin sequences from 20 gene superfamilies, the highest diversity of conotoxins so far reported in a single study. Many of the sequences identified are new members of known conotoxin superfamilies, some help to redefine these superfamilies and others represent altogether new classes of conotoxins. In addition, we have demonstrated an efficient combination of methods to mine an animal venom gland and generate a library of sequences encoding bioactive peptides. PMID:24505301

  19. Genetic variation in a Pacific Island land snail: population history versus current drift and selection.

    PubMed Central

    Goodacre, S L

    2001-01-01

    Previous studies of Partula land snails from the Society Islands, French Polynesia, have shown that there can be striking differences in shell shape, colour and banding pattern between nearby populations, even in the absence of any obvious geographical barriers to the movement of snails, or environmental gradients. Elsewhere, there may be relative uniformity over large distances. Analysis of a mitochondrial gene from Partula taeniata (Mörch) shows a similar pattern. The relative frequencies of two mitochondrial haplotypes change abruptly over small distances, seemingly independent of the environment. Although the transition roughly coincides with clines in the frequencies of some morphological characteristics, it appears to be unrelated to others. It is likely that many of the differences accumulated while populations were isolated from one another, through the effects of random genetic drift and selection. Isolation of populations may have occurred as a result of demographic changes, or during the process of colonization if occasional long-distance migrants establish populations ahead of the main invading front. Current genetic drift, even without restrictions to gene flow, may contribute to genetic patchiness on a small scale, although it is likely that conspicuous characteristics such as shell colours and banding patterns are also influenced by selection. PMID:11209880

  20. Sensitivity of isolated eggs of pond snails: a new method for toxicity assays and risk assessment.

    PubMed

    Liu, Tengteng; Koene, Joris M; Dong, Xiaoxiao; Fu, Rongshu

    2013-05-01

    The concentration of heavy metals in the environment is normally low. We here address whether using the development of isolated pond snail Radix auricularia eggs would provide a more sensitive endpoint and whether the gelatinous matrix of the egg mass surrounding the eggs indeed protects the snail embryos. In the present study, artificial removal of the gelatinous matrix of egg masses greatly increased the sensitivity of developing eggs to a heavy metal (cadmium). The sensitivity of isolated eggs to cadmium was determined using several convenient endpoints, including mortality, hatching rate, and heart rate, with an acute toxicity test and a subchronic test. In the acute toxicity test, a 96-h LC(50) value of 58.26 ?g/L cadmium was determined. In the subchronic toxicity test, sublethal effects in terms of a significant reduction in hatching rate could be found in the 25-?g/L treatment, and a significant decrease of heart rate was observed in both treatments (5 and 25 ?g/L). The high sensitivity of isolated eggs indicates that such tests can be efficient for toxicity assays and risk assessment, although one needs to keep in mind that the ecologically relevant measure of toxicity will be how eggs are affected when they are still inside the egg mass. PMID:22965948

  1. Evaluation of the genotoxic potential of soil contaminated with mineral coal tailings on snail Helix aspersa.

    PubMed

    de Souza, Melissa Rosa; da Silva, Fernanda Rabaioli; de Souza, Claudia Telles; Niekraszewicz, Liana; Dias, Johnny Ferraz; Premoli, Suziane; Corrêa, Dione Silva; Soares, Mariana do Couto; Marroni, Norma Possa; Morgam-Martins, Maria Isabel; da Silva, Juliana

    2015-11-01

    Coal remains an important source of energy, although the fuel is a greater environmental pollutant. Coal is a mixture of several chemicals, especially inorganic elements and polycyclic aromatic hydrocarbons (PAH). Many of these compounds have mutagenic and carcinogenic effects on organisms exposed to this mineral. In the town of Charqueadas (Brazil), the tailings from mining were used for landfill in the lower areas of the town, and the consequence is the formation of large deposits of this material. The purpose of this study was to evaluate the genotoxic potential of soil samples contaminated by coal waste in different sites at Charqueadas, using the land snail Helix aspersa as a biomonitor organism. Thirty terrestrial snails were exposed to different treatments: 20 were exposed to the soil from two different sites in Charqueadas (site 1 and 2; 10 in each group) and 10 non-exposed (control group). Hemolymph cells were collected after 24h, 5days and 7days of exposure and comet assay, micronucleus test, oxidative stress tests were performed. Furthermore, this study quantified the inorganic elements present in soil samples by the PIXE technique and polycyclic aromatic hydrocarbons (PAH) by HPLC. This evaluation shows that, in general, soils from sites in Charqueadas, demonstrated a genotoxic effect associated with increased oxidative stress, inorganic and PAH content. These results demonstrate that the coal pyrite tailings from Charqueadas are potentially genotoxic and that H. aspersa is confirmed to be a sensitive instrument for risk assessment of environmental pollution. PMID:26295689

  2. Observations on bilharziasis and the potential snail hosts in the Republic of the Congo (Brazzaville)

    PubMed Central

    McCullough, Fergus S.

    1964-01-01

    In 1962, the author conducted a preliminary investigation of bilharziasis in the Republic of the Congo (Brazzaville), at the request of the Government, in order to review existing information and work done on bilharziasis, to assess the prevalence and distribution of the disease, to make observations on the potential snail hosts, and to propose further suitable studies and control measures. Although little time was available for this study, it appears reasonable to conclude that Schistosoma haematobium is confined to a few foci in the west of the country, the main snail host being a new subspecies of Bulinus (B.) truncatus. Intestinal bilharziasis is apparently very rare, but systematic stool surveys have not been done; S. mansoni may be, or become, endemic at Dolisie, where Biomphalaria camerunensis is abundant. The main factors governing the restricted distribution of bilharziasis are discussed. Bilharziasis control appears to merit relatively low priority compared with that due to several other diseases, and the author concludes that bilharziasis is unlikely to become widespread in future years unless there is major environmental change, although the intensity of transmission may increase in some present endemic foci. PMID:14163961

  3. Histopathological changes in snail, Pomacea canaliculata, exposed to sub-lethal copper sulfate concentrations.

    PubMed

    Dummee, Vipawee; Tanhan, Phanwimol; Kruatrachue, Maleeya; Damrongphol, Praneet; Pokethitiyook, Prayad

    2015-12-01

    The acute toxicity test of Cu including range-finding and definitive test, was performed on golden apple snails, Pomacea canaliculata. The median lethal concentrations (LC50) of Cu at exposure times of 24, 48, 72 and 96h were 330, 223, 177 and 146µg/L, respectively. P. canaliculata were exposed to Cu at 146µg/L for 96h to study bioaccumulation and histopathological alterations in various organs. Snails accumulated elevated levels of Cu in gill, and lesser amounts in the digestive tract, muscle, and digestive gland. Histopathological investigation revealed several alterations in the epithelia of gill, digestive tract (esophagus, intestine, rectum), and digestive gland. The most striking changes were observed in the epithelium of the gill in which there was loss of cilia, an increase in number of mucus cells, and degeneration of columnar cells. Similar changes occurred in digestive tract epithelium. The digestive gland showed moderate alterations, vacuolization and degeneration of cells and an increase in the number of basophilic cells. We concluded that, P. canaliculata has a great potential as a bioindicator for Cu, and a biomarker for monitoring Cu contamination in aquatic environment. PMID:26295753

  4. An optimized DNA extraction and multiplex PCR for the detection of Fasciola sp. in lymnaeid snails.

    PubMed

    Caron, Y; Righi, S; Lempereur, L; Saegerman, C; Losson, B

    2011-05-31

    This study deals with the development and validation of an original PCR protocol to assess the presence of Fasciola hepatica in Galba truncatula its main intermediate host in Western Europe. In the present study two DNA extraction techniques are compared and a new multiplex PCR is described. The Chelex(®) DNA extraction technique showed to be more appropriate than the classical Phenol/Chloroform/Proteinase K based method because of the absence of toxic organic solvent, shorter duration and lower cost, and a higher reproducibility regarding DNA concentrations and wavelength ratios. The multiplex PCR was set up to amplify the lymnaeid internal transcribed spacer 2 sequence (500-600 bp) that act as an internal control and a 124 bp Fasciola sp. sequence that is repeated more than 300,000 times in fluke whole genome. Ninety six snails were pooled and 6 snails (6.25%) found positive for Fasciola sp. The limit of detection is lower than the minimal biological infestation unit (one miracidium). DNA extracts from Paramphistomum daubneyi, Dicrocoelium lanceolatum, and Fascioloides magna did not cross react. PMID:21242033

  5. Host diversity begets parasite diversity: Bird final hosts and trematodes in snail intermediate hosts

    USGS Publications Warehouse

    Hechinger, R.F.; Lafferty, K.D.

    2005-01-01

    An unappreciated facet of biodiversity is that rich communities and high abundance may foster parasitism. For parasites that sequentially use different host species throughout complex life cycles, parasite diversity and abundance in 'downstream' hosts should logically increase with the diversity and abundance of 'upstream' hosts (which carry the preceding stages of parasites). Surprisingly, this logical assumption has little empirical support, especially regarding metazoan parasites. Few studies have attempted direct tests of this idea and most have lacked the appropriate scale of investigation. In two different studies, we used time-lapse videography to quantify birds at fine spatial scales, and then related bird communities to larval trematode communities in snail populations sampled at the same small spatial scales. Species richness, species heterogeneity and abundance of final host birds were positively correlated with species richness, species heterogeneity and abundance of trematodes in host snails. Such community-level interactions have rarely been demonstrated and have implications for community theory, epidemiological theory and ecosystem management. ?? 2005 The Royal Society.

  6. [Case report-fatal snail bait (metaldehyde) overdose presenting aspiration pneumonia].

    PubMed

    Kiyota, Kazuya

    2003-10-01

    A-55-year-old man ingested unknown amount of snail poison bait containing metaldehyde. He was mentally retarded and presented pica. On admission, his vital sign was stable, and the extremeties were spastic. Then, gastric lavage was unsuccessful because of massive unbited food. Activated charcoal and cathartic were administrated. On the next day, general convulsion occurred and respiratory distress advanced, so he was intubated. On the 3rd day, infiltration shadow appeared on chest roentogenogram and, his respiration was assisted mechanically. Thereby, acute lung injury advanced regardless of tracheostomy, kinetic therapy, antibiotics and steroid pulse therapy. He died of respiratory failure on the 33rd day. Serum test showed HBs and HBe antigen, CT scan revealed ascites and splenomegaly; the clinical course might be worsened by liver cirrhosis. HPLC revealed metaldehyde in the serum (total 80.6 microg/ml). He ingested 2.7 g of metaldehyde maximally estimated. Although Japan Poison Information Center reported that snail poison bait poisoning is often in dogs in Japan, human poisoning is rare. PMID:14740568

  7. Correlating Molecular Phylogeny with Venom Apparatus Occurrence in Panamic Auger Snails (Terebridae)

    PubMed Central

    Holford, Mandë; Puillandre, Nicolas; Modica, Maria Vittoria; Watkins, Maren; Collin, Rachel; Bermingham, Eldredge; Olivera, Baldomero M.

    2009-01-01

    Central to the discovery of neuroactive compounds produced by predatory marine snails of the superfamily Conoidea (cone snails, terebrids, and turrids) is identifying those species with a venom apparatus. Previous analyses of western Pacific terebrid specimens has shown that some Terebridae groups have secondarily lost their venom apparatus. In order to efficiently characterize terebrid toxins, it is essential to devise a key for identifying which species have a venom apparatus. The findings presented here integrate molecular phylogeny and the evolution of character traits to infer the presence or absence of the venom apparatus in the Terebridae. Using a combined dataset of 156 western and 33 eastern Pacific terebrid samples, a phylogenetic tree was constructed based on analyses of 16S, COI and 12S mitochondrial genes. The 33 eastern Pacific specimens analyzed represent four different species: Acus strigatus, Terebra argyosia, T. ornata, and T. cf. formosa. Anatomical analysis was congruent with molecular characters, confirming that species included in the clade Acus do not have a venom apparatus, while those in the clade Terebra do. Discovery of the association between terebrid molecular phylogeny and the occurrence of a venom apparatus provides a useful tool for effectively identifying the terebrid lineages that may be investigated for novel pharmacological active neurotoxins, enhancing conservation of this important resource, while providing supplementary information towards understanding terebrid evolutionary diversification. PMID:19890382

  8. Adaptive responses and invasion: the role of plasticity and evolution in snail shell morphology

    PubMed Central

    Kistner, Erica J; Dybdahl, Mark F

    2013-01-01

    Invasive species often exhibit either evolved or plastic adaptations in response to spatially varying environmental conditions. We investigated whether evolved or plastic adaptation was driving variation in shell morphology among invasive populations of the New Zealand mud snail (Potamopyrgus antipodarum) in the western United States. We found that invasive populations exhibit considerable shell shape variation and inhabit a variety of flow velocity habitats. We investigated the importance of evolution and plasticity by examining variation in shell morphological traits 1) between the parental and F1 generations for each population and 2) among populations of the first lab generation (F1) in a common garden, full-sib design using Canonical Variate Analyses (CVA). We compared the F1 generation to the parental lineages and found significant differences in overall shell shape indicating a plastic response. However, when examining differences among the F1 populations, we found that they maintained among-population shell shape differences, indicating a genetic response. The F1 generation exhibited a smaller shell morph more suited to the low-flow common garden environment within a single generation. Our results suggest that phenotypic plasticity in conjunction with evolution may be driving variation in shell morphology of this widespread invasive snail. PMID:23467920

  9. Molluscicidal saponins from Sapindus mukorossi, inhibitory agents of golden apple snails, Pomacea canaliculata.

    PubMed

    Huang, Hui-Chi; Liao, Sin-Chung; Chang, Fang-Rong; Kuo, Yao-Haur; Wu, Yang-Chang

    2003-08-13

    Extracts of soapnut, Sapindus mukorossi Gaertn. (Sapindaceae) showed molluscicidal effects against the golden apple snail, Pomacea canaliculata Lamarck. (Ampullariidae) with LC(50) values of 85, 22, and 17 ppm after treating 24, 48, and 72 h, respectively. Bioassay-directed fractionation of S. mukorossi resulted in the isolation of one new hederagenin-based acetylated saponin, hederagenin 3-O-(2,4-O-di-acetyl-alpha-l-arabinopyranoside)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (1), along with six known hederagenin saponins, hederagenin 3-O-(3,4-O-di-acetyl-alpha-l-arabinopyranoside)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (2), hederagenin 3-O-(3-O-acetyl-beta-d-xylopyranosyl)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (3), hederagenin 3-O-(4-O-acetyl-beta-d-xylopyranosyl)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (4), hederagenin 3-O-(3,4-O-di-acetyl-beta-d-xylopyranosyl)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (5), hederagenin 3-O-beta-d-xylopyranosyl-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (6), and hederagenin 3-O-alpha-l-arabinopyranoside (7). The bioassay data revealed that 1-7 were molluscicidal, causing 70-100% mortality at 10 ppm against the golden apple snail. PMID:12903945

  10. The identification and characteristics of Echinoparyphium rubrum (Cort. 1914) new comb. (Trematoda, Echinostomatidae) based on experimental evidence of the life cycle

    USGS Publications Warehouse

    Kanev, I.; Sorensen, R.; Sterner, M.; Cole, R.; Fried, B.

    1998-01-01

    The life cycle of Echinoparyphium rubrum (Cort, 1914) comb. n. has been completed experimentally. All of the developmental stages egg, miracidium, sporocyst, mother and daughter rediae, cercaria, metacercaria, and adult were examined and described. The miracidia infected freshwater snails of the genus Physa , P. gyrina and P. occidentalis. Attempts to infect snails of the genera Lymnaea, L. auricularis, L. peregra, L. truncatula and Bulinus, B. truncatus failed. Cercariae infected various pulmonate and prosobranch freshwater snails, mussels, frogs, water turtles and planarians. The adults developed in the small intestine of birds and mammals. The identity and major characteristics of Echinoparyphium rubrum are discussed. Synonyms of E. rubrum are Cercaria rubra Cort, 1914; Cercaria biflexa Faust, 1917; Cercaria chisolenata Faust, 1918; Echinostoma callawayensis Barker et Noll, 1915; Echinostoma revolutum of Johnson (1920); Echinoparyphium elegans of Cannon (1938), of Bain and Trelfall (1977), of Mahoney and Trelfall (1977); and Echinoparyphium recurvatum of Jilek (1977), Harley (1972), Sankurathri and Holmes (1976). Comparisons are made between E. rubrum and its 43-collar-spined allies: E. flexum from North America, E. cinctum from Europe, E. dunni from Asia and E. elegans from Africa.

  11. Lanthanide concentrations in freshwater plants and molluscs, related to those in surface water, pore water and sediment. A case study in The Netherlands.

    PubMed

    Weltje, Lennart; Heidenreich, Heike; Zhu, Wangzhao; Wolterbeek, Hubert Th; Korhammer, Siegfried; de Goeij, Jeroen J M; Markert, Bernd

    2002-03-01

    Industrial emissions of lanthanides to aquatic ecosystems increase, but knowledge of the environmental fate of these metals is limited. Here we focus attention upon the distribution of lanthanides in freshwater ecosystems, describing lanthanide partitioning between sediment, water and biota. Since lanthanides are often used as oxidation-state analogues for actinides, their distribution can reflect long-term behaviour of the radioactive transuranics. Concentrations of all 14 naturally occurring lanthanides were measured by ICP-MS in Sago pondweed (Potamogeton pectinatus), common duckweed (Lemna minor), seven different mollusc species (tissue and shell), two sediment fractions (< 2 mm and < 63 microm), surface water and sediment pore water from five locations in The Netherlands. In all samples, the typical 'saw-tooth' lanthanide pattern was observed, which implies that lanthanides are transported as a coherent group through aquatic ecosystems. Typical deviations from this pattern were found for Ce and Eu and could be explained by their redox chemistry. The variation in concentrations in abiotic fractions was limited, i.e. within one order of magnitude. However, variations of up to three orders of magnitude were observed in biotic samples, suggesting different affinities among organisms for lanthanides as a group, with significant differences only among molluscs and pondweed samples in relation to sampling location. For P. pectinatus it was shown that pore water was the most important lanthanide source, and for snails, food (plants) seems to be the dominant lanthanide source. Lanthanides were not equally distributed between mollusc shell and tissue and the ratio of lanthanide concentrations in shell and tissue were dependent on the sampling location. Shells contained much lower concentrations and were relatively enriched in Eu, and to a lesser extent in Ce. Bioconcentration factors for lanthanides in plants and snails relative to surface water were typically between 10000 and 100000 l x kg(-1) dry matter, while sediment-water partition coefficients were between 100000 and 3000000 l x kg(-1) dry matter. There was a low extent of biomagnification in the plant-to-snail system, with a maximum biomagnification factor of 5.5. Many distribution coefficients displayed a slight decrease with atomic number. This can be attributed to the general increase in ligand stability constants with atomic number, keeping the heavier lanthanides preferentially in solution. PMID:11887873

  12. Agglutinating Activity and Structural Characterization of Scalarin, the Major Egg Protein of the Snail Pomacea scalaris (d’Orbigny, 1832)

    PubMed Central

    Ituarte, Santiago; Dreon, Marcos Sebastián; Ceolin, Marcelo; Heras, Horacio

    2012-01-01

    Apple snail perivitellins are emerging as ecologically important reproductive proteins. To elucidate if the protective functions of the egg proteins of Pomacea canaliculata (Caenogastropoda, Ampullariidae), involved in embryo defenses, are present in other Pomacea species we studied scalarin (PsSC), the major perivitellin of Pomacea scalaris. Using small angle X-ray scattering, fluorescence and absorption spectroscopy and biochemical methods, we analyzed PsSC structural stability, agglutinating activity, sugar specificity and protease resistance. PsSC aggluttinated rabbit, and, to a lesser extent, human B and A erythrocytes independently of divalent metals Ca2+ and Mg2+ were strongly inhibited by galactosamine and glucosamine. The protein was structurally stable between pH 2.0 to 10.0, though agglutination occurred only between pH 4.0 to 8.0 (maximum activity at pH 7.0). The agglutinating activity was conserved up to 60°C and completely lost above 80°C, in agreement with the structural thermal stability of the protein (up to 60°C). PsSC was able to withstand in vitro gastrointestinal digestion, and showed no trypsin inhibition activity. The presence of lectin activity has been reported in eggs of other Pomacea snails, but here we link for the first time, this activity to an apple snail multifunctional perivitellin. This novel role for a snail egg storage protein is different from closely related P.canaliculata defensive proteins. PMID:23185551

  13. Effect of Climate Change on Invasion Risk of Giant African Snail (Achatina fulica Férussac, 1821: Achatinidae) in India

    PubMed Central

    Rekha Sarma, Roshmi; Munsi, Madhushree; Neelavara Ananthram, Aravind

    2015-01-01

    The Giant African Snail (Achatina fulica) is considered to be one the world’s 100 worst invasive alien species. The snail has an impact on native biodiversity, and on agricultural and horticultural crops. In India, it is known to feed on more than fifty species of native plants and agricultural crops and also outcompetes the native snails. It was introduced into India in 1847 and since then it has spread all across the country. In this paper, we use ecological niche modeling (ENM) to assess the distribution pattern of Giant African Snail (GAS) under different climate change scenarios. The niche modeling results indicate that under the current climate scenario, Eastern India, peninsular India and the Andaman and Nicobar Islands are at high risk of invasion. The three different future climate scenarios show that there is no significant change in the geographical distribution of invasion prone areas. However, certain currently invaded areas will be more prone to invasion in the future. These regions include parts of Bihar, Southern Karnataka, parts of Gujarat and Assam. The Andaman and Nicobar and Lakshadweep Islands are highly vulnerable to invasion under changed climate. The Central Indian region is at low risk due to high temperature and low rainfall. An understanding of the invasion pattern can help in better management of this invasive species and also in formulating policies for its control. PMID:26618637

  14. Optical Recording of Odor-Evoked Responses in the Olfactory Brain of the Naïve and Aversively Trained Terrestrial Snails

    PubMed Central

    Nikitin, Eugeny S.; Balaban, Pavel M.

    2000-01-01

    Regular spontaneous oscillations were recorded both electro- and optophysiologically using a voltage-sensitive absorption dye in the olfactory part of the brain (procerebral lobe of the cerebral ganglia) of the gastropod mollusk Helix lucorum. Odor application caused transient changes in procerebral oscillations, and an odor-evoked potential was recorded in the procerebrum (PC). The wave of evoked potential originated near the place of olfactory nerve entrance into the PC and propagated via the procerebral neuropile toward the cell body layer. The spread of the odor-evoked potential corresponded roughly to the neuropile area, whereas the spontaneous oscillations were recorded in the cell body layer of the PC and were not observed in the neuropile. Evoked potential did not produce additional events intercalated into the ongoing spontaneous oscillations. Changes in parameters of spontaneous oscillations to the repeated presentations of the same odor were variable. To estimate the role of spontaneous oscillations in odor encoding, we trained the snail to avoid cineole, using paired presentations of cineole and electric shock. Elaboration of conditioned aversion to cineole applications resulted in distinct pairing-specific changes in behavior of the snails and procerebral activity. Responses to odor (cineole) applications were not different in amplitude or frequency of spontaneous oscillations in control and trained snails, whereas ratio of amplitudes of the same oscillation wave in proximal and distal regions of the procerebrum was significantly different in control and aversively trained snails, reflecting changes in neural firing in certain areas of the olfactory lobe. PMID:11112801

  15. EFFECTS OF IRRADIATION ON THE REPRODUCTIVE ABILITY OF ZONITOIDES ARBOREUS (SAY), A SNAIL PEST OF ORCHID ROOTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to increased international trade, there has been an increase in the risk of invasion by alien pest species, including pest species of slugs and snails. Irradiation has proven useful as an quarantine treatment for control of insect pests infesting horticultural commodities, and this technology c...