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Sample records for invasive snail pomacea

  1. The major egg reserve protein from the invasive apple snail Pomacea maculata is a complex carotenoprotein related to those of Pomacea canaliculata and Pomacea scalaris.

    PubMed

    Pasquevich, M Y; Dreon, M S; Heras, H

    2014-03-01

    Snails from the genus Pomacea lay conspicuous masses of brightly colored eggs above the water. Coloration is given by carotenoproteins that also which play important roles in protection against sun radiation, stabilizing and transporting antioxidant molecules and helping to protect embryos from desiccation and predators. They seem a key acquisition, but have been little studied. Here we report the characteristics of the major carotenoprotein from Pomacea maculata and the first comparison among these egg proteins. This particle, hereafter PmPV1, represents ~52% of perivitellin fluid protein. It is a glyco-lipo-carotenoprotein responsible for the bright reddish egg coloration. With VHDL characteristics, PmPV1 apparent molecular mass is 294kDa, composed of five non-covalently bound subunits of pI 4.7-9.8 and masses between 26 and 36kDa whose N-terminal sequences were obtained. It is a glyco-lipo-carotenoprotein scarcely lipidated (<1%) but highly glycosilated (13% by wt). Lipids include phospholipids, free fatty acids and carotenoids; mannose and galactose predominate over other monosaccharides. Main carotenoids are esterified and non-esterified astaxanthin (71 and 25%, respectively). Carotenoid removal does not seem to affect the structural characteristics of the oligomer, while deglycosilation reduces subunit number from five to a single one. The carotenoid-protein association protected the former against oxidation. PmPV1 cross reacts with polyclonal antibodies against the PcOvo, the major carotenoprotein from Pomacea canaliculata. The characterization of PmPV1 allows the first comparisons among snail carotenoproteins and further highlights the importance of these perivitellins in the reproductive strategy of Pomacea.

  2. Uric acid deposits and estivation in the invasive apple-snail, Pomacea canaliculata.

    PubMed

    Giraud-Billoud, Maximiliano; Abud, María A; Cueto, Juan A; Vega, Israel A; Castro-Vazquez, Alfredo

    2011-04-01

    The physiological ability to estivate is relevant for the maintenance of population size in the invasive Pomacea canaliculata. However, tissue reoxygenation during arousal from estivation poses the problem of acute oxidative stress. Uric acid is a potent antioxidant in several systems and it is stored in specialized tissues of P. canaliculata. Changes in tissue concentration of thiobarbituric acid reactive substances (TBARS), uric acid and allantoin were measured during estivation and arousal in P. canaliculata. Both TBARS and uric acid increased two-fold during 45 days estivation, probably as a consequence of concomitant oxyradical production during uric acid synthesis by xanthine oxidase. However, after arousal was induced, uric acid and TBARS dropped to or near baseline levels within 20 min and remained low up to 24h after arousal induction, while the urate oxidation product allantoin continuously rose to a maximum at 24h after induction, indicating the participation of uric acid as an antioxidant during reoxygenation. Neither uric acid nor allantoin was detected in the excreta during this 24h period. Urate oxidase activity was also found in organs of active snails, but activity shut down during estivation and only a partial and sustained recovery was observed in the midgut gland.

  3. Physiology of the invasive apple snail Pomacea maculata: tolerance to low temperatures

    USGS Publications Warehouse

    Deaton, Lewis E.; Schmidt, William; Leblanc, Brody; Carter, Jacoby; Mueck, Kristy; Merino, Sergio

    2016-01-01

    Apple snails of the genus Pomacea native to South America have invaded and become established in Europe, Asia, and the United States. Both the channeled apple snail Pomacea canaliculata and the island apple snail Pomacea maculata have been reported in the United States. The two species are difficult to distinguish using morphological characters, leading to uncertainty about the identity of the animals from populations in the United States. Because the snails are subtropical, their tolerance of low temperatures is a critical factor in limiting the spread of the animals from present localities along the coast of the Gulf of Mexico to more northern areas. The tolerance of P. maculata collected in Louisiana to temperatures as low as 0°C was examined. There was no mortality among animals maintained in water at temperatures of 20°C or 15°C for 10 days. Survival of animals during a 10-day exposure to water at temperatures 10°C and 5°C was 50%. The LD50 for a 10-day exposure was 7°C. Snails did not survive more than 5 days in liquid water at 0°C. Ammonia excretion by animals in temperatures of 20°C and 15°C was comparable to values reported for freshwater gastropods; at very low temperatures, excretion of ammonia was decreased. There was no difference in the mean values of the osmolality of the hemolymph of animals exposed to 20°C, 15°C and 10°C for 10 days. Sequencing of mitochondrial cytochrome oxidase 1 identified the animals in the Louisiana population used in this study as P. maculata.

  4. A pilot study testing a natural and a synthetic molluscicide for controlling invasive apple snails (Pomacea maculata)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pomacea maculata (formerly P. insularum), an apple snail native to South America, was discovered in Louisiana in 2008. These snails strip vegetation, reproduce at tremendous rates, and have reduced rice production and caused ecosystem changes in Asia. In this study snails were exposed to two mollusc...

  5. Count Your Eggs Before They Invade: Identifying and Quantifying Egg Clutches of Two Invasive Apple Snail Species (Pomacea)

    PubMed Central

    Kyle, Colin H.; Plantz, Allyson L.; Shelton, Therese; Burks, Romi L.

    2013-01-01

    Winning the war against invasive species requires early detection of invasions. Compared to terrestrial invaders, aquatic species often thrive undetected under water and do not garner notice until too late for early action. However, fortunately for managers, apple snails (Family Ampullariidae, Genus Pomacea) provide their own conspicuous sign of invasion in the form of vibrantly colored egg clutches. Managers can potentially use egg clutches laid in the riparian zone as a means of early detection and species identification. To facilitate such efforts, we quantified differences in characteristics (length, width, depth, mass, egg number) of field-laid clutches for the two most common invasive species of apple snail, P. canaliculata and P. maculata, in native and non-native populations. Pomacea canaliculata native and non-native populations differed noticeably only in width. Native P. maculata clutches possessed significantly greater width, mass and eggs numbers compared with native P. canaliculata. Non-native P. maculata clutches significantly exceeded all other populations in all measured characteristics. Consequently, these traits may successfully distinguish between species. Fecundity data also allowed us to develop models that accurately estimated the number of eggs per clutch for each species based on clutch dimensions. We tested one, two and three dimensional models of clutches, including rendering a clutch as either a complete ellipsoid or an ellipsoid intersected by a cylinder to represent the oviposition site. Model comparisons found the product of length and depth, with a different function for each population, best predicted egg number for both species. Comparisons of egg number to clutch volume and mass implied non-native P. canaliculata may be food limited, while non-native P. maculata appeared to produce such enormous clutches by having access to greater nutrients than the native population. With these new tools, researchers and managers can quickly

  6. Count your eggs before they invade: identifying and quantifying egg clutches of two invasive apple snail species (Pomacea).

    PubMed

    Kyle, Colin H; Plantz, Allyson L; Shelton, Therese; Burks, Romi L

    2013-01-01

    Winning the war against invasive species requires early detection of invasions. Compared to terrestrial invaders, aquatic species often thrive undetected under water and do not garner notice until too late for early action. However, fortunately for managers, apple snails (Family Ampullariidae, Genus Pomacea) provide their own conspicuous sign of invasion in the form of vibrantly colored egg clutches. Managers can potentially use egg clutches laid in the riparian zone as a means of early detection and species identification. To facilitate such efforts, we quantified differences in characteristics (length, width, depth, mass, egg number) of field-laid clutches for the two most common invasive species of apple snail, P. canaliculata and P. maculata, in native and non-native populations. Pomacea canaliculata native and non-native populations differed noticeably only in width. Native P. maculata clutches possessed significantly greater width, mass and eggs numbers compared with native P. canaliculata. Non-native P. maculata clutches significantly exceeded all other populations in all measured characteristics. Consequently, these traits may successfully distinguish between species. Fecundity data also allowed us to develop models that accurately estimated the number of eggs per clutch for each species based on clutch dimensions. We tested one, two and three dimensional models of clutches, including rendering a clutch as either a complete ellipsoid or an ellipsoid intersected by a cylinder to represent the oviposition site. Model comparisons found the product of length and depth, with a different function for each population, best predicted egg number for both species. Comparisons of egg number to clutch volume and mass implied non-native P. canaliculata may be food limited, while non-native P. maculata appeared to produce such enormous clutches by having access to greater nutrients than the native population. With these new tools, researchers and managers can quickly

  7. Spatial variation in adult sex ratio across multiple scales in the invasive golden apple snail, Pomacea canaliculata.

    PubMed

    Xu, Meng; Fang, Miao; Yang, Yexin; Dick, Jaimie T A; Song, Hongmei; Luo, Du; Mu, Xidong; Gu, Dangen; Luo, Jianren; Hu, Yinchang

    2016-04-01

    Adult sex ratio (ASR) has critical effects on behavior and life history and has implications for population demography, including the invasiveness of introduced species. ASR exhibits immense variation in nature, yet the scale dependence of this variation is rarely analyzed. In this study, using the generalized multilevel models, we investigated the variation in ASR across multiple nested spatial scales and analyzed the underlying causes for an invasive species, the golden apple snail Pomacea canaliculata. We partitioned the variance in ASR to describe the variations at different scales and then included the explanatory variables at the individual and group levels to analyze the potential causes driving the variation in ASR. We firstly determined there is a significant female-biased ASR for this species when accounting for the spatial and temporal autocorrelations of sampling. We found that, counter to nearly equal distributed variation at plot, habitat and region levels, ASR showed little variation at the town level. Temperature and precipitation at the region level were significantly positively associated with ASR, whereas the individual weight, the density characteristic, and sampling time were not significant factors influencing ASR. Our study suggests that offspring sex ratio of this species may shape the general pattern of ASR in the population level while the environmental variables at the region level translate the unbiased offspring sex ratio to the female-biased ASR. Future research should consider the implications of climate warming on the female-biased ASR of this invasive species and thus on invasion pattern.

  8. Insights into Embryo Defenses of the Invasive Apple Snail Pomacea canaliculata: Egg Mass Ingestion Affects Rat Intestine Morphology and Growth

    PubMed Central

    Gimeno, Eduardo J.; Heras, Horacio

    2014-01-01

    Background The spread of the invasive snail Pomacea canaliculata is expanding the rat lungworm disease beyond its native range. Their toxic eggs have virtually no predators and unusual defenses including a neurotoxic lectin and a proteinase inhibitor, presumably advertised by a warning coloration. We explored the effect of egg perivitellin fluid (PVF) ingestion on the rat small intestine morphology and physiology. Methodology/Principal Findings Through a combination of biochemical, histochemical, histopathological, scanning electron microscopy, cell culture and feeding experiments, we analyzed intestinal morphology, growth rate, hemaglutinating activity, cytotoxicity and cell proliferation after oral administration of PVF to rats. PVF adversely affects small intestine metabolism and morphology and consequently the standard growth rate, presumably by lectin-like proteins, as suggested by PVF hemaglutinating activity and its cytotoxic effect on Caco-2 cell culture. Short-term effects of ingested PVF were studied in growing rats. PVF-supplemented diet induced the appearance of shorter and wider villi as well as fused villi. This was associated with changes in glycoconjugate expression, increased cell proliferation at crypt base, and hypertrophic mucosal growth. This resulted in a decreased absorptive surface after 3 days of treatment and a diminished rat growth rate that reverted to normal after the fourth day of treatment. Longer exposure to PVF induced a time-dependent lengthening of the small intestine while switching to a control diet restored intestine length and morphology after 4 days. Conclusions/Significance Ingestion of PVF rapidly limits the ability of potential predators to absorb nutrients by inducing large, reversible changes in intestinal morphology and growth rate. The occurrence of toxins that affect intestinal morphology and absorption is a strategy against predation not recognized among animals before. Remarkably, this defense is rather similar to

  9. A Pilot Study Testing a Natural and a Synthetic Molluscicide for Controlling Invasive Apple Snails (Pomacea maculata).

    PubMed

    Olivier, Heather M; Jenkins, Jill A; Berhow, Mark; Carter, Jacoby

    2016-03-01

    Pomacea maculata (formerly P. insularum), an apple snail native to South America, was discovered in Louisiana in 2008. These snails strip vegetation, reproduce at tremendous rates, and have reduced rice production and caused ecosystem changes in Asia. In this pilot study snails were exposed to two molluscicides, a tea (Camellia sinensis) seed derivative (TSD) or niclosamide monohydrate (Pestanal(®), 2',5-dichloro-4'-nitrosalicylanilide, CAS #73360-56-2). Mortality was recorded after exposure to high or low concentrations (0.03 and 0.015 g/L for TSD, 1.3 and 0.13 mg/L for niclosamide). The TSD induced 100 % mortality at both concentrations. Niclosamide caused 100 % and 17 % mortality at high and low concentrations respectively. These molluscicides were also tested on potential biocontrol agents, the red swamp crayfish (Procambarus clarkii) and redear sunfish (Lepomis microlophus). No crayfish mortalities occurred at either concentration for either chemical, but sunfish experienced 100 % mortality with TSD (0.03 g/L), and 21 % mortality with niclosamide (0.13 mg/L).

  10. A pilot study testing a natural and a synthetic Molluscicide for controlling invasive apple snails (Pomacea maculata)

    USGS Publications Warehouse

    Olivier, Heather M.; Jenkins, Jill A.; Berhow, Mark; Carter, Jacoby

    2016-01-01

    Pomacea maculata (formerly P. insularum), an apple snail native to South America, was discovered in Louisiana in 2008. These snails strip vegetation, reproduce at tremendous rates, and have reduced rice production and caused ecosystem changes in Asia. In this pilot study snails were exposed to two molluscicides, a tea (Camellia sinensis) seed derivative (TSD) or niclosamide monohydrate (Pestanal®, 2′,5-dichloro-4′-nitrosalicylanilide, CAS #73360-56-2). Mortality was recorded after exposure to high or low concentrations (0.03 and 0.015 g/L for TSD, 1.3 and 0.13 mg/L for niclosamide). The TSD induced 100 % mortality at both concentrations. Niclosamide caused 100 % and 17 % mortality at high and low concentrations respectively. These molluscicides were also tested on potential biocontrol agents, the red swamp crayfish (Procambarus clarkii) and redear sunfish (Lepomis microlophus). No crayfish mortalities occurred at either concentration for either chemical, but sunfish experienced 100 % mortality with TSD (0.03 g/L), and 21 % mortality with niclosamide (0.13 mg/L).

  11. 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

  12. Endosymbiotic and Host Proteases in the Digestive Tract of the Invasive Snail Pomacea canaliculata: Diversity, Origin and Characterization

    PubMed Central

    Godoy, Martín S.; Castro-Vasquez, Alfredo; Vega, Israel A.

    2013-01-01

    Digestive proteases of the digestive tract of the apple snail Pomacea canaliculata were studied. Luminal protease activity was found in the crop, the style sac and the coiled gut and was significantly higher in the coiled gut. Several protease bands and their apparent molecular weights were identified in both tissue extracts and luminal contents by gel zymography: (1) a 125 kDa protease in salivary gland extracts and in the crop content; (2) a 30 kDa protease throughout all studied luminal contents and in extracts of the midgut gland and of the endosymbionts isolated from this gland; (3) two proteases of 145 and 198 kDa in the coiled gut content. All these proteases were inhibited by aprotinin, a serine-protease inhibitor, and showed maximum activity between 30°C and 35°C and pH between 8.5 and 9.5. Tissue L-alanine-N-aminopeptidase activity was determined in the wall of the crop, the style sac and the coiled gut and was significantly higher in the coiled gut. Our findings show that protein digestion in P. canaliculata is carried out through a battery of diverse proteases originated from the salivary glands and the endosymbionts lodged in the midgut gland and by proteases of uncertain origin that occur in the coiled gut lumen. PMID:23818959

  13. Immune Defenses of the Invasive Apple Snail Pomacea canaliculata (Caenogastropoda, Ampullariidae): Phagocytic Hemocytes in the Circulation and the Kidney

    PubMed Central

    Vega, Israel A.; Castro-Vazquez, Alfredo

    2015-01-01

    Hemocytes in the circulation and kidney islets, as well as their phagocytic responses to microorganisms and fluorescent beads, have been studied in Pomacea canaliculata, using flow cytometry, light microscopy (including confocal laser scanning microscopy) and transmission electron microscopy (TEM). Three circulating hemocyte types (hyalinocytes, agranulocytes and granulocytes) were distinguished by phase contrast microscopy of living cells and after light and electron microscopy of fixed material. Also, three different populations of circulating hemocytes were separated by flow cytometry, which corresponded to the three hemocyte types. Hyalinocytes showed a low nucleus/cytoplasm ratio, and no apparent granules in stained material, but showed granules of moderate electron density under TEM (L granules) and at least some L granules appear acidic when labeled with LysoTracker Red. Both phagocytic and non-phagocytic hyalinocytes lose most (if not all) L granules when exposed to microorganisms in vitro. The phagosomes formed differed whether hyalinocytes were exposed to yeasts or to Gram positive or Gram negative bacteria. Agranulocytes showed a large nucleus/cytoplasm ratio and few or no granules. Granulocytes showed a low nucleus/cytoplasm ratio and numerous eosinophilic granules after staining. These granules are electron dense and rod-shaped under TEM (R granules). Granulocytes may show merging of R granules into gigantic ones, particularly when exposed to microorganisms. Fluorescent bead exposure of sorted hemocytes showed phagocytic activity in hyalinocytes, agranulocytes and granulocytes, but the phagocytic index was significantly higher in hyalinocytes. Extensive hemocyte aggregates ('islets') occupy most renal hemocoelic spaces and hyalinocyte-like cells are the most frequent component in them. Presumptive glycogen deposits were observed in most hyalinocytes in renal islets (they also occur in the circulation but less frequently) and may mean that hyalinocytes

  14. 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.

  15. Importance of Macrophyte Quality in Determining Life-History Traits of the Apple Snails Pomacea canaliculata: Implications for Bottom-Up Management of an Invasive Herbivorous Pest in Constructed Wetlands

    PubMed Central

    Yam, Rita S. W.; Fan, Yen-Tzu; Wang, Tzu-Ting

    2016-01-01

    Pomacea canaliculata (Ampullariidae) has extensively invaded most Asian constructed wetlands and its massive herbivory of macrophytes has become a major cause of ecosystem dysfunctioning of these restored habitats. We conducted non-choice laboratory feeding experiments of P. canaliculata using five common macrophyte species in constructed wetlands including Ipomoea aquatica, Commelina communis, Nymphoides coreana, Acorus calamus and Phragmites australis. Effects of macrophytes on snail feeding, growth and fecundity responses were evaluated. Results indicated that P. canaliculata reared on Ipomoea had the highest feeding and growth rates with highest reproductive output, but all individuals fed with Phragmites showed lowest feeding rates and little growth with poorest reproductive output. Plant N and P contents were important for enhancing palatability, supporting growth and offspring quantity of P. canaliculata, whilst toughness, cellulose and phenolics had critically deterrent effects on various life-history traits. Although snail offspring quality was generally consistent regardless of maternal feeding conditions, the reduced growth and offspring quantity of the poorly-fed snails in constructed wetlands dominated by the less-palatable macrophytes could limit the invasive success of P. canaliculata. Effective bottom-up control of P. canaliculata in constructed wetlands should involve selective planting strategy using macrophytes with low nutrient and high toughness, cellulose and phenolic contents. PMID:26927135

  16. Importance of Macrophyte Quality in Determining Life-History Traits of the Apple Snails Pomacea canaliculata: Implications for Bottom-Up Management of an Invasive Herbivorous Pest in Constructed Wetlands.

    PubMed

    Yam, Rita S W; Fan, Yen-Tzu; Wang, Tzu-Ting

    2016-02-24

    Pomacea canaliculata (Ampullariidae) has extensively invaded most Asian constructed wetlands and its massive herbivory of macrophytes has become a major cause of ecosystem dysfunctioning of these restored habitats. We conducted non-choice laboratory feeding experiments of P. canaliculata using five common macrophyte species in constructed wetlands including Ipomoea aquatica, Commelina communis, Nymphoides coreana, Acorus calamus and Phragmites australis. Effects of macrophytes on snail feeding, growth and fecundity responses were evaluated. Results indicated that P. canaliculata reared on Ipomoea had the highest feeding and growth rates with highest reproductive output, but all individuals fed with Phragmites showed lowest feeding rates and little growth with poorest reproductive output. Plant N and P contents were important for enhancing palatability, supporting growth and offspring quantity of P. canaliculata, whilst toughness, cellulose and phenolics had critically deterrent effects on various life-history traits. Although snail offspring quality was generally consistent regardless of maternal feeding conditions, the reduced growth and offspring quantity of the poorly-fed snails in constructed wetlands dominated by the less-palatable macrophytes could limit the invasive success of P. canaliculata. Effective bottom-up control of P. canaliculata in constructed wetlands should involve selective planting strategy using macrophytes with low nutrient and high toughness, cellulose and phenolic contents.

  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%.

  18. 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.

  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. 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.

  1. Isolation and Characterization of Sixteen Polymorphic Microsatellite Loci in the Golden Apple Snail Pomacea canaliculata

    PubMed Central

    Chen, Lian; Xu, Haigen; Li, Hong; Wu, Jun; Ding, Hui; Liu, Yan

    2011-01-01

    We report the characterization of 16 polymorphic microsatellite markers in the golden apple snail, Pomacea canaliculata, a pest registered in the list of “100 of the world’s worst invasive alien species”. The fast isolation by AFLP (Amplified Fragment Length Polymorphism) of sequences containing repeats (FIASCO) method was used to isolate microsatellite loci, and polymorphism was explored with 29 individuals collected in an invasive region from China. These primers showed a number of alleles per locus ranging from three to 13. The ranges of observed and expected heterozygosity were 0.310–0.966 and 0.523–0.898, respectively. These microsatellite markers described here will be useful for population genetic studies of P. canaliculata. PMID:22016640

  2. Isolation and characterization of sixteen polymorphic microsatellite loci in the golden apple snail Pomacea canaliculata.

    PubMed

    Chen, Lian; Xu, Haigen; Li, Hong; Wu, Jun; Ding, Hui; Liu, Yan

    2011-01-01

    We report the characterization of 16 polymorphic microsatellite markers in the golden apple snail, Pomacea canaliculata, a pest registered in the list of "100 of the world's worst invasive alien species". The fast isolation by AFLP (Amplified Fragment Length Polymorphism) of sequences containing repeats (FIASCO) method was used to isolate microsatellite loci, and polymorphism was explored with 29 individuals collected in an invasive region from China. These primers showed a number of alleles per locus ranging from three to 13. The ranges of observed and expected heterozygosity were 0.310-0.966 and 0.523-0.898, respectively. These microsatellite markers described here will be useful for population genetic studies of P. canaliculata.

  3. 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.

  4. 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.

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

    PubMed

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

    2008-10-01

    The present study characterized copper (Cu) uptake and depuration by juvenile and adult Florida apple snails (Pomacea paludosa) from water, soil, and diet. During a 28-day uptake period, juvenile apple snails were exposed to aqueous Cu and adult apple snails were exposed to Cu-contaminated soil, water, and food. In the follow-up 14-day depuration period, both juvenile and adult apple snails were held in laboratory freshwater with background Cu concentrations<4 microg/l. For juvenile apple snails, whole body Cu concentrations increased with time and reached a plateau after 14 days. The data followed Michaelis-Menten kinetics rather than a one compartment first order kinetics model. The mean Cu bioconcentration factor (BCF) for juvenile apple snails was 1493 and the depuration half-life was 10.5-13.8 days. For adult snails, dietary uptake of Cu resulted in higher bioaccumulation factors (BAFs) compared to uptake from soil. Most of the accumulated Cu was located in soft tissue (about 60% in the viscera and 40% in the foot). The shell contained <1% of the total accumulated copper. Soft tissue is usually consumed by predators of the apple snail. Therefore, the results of the present study show that Cu transfer through the food chain to the apple snail may lead to potential risk to its predators.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. Searching for doubly uniparental inheritance of mtDNA in the apple snail Pomacea diffusa.

    PubMed

    Parakatselaki, Maria Eleni; Saavedra, Carlos; Ladoukakis, Emmanuel D

    2016-11-01

    Doubly uniparental inheritance (DUI) of mitochondrial DNA (mtDNA) is an exceptional mode of mtDNA transmission, restricted so far to the class of bivalves. We searched for DUI outside bivalves using the apple snail Pomacea diffusa. It was an appropriate candidate to search for DUI for three reasons; it belongs to gastropods, which is the closest sister group to bivalves, it is gonochoristic and it has a strong sex bias in the progeny of different female individuals. These phenomena (gonochorism and sex-biased progeny) are also found in species with DUI. We searched for heteroplasmy in males and for high sequence divergence among mtDNA sequences obtained from male and female gonads. All sequences examined were identical. These data suggest that the mtDNA in P. diffusa is maternally transmitted and DUI remains an exclusive characteristic of bivalves.

  12. Imposex and novel mechanisms of reproductive failure induced by tributyltin (TBT) in the freshwater snail Pomacea canaliculata.

    PubMed

    Giraud-Billoud, Maximiliano; Vega, Israel A; Wuilloud, Rodolfo G; Clément, María E; Castro-Vazquez, Alfredo

    2013-10-01

    The effects of tributyltin (TBT) on mortality and reproduction were studied in the invasive snail Pomacea canaliculata. The nominal median lethal concentration (LC50) was 9 µg TBT/L, after 28 d. The nominal no-observed effect on lethality concentration (NOECL) was 6 µg TBT/L after the same period. Male-female couples and females that had been group-mated but were isolated from males during the experiment (isolated females) were exposed (for 28 d) to either 0 µg/L or 6 µg/L of TBT (nominal NOECL-exposed). Copulation and oviposition frequencies, egg clutch mass, and percentage of egg fertility were recorded. Gonads (both sexes) and the seminal receptacle (females) were studied histologically at the end of the experiment. A significant decrease in copulation frequency was observed in mated-exposed females. Exposure also decreased oviposition frequency of mated-exposed and isolated-exposed females, but only the latter reached significance. No differences in either egg clutch mass or percentage of fertility were observed at first oviposition, but both parameters were drastically reduced in subsequent egg clutches of exposed females. No histological alterations were observed in gonads of TBT-exposed animals; however, sperm storage in the seminal receptacle was drastically decreased in exposed females. Imposex but no oviductal obstruction was observed in all exposed females. It is concluded that TBT induces reproductive failure in P. canaliculata by decreasing copulation frequency and by severely affecting sperm storage by the female.

  13. 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.

  14. 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 96 h were 330, 223, 177 and 146 µg/L, respectively. P. canaliculata were exposed to Cu at 146 µg/L for 96 h 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.

  15. 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

    2008-07-09

    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.

  16. 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.

  17. The effect of stocking density on the growth of apple snails native Pomacea bridgesii and exotic Pomacea lineata (Mollusca, Gastropoda).

    PubMed

    Souza Júnior, Esmar; De Barros, José Carlos N; Paresque, Karla; De Freitas, Rodrigo R

    2013-01-01

    The demand for alternative food sources is currently in evidence in the world and, therefore, the culture of animal species considered not conventional makes this theme relevant and appropriate. In the present study, the species Pomacea lineata and Pomacea bridgesii, each with three stowage densities (0.5 [T1], 1 [T2], and 1.5 [T3] animal/L), were tested. They were analyzed regarding growth rate, weight gain, final biomass, feed conversion and percentage of survival. There was not any statistically significant difference between the different densities for both species. The final average weight in the three waterworks did not differ significantly in P. bridgesii. In P. lineata, T1 (22.3 ± 1.80g) was significantly higher than T2 and T3. On the other hand, the absolute gain of weight in P. lineata and P. bridgesii was significantly higher in T1 (21.9 ± 1.80g and 37.2 ± 6.34g) than in T2 and T3 respectively. In contrast, the gain of biomass of P. lineata and P. bridgesii was significantly higher in T3 (276.3 ± 33.16g and 431.4 ± 37.20g) than in T1 and T2, respectively. Based on the results obtained, all species studied presented potential for aquaculture, mainly P. bridgesii, distinguished for showing a better development even in waterworks with higher densities.

  18. Effects of dietary supplementation of golden apple snail (Pomacea canaliculata) egg on survival, pigmentation and antioxidant activity of Blood parrot.

    PubMed

    Yang, Song; Liu, Qiao; Wang, Yue; Zhao, Liu-Lan; Wang, Yan; Yang, Shi-Yong; Du, Zong-Jun; Zhang, Jia-En

    2016-01-01

    This study aims to evaluate the effects of supplementing golden apple snail (Pomacea canaliculata) eggs powder (EP) in the diet as a source of natural carotenoids on survival, pigmentation and antioxidant activity of Blood parrot. A total of 90 fish were divided into three treatment groups with three replicates per treatment. Blood parrot were fed with diets containing 0 (control), 5 % (EP 5 %), and 15 % (EP 15 %) dry powder of golden apple snail egg for 60 days, and nine fish per group were sampled at 20, 40, and 60 days. No differences in survival of the fish among treatments were found throughout the experiment. The body coloration of Blood parrot was enhanced in the skin and caudal fin with increasing content of golden apple snail egg powder in the diet. At the end of the experiment, the carotenoid content in the caudal fin and the number of scale chromatophores of the fish fed dietary with EP were higher (P < 0.05) than those of the control group. The EP 15 % treated fishes showed a significant higher (P < 0.05) in the activities of SOD after 60 days, but we could not observe significant changes (P > 0.05) in CAT activities. Results demonstrated that golden apple snail eggs can be used as a colorant to promote the pigmentation efficacy of Blood parrot.

  19. Comparative Functional Responses Predict the Invasiveness and Ecological Impacts of Alien Herbivorous Snails

    PubMed Central

    Xu, Meng; Mu, Xidong; Dick, Jaimie T. A.; Fang, Miao; Gu, Dangen; Luo, Du; Zhang, Jiaen; Luo, Jianren; Hu, Yinchang

    2016-01-01

    Understanding determinants of the invasiveness and ecological impacts of alien species is amongst the most sought-after and urgent research questions in ecology. Several studies have shown the value of comparing the functional responses (FRs) of alien and native predators towards native prey, however, the technique is under-explored with herbivorous alien species and as a predictor of invasiveness as distinct from ecological impact. Here, in China, we conducted a mesocosm experiment to compare the FRs among three herbivorous snail species: the golden apple snail, Pomacea canaliculata, a highly invasive and high impact alien listed in “100 of the World's Worst Invasive Alien Species”; Planorbarius corneus, a non-invasive, low impact alien; and the Chinese native snail, Bellamya aeruginosa, when feeding on four locally occurring plant species. Further, by using a numerical response equation, we modelled the population dynamics of the snail consumers. For standard FR parameters, we found that the invasive and damaging alien snail had the highest “attack rates” a, shortest “handling times” h and also the highest estimated maximum feeding rates, 1/hT, whereas the native species had the lowest attack rates, longest handling times and lowest maximum feeding rates. The non-invasive, low impact alien species had consistently intermediate FR parameters. The invasive alien species had higher population growth potential than the native snail species, whilst that of the non-invasive alien species was intermediate. Thus, while the comparative FR approach has been proposed as a reliable method for predicting the ecological impacts of invasive predators, our results further suggest that comparative FRs could extend to predict the invasiveness and ecological impacts of alien herbivores and should be explored in other taxa and trophic groups to determine the general utility of the approach. PMID:26771658

  20. Comparative Functional Responses Predict the Invasiveness and Ecological Impacts of Alien Herbivorous Snails.

    PubMed

    Xu, Meng; Mu, Xidong; Dick, Jaimie T A; Fang, Miao; Gu, Dangen; Luo, Du; Zhang, Jiaen; Luo, Jianren; Hu, Yinchang

    2016-01-01

    Understanding determinants of the invasiveness and ecological impacts of alien species is amongst the most sought-after and urgent research questions in ecology. Several studies have shown the value of comparing the functional responses (FRs) of alien and native predators towards native prey, however, the technique is under-explored with herbivorous alien species and as a predictor of invasiveness as distinct from ecological impact. Here, in China, we conducted a mesocosm experiment to compare the FRs among three herbivorous snail species: the golden apple snail, Pomacea canaliculata, a highly invasive and high impact alien listed in "100 of the World's Worst Invasive Alien Species"; Planorbarius corneus, a non-invasive, low impact alien; and the Chinese native snail, Bellamya aeruginosa, when feeding on four locally occurring plant species. Further, by using a numerical response equation, we modelled the population dynamics of the snail consumers. For standard FR parameters, we found that the invasive and damaging alien snail had the highest "attack rates" a, shortest "handling times" h and also the highest estimated maximum feeding rates, 1/hT, whereas the native species had the lowest attack rates, longest handling times and lowest maximum feeding rates. The non-invasive, low impact alien species had consistently intermediate FR parameters. The invasive alien species had higher population growth potential than the native snail species, whilst that of the non-invasive alien species was intermediate. Thus, while the comparative FR approach has been proposed as a reliable method for predicting the ecological impacts of invasive predators, our results further suggest that comparative FRs could extend to predict the invasiveness and ecological impacts of alien herbivores and should be explored in other taxa and trophic groups to determine the general utility of the approach.

  1. The effects of water quality and age on the acute toxicity of copper to the Florida apple snail, Pomacea paludosa.

    PubMed

    Rogevich, E C; Hoang, T C; Rand, G M

    2008-05-01

    Copper (Cu)-containing compounds have been used in Florida as fungicides, herbicides, and soil amendments, resulting in elevated Cu in the aquatic ecosystem. The Florida apple snail (Pomacea paludosa), a key species in south Florida, may be adversely affected by Cu. Water-quality parameters, such as hardness, dissolved organic carbon (DOC), pH, and alkalinity, affect metal bioavailability and toxicity in aquatic organisms; however, it is uncertain to what extent these factors affect Cu toxicity in the Florida apple snail. The research presented here characterized the acute (96-hour) toxicity of Cu in water to the Florida apple snail at various life stages and under different water-quality parameters. Cu was more toxic to juvenile than adult apple snails. There was no difference between the 96-hour LC(50) at pH 5.5 and 6.5; however, the 96-hour LC(50 )values at pH 7.5 and 8.5 were greater than at lower pHs. The decrease in Cu(2+) above pH 7, as predicted by the MINTEQ model, accounted for the pH effect. Cu toxicity decreased as DOC increased from 0.2 to 30 mg/L. Unlike other aquatic organisms, hardness had no effect on Cu toxicity to the Florida apple snail, suggesting another mechanism of toxicity. Whole-body tissue analysis indicated that the lethal body burden of 120-day-old snails exposed to Cu for 4 days was 30 mg/kg Cu dry weight. Multiple regression analysis indicated that Cu toxicity was a function of organism age, DOC, and pH.

  2. Angiostrongylus cantonensis in the vector snails Pomacea canaliculata and Achatina fulica in China: a meta-analysis.

    PubMed

    Song, Langui; Wang, Xiaowen; Yang, Zi; Lv, Zhiyue; Wu, Zhongdao

    2016-03-01

    Angiostrongyliasis is a food-borne parasitic disease induced by the nematode Angiostrongylus cantonensis, and has been recognized as the main cause leading to human eosinophilic meningitis. Humans usually acquire infection by digestion of infected Pomacea canaliculata and Achatina fulica, the most predominant intermediate hosts found in China. This meta-analysis was aimed to assess the prevalence of A. cantonensis infection among these two snails in China in the past 10 years. Data were systematically collected in electronic databases such as PubMed, Web of Science, ScienceDirect, CNKI, SinoMed, VIP, CSCD, and Wanfang from 2005 to 2015. Thirty-eight studies with a total of 41,299 P. canaliculata and 21,138 Ac. fulica were included in the present study. The overall infection rate of A. cantonensis in China was estimated to be 7.6 % (95 % confidential interval (CI) = 0.063 to 0.090) in P. canaliculata and 21.5 % in Ac. fulica (95 % CI = 0.184 to 0.245), respectively. No significant difference was observed in prevalence rates among publication year and sample size for both snails. Also, it was found that the prevalence in Ac. fulica is significantly higher than that in P. canaliculata (odds ratio (OR) = 3.946, 95 % CI = 3.070 to 5.073). The present study reveals that snail infection with A. cantonensis is clearly prevalent in China. Further studies are required to improve strategies for control of infections of snails, particularly those of Ac. fulica, and to detect further factors and conditions such as geographic region, temperatures, and diagnosis method.

  3. Cloning, genomic organization and expression of two glycosyl hydrolase family 10 (GHF10) genes from golden apple snail (Pomacea canaliculata).

    PubMed

    Imjongjirak, Chanprapa; Amparyup, Piti; Sittipraneed, Siriporn

    2008-06-01

    Two cellulase cDNAs (GHF10-Pc1 and GHF10-Pc3) belonging to glycoside hydrolase family 10 (GHF10) were successfully isolated and characterized from stomach tissue of golden apple snail (Pomacea canaliculata), a kind of herbivorous mollusca. Sequencing analysis revealed full-length cDNAs of 1300 and 1277 bp in length, respectively. The open reading frame (ORF) of cellulase cDNA was 1188 and 1191 bp, encoding 395 and 396 amino acid, respectively. Sequence alignment revealed that GHF10-Pc1 and GHF10-Pc3 shared high identity with glycosyl hydrolase family 10 (GHF10) and had an overall similarity of 98 and 82% to those of Ampullaria crossean cellulase EGX. A neighbour-joining tree showed a clear differentiation between each species and also indicated that GHF10-Pc1 and GHF10-Pc3 from P. canaliculata and A. crossean EGX are closely related phylogenetically. The genomic organization of cellulase GHF10-Pc1 and GHF10-Pc3 genes was also investigated. The GHF10-Pc1 and GHF10-Pc3 genes spanned over 4937 and 4512 bp, respectively. Both genes contained 9 exons interrupted by eight introns. The result verified the endogenous origin of the GHF10-Pc1 and GHF10-Pc3 genes. Analysis of RNA by RT-PCR from several ages of P. canaliculata revealed that neither gene was expressed in eggs. GHF10-Pc1 was also expressed in 1- and 10-day-old juvenile snails whereas GHF10-Pc3 was expressed only in 1-day-old juvenile snails. The result showed that two GHF10-Pc transcripts were developmentally expressed.

  4. Histopathological effects of contaminated sediments on golden apple snail (Pomacea canaliculata, Lamarck 1822).

    PubMed

    Kruatrachue, M; Sumritdee, C; Pokethitiyook, P; Singhakaew, S

    2011-06-01

    Pomacea canaliculata were exposed experimentally to contaminated sediments from a tributary of the Mae Klong River, Thailand, for 3 months. The highest concentration of Cr, Zn and Fe accumulated in the digestive gland while the gill exhibited the highest concentration of Cu. In addition, histopathological changes (increased mucus vacuoles, loss of cilia, dilation of cells in the epithelial cells of digestive tract organs, and an increase in the number of dark granules in the digestive cells) were observed. The gill exhibited loss of cilia, wider hemolymph space, and degeneration of columnar epithelial cells.

  5. 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

  6. Molecular cloning, characterization and expression analysis of HSP60, HSP70 and HSP90 in the golden apple snail, Pomacea canaliculata.

    PubMed

    Xu, Yipeng; Zheng, Guowan; Dong, Shengzhang; Liu, Guangfu; Yu, Xiaoping

    2014-12-01

    The golden apple snail, Pomacea canaliculata, has strong tolerance to high temperature, facilitating its invasion in East and Southeast Asia. In the present study, three cDNAs encoding heat shock proteins (PocaHSP60, PocaHSP70, PocaHSP90) in P. canaliculata were cloned and characterized. The PocaHSP60 cDNA was 2447 bp, containing an ORF encoding a polypeptide of 574 amino acids. The PocaHSP70 cDNA was 2644 bp, containing an ORF encoding a polypeptide of 643 amino acids. The PocaHSP90 cDNA was 2546 bp, containing an ORF encoding a polypeptide of 726 amino acids. Genomic DNA analysis showed that PocaHSP60 had 11 introns in the coding region and PocaHSP90 had 7 introns but PocaHSP70 had no one. The expression changes of these three PocaHSPs in the gill, digestive gland, kidney and foot muscle of P. canaliculata exposed to high and low temperature were investigated. The results of quantitative PCR and western blotting showed that the expression level of PocaHSP90 was much higher than PocaHSP60 and PocaHSP70 at room temperature, and PocaHSP70 expression level was the lowest among them. Afterheat shock, PocaHSP70 expression increased rapidly, much more significantly than PocaHSP90 expression, and the effect of heat shock on the expression of PocaHSP70 and PocaHSP90 in the different tissues of P. canaliculata was not the same. Unlike PocaHSP70 and PocaHSP90, PocaHSP60 expression seemed not to be affected by heat shock, because its expression was moderately induced only in the foot muscle. However, cool shock had little effect on the expression change of above three PocaHSPs. These results indicated that HSPs might be related to the thermal resistance of P. canaliculata.

  7. Lipoproteins of the egg perivitelline fluid of Pomacea canaliculata snails (Mollusca: Gastropoda).

    PubMed

    Garin, C F; Heras, H; Pollero, R J

    1996-12-01

    The lipid and protein composition of the perivitelline fluid of the eggs of Pomacea canaliculata was investigated. Two lipoproteins (PV 1 and PV 2) and one lipoprotein fraction (PV 3) were detected for the first time in gastropods. They represent 57.0, 7.5, and 35.5% of the egg total proteins, respectively. PV 1 is a glyco-carotene-protein complex with characteristics of a very high-density lipoprotein (VHDL). It has 0.33% lipids, mainly free sterols and phospholipids. The particle has a MW of 300 Kd and is composed of three subunits of 35, 32, and 28 Kd, respectively. PV 2 particle is a VHDL of 400 Kd and 3.75% lipids. The major lipid classes are free sterols and phospholipids and also have significant quantities of energy-providing triacylglycerides and free fatty acids. It is composed of two apoproteins of 67 and 31 Kd. PV 3 density corresponds to a high-density lipoprotein (HDL). It was fractionated into two subfractions "h" and "p". Fraction "h" contains 5.16% lipids, mainly free sterols, phospholipids, and free fatty acids, and two particles of 100 and 64 Kd. Dissociating electrophoresis showed two subunits of 34 and 29 Kd. Fraction "p" is composed of a single particle of 26 Kd that contains 9.5% lipids, which represents 30% of the total egg lipids. It has high levels of a carotenoid pigment. Besides it contains free fatty acids, hydrocarbons, sterified sterols, and triacylglycerides. These three fractions are probably the major supply of lipids and amino acids for the developing embryo.

  8. The mitochondrial genome of Pomacea maculata (Gastropoda: Ampullariidae).

    PubMed

    Yang, Qianqian; Liu, Suwen; Song, Fan; Li, Hu; Liu, Jinpeng; Liu, Guangfu; Yu, Xiaoping

    2016-07-01

    The golden apple snail, Pomacea maculata Perry, 1810 (Gastropoda: Ampullariidae) is one of the most serious invasive alien species from the native range of South America. The mitochondrial genome of P. maculata (15 516 bp) consists of 37 genes (13 protein-coding genes, two rRNAs, and 22 tRNAs) and a non-coding region with a 16 bp repeat unit. Most mitochondrial genes of P. maculata are distributed on the H-strand, except eight tRNA genes, which are encoded on the L-strand. A phylogenetic analysis showed that there was a close relationship between P. maculata and another invasive golden apple snail species, Pomacea canaliculata (Lamarck, 1822).

  9. Snail promotes an invasive phenotype in lung carcinoma

    PubMed Central

    2012-01-01

    Background Snail is a transcriptional factor which is known to influence the epitheliomesenchymal transition (EMT) by regulating adhesion proteins such as E-cadherin and claudins as well as matrix metalloproteases (MMP). Methods To evaluate the functional importance of snail, a transciptional factor involved in EMT in lung tumors, we investigated its expression in a large set of lung carcinomas by immunohistochemistry. Expression of snail and effects of snail knockdown was studied in cell lines. Results Nuclear snail expression was seen in 21% of cases this being strongest in small cell lung carcinomas (SCLC). There was significantly greater snail expression in SCLC compared to squamous cell or adenocarcinoma. Positive snail expression was associated with poor survival in the whole material and separately in squamous cell and adenocarcinomas. In Cox regression analysis, snail expression showed an independent prognostic value in all of these groups. In several cell lines knockdown of snail reduced invasion in both matrigel assay and in the myoma tissue model for invasion. The influence of snail knockdown on claudin expression was cell type specific. Snail knockdown in these cell lines modified the expression of MMP2 and MMP9 but did not influence the activation of these MMPs to any significant degree. Conclusions The results show that snail plays an important role in the invasive characteristics of lung carcinoma influencing the survival of the patients. Snail knockdown might thus be one option for targeted molecular therapy in lung cancer. Snail knockdown influenced the expression of claudins individually in a cell-line dependent manner but did not influence MMP expressions or activations to any significant degree. PMID:23157169

  10. Localization of ghrelin-like peptide in the gastrointestinal tract of the golden apple snail (Pomacea canaliculata) and changing of its concentration during fasting.

    PubMed

    Ngernsoungnern, Apichart; Ngernsoungnern, Piyada

    2016-04-01

    Ghrelin is an endogenous hormone detected in the gastrointestinal tracts (GI) of various species. In the present study, ghrelin-like peptide (ghrelin-LP) was identified in the GI tract of the golden apple snail, Pomacea canaliculata. Using immunohistochemistry, the result revealed an immunoreactivity (-ir) of ghrelin-LP in regions of the GI tract. The ghrelin-LP-ir was observed in both opened-type and closed-type cells of the esophagus, stomach, and small and large intestines. The highest density of ghrelin-LP immunoreactive cells was found in the esophagus and the least density was detected in the stomach. The highest percentages of the opened-type and closed-type cells were present in the esophagus and small intestine, respectively. In immunoblotting, the molecular weight of ghrelin-LP was related to the human ghrelin peptide (∼13kDa). Moreover, the concentration of ghrelin-LP was significantly higher in snails that were fasted for 24h compared with fed snails. The concentration decreased after refeeding. The present study could be useful for understanding the physiological role of ghrelin-LP in mollusk species.

  11. The Apple Snail Pomacea maculata (Caenogastropoda: Ampullariidae) as the intermediate host of Stomylotrema gratiosus (Trematoda: Stomylotrematidae) in Brazil: the first report of a mollusc host of a Stomylotrematid Trematode.

    PubMed

    Pinto, Hudson A; Cantanhede, Selma Patrícia D; Thiengo, Silvana C; de Melo, Alan L; Fernandez, Monica A

    2015-04-01

    Trematodes belonging to the family Stomylotrematidae are intestinal parasites of birds. Despite the worldwide distribution and diversity of host species, the first intermediate host remains unknown. For a survey of parasites of Pomacea maculata , snails were collected from the municipality of São Vicente Férrer, state of Maranhão, northeastern Brazil. In the present study, the xiphidiocercariae shed from these snails were used in the experimental infection of the water bug Belostoma plebejum. The insect mortality was observed 30 days post-infection, and the metacercariae recovered in the body cavity of B. plebejum were identified as Stomylotrema gratiosus. This is the first report of an ampullariid snail as intermediate host of stomylotrematid trematodes.

  12. Molecular characteristics of the HSP70 gene and its differential expression in female and male golden apple snails (Pomacea canaliculata) under temperature stimulation.

    PubMed

    Song, Hong-Mei; Mu, Xi-Dong; Gu, Dang-En; Luo, Du; Yang, Ye-Xin; Xu, Meng; Luo, Jian-Ren; Zhang, Jia-En; Hu, Yin-Chang

    2014-07-01

    Heat-shock protein 70 (HSP70) is one of the most important heat-shock proteins that helps organisms to modulate stress response via over-expression. The HSP70 gene from Pomacea canaliculata was cloned using the RACE approach; the gene is 2,767 bp in length and contains an open reading frame of 1,932 bp, which is encoded by a polypeptide of 643 amino acids. BLAST analysis showed that the predicted amino acid sequence of the P. canaliculata HSP70 gene shared a relatively high similarity with that of other known eukaryotic species that display conserved HSP characteristics. The phylogeny demonstrated a separate clustering of the apple snail HSP70 with other constitutive members from other mollusk species. Quantitative real-time RT-PCR was used to detect the differential expression of HSP70 in both sexes of P. canaliculata at different temperature conditions. These results showed that HSP70 transcript levels decreased slightly under cold shock and increased significantly under heat-shock conditions in both sexes compared to normal temperatures (26 °C). Under cold-shock treatment, the sex effect was not significant. With heat treatment, HSP70 expression could be induced at 36 °C in both females and males, and it peaked at 42 and 39 °C in females and males, respectively. In addition, a clear time-dependent HSP70 expression pattern of the apple snail exposed to the same high temperature (36 °C) was observed at different time points. The maximal induction of HSP70 expression appeared at 12 and 48 h in males and females after heat shock, respectively. The maximal induction in females was significantly higher compared to males under heat stimulus. Taken together, these results strongly suggested that males were more susceptible to heat than females and provided useful molecular information for the ecological adaptability of P. canaliculata against extreme environmental stress.

  13. Dub3 inhibition suppresses breast cancer invasion and metastasis by promoting Snail1 degradation.

    PubMed

    Wu, Yadi; Wang, Yu; Lin, Yiwei; Liu, Yajuan; Wang, Yifan; Jia, Jianhang; Singh, Puja; Chi, Young-In; Wang, Chi; Dong, Chenfang; Li, Wei; Tao, Min; Napier, Dana; Shi, Qiuying; Deng, Jiong; Mark Evers, B; Zhou, Binhua P

    2017-02-15

    Snail1, a key transcription factor of epithelial-mesenchymal transition (EMT), is subjected to ubiquitination and degradation, but the mechanism by which Snail1 is stabilized in tumours remains unclear. We identify Dub3 as a bona fide Snail1 deubiquitinase, which interacts with and stabilizes Snail1. Dub3 is overexpressed in breast cancer; knockdown of Dub3 resulted in Snail1 destabilization, suppressed EMT and decreased tumour cell migration, invasion, and metastasis. These effects are rescued by ectopic Snail1 expression. IL-6 also stabilizes Snail1 by inducing Dub3 expression, the specific inhibitor WP1130 binds to Dub3 and inhibits the Dub3-mediating Snail1 stabilization in vitro and in vivo. Our study reveals a critical Dub3-Snail1 signalling axis in EMT and metastasis, and provides an effective therapeutic approach against breast cancer.

  14. Dub3 inhibition suppresses breast cancer invasion and metastasis by promoting Snail1 degradation

    PubMed Central

    Wu, Yadi; Wang, Yu; Lin, Yiwei; Liu, Yajuan; Wang, Yifan; Jia, Jianhang; Singh, Puja; Chi, Young-In; Wang, Chi; Dong, Chenfang; Li, Wei; Tao, Min; Napier, Dana; Shi, Qiuying; Deng, Jiong; Mark Evers, B; Zhou, Binhua P.

    2017-01-01

    Snail1, a key transcription factor of epithelial–mesenchymal transition (EMT), is subjected to ubiquitination and degradation, but the mechanism by which Snail1 is stabilized in tumours remains unclear. We identify Dub3 as a bona fide Snail1 deubiquitinase, which interacts with and stabilizes Snail1. Dub3 is overexpressed in breast cancer; knockdown of Dub3 resulted in Snail1 destabilization, suppressed EMT and decreased tumour cell migration, invasion, and metastasis. These effects are rescued by ectopic Snail1 expression. IL-6 also stabilizes Snail1 by inducing Dub3 expression, the specific inhibitor WP1130 binds to Dub3 and inhibits the Dub3-mediating Snail1 stabilization in vitro and in vivo. Our study reveals a critical Dub3–Snail1 signalling axis in EMT and metastasis, and provides an effective therapeutic approach against breast cancer. PMID:28198361

  15. Nicotinic acid inhibits glioma invasion by facilitating Snail1 degradation

    PubMed Central

    Li, Jiejing; Qu, Jiagui; Shi, Yu; Perfetto, Mark; Ping, Zhuxian; Christian, Laura; Niu, Hua; Mei, Shuting; Zhang, Qin; Yang, Xiangcai; Wei, Shuo

    2017-01-01

    Malignant glioma is a formidable disease that commonly leads to death, mainly due to the invasion of tumor cells into neighboring tissues. Therefore, inhibition of tumor cell invasion may provide an effective therapy for malignant glioma. Here we report that nicotinic acid (NA), an essential vitamin, inhibits glioma cell invasion in vitro and in vivo. Treatment of the U251 glioma cells with NA in vitro results in reduced invasion, which is accompanied by a loss of mesenchymal phenotype and an increase in cell-cell adhesion. At the molecular level, transcription of the adherens junction protein E-cadherin is upregulated, leading to accumulation of E-cadherin protein at the cell-cell boundary. This can be attributed to NA’s ability to facilitate the ubiquitination and degradation of Snail1, a transcription factor that represses E-cadherin expression. Similarly, NA transiently inhibits neural crest migration in Xenopus embryos in a Snail1-dependent manner, indicating that the mechanism of action for NA in cell migration is evolutionarily conserved. We further show that NA injection blocks the infiltration of tumor cells into the adjacent brain tissues and improves animal survival in a rat model of glioma. These results suggest that NA treatment may be developed into a potential therapy for malignant glioma. PMID:28256591

  16. Snail

    PubMed Central

    Wu, Yadi

    2010-01-01

    Snail has moved into the fast lane of development and cancer biology with the epithelial-mesenchymal transition (EMT) emerging as one of the hottest topics in medical science within the past few years. Snail not only acts primarily as a key inducer of EMT but also plays an important role in cell survival, immune regulation and stem cell biology. This review focuses on the regulation of Snail and discusses the EMT-dependent and -independent functions of Snail in development and disease. Understanding the regulation and functional roles of Snail will shed new light on the mechanism of tumor progression and the development of novel cancer therapies. PMID:20168078

  17. Effects of an invasive ant on land snails in the Ogasawara Islands.

    PubMed

    Uchida, Shota; Mori, Hideaki; Kojima, Tsubasa; Hayama, Kayo; Sakairi, Yuko; Chiba, Satoshi

    2016-12-01

    We investigated how Pheidole megacephala has affected endemic achatinellid snails because these snails are excellent indicators of the impact of ants and they have high conservation value in Ogasawara. In 2015 we surveyed the Minamizaki area of Hahajima Island of Ogasawara, designated a core zone of the World Heritage Site, for P. megacephala. In Minamizaki, we determined the distribution and density of achatinellid snails in 2015 and compared these data with their distribution and density in 2005. Land cover in the survey area was entirely forest. We also tested whether P. megacephala preyed on achatinellid snails in the laboratory. P. megacephala was present in the forested areas of Minamizaki. Achatinellid snails were absent in 19 of 39 sites where P. megacephala was present, whereas in other areas densities of the snails ranged from 2 to 228 individuals/site. In the laboratory, P. megacephala carried 6 of 7 achatinellid snails and a broken shell was found. Snail distribution and density comparisons and results of the feeding experiments suggest that the presence of P. megacephala has contributed to the decline of achatinellid snails in forests in the survey area. Yet, P. megacephala is not on the official list of invasive non-native species. Stakeholders using the list of invasive species to develop conservation programs should recognize that invasiveness of non-native species differs depending on the ecosystem and that official lists may not be complete.

  18. Invasiveness Does Not Predict Impact: Response of Native Land Snail Communities to Plant Invasions in Riparian Habitats

    PubMed Central

    Horáčková, Jitka; Juřičková, 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

  19. 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

  20. Large-scale facilitation of a sessile community by an invasive habitat-forming snail

    NASA Astrophysics Data System (ADS)

    Thyrring, Jakob; Thomsen, Mads Solgaard; Wernberg, Thomas

    2013-12-01

    We provide an example of extensive facilitation of a sessile community throughout an invaded estuary by the invasive snail Batillaria australis. We show that B. australis greatly increases a limiting resource (attachment space) to a community of sessile organisms and estimate that a large part of the invaded estuary now contain ca. 50 times more sessile individuals associated with the invader than all native snails combined. We argue that native snails are unlikely to have been dramatically reduced by the invader, and we therefore suggest that the shell-attached sessile community, as a functional group, has benefitted significantly from this invasion. These results expand the current understanding of how invaded marine systems respond to habitat-forming invaders.

  1. Effects of an exotic prey species on a native specialist: Eexample of the snail kite

    USGS Publications Warehouse

    Cattau, Christopher E.; Martin, J.; Kitchens, W.M.

    2010-01-01

    Despite acknowledging that exotic species can exhibit tremendous influence over native populations, few case studies have clearly demonstrated the effects of exotic prey species on native predators. We examined the effects of the recently introduced island apple snail (Pomacea insularum) on the foraging behavior and energetics of the endangered snail kite (Rostrhamus sociabilis plumbeus) in Florida. We conducted time-activity budgets: (i) on kites foraging for native Florida apple snails (Pomacea paludosa) in major wetland units within the kites' range that had not been invaded by the exotic island apple snail and (ii) on kites foraging for exotic apple snails in Lake Tohopekaliga, the only major wetland utilized by the snail kite that had suffered a serious invasion of P. insularum. When foraging for P. insularum, snail kites dropped a greater proportion of snails, and they experienced increased handling times and decreased consumption rates; however, kites foraging for P. insularum also spent a smaller proportion of the day in flight. Estimates of net daily energy balances between kites feeding on P. insularum versus P. paludosa were comparable for adults, but juveniles experienced energetic deficiencies when feeding on the exotic snail. Due to this discrepancy, we hypothesize that wetlands invaded by P. insularum, such as Lake Tohopekaliga, may function as ecological traps for the snail kite in Florida by attracting breeding adults but simultaneously depressing juvenile survival. This study highlights the conservation implications and importance of elucidating the effects that exotic species have on native specialists, especially those that are endangered, because subtle influences on behavior may have significant population consequences. ?? 2009 Elsevier Ltd.

  2. Effects of an exotic prey species on a native specialist: example of the snail kite

    USGS Publications Warehouse

    Cattau, Christopher E.; Martin, J.; Kitchens, Wiley M.

    2010-01-01

    Despite acknowledging that exotic species can exhibit tremendous influence over native populations, few case studies have clearly demonstrated the effects of exotic prey species on native predators. We examined the effects of the recently introduced island apple snail (Pomacea insularum) on the foraging behavior and energetics of the endangered snail kite (Rostrhamus sociabilis plumbeus) in Florida. We conducted time-activity budgets: (i) on kites foraging for native Florida apple snails (Pomacea paludosa) in major wetland units within the kites' range that had not been invaded by the exotic island apple snail and (ii) on kites foraging for exotic apple snails in Lake Tohopekaliga, the only major wetland utilized by the snail kite that had suffered a serious invasion of P. insularum. When foraging for P. insularum, snail kites dropped a greater proportion of snails, and they experienced increased handling times and decreased consumption rates; however, kites foraging for P. insularum also spent a smaller proportion of the day in flight. Estimates of net daily energy balances between kites feeding on P. insularum versus P. paludosa were comparable for adults, but juveniles experienced energetic deficiencies when feeding on the exotic snail. Due to this discrepancy, we hypothesize that wetlands invaded by P. insularum, such as Lake Tohopekaliga, may function as ecological traps for the snail kite in Florida by attracting breeding adults but simultaneously depressing juvenile survival. This study highlights the conservation implications and importance of elucidating the effects that exotic species have on native specialists, especially those that are endangered, because subtle influences on behavior may have significant population consequences.

  3. 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

    2014-03-07

    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 pCO₂, increases the susceptibility of native Olympia oysters to predation by invasive snails. Oysters raised under elevated pCO₂ experienced a 20% increase in drilling predation. When presented alongside control oysters in a choice experiment, 48% more high-CO₂ oysters were consumed. The invasive snails were tolerant of elevated CO₂ 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.

  4. 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.

  5. Experimental Test of Preferences for an Invasive Prey by an Endangered Predator: Implications for Conservation

    PubMed Central

    Wilcox, Rebecca C.

    2016-01-01

    Identifying impacts of exotic species on native populations is central to ecology and conservation. Although the effects of exotic predators on native prey have received much attention, the role of exotic prey on native predators is poorly understood. Determining if native predators actively prefer invasive prey over native prey has implications for interpreting invasion impacts, identifying the presence of evolutionary traps, and predator persistence. One of the world’s most invasive species, Pomacea maculata, has recently established in portions of the endangered Everglade snail kite’s (Rostrhamus sociabilis plumbeus) geographic range. Although these exotic snails could provide additional prey resources, they are typically much larger than the native snail, which can lead to lower foraging success and the potential for diminished energetic benefits in comparison to native snails. Nonetheless, snail kites frequently forage on exotic snails. We used choice experiments to evaluate snail kite foraging preference in relation to exotic species and snail size. We found that snail kites do not show a preference for native or exotic snails. Rather, snail kites generally showed a preference for medium-sized snails, the sizes reflective of large native snails. These results suggest that while snail kites frequently forage on exotic snails in the wild, this behavior is likely driven simply by the abundance of exotic snails rather than snail kites preferring exotics. This lack of preference offers insights to hypotheses regarding effects of exotic species, guidance regarding habitat and invasive species management, and illustrates how native-exotic relationships can be misleading in the absence of experimental tests of such interactions. PMID:27829031

  6. De novo assembly of the transcriptome of an invasive snail and its multiple ecological applications.

    PubMed

    Sun, J; Wang, M; Wang, H; Zhang, H; Zhang, X; Thiyagarajan, V; Qian, P Y; Qiu, J W

    2012-11-01

    Studying how invasive species respond to environmental stress at the molecular level can help us assess their impact and predict their range expansion. Development of markers of genetic polymorphism can help us reconstruct their invasive route. However, to conduct such studies requires the presence of substantial amount of genomic resources. This study aimed to generate and characterize genomic resources using high throughput transcriptome sequencing for Pomacea canaliculata, a nonmodel gastropod indigenous to Argentina that has invaded Asia, Hawaii and southern United States. De novo assembly of the transcriptome resulted in 128,436 unigenes with an average length of 419 bp (range: 150-8556 bp). Many of the unigenes (2439) contained transposable elements, showing the existence of a source of genetic variability in response to stressful conditions. A total of 3196 microsatellites were detected in the transcriptome; among 20 of the randomly tested microsatellites, 10 were validated to exhibit polymorphism. A total of 15,412 single-nucleotide polymorphisms (SNPs) were detected in the ORFs. LC-MS/MS analysis of the proteome of juveniles revealed 878 proteins, of which many are stress related. This study has demonstrated the great potential of high throughput DNA sequencing for rapid development of genomic resources for a nonmodel organism. Such resources can facilitate various molecular ecological studies, such as stress physiology and range expansion.

  7. Natural infection of the feline lungworm Aelurostrongylus abstrusus in the invasive snail Achatina fulica from Argentina.

    PubMed

    Valente, Romina; Diaz, Julia Ines; Salomón, Oscar Daniel; Navone, Graciela Teresa

    2017-02-15

    The giant African snail Achatina fulica is an invasive mollusk native to Africa, the first record in Argentina was in Puerto Iguazú, in northeastern Argentina in 2010. Recently it was reported in Corrientes Province. This snail can act as an intermediate host of Metastrongyloidea nematodes of importance in public health as: Angiostrongylus cantonensis, Angiostrongylus costaricensis and Angiostrongylus vasorum. Taking into account the presence of A. fulica in Argentina, the objectives of this study is to assess the presence of Metastrongyloidea nematodes in this mollusk species in Puerto Iguazú, Misiones, close to the international border with Brazil and Paraguay. A total of 451 samples were collected from February 2014 to November 2015. The snails were processed using a digestion technique to recover the parasites. A total of 206 nematodes larvae were founded in the digestion solution of 10 hosts (P=2%; MA=0.5; MI=21). Third larval stage (L3) nematodes identified as Aelurostrongylus abstrusus were founded parasitizing the snails. No other larval stage was observed. This species has veterinary importance because it causes 'aelurostrongilosis', also known as feline strongyloidosis. This study constitutes the first record of a Metastrongyloidea nematode in A. fulica in Argentina and also highlights the susceptibility of this mollusk as intermediate host of other helminthes of health importance. The present study suggests that there is a need to establish an epidemiological monitoring system in order to prevent the possible installation of an infected mollusks focus.

  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

  9. Sensitivity to dietary phosphorus limitation in native vs. invasive lineages of a New Zealand freshwater snail.

    PubMed

    Neiman, Maurine; Krist, Amy

    2016-10-01

    Why some species and lineages are more likely to be invasive than others is one of the most important unanswered questions in basic and applied biology. In particular, the relative contributions to the invasion process of factors like pre-adaptation to invasiveness in the native range, evolution post-colonization, and random vs. non-random sampling of colonist lineages remain unclear. We use a powerful common garden approach to address the potential for a role for sensitivity to nutrient limitation in determining the invasiveness of particular lineages of Potamopyrgus antipodarum, a New Zealand freshwater snail that has become globally invasive. We quantified specific growth rate (SGR), an important fitness-related trait in this species, under high phosphorus (P) vs. low-P conditions for a diverse set of native and invasive P. antipodarum. This experiment revealed that native-range P. antipodarum experience a more severe decline in SGR in low-P conditions relative to SGR in high-P conditions than their invasive range counterparts. Although these results suggest resilience to P limitation in invasive lineages, the absence of significant absolute differences in SGR between native and invasive lineages indicates that a straightforward connection between response to P limitation and invasiveness in P. antipodarum is unlikely. Regardless, our data demonstrate that invasive vs. native lineages of P. antipodarum exhibit consistently different responses to an important environmental variable that is rarely studied in the context of invasion success. Further studies directed at exploring and disentangling the roles of sampling effects, selection on preexisting variation, and evolution after colonization will be required to provide a comprehensive picture of the role (or lack thereof) of nutrient limitation in the global invasion of P. antipodarum, as well for as other invasive taxa.

  10. Adaptive responses and invasion: the role of plasticity and evolution in snail shell morphology.

    PubMed

    Kistner, Erica J; Dybdahl, Mark F

    2013-02-01

    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.

  11. Ocean acidification increases the vulnerability of native oysters to predation by invasive snails

    PubMed Central

    Sanford, Eric; Gaylord, Brian; Hettinger, Annaliese; Lenz, Elizabeth A.; Meyer, Kirstin; Hill, Tessa M.

    2014-01-01

    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 pCO2, increases the susceptibility of native Olympia oysters to predation by invasive snails. Oysters raised under elevated pCO2 experienced a 20% increase in drilling predation. When presented alongside control oysters in a choice experiment, 48% more high-CO2 oysters were consumed. The invasive snails were tolerant of elevated CO2 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

  12. 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

  13. Parasites reduce food web robustness because they are sensitive to secondary extinction as illustrated by an invasive estuarine snail.

    PubMed

    Lafferty, Kevin D; Kuris, Armand M

    2009-06-27

    A robust food web is one in which few secondary extinctions occur after removing species. We investigated how parasites affected the robustness of the Carpinteria Salt Marsh food web by conducting random species removals and a hypothetical, but plausible, species invasion. Parasites were much more likely than free-living species to suffer secondary extinctions following the removal of a free-living species from the food web. For this reason, the food web was less robust with the inclusion of parasites. Removal of the horn snail, Cerithidea californica, resulted in a disproportionate number of secondary parasite extinctions. The exotic Japanese mud snail, Batillaria attramentaria, is the ecological analogue of the native California horn snail and can completely replace it following invasion. Owing to the similarities between the two snail species, the invasion had no effect on predator-prey interactions. However, because the native snail is host for 17 host-specific parasites, and the invader is host to only one, comparison of a food web that includes parasites showed significant effects of invasion on the native community. The hypothetical invasion also significantly reduced the connectance of the web because the loss of 17 native trematode species eliminated many links.

  14. Parasites reduce food web robustness because they are sensitive to secondary extinction as illustrated by an invasive estuarine snail

    USGS Publications Warehouse

    Lafferty, Kevin D.; Kuris, Armand M.

    2009-01-01

    A robust food web is one in which few secondary extinctions occur after removing species. We investigated how parasites affected the robustness of the Carpinteria Salt Marsh food web by conducting random species removals and a hypothetical, but plausible, species invasion. Parasites were much more likely than free-living species to suffer secondary extinctions following the removal of a free-living species from the food web. For this reason, the food web was less robust with the inclusion of parasites. Removal of the horn snail, Cerithidea californica, resulted in a disproportionate number of secondary parasite extinctions. The exotic Japanese mud snail, Batillaria attramentaria, is the ecological analogue of the native California horn snail and can completely replace it following invasion. Owing to the similarities between the two snail species, the invasion had no effect on predator–prey interactions. However, because the native snail is host for 17 host-specific parasites, and the invader is host to only one, comparison of a food web that includes parasites showed significant effects of invasion on the native community. The hypothetical invasion also significantly reduced the connectance of the web because the loss of 17 native trematode species eliminated many links.

  15. Effect of Climate Change on Invasion Risk of Giant African Snail (Achatina fulica Férussac, 1821: Achatinidae) in India.

    PubMed

    Sarma, Roshmi Rekha; Munsi, Madhushree; Ananthram, Aravind Neelavara

    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.

  16. 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

  17. A prokineticin-like protein responds to immune challenges in the gastropod pest Pomacea canaliculata.

    PubMed

    Accorsi, Alice; Benatti, Stefania; Ross, Eric; Nasi, Milena; Malagoli, Davide

    2017-07-01

    The golden apple snail Pomacea canaliculata is an invasive pest originating from South America. It has already been found in Asia, the southern United States and more recently in the EU. Aiming to target the immune system of the snail as a way to control its spreading, we have developed organ-specific transcriptomes and looked for molecules controlling replication and differentiation of snail hemocytes. The prokineticin domain-containing protein Astakine 1 is the only cytokine known thus far capable of regulating invertebrate hematopoiesis, and we analyzed the transcriptomes looking for molecules containing a prokineticin domain. We have identified a prokineticin-like protein (PlP), that we called Pc-plp and we analyzed by real-time PCR (qPCR) its expression. In control snails, highest levels of Pc-plp were detected in the digestive gland, the ampulla (i.e., a hemocyte reservoir) and the pericardial fluid (i.e., the hematopoietic district). We tested Pc-plp expression after triggering hematopoiesis via multiple hemolymph withdrawals, or during bacterial challenge through LPS injection. In both cases a reduction of Pc-plp mRNA was observed. The multiple hemolymph withdrawals caused a significant decrease of Pc-plp mRNA in pericardial fluid and circulating hemocytes, while the LPS injection promoted the Pc-plp mRNA drop in anterior kidney, mantle and gills, organs that may act as immune barrier in molluscs. Our data indicate an important role for prokineticin domain-containing proteins as immunomodulators also in gastropods and their dynamic expression may serve as a biosensor to gauge the effectiveness of immunological interventions aimed at curtailing the spreading of the gastropod pest P. canaliculata.

  18. PDGF-D promotes dermal fibroblast invasion in 3-dimensional extracellular matrix via Snail-mediated MT1-MMP upregulation.

    PubMed

    Qin, Zhuo; Feng, Jinfa; Liu, Yusi; Deng, Li-Li; Lu, Changlian

    2016-01-01

    Increasing attention has been focused on the malignant tumor microenvironment, which plays important roles in tumor occurrence, progression and metastasis. Fibroblasts are recruited by platelet-derived growth factor (PDGFs) and invade the tumor microenvironment. In the PDGF family, PDGF-B has been reported to play an important role in the recruitment and invasion programs. However, whether PDGF-D plays a role in these programs remains unclear. We generated a recombinant plasmid expressing human PDGF-D and transfected the plasmid to dermal fibroblasts to examine the effects on cell invasive activities in 3D type I collagen gels. PDGF-D plasmid transfection enhanced fibroblast invasive activities both in invasive cell numbers and invasion depth in 3D collagen gels. These effects were blocked by Snail-specific siRNA transfection. PDGF-D transfection significantly induced Snail expression at both mRNA and protein levels. PDGF-D further upregulated MT1-MMP mRNA and protein expressions and this was inhibited when Snail was knocked down by siRNA. Both Snail and MT1-MMP expressions in fibroblasts and cellular invasive activities in 3D collagen induced by PDGF-D were inhibited by LY294002, SP600125, and U1026, the inhibitors of PI3K, JNK, and ERK1/2 signaling pathways, respectively. However, no effects were observed in response to the P38MAPK signaling pathway inhibitor SB203580. These effects of PDGF-D were confirmed by using the culture supernatants of the transfectants. Taken together, these data demonstrate that PDGF-D plays important roles in the recruitment and invasion programs of fibroblasts via the activation of PI3K, JNK and ERK1/2 signaling pathways, and upregulation of Snail and downstream effecter MT1-MMP. These findings indicate that PDGF-D is an important player in the tumor microenvironment for fibroblast recruitment.

  19. [Characteristics of Pomacea canaliculata reproduction under natural conditions].

    PubMed

    Liu, Jun; He, Yue-Jin; Tan, Ji-Cai; Xu, Cheng-Xiang; Zhong, Lang; Wang, Zhi-Gao; Liao, Qian-Guo

    2012-02-01

    Abstract: A three-year breeding experiment was conducted in a paddy field in Zixing City of Hunan Province, South-central China to study the characteristics of golden apple snail (Pomacea canaliculata) reproduction under natural conditions. Under the natural conditions in southern Hunan Province, the snails could approximately reproduce three generations per year. The average sexual maturity periods of the first, the second, and the third generation of the female snails were 59.3, 45.4 and 213.0 days, respectively, and those of the male snails were 4.3 days earlier than the females'. The natural sex ratio of the females to the males was 1.54:1. The average copulation duration was 19.2 hours, but spawning did not always occur after each time of copulation. The number of the egg masses produced by the females per month was significantly positively correlated with the mean monthly air temperature (r = 0.756) , while the average incubation duration of the egg masses was significantly negatively correlated with the daily air temperature (gamma = -0.726x + 23.064, r = -0.980). The average incubation time of the egg masses was 20.7 days, average incubation rate was 44.1%, and the average life expectancy of the female and male snails was 2.40 and 1.98 years, respectively. A female snail in its lifetime could averagely spawn 13764 eggs and reproduce 6070 young snails.

  20. Infection patterns in invasive and native snail hosts exposed to a parasite associated with waterfowl mortality in the upper Mississippi River, USA.

    PubMed

    Sandland, Gregory J; Gillis, Rick; Haro, Roger J; Peirce, James P

    2014-01-01

    Bithynia tentaculata is an aquatic invasive snail first detected in the upper Mississippi River (UMR) in 2002. The snail harbors a number of parasitic trematode species, including Sphaeridiotrema pseudoglobulus, that have been implicated in waterfowl mortality in the region. We assessed the capacity of S. pseudoglobulus cercariae to infect B. tentaculata and native snails found in the UMR. Four snail species (one invasive and three native) were individually exposed to S. pseudoglobulus larvae and all were successfully infected. A subsequent experiment examining infection patterns in invasive and native hosts exposed singly or in mixed treatments revealed no difference in parasite establishment among snail species. Our results add to our understanding of S. pseudoglobulus transmission and provide insight into processes underlying waterfowl disease in the UMR.

  1. Silencing Snail suppresses tumor cell proliferation and invasion by reversing epithelial-to-mesenchymal transition and arresting G2/M phase in non-small cell lung cancer.

    PubMed

    Yang, Xueying; Han, Mengmeng; Han, Haibo; Wang, Bingjing; Li, Sheng; Zhang, Zhiqian; Zhao, Wei

    2017-04-01

    Epithelial-to-mesenchymal transition (EMT) is essential for tumor invasion and metastasis. Snail has been proven to be a key regulator of EMT. Several studies have shown compelling evidence that Snail is also an important regulator of tumor growth and aggression; however, the role of Snail in the cell cycle has not been clarified. We decreased Snail expression by siRNA transfection and lentiviral‑mediated RNAi, to explore the effect of silencing Snail on the tumorigenicity and migration of lung carcinoma (lung cancer) cells. The results showed that silencing Snail conferred significant anti-proliferative activity and inhibited cell migration, tumor growth and metastasis both in vitro and in vivo. To understand the mechanism of these effects, we further investigated correlations among Snail expression, EMT and cell cycle. Significantly, Snail knockdown reversed EMT processes in lung cancer cells. Furthermore, the cyclin-dependent kinase inhibitor P21 was upregulated after silencing Snail. P21 upregulation manifested its tumor suppressor effects and arrested cells in the G2/M phase, not the G1/S phase following Snail depletion in lung cancer cells. These data suggest that silencing Snail decreases the malignant behaviors of lung cancer cells by reversing EMT processes and causing cell cycle defects.

  2. Development of ten microsatellite loci in the invasive giant African land snail, Achatina (=Lissachatina) fulica Bowdich, 1822

    USGS Publications Warehouse

    Morrison, Cheryl L.; Springmann, Marcus J.; Iwanowicz, Deborah D.; Wade, Christopher M.

    2015-01-01

    A suite of tetra-nucleotide microsatellite loci were developed for the invasive giant African land snail, Achatina (=Lissachatina) fulica Bowdich, 1822, from Ion Torrent next-generation sequencing data. Ten of the 96 primer sets tested amplified consistently in 30 snails from Miami, Florida, plus 12 individuals representative of their native East Africa, Indian and Pacific Ocean regions. The loci displayed moderate levels of allelic diversity (average 5.6 alleles/locus) and heterozygosity (average 42 %). Levels of genetic diversity were sufficient to produce unique multi-locus genotypes and detect phylogeographic structuring among regional samples. The invasive A. fulica can cause extensive damage to important food crops and natural resources, including native flora and fauna. The loci characterized here will be useful for determining the origins and tracking the spread of invasions, detecting fine-scale spatial structuring and estimating demographic parameters.

  3. 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

  4. Invasion Biology Meets Parasitology: A Case Study of Parasite Spill-Back with Egyptian Fasciola gigantica in the Invasive Snail Pseudosuccinea columella

    PubMed Central

    Grabner, Daniel S.; Mohamed, Faten A. M. M.; Nachev, Milen; Méabed, Eman M. H.; Sabry, Abdel Hameed A.; Sures, Bernd

    2014-01-01

    The liver fluke Fasciola gigantica is a trematode parasite of ruminants and humans that occurs naturally in Africa and Asia. Cases of human fascioliasis, attributable at least in part to F. gigantica, are significantly increasing in the last decades. The introduced snail species Galba truncatula was already identified to be an important intermediate host for this parasite and the efficient invader Pseudosuccinea columella is another suspect in this case. Therefore, we investigated snails collected in irrigation canals in Fayoum governorate in Egypt for prevalence of trematodes with focus on P. columella and its role for the transmission of F. gigantica. Species were identified morphologically and by partial sequencing of the cytochrome oxidase subunit I gene (COI). Among all 689 snails found at the 21 sampling sites, P. columella was the most abundant snail with 296 individuals (42.96%) and it was also the most dominant species at 10 sites. It was not found at 8 sites. Molecular detection by PCR and sequencing of the ITS1-5.8S-ITS2 region of the ribosomal DNA (rDNA) revealed infections with F. gigantica (3.38%), Echinostoma caproni (2.36%) and another echinostome (7.09%) that could not be identified further according to its sequence. No dependency of snail size and trematode infection was found. Both high abundance of P. columella in the Fayoum irrigation system and common infection with F. gigantica might be a case of parasite spill-back (increased prevalence in local final hosts due to highly susceptible introduced intermediate host species) from the introduced P. columella to the human population, explaining at least partly the observed increase of reported fascioliasis-cases in Egypt. Eichhornia crassipes, the invasive water hyacinth, which covers huge areas of the irrigation canals, offers safe refuges for the amphibious P. columella during molluscicide application. As a consequence, this snail dominates snail communities and efficiently transmits F. gigantica

  5. LIV-1 suppression inhibits HeLa cell invasion by targeting ERK1/2-Snail/Slug pathway

    SciTech Connect

    Zhao Le; Chen Wei; Taylor, Kathryn M.; Cai Bin; Li Xu

    2007-11-09

    It was reported that expression of the estrogen-regulated zinc transporter LIV-1 was particularly high in human cervical cancer cell line HeLa. This result prompted us to study the role that LIV-1 played in human cervical cancer. The results of real-time PCR showed that LIV-1 mRNA was significantly higher in cervical cancer in situ than in normal tissues. RNAi mediated suppression of LIV-1 in HeLa cells significantly inhibited cell proliferation, colony formation, migration, and invasive ability, but had no effect on cell apoptosis. Furthermore, LIV-1 suppression is accompanied by down-regulation of p44/42 MAPK, phospho-p44/42 MAPK, Snail and Slug expression levels. Hence, our data provide the first evidence that LIV-1 mRNA is overexpressed in cervical cancer in situ and is involved in invasion of cervical cancer cells through targeting MAPK-mediated Snail and Slug expression.

  6. An Easy Phylogenetically Informative Method to Trace the Globally Invasive Potamopyrgus Mud Snail from River's eDNA.

    PubMed

    Clusa, Laura; Ardura, Alba; Gower, Fiona; Miralles, Laura; Tsartsianidou, Valentina; Zaiko, Anastasija; Garcia-Vazquez, Eva

    2016-01-01

    Potamopyrgus antipodarum (New Zealand mud snail) is a prosobranch mollusk native to New Zealand with a wide invasive distribution range. Its non-indigenous populations are reported from Australia, Asia, Europe and North America. Being an extremely tolerant species, Potamopyrgus is capable to survive in a great range of salinity and temperature conditions, which explains its high invasiveness and successful spread outside the native range. Here we report the first finding of Potamopyrgus antipodarum in a basin of the Cantabrian corridor in North Iberia (Bay of Biscay, Spain). Two haplotypes already described in Europe were found in different sectors of River Nora (Nalon basin), suggesting the secondary introductions from earlier established invasive populations. To enhance the surveillance of the species and tracking its further spread in the region, we developed a specific set of primers for the genus Potamopyrgus that amplify a fragment of 16S rDNA. The sequences obtained from PCR on DNA extracted from tissue and water samples (environmental DNA, eDNA) were identical in each location, suggesting clonal reproduction of the introduced individuals. Multiple introduction events from different source populations were inferred from our sequence data. The eDNA tool developed here can serve for tracing New Zealand mud snail populations outside its native range, and for inventorying mud snail population assemblages in the native settings if high throughput sequencing methodologies are employed.

  7. An Easy Phylogenetically Informative Method to Trace the Globally Invasive Potamopyrgus Mud Snail from River’s eDNA

    PubMed Central

    Clusa, Laura; Ardura, Alba; Gower, Fiona; Miralles, Laura; Tsartsianidou, Valentina; Zaiko, Anastasija; Garcia-Vazquez, Eva

    2016-01-01

    Potamopyrgus antipodarum (New Zealand mud snail) is a prosobranch mollusk native to New Zealand with a wide invasive distribution range. Its non-indigenous populations are reported from Australia, Asia, Europe and North America. Being an extremely tolerant species, Potamopyrgus is capable to survive in a great range of salinity and temperature conditions, which explains its high invasiveness and successful spread outside the native range. Here we report the first finding of Potamopyrgus antipodarum in a basin of the Cantabrian corridor in North Iberia (Bay of Biscay, Spain). Two haplotypes already described in Europe were found in different sectors of River Nora (Nalon basin), suggesting the secondary introductions from earlier established invasive populations. To enhance the surveillance of the species and tracking its further spread in the region, we developed a specific set of primers for the genus Potamopyrgus that amplify a fragment of 16S rDNA. The sequences obtained from PCR on DNA extracted from tissue and water samples (environmental DNA, eDNA) were identical in each location, suggesting clonal reproduction of the introduced individuals. Multiple introduction events from different source populations were inferred from our sequence data. The eDNA tool developed here can serve for tracing New Zealand mud snail populations outside its native range, and for inventorying mud snail population assemblages in the native settings if high throughput sequencing methodologies are employed. PMID:27706172

  8. Functional links between Snail-1 and Cx43 account for the recruitment of Cx43-positive cells into the invasive front of prostate cancer.

    PubMed

    Ryszawy, Damian; Sarna, Michał; Rak, Monika; Szpak, Katarzyna; Kędracka-Krok, Sylwia; Michalik, Marta; Siedlar, Maciej; Zuba-Surma, Ewa; Burda, Kvetoslava; Korohoda, Włodzimierz; Madeja, Zbigniew; Czyż, Jarosław

    2014-09-01

    Suppressive function of connexin(Cx)43 in carcinogenesis was recently contested by reports that showed a multifaceted function of Cx43 in cancer progression. These studies did not attempt to model the dynamics of intratumoral heterogeneity involved in the metastatic cascade. An unorthodox look at the phenotypic heterogeneity of prostate cancer cells in vitro enabled us to identify links between Cx43 functions and Snail-1-regulated functional speciation of invasive cells. Incomplete Snail-1-dependent phenotypic shifts accounted for the formation of phenotypically stable subclones of AT-2 cells. These subclones showed diverse predilection for invasive behavior. High Snail-1 and Cx43 levels accompanied high motility and nanomechanical elasticity of the fibroblastoid AT-2_Fi2 subclone, which determined its considerable invasiveness. Transforming growth factor-β and ectopic Snail-1 overexpression induced invasiveness and Cx43 expression in epithelioid AT-2 subclones and DU-145 cells. Functional links between Snail-1 function and Cx43 expression were confirmed by Cx43 downregulation and phenotypic shifts in AT-2_Fi2, DU-145 and MAT-LyLu cells upon Snail-1 silencing. Corresponding morphological changes and Snail-1 downregulation were seen upon Cx43 silencing in AT-2_Fi2 cells. This indicates that feedback loops between both proteins regulate cell invasive behavior. We demonstrate that Cx43 may differentially predispose prostate cancer cells for invasion in a coupling-dependent and coupling-independent manner. When extrapolated to in vivo conditions, these data show the complexity of Cx43 functions during the metastatic cascade of prostate cancer. They may explain how Cx43 confers a selective advantage during cooperative invasion of clonally evolving, invasive prostate cancer cell subpopulations.

  9. 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

  10. Profound effects of population density on fitness-related traits in an invasive freshwater snail.

    PubMed

    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.

  11. Levels of infection with the lungworm Angiostrongylus cantonensis in terrestrial snails from Thailand, with Cryptozona siamensis as a new intermediate host.

    PubMed

    Vitta, A; Polsut, W; Fukruksa, C; Yimthin, T; Thanwisai, A; Dekumyoy, P

    2016-11-01

    Angiostrongylus cantonensis is primarily considered an emerging infectious agent of eosinophilic meningitis or meningoencephalitis with a worldwide distribution. Rodents and snails are important invasive hosts for transmission and expansion of A. cantonensis. The objective of this study was to investigate infection levels of A. cantonensis in snails, the most important natural intermediate host. Our study location was Mueang Kamphaeng Phet district, Kamphaeng Phet Province, and was undertaken between October and December 2012. A total of 2228 freshwater and terrestrial snails were collected, comprising 1119 Filopaludina spp., 409 Pomacea caniculata, 275 Achatina fulica and 425 Cryptozona siamensis. Angiostrongylus larvae were isolated by artificial digestion methods following Baermann's techniques. A low prevalence and intensity of A. cantonensis were observed in A. fulica, while higher numbers were found in C. siamensis. None of the Filopaludina spp. and Pomacea caniculata were infected with A. cantonensis. Molecular characterization was performed by analysing the 264 bp of cytochrome c oxidase subunit I (COI). Three COI sequences of Angiostrongylus were identical to A. cantonensis with 91-99% identity. Cryptozona siamensis has not previously been recorded as an intermediate host for A. cantonensis in Thailand. The infection of A. cantonensis identified in the natural intermediate hosts is new and important information to assist in the prevention and control of human angiostrongyliasis.

  12. 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.

  13. 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.

  14. Muscadine grape skin extract can antagonize Snail-cathepsin L-mediated invasion, migration and osteoclastogenesis in prostate and breast cancer cells

    PubMed Central

    Burton, Liza J.; Smith, Basil A.; Smith, Bethany N.; Loyd, Quentin; Nagappan, Peri; McKeithen, Danielle; Wilder, Catera L.; Platt, Manu O.; Hudson, Tamaro

    2015-01-01

    To develop new and effective chemopreventive agents against bone metastasis, we assessed the effects of muscadine grape skin extract (MSKE), whose main bioactive component is anthocyanin, on bone turnover, using prostate and breast cancer cell models overexpressing Snail transcription factor. MSKE has been shown previously to promote apoptosis in prostate cancer cells without affecting normal prostate epithelial cells. Snail is overexpressed in prostate and breast cancer, and is associated with increased invasion, migration and bone turnover/osteoclastogenesis. Cathepsin L (CatL) is a cysteine cathepsin protease that is overexpressed in cancer and involved in bone turnover. Snail overexpression in prostate (LNCaP, ARCaP-E) and breast (MCF-7) cancer cells led to increased CatL expression/activity and phosphorylated STAT-3 (pSTAT-3), compared to Neo vector controls, while the reverse was observed in C4-2 (the aggressive subline of LNCaP) cells with Snail knockdown. Moreover, CatL expression was higher in prostate and breast tumor tissue compared to normal tissue. MSKE decreased Snail and pSTAT3 expression, and abrogated Snail-mediated CatL activity, migration and invasion. Additionally, Snail overexpression promoted osteoclastogenesis, which was significantly inhibited by the MSKE as effectively as Z-FY-CHO, a CatL-specific inhibitor, or osteoprotegerin, a receptor activator of nuclear factor kappa B ligand (RANKL) antagonist. Overall, these novel findings suggest that Snail regulation of CatL may occur via STAT-3 signaling and can be antagonized by MSKE, leading to decreased cell invasion, migration and bone turnover. Therefore, inhibition using a natural product such as MSKE could potentially be a promising bioactive compound for bone metastatic cancer. PMID:26069256

  15. Metagenomic Analysis of the Microbiota from the Crop of an Invasive Snail Reveals a Rich Reservoir of Novel Genes

    PubMed Central

    Cardoso, Alexander M.; Cavalcante, Janaína J. V.; Cantão, Maurício E.; Thompson, Claudia E.; Flatschart, Roberto B.; Glogauer, Arnaldo; Scapin, Sandra M. N.; Sade, Youssef B.; Beltrão, Paulo J. M. S. I.; Gerber, Alexandra L.; Martins, Orlando B.; Garcia, Eloi S.; de Souza, Wanderley; Vasconcelos, Ana Tereza R.

    2012-01-01

    The shortage of petroleum reserves and the increase in CO2 emissions have raised global concerns and highlighted the importance of adopting sustainable energy sources. Second-generation ethanol made from lignocellulosic materials is considered to be one of the most promising fuels for vehicles. The giant snail Achatina fulica is an agricultural pest whose biotechnological potential has been largely untested. Here, the composition of the microbial population within the crop of this invasive land snail, as well as key genes involved in various biochemical pathways, have been explored for the first time. In a high-throughput approach, 318 Mbp of 454-Titanium shotgun metagenomic sequencing data were obtained. The predominant bacterial phylum found was Proteobacteria, followed by Bacteroidetes and Firmicutes. Viruses, Fungi, and Archaea were present to lesser extents. The functional analysis reveals a variety of microbial genes that could assist the host in the degradation of recalcitrant lignocellulose, detoxification of xenobiotics, and synthesis of essential amino acids and vitamins, contributing to the adaptability and wide-ranging diet of this snail. More than 2,700 genes encoding glycoside hydrolase (GH) domains and carbohydrate-binding modules were detected. When we compared GH profiles, we found an abundance of sequences coding for oligosaccharide-degrading enzymes (36%), very similar to those from wallabies and giant pandas, as well as many novel cellulase and hemicellulase coding sequences, which points to this model as a remarkable potential source of enzymes for the biofuel industry. Furthermore, this work is a major step toward the understanding of the unique genetic profile of the land snail holobiont. PMID:23133637

  16. Mitochondrial haplotypes and the New Zealand origin of clonal European Potamopyrgus, an invasive aquatic snail.

    PubMed

    Städler, T; Frye, M; Neiman, M; Lively, C M

    2005-07-01

    The small aquatic snail Potamopyrgus antipodarum is an important invading species in Europe, Australia and North America. European populations are generally believed to derive from accidental introductions from New Zealand, probably dating back to the mid-19th century. We have employed mitochondrial DNA sequences to test the proposed New Zealand origin of European Potamopyrgus, and to learn more about its genealogical history. Using a 481-bp region of the 16S ribosomal RNA gene, we identified 17 distinct haplotypes among 65 snails from New Zealand. In marked contrast, only two haplotypes were found across all European samples, which cover a large geographical area. Importantly, these two haplotypes are shared with snails from the North Island of New Zealand. Due to sampling limitations we cannot rule out a South Island origin for one of the haplotypes, but our results clearly demonstrate the New Zealand origin of European populations. The marked divergence among the two European haplotypes implies the successful colonization by two distinct mitochondrial lineages, which is consistent with previous data based on nuclear markers.

  17. Loop-mediated isothermal amplification: rapid detection of Angiostrongylus cantonensis infection in Pomacea canaliculata

    PubMed Central

    2011-01-01

    Background Angiostrongylus cantonensis is a zoonotic parasite that causes eosinophilic meningitis in humans. The most common source of infection with A. cantonensis is the consumption of raw or undercooked mollusks (e.g., snails and slugs) harbouring infectious third-stage larvae (L3). However, the parasite is difficult to identify in snails. The purpose of this study was to develop a quick, simple molecular method to survey for A. cantonensis in intermediate host snails. Findings We used a loop-mediated isothermal amplification (LAMP) assay, which was performed using Bst DNA polymerase. Reactions amplified the A. cantonensis 18S rRNA gene and demonstrated high sensitivity; as little as 1 fg of DNA was detected in the samples. Furthermore, no cross-reactivity was found with other parasites such as Toxoplasma gondii, Plasmodium falciparum, Schistosoma japonicum, Clonorchis sinensis, Paragonimus westermani and Anisakis. Pomacea canaliculata snails were exposed to A. cantonensis first-stage larvae (L1) in the laboratory, and L3 were observed in the snails thirty-five days after infection. All nine samples were positive as determined by the LAMP assay for A. cantonensis, which was identified as positive by using PCR and microscopy, this demonstrates that LAMP is sensitive and effective for diagnosis. Conclusions LAMP is an appropriate diagnostic method for the routine identification of A. cantonensis within its intermediate host snail P. canaliculata because of its simplicity, sensitivity, and specificity. It holds great promise as a useful monitoring tool for A. cantonensis in endemic regions. PMID:22023992

  18. Snail Snooping.

    ERIC Educational Resources Information Center

    Miller, Dorothy

    1993-01-01

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

  19. The anti-tumor activities of Neferine on cell invasion and oxaliplatin sensitivity regulated by EMT via Snail signaling in hepatocellular carcinoma

    PubMed Central

    Deng, Ganlu; Zeng, Shan; Ma, Junli; Zhang, Yan; Qu, Yanling; Han, Ying; Yin, Ling; Cai, Changjing; Guo, Cao; Shen, Hong

    2017-01-01

    Tumor invasion and chemotherapy resistance, which are associated with epithelial-mesenchymal transition (EMT), remain as major challenges in hepatocellular carcinoma (HCC) treatment. Neferine, a natural component of Nelumbo nucifera, have been proven the antitumor efficiency in cancer, but the effects of Neferine on HCC invasion and chemosensitivity need to be elucidated. Applying multiple assays of cell proliferation, flow cytometry, immunofluorescence staining, qRT-PCR, Western blot, fluorescence molecular tomography imaging, the influences of Neferine on EMT-regulated viability, apoptosis, invasion, and oxaliplatin (OXA) sensitivity were assessed in HCC cells of HepG2 and Bel-7402, as well as in xenograft animal models in vivo. Here, we reported that Neferine had no obvious effects on HCC cells proliferation, but significantly enhanced cytotoxicity and apoptosis caused by OXA in vitro and in vivo. Through an upregulation of E-cadherin and downregulation of Vimentin, Snail and N-cadherin, Neferine suppressed EMT-induced migration and invasion abilities of HCC cells. TGF-β1 cancelled the effects of Neferine on the migration and invasion of HCC cells. Snail overexpression or TGF-β1-induced EMT attenuated Neferine-mediated OXA sensitization in HCC. Together, our data suggest that Neferine enhances oxaliplatin sensitivity through an inhibition of EMT in HCC cells. Neferine may be used as an OXA sensitizer in HCC chemotherapy. PMID:28134289

  20. Spatial and temporal relationships between the invasive snail Bithynia tentaculata and submersed aquatic vegetation in Pool 8 of the Upper Mississippi River

    USGS Publications Warehouse

    Weeks, Alicia M.; DeJager, Nathan R.; Haro, Roger J.; Sandland, Greg J.

    2017-01-01

    Bithynia tentaculata is an invasive snail that was first reported in Lake Michigan in 1871 and has since spread throughout a number of freshwater systems of the USA. This invasion has been extremely problematic in the Upper Mississippi River as the snails serve as intermediate hosts for several trematode parasites that have been associated with waterfowl mortality in the region. This study was designed to assess the abundance and distribution of B. tentaculata relative to submersed aquatic vegetation as macrophytes provide important nesting and food resources for migrating waterfowl. Temporal changes in both vegetation and snail densities were compared between 2007 and 2015. Between these years, B. tentaculata densities have nearly quadrupled despite minor changes in vegetation abundance, distribution and composition. Understanding the spatial distribution of B. tentaculata in relation to other habitat features, including submersed vegetation, and quantifying any further changes in the abundance and distribution of B. tentaculata over time will be important for better identifying areas of risk for disease transmission to waterfowl.

  1. 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

  2. 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

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

    PubMed

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

    2010-01-01

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

  4. Well wrapped eggs: effects of egg shell structure on heat resistance and hatchling mass in the invasive land snail Cornu aspersum.

    PubMed

    Nicolai, Annegret; Vernon, Philippe; Lenz, Roman; Le Lannic, Joseph; Briand, Valérie; Charrier, Maryvonne

    2013-02-01

    In ectotherms, the temperature changes that accompany climate shifts, microhabitat changes, and species range extensions can have profound effects on the performance of organisms. The aim of this laboratory study on the terrestrial invasive gastropod Cornu aspersum was to investigate the effect of dietary calcium source on egg shell structure and heat resistance of eggs in two populations from different climatic regions of France (Western Atlantic and Mediterranean). To date no literature is known about heat stress in calcified ectothermic eggs while exposed to heat peaks using fluctuating thermal regimes and optimal humidity. In snails from the Mediterranean population fed exclusively with CaCO(3) from limestone we found the thinnest egg shells and the smallest hatchlings. Limestone represents the most accessible calcium source for snails, but is, however, responsible for thinner and more mineralized egg shells (higher ash content). Hence thicker egg shells result from a low mineralized mucopolysaccharide-glycoprotein matrix that could play a nutritional role for hatchlings. Exposed to heat peaks, eggs in both populations had lower incubation time variability at the detriment of hatching rate. This study highlights the need for functional studies in this invasive species to understand the effects on population dynamics of interacting biotic and abiotic environmental factors under climate and anthropic habitat changes.

  5. Transforming growth factor-α induces human ovarian cancer cell invasion by down-regulating E-cadherin in a Snail-independent manner.

    PubMed

    Qiu, Xin; Cheng, Jung-Chien; Klausen, Christian; Fan, Qianlan; Chang, Hsun-Ming; So, Wai-Kin; Leung, Peter C K

    2015-05-22

    Transforming growth factor-α (TGF-α), like epidermal growth factor (EGF) and amphiregulin (AREG) binds exclusively to EGF receptor (EGFR). We have previously demonstrated that EGF, AREG and TGF-α down-regulate E-cadherin and induce ovarian cancer cell invasion, though whether these ligands use the same molecular mediators remains unknown. We now show that, like EGF, TGF-α- and AREG-induced E-cadherin down-regulation involves both EGFR and HER2. However, in contrast to EGF and AREG, the transcription factor Snail is not required for TGF-α-induced E-cadherin down-regulation. This study shows that TGF-α uses common and divergent molecular mediators to regulate E-cadherin expression and cell invasion.

  6. Genetic Basis of Differential Heat Resistance between Two Species of Congeneric Freshwater Snails: Insights from Quantitative Proteomics and Base Substitution Rate Analysis.

    PubMed

    Mu, Huawei; Sun, Jin; Fang, Ling; Luan, Tiangang; Williams, Gray A; Cheung, Siu Gin; Wong, Chris K C; Qiu, Jian-Wen

    2015-10-02

    We compared the heat tolerance, proteomic responses to heat stress, and adaptive sequence divergence in the invasive snail Pomacea canaliculata and its noninvasive congener Pomacea diffusa. The LT50 of P. canaliculata was significantly higher than that of P. diffusa. More than 3350 proteins were identified from the hepatopancreas of the snails exposed to acute and chronic thermal stress using iTRAQ-coupled mass spectrometry. Acute exposure (3 h exposure at 37 °C with 25 °C as control) resulted in similar numbers (27 in P. canaliculata and 23 in P. diffusa) of differentially expressed proteins in the two species. Chronic exposure (3 weeks of exposure at 35 °C with 25 °C as control) caused differential expression of more proteins (58 in P. canaliculata and 118 in P. diffusa), with many of them related to restoration of damaged molecules, ubiquitinating dysfunctional molecules, and utilization of energy reserves in both species; but only in P. diffusa was there a shift from carbohydrate to lipid catabolism. Analysis of orthologous genes encoding the differentially expressed proteins revealed two genes having clear evidence of positive selection (Ka/Ks > 1) and seven candidates for more detailed analysis of positive selection (Ka/Ks between 0.5 and 1). These nine genes are related to energy metabolism, cellular oxidative homeostasis, signaling, and binding processes. Overall, the proteomic and base substitution rate analyses indicate genetic basis of differential resistance to heat stress between the two species, and such differences could affect their further range expansion in a warming climate.

  7. Integration of an invasive consumer into an estuarine food web: direct and indirect effects of the New Zealand mud snail.

    PubMed

    Brenneis, Valance E F; Sih, Andrew; de Rivera, Catherine E

    2011-09-01

    Introduced species interact both directly and indirectly with native species. We examine interactions between the introduced New Zealand mud snail (Potamopyrgus antipodarum) and native estuarine invertebrates and predators through experiments and field studies. A widely held management concern is that when P. antipodarum, which has low nutritional value, becomes abundant, it replaces nutritious prey in fish diets. We tested two key components of this view: (1) that fish consume, but get little direct nutritional value from P. antipodarum; and (2) that P. antipodarum has an indirect negative effect on fish by reducing the energy derived from native prey. We also examined predation by the native signal crayfish, Pacifastacus leniusculus. Laboratory feeding trials showed that both crayfish and fish consume P. antipodarum, a direct effect. Crayfish consumed and successfully digested higher numbers of snails than did fish [Pacific staghorn sculpin (Leptocottus armatus), three spine stickleback (Gasterosteus aculeatus), and juvenile starry flounder (Platicthys stellatus)]. P. antipodarum occurred at low frequencies in the stomachs of wild-caught fish. More interesting were the indirect effects of this invader, which ran counter to predictions. P. antipodarum presence was associated with no change or an increase in the amount of energy derived from native prey by predators. The presence of P. antipodarum also led to increased consumption of and preference for the native amphipod Americorophium salmonis over the native isopod Gnorimosphaeroma insulare. This is an example of short-term, asymmetric, apparent competition, in which the presence of one prey species (snails) increases predation on another prey species (the amphipod).

  8. Snail Trails

    ERIC Educational Resources Information Center

    Galus, Pamela

    2002-01-01

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

  9. 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.

  10. Epigenetic modification in neurons of the mollusc Pomacea canaliculata after immune challenge.

    PubMed

    Ottaviani, Enzo; Accorsi, Alice; Rigillo, Giovanna; Malagoli, Davide; Blom, Joan M C; Tascedda, Fabio

    2013-11-06

    In human and rodents, the transcriptional response of neurons to stress is related to epigenetic modifications of both DNA and histone proteins. To assess the suitability of simple invertebrate models in studying the basic mechanisms of stress-related epigenetic modifications, we analyzed epigenetic modifications in neurons of the freshwater snail Pomacea canaliculata after the injection of Escherichia coli-derived lipopolysaccharide (LPS). The phospho-acetylation of histone H3, together with the induction of stress-related factors, c-Fos and HSP70, were evaluated in large and small neurons of the pedal ganglia of sham- and LPS-injected snails. Immunocytochemical investigations showed that after LPS injection, the immunopositivity towards phospho (Ser10)-acetyl (Lys14)-histone H3 and c-Fos increases in the nuclei of small gangliar neurons. Western blot analysis confirmed a significant increase of phospho (Ser10)-acetyl (Lys14)-histone H3 in nuclear extracts from 2h LPS-injected animals. c-Fos protein levels were significantly augmented 6h after LPS injection. Immunocytochemistry and western blot indicated that no changes occurred in HSP70 distribution and protein levels. To our knowledge this is the first demonstration of epigenetic changes in molluscan neurons after an immune challenge and indicate the gastropod P. canaliculata as a suitable model for evolutionary and translational studies on stress-related epigenetic modifications.

  11. Non-native molluscan colonizers on deliberately placed shipwrecks in the Florida Keys, with description of a new species of potentially invasive worm-snail (Gastropoda: Vermetidae).

    PubMed

    Bieler, Rüdiger; Granados-Cifuentes, Camila; Rawlings, Timothy A; Sierwald, Petra; Collins, Timothy M

    2017-01-01

    Artificial reefs created by deliberately sinking ships off the coast of the Florida Keys island chain are providing new habitat for marine invertebrates. This newly developing fouling community includes the previously reported invasive orange tube coral Tubastraea coccinea and the non-native giant foam oyster Hyotissa hyotis. New SCUBA-based surveys involving five shipwrecks spanning the upper, middle, and lower Florida Keys, show T. coccinea now also established in the lower Keys and H. hyotis likewise extending to new sites. Two additional mollusks found on the artificial reefs, the amathinid gastropod Cyclothyca pacei and gryphaeid oyster Hyotissa mcgintyi, the latter also common in the natural reef areas, are discussed as potentially non-native. A new species of sessile, suspension-feeding, worm-snail, Thylacodes vandyensis Bieler, Rawlings & Collins n. sp. (Vermetidae), is described from the wreck of the USNS Vandenberg off Key West and discussed as potentially invasive. This new species is compared morphologically and by DNA barcode markers to other known members of the genus, and may be a recent arrival from the Pacific Ocean. Thylacodes vandyensis is polychromatic, with individuals varying in both overall head-foot coloration and mantle margin color pattern. Females brood stalked egg capsules attached to their shell within the confines of their mantle cavity, and give rise to crawl-away juveniles. Such direct-developing species have the demonstrated capacity for colonizing habitats isolated far from their native ranges and establishing rapidly growing founder populations. Vermetid gastropods are common components of the marine fouling community in warm temperate and tropical waters and, as such, have been tagged as potentially invasive or with a high potential to be invasive in the Pacific Ocean. As vermetids can influence coral growth/composition in the Pacific and have been reported serving as intermediate hosts for blood flukes of loggerhead turtles

  12. Non-native molluscan colonizers on deliberately placed shipwrecks in the Florida Keys, with description of a new species of potentially invasive worm-snail (Gastropoda: Vermetidae)

    PubMed Central

    Granados-Cifuentes, Camila; Rawlings, Timothy A.; Sierwald, Petra; Collins, Timothy M.

    2017-01-01

    Artificial reefs created by deliberately sinking ships off the coast of the Florida Keys island chain are providing new habitat for marine invertebrates. This newly developing fouling community includes the previously reported invasive orange tube coral Tubastraea coccinea and the non-native giant foam oyster Hyotissa hyotis. New SCUBA-based surveys involving five shipwrecks spanning the upper, middle, and lower Florida Keys, show T. coccinea now also established in the lower Keys and H. hyotis likewise extending to new sites. Two additional mollusks found on the artificial reefs, the amathinid gastropod Cyclothyca pacei and gryphaeid oyster Hyotissa mcgintyi, the latter also common in the natural reef areas, are discussed as potentially non-native. A new species of sessile, suspension-feeding, worm-snail, Thylacodes vandyensis Bieler, Rawlings & Collins n. sp. (Vermetidae), is described from the wreck of the USNS Vandenberg off Key West and discussed as potentially invasive. This new species is compared morphologically and by DNA barcode markers to other known members of the genus, and may be a recent arrival from the Pacific Ocean. Thylacodes vandyensis is polychromatic, with individuals varying in both overall head-foot coloration and mantle margin color pattern. Females brood stalked egg capsules attached to their shell within the confines of their mantle cavity, and give rise to crawl-away juveniles. Such direct-developing species have the demonstrated capacity for colonizing habitats isolated far from their native ranges and establishing rapidly growing founder populations. Vermetid gastropods are common components of the marine fouling community in warm temperate and tropical waters and, as such, have been tagged as potentially invasive or with a high potential to be invasive in the Pacific Ocean. As vermetids can influence coral growth/composition in the Pacific and have been reported serving as intermediate hosts for blood flukes of loggerhead turtles

  13. [The interplay between schistosome and its snail host: a review].

    PubMed

    Wang, Fei; Dai, Jian-Rong

    2012-12-01

    As the only intermediate host of Schistosoma japonicum, the control of Oncomelania snails serves as a major part in schistosomiasis control. This review mainly demonstrates the following aspects: the invasion of schistosome miracidium into snails, the mechanism of resistance to miracidia, and the factors influencing this process. With a view to explore the methods of interrupting every phase during miracidium infection, this article focuses on the possibility for safeguarding human health through protecting snails, namely, achieving snails harmlessness.

  14. Heterogeneous evolution of microsatellites revealed by reconstruction of recent mutation history in an invasive apomictic snail, Potamopyrgus antipodarum.

    PubMed

    Weetman, David; Hauser, Lorenz; Carvalho, Gary R

    2006-05-01

    Heterogeneous patterns of microsatellite evolution present a major challenge for the development of mutation models, and an improved understanding of the determinants of variation in mutation rates and patterns among loci, alleles and taxa is required. A 19th Century bottleneck associated with the introduction of clones of the snail Potamopyrgus antipodarum to Britain presented an opportunity to reconstruct recent microsatellite evolution within the most common apomictic lineage. There was significant variation in both the number and step size of mutations among the seven loci studied. Patterns of mutability were consistent with higher mutation rates for di- than trinucleotides and for longer alleles at a locus. Mutation size was influenced in a more complex way, decreasing with relative allele length much more strongly for tri-, than dinucleotides. We found support for this latter, highly novel result in the literature via reanalysis of data in a recent genome-scan study of human microsatellites, which showed a similarly disparate pattern of length-dependence between di- and trinucleotides. In spite of the apomictic form of reproduction and an unusually strong excess of microsatellite contractions in P. antipodarum, there were notable similarities with mutation processes of human microsatellites, supporting the wider taxonomic generality of such evolutionary mechanisms.

  15. Reconstruction of microsatellite mutation history reveals a strong and consistent deletion bias in invasive clonal snails, Potamopyrgus antipodarum.

    PubMed

    Weetman, David; Hauser, Lorenz; Carvalho, Gary R

    2002-10-01

    Direct observations of mutations and comparative analyses suggest that nuclear microsatellites show a tendency to expand, with reports of deletion biases limited to very long alleles or a few loci in multilocus studies. Here we investigate microsatellite evolution in clonal snails, Potamopyrgus antipodarum, since their introduction to Britain in the 19th century, using an analysis based on minimum spanning networks of multilocus microsatellite genotypes. British populations consist of a small number of highly distinct genotype groups with very few outlying genotypes, suggesting clonal lineages containing minor variation generated by mutation. Network patterns suggest that a single introduced genotype was the ancestor of all extant variation and also provide support for wholly apomictic reproduction within the most common clonal lineage (group A). Microsatellites within group A showed a strong tendency to delete repeats, with an overall bias exceeding 88%, irrespective of the exact method used to infer mutations. This highly unusual pattern of deletion bias is consistent across populations and loci and is unrelated to allele size. We suggest that for persistence of microsatellites in this clone, some change in the mutation mechanism must have occurred in relatively recent evolutionary time. Possible causes of such a change in mechanism are discussed.

  16. Exploring the temporal effects of seasonal water availability on the snail kite of Florida: Part III

    USGS Publications Warehouse

    Mooij, Wolf M.; Martin, Julien; Kitchens, Wiley M.; DeAngelis, Donald L.; Bissonette, John A.; Storch, Ilse

    2007-01-01

    The Florida snail kite (Rostrhamus sociabilis) is an endangered raptor that occurs as an isolated population, currently of about 2,000 birds, in the wetlands of southern and central Florida, USA. Its exclusive prey species, the apple snail (Pomacea paludosa) is strongly influenced by seasonal changes in water abundance. Droughts during the snail kite breeding season have a direct negative effect on snail kite survival and reproduction, but droughts are also needed to maintain aquatic vegetation types favorable to snail kite foraging for snails. We used a spatially explicit matrix model to explore the effects of temporal variation in water levels on the viability of the snail kite population under different temporal drought regimes in its wetland breeding habitat. We focused on three aspects of variations in water levels that were likely to affect kites: (1) drought frequency; (2) drought duration; and (3) drought timing within the year. We modeled a 31-year historical scenario using four different scenarios in which the average water level was maintained constant, but the amplitude of water level fluctuations was modified. Our results reveal the complexity of the effects of temporal variation in water levels on snail kite population dynamics. Management implications of these results are discussed. In particular, management decisions should not be based on annual mean water levels alone, but must consider the intra-annual variability.

  17. Variation in Thermal Sensitivity and Thermal Tolerances in an Invasive Species across a Climatic Gradient: Lessons from the Land Snail Cornu aspersum

    PubMed Central

    Gaitán-Espitia, Juan Diego; Belén Arias, María; Lardies, Marco A.; Nespolo, Roberto F.

    2013-01-01

    The ability of organisms to perform at different temperatures could be described by a continuous nonlinear reaction norm (i.e., thermal performance curve, TPC), in which the phenotypic trait value varies as a function of temperature. Almost any shift in the parameters of this performance curve could highlight the direct effect of temperature on organism fitness, providing a powerful framework for testing thermal adaptation hypotheses. Inter-and intraspecific differences in this performance curve are also reflected in thermal tolerances limits (e.g., critical and lethal limits), influencing the biogeographic patterns of species’ distribution. Within this context, here we investigated the intraspecific variation in thermal sensitivities and thermal tolerances in three populations of the invasive snail Cornu aspersum across a geographical gradient, characterized by different climatic conditions. Thus, we examined population differentiation in the TPCs, thermal-coma recovery times, expression of heat-shock proteins and standard metabolic rate (i.e., energetic costs of physiological differentiation). We tested two competing hypotheses regarding thermal adaptation (the “hotter is better” and the generalist-specialist trade-offs). Our results show that the differences in thermal sensitivity among populations of C. aspersum follow a latitudinal pattern, which is likely the result of a combination of thermodynamic constraints (“hotter is better”) and thermal adaptations to their local environments (generalist-specialist trade-offs). This finding is also consistent with some thermal tolerance indices such as the Heat-Shock Protein Response and the recovery time from chill-coma. However, mixed responses in the evaluated traits suggest that thermal adaptation in this species is not complete, as we were not able to detect any differences in neither energetic costs of physiological differentiation among populations, nor in the heat-coma recovery. PMID:23940617

  18. Applying weight gain in Pomacea lineata (SPIX 1824) (Mollusca: Prosobranchia) as a measure of herbicide toxicity.

    PubMed

    Coler, R A; Coler, R R; Felizardo, E K G; Watanabe, T

    2005-11-01

    Pomacea lineata, an extremely ubiquitous snail and pest to rice farmers throughout Asia, holds promise as a valuable resource for monitoring water quality in northeast Brazil. In this paper, we present data demonstrating the rate of weight gain in P. lineata neonates as a consistent measure of the stress imposed by sublethal concentrations of the herbicides Paraquat and Round-up. Our secondary agenda is to demonstrate the feasibility of incorporating bioassay into the standard municipal and state procedure of monitoring water quality. Growth data to assess chronic toxicity were generated in experiments of four and four, eight, twelve and sixteen days for Paraquat and Round-up, respectively. We estimated a 96 h no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) for Paraquat of 0.12 and 0.25 mg/L. The 96 h Round-up data yielded NOEC and LOEC values, respectively, of 0.25 and 0.5 mg/L. All concentrations of Round-up tested for the 192 h exposure yielded significantly lower growth than the control. Consequently, no NOEC could be derived. The LOEC was < 0.12 mg/L. Furthermore, there was no mortality during the test. At the lowest concentrations of Paraquat tested (0.005 mg/L) there was a significant increase in growth compared with the controls, suggesting a hormetic effect.

  19. Life History Variation in Invading Applesnails (Pomacea canaliculata) May Pose Ecological Threats to Wetlands

    NASA Astrophysics Data System (ADS)

    Marfurt, R. K.; Boland, B. B.; Burks, R. L.

    2005-05-01

    In native habitats, channeled applesnails (Pomacea canaliculata) graze periphyton. However, casual observations from introduced populations suggest these invaders show variation in feeding ecology, predator response and life history strategies. Attempts to predict this consumer influence on ecosystem function suffer from a lack of basic data. We tested how salinity affected snail mortality. Both adults and hatchlings tolerated salinity levels up to 8 ppt. Adult feeding on lettuce increased significantly at 8 ppt compared to 0 ppt (p = 0.002), while hatchling consumption of algae did not vary (p = 0.284). To see how these consumers responded to predators from the invaded ecosystem, we tested behavioural responses to predatory cues from fish, turtles, crayfish and adult applesnails. Results indicated that fish and crayfish prompted similar predator-avoidance behaviors in hatchlings (p's < 0.05) and that hatchling response changed over time. Consumption rates of juvenile redear sunfish did not vary (x2, p > 0.05) between native (ramshorn) and exotic applesnails, whereas adult fish consumed more applesnails (x2, p < 0.001). Our current efforts focus on examining if predator presence or macrophyte choice alters applesnail feeding rates. Research providing insight into the basic ecology of applesnails can foster management efforts at the ecosystem scale.

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

    PubMed

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

    2001-07-01

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

  1. The faucet snail (Bithynia tentaculata) invades the St. Louis River Estuary

    EPA Science Inventory

    The European-origin faucet snail (Bithynia tentaculata) now numbers among the aquatic invasive species present in the St. Louis River Estuary. This snail has been in the lower Great Lakes since the early 20th century but is new to the Lake Superior basin. We found faucet snails...

  2. The occurrence of the rat lungworm, Angiostrongylus cantonensis, in nonindigenous snails in the Gulf of Mexico region of the United States

    USGS Publications Warehouse

    Teem, John L.; Qvarnstrom, Yvonne; Bishop, Henry S.; da Silva, Alexandre J.; Carter, Jacoby; White-McLean, Jodi; Smith, Trevor

    2013-01-01

    Nonindigenous apple snails, Pomacea maculata (formerly Pomacea insularum), are currently spreading rapidly through the southeastern United States. This mollusk serves as an intermediate host of the rat lungworm parasite (Angiostrongylus cantonensis), which can cause eosinophilic meningitis in humans who consume infected mollusks. A PCR-based detection assay was used to test nonindigenous apple snails for the rat lungworm parasite in Louisiana, Texas, Mississippi, and Florida. Only apple snails obtained from the New Orleans, Louisiana, area tested positive for the parasite. These results provide the first evidence that Angiostrongylus cantonensis does occur in nonindigenous apple snails in the southeastern United States. Additionally, Angiostrongylus cantonensis was identified in the terrestrial species Achatina fulica in Miami, Florida, indicating that rat lungworm is now established in Florida as well as Louisiana. Although the study suggests that the rat lungworm is not widespread in the Gulf States region, the infected snail population could still pose a risk to human health and facilitate the spread of the parasite to new areas.

  3. The Occurrence of the Rat Lungworm, Angiostrongylus cantonensis, in Nonindigenous Snails in the Gulf of Mexico Region of the United States

    PubMed Central

    Qvarnstrom, Yvonne; Bishop, Henry S; da Silva, Alexandre J; Carter, Jacoby; White-Mclean, Jodi; Smith, Trevor

    2013-01-01

    Nonindigenous apple snails, Pomacea maculata (formerly Pomacea insularum), are currently spreading rapidly through the southeastern United States. This mollusk serves as an intermediate host of the rat lungworm parasite (Angiostrongylus cantonensis), which can cause eosinophilic meningitis in humans who consume infected mollusks. A PCR-based detection assay was used to test nonindigenous apple snails for the rat lungworm parasite in Louisiana, Texas, Mississippi, and Florida. Only apple snails obtained from the New Orleans, Louisiana, area tested positive for the parasite. These results provide the first evidence that Angiostrongylus cantonensis does occur in nonindigenous apple snails in the southeastern United States. Additionally, Angiostrongylus cantonensis was identified in the terrestrial species Achatina fulica in Miami, Florida, indicating that rat lungworm is now established in Florida as well as Louisiana. Although the study suggests that the rat lungworm is not widespread in the Gulf States region, the infected snail population could still pose a risk to human health and facilitate the spread of the parasite to new areas. PMID:23901374

  4. The feeding habits of the snail kite in Florida, USA

    USGS Publications Warehouse

    Sykes, P.W.

    1987-01-01

    The feeding habits of the Snail Kite (Rostrhamus sociabilis) were observed intermittently from 1967-1980 in Florida, USA. Approximately 97% of all observed foraging bouts were over marshes having sparse emergent vegetation. The visually-hunting kite was unable to forage over floating mats of exotic water hyacinth (Eichhornia crassipes). Male kites had shorter hunting bouts than females. For still-hunting, the birds' perches ranged from 0.15-4.6 m high and captures occurred an average of 5.8 m from perches. Females were significantly more successful (70%) for course-hunting than males (48%), but I found no difference for still-hunting. Birds tended to forage throughout the day, except for occasional inactive periods by some individuals during midday. On cooler days, foraging commenced slightly later in the morning than on warmer days. Kites probably capture freshwater apple snails (Pomacea paludosa) as deep as 16 cm. Capture rates for adults generally ranged from 1.7-3.4 snails per hour. Kites usually foraged over a common hunting area, and defense of foraging sites was rare. Handling of snails, from the kite's arrival at the feeding perch unit consumption, averaged 2.7 min, with no significant difference between sexes. However, adult females were more efficient at the extraction portion of this process than were adult males. Snails were usually extracted before being brought to the nest, except in the latter part of the nestling period when some snails were extracted at or near the nest and some were brought intact. Adults feed small chicks bill to bill, and both parents generally shared equally in care of the young, except at two nests where the females did 67% or more of the feeding. Mean length of snails taken by kites was 42.8 mm (range 25.2-71.3 n=697) and mean diameter was 45.8 mm (range 27.4-82.4, n=697). The most common size classes tkaen were 30-60 mm in length and diameter. Nutritional and gross energy values were determined for apple snails. Female

  5. 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.

  6. Isolation and characterization of a novel perivitellin from the eggs of Pomacea scalaris (Mollusca, Ampullariidae).

    PubMed

    Ituarte, S; Dreon, M S; Ceolín, M; Heras, H

    2008-09-01

    Perivitellins are important components of the perivitelline fluid (PVF) that surrounds gastropod embryos. The glyco-lipo-carotenoprotein ovorubin (OR) from eggs of the snail Pomacea canaliculata has been the most studied to date. Here we report the characterization of scalarin (SC), a glyco-lipo-carotenoprotein from the PVF of P. scalaris. SC was purified by ultracentrifugation and exclusion chromatography. It is the major egg protein, representing 64% of the total soluble protein. The particle has a hydration density of 1.26 g/ml, an apparent molecular mass of 380 kDa and it is an elongated compact protein as estimated by small angle X-ray scattering (SAXS). It is composed of three subunits of ca. 35, 28, and 24 kDa noncovalently bonded. SC is highly glycosylated (carbohydrate content 20.1%, by wt.), with a low lipid content (0.7%), being esterified sterols, pigments and polar lipids the most abundant lipid classes. HPTLC and spectrophotometric analysis of the carotenoid fraction revealed the presence of free astaxanthin (ASX; 62.0%), and an unidentified carotenoid (38.0%). The carotenoid-apoprotein interaction was studied by spectrophotometry. Carotenoids do not seem to affect the structural characteristics of the oligomer. However, the carotenoid-protein association protected ASX against oxidation. The cross-reactivity between SC and perivitellins of P. canaliculata was tested using polyclonal antibodies (PAb) against SC, OR, and perivitellin PV2. The PAbs failed to cross-react with any egg proteins of either the same or other species. SC, among other functional similarities with OR, would be an antioxidant carrier, protecting at the same time carotenoids from oxidation in the perivitellin fluid of the egg.

  7. Fungal farming in a snail

    PubMed Central

    Silliman, Brian R.; Newell, Steven Y.

    2003-01-01

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

  8. MicroRNA-106b-25 cluster targets β-TRCP2, increases the expression of Snail and enhances cell migration and invasion in H1299 (non small cell lung cancer) cells.

    PubMed

    Savita, Udainiya; Karunagaran, Devarajan

    2013-05-17

    Lung cancer causes high mortality without a declining trend and non small cell lung cancer represents 85% of all pulmonary carcinomas. MicroRNAs (miRNAs) serve as fine regulators of proliferation, migration, invasion/metastasis and angiogenesis of normal and cancer cells. Using TargetScan6.2, we predicted that the ubiquitin ligase, β-TRCP2, could be a target for two of the constituent miRNAs of the miR-106b-25 cluster (miR-106b and miR-93). We generated a stable clone of miR-106b-25 cluster (CL) or the empty vector (EV) in H1299 (non small cell lung cancer) cells. The expression of β-TRCP2 mRNA was significantly lower in CL than that in EV cells. Transient expression of miR-93 but not antimiR-93 decreased the expression of β-TRCP2 mRNA in H1299 cells. β-TRCP2-3'UTR reporter assay revealed that its activity in CL cells was only 60% of that in EV cells. Snail protein expression was higher in CL than that in EV cells and H1299 cells exhibited an increase in the expression of Snail upon transient transfection with miR-93. miR-106b-25 cluster-induced migration of CL measured by scratch assay was more than that in EV cells and no significant difference in migration was observed between antimiR-93-transfected H1299 cells and the corresponding control-oligo-transfected cells. miR-106b-25 cluster-induced migration of CL cells was again confirmed in a Boyden chamber assay without the matrigel. CL cells were more invasive than EV cells when assessed using Boyden chambers with matrigel but there were no significant changes in the cell viabilities between EV and CL cells. Colony formation assay revealed that the CL cells formed more number of colonies than EV cells but they were smaller in size than those formed by EV cells. The supernatant from CL cells was more effective than that from EV cells in inducing tube formation in endothelial cells. Taken together, our data indicate that miR-106b-25 cluster may play an important role in the metastasis of human non-small cell

  9. MicroRNA-106b-25 cluster targets β-TRCP2, increases the expression of Snail and enhances cell migration and invasion in H1299 (non small cell lung cancer) cells

    SciTech Connect

    Savita, Udainiya; Karunagaran, Devarajan

    2013-05-17

    Highlights: •miR-106b-25 cluster directly targets the 3′UTR of the β-TRCP2 transcript. •β-TRCP2 mRNA was lower in H1299 cells stably expressing miR-106b-25 cluster. •miR-106b-25 cluster increased the expression of Snail. •miR-106b-25 cluster promoted the migration, colony formation and invasion. •miR-106b-25 cluster enhanced endothelial tube formation. -- Abstract: Lung cancer causes high mortality without a declining trend and non small cell lung cancer represents 85% of all pulmonary carcinomas. MicroRNAs (miRNAs) serve as fine regulators of proliferation, migration, invasion/metastasis and angiogenesis of normal and cancer cells. Using TargetScan6.2, we predicted that the ubiquitin ligase, β-TRCP2, could be a target for two of the constituent miRNAs of the miR-106b-25 cluster (miR-106b and miR-93). We generated a stable clone of miR-106b-25 cluster (CL) or the empty vector (EV) in H1299 (non small cell lung cancer) cells. The expression of β-TRCP2 mRNA was significantly lower in CL than that in EV cells. Transient expression of miR-93 but not antimiR-93 decreased the expression of β-TRCP2 mRNA in H1299 cells. β-TRCP2-3′UTR reporter assay revealed that its activity in CL cells was only 60% of that in EV cells. Snail protein expression was higher in CL than that in EV cells and H1299 cells exhibited an increase in the expression of Snail upon transient transfection with miR-93. miR-106b-25 cluster-induced migration of CL measured by scratch assay was more than that in EV cells and no significant difference in migration was observed between antimiR-93-transfected H1299 cells and the corresponding control-oligo-transfected cells. miR-106b-25 cluster-induced migration of CL cells was again confirmed in a Boyden chamber assay without the matrigel. CL cells were more invasive than EV cells when assessed using Boyden chambers with matrigel but there were no significant changes in the cell viabilities between EV and CL cells. Colony formation assay

  10. Molluscicidal activity of cardiac glycosides from Nerium indicum against Pomacea canaliculata and its implications for the mechanisms of toxicity.

    PubMed

    Dai, Lingpeng; Wang, Wanxian; Dong, Xinjiao; Hu, Renyong; Nan, Xuyang

    2011-09-01

    Cardiac glycosides from fresh leaves of Nerium indicum were evaluated for its molluscicidal activity against Pomacea canaliculata (golden apple snail: GAS) under laboratory conditions. The results showed that LC(50) value of cardiac glycosides against GAS was time dependent and the LC(50) value at 96 h was as low as 3.71 mg/L, which was comparable with that of metaldehyde at 72 h (3.88 mg/L). These results indicate that cardiac glycosides could be an effective molluscicide against GAS. The toxicological mechanism of cardiac glucosides on GAS was also evaluated through changes of selected biochemical parameters, including cholinesterase (ChE) and esterase (EST) activities, glycogen and protein contents in hepatopancreas tissues of GAS. Exposure to sublethal concentrations of cardiac glycosides, GAS showed lower activities of EST isozyme in the later stages of the exposure period as well as drastically decreased glycogen content, although total protein content was not affected at the end of 24 and 48 h followed by a significant depletion at the end of 72 and 96 h. The initial increase followed by a decline of ChE activity was also observed during the experiment. These results suggest that cardiac glycosides seriously impair normal physiological metabolism, resulting in fatal alterations in major biochemical constituents of hepatopancreas tissues of P. canaliculata.

  11. Reproductive Ecology of the Giant African Snail in South Florida: Implications for Eradication Programs

    PubMed Central

    2016-01-01

    Giant African snail (Achatina fulica (Bowdich, 1822)), an important invasive snail, was recently found in South Florida, USA. An extensive eradication effort was initiated consisting of pesticide applications, debris removal and hand collections. We studied the reproduction capacity and population dynamics of snails collected from 22 populations for two years to help evaluate the likely success of the eradication program. A total of 23,890 snails, ranging from 25–131 mm, were measured, dissected and the number of eggs in each snail counted. Gravid snails ranged from 48–128 mm. Only 5% of snails had eggs, which were found year round. As the snails increased in size, they were more likely to include reproducing individuals. However, the percentage of gravid snails peaked when snails were approximately 90 mm. Although more prevalent, small (<65 mm) adults contributed fewer eggs to the population than the larger snails. We evaluated the effect of control measures on six populations having >1000 adult snails and used data from the two largest populations to investigate how environmental factors (temperature, humidity, and rainfall) interacted with population dynamics and control measures. More snails were collected in weeks with high humidity and more gravid snails were collected when the temperature was higher. The addition of metaldehyde pesticides had the greatest impact on population dynamics by reducing snail numbers. In populations with fewer snails, their numbers were already declining before the use of metaldehyde, although the new treatment accelerated the process. As a consequence of the eradication program, egg-producing snails were no longer collected from most populations by the end of the study. The aggressive and persistent control efforts apparently lead to reduced populations of egg producing snails, eventually resulting in local extinctions of this important pest. PMID:27861504

  12. Reproductive Ecology of the Giant African Snail in South Florida: Implications for Eradication Programs.

    PubMed

    Roda, Amy; Nachman, Gösta; Weihman, Scott; Yong Cong, Mary; Zimmerman, Fredrick

    2016-01-01

    Giant African snail (Achatina fulica (Bowdich, 1822)), an important invasive snail, was recently found in South Florida, USA. An extensive eradication effort was initiated consisting of pesticide applications, debris removal and hand collections. We studied the reproduction capacity and population dynamics of snails collected from 22 populations for two years to help evaluate the likely success of the eradication program. A total of 23,890 snails, ranging from 25-131 mm, were measured, dissected and the number of eggs in each snail counted. Gravid snails ranged from 48-128 mm. Only 5% of snails had eggs, which were found year round. As the snails increased in size, they were more likely to include reproducing individuals. However, the percentage of gravid snails peaked when snails were approximately 90 mm. Although more prevalent, small (<65 mm) adults contributed fewer eggs to the population than the larger snails. We evaluated the effect of control measures on six populations having >1000 adult snails and used data from the two largest populations to investigate how environmental factors (temperature, humidity, and rainfall) interacted with population dynamics and control measures. More snails were collected in weeks with high humidity and more gravid snails were collected when the temperature was higher. The addition of metaldehyde pesticides had the greatest impact on population dynamics by reducing snail numbers. In populations with fewer snails, their numbers were already declining before the use of metaldehyde, although the new treatment accelerated the process. As a consequence of the eradication program, egg-producing snails were no longer collected from most populations by the end of the study. The aggressive and persistent control efforts apparently lead to reduced populations of egg producing snails, eventually resulting in local extinctions of this important pest.

  13. 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.

  14. 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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-01-01

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

  17. Prostaglandin E₂ receptor EP2 mediates Snail expression in hepatocellular carcinoma cells.

    PubMed

    Cheng, Shan-Yu; Zhang, Hai; Zhang, Min; Xia, Shu-Kai; Bai, Xiao-Ming; Zhang, Li; Ma, Juan; Rong, Rong; Wang, Yi-Pin; Du, Ming-Zhan; Wang, Jie; Chen, Meng; Shi, Feng; Yang, Qin-Yi; Leng, Jing

    2014-05-01

    Prostaglandin E2 (PGE2) has been shown to influence cell invasion and metastasis in several types of cancer, including hepatocellular carcinoma (HCC). however, the molecular mechanisms underlying it remain to be further elucidated. Snail, as one of key inducers of epithelial-mesenchymal transition (EMT), plays pivotal roles in HCC invasion and metastasis. The present study was designed to evaluate the possible signaling pathways through which PGE2 regulates Snail protein expression in HCC cell lines. PGE2 markedly enhanced Huh-7 cell invasion and migration ability by upregulating the expression level of Snail protein, and EP2 receptor played an important role in this process. Src, EGFR, Akt and mTOR were all activated and involved in the regulation of snail protein expression. Our findings suggest that PGE2 could upregulate the expression level of Snail protein through the EP2/Src/EGFR/Akt/mTOR pathway in Huh-7 cells, which promotes HCC cell invasion and migration.

  18. Snail Shell Science.

    ERIC Educational Resources Information Center

    Matthews, Catherine

    1992-01-01

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

  19. The Classroom Animal: Snails.

    ERIC Educational Resources Information Center

    Kramer, David S.

    1985-01-01

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

  20. Tracing the Invasion of the Mediterranean Land Snail Cornu aspersum aspersum Becoming an Agricultural and Garden Pest in Areas Recently Introduced

    PubMed Central

    Guiller, Annie; Martin, Marie-Claire; Hiraux, Céline; Madec, Luc

    2012-01-01

    This study is the first on the genetics of invasive populations of one of the most widely spread land mollusc species known in the world, the “Brown Snail” Cornu aspersum aspersum. Deliberately or accidentally imported, the species has become recently a notorious pest outside its native Mediterranean range. We compared the spatial structure and genetic variability of invasive (America, Oceania, South Africa) versus native populations using five microsatellite loci and mitochondrial (Cyt b and 16S rRNA) genes as a first step towards (i) the detection of potential source populations, and (ii) a better understanding of mechanisms governing evolutionary changes involved in the invasion process. Results based on multivariate analysis (Discriminant Analysis of Principal Components), Bayesian statistical inference (Clustering, Approximate Bayesian Computation) and demographic tests allowed a construction of the introduction pathways of the species over recent centuries. While emigrants originated from only one of the two native lineages, the West one, the most likely scenario involved several introduction events and “source switching” comprising (i) an early stage (around 1660) of simultaneous introductions from Europe (France, Spain) towards Oceania (New Zealand) and California, (ii) from the early 18th century, a second colonization wave from bridgehead populations successfully established in California, (iii) genetic admixture in invasive areas where highly divergent populations came into contact as in New Zealand. Although these man-made pathways are consistent with historical data, introduction time estimates suggest that the two putative waves of invasion would have occurred long before the first field observations recorded, both in America and in Oceania. A prolonged lag period as the use of an incorrect generation time could explain such 100–150 years discrepancy. Lastly, the contrasting patterns of neutral genetic signal left in invasive populations are

  1. Snail levels control the migration mechanism of mesenchymal tumor cells

    PubMed Central

    BELGIOVINE, CRISTINA; CHIESA, GIULIO; CHIODI, ILARIA; FRAPOLLI, ROBERTA; BONEZZI, KATIUSCIA; TARABOLETTI, GIULIA; D'INCALCI, MAURIZIO; MONDELLO, CHIARA

    2016-01-01

    Cancer cells use two major types of movement: Mesenchymal, which is typical of cells of mesenchymal origin and depends on matrix metalloproteinase (MMP) activity, and amoeboid, which is characteristic of cells with a rounded shape and relies on the activity of Rho-associated kinase (ROCK). The present authors previously demonstrated that, during neoplastic transformation, telomerase-immortalized human fibroblasts (cen3tel cells) acquired a ROCK-dependent/MMP independent mechanism of invasion, mediated by the downregulation of the ROCK cellular inhibitor Round (Rnd)3/RhoE. In the present study, cen3tel transformation was also demonstrated to be paralleled by downregulation of Snail, a major determinant of the mesenchymal movement. To test whether Snail levels could determine the type of movement adopted by mesenchymal tumor cells, Snail was ectopically expressed in tumorigenic cells. It was observed that ectopic Snail did not increase the levels of typical mesenchymal markers, but induced cells to adopt an MMP-dependent mechanism of invasion. In cells expressing ectopic Snail, invasion became sensitive to the MMP inhibitor Ro 28–2653 and insensitive to the ROCK inhibitor Y27632, suggesting that, once induced by Snail, the mesenchymal movement prevails over the amoeboid one. Snail-expressing cells had a more aggressive behavior in vivo, and exhibited increased tumor growth rate and metastatic ability. These results confirm the high plasticity of cancer cells, which can adopt different types of movement in response to changes in the expression of specific genes. Furthermore, the present findings indicate that Rnd3 and Snail are possible regulators of the type of invasion mechanism adopted by mesenchymal tumor cells. PMID:27347214

  2. Snail levels control the migration mechanism of mesenchymal tumor cells.

    PubMed

    Belgiovine, Cristina; Chiesa, Giulio; Chiodi, Ilaria; Frapolli, Roberta; Bonezzi, Katiuscia; Taraboletti, Giulia; D'Incalci, Maurizio; Mondello, Chiara

    2016-07-01

    Cancer cells use two major types of movement: Mesenchymal, which is typical of cells of mesenchymal origin and depends on matrix metalloproteinase (MMP) activity, and amoeboid, which is characteristic of cells with a rounded shape and relies on the activity of Rho-associated kinase (ROCK). The present authors previously demonstrated that, during neoplastic transformation, telomerase-immortalized human fibroblasts (cen3tel cells) acquired a ROCK-dependent/MMP independent mechanism of invasion, mediated by the downregulation of the ROCK cellular inhibitor Round (Rnd)3/RhoE. In the present study, cen3tel transformation was also demonstrated to be paralleled by downregulation of Snail, a major determinant of the mesenchymal movement. To test whether Snail levels could determine the type of movement adopted by mesenchymal tumor cells, Snail was ectopically expressed in tumorigenic cells. It was observed that ectopic Snail did not increase the levels of typical mesenchymal markers, but induced cells to adopt an MMP-dependent mechanism of invasion. In cells expressing ectopic Snail, invasion became sensitive to the MMP inhibitor Ro 28-2653 and insensitive to the ROCK inhibitor Y27632, suggesting that, once induced by Snail, the mesenchymal movement prevails over the amoeboid one. Snail-expressing cells had a more aggressive behavior in vivo, and exhibited increased tumor growth rate and metastatic ability. These results confirm the high plasticity of cancer cells, which can adopt different types of movement in response to changes in the expression of specific genes. Furthermore, the present findings indicate that Rnd3 and Snail are possible regulators of the type of invasion mechanism adopted by mesenchymal tumor cells.

  3. Widespread and persistent invasions of terrestrial habitats coincident with larval feeding behavior transitions during snail-killing fly evolution (Diptera: Sciomyzidae)

    PubMed Central

    2012-01-01

    Background Transitions in habitats and feeding behaviors were fundamental to the diversification of life on Earth. There is ongoing debate regarding the typical directionality of transitions between aquatic and terrestrial habitats and the mechanisms responsible for the preponderance of terrestrial to aquatic transitions. Snail-killing flies (Diptera: Sciomyzidae) represent an excellent model system to study such transitions because their larvae display a range of feeding behaviors, being predators, parasitoids or saprophages of a variety of mollusks in freshwater, shoreline and dry terrestrial habitats. The remarkable genus Tetanocera (Tetanocerini) occupies five larval feeding groups and all of the habitat types mentioned above. This study has four principal objectives: (i) construct a robust estimate of phylogeny for Tetanocera and Tetanocerini, (ii) estimate the evolutionary transitions in larval feeding behaviors and habitats, (iii) test the monophyly of feeding groups and (iv) identify mechanisms underlying sciomyzid habitat and feeding behavior evolution. Results Bayesian inference and maximum likelihood analyses of molecular data provided strong support that the Sciomyzini, Tetanocerini and Tetanocera are monophyletic. However, the monophyly of many behavioral groupings was rejected via phylogenetic constraint analyses. We determined that (i) the ancestral sciomyzid lineage was terrestrial, (ii) there was a single terrestrial to aquatic habitat transition early in the evolution of the Tetanocerini and (iii) there were at least 10 independent aquatic to terrestrial habitat transitions and at least 15 feeding behavior transitions during tetanocerine phylogenesis. The ancestor of Tetanocera was aquatic with five lineages making independent transitions to terrestrial habitats and seven making independent transitions in feeding behaviors. Conclusions The preponderance of aquatic to terrestrial transitions in sciomyzids goes against the trend generally observed

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

    PubMed

    Zhang, Jianping; Zhou, Yunzhe; Yang, Yonggang

    2015-02-01

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

  5. Lumican Inhibits SNAIL-Induced Melanoma Cell Migration Specifically by Blocking MMP-14 Activity

    PubMed Central

    Stasiak, Marta; Boncela, Joanna; Perreau, Corinne; Karamanou, Konstantina; Chatron-Colliet, Aurore; Proult, Isabelle; Przygodzka, Patrycja; Chakravarti, Shukti; Maquart, François-Xavier; Kowalska, M. Anna; Wegrowski, Yanusz; Brézillon, Stéphane

    2016-01-01

    Lumican, a small leucine rich proteoglycan, inhibits MMP-14 activity and melanoma cell migration in vitro and in vivo. Snail triggers epithelial-mesenchymal transitions endowing epithelial cells with migratory and invasive properties during tumor progression. The aim of this work was to investigate lumican effects on MMP-14 activity and migration of Snail overexpressing B16F1 (Snail-B16F1) melanoma cells and HT-29 colon adenocarcinoma cells. Lumican inhibits the Snail induced MMP-14 activity in B16F1 but not in HT-29 cells. In Snail-B16F1 cells, lumican inhibits migration, growth, and melanoma primary tumor development. A lumican-based strategy targeting Snail-induced MMP-14 activity might be useful for melanoma treatment. PMID:26930497

  6. Lichen endozoochory by snails.

    PubMed

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

    2011-04-13

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

  7. 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.

  8. Snail controls the mesenchymal phenotype and drives erlotinib resistance in Oral epithelial and HNSCC cells

    PubMed Central

    Dennis, Miranda; Wang, Guanyu; Luo, Jie; Lin, Yuan; Dohadwala, Mariam; Sidell, Douglas; DeConde, Adam; Abemayor, Elliot; Elashoff, David A.; Sharma, Sherven; Dubinett, Steven M.; St John, Maie A.

    2014-01-01

    PURPOSE The presence of regional metastases in HNSCC patients is a common and adverse event associated with poor prognosis. Understanding the molecular mechanisms that mediate HNSCC metastasis may enable identification of novel therapeutic targets. Our recent work on human HNSCC tissues underlies Snail’s role as a molecular prognostic marker for HNSCC. Snail positivity is significantly predictive of poorly differentiated, lymphovascular invasive, as well as regionally metastatic tumors. We recently reported the role of Snail in the inflammation-induced promotion of EMT in HNSCC. However, other important Snail-dependent malignant phenotypes have not been fully explored. Here, we investigate the capacity of Snail to drive EMT in human oral epithelial cell lines, and its ability to confer drug resistance. EXPERIMENTAL DESIGN Snail was overexpressed HNSCC and oral epithelial cell lines. AIG assays, wound healing assays, invasion & migration assays, spheroid modeling, and cell survival assays were performed. RESULTS The overexpression of Snail in human HNSCC and oral epithelial cell lines drives EMT. The sole transfection of Snail confers the expression of a mesenchymal molecular signature including down-regulation of the epithelial adherens, such as E-cadherin and β-catenin, and induction of mesenchymal markers, Snail overexpressing cell lines demonstrate rapid growth in Anchorage-independent growth assays; a decreased capacity to form tight spheroids; increased resistance to erlotinib; and have an increased capacity for invasion. CONCLUSION Snail controls the mesenchymal phenotype and drives erlotinib resistance in HNSCC cells. Snail may prove to be a useful marker in predicting EGFR inhibitor responsiveness. PMID:22568942

  9. 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)

  10. 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 TGFβ 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.

  11. 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.

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

    PubMed

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

    2009-09-21

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

  13. 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

  14. Snail Promotes Epithelial Mesenchymal Transition in Breast Cancer Cells in Part via Activation of Nuclear ERK2

    PubMed Central

    Smith, Bethany N.; Burton, Liza J.; Henderson, Veronica; Randle, Diandra D.; Morton, Derrick J.; Smith, Basil A.; Taliaferro-Smith, Latonia; Nagappan, Peri; Yates, Clayton; Zayzafoon, Majd; Chung, Leland W. K.; Odero-Marah, Valerie A.

    2014-01-01

    Snail transcription factor is up-regulated in several cancers and associated with increased tumor migration and invasion via induction of epithelial-to-mesenchymal transition (EMT). MAPK (ERK1/2) signaling regulates cellular processes including cell motility, adhesion, and invasion. We investigated the regulation of ERK1/2 by Snail in breast cancer cells. ERK1/2 activity (p-ERK) was higher in breast cancer patient tissue as compared to normal tissue. Snail and p-ERK were increased in several breast cancer cell lines as compared to normal mammary epithelial cells. Snail knockdown in MDA-MB-231 and T47-D breast cancer cells decreased or re-localized p-ERK from the nuclear compartment to the cytoplasm. Snail overexpression in MCF-7 breast cancer cells induced EMT, increased cell migration, decreased cell adhesion and also increased tumorigenicity. Snail induced nuclear translocation of p-ERK, and the activation of its subcellular downstream effector, Elk-1. Inhibiting MAPK activity with UO126 or knockdown of ERK2 isoform with siRNA in MCF-7 Snail cells reverted EMT induced by Snail as shown by decreased Snail and vimentin expression, decreased cell migration and increased cell adhesion. Overall, our data suggest that ERK2 isoform activation by Snail in aggressive breast cancer cells leads to EMT associated with increased cell migration and decreased cell adhesion. This regulation is enhanced by positive feedback regulation of Snail by ERK2. Therefore, therapeutic targeting of ERK2 isoform may be beneficial for breast cancer. PMID:25122124

  15. Snail-Induced Epithelial-to-Mesenchymal Transition Enhances P-gp-Mediated Multi Drug Resistance in HCC827 Cells.

    PubMed

    Tomono, Takumi; Yano, Kentaro; Ogihara, Takuo

    2017-03-17

    Overexpression and/or activation of P-glycoprotein (P-gp), which mediates efflux transport of various anti-cancer drugs in cancer cells, are associated with multi-drug resistance (MDR). On the other hand, malignant cancer cells frequently undergo epithelial-to-mesenchymal transition (EMT), thereby acquiring high migratory mobility and invasive ability. Snail is a transcriptional factor that represses multiple other factors, and its overexpression is a trigger of EMT. Since both P-gp and Snail are involved in malignant evolution of cancer, in this work, we evaluated whether or not EMT induced by overexpression of Snail influences P-gp expression and/or activity. Snail-overexpressing cells showed downregulation of epithelial markers, E-cadherin, occludin and claudin-1, and upregulation of mesenchymal markers, vimenin and ZEB1. Although Western blot analysis showed that P-gp expression levels were similar in Mock and Snail-overexpressing cells, the results of P-gp functional assays with P-gp substrates rhodamine123 and paclitaxel indicated that P-gp is activated in Snail-overexpressing cells. Indeed, Snail-overexpressing cells showed greater viability than Mock cells in the presence of paclitaxel. We observed caveolin-1 dephosphorylation and decreased GRB2 expression in Snail-overexpressing cells. These findings suggest a novel pathway leading to cancer MDR, in which Snail induces EMT concomitantly with a decrease of GRB2-mediated caveolin-1 phosphorylation, resulting in activation of P-gp.

  16. Snail up-regulates pro-inflammatory mediators and inhibits differentiation in oral keratinocytes

    PubMed Central

    Lyons, J. Guy; Patel, Vyomesh; Roue, Naomi C.; Fok, Sandra Y.; Soon, Lilian L.; Halliday, Gary M.; Gutkind, J. Silvio

    2008-01-01

    The transcriptional repressor, Snail2, is over-expressed in head and neck squamous cell carcinomas (HNSCCs) relative to non-malignant head and neck mucosal epithelium, and in locally recurrent relative to non-recurrent HNSCCs. We investigated the mechanisms by which Snails might contribute to the pathogenesis of HNSCCs using cell biological and molecular analyses. Oral keratinocytes that expressed Snails acquired an enhanced ability to attract monocytes and to invade a dense interstitial collagen matrix. They were also found to up-regulate production of pro-inflammatory cytokines and cyclooxygenase-2 (COX2), which have previously been shown to correlate with malignancy. Induction of nuclear factor-kappa B transcriptional activity by Snails was weak and not sufficient to account for the elevated levels of COX2, interleukin-6, interleukin-8 or CXCL1. In addition, expression of Snails in oral keratinocytes impaired desquamation in vitro and strongly repressed expression of both ELF3 and matriptase-1, which play important roles in the terminal differentiation of keratinocytes. Re-expression of matriptase-1 in Snail-expressing cells partially rescued desquamation. This implicates Snails as contributing to malignancy both at the early stages, by impeding terminal differentiation, and at later stages, when invasion and inflammation are important. PMID:18559496

  17. Pomacea canaliculata (Mollusca, Gastropoda) in Patagonia: potential role of climatic change in its dispersion and settlement.

    PubMed

    Darrigran, G; Damborenea, C; Tambussi, A

    2011-02-01

    Pomacea canaliculata (Lamarck, 1822) (Mollusca Gastropoda) shows a large native distribution range in South America, reaching as far south as 37º S (Buenos Aires, Argentina). This species was deliberately introduced into Southeast Asia around 1980 and subsequently underwent a rapid intentional or accidental dispersal into many countries in the region. It was also introduced into North and Central America and Hawaii. In this contribution we record the presence of P. canaliculata in Patagonia, assessing the possible influence of climatic change in the new establishment of this species there. Three samplings (between September 2004 and April 2005) were carried out at 38º 58' 20.2" S-68º 11' 27.3" W. In the sampling we found two adult specimens of P. canaliculata and numerous egg clutches. Pomacea canaliculata is naturally distributed in the Plata and Amazon Basins. The southern boundary of this species has been established as the isotherms of 14 ºC and 16 ºC in Buenos Aires province, and precipitations of 900 to 600 mm/year. This study also analysed variations in annual temperature and precipitation in Patagonia. Average temperatures show an increase over the years, although not constantly. Important modifications in precipitation regime in northern Patagonia, triggered by global climatic changes, could be beneficial for the settlement of populations of P. canaliculata in this new area, where precipitation increased enough to reach values similar to those in the southernmost area of distribution of this species.

  18. 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.

  19. ALTERNATE FOOD-CHAIN TRANSFER OF THE TOXIN LINKED TO AVIAN VACUOLAR MYELINOPATHY AND IMPLICATIONS FOR THE ENDANGERED FLORIDA SNAIL KITE (ROSTRHAMUS SOCIABILIS).

    PubMed

    Dodd, Shelley R; Haynie, Rebecca S; Williams, Susan M; Wilde, Susan B

    2016-04-28

    Avian vacuolar myelinopathy (AVM) is a neurologic disease causing recurrent mortality of Bald Eagles ( Haliaeetus leucocephalus ) and American Coots ( Fulica americana ) at reservoirs and small impoundments in the southern US. Since 1994, AVM is considered the cause of death for over 170 Bald Eagles and thousands of American Coots and other species of wild birds. Previous studies link the disease to an uncharacterized toxin produced by a recently described cyanobacterium, Aetokthonos hydrillicola gen. et sp. nov. that grows epiphytically on submerged aquatic vegetation (SAV). The toxin accumulates, likely in the gastrointestinal tract of waterbirds that consume SAV, and birds of prey are exposed when feeding on the moribund waterbirds. Aetokthonos hydrillicola has been identified in all reservoirs where AVM deaths have occurred and was identified growing abundantly on an exotic SAV hydrilla ( Hydrilla verticillata ) in Lake Tohopekaliga (Toho) in central Florida. Toho supports a breeding population of a federally endangered raptor, the Florida Snail Kite ( Rostrhamus sociabilis ) and a dense infestation of an exotic herbivorous aquatic snail, the island applesnail ( Pomacea maculata ), a primary source of food for resident Snail Kites. We investigated the potential for transmission in a new food chain and, in laboratory feeding trials, confirmed that the AVM toxin was present in the hydrilla/A. hydrillicola matrix collected from Toho. Additionally, laboratory birds that were fed apple snails feeding on hydrilla/A. hydrillicola material from a confirmed AVM site displayed clinical signs (3/5), and all five developed brain lesions unique to AVM. This documentation of AVM toxin in central Florida and the demonstration of AVM toxin transfer through invertebrates indicate a significant risk to the already diminished population of endangered Snail Kites.

  20. Small Molecules in the Cone Snail Arsenal.

    PubMed

    Neves, Jorge L B; Lin, Zhenjian; Imperial, Julita S; Antunes, Agostinho; Vasconcelos, Vitor; Olivera, Baldomero M; Schmidt, Eric W

    2015-10-16

    Cone snails are renowned for producing peptide-based venom, containing conopeptides and conotoxins, to capture their prey. A novel small-molecule guanine derivative with unprecedented features, genuanine, was isolated from the venom of two cone snail species. Genuanine causes paralysis in mice, indicating that small molecules and not just polypeptides may contribute to the activity of cone snail venom.

  1. Extremely high secondary production of introduced snails in rivers.

    PubMed

    Hall, Robert O; Dybdahl, Mark F; VanderLoop, Maria C

    2006-06-01

    The functional importance of invasive animals may be measured as the degree to which they dominate secondary production, relative to native animals. We used this approach to examine dominance of invertebrate secondary production by invasive New Zealand mudsnails (Potamopyrgus antipodarum) in rivers. We measured secondary production of mudsnails and native invertebrates in three rivers in the Greater Yellowstone Area (Wyoming, USA): Gibbon River, Firehole River, and Polecat Creek. Potamopyrgus production was estimated by measuring in situ growth rates and multiplying by monthly biomass; native invertebrate production was estimated using size frequency and instantaneous growth methods. Mudsnail growth rates were high (up to 0.06 d(-1)) for juvenile snails and much lower for adult females (0.003 d(-1)). Potamopyrgus production in Polecat Creek (194 g x m(-2) x yr(-1)) was one of the highest values ever reported for a stream invertebrate. Native invertebrate production ranged from 4.4 to 51 g x m(-2) x yr(-1). Potamopyrgus was the most productive taxon and constituted 65-92% of total invertebrate productivity. Native invertebrate production was low in all streams. Based on a survey of production measures from uninvaded rivers, the distribution of secondary production across taxa was much more highly skewed toward the invasive dominant Potamopyrgus in the three rivers. We suggest that this invasive herbivorous snail is sequestering a large fraction of the carbon available for invertebrate production and altering food web function.

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

    PubMed Central

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

    2012-01-01

    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 γ-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 γ-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

  3. Toxicity of copper sulfate and rotenone to Chinese mystery snail (Bellamya chinensis)

    USGS Publications Warehouse

    Haak, Danielle M.; Stephen, Bruce J.; Kill, Robert A.; Smeenk, Nicholas A.; Allen, Craig R.; Pope, Kevin L.

    2014-01-01

    The Chinese mystery snail (Bellamya chinensis) is a freshwater snail native to Southeast Asia, Japan, and Russia and is currently classified as an invasive species in at least 27 states in the USA. The species tolerates a wide range of environmental conditions, making management of established populations difficult. We tested the efficacy of two traditional chemical treatments, rotenone and copper sulfate, on the elimination of adult Chinese mystery snails in laboratory experiments. All snails (N=50) survived 72-hour exposure to rotenone-treated lake water, and 96% (N=25) survived 72-hour exposure to pre-determined rotenone concentrations of 0.25, 2.5, and 25.0 mg/L. All snails (N=10) survived exposure to 1.25 mg/L copper sulfate solution, 90% (N=10) survived exposure to 2.50 mg/L copper sulfate solution, and 80% (N=5) survived exposure to 5.0 mg/L copper sulfate solution. Neither rotenone nor copper sulfate effectively killed adult Chinese mystery snails in laboratory experiments, most likely due to their relatively large size, thick shell, and operculum. Therefore, it appears that populations will be very difficult to control once established, and management should focus on preventing additional spread or introductions of this species.

  4. Morphological Variation in the New Zealand Mud Snail (Potamopyrgus antipodarum).

    NASA Astrophysics Data System (ADS)

    Barrow, S.; Holomuzki, J. R.; Brunkow, P. E.

    2005-05-01

    The New Zealand mud snail (Potamopyrgus antipodarum) is a morphologically diverse species, showing variation in body shape and spine ornamentation. Native to New Zealand, the snail is highly invasive in the United States and Europe. As part of a broader study examining the role of morphological variation in hydrodynamic performance, we sought to quantify shell variation in snails from four different populations in New Zealand. Shells were mounted and photographed, and four characters (shell length and width, and aperture length and width) were digitized. Shell length differed significantly among populations. Sheared PCA revealed that shell shape, defined in terms of overall robustness (PC1) as well as the ratio between shell width and aperture width (PC2), also differed significantly among populations. Spined shells differed significantly from smooth shells with respect to shell shape (PC1 and PC2), with spined shells being generally more robust with larger apertures for their length. Shell shape differed significantly between spined and smooth shells in the two lotic habitats but not in the lentic habitats, suggesting a possible interaction between shell shape, presence of spines, and hydrodynamic environment. Further research will attempt to relate shell morphology and spine ornamentation to hydrodynamic drag and lift forces.

  5. Reversibility of the Snail-induced epithelial-mesenchymal transition revealed by the Cre-loxP system.

    PubMed

    Ozawa, Masayuki; Kobayashi, Wakako

    2015-03-13

    The epithelial-mesenchymal transition (EMT), a key process in the tumor metastatic cascade, is characterized by the loss of cell-cell junctions and cell polarity, as well as the acquisition of migratory and invasive properties. Snail is an EMT-inducer whose expression in several different epithelial cells, e.g., Madin-Darby canine kidney (MDCK), leads to EMT. To further understand EMT induced by Snail expression, the Cre-loxP site-specific recombination system was used to investigate its reversibility. Transfection of MDCK cells with loxP-flanked Snail (Snail-loxP) resulted in EMT induction, which included the acquisition of a spindle-shaped fibroblastic morphology, the downregulation of epithelial markers, and the upregulation of mesenchymal markers. DNA methylation of the E-cadherin promoter, which often occurs during E-cadherin downregulation, was not observed in Snail+ cells. After Cre-mediated excision of Snail-loxP, the cells reacquired an epithelial morphology, upregulated epithelial markers, and downregulated mesenchymal markers. Thus, EMT induced by Snail expression was reversible.

  6. A SNAIL1-SMAD3/4 transcriptional repressor complex promotes TGF-β mediated epithelial-mesenchymal transition

    PubMed Central

    Vincent, Theresa; Neve, Etienne P. A.; Johnson, Jill R.; Kukalev, Alexander; Rojo, Federico; Albanell, Joan; Pietras, Kristian; Virtanen, Ismo; Philipson, Lennart; Leopold, Philip L.; Crystal, Ronald G.; de Herreros, Antonio Garcia; Moustakas, Aristidis; Pettersson, Ralf F.; Fuxe, Jonas

    2013-01-01

    Epithelial-mesenchymal transitions (EMT) are essential for organogenesis and triggered in carcinoma progression into an invasive state1. Transforming growth factor-β (TGF-β) cooperates with signalling pathways, such as Ras and Wnt, to induce EMT2-5, but the molecular mechanisms are not clear. Here, we report that SMAD3 and SMAD4 interact and form a complex with SNAIL1, a transcriptional repressor and promoter of EMT6, 7. The SNAIL1-SMAD3/4 complex was targeted to the gene promoters of CAR, a tight junction protein, and E-cadherin during TGF-β-driven EMT in breast epithelial cells. SNAIL1 and SMAD3/4 acted as co-repressors of CAR, occludin, claudin-3 and E-cadherin promoters in transfected cells. Conversely, co-silencing of SNAIL1 and SMAD4 by siRNA inhibited the repression of CAR and occludin during EMT. Moreover, loss of CAR and E-cadherin correlated with nuclear co-expression of SNAIL1 and SMAD3/4 in a mouse model of breast carcinoma and at the invasive fronts of human breast cancer. We propose that activation of a SNAIL1-SMAD3/4 transcriptional complex represents a novel mechanism of gene repression during EMT. PMID:19597490

  7. 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

  8. 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.

  9. CELSS nutrition system utilizing snails.

    PubMed

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

    1993-08-01

    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 m3 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 B2, 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 above mentioned lacking elements. We evaluate the snail breeder and the associated food supply system as a subsystem of closed ecological life support system.

  10. Polyethyleneimine (PEI) Mediated siRNA Gene Silencing in the Schistosoma mansoni Snail Host, Biomphalaria glabrata

    PubMed Central

    Knight, Matty; Miller, Andre; Liu, Yijia; Scaria, Puthupparampil; Woodle, Martin; Ittiprasert, Wannaporn

    2011-01-01

    An in vivo, non-invasive technique for gene silencing by RNA interference (RNAi) in the snail, Biomphalaria glabrata, has been developed using cationic polymer polyethyleneimine (PEI) mediated delivery of long double-stranded (ds) and small interfering (si) RNA. Cellular delivery was evaluated and optimized by using a ‘mock’ fluorescent siRNA. Subsequently, we used the method to suppress expression of Cathepsin B (CathB) with either the corresponding siRNA or dsRNA of this transcript. In addition, the knockdown of peroxiredoxin (Prx) at both RNA and protein levels was achieved with the PEI-mediated soaking method. B. glabrata is an important snail host for the transmission of the parasitic digenean platyhelminth, Schistosoma mansoni that causes schistosomiasis in the neotropics. Progress is being made to realize the genome sequence of the snail and to uncover gene expression profiles and cellular pathways that enable the snail to either prevent or sustain an infection. Using PEI complexes, a convenient soaking method has been developed, enabling functional gene knockdown studies with either dsRNA or siRNA. The protocol developed offers a first whole organism method for host-parasite gene function studies needed to identify key mechanisms required for parasite development in the snail host, which ultimately are needed as points for disrupting this parasite mediated disease. PMID:21765961

  11. Characterisation of Reproduction-Associated Genes and Peptides in the Pest Land Snail, Theba pisana

    PubMed Central

    Stewart, Michael J.; Wang, Tianfang; Harding, Bradley I.; Bose, U.; Wyeth, Russell C.; Storey, Kenneth B.; Cummins, Scott F.

    2016-01-01

    Increased understanding of the molecular components involved in reproduction may assist in understanding the evolutionary adaptations used by animals, including hermaphrodites, to produce offspring and retain a continuation of their lineage. In this study, we focus on the Mediterranean snail, Theba pisana, a hermaphroditic land snail that has become a highly invasive pest species within agricultural areas throughout the world. Our analysis of T. pisana CNS tissue has revealed gene transcripts encoding molluscan reproduction-associated proteins including APGWamide, gonadotropin-releasing hormone (GnRH) and an egg-laying hormone (ELH). ELH isoform 1 (ELH1) is known to be a potent reproductive peptide hormone involved in ovulation and egg-laying in some aquatic molluscs. Two other non-CNS ELH isoforms were also present in T. pisana (Tpi-ELH2 and Tpi-ELH3) within the snail dart sac and mucous glands. Bioactivity of a synthetic ELH1 on sexually mature T. pisana was confirmed through bioassay, with snails showing ELH1-induced egg-laying behaviours, including soil burrowing and oviposition. In summary, this study presents a detailed molecular analysis of reproductive neuropeptide genes in a land snail and provides a foundation for understanding ELH function. PMID:27706146

  12. Toxicity of Barringtonia racemosa (L.) Kernel Extract on Pomacea canaliculata (Ampullariidae)

    PubMed Central

    Musman, Musri

    2010-01-01

    A number of tropical plant species have been recognised as molluscicidal plants, and Barringtonia racemosa (L.) is one of these. The toxicity effects of B. racemosa seed kernel extracts on Pomacea canaliculata were evaluated. The lethal concentration at 50% [LC50 (lower-upper limits)] values, in ppm/48 hours, were 70.71 (41.33–120.97), 94.39 (62.48–142.59), 186.84 (129.21–270.17), and 672.72 (366.57–1234.53) for the extracts withdrawn using dichloromethane (DCM), methanol (MeOH), ethyl acetate (EtOAc), heptane (hp) solvents, respectively at 95% confidence interval (C. I.). All analyses were conducted using Trimmed Spearman-Karber (TSK) program version 1.5. It is assumed that the observed biological effects of the extracts may be due to the saponins and flavonoids present in the seed. The dichloromethanic and methanolic extracts contain saponin and flavonoid substances. Therefore these extracts have shown more potent molluscicidal activity towards the tested organism compared to the remaining extracts. This observed biological activity suggests a promising role for B. racemosa in the control of P. canaliculata. PMID:24575198

  13. 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…

  14. Valproic acid (VPA) promotes the epithelial mesenchymal transition of hepatocarcinoma cells via transcriptional and post-transcriptional up regulation of Snail.

    PubMed

    Wu, Lei; Feng, Hua; Hu, Jinhua; Tian, Xiangguo; Zhang, Chunqing

    2016-12-01

    Due to the low cost and favorable safety profile, valproic acid (VPA) has been considered as a potential candidate drug for therapy of various cancers. Our present study revealed that VPA, at the concentration (1mM) which has no effect on cell proliferation, can significantly increase the in vitro migration and invasion of hepatocarcinoma (HCC) HepG2 and Huh7 cells via induction of epithelial mesenchymal transition (EMT). VPA treatment can significantly increase the mRNA and protein expression of Snail, the key transcription factor of EMT. While knockdown of Snail can abolish VPA induced EMT of HCC cells. It suggested that Snail is essential for VPA induced EMT of HCC cells. VPA treatment also increased the phosphorylation of NF-κB p65. BAY 11-7082, the inhibitor of NF-κB, can significantly abolish VPA induced up regulation of Snail mRNA. Furthermore, VPA can increase the protein expression of Snail since 1h treatment via up regulation of half-lives of Snail protein. The increased protein stabilization of Snail can be attributed to VPA induced phosphorylation of Akt and GSK-3β. Collectively, our present study revealed that VPA can promote the EMT of HCC cells via up regulation of Snail through activation of NF-κB and Akt/GSK-3β signals.

  15. 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.

  16. Bioaccumulation of heavy metals in water, sediments, aquatic plant and histopathological effects on the golden apple snail in Beung Boraphet reservoir, Thailand.

    PubMed

    Dummee, Vipawee; Kruatrachue, Maleeya; Trinachartvanit, Wachareeporn; Tanhan, Phanwimol; Pokethitiyook, Prayad; Damrongphol, Praneet

    2012-12-01

    Changes in the seasonal concentrations of heavy metals (Cu, Mn, Fe, Zn, Pb and Cd) were determined in water, sediments, snails (Pomacea canaliculata) and aquatic plants (Ipomoea aquatica) in three selected tributaries of the Beung Boraphet reservoir, Nakhon Sawan Province, central Thailand. Only Fe, Cu, Mn and Zn were detected by FAAS in all samples collected. The water quality of Beung Boraphet was medium clean with Fe, Mn, Cu and Zn concentrations well below internationally accepted limits. According to the criteria proposed for sediments by the EPA Region V, Zn and Mn concentrations were within the non-polluted range while Fe and Cu (wet season) concentrations fell into the class of severely polluted sediment. Both P. canaliculata and I. aquatica bioconcentrated more Mn in their tissues than were found in sediments, especially in the wet season. The results of Pearson correlation study and BCF values also indicated similar findings. Only Mn showed the importance of sediment-to-snail concentration and high BCF values in both snails and plants. P. canaliculata exposed to contaminated sediment for two months, showed higher accumulation of metals (Fe, Mn, Cu and Zn) in the digestive tracts and digestive glands than in the foot muscles. Histopathological changes included alterations in the epithelial lining of the digestive tracts, digestive glands and the gills. Loss of cilia and increase in mucous cells were observed in the digestive tracts and gills, while the digestive glands exhibited an increase of dark granules and basophilic cells, and dilation of digestive cells. The results indicated that both P. canaliculata and I. aquatica could be used as biomonitors of sedimentary metal contamination for the Beung Boraphet reservoir.

  17. Mathematical simulation of an aquatic snail population*

    PubMed Central

    Jobin, W. R.; Michelson, E. H.

    1967-01-01

    Techniques for controlling the intermediate snail hosts of schistosomiasis have had to be evaluated by field trials, since the complexity of snail population dynamics has so far made it impossible to predict the effects of these techniques and thereby avoid costly field testing. However, in laboratory studies with Biomphalaria glabrata it was found that the fecundity of these snails was directly proportional to F/NV, where F is the total amount of food in the habitat, N the number of snails, and V the volume of the habitat. The use of this fecundity variable together with data published on snail longevity and fecundity made it possible to construct a mathematical model of a snail population which may eventually be useful for evaluating snail control methods. For preliminary verification of the model, its predictions were compared with a published history of a population of Bulinus globosus in a small pond. The general agreement of the predicted and observed population data indicated that the basic structure of the model was sound. PMID:5301741

  18. The snail Potamopyrgus antipodarum grows faster and is more active in the shade, independent of food quality.

    PubMed

    Liess, A; Lange, K

    2011-09-01

    Ecological stoichiometry has advanced food web ecology by emphasising the importance of food quality over food quantity for herbivores. Here, we focus on the effects of abiotic factors such as nutrients and light (known to influence food quality) on grazer growth rates. As model organism we used the mudsnail Potamopyrgus antipodarum that is native to New Zealand but invasive elsewhere. In a stream channel experiment in New Zealand, we manipulated light (two levels) and nutrients (four levels) to achieve a range of primary producer carbon: nutrient ratios and added mudsnails (3 densities + ungrazed control) to 128 periphyton covered stream channels in a 2 × 4 × 4 full factorial design. We measured snail growth rate and activity, food quality and nutritional imbalance, to test the predictions that (1) less light and more nutrients increase periphyton food quality and thus snail growth rates, and (2) less crowding leads to higher food availability and thus higher snail growth rates. We found that snail growth rates were higher under low light than under high light intensities and this difference increased with increasing nutrient addition. These changes in growth rate were not mediated by food quality in terms of periphyton nutrient ratios. Furthermore, experimental treatments strongly affected snail behaviour. Snails grazed more actively in the low light treatments, and thus it is more likely that snail growth rates were directly affected by light levels, maybe as a result of innate predator avoidance behaviour or as a reaction to high UV intensities. We conclude that in our stream channels snail growth rate was limited by factors other than food quality and quantity such as UV exposure, algal defences or the relatively low ambient water temperature.

  19. The transcription factors Slug and Snail act as repressors of Claudin-1 expression in epithelial cells1

    PubMed Central

    Martínez-Estrada, Ofelia M.; Cullerés, Albert; Soriano, Francesc X.; Peinado, Hector; Bolós, Victoria; Martínez, Fernando O.; Reina, Manuel; Cano, Amparo; Fabre, Myriam; Vilaró, Senén

    2005-01-01

    Claudin-1 is an integral membrane protein component of tight junctions. The Snail family of transcription factors are repressors that play a central role in the epithelial–mesenchymal transition, a process that occurs during cancer progression. Snail and Slug members are direct repressors of E-cadherin and act by binding to the specific E-boxes of its proximal promoter. In the present study, we demonstrate that overexpression of Slug or Snail causes a decrease in transepithelial electrical resistance. Overexpression of Slug and Snail in MDCK (Madin–Darby canine kidney) cells down-regulated Claudin-1 at protein and mRNA levels. In addition, Snail and Slug are able to effectively repress human Claudin-1-driven reporter gene constructs containing the wild-type promoter sequence, but not those with mutations in two proximal E-box elements. We also demonstrate by band-shift assay that Snail and Slug bind to the E-box motifs present in the human Claudin-1 promoter. Moreover, an inverse correlation in the levels of Claudin-1 and Slug transcripts were observed in breast cancer cell lines. E-box elements in the Claudin-1 promoter were found to play a critical negative regulatory role in breast cancer cell lines that expressed low levels of Claudin-1 transcript. Significantly, in invasive human breast tumours, high levels of Snail and Slug correlated with low levels of Claudin-1 expression. Taken together, these results support the hypothesis that Claudin-1 is a direct downstream target gene of Snail family factors in epithelial cells. PMID:16232121

  20. Cisplatin promotes mesenchymal-like characteristics in osteosarcoma through Snail

    PubMed Central

    Fang, Shuo; Yu, Ling; Mei, Hongjun; Yang, Jian; Gao, Tian; Cheng, Anyuan; Guo, Weichun; Xia, Kezhou; Liu, Gaiwei

    2016-01-01

    More than 30% of patients with osteosarcoma succumb to pulmonary metastases. Epithelial-mesenchymal transition (EMT) is a biological process by which tumor cells gain an increased capacity for invasiveness and metastasis. A previous study confirmed the phenomenon of EMT in osteosarcoma, a mesenchymal-derived tumor. However, whether chemotherapy affects EMT remains to be elucidated. In the present study, the osteosarcoma cells were exposed to a sublethal dose of cisplatin, and any surviving cells were assumed to be more resistant to cisplatin. In addition, these cells exhibited a more mesenchymal phenotype. Immunofluorescence analysis revealed that the cisplatin treated cells had an increased long/short axis ratio and increased expression of N-cadherin compared with control cells. A panel of EMT-associated genes was subsequently assessed by quantitative PCR and western blot analysis, and they were observed to be significantly upregulated in the cisplatin treated cells. The in vitro wound healing and Transwell assay indicated that the cisplatin treated cells were more prone to migrate and invade. An in vivo assay showed that the cisplatin-treated xenograft had increased expression of EMT-associated genes, and exhibited increased pulmonary lesions compared with the control, which indicated an elevated capacity to metastasize. The expression of Snail was knocked down by specific small interfering RNA, and it was observed that Snail inhibition promoted cisplatin sensitivity, and cisplatin-induced EMT was significantly blocked. Taken together, the results of the present study supported that idea that Snail participates in cisplatin-induced EMT in osteosarcoma cells, and targeting EMT-transcription factors may offer promise for the therapeutics of osteosarcoma. PMID:28105207

  1. 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

  2. Ichthyotoxicity caused by marine cone snail venoms?

    PubMed

    Mebs, Dietrich; Kauferstein, Silke

    2005-09-01

    Ten venoms from marine cone snails were tested for ichthyotoxic effects on zebra fish (Brachydanio rerio) when added to the water. Only two venoms, from Conus capitaneus and Conus episcopatus, produced lethal effects at high concentrations (50-300 microg/ml) within 20-90 min. No sedative or hypnotic symptoms were observed. The experiments confirm that Conus venoms exert a quick and prompt activity only by parenteral injection into the prey as it is performed by the snail.

  3. 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

  4. Regulation of heterochromatin transcription by Snail1/LOXL2 during epithelial-to-mesenchymal transition.

    PubMed

    Millanes-Romero, Alba; Herranz, Nicolás; Perrera, Valentina; Iturbide, Ane; Loubat-Casanovas, Jordina; Gil, Jesús; Jenuwein, Thomas; García de Herreros, Antonio; Peiró, Sandra

    2013-12-12

    Although heterochromatin is enriched with repressive traits, it is also actively transcribed, giving rise to large amounts of noncoding RNAs. Although these RNAs are responsible for the formation and maintenance of heterochromatin, little is known about how their transcription is regulated. Here, we show that the Snail1 transcription factor represses mouse pericentromeric transcription, acting through the H3K4 deaminase LOXL2. Since Snail1 plays a key role in the epithelial-to-mesenchymal transition (EMT), we analyzed the regulation of heterochromatin transcription in this process. At the onset of EMT, one of the major structural heterochromatin proteins, HP1α, is transiently released from heterochromatin foci in a Snail1/LOXL2-dependent manner, concomitantly with a downregulation of major satellite transcription. Moreover, preventing the downregulation of major satellite transcripts compromised the migratory and invasive behavior of mesenchymal cells. We propose that Snail1 regulates heterochromatin transcription through LOXL2, thus creating the favorable transcriptional state necessary for completing EMT.

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

    NASA Astrophysics Data System (ADS)

    Tiwari, Farindra; Singh, D. K.

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

  6. Celastrol inhibits TGF-β1-induced epithelial–mesenchymal transition by inhibiting Snail and regulating E-cadherin expression

    SciTech Connect

    Kang, Hyereen; Lee, Minjae; Jang, Sung-Wuk

    2013-08-09

    Highlights: •We investigated the effects of celastrol on TGF-β1-induced EMT in epithelial cells. •Celastrol regulates TGF-β1-induced morphological changes and E-cadherin expression. •Celastrol inhibits TGF-β1-induced Snail expression. •Celastrol strongly suppresses TGF-β1-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-β1) 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-β1-mediated the EMT in epithelial cells; however, celastrol markedly inhibited TGF-β1-induced morphologic changes, Snail upregulation, and E-cadherin expression. Migration and invasion assays revealed that celastrol completely inhibited TGF-β1-mediated cellular migration in both cell lines. These findings indicate that celastrol downregulates Snail expression, thereby inhibiting TGF-β1-induced EMT in MDCK and A549 cells. Thus, our findings provide new evidence that celastrol suppresses lung cancer invasion and migration by inhibiting TGF-β1-induced EMT.

  7. The Snail-Induced Sulfonation Pathway in Breast Cancer Metastasis

    DTIC Science & Technology

    2013-07-01

    1 AD_________________ Award Number: W81XWH-11-1-0494 TITLE: The Snail -Induced Sulfonation...REPORT TYPE Annual 3. DATES COVERED 1 July 2012 - 30 June 2013 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-11-1-0494 The Snail -induced...support: 1. Further characterization of Tetracycline inducible WT Snail and mutant Snail vectors and cell lines. 2. Demonstration that the PAPSS2

  8. Induction of VEGFA and Snail-1 by meningitic Escherichia coli mediates disruption of the blood-brain barrier

    PubMed Central

    Yang, Ruicheng; Liu, Wentong; Miao, Ling; Yang, Xiaopei; Fu, Jiyang; Dou, Beibei; Cai, Aoling; Zong, Xin; Tan, Chen; Chen, Huanchun; Wang, Xiangru

    2016-01-01

    Escherichia coli is the most common Gram-negative bacterium that possesses the ability to cause neonatal meningitis, which develops as circulating bacteria penetrate the blood-brain barrier (BBB). However, whether meningitic E. coli could induce disruption of the BBB and the underlying mechanisms are poorly understood. Our current work highlight for the first time the participation of VEGFA and Snail-1, as well as the potential mechanisms, in meningitic E. coli induced disruption of the BBB. Here, we characterized a meningitis-causing E. coli PCN033, and demonstrated that PCN033 invasion could increase the BBB permeability through downregulating and remodeling the tight junction proteins (TJ proteins). This process required the PCN033 infection-induced upregulation of VEGFA and Snail-1, which involves the activation of TLR2-MAPK-ERK1/2 signaling cascade. Moreover, production of proinflammatory cytokines and chemokines in response to infection also promoted the upregulation of VEGFA and Snail-1, therefore further mediating the BBB disruption. Our observations reported here directly support the involvement of VEGFA and Snail-1 in meningitic E. coli induced BBB disruption, and VEGFA and Snail-1 would therefore represent the essential host targets for future prevention of clinical E. coli meningitis. PMID:27588479

  9. Roles of the transcription factors snail and slug during mammary morphogenesis and breast carcinoma progression

    PubMed Central

    Côme, Christophe; Arnoux, Valérie; Bibeau, Frédéric; Savagner, Pierre

    2004-01-01

    The zinc-finger transcription factors snail and slug are involved in different processes controlling cell differentiation and apoptosis. They appear to be involved in tumor progression. Their putative involvement in mammary gland development has not been specifically examined so far. Slug is expressed at a significant level in normal breast and indirect evidence suggests it could be implicated in tubulogenesis. As an anti-apoptotic agent, it could also protect epithelial cells from death during ductal lumen formation and during breast involution. In breast carcinomas, Snail transcription factors have been linked to tumor progression and invasiveness. Possible mechanisms include repression of E-cadherin gene by snail or slug. However, it is not clear how this transcriptional activity is implicated in vivo. Other possible mechanisms involve maintenance of plastic phenotype by slug that could participate in local invasion of ductal carcinomas and interference with apoptotic pathways that could contribute to global tumor growth and radioresistance. These processes probably also involve interactions with estrogen, EGF or c-kit pathways. PMID:15300012

  10. Eosinophilic meningitis risk associated with raw Ampullarium canaliculatus snails consumption.

    PubMed

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

    2011-05-01

    In Taiwan, Angiostrongylus cantonensis infection has been reported in foreign laborers who had consumed raw Ampullarium canaliculatus snails. This study analyzed three foreign laborers who had contracted enzyme-linked immunosorbent assay-confirmed A cantonensis infection while working in Taiwan. All three workers had consumed either roasted snails or raw snails flavored with seasoning while drinking wine. This study investigated possible risk factors for A cantonensis, including naturally occurring A cantonensis in A canaliculatus snails, viability of third-stage A cantonensis larvae in raw seasoned snails and in roasted snails, infectivity of larvae, and effects of alcohol while consuming snails. Positive infection rates in snails from five different irrigation canals in south Taiwan ranged from 12.3% to 29.4% and the average number of motile larvae per infected snail ranged from 36 to 65. The number of motile and coiled larvae in snail meat after 120 minutes seasoning was 93 (27.7%) and 233 (69.3%), respectively. After 20 minutes of roasting, most larvae in the snail meat were dead. The infectivities of motile and coiled larvae from snail meat after 60 minutes seasoning were 53.2% and 33.2%, respectively, and those from snail meat after 5 minutes roasting were 33.2% and 7.0%, respectively. Eating Taiwan A canaliculatus snails raw is extremely risky given their high infection rates and infection intensities. Even after 120 minutes seasoning or after 20 minutes roasting, snail meat should be considered unsafe for human consumption. Finally, experimental rodent studies indicated that consuming alcohol while ingesting larvae does not significantly reduced infectivity.

  11. Aquatic snails, passive hosts of Mycobacterium ulcerans.

    PubMed

    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

    2004-10-01

    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.

  12. 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

  13. Modeling snail breeding in a bioregenerative life support system

    NASA Astrophysics Data System (ADS)

    Kovalev, V. S.; Manukovsky, N. S.; Tikhomirov, A. A.; Kolmakova, A. A.

    2015-07-01

    The discrete-time model of snail breeding consists of two sequentially linked submodels: "Stoichiometry" and "Population". In both submodels, a snail population is split up into twelve age groups within one year of age. The first submodel is used to simulate the metabolism of a single snail in each age group via the stoichiometric equation; the second submodel is used to optimize the age structure and the size of the snail population. Daily intake of snail meat by crewmen is a guideline which specifies the population productivity. The mass exchange of the snail unit inhabited by land snails of Achatina fulica is given as an outcome of step-by-step modeling. All simulations are performed using Solver Add-In of Excel 2007.

  14. 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 Jindřichův Hradec and Třeboň 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.

  15. Can essential oils be used as novel drench treatments for the eggs and juveniles of the pest snail Cornu aspersum in potted plants?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The horticultural trade is an important pathway for the introduction and spread of invasive gastropods because potted plants are essentially portable microhabitats, which protect snails and slugs, especially buried eggs and juveniles, from desiccation and molluscicides. The identification of a drenc...

  16. Survival and behavior of Chinese mystery snails (Bellamya chinensis) in response to simulated water body drawdowns and extended air exposure

    USGS Publications Warehouse

    Unstad, Kody M.; Uden, Daniel R.; Allen, Craig R.; Chaine, Noelle M.; Haak, Danielle M.; Kill, Robert A.; Pope, Kevin L.; Stephen, Bruce J.; Wong, Alec

    2013-01-01

    Nonnative invasive mollusks degrade aquatic ecosystems and induce economic losses worldwide. Extended air exposure through water body drawdown is one management action used for control. In North America, the Chinese mystery snail (Bellamya chinensis) is an invasive aquatic snail with an expanding range, but eradication methods for this species are not well documented. We assessed the ability of B. chinensis to survive different durations of air exposure, and observed behavioral responses prior to, during, and following desiccation events. Individual B. chinensis specimens survived air exposure in a laboratory setting for > 9 weeks, and survivorship was greater among adults than juveniles. Several B. chinensis specimens responded to desiccation by sealing their opercula and/or burrowing in mud substrate. Our results indicate that drawdowns alone may not be an effective means of eliminating B. chinensis. This study lays the groundwork for future management research that may determine the effectiveness of drawdowns when combined with factors such as extreme temperatures, predation, or molluscicides.

  17. Novel pharmacological targets from Indian cone snails.

    PubMed

    Ramasamy, M Santhana; Manikandan, S

    2011-02-01

    The oceans are a source of combinatorial library of unique natural products, 'not found in the terrestrial environment'. Marine invertebrates such as sponges, molluscs, bryozoans, tunicates (Urochordata) and their associated microorganisms are the major representatives of promising bioactive compounds. Among these, the predatory molluscan cone snails have evolved with highly structured small and complex array of peptides (more than 50,000) linked to their prey capture and defence. These peptides have become a valuable source of neuro pharmacological targets as many of them selectively modulate ion channels and transporters. A group of scientists from United States, Europe, Australia, Israel and China have been characterized drugs for neuropathic pain and pharmacological targets from the peptides of a few cone snail species. Several are now in Clinical and preclinical development. Less than 1% of the cono peptides are pharmacologically characterized. India has a diversity of 20-30% of total cone snail species distributed worldwide. A group of Indian Scientists have made promising drug discovery programs from Conus peptides. This review will focus on the Conus peptides from Indian cone snails species, their neuro pharmacological targets and future directions.

  18. Vector snail control in Qalyub, Egypt

    PubMed Central

    van der Schalie, Henry

    1958-01-01

    The author describes a pilot study in vector snail control carried out in 1953-54 by the Bilharziasis Control Project in Qalyub, Egypt. After giving a brief description of the site chosen for the Project—an area of some 5000 acres (2000 hectares) under perennial irrigation—he presents a detailed account of the various snail surveys of the irrigation canals and drains and of the molluscicidal treatment of infested channels. He points out that despite the thoroughness of the surveying and treatment the snails were not completely eliminated from the area and stresses that the high cost of the molluscicide used (copper sulfate) would prohibit its widespread and continual use. He considers, however, that pending the perfection of such long-term bilharziasis control measures as improved sanitation, better treatment facilities, and health education of the public, snail control is of the first importance and determined efforts should be made to find more efficient and cheaper methods of effecting it. PMID:13585074

  19. 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.

  20. miR-34a inhibits pancreatic cancer progression through Snail1-mediated epithelial–mesenchymal transition and the Notch signaling pathway

    PubMed Central

    Tang, Yan; Tang, Yong; Cheng, Ying-sheng

    2017-01-01

    Epithelial–mesenchymal transition (EMT) and Notch signaling are important for the growth and invasion of pancreatic cancer, which is a leading cause of cancer-related deaths worldwide. miR-34a has been shown to play pivotal roles in the progression of several types of cancer. However, little is known about the regulatory mechanisms of miR-34a in pancreatic cancer processes. The aim of this study was to determine whether miR-34a has negative effects on pancreatic cancer and whether these effects are related to EMT and Notch signaling. In vitro, we demonstrated that miR-34a inhibited, while miR-34a inhibitors enhanced, migration and invasion of pancreatic cancer cell lines (PANC-1 and SW-1990).These effects were reversed by Snail1 overexpression or Snail1 shRNA. Furthermore, the anti-apoptotic effects of the miR-34a inhibitors in pancreatic cancer cells were abrogated by Notch1 shRNA. Luciferase reporter assays revealed that the Snail1 and Notch1 genes were direct targets of miR-34a. In vivo, we also demonstrated that miR-34a inhibited pancreatic cancer growth by decreasing Snail1 and Notch1 expression. Therefore, our results indicate that miR-34a inhibits pancreatic cancer progression by post-transcriptionally regulating Snail1 and Notch1 expression. PMID:28145431

  1. Proteomic Analysis of Epithelial to Mesenchymal Transition (EMT) Reveals Cross-talk between SNAIL and HDAC1 Proteins in Breast Cancer Cells*

    PubMed Central

    Palma, Camila de Souza; Grassi, Mariana Lopes; Thomé, Carolina Hassibe; Ferreira, Germano Aguiar; Albuquerque, Daniele; Pinto, Mariana Tomazini; Ferreira Melo, Fernanda Ursoli; Kashima, Simone; Covas, Dimas Tadeu; Pitteri, Sharon J.; Faça, Vitor M.

    2016-01-01

    Epithelial to mesenchymal transition (EMT)1 occurs naturally during embryogenesis, tissue repair, cancer progression, and metastasis. EMT induces cellular and microenvironmental changes resulting in loss of epithelial and acquisition of mesenchymal phenotypes, which promotes cellular invasive and migratory capabilities. EMT can be triggered by extracellular factors, including TGF-β, HGF, and EGF. Overexpression of transcription factors, such as SNAIL, SLUG, ZEB1/2, and TWIST1, also induces EMT and is correlated to cancer aggressiveness. Here, the breast adenocarcinoma cell line MCF7 was transduced with SNAIL to identify specific mechanisms controlled by this transcription factor during EMT. Overexpression of SNAIL led to EMT, which was thoroughly validated by molecular, morphological, and functional experiments. Subcellular proteome enrichment followed by GEL-LC-MS/MS was performed to provide extensive protein fractionation and in-depth proteomic analysis. Quantitative analysis relied on a SILAC strategy, using the invasive breast cancer cell line MDA-MB-231 as a reference for quantitation. Subsets of proteins enriched in each subcellular compartment led to a complementary list of 4289 proteins identified with high confidence. A subset of differentially expressed proteins was validated by Western blot, including regulation in specific cellular compartments, potentially caused by protein translocation. Protein network analysis highlighted complexes involved in cell cycle control and epigenetic regulation. Flow cytometry analysis indicated that SNAIL overexpression led to cell cycle arrest in G0/G1 phases. Furthermore, down-regulation of HDAC1 was observed, supporting the involvement of epigenetic processes in SNAIL-induced EMT. When HDAC1 activity was inhibited, MCF7 not only apparently initiated EMT but also up-regulated SNAIL, indicating the cross-talk between these two proteins. Both HDAC1 inhibition and SNAIL overexpression activated the AKT pathway. These

  2. Proteomic Analysis of Epithelial to Mesenchymal Transition (EMT) Reveals Cross-talk between SNAIL and HDAC1 Proteins in Breast Cancer Cells.

    PubMed

    Palma, Camila de Souza; Grassi, Mariana Lopes; Thomé, Carolina Hassibe; Ferreira, Germano Aguiar; Albuquerque, Daniele; Pinto, Mariana Tomazini; Ferreira Melo, Fernanda Ursoli; Kashima, Simone; Covas, Dimas Tadeu; Pitteri, Sharon J; Faça, Vitor M

    2016-03-01

    Epithelial to mesenchymal transition (EMT)(1) occurs naturally during embryogenesis, tissue repair, cancer progression, and metastasis. EMT induces cellular and microenvironmental changes resulting in loss of epithelial and acquisition of mesenchymal phenotypes, which promotes cellular invasive and migratory capabilities. EMT can be triggered by extracellular factors, including TGF-β, HGF, and EGF. Overexpression of transcription factors, such as SNAIL, SLUG, ZEB1/2, and TWIST1, also induces EMT and is correlated to cancer aggressiveness. Here, the breast adenocarcinoma cell line MCF7 was transduced with SNAIL to identify specific mechanisms controlled by this transcription factor during EMT. Overexpression of SNAIL led to EMT, which was thoroughly validated by molecular, morphological, and functional experiments. Subcellular proteome enrichment followed by GEL-LC-MS/MS was performed to provide extensive protein fractionation and in-depth proteomic analysis. Quantitative analysis relied on a SILAC strategy, using the invasive breast cancer cell line MDA-MB-231 as a reference for quantitation. Subsets of proteins enriched in each subcellular compartment led to a complementary list of 4289 proteins identified with high confidence. A subset of differentially expressed proteins was validated by Western blot, including regulation in specific cellular compartments, potentially caused by protein translocation. Protein network analysis highlighted complexes involved in cell cycle control and epigenetic regulation. Flow cytometry analysis indicated that SNAIL overexpression led to cell cycle arrest in G0/G1 phases. Furthermore, down-regulation of HDAC1 was observed, supporting the involvement of epigenetic processes in SNAIL-induced EMT. When HDAC1 activity was inhibited, MCF7 not only apparently initiated EMT but also up-regulated SNAIL, indicating the cross-talk between these two proteins. Both HDAC1 inhibition and SNAIL overexpression activated the AKT pathway. These

  3. Snail regulated by PKC/GSK-3β pathway is crucial for EGF-induced epithelial-mesenchymal transition (EMT) of cancer cells.

    PubMed

    Liu, Zong-cai; Chen, Xiao-hui; Song, Hai-xing; Wang, Hong-sheng; Zhang, Ge; Wang, Hao; Chen, Dan-yang; Fang, Rui; Liu, Hao; Cai, Shao-hui; Du, Jun

    2014-11-01

    Cancer metastasis is considered a major challenge in cancer therapy. Recently, epidermal growth factor (EGF)/epidermal growth factor receptor (EGFR) signaling has been shown to induce epithelial-mesenchymal transition (EMT) and thereby to promote cancer metastasis. However, the underlying mechanism has not been fully elucidated. We demonstrate that EGF can induce EMT in human prostate and lung cancer cells and thus promote invasion and migration. EGF-induced EMT has been characterized by the cells acquiring mesenchymal spindle-like morphology and increasing their expression of N-cadherin and fibronectin, with a concomitant decrease of E-cadherin. Both protein and mRNA expression of transcription factor Snail rapidly increases after EGF treatment. The knockdown of Snail significantly attenuates EGF-induced EMT, suggesting that Snail is crucial for this process. To determine the way that Snail is accumulated, we demonstrate (1) that EGF promotes the stability of Snail via inhibiting the activity of glycogen synthase kinase 3 beta (GSK-3β), (2) that protein kinase C (PKC) rather than the phosphatidylinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway is responsible for GSK-3β inhibition and (3) that GSK-3β inhibition promotes the transcription of Snail. Taken together, these results reveal that the PKC/GSK-3β signaling pathway controls both the stability and transcription of Snail, which is crucial for EMT induced by EGF in PC-3 and A549 cells. Our study suggests a novel signaling pathway for Snail regulation and provides a better understanding of growth-factor-induced tumor EMT and metastasis.

  4. 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

  5. miR-181b-3p promotes epithelial-mesenchymal transition in breast cancer cells through Snail stabilization by directly targeting YWHAG.

    PubMed

    Yoo, Je-Ok; Kwak, Seo-Young; An, Hyun-Ju; Bae, In-Hwa; Park, Myung-Jin; Han, Young-Hoon

    2016-07-01

    Epithelial-mesenchymal transition (EMT) is essential for increased invasion and metastasis during cancer progression. Among the candidate EMT-regulating microRNAs that we previously identified, miR-181b-3p was found to induce EMT in MCF7 breast cancer cells, as indicated by an EMT-characteristic morphological change, increased invasiveness, and altered expression of an EMT marker. Transfection with a miR-181b-3p inhibitor reduced the expression of mesenchymal markers and the migration and invasion of highly invasive breast cancer cells. miR-181b-3p induced the upregulation of Snail, a master EMT inducer and transcriptional repressor of E-cadherin, through protein stabilization. YWHAG was identified as a direct target of miR-181b-3p, downregulation of which induced Snail stabilization and EMT phenotypes. Ectopic expression of YWHAG abrogated the effect of miR-181b-3p, including Snail stabilization and the promotion of invasion. In situ hybridization and immunohistochemical analyses indicated that YWHAG expression was inversely correlated with the expression of miR-181b-3p and Snail in human breast cancer tissues. Furthermore, transfection with miR-181b-3p increased the frequency of metastatic nodule formation in the lungs of mice in experimental metastasis assays using MDA-MB-231 cells. Taken together, our data suggest that miR-181b-3p functions as a metastasis activator by promoting Snail-induced EMT, and may therefore be a therapeutic target in metastatic cancers.

  6. HOPX hypermethylation promotes metastasis via activating SNAIL transcription in nasopharyngeal carcinoma

    PubMed Central

    Ren, Xianyue; Yang, Xiaojing; Cheng, Bin; Chen, Xiaozhong; Zhang, Tianpeng; He, Qingmei; Li, Bin; Li, Yingqin; Tang, Xinran; Wen, Xin; Zhong, Qian; Kang, Tiebang; Zeng, Musheng; Liu, Na; Ma, Jun

    2017-01-01

    Nasopharyngeal carcinoma (NPC) is characterized by a high rate of local invasion and early distant metastasis. Increasing evidence indicates that epigenetic abnormalities play important roles in NPC development. However, the epigenetic mechanisms underlying NPC metastasis remain unclear. Here we investigate aberrantly methylated transcription factors in NPC tissues, and we identify the HOP homeobox HOPX as the most significantly hypermethylated gene. Consistently, we find that HOXP expression is downregulated in NPC tissues and NPC cell lines. Restoring HOPX expression suppresses metastasis and enhances chemosensitivity of NPC cells. These effects are mediated by HOPX-mediated epigenetic silencing of SNAIL transcription through the enhancement of histone H3K9 deacetylation in the SNAIL promoter. Moreover, we find that patients with high methylation levels of HOPX exhibit poor clinical outcomes in both the training and validation cohorts. In summary, HOPX acts as a tumour suppressor via the epigenetic regulation of SNAIL transcription, which provides a novel prognostic biomarker for NPC metastasis and therapeutic target for NPC treatment. PMID:28146149

  7. Notch1-Snail1-E-cadherin pathway in metastatic hepatocellular carcinoma.

    PubMed

    Wang, Xiao Qi; Zhang, Wu; Lui, Eric L H; Zhu, Yongqiang; Lu, Ping; Yu, Xiaoming; Sun, Jisan; Yang, Sitian; Poon, Ronnie T P; Fan, Sheung Tat

    2012-08-01

    Notch signaling, a critical pathway for tissue development, also contributes to tumorigenesis in many cancers, but its pathological function in liver cancer is not well defined. In our study, Notch1 expression and its clinicopathological parameters were evaluated in 82 human hepatocellular carcinoma (HCC) patients. Plasmid-based siNotch1 shRNA was transiently or stably transfected into metastatic HCC cells and subsequently evaluated for the effects on orthotopic liver tumor metastasis in a mouse model as well as the effects on downstream pathways. Aberrant high expression of Notch1 was significantly associated with metastatic disease parameters in HCC patients, such as tumor-node-metastasis Stages III-IV and tumor venous invasion. Knocking-down Notch1 reduced cell motility in vitro and orthotopic tumor metastasis from the liver to the lung in vivo in a mouse model. In metastatic HCC cells, abnormal expression of Notch1 was associated with increased expression of Snail1 and repressed expression of E-cadherin; the Notch1-Snail1-E-cadherin association can also be found in HCC patient tumors. Inhibition of Notch1 by shRNA abolished Snail1 expression, which further resulted in the re-establishment of repressed E-cadherin in metastatic HCC cells. Thus, abnormal Notch1 expression was strongly associated with HCC metastatic disease, which might be mediated through the Notch1-Snail1-E-cadherin pathway. Knock-down of Notch1 reversed HCC tumor metastasis in a mouse model. Therefore, these data suggest that effective targeting of Notch signaling might also inhibit tumor metastasis.

  8. Unusual snail species involved in the transmission of Fasciola hepatica in watercress beds in central France.

    PubMed

    Dreyfuss, G; Vignoles, P; Abrous, M; Rondelaud, D

    2002-06-01

    Four freshwater pulmonate species (Lymnaea ovata, L. stagnalis, Physa acuta, Planorbis leucostoma) were living in several watercress beds known for their relationships with human cases of fasciolosis, whereas L. truncatula was never found. The aims of these studies were to determine the prevalence of natural infections with Fasciola hepatica in snails and to verify if these species might ensure the full larval development of this trematode (with cercarial shedding) when they were experimentally subjected to F. hepatica only, or to co-infections with an other trematode species. Investigations were so carried out in six snail populations living in watercress beds (including three for P. acuta) and in four others originating from three brooks or a pond (as controls). Snails naturally infected with F. hepatica were found in two watercress beds inhabited by L. ovata (prevalence of infection: 1.4%) and P. leucostoma (0.1%), respectively. The L. ovata from the watercress bed could be infected at a higher size than those from the control population and the prevalence of this infection was greater in the bed population. Similar findings were noted for L. stagnalis. Despite single or dual infections, the results obtained with the four populations of P. acuta were unsuccessful. In contrast, the co-infections of young P. leucostoma with Paramphistomum daubneyi and F. hepatica resulted in the shedding of some F. hepatica cercariae. According to the authors, the occurrence of fasciolosis in these watercress beds would be the consequence of frequent natural encounters between parasite and snails (L. ovata, L. stagnalis), or of co-infections with P. daubneyi and F. hepatica (P. leucostoma). In watercress beds only colonized by P. acuta, a lymnaeid species would have ensured the larval development of F. hepatica but it would have been eliminated by P. acuta, as this last species was known to be invasive and could colonize open drainage ditches on siliceous soil.

  9. 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

  10. The Snail-Induced Sulfonation Pathway in Breast Cancer Metastasis

    DTIC Science & Technology

    2014-09-01

    AD_________________ Award Number: W81XWH-11-1-0494   TITLE: The Snail -Induced Sulfonation... Snail -Induced Sulfonation Pathway in Breast Cancer Metastasis 5b. GRANT NUMBER W81XWH-11-1-0494 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dr...provided funding for a 3-year project that has resulted in fundamental new insights into how the transcription factor Snail can control gene

  11. 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.

  12. Biogeography: molecular trails from hitch-hiking snails.

    PubMed

    Gittenberger, Edmund; Groenenberg, Dick S J; Kokshoorn, Bas; Preece, Richard C

    2006-01-26

    Darwin was fascinated by the transportation of land snails across great swathes of open ocean by birds--he even immersed snails in sea water to see how long they would survive. Here we follow a molecular phylogenetic trail that reveals the incredible transequatorial dispersal of the land snail Balea from Europe to the Azores and the Tristan da Cunha islands, and back again. This long-distance dispersal is unexpected for what are proverbially considered the most pedestrian of creatures.

  13. STC2 promotes head and neck squamous cell carcinoma metastasis through modulating the PI3K/AKT/Snail signaling

    PubMed Central

    Yang, Shuwen; Ji, Qinghai; Chang, Bin; Wang, Yan; Zhu, Yongxue; Li, Duanshu; Huang, Caiping; Wang, Yulong; Sun, Guohua; Zhang, Ling; Guan, Qing; Xiang, Jun; Wei, Wenjun; Lu, Zhongwu; Liao, Tian; Meng, Jiao; Wang, Ziliang; Ma, Ben; Zhou, Li; Wang, Yu; Yang, Gong

    2017-01-01

    The mammalian peptide hormone stanniocalcin 2 (STC2) plays an oncogenic role in many human cancers. However, the exact function of STC2 in human head and neck squamous cell carcinoma (HNSCC) is unclear. We aimed to examine the function and clinical significance of STC2 in HNSCC. Using in vitro and in vivo assays, we show that overexpression of STC2 suppressed cell apoptosis, promoted cell proliferation, migration, invasion, and cell cycle arrest at the G1/S transition. By contrast, silencing of STC2 inhibited these activities. We further show that STC2 upregulated the phosphorylation of AKT and enhanced HNSCC metastasis via Snail-mediated increase of vimentin and decrease of E-cadherin. These responses were blocked by silencing of STC2/Snail expression or inhibition of pAKT activity. Furthermore, clinical data indicate that high STC2 expression was associated with high levels of pAKT and Snail in tumor samples from HNSCC patients with regional lymph node metastasis (P < 0.01). Thus, we conclude that STC2 controls HNSCC metastasis via the PI3K/AKT/Snail signaling axis and that targeted therapy against STC2 may be a novel strategy to effectively treat patients with metastatic HNSCC. PMID:27863406

  14. Interactions among invaders: community and ecosystem effects of multiple invasive species in an experimental aquatic system.

    PubMed

    Johnson, Pieter T J; Olden, Julian D; Solomon, Christopher T; Vander Zanden, M Jake

    2009-02-01

    With ecosystems increasingly supporting multiple invasive species, interactions among invaders could magnify or ameliorate the undesired consequences for native communities and ecosystems. We evaluated the individual and combined effects of rusty crayfish (Orconectes rusticus) and Chinese mystery snails [Bellamya (=Cipangopaludina) chinensis] on native snail communities (Physa, Helisoma and Lymnaea sp.) and ecosystem attributes (algal chlorophyll a and nutrient concentrations). Both invaders are widespread in the USA and commonly co-occur within northern temperate lakes, underscoring the importance of understanding their singular and joint effects. An outdoor mesocosm experiment revealed that while the two invaders had only weakly negative effects upon one another, both negatively affected the abundance and biomass of native snails, and their combined presence drove one native species to extinction and reduced a second by >95%. Owing to its larger size and thicker shell, adult Bellamya were protected from crayfish attack relative to native species (especially Physa and Lymnaea), suggesting the co-occurrence of these invaders in nature could have elevated consequences for native communities. The per capita impacts of Orconectes (a snail predator) on native snails were substantially greater than those of Bellamya (a snail competitor). Crayfish predation also had a cascading effect by reducing native snail biomass, leading to increased periphyton growth. Bellamya, in contrast, reduced periphyton biomass, likely causing a reduction in growth by native lymnaeid snails. Bellamya also increased water column N:P ratio, possibly because of a low P excretion rate relative to native snail species. Together, these findings highlight the importance of understanding interactions among invasive species, which can have significant community- and ecosystem-level effects.

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

    PubMed Central

    Najarian, H. H.

    1961-01-01

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

  16. Glycogen synthase kinase-3 beta regulates Snail and β-catenin expression during Fas-induced epithelial-mesenchymal transition in gastrointestinal cancer.

    PubMed

    Zheng, Haoxuan; Li, Wenjing; Wang, Yadong; Liu, Zhizhong; Cai, Yidong; Xie, Tingting; Shi, Meng; Wang, Zhiqing; Jiang, Bo

    2013-08-01

    Fas signalling has been shown to induce the epithelial-mesenchymal transition (EMT) to promote gastrointestinal (GI) cancer metastasis, but its mechanism of action is still unknown. The effects of Fas-ligand (FasL) treatment and inhibition of Fas signalling on GI cancer cells were tested using invasion assay, immunofluorescence, immunoblot, Reverse Transcription Polymerase Chain Reaction (RT-PCR), quantitative Real-time PCR (qRT-PCR), immunoprecipitation and luciferase reporter assay. Immunohistochemistry was used to analyse the EMT-associated molecules in GI cancer specimens. FasL treatment inhibited E-cadherin transcription by upregulation of Snail in GI cancer cells. The nuclear expression and transcriptional activity of Snail and β-catenin were increased by inhibitory phosphorylation of glycogen synthase kinase-3 beta (GSK-3β) at Ser9 by FasL-induced extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signalling. Snail associated with β-catenin in the nucleus and, thus, increased β-catenin transcriptional activity. Evaluation of human GI cancer specimens showed that the expression of FasL, phospho-GSK-3β, Snail and β-catenin increase during GI cancer progression. An EMT phenotype was shown to correlate with an advanced cancer stage, and a non-EMT phenotype significantly correlated with a better prognosis. Collectively, these data indicate that GSK-3β regulates Snail and β-catenin expression during Fas-induced EMT in gastrointestinal cancer.

  17. Development and characterization of 17 polymorphic microsatellite loci in the faucet snail, Bithynia tentaculata (Gastroposa: Caenogastropoda; Bithyniidae)

    USGS Publications Warehouse

    Henningsen, Justin P.; Lance, Stacey L.; Jones, Kenneth L.; Hagen, Chris; Laurila, Joshua; Cole, Rebecca A.; Perez, Kathryn E.

    2010-01-01

    Bithynia tentaculata (Linnaeus, 1758), a snail native to Europe, was introduced into the US Great Lakes in the 1870's and has spread to rivers throughout the Northeastern US and Upper Mississippi River (UMR). Trematode parasites, for which B. tentaculata is a host, have also been introduced and are causing widespread waterfowl mortality in the UMR. Waterfowl mortality is caused by ingestion of trematode-infected B. tentaculata or insects infected with parasites released from the snails. We isolated and characterized 17 microsatellite loci from the invasive faucet snail, B. tentaculata (Gastropoda: Caenogastropoda: Bithyniidae). Loci were screened in 24 individuals of B. tentaculata. The number of alleles per locus ranged from 2 to 6, observed heterozygosity ranged from 0.050 to 0.783, and the probability of identity values ranged from 0.10 to 0.91. These new loci provide tools for examining the origin and spread of invasive populations in the US and management activities to prevent waterfowl mortality.

  18. Genetic structure of faucet snail, Bithynia tentaculata populations in North Americal based on microsattelite markers

    USGS Publications Warehouse

    Perez, Kathryn E.; Werren, Rebecca L.; Lynum, Christopher A.; Hartman, Levi A.; Majoros, Gabor; Cole, Rebecca A.

    2016-01-01

    Bithynia tentaculata is believed to have been extirpated from North America during the last glacial maximum. It was reintroduced into North America via the Great Lakes basin in the 1800’s and has recently been expanding its geographic range. This snail serves as intermediate host for three trematodes that cause extensive recurring morbidity and mortality events in migratory water birds along the Mississippi River. Using twelve microsatellite loci for ~200 individual snails from 11 populations in North America and Europe, we examined one of the three major geographic regions from which founding populations into the Great Lakes typically originate. Our data supports a single recolonization of North America into the Great Lakes Basin followed by subsequent introduction events from the Great Lakes to other large watersheds in North America. However, additional watersheds in Europe require sampling to confirm this result. No populations with genetic signatures indicative of North American glacial relics were found. The initial invasion of North America was likely not from the Ponto-Caspian basin, the usual source of freshwater invasive species to the Laurentian Great Lakes.

  19. Apigenin inhibits NF-κB and Snail signaling, EMT and metastasis in human hepatocellular carcinoma

    PubMed Central

    Zhong, Wei-long; Chen, Shuang; Gu, Wen-guang; Wang, Wei; Zhang, Chun-hong; Liu, Yan-rong; Liu, Hui-juan; Zhang, Qiang; Guo, Yuan-qiang; Sun, Tao; Yang, Cheng

    2016-01-01

    Apigenin is a naturally occurring compound with anti-inflammatory, antioxidant, and anticancer properties. In this study, we investigated the effects of apigenin on migration and metastasis in experimental human hepatocellular carcinoma (HCC) cell lines in vitro and in vivo. Apigenin dose-dependently inhibited proliferation, migration, and invasion by PLC and Bel-7402 human HCC cells. It also suppressed tumor growth in PLC cell xenografts without altering body weight, thereby prolonging survival. Apigenin reduced Snai1 and NF-κB expression, reversed increases in epithelial-mesenchymal transition (EMT) marker levels, increased cellular adhesion, regulated actin polymerization and cell migration, and inhibited invasion and migration by HCC cells. Apigenin may therefore inhibit EMT by inhibiting the NF-κB/Snail pathway in human HCC. PMID:27203387

  20. 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…

  1. 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

  2. Microhabitats within venomous cone snails contain diverse actinobacteria.

    PubMed

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

    2009-11-01

    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.

  3. The Mitochondrial Genome of the Venomous Cone Snail Conus consors

    PubMed Central

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

    2012-01-01

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

  4. 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

  5. The mitochondrial genome of the venomous cone snail Conus consors.

    PubMed

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

    2012-01-01

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

  6. An evaluation of techniques used in estimating snail populations

    PubMed Central

    Hairston, Nelson G.; Hubendick, Bengt; Watson, John M.; Olivier, Louis J.

    1958-01-01

    No uniform method, applicable to all situations, can be developed for the quantitative study of bilharziasis vector snail populations. The selection of survey technique and sampling device depends on the objectives of the study, the circumstances in which the work is carried out, the nature of the habitat and the resources available. The various techniques used in obtaining snail-population estimates are divided into two categories—direct methods and indirect methods. The former involve the collection of snails from a specified habitat or for a specified period of time, while the latter include techniques, such as snail marking and palm-leaf traps, in which the snails are not obtained through the efforts of a collector. Each method and device is described in detail, and its suitability under various conditions is discussed. PMID:13596889

  7. Investigating Invasives

    ERIC Educational Resources Information Center

    Lightbody, Mary

    2008-01-01

    Invasive species, commonly known as "invasives," are nonnative plants, animals, and microbes that completely take over and change an established ecosystem. The consequences of invasives' spread are significant. In fact, many of the species that appear on the Endangered Species list are threatened by invasives. Therefore, the topic of invasive…

  8. 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.

  9. 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

  10. Amphiregulin induces human ovarian cancer cell invasion by down-regulating E-cadherin expression.

    PubMed

    So, Wai-Kin; Fan, Qianlan; Lau, Man-Tat; Qiu, Xin; Cheng, Jung-Chien; Leung, Peter C K

    2014-11-03

    Aberrant epidermal growth factor receptor (EGFR) activation is associated with ovarian cancer progression. In this study, we report that the EGFR ligand amphiregulin (AREG) stimulates cell invasion and down-regulates E-cadherin expression in two human ovarian cancer cell lines, SKOV3 and OVCAR5. In addition, AREG increases the expression of transcriptional repressors of E-cadherin including SNAIL, SLUG and ZEB1. siRNA targeting SNAIL or SLUG abolishes AREG-induced cell invasion. Moreover, ERK1/2 and AKT pathways are involved in AREG-induced E-cadherin down-regulation and cell invasion. Finally, we show that three EGFR ligands, AREG, epidermal growth factor (EGF) and transforming growth factor-α (TGF-α), exhibit comparable effects in down-regulating E-cadherin and promoting cell invasion. This study demonstrates that AREG induces ovarian cancer cell invasion by down-regulating E-cadherin expression.

  11. Intoxication and biochemical responses of freshwater snail Bellamya aeruginosa to ethylbenzene.

    PubMed

    Zheng, Shimei; Zhou, Qixing

    2017-01-01

    No acute toxic data of ethylbenzene on gastropod is available in literature. In the present study, the acute toxicity of ethylbenzene was assessed on a freshwater snail Bellamya aeruginosa, which was exposed to ethylbenzene concentration from 1 to 100 mg/L for 96 h. No mortality occurred, but a manifestation of intoxication (distress syndrome) was observed in part of exposed snails, and meanwhile, another part was moved normally. The distress syndrome showed clear dose- and time-dependent effects, and the 96-h EC50 value for distress syndrome was 13.3 mg/L in snail. The biochemical responses induced by ethylbenzene to the snail, including acetylcholinesterase (AChE) in the whole body and superoxide dismutase (SOD), catalase (CAT), glutathione S-transferases (GST), and reduced glutathione (GSH) in the hepatopancreas, were evaluated both for distressed snail and moved snail. The AChE activity of distressed snail was all inhibited more than 45 %, and the inhibition of AChE activity in the moved snail was all less than 30 % and more than 20 %, demonstrating that ethylbenzene exerted nervous toxicity to both distressed snail and moved snail. Meanwhile, the difference for AChE activity between the two different response snails was significant. Among the antioxidant biomarkers (SOD, CAT, GST, and GSH), only GST displayed significant difference between the distressed snail and moved snail. However, the activities of enzymes (SOD, CAT, and GST) in the moved snail were greater than those in the distressed snail, no matter significantly or insignificantly, which indicated that the ability of antioxidant defense in the distressed snail was weaker than that in the moved snail. The findings here reported manifest that ethylbenzene exerted nervous toxicity to snail, and the snail with intoxication response (distress syndrome) presented larger inhibition on AChE activity and weaker antioxidant ability in comparison with the moved snail.

  12. Crawling beneath the free surface: Water snail locomotion

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

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

  13. Invasive Species

    EPA Pesticide Factsheets

    Invasive species have significantly changed the Great Lakes ecosystem. An invasive species is a plant or animal that is not native to an ecosystem, and whose introduction is likely to cause economic, human health, or environmental damage.

  14. Invasive Candidiasis

    MedlinePlus

    ... Invasive candidiasis is an infection caused by a yeast (a type of fungus) called Candida . Unlike Candida ... mouth and throat (also called “thrush”) or vaginal “yeast infections,” invasive candidiasis is a serious infection that ...

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

    PubMed

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

    2014-01-01

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

  16. TRIM16 suppresses the progression of prostate tumors by inhibiting the Snail signaling pathway

    PubMed Central

    Qi, Li; Lu, Zhong; Sun, Yong-Hong; Song, Hai-Tao; Xu, Wei-Kang

    2016-01-01

    Prostate carcinoma is a devastating disease which is characterized by insidious early symptoms, rapid progression and a poor prognosis. Tripartite motif-containing protein 16 (TRIM16) was identified as an estrogen- and antiestrogen-regulated gene in epithelial cells stably expressing estrogen receptors. The protein encoded by this gene contains two B-box domains and a coiled-coiled region that are characteristic of the B-box zinc finger protein family. Proteins belonging to this family have been reported to be involved in a variety of biological processes including cell growth, differentiation and pathogenesis. TRIM16 expression has been detected in most tissues. However, the funtions of this gene remain to be elucidated. In the present study, immunohistochemical staining revealed that the expression of TRIM16 was decreased in prostate adenocarcinoma compared with that in normal prostate tissues. The patients with high TRIM16-expressing tumors had a significantly greater survival than those with low TRIM16-expressing tumors. Western blot analysis showed that TRIM16 was downregulated in distant metastatic cancer tissues compared with that in non-distant metastatic cancer tissues. The overexpression of TRIM16 inhibited the migration and invasion of prostate cancer cells as well as inhibiting the epithelial-to-mesenchymal transition process, whereas TRIM16 depletion enhanced these processes. Moreover, TRIM16 inhibited the Snail signaling pathway. The silencing of Snail by small interfering RNA was performed in order to determine the role of Snail in the TRIM16-mediated tumor phenotype. Taken together, these findings suggest that TRIM16 may be an important molecular target which may aid in the design of novel therapeutic agents for prostate cancer. PMID:27748839

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

    PubMed Central

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

    2014-01-01

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

  18. 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.

  19. 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

  20. Snails, stable iostopes, and southwestern desert paleoclimates

    SciTech Connect

    Sharpe, S.E.; Whelan, J.F.; Forester, R.M.; Burdett, J.

    1995-09-01

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

  1. Prey-tracking behavior in the invasive terrestrial planarian Platydemus manokwari (Platyhelminthes, Tricladida).

    PubMed

    Iwai, Noriko; Sugiura, Shinji; Chiba, Satoshi

    2010-11-01

    Platydemus manokwari is a broadly distributed invasive terrestrial flatworm that preys heavily on land snails and has been credited with the demise of numerous threatened island faunas. We examined whether P. manokwari tracks the mucus trails of land snail prey, investigated its ability to determine trail direction, and evaluated prey preference among various land snail species. A plastic treatment plate with the mucus trail of a single species and a control plate without the trail were placed side by side at the exit of cages housing P. manokwari. All trials were then videotaped overnight. The flatworms moved along plates with mucus trails, but did not respond to plates without trails, blank control (distilled water), or with conspecific flatworm trails. When presented at the midpoint of a snail mucus trail, the flatworms followed the trail in a random direction. The flatworms showed a preference when choosing between two plates, each with a mucus trail of different land snail species. Our results suggest that P. manokwari follows snail mucus trails based on chemical cues to increase the chance of encountering prey; however, trail-tracking behavior showed no directionality.

  2. Prey-tracking behavior in the invasive terrestrial planarian Platydemus manokwari (Platyhelminthes, Tricladida)

    NASA Astrophysics Data System (ADS)

    Iwai, Noriko; Sugiura, Shinji; Chiba, Satoshi

    2010-11-01

    Platydemus manokwari is a broadly distributed invasive terrestrial flatworm that preys heavily on land snails and has been credited with the demise of numerous threatened island faunas. We examined whether P. manokwari tracks the mucus trails of land snail prey, investigated its ability to determine trail direction, and evaluated prey preference among various land snail species. A plastic treatment plate with the mucus trail of a single species and a control plate without the trail were placed side by side at the exit of cages housing P. manokwari. All trials were then videotaped overnight. The flatworms moved along plates with mucus trails, but did not respond to plates without trails, blank control (distilled water), or with conspecific flatworm trails. When presented at the midpoint of a snail mucus trail, the flatworms followed the trail in a random direction. The flatworms showed a preference when choosing between two plates, each with a mucus trail of different land snail species. Our results suggest that P. manokwari follows snail mucus trails based on chemical cues to increase the chance of encountering prey; however, trail-tracking behavior showed no directionality.

  3. Hydrocyclonic separation of invasive New Zealand mudsnails from an aquaculture water source

    USGS Publications Warehouse

    Nielson, R. Jordan; Moffitt, Christine M.; Watten, Barnaby J.

    2012-01-01

    Invasive New Zealand mudsnails (Potamopyrgus antipodarum, NZMS) have infested freshwater aquaculture facilities in the western United States and disrupted stocking or fish transportation activities because of the risk of transporting NZMS to naive locations. We tested the efficacy of a gravity-fed, hydrocyclonicseparation system to remove NZMS from an aquaculture water source at two design flows: 367 L/min and 257 L/min. The hydrocyclone effectively filtered all sizes of snails (including newly emerged neonates) from inflows. We modeled cumulative recovery of three sizes of snails, and determined that both juvenile and adult sized snails were transported similarly through the filtration system, but the transit of neonates was faster and similar to the transport of water particles. We found that transit times through the filtration system were different between the two flows regardless of snail size, and the hydrocyclone filter operated more as a plug flow system with dispersion, especially when transporting and removing the larger sized adult and juvenile sized snails. Our study supports hydrocyclonic filtration as an important tool to provide snail free water for aquaculture operations that require uninfested water sources.

  4. Epithelial-Mesenchymal Transition Markers β-catenin, Snail, and E-Cadherin do not Predict Disease Free Survival in Prostate Adenocarcinoma: a Prospective Study.

    PubMed

    Ipekci, Tumay; Ozden, Ferhat; Unal, Betul; Saygin, Caner; Uzunaslan, Didem; Ates, Erhan

    2015-09-01

    Current methods for diagnosis and staging of prostate adenocarcinoma are not sensitive enough to distinguish between patients with indolent disease and those that should receive radical treatment. Epithelial-mesenchymal transition (EMT) is a well-characterized process involved in tumor invasion and metastasis. The aim of this study is to analyze the expression of β-catenin, Snail, and E-cadherin in prostate cancer patients with prospective evaluation of their value in predicting disease-free survival (DFS). One-hundred-and-three consecutive prostate carcinoma patients who underwent radical prostatectomy and 35 patients with benign prostate hyperplasia (BPH) were enrolled. Age, initial PSA level, tumor size and clinical stage were documented for adenocarcinoma patients and they were enrolled in active surveillance with serum PSA levels. Recurrence was defined as PSA level of ≥ 0.2 ng/ml on at least 2 occasions over a 2-month period. Immunohistochemical staining intensity was scored as negative, weakly positive, moderately positive, and strongly positive. For Snail and β-catenin immunoreaction, the tumors were considered nuclear positive when more than 5 % of the nuclei of tumor cells were positively stained. Patients with prostate cancer had weaker β-catenin (p < 0.0001), Snail (p = 0.006), and E-cadherin (p = 0.02) staining when compared to BPH patients and the frequency of nuclear positivity for β-catenin and Snail were higher in adenocarcinoma group (p < 0.0001). Increased expression and nuclear positivity of β-catenin were associated with advanced stage (p = 0.012 and p = 0.003) and higher tumor volume (p = 0.013 and p = 0.002). Additionally, patients with increased Snail expression had higher Gleason scores and tumor volume at presentation (p = 0.008 and p = 0.004). However, there were no significant DFS differences in adenocarcinoma patients who did and did not have β-catenin, Snail, and E-cadherin expression as assessed with log-rank test. Expressions

  5. History or current selection? A molecular analysis of 'area effects' in the land snail Cepaea nemoralis.

    PubMed Central

    Davison, A; Clarke, B

    2000-01-01

    We have used molecular variation in microsatellite and mitochondrial DNA to throw light on the origins of enigmatic geographical patterns, known as 'area effects', in the shell polymorphisms of the land snail Cepaea nemoralis. Our aim was to assess the relative importance of recent selection and historical events in the formation of these patterns. On the Marlborough Downs in Wiltshire, England, the 'type locality' for area effects, the frequencies of microsatellites are significantly associated with the frequencies of alleles for shell banding. A less clear association is found between microsatellites and shell colour. Mitochondrial haplotypes show no significant relationships. Although the correlated geographical patterns could be the results of random genetic drift from an initially uniform array of populations, the magnitudes of the patterns, and of the correlations between them, seem too strong to have arisen by drift since the last glaciation. Our results suggest that invasions from refugia have been the most important factors in forming area effects. PMID:10983823

  6. 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

  7. 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

  8. JianPi JieDu Recipe Inhibits Epithelial-to-Mesenchymal Transition in Colorectal Cancer through TGF-β/Smad Mediated Snail/E-Cadherin Expression

    PubMed Central

    Liu, Xuan; Deng, Wanli; Chai, Ni; Feng, Yuanyuan; Zhou, Lihong; Sui, Hua; Li, Chunpu; Sun, Xiaoting

    2017-01-01

    JPJD was an ideal alternative traditional Chinese medicine compound in the prevention and treatment of CRC, but its underlying mechanisms has not been fully elucidated. In this study, we demonstrated in vitro that TGF-β-induced EMT promoted the invasion and metastasis of CRC cells, reduced the expression of E-cadherin, and elevated the expression of Vimentin. However, JPJD could inhibit the invasive and migratory ability of TGF-β-stimulated CRC cells in a concentration-dependent manner through increasing the expression of E-cadherin and repressing the expression of Vimentin, as well as the inhibition of TGF-β/Smad signaling pathway. Meanwhile, JPJD reduced the transcriptional activities of EMT-associated factors Snail and E-cadherin during the initiation of TGF-β-induced EMT. In vivo, the results demonstrated that JPJD can significantly inhibit the liver and lung metastasis of orthotopic CRC tumor in nude mice, as well as significantly prolonging the survival time of tumor-bearing in a dose-dependent manner. Additionally, JPJD can upregulate the expression of E-cadherin and Smad2/3 in the cytoplasm and downregulate the expression of Vimentin, p-Smad2/3, and Snail in the orthotopic CRC tumor tissues. In conclusions, our new findings provided evidence that JPJD could inhibit TGF-β-induced EMT in CRC through TGF-β/Smad mediated Snail/E-cadherin expression. PMID:28299321

  9. 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

  10. Parallel evolution of passive and active defence in land snails

    PubMed Central

    Morii, Yuta; Prozorova, Larisa; Chiba, Satoshi

    2016-01-01

    Predator-prey interactions are major processes promoting phenotypic evolution. However, it remains unclear how predation causes morphological and behavioural diversity in prey species and how it might lead to speciation. Here, we show that substantial divergence in the phenotypic traits of prey species has occurred among closely related land snails as a result of adaptation to predator attacks. This caused the divergence of defensive strategies into two alternatives: passive defence and active defence. Phenotypic traits of the subarctic Karaftohelix land snail have undergone radiation in northeast Asia, and distinctive morphotypes generally coexist in the same regions. In these land snails, we documented two alternative defence behaviours against predation by malacophagous beetles. Furthermore, the behaviours are potentially associated with differences in shell morphology. In addition, molecular phylogenetic analyses indicated that these alternative strategies against predation arose independently on the islands and on the continent suggesting that anti-predator adaptation is a major cause of phenotypic diversity in these snails. Finally, we suggest the potential speciation of Karaftohelix snails as a result of the divergence of defensive strategies into passive and active behaviours and the possibility of species radiation due to anti-predatory adaptations. PMID:27833102

  11. Antioxidants and oxidative stress in Helix pomatia snails during estivation.

    PubMed

    Nowakowska, Anna; Swiderska-Kołacz, Grazyna; Rogalska, Justyna; Caputa, Michał

    2009-11-01

    Estivation enables land snails to survive a prolonged dryness but the return to active state imposes conditions of oxidative stress on internal organs due to a transient large increase in oxygen consumption, which augments mitochondrial production of reactive oxygen species. Therefore, activities of antioxidant enzymes, concentrations of reduced glutathione (GSH) and TBARS as an index of lipid peroxidation, were evaluated in Helix pomatia snails (i) during summer activity, (ii) during estivation, which was induced experimentally, (iii) at the start of arousal from estivation, and (iv) being aroused for 24 h. Estivation induced significant decreases in activity of catalase in the kidney and hepatopancreas and glutathione peroxidase in the kidney. Activity of glutathione reductase was unaffected by estivation/arousal cycle. Summer-active and estivating snails maintained high activity of glutathione transferase. Concentration of GSH was organ-dependent and was positively affected by estivation. Lack of increase in TBARS concentration during estivation/arousal cycle suggests that antioxidant defence system of H. pomatia snails is highly efficacious. In conclusion, permanent maintenance of relatively high activities of the antioxidant enzymes and the high concentration of GSH in H. pomatia snails indicate that they have well-developed strategy of defence against oxidative injury.

  12. miR-486-5p suppresses prostate cancer metastasis by targeting Snail and regulating epithelial–mesenchymal transition

    PubMed Central

    Zhang, Xiaoguang; Zhang, Tong; Yang, Kuo; Zhang, Minghao; Wang, Keming

    2016-01-01

    The most common cause of death from prostate cancer (PCa) is metastases. There is an increasing body of evidence that microRNAs play an important role in the development of PCa by regulating target genes involved in tumor metastasis. Here, we identified that expression of miR-486-5p was decreased in metastatic C4-2 cells compared to non-metastatic LNCaP cells. Further validation in clinical samples showed that miR-486-5p expression was significantly decreased in metastatic PCa tissues compared to localized PCa tissues. Functional studies demonstrated that increased miR-486-5p expression can suppress cell migration and the invasive ability of C4-2 cells. Moreover, Snail, a key regulator of the epithelial–mesenchymal transition, was verified as a target gene of miR-486-5p. In conclusion, these findings suggest that miR-486-5p plays a suppressive role in mediating the migration and invasion of PCa by directly suppressing the protein expression of Snail and may provide a potential therapeutic target for the disease. PMID:27877055

  13. 75 FR 35424 - Endangered and Threatened Wildlife and Plants; Proposed Reclassification of the Tulotoma Snail...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-22

    ...; Proposed Reclassification of the Tulotoma Snail From Endangered to Threatened AGENCY: Fish and Wildlife...), propose to reclassify the tulotoma snail (Tulotoma magnifica) from endangered to threatened, under the... no longer correctly reflects the status of this snail. We have documented a substantial...

  14. 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

  15. Rapid transcription fosters coordinate snail expression in the Drosophila embryo.

    PubMed

    Boettiger, Alistair Nicol; Levine, Michael

    2013-01-31

    Transcription is commonly held to be a highly stochastic process, resulting in considerable heterogeneity of gene expression among the different cells in a population. Here, we employ quantitative in situ hybridization methods coupled with high-resolution imaging assays to measure the expression of snail, a developmental patterning gene necessary for coordinating the invagination of the mesoderm during gastrulation of the Drosophila embryo. Our measurements of steady-state mRNAs suggest that there is very little variation in snail expression across the different cells that make up the mesoderm and that synthesis approaches the kinetic limits of Pol II processivity. We propose that rapid transcription kinetics and negative autoregulation are responsible for the remarkable homogeneity of snail expression and the coordination of mesoderm invagination.

  16. MTA3 regulates CGB5 and Snail genes in trophoblast

    SciTech Connect

    Chen, Ying; Miyazaki, Jun; Nishizawa, Haruki; Kurahashi, Hiroki; Leach, Richard; 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 β-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

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

    PubMed

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

    2003-10-01

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

  18. By inhibiting snail signaling and miR-23a-3p, osthole suppresses the EMT-mediated metastatic ability in prostate cancer

    PubMed Central

    Wen, Yu-Ching; Lee, Wei-Jiunn; Tan, Peng; Yang, Shun-Fa; Hsiao, Michael; Lee, Liang-Ming; Chien, Ming-Hsien

    2015-01-01

    Here we showed that Osthole, 7-methoxy-8-(3-methyl-2-butenyl) coumarin, a bioactive coumarin derivative extracted from medicinal plants, inhibited migration, invasion, epithelial to mesenchymal transition (EMT) in androgen-independent prostate cancer (AIPC) cells in vitro and metastasis of AIPC in vivo. In patients, high Snail levels were correlated with a higher histological Gleason sum and poor survival rates. Osthole inhibited the TGF-β/Akt/MAPK pathways, reduced Snail-DNA-binding activity and induced E-cadherin. We found that osthole decreased miR-23a-3p. Ectopic miR-23a-3p suppressed E-cadherin 3′ untranslated region reporter activity and E-cadherin expression, and relieved the motility suppression caused by osthole treatment. PMID:26110567

  19. 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.

  20. Effects of trematode parasitism on the shell morphology of snails from flow and nonflow environments.

    PubMed

    Gustafson, Kyle D; Bolek, Matthew G

    2016-03-01

    The primary function of the gastropod shell is protection. However, shells that function well in one environment may be maladaptive in another. Upon infection, the snail shell protects internal parasites and it is to the parasite's advantage to optimize, or not interfere with, shell functionality. However, parasites, particularly trematodes, are often pathogenic and it is not clear if parasitism will induce environment-dependent or -independent changes to gastropod shells. We conducted a field study and a complementary laboratory experiment to examine the effects of trematode parasitism on shell characteristics (shape, size, and crush resistance) of Physa acuta snails in flow and nonflow environments using geometric morphometrics and crush assays. Field results indicate wetland (nonflow) snails had large, crush resistant shells with narrow apertures and tall spires. In contrast, stream (flow) snails had small, weak shells with wide apertures and short spires. Parasitism had no apparent effect on the crush resistance of wetland snails but significantly reduced the crush resistance of stream snails. Parasitism had no significant effect on overall shell shape in stream or wetland snails. Similar to the results of our field study, nonflow tank snails had significantly more crush resistant shells than flow tank snails. Additionally, the shapes of flow and nonflow tank snails significantly differed where nonflow tank snails resembled wetland snails and flow tank snails resembled stream snails. For laboratory snails, parasitism reduced crush resistance regardless of flow/nonflow treatment. Our results demonstrate that habitat and/or flow treatment was the primary factor affecting P. acuta shell morphology and that trematode parasitism played a secondary role.

  1. Global assessment of schistosomiasis control over the past century shows targeting the snail intermediate host works best

    USGS Publications Warehouse

    Sokolow, Susanne H.; Wood, Chelsea L.; Jones, Isabel J.; Swartz, Scott J.; Lopez, Melina; Hsieh, Michael H.; Lafferty, Kevin D.; Kuris, Armand M.; Rickards, Chloe; De Leo, Giulio A.

    2016-01-01

    Snail control has been the most effective way to reduce schistosomiasis prevalence. Despite evidence that snail control leads to long-term disease reduction and elimination, most current schistosomiasis control efforts emphasize MDA using praziquantel over snail control. Combining drug-based control programs with affordable snail control seems the best strategy for eliminating schistosomiasis.

  2. 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

    ... Snail, Community of Los Osos, San Luis Obispo County, CA AGENCY: U.S. Fish and Wildlife Service...'' of the federally endangered Morro shoulderband snail (= banded dune snail; Helminthoglypta walkeriana... mitigate project activities that are likely to result in take of the Morro shoulderband snail as...

  3. The long non-coding RNA LINC01013 enhances invasion of human anaplastic large-cell lymphoma.

    PubMed

    Chung, I-Hsiao; Lu, Pei-Hsuan; Lin, Yang-Hsiang; Tsai, Ming-Ming; Lin, Yun-Wen; Yeh, Chau-Ting; Lin, Kwang-Huei

    2017-03-22

    Anaplastic large-cell lymphoma (ALCL) is a rare type of highly malignant, non-Hodgkin lymphoma (NHL). Currently, only studies on the chimeric oncogene NPM-ALK have reported a link to ALCL progression. However, the specific molecular mechanisms underlying the invasion of ALCL are still unclear. Here, we sought to investigate differentially expressed, long non-coding RNAs (lncRNAs) in ALCL and their potential biological function. Our microarray analyses revealed that LINC01013, a novel non-coding RNA gene, was highly expressed in clinical specimens of ALCL and was significantly upregulated in invasive ALCL cell lines. Knockdown of LINC01013 suppressed tumor cell invasion; conversely, its overexpression enhanced tumor cell invasion. LINC01013-induced invasion was mediated by activation of the epithelial-to-mesenchymal transition (EMT)-associated proteins, snail and fibronectin. Specifically, LINC01013 induced snail, resulting in activation of fibronectin and enhanced ALCL cell invasion. Collectively, these findings support a potential role for LINC01013 in cancer cell invasion through the snail-fibronectin activation cascade and suggest that LINC01013 could potentially be utilized as a metastasis marker in ALCL.

  4. Ivermectin efficacy against Biomphalaria, intermediate host snail vectors of Schistosomiasis.

    PubMed

    Katz, Naftale; Araújo, Neusa; Coelho, Paulo Marcos Zech; Morel, Carlos Medicis; Linde-Arias, Ana Rosa; Yamada, Takeshi; Horimatsu, Yuki; Suzuki, Koh; Sunazuka, Toshiaki; Ōmura, Satoshi

    2017-03-15

    The impact of ivermectin on adult snails of the genus Biomphalaria (B. glabrata, B. tenagophila and B. straminea), B. glabrata infected with Schistosoma mansoni, snail egg-masses cercariae and miracidia, as well as on guppy fish (Poecilia reticulata) was examined and evaluated. Biomphalaria snails, egg-masses, parasite stages and guppies were all exposed to different concentrations of ivermectin for 24 h, followed by regular observations of mortality. The calculated lethal doses of ivermectin were around an LD50 of 0.03 μg ml(-1), and an LD90 of 0.3 μg ml(-1) for the three species of snails. Specimens of B. glabrata actually shedding parasite cercariae all died when exposed to ivermectin at a concentration of a mere 0.01 μg ml(-1). Ivermectin B1a, the major (80%) component of commercially available ivermectin, proved to be inactive, and it was the minor (20%) component, ivermectin B1b, which caused snail death. Snail egg-masses were not affected, even at the highest concentration of 100 μg ml(-1). With respect to S. mansoni parasite stages, 0.2 μg ml(-1) ivermectin killed 50% of cercariae and miracidia within five minutes, rising to 90% after 30 min. Mortality of guppy fish within 24 h of exposure to ivermectin at concentrations of 0.5 μg ml(-1) and 0.01 μg ml(-1), were 100% and 30%, respectively. The concentration of 0.01 μg ml(-1) that killed Schistosoma mansoni-infected snails only caused 30% mortality in guppy fish. Ivermectin can be considered a promising molluscicide, especially as it is more potent against infected snails than uninfected ones, although it has no impact on egg-masses. Ivermectin and its derivatives could be explored in the search for a new agent to help control schistosomiasis transmission.The Journal of Antibiotics advance online publication, 15 March 2017; doi:10.1038/ja.2017.31.

  5. Cone snail venomics: from novel biology to novel therapeutics.

    PubMed

    Prashanth, Jutty Rajan; Brust, Andreas; Jin, Ai-Hua; Alewood, Paul F; Dutertre, Sébastien; Lewis, Richard J

    2014-10-01

    Peptide neurotoxins from cone snails called conotoxins are renowned for their therapeutic potential to treat pain and several neurodegenerative diseases. Inefficient assay-guided discovery methods have been replaced by high-throughput bioassays integrated with advanced MS and next-generation sequencing, ushering in the era of 'venomics'. In this review, we focus on the impact of venomics on the understanding of cone snail biology as well as the application of venomics to accelerate the discovery of new conotoxins. We also discuss the continued importance of medicinal chemistry approaches to optimize conotoxins for clinical use, with a descriptive case study of MrIA featured.

  6. One-trial reward learning in the snail Lymnea stagnalis.

    PubMed

    Alexander, J; Audesirk, T E; Audesirk, G J

    1984-01-01

    We present evidence that the pond snail Lymnaea stagnalis is capable of aquisition and extensive retention of an appetitively reinforced feeding response after only a single training trial. Food-deprived snails presented with a single pairing of a phagostimulant (a mixture of sucrose and casein digest) and a novel, non-food chemostimulus (amyl acetate) subsequently made feeding responses to the amyl acetate and retained the association for at least 19 days. This demonstration of one-trial, non-aversive classical conditioning enhances the utility of Lymnaea stagnalis as a model system for the detailed analysis of neural mechanisms underlying plasticity.

  7. Complex impacts of an invasive omnivore and native consumers on stream communities in California and Hawaii.

    PubMed

    Klose, Kristie; Cooper, Scott D

    2013-04-01

    The effects of invasive species on native communities often depend on the characteristics of the recipient community and on the food habits of the invasive species, becoming complicated when the invader is omnivorous. In field enclosure experiments, we assessed the direct and interactive effects of an invasive omnivorous crayfish (Procambarus clarkii) and either native herbivorous snails (Physella gyrina) or shrimp (Atyoida bisulcata) on stream communities in California and Hawaii, respectively. Based on literature data and the characteristics of each study site, we predicted that crayfish would affect primarily algal-based trophic linkages in an open California stream but detritus-based trophic linkages in a shaded Hawaiian stream, with trophic cascades mediated through crayfish effects on primary consumers being observed in both systems. As predicted, crayfish in California directly reduced periphyton, filamentous algae, sediment, and snail levels, but generated a cascade by decreasing snail densities and increasing periphyton biomass. Contrary to prediction, crayfish did not reduce total invertebrate biomass. As predicted, crayfish in Hawaii reduced leaf litter, filamentous algae, and benthic invertebrate biomass. Contrary to our predictions, however, a trophic cascade was not observed because shrimp did not affect periphyton levels, crayfish did not reduce shrimp abundance, and crayfish had greater negative impacts on filamentous algae than did shrimp. Our findings highlight that the same invasive species can generate different effects on disparate systems, probably as mediated through the availability of different food types, flexibility in the invasive species' food habits, and complex pathways of trophic interaction.

  8. Hydrogen peroxide mediates EGF-induced down-regulation of E-cadherin expression via p38 MAPK and snail in human ovarian cancer cells.

    PubMed

    Cheng, Jung-Chien; Klausen, Christian; Leung, Peter C K

    2010-08-01

    In ovarian cancer, it has been shown that E-cadherin is down-regulated by epidermal growth factor (EGF) receptor (EGFR) activation, and that cells with low E-cadherin expression are particularly invasive. Although it is generally believed that reactive oxygen species play important roles in intracellular signal transduction, the role of reactive oxygen species in EGF-mediated reductions in E-cadherin remains to be elucidated. In this study, we show that EGF treatment down-regulated E-cadherin by up-regulating its transcriptional repressors, Snail and Slug, in human ovarian cancer cells. Using 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate acetyl ester staining, we found that intracellular hydrogen peroxide (H(2)O(2)) production was increased in EGF-treated cells and could be inhibited by treatment with an EGFR inhibitor, AG1478, or an H(2)O(2) scavenger, polyethylene glycol (PEG)-catalase. In addition, PEG-catalase diminished EGF-induced p38 MAPK, but not ERK1/2 or c-Jun N-terminal kinase, phosphorylation. PEG-catalase and the p38 MAPK inhibitor SB203580 abolished EGF-induced Snail, but not Slug, expression and E-cadherin down-regulation. Furthermore, the involvement of p38 MAPK in the down-regulation of E-cadherin was confirmed using specific p38alpha MAPK small interfering RNA. Finally, we also show that EGF-induced cell invasion was abolished by treatment with PEG-catalase and SB203580, as well as p38alpha MAPK small interfering RNA, and that forced expression of E-cadherin diminished intrinsic invasiveness as well as EGF-induced cell invasion. This study demonstrates a novel mechanism in which EGF down-regulates E-cadherin expression through production of H(2)O(2), activation of p38 MAPK, and up-regulation of Snail in human ovarian cancer cells.

  9. [The influence of the trematode invasion on the average daily rations and electoral nourishment of Planorbarius corneus (Mollusca: Pulmonata: Bulinidae)].

    PubMed

    Stadnichenko, A P; Girin, V K

    2005-01-01

    The influence of the Trematode invasion on the average daily rations and electoral nourishment of the two size groups in the great ramshorn snail Planorbarius corneus, "young" (12-24 mm in diameter) and "old" (24-36.5 mm in diameter), have been investigated.

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

    PubMed

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

    2010-10-01

    Fish-borne zoonotic trematodes, such as Clonorchis sinensis, heterophyids and others, constitute a public health concern in parts of northern Vietnam and infections with these trematodes are often thought to be linked to fish culture. One common fish culture system is the integrated fish-livestock (VAC) ponds where individual households have 1 or more ponds. Fish fry, mainly of various carp species, produced in hatcheries, not necessarily local, are introduced into nursery ponds and after approximately 6 weeks, juvenile fishes are transferred to household ponds, referred to as grow-out ponds. Grow-out ponds are usually fertilized with organic debris, including animal excreta, to stimulate algal growth and subsequently fish growth. This paper describes the distribution of freshwater snails and occurrence of trematode infections in these in VAC ponds and associated habitats as part of a major study on risk factors of FZT infections in cultured fish in two communes, Nghia Lac and Nghia Phu, Nghia Hung District, Nam Dinh Province. The area is under intense rice cultivation with an extensive canal network supplying fields and also household VAC ponds. A total of 16 snail species was found and four were widely distributed i.e. Angulyagra polyzonata, Melanoides tuberculata, Bithynia fuchsiana and Pomacea insularum. Snail diversity and counts were higher in nursery ponds than in grow-out ponds. Species of the families Thiaridae and Viviparidae were more abundant than other species in VAC ponds while species of the Bithyniidae, Stenothyridae and Planorbidae dominated in rice fields and small canals. Trematode infections were found in eight snail species and among these M. tuberculata had the highest overall prevalence of infection (13.28%). No trematode infections were found in species of the Viviparidae and Ampullaridae except for metacercariae. Parapleurolophocercous and pleurolophocercous cercariae constituted the most common type of cercariae recovered, contributing 40

  11. Nuclear ubiquitination by FBXL5 modulates Snail1 DNA binding and stability

    PubMed Central

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

    2014-01-01

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

  12. Intraguild predation by shore crabs affects mortality, behavior, growth, and densities of California horn snails

    USGS Publications Warehouse

    Lorda, J.; Hechinger, R.F.; Cooper, S. D.; Kuris, A. M.; Lafferty, Kevin D.

    2016-01-01

    The California horn snail, Cerithideopsis californica, and the shore crabs, Pachygrapsus crassipesand Hemigrapsus oregonensis, compete for epibenthic microalgae, but the crabs also eat snails. Such intraguild predation is common in nature, despite models predicting instability. Using a series of manipulations and field surveys, we examined intraguild predation from several angles, including the effects of stage-dependent predation along with direct consumptive and nonconsumptive predator effects on intraguild prey. In the laboratory, we found that crabs fed on macroalgae, snail eggs, and snails, and the size of consumed snails increased with predator crab size. In field experiments, snails grew less in the presence of crabs partially because snails behaved differently and were buried in the sediment (nonconsumptive effects). Consistent with these results, crab and snail abundances were negatively correlated in three field surveys conducted at three different spatial scales in estuaries of California, Baja California, and Baja California Sur: (1) among 61 sites spanning multiple habitat types in three estuaries, (2) among the habitats of 13 estuaries, and (3) among 34 tidal creek sites in one estuary. These results indicate that shore crabs are intraguild predators on California horn snails that affect snail populations via predation and by influencing snail behavior and performance.

  13. A protocol for geographically randomized snail surveys in schistosomiasis fieldwork using the global positioning system.

    PubMed

    Seto, E; Liang, S; Qiu, D; Gu, X; Spear, R C

    2001-01-01

    A protocol was created for performing geographically randomized snail surveys for schistosomiasis research using the global positioning system (GPS). This protocol differs from traditional surveys in its ability to accurately map and measure the spatial distribution of snail habitat. The protocol was used to map irrigation ditches, the primary habitat for Oncomelania hupensis, in two residence areas in Sichuan Province, China. From the 7,450 meters of mapped ditches, snail surveys were performed at 203 random sites along the ditch network. Of these, 116 (57.1%) sites had snails. The total number of living snails captured was 2,014, resulting in an average snail density of 0.27 snails per linear meter of potential habitat.

  14. Effects of serotonin on the heartbeat of pond snails in a hunger state

    PubMed Central

    Yamagishi, Miki; Watanabe, Takayuki; Hatakeyama, Dai; Ito, Etsuro

    2015-01-01

    Serotonin (5-hydroxytryptamine: 5-HT) is a multimodal transmitter that controls both feeding response and heartbeat in snails. However, the effects of 5-HT on the hunger state are still unknown. We therefore examined the relation among the hunger state, the heartbeat rate and the 5-HT action in food-starved snails. We found that the hunger state was significantly distinguished by the heartbeat rate in snails. The heartbeat rate was high in the food-satiated snails, whereas it was low in the food-starved snails. An increase in 5-HT concentration in the body boosted the heartbeat rate in the food-starved snails, but did not affect the rate in the food-satiated snails. These results suggest that 5-HT application may mimic the change from a starvation to a satiation state normally achieved by direct ingestion of food. PMID:27493507

  15. Invasive non-native species' provision of refugia for endangered native species.

    PubMed

    Chiba, Satoshi

    2010-08-01

    The influence of non-native species on native ecosystems is not predicted easily when interspecific interactions are complex. Species removal can result in unexpected and undesired changes to other ecosystem components. I examined whether invasive non-native species may both harm and provide refugia for endangered native species. The invasive non-native plant Casuarina stricta has damaged the native flora and caused decline of the snail fauna on the Ogasawara Islands, Japan. On Anijima in 2006 and 2009, I examined endemic land snails in the genus Ogasawarana. I compared the density of live specimens and frequency of predation scars (from black rats [Rattus rattus]) on empty shells in native vegetation and Casuarina forests. The density of land snails was greater in native vegetation than in Casuarina forests in 2006. Nevertheless, radical declines in the density of land snails occurred in native vegetation since 2006 in association with increasing predation by black rats. In contrast, abundance of Ogasawarana did not decline in the Casuarina forest, where shells with predation scars from rats were rare. As a result, the density of snails was greater in the Casuarina forest than in native vegetation. Removal of Casuarina was associated with an increased proportion of shells with predation scars from rats and a decrease in the density of Ogasawarana. The thick and dense litter of Casuarina appears to provide refugia for native land snails by protecting them from predation by rats; thus, eradication of rats should precede eradication of Casuarina. Adaptive strategies, particularly those that consider the removal order of non-native species, are crucial to minimizing the unintended effects of eradication on native species. In addition, my results suggested that in some cases a given non-native species can be used to mitigate the impacts of other non-native species on native species.

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

    PubMed

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

    2015-01-01

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

  17. Male offspring production by asexual Potamopyrgus antipodarum, a New Zealand snail.

    PubMed

    Neiman, M; Larkin, K; Thompson, A R; Wilton, P

    2012-07-01

    As only females contribute directly to population growth, sexual females investing equally in sons and daughters experience a two-fold cost relative to asexuals producing only daughters. Typically, researchers have focused on benefits of sex that can counter this 'cost of males' and thus explain its predominance. Here, we instead ask whether asexuals might also pay a cost of males by quantifying the rate of son production in 45 experimental populations ('lineages') founded by obligately asexual female Potamopyrgus antipodarum. This New Zealand snail is a powerful model for studying sex because phenotypically similar sexual and asexual forms often coexist, allowing direct comparisons between sexuals and asexuals. After 2 years of culture, 23 of the 45 lineages had produced males, demonstrating that asexual P. antipodarum can make sons. We used maximum-likelihood analysis of a model of male production in which only some lineages can produce males to estimate that ~50% of lineages have the ability to produce males and that ~5% of the offspring of male-producing lineages are male. Lineages producing males in the first year of the experiment were more likely to make males in the second, suggesting that some asexual lineages might pay a cost of males relative to other asexual lineages. Finally, we used a simple deterministic model of population dynamics to evaluate how male production affects the rate of invasion of an asexual lineage into a sexual population, and found that the estimated rate of male production by asexual P. antipodarum is too low to influence invasion dynamics.

  18. Flying shells: historical dispersal of marine snails across Central America

    PubMed Central

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

    2012-01-01

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

  19. A snail-eating snake recognizes prey handedness

    PubMed Central

    Danaisawadi, Patchara; Asami, Takahiro; Ota, Hidetoshi; Sutcharit, Chirasak; Panha, Somsak

    2016-01-01

    Specialized predator-prey interactions can be a driving force for their coevolution. Southeast Asian snail-eating snakes (Pareas) have more teeth on the right mandible and specialize in predation on the clockwise-coiled (dextral) majority in shelled snails by soft-body extraction. Snails have countered the snakes’ dextral-predation by recurrent coil reversal, which generates diverse counterclockwise-coiled (sinistral) prey where Pareas snakes live. However, whether the snake predator in turn evolves any response to prey reversal is unknown. We show that Pareas carinatus living with abundant sinistrals avoids approaching or striking at a sinistral that is more difficult and costly to handle than a dextral. Whenever it strikes, however, the snake succeeds in predation by handling dextral and sinistral prey in reverse. In contrast, P. iwasakii with little access to sinistrals on small peripheral islands attempts and frequently misses capturing a given sinistral. Prey-handedness recognition should be advantageous for right-handed snail-eating snakes where frequently encountering sinistrals. Under dextral-predation by Pareas snakes, adaptive fixation of a prey population for a reversal gene instantaneously generates a sinistral species because interchiral mating is rarely possible. The novel warning, instead of sheltering, effect of sinistrality benefitting both predators and prey could further accelerate single-gene ecological speciation by left-right reversal. PMID:27046345

  20. Arsenic speciation in freshwater snails and its life cycle variation.

    PubMed

    Lai, Vivian W-M; Kanaki, Katerina; Pergantis, Spiros A; Cullen, William R; Reimer, Kenneth J

    2012-03-01

    Terrestrial snails are consumed by humans occasionally and they are an important food source for many creatures including fish and birds. Little is known about arsenic speciation in these gastropods, let alone life cycle variations. Here we report on the arsenic speciation in freshwater snails from Pender Island and Vancouver Island, B.C., Canada, which was determined on methanol/water extracts (43-59% extraction efficiency) by using high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) and HPLC-electrospray tandem mass spectrometry. The tetramethylarsonium ion, oxo-arsenosugars and thio-arsenosugars are the main arsenic species encountered. Arsenobetaine, which is commonly found in the marine environment, is minor. Live bearing snails Viviparidae sp. from Pender Island were maintained in aquaria and the arsenic speciation in the unborn, newly born, and adult animals was monitored. Oxo-arsenosugars predominate in the adults, whereas thio-arsenosugars seem to predominate in juveniles, suggesting that these arsenicals are snail metabolites.

  1. Molecular diversity of avian schistosomes in Danish freshwater snails.

    PubMed

    Christiansen, Anne Ø; Olsen, Annette; Buchmann, Kurt; Kania, Per W; Nejsum, Peter; Vennervald, Birgitte J

    2016-03-01

    Avian schistosomes are widespread parasites of snails and waterfowl and may cause cercarial dermatitis (swimmer's itch) in humans, a disease that is frequently reported in European countries. These parasites are known to occur in Denmark, but here, we applied a new approach using molecular tools to identify the parasites at species level. In order to do that, 499 pulmonate freshwater snails (Radix sp., Lymnaea stagnalis, Stagnicola sp. and Planorbarius corneus) were sampled from 12 lakes, ponds, and marshes in the greater Copenhagen area. Avian schistosome cercariae were identified by microscopy and subjected to molecular investigation by sequencing and phylogenetic analysis of the 5.8S and ITS2 ribosomal DNA for species identification. Additionally, snail hosts belonging to the genus Radix were identified by sequencing and phylogenetic analysis of partial ITS2 ribosomal DNA. Three out of 499 snails shed different species of Trichobilharzia cercariae: Trichobilharzia szidati was isolated from L. stagnalis, Trichobilharzia franki from Radix auricularia and Trichobilharzia regenti from Radix peregra. In the light of the public health risk represented by bird schistosomes, these findings are of concern and, particularly, the presence of the potentially neuro-pathogenic species, T. regenti, in Danish freshwaters calls for attention.

  2. Snail Shells in a Practical Application of Statistical Procedures

    ERIC Educational Resources Information Center

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

    2007-01-01

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

  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. Molluscicidal effect of Eomecon chionantha alkaloids against Oncomelania hupensis snails.

    PubMed

    Peng, Fei; Liu, Ming; Huang, Qiongyao; Liu, Nianmeng; Yang, Huazhong; Sun, Hui; Hu, Qi; Feng, Fang; Jiang, Chonghe

    2011-03-01

    The molluscicidal effects of Eomecon chionantha alkaloids (ECA) against Oncomelania hupensis snails were determined by immersion method. The molluscicidal effect was positively related to ECA concentration, immersion time and temperature of the immersion solution. The mortality of the snails reached 100% by 72 hours in ECA at a concentration of 2.5 mg/l at 25 degrees C. The alanine aminotransferase (ALT) level of liver cells treated with ECA was higher than controls at 24 and 36 hours (57.7 and 60.3 U/l versus 39.2 and 49.2 U/1, respectively) but the level decreased at 48-72 hours after treatment. The decrease points to the toxic effect of ECA against liver cells. After ECA treatment, the liver cells were edematous with swollen or disintegrating nuclei; they were enlarged and had vacuolated rER; they had dilated and vesiculated mitochondria with broken crests further indicating a hepatotoxic effect of ECA in O. hupensis snails. ECA has a molluscicidal effect that may be of practical use in the field to control O. hupensis snails.

  5. 25-Hydroxycholesterol promotes migration and invasion of lung adenocarcinoma cells.

    PubMed

    Chen, Li; Zhang, Lishan; Xian, Guozhe; Lv, Yinping; Lin, Yanliang; Wang, Yibing

    2017-03-18

    25-hydroxycholesterol (25-HC) is enzymatically produced by cholesterol 25-hydorxylase in various organs and is involved in many processes, including lipid metabolism, inflammation and the immune response. However, the role of 25-HC in the migration and invasion of lung adenocarcinoma (ADC) cells remains largely unknown. In this study, we demonstrated that 0.1 μM 25-HC promoted ADC cell migration and invasion without affecting cell proliferation, especially after coculture with THP1-derived macrophages. Further investigation showed that 0.1 μM 25-HC significantly stimulated interleukin-1β (IL-1β) secretion in a coculture system and increased the expression of LXR and Snail. IL-1β also mimicked the effect of 25-HC. LXR knockdown notably blocked the 25-HC-induced Snail expression, migration and invasion in both the monoculture system and the coculture system, but it did not impact the effect of IL-1β, which suggested that IL-1β functioned in an LXR-independent manner. These results suggested that 25-HC promoted ADC cell migration and invasion in an LXR-dependent manner in the monoculture system but that in the coculture system, the 25-HC-induced IL-1β secretion enhanced the effect of 25-HC in an LXR-independent manner.

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

    PubMed

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

    2014-09-01

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

  7. Optimal diet theory: behavior of a starved predatory snail.

    PubMed

    Perry, D M

    1987-06-01

    The tenets of optimal foraging theory are used to contrast the behavior of the predatory snail Acantina spirata when feeding on the barnacles Balanus glandula and Chthamalus fissus under conditions of satiation and starvation. As predicted in optimal diet models, A. spirata is less selective (ratio of attack frequency on a prey species to number of individuals available) when the higher ranking prey has low abundance. When given a choice, starved snails attack both barnacle species equally, whereas satiated individuals preferentially attack B. glandula, the more profitable prey (ash-free dry weight of barnacles ingested per unit handling time). Under starvation conditions, equal attack frequency does not result in equal prey species consumption because Acanthina spirata is more successful at attacking C. fissus than B. glandula.The assumption of constant prey encounter rates in optimal diet models is not met when A. spirata goes from a state of satiation to starvation. The encounter rate on B. glandula is lowered due to a decrease in attack success. A loss of feeding skills in starved A. spirata is responsible for the greater difficulty snails have in gaining access through the opercular plates of B. glandula.Behavioral changes in A. spirata as snails pass from satiation to hunger translate into an energetic disadvantage during feeding for hungry snails for two reasons. First, higher prey handling times result in a decreased rate of biomass intake. Second, alteration in the relative attack frequency between barnacle species, combined with a decrease in attack success on the more profitable prey leads to more frequent ingestion of the less profitable prey.

  8. Invasive Candidiasis.

    PubMed

    McCarty, Todd P; Pappas, Peter G

    2016-03-01

    Invasive candidiasis is a collective term that refers to a group of infectious syndromes caused by a variety of species of Candida, 5 of which cause most cases. Candidemia is the most commonly recognized syndrome associated with invasive candidiasis. Certain conditions may influence the likelihood for one species versus another in a specific clinical scenario, and this can have important implications for selection of antifungal therapy and the duration of treatment. Molecular diagnostic technology plays an ever-increasing role as an adjunct to traditional culture-based diagnostics, offering significant potential toward improvement in patient care.

  9. Did life history evolve in response to parasites in invasive populations of Melanoides tuberculata?

    NASA Astrophysics Data System (ADS)

    Escobar, Juan Sebastián; Correa, Ana Cristina; David, Patrice

    2009-09-01

    Enemy release and rapid evolution are often assumed to promote biological invasions. In the parthenogenetic snail Melanoides tuberculata, one invasive strain (MAD) was assumed to benefit from enemy release until a heavily parasitized population was found in Colombia (in the area of introduction). This population is prosperous despite important losses in the reproductive potential due to a high prevalence of a trematode that castrates snails. We studied genetic variation in life-history traits among five populations from the invaded area to test whether life histories had recently evolved in the parasitized population in such a way that snails have more chance to reproduce before being parasitized. We find significant genetic differences among populations, though they are not in the expected direction. Individuals from the parasitized population were smaller at birth, grew slower, and reproduced later and at a bigger size than individuals from the non-parasitized populations. We conclude that the life-history traits of this snail strain did not need to evolve in order to allow population renewal in the invaded area, even in the presence of parasites. This implies that enemy release and/or rapid evolution were not necessary for this strain to invade.

  10. Lymnaea glabra: progressive increase in susceptibility to Fasciola hepatica through successive generations of experimentally infected snails.

    PubMed

    Rondelaud, D; Teukeng, F F Djuikwo; Vignoles, P; Dreyfuss, G

    2015-07-01

    Experimental infections of Lymnaea glabra (two populations) with Fasciola hepatica were carried out during seven successive snail generations, to determine if prevalence and intensity of snail infection increased over time through descendants of snails already infected with F. hepatica. Controls were descendants coming from uninfected parents and infected according to the same protocol. No larval forms were found in the bodies of control snails coming from uninfected parents. In contrast, prevalence and intensity of F. hepatica infection in snails originating from infected parents progressively increased from the F2 or F3 to the F6 generation of L. glabra. In another experiment carried out with the F7 generations of L. glabra and a single generation of Galba truncatula (as controls), the prevalence of F. hepatica infection and the total number of cercariae were lower in L. glabra (without significant differences between both populations). If the number of cercariae shed by infected snails was compared to overall cercarial production noted in snails containing cercariae but dying without emission, the percentage was greater in G. truncatula (69% instead of 52-54% in L. glabra). Even if most characteristics of F. hepatica infection were lower in L. glabra, prevalence and intensity of parasite infection increased with snail generation when tested snails came from infected parents. This mode of snail infection with F. hepatica suggests an explanation for cases of fasciolosis occurring in cattle-breeding farms where paramphistomosis is lacking and G. truncatula is absent.

  11. Snail as a key regulator of PRL-3 gene in colorectal cancer.

    PubMed

    Zheng, Ping; Meng, Hui-Min; Gao, Wei-Zhe; Chen, Lin; Liu, Xun-Hua; Xiao, Zheng-Quan; Liu, Yong-Xia; Sui, Hong-Mei; Zhou, Jun; Liu, Yu-Hong; Li, Jian-Ming

    2011-10-15

    The regulators of a key metastasis gene PRL-3 in colorectal cancer (CRC) are still largely unknown. We found three potential binding sites of Snail, a key transcriptional factor involved in the epithelial-mesenchymal transition (EMT), in the region of PRL-3 promoter (located at -642 to -383). Moreover, our results showed that one of the Snail binding sites (located at -624 to -619) was the key element to maintain promoter activity of human PRL-3 gene. The transcriptional activity of PRL-3 promoter was abolished after the Snail binding site (located at -624 to -619) was mutated. Both promoter activity and protein expression of PRL-3 in CRC cell lines could be regulated by Snail. In clinical samples of CRC and metastatic lymph node of CRC, expression of PRL-3 protein was correlated with expression of Snail protein. Functional studies using gene over-expression and knockdown methods indicated that Snail promoted proliferation, cell adhesion and migration of human CRC cells. In SW480 cells with PRL-3 stable knockdown, cell proliferation increased after Snail was up-regulated. Our data first reveal transcriptional factor Snail as a key regulator of PRL-3 in CRC. The link between Snail and PRL-3 suggests a new potential mechanism of Snail contributing to progression and metastasis of CRC.

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

    PubMed

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

    2011-11-01

    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. 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.

  14. Reversing the resistance phenotype of the Biomphalaria glabrata snail host Schistosoma mansoni infection by temperature modulation.

    PubMed

    Ittiprasert, Wannaporn; Knight, Matty

    2012-01-01

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

  15. 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 β1 (TGF-β1) 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.

  16. Osthole inhibited TGF β-induced epithelial-mesenchymal transition (EMT) by suppressing NF-κB mediated Snail activation in lung cancer A549 cells.

    PubMed

    Feng, Haitao; Lu, Jin-Jian; Wang, Yitao; Pei, Lixia; Chen, Xiuping

    2017-02-01

    Epithelial-mesenchymal transition (EMT), the transdifferentiation of epithelial cells into mesenchymal cells, has been implicated in the metastasis and provides novel strategies for cancer therapy. Osthole (OST), a dominant active constituent of Chinese herb Cnidium monnieri, has been reported to inhibit cancer metastasis while the mechanisms remains unclear. Here, we studied the inhibitory effect and mechanisms of OST on TGF-β1-induced EMT in A549 cells. Cells were treated with TGF-β1 in the absence and presence of OST. The morphological alterations were observed with a microscopy. The protein and mRNA expressions were determined by Western blotting and real-time PCR. The protein localization was detected with immunofluorescence. The adhesion, migration, and invasion were determined by Matrigel, wound-healing, and Transwell assays. TGF-β1 treatment induced spindle-shaped alterations of cells, upregulation of N-cadherin, Vimentin, NF-κB p65, and downregulation of E-cadherin. Dysregulated membrane expression and mRNA expression of E-cadherin and N-cadherin were observed after TGF-β1 treatment. TGF-β1 increased abilities of migration and invasion and triggered the nuclear translocation of NF-κB p65. These alterations were dramatically inhibited by OST. Furthermore, PDTC, a NF-κB inhibitor, showed similar effects. In addition, TGF-β1-induced expression of Snail was significantly inhibited by OST and silenced Snail partially reversed TGF-β1-induced EMT biomarkers without affecting NF-κB p-65. In conclusion, OST inhibited TGF-β1-induced EMT, adhesion, migration, and invasion through inactivation of NF-κB-Snail pathways in A549 cells. This study provides novel molecular mechanisms for the anti-metastatic effect of OST.

  17. Novel Animal Defenses against Predation: A Snail Egg Neurotoxin Combining Lectin and Pore-Forming Chains That Resembles Plant Defense and Bacteria Attack Toxins

    PubMed Central

    Ceolín, Marcelo; Ituarte, Santiago; Qiu, Jian-Wen; Sun, Jin; Fernández, Patricia E.; Heras, Horacio

    2013-01-01

    Although most eggs are intensely predated, the aerial egg clutches from the aquatic snail Pomacea canaliculata have only one reported predator due to unparalleled biochemical defenses. These include two storage-proteins: ovorubin that provides a conspicuous (presumably warning) coloration and has antinutritive and antidigestive properties, and PcPV2 a neurotoxin with lethal effect on rodents. We sequenced PcPV2 and studied whether it was able to withstand the gastrointestinal environment and reach circulation of a potential predator. Capacity to resist digestion was assayed using small-angle X-ray scattering (SAXS), fluorescence spectroscopy and simulated gastrointestinal proteolysis. PcPV2 oligomer is antinutritive, withstanding proteinase digestion and displaying structural stability between pH 4.0–10.0. cDNA sequencing and protein domain search showed that its two subunits share homology with membrane attack complex/perforin (MACPF)-like toxins and tachylectin-like lectins, a previously unknown structure that resembles plant Type-2 ribosome-inactivating proteins and bacterial botulinum toxins. The protomer has therefore a novel AB toxin combination of a MACPF-like chain linked by disulfide bonds to a lectin-like chain, indicating a delivery system for the former. This was further supported by observing PcPV2 binding to glycocalix of enterocytes in vivo and in culture, and by its hemaggutinating, but not hemolytic activity, which suggested an interaction with surface oligosaccharides. PcPV2 is able to get into predator’s body as evidenced in rats and mice by the presence of circulating antibodies in response to sublethal oral doses. To our knowledge, a lectin-pore-forming toxin has not been reported before, providing the first evidence of a neurotoxic lectin in animals, and a novel function for ancient and widely distributed proteins. The acquisition of this unique neurotoxic/antinutritive/storage protein may confer the eggs a survival advantage, opening new

  18. 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

  19. Irisin suppresses the migration, proliferation, and invasion of lung cancer cells via inhibition of epithelial-to-mesenchymal transition.

    PubMed

    Shao, Lei; Li, Huanjie; Chen, Jian; Song, Haibo; Zhang, Yuzhu; Wu, Fei; Wang, Wenjuan; Zhang, Wen; Wang, Fang; Li, Hui; Tang, Dongqi

    2017-04-08

    Irisin is involved in promoting metabolism, immune regulation, and affects chronic inflammation in many systemic diseases, including gastric cancer. However, the role of irisin in lung cancer is not well characterized. To determine whether irisin has a protective effect against lung cancer, we cultured A549 and NCI-H446 lung cancer cells and treated them with irisin. We detected the proliferation by MTT assay, and assessed the migration and invasion of the cells by scratch wound healing assay and Tran-swell assay. The expression levels of epithelial-to-mesenchymal transition (EMT) markers and the related signaling pathways were detected by western blot analysis. Meanwhile, an inhibitor of PI3K was used to investigate the effect of irsin. Finally, the expression of Snail was detected. We demonstrated that irisin inhibits the proliferation, migration, and invasion of lung cancer cells, and has a novel role in mediating the PI3K/AKT pathway in the cells. Irisin can reverse the activity of EMT and inhibit the expression of Snail via mediating the PI3K/AKT pathway, which is a key regulator of Snail. These results revealed that irisin inhibited EMT and reduced the invasion of lung cancer cells via the PI3K/AKT/Snail pathway.

  20. Metabolic acceleration in the pond snail Lymnaea stagnalis?

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  1. Snail/Slug-YAP/TAZ Complexes Control Skeletal Stem Cell Self-Renewal and Differentiation

    PubMed Central

    Tang, Yi; Feinberg, Tamar; Keller, Evan T.; Li, Xiao-Yan; Weiss, Stephen J.

    2016-01-01

    Bone marrow-derived skeletal stem/stromal cell (SSC) self-renewal and function are critical to skeletal development, homeostasis and repair. Nevertheless, the mechanisms controlling SSC behavior, particularly bone formation, remain ill-defined. Using knockout mouse models that target the zinc-finger transcription factors, Snail, Slug or Snail and Slug combined, a regulatory axis has been uncovered wherein Snail and Slug cooperatively control SSC self-renewal, osteoblastogenesis and bone formation. Mechanistically, Snail/Slug regulate SSC function by forming complexes with the transcriptional co-activators, YAP and TAZ, in tandem with the inhibition of the Hippo pathway-dependent regulation of YAP/TAZ signaling cascades. In turn, the Snail/Slug-YAP/TAZ axis activates a series of YAP/TAZ/TEAD and Runx2 downstream targets that control SSC homeostasis and osteogenesis. Together, these results demonstrate that SSCs mobilize Snail/Slug-YAP/TAZ complexes to control stem cell function. PMID:27479603

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

    PubMed

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

    2010-01-01

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

  3. First report of Toxocara cati in the domestic land snail Rumina decollata.

    PubMed

    Cardillo, Natalia; Prous, Cintia Gonzalez; Krivokapich, Silvio; Pittaro, Mariana; Ercole, Mariano; Perez, Matías; Pasqualetti, Mariana; Fariña, Fernando; Rosa, Adriana; Gatti, Graciana; Ribicich, Mabel

    The prospective role of the land snail Rumina decollata as a potential paratenic host of Toxocara cati for domestic cats was studied. R. decollata specimens and cats' feces were collected from the open spaces of a Buenos Aires city hospital. Cats' feces were analyzed and snails were digested to identify T. cati stages, by morphological and molecular analyses. T. cati larval eggs were recovered from 23.5% (4/17) of the sampled feces. Twenty percent of snail pools (5/25) were confirmed to be positive for Toxocara spp. third larval stage (L3) by PCR. The mean value of total larvae recovered per gram of snail in all positive pools was 5.1, with a maximum 33 L3/pool. This is the first report of T. cati infective larvae in R. decollata domestic snail as a paratenic host, since the relationship between infection in snails and in cats' feces could be demonstrated in a common environment.

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

    PubMed Central

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

    2010-01-01

    The effects of snail density on Biomphalaria alexandrina parasitized with Schistosoma mansoni were investigated. Laboratory experiments were used to quantify the impact of high density on snail growth, fecundity, and survival. Density-dependent birth rates of snails were determined to inform mathematical models, which, until now, have assumed a linear relationship between density and fecundity. The experiments show that the rate of egg-laying followed a negative exponential distribution with increasing density and this was significantly affected by exposure to parasitic infection. High density also affected the weight of snails and survival to a greater degree than exposure to parasitic infection. Although snail growth rates were initially constrained by high density, they retained the potential for growth suggesting a reversible density-dependent mechanism. These experimental data can be used to parameterise models and confirm that snail populations are regulated by nonlinear density-dependent mechanisms. PMID:20700427

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

    NASA Astrophysics Data System (ADS)

    Al-Daihan, Sooad

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

  6. BHC80 is Critical in Suppression of Snail-LSD1 Interaction and Breast Cancer Metastasis

    DTIC Science & Technology

    2013-01-01

    inhibitors combined with the DNA alkylating agent Temozolomide are under investigation in several clinical trials. Due to the variance in cell...indicating that PARP1 becomes activated in response to DNA -damaging agent and promotes the interaction of Snail/LSD1 with PTEN promoter. Also as expected...by inhibiting PARG could enhance Snail-LSD1 interaction . In addition, we found that Snail could undergo poly(ADP-ribosyl)ation on DNA damage

  7. Co-expression and clinical utility of Snail and N-cadherin in papillary thyroid carcinoma.

    PubMed

    Yang, Xiangshan; Shi, Ranran; Zhang, Jing

    2016-01-01

    Papillary thyroid carcinoma is one of the most common subtypes of thyroid cancer and portends a good prognosis. N-cadherin (neural cadherin) is a member of the classical cadherin family and is often overexpressed in many types of cancers. Snail, a kind of zinc finger protein, is a transcriptional repressor which has been intensively studied in mammals. We investigate the immunohistochemical expression of Snail and N-cadherin in papillary thyroid carcinoma tissues and cells and then discuss the clinical value of Snail and N-cadherin expression. Immunohistochemical technique was performed to detect Snail and N-cadherin in 60 cases of papillary thyroid carcinoma and analyzed the relationship between the expression of Snail, N-cadherin, and clinicopathological indicators. Western blot was used to investigate the constitutive and inducible expression of Snail and N-cadherin. In our study, the expression rate of Snail and N-cadherin was 85.0 % (51/60) and 78.3 % (47/60), respectively, in papillary thyroid carcinoma. The expression rate of Snail and N-cadherin in thyroid papillary carcinoma with metastatic lymph nodes was 93.3 and 86.7 %, respectively, while in papillary thyroid carcinoma tissue without lymph node metastasis, the expression rate was 60.0 and 53.3 %, respectively. The positive correlation of Snail and N-cadherin was observed (r = 0.721, p < 0.01). In addition, Western blot further identified the constitutive and inducible expression of Snail and N-cadherin in papillary thyroid carcinoma tissues and cell lines. In conclusion, Snail and N-cadherin are constitutively and inducibly expressed in papillary thyroid carcinoma and may play important roles in the development and metastasis of papillary thyroid carcinoma. Snail and N-cadherin may be used as an effective indicator.

  8. 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

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

    USGS Publications Warehouse

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

    1987-01-01

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

  10. BHC80 is Critical in Suppression of Snail-LSD1 Interaction and Breast Cancer Metastasis

    DTIC Science & Technology

    2014-04-01

    1-0078 TITLE: BHC80 is Critical in Suppression of Snail -LSD1 Interaction and Breast Cancer Metastasis PRINCIPAL INVESTIGATOR: Yiwei...COVERED (From - To) 1 Jan 2011 - 31 Dec 2013 4. TITLE AND SUBTITLE BHC80 is critical in suppression of Snail -LSD1 interaction and 5a...distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT By using a tandem affinity-mass spectrometry coupled analysis, we identified Snail

  11. Storage excretion in the Indian apple snail, Pila globosa (Swainson), during aestivation.

    PubMed

    Athawale, Madhura S; Reddy, S Raghupathi Rami

    2002-11-01

    Uric acid accumulates in several tissues of the Indian apple snail, P. globosa, during aestivation. This accumulation is particularly high in the foot muscle and reproductive organs. Since the kidney, a tiny organ in the snail, has only a limited capacity to store uric acid, extrarenal tissues are used as storage depots of uric acid during aestivation. It is suggested that the aestivating snail, faced with a cleidoic situation, resorts to storage excretion, a phenomenon well documented in insects.

  12. 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

  13. Multiple paternity in the freshwater snail, Potamopyrgus antipodarum.

    PubMed

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

    2012-12-01

    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.

  14. Structure of mega-hemocyanin reveals protein origami in snails.

    PubMed

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

    2015-01-06

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

  15. Factors determining the direction of ecological specialization in snail-feeding carabid beetles.

    PubMed

    Konuma, Junji; Nagata, Nobuaki; Sota, Teiji

    2011-02-01

    A stout-slender dimorphism in body shape is observed among carabid beetles of the subtribe Carabina, which feed on land snails. We hypothesized that this dimorphism has resulted from divergent ecological specialization for feeding on different-sized land snails. Therefore, we examined whether the geographic variation in the body shape of Damaster blaptoides, a representative snail-feeding species in Japan, is correlated with the size of Euhadra, a genus of land snails frequently consumed by D. blaptoides. An analysis of beetle specimens from the whole distribution area of D. blaptoides determined that more slender beetle populations occurred in localities harboring larger snails, whereas more stout beetles inhabited localities harboring smaller snails. This pattern could be adaptive because slender beetles exhibit high feeding performance for large snails by inserting their heads into the shells, whereas stout beetles do so for small snails by crushing the shells. The D. blaptoides populations showed a clear genetic isolation-by-distance pattern, which could be effective in promoting such local adaptation. Thus, food resources as well as geographic isolation may have promoted adaptive divergence of external morphology in the snail-feeding carabid beetles.

  16. Snail1 is required for the maintenance of the pancreatic acinar phenotype

    PubMed Central

    Loubat-Casanovas, Jordina; Peña, Raúl; Gonzàlez, Núria; Alba-Castellón, Lorena; Rosell, Santi; Francí, Clara; Navarro, Pilar; de Herreros, Antonio García

    2016-01-01

    The Snail1 transcriptional factor is required for correct embryonic development, yet its expression in adult animals is very limited and its functional roles are not evident. We have now conditionally inactivated Snail1 in adult mice and analyzed the phenotype of these animals. Snail1 ablation rapidly altered pancreas structure: one month after Snail1 depletion, acinar cells were markedly depleted, and pancreas accumulated adipose tissue. Snail1 expression was not detected in the epithelium but was in pancreatic mesenchymal cells (PMCs). Snail1 ablation in cultured PMCs downregulated the expression of several β-catenin/Tcf-4 target genes, modified the secretome of these cells and decreased their ability to maintain acinar markers in cultured pancreas cells. Finally, Snail1 deficiency modified the phenotype of pancreatic tumors generated in transgenic mice expressing c-myc under the control of the elastase promoter. Specifically, Snail1 depletion did not significantly alter the size of the tumors but accelerated acinar-ductal metaplasia. These results demonstrate that Snail1 is expressed in PMCs and plays a pivotal role in maintaining acinar cells within the pancreas in normal and pathological conditions. PMID:26735179

  17. Differential expression of transcriptional repressor snail gene at implantation site in mouse uterus.

    PubMed

    Ma, Xing-Hong; Hu, Shi-Jun; Yu, Hao; Xu, Li-Bin; Yang, Zeng-Ming

    2006-02-01

    The snail superfamily of zinc-finger transcription factors is involved in pronounced cell movements during both embryonic development and tumor progression. This study was to examine snail expression in mouse uterus during early pregnancy and its regulation under pseudopregnancy, delayed implantation, steroid hormone treatment, and artificial decidualization by in situ hybridization and immunohistochemistry. There was a low level of snail mRNA signal and immunostaining in mouse uteri on day 1-4 of pregnancy. When embryo implanted on day 5, both snail mRNA signal and immunostaining were strongly detected in the subluminal stroma immediately surrounding the implanting blastocyst, but not detected in the inter-implantation sites. Under delayed implantation, there was no detectable snail expression. After delayed implantation was terminated by estrogen treatment and embryo implanted, there was a strong level of snail mRNA and immunostaining in the subluminal stroma surrounding the implanting blastocyst, which was similar to that on day 5 of pregnancy. Furthermore, there was no detectable snail expression in mouse uterus on day 5 of pseudopregnancy. From day 6-8 of pregnancy, both snail mRNA signal and immunostaining were detected in the decidua. Our data suggest that snail may play an important role during mouse embryo implantation.

  18. Action of SNAIL1 in Cardiac Myofibroblasts Is Important for Cardiac Fibrosis following Hypoxic Injury

    PubMed Central

    Biswas, Hirak; Longmore, Gregory D.

    2016-01-01

    Hypoxic injury to the heart results in cardiac fibrosis that leads to cardiac dysfunction and heart failure. SNAIL1 is a zinc finger transcription factor implicated in fibrosis following organ injury and cancer. To determine if the action of SNAIL1 contributed to cardiac fibrosis following hypoxic injury, we used an endogenous SNAIL1 bioluminescence reporter mice, and SNAIL1 knockout mouse models. Here we report that SNAIL1 expression is upregulated in the infarcted heart, especially in the myofibroblasts. Utilizing primary cardiac fibroblasts in ex vivo cultures we find that pro-fibrotic factors and collagen I increase SNAIL1 protein level. SNAIL1 is required in cardiac fibroblasts for the adoption of myofibroblast fate, collagen I expression and expression of fibrosis-related genes. Taken together this data suggests that SNAIL1 expression is induced in the cardiac fibroblasts after hypoxic injury and contributes to myofibroblast phenotype and a fibrotic scar formation. Resultant collagen deposition in the scar can maintain elevated SNAIL1 expression in the myofibroblasts and help propagate fibrosis. PMID:27706205

  19. Fasciola hepatica in snails collected from water-dropwort fields using PCR.

    PubMed

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

    2014-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Hodgson, Alan N.; Dickens, John

    2012-08-01

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

  1. Piscivorous behavior of a temperate cone snail, Conus californicus.

    PubMed

    Stewart, Julia; Gilly, William F

    2005-10-01

    Most of the more than 500 species of predatory marine snails in the genus Conus are tropical or semitropical, and nearly all are thought to be highly selective regarding type of prey. Conus californicus Hinds, 1844, is unusual in that it is endemic to the North American Pacific coast and preys on a large variety of benthic organisms, primarily worms and other molluscs, and also scavenges. We studied the feeding behavior of C. californicus in captivity and found that it regularly killed and consumed live prickleback fishes (Cebidichthys violaceus and Xiphister spp.). Predation involved two behavioral methods similar to those employed by strictly piscivorous relatives. One method utilized stings delivered by radular teeth; the other involved engulfing the prey without stinging. Both methods were commonly used in combination, and individual snails sometimes employed multiple stings to subdue a fish. During the course of the study, snails became aroused by the presence of live fish more quickly, as evidenced by more rapid initiation of hunting behavior. Despite this apparent adaptation, details of prey-capture techniques and effectiveness of stings remained similar over the same period.

  2. Impact of cigarette butt leachate on tidepool snails.

    PubMed

    Booth, David J; Gribben, Paul; Parkinson, Kerryn

    2015-06-15

    In urban areas, cigarette butts are the most common discarded refuse articles. In marine intertidal zones, they often fall into tidepools. We tested how common intertidal molluscs were affected by butt leachate in a laboratory experiment, where snails were exposed to various leachate concentrations. Mortality was very high, with all species showing 100% mortality at the full leachate concentration (5 butts per litre and 2h soak time) after 8days. However, Austrocochlea porcata showed higher mortality than the other 2 species at lower concentrations (10%, 25%) which may affect the relative abundance of the 3 snails under different concentrations of leachate pollution. Also, sublethal effects of leachate on snail activity were observed, with greater activity of Nerita atramentosa than the other 2 species at higher concentrations, suggesting it is more resilient than the other 2 species. While human health concerns predominate with respect to smoking, we show strong lethal and sublethal (via behavioural modifications) impacts of discarded butts on intertidal organisms, with even closely-related taxa responding differently.

  3. Predicting the Potential for Invasive Species Establishment by Using Environmental Tolerance Data

    DTIC Science & Technology

    2010-05-01

    ERDC/TN ANSRP-10-2 May 2010 1 Predicting the Potential for Invasive Species Establishment by Using Environmental Tolerance Data by Judy F...world where common carp have established , thus increasing the likelihood that the species would become estab- lished and widespread throughout the...Carp), Limnoperna fortunei (Asian mussel) and Potamopyrgus antipodarum (New Zealand mud snail) (Chen et al. 2007; Loo et al. 2007). A GARP model was

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

    PubMed

    Rashed, A A

    2002-12-01

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

  5. 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

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

    2015-08-01

    Of the approximately 34 identified Biomphalariaspecies,Biomphalaria alexandrinarepresents the intermediate host of Schistosoma mansoniin Egypt. Using parasitological and SOD1 enzyme assay, this study aimed to elucidate the impact of the age of B. alexandrinasnails on their genetic variability and internal defence against S. mansoniinfection. 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 Biomphalariacontrol. 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.

  6. A trematode parasite alters growth, feeding behavior, and demographic success of invasive rusty crayfish (Orconectes rusticus).

    PubMed

    Sargent, Lindsey W; Baldridge, Ashley K; Vega-Ross, Maraliz; Towle, Kevin M; Lodge, David M

    2014-07-01

    Nonindigenous species can cause major changes to community interactions and ecosystem processes. The strong impacts of these species are often attributed to their high demographic success. While the importance of enemy release in facilitating invasions has often been emphasized, few studies have addressed the role of parasites in the invasive range in controlling demographic success of potential invaders. Here we examine whether a trematode parasite (Microphallus spp.) can contribute to previously documented alternate states in the abundance of invasive rusty crayfish (Orconectes rusticus) in north temperate lakes in Wisconsin, USA. Microphallus infect O. rusticus after emerging from their first intermediate host, a hydrobiid snail. As previously documented, O. rusticus reduce densities of hydrobiid snails through direct predation and destruction of macrophyte habitat. Therefore, if Microphallus substantially reduce O. rusticus fitness, these parasites may reinforce a state of low crayfish abundance, and, at the other extreme, abundant crayfish may repress these parasites, reinforcing a state of high crayfish abundance. From samples collected from 109 sites in 16 lakes, we discovered (1) a positive relationship between crayfish infection intensity and hydrobiid snail abundance, (2) a negative relationship between parasite prevalence and crayfish abundance, and (3) a negative relationship between parasite prevalence and crayfish population growth. With experiments, we found that infection with Microphallus reduced foraging behavior and growth in O. rusticus, which may be the mechanisms responsible for the population reductions we observed. Overall results are consistent with the hypothesis that Microphallus contributes to alternate states in the abundance and impacts of O. rusticus.

  7. 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...

  8. 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

  9. Residential yards as designer ecosystems: effects of yard management on land snail species composition.

    PubMed

    Bergey, Elizabeth A; Figueroa, Laura L

    2016-12-01

    Residential yards comprise the majority of green space in urban landscapes, yet are an understudied system because of access issues and because yards may be considered biologically depauperate. Yards are purposely created and managed and, hence, qualify as designer ecosystems, a term borrowed from restoration ecology. We investigated whether yard management (watering regime, mulching, and chemical use) or dog presence affected land snail assemblage composition and described the pattern of native vs. nonnative species among yards. Land snails form an appropriate model system for yard-scale studies because snails are speciose, common, and have limited mobility. We found 32 land snail species in our survey of 61 yards in Norman, Oklahoma, USA (population size of 118,000). Snail richness in individual yards averaged nine species, with a range of three to 14 species. Native snails were found in all yards and nonnative snails were found in all but one yard. Although some of the nine nonnative species were rare, the most frequently encountered species was the nonnative Triodopsis hopetonensis. All encountered nonnative species also occur in Oklahoma plant nurseries, indicating possible introduction through the plant trade. Yard-scale watering regime and the presence of dogs were associated with differences in snail species composition but not species richness. Pesticide use and mulch type had little, if any, association with snail composition. Effects may have been diluted by treating yards as units, whereas snails were concentrated in specific microhabitats, such as under shrubs. Soil type also influenced snail assemblages and acted at a scale larger than individual yards. Considering yards as designer ecosystems facilitates investigation of how local variation in management affects biota within yards and across the residential landscape, and highlights the importance of variation among residential yards in understanding patterns of urban biodiversity.

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

    PubMed

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

    2013-03-01

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

  11. Mortality estimate of Chinese mystery snail, Bellamya chinensis (Reeve, 1863) in a Nebraska reservoir

    USGS Publications Warehouse

    Haak, Danielle M.; Chaine, Noelle M.; Stephen, Bruce J.; Wong, Alec; Allen, Craig R.

    2013-01-01

    The Chinese mystery snail (Bellamya chinensis) is an aquatic invasive species found throughout the USA. Little is known about this species’ life history or ecology, and only one population estimate has been published, for Wild Plum Lake in southeast Nebraska. A recent die-off event occurred at this same reservoir and we present a mortality estimate for this B. chinensis population using a quadrat approach. Assuming uniform distribution throughout the newly-exposed lake bed (20,900 m2), we estimate 42,845 individuals died during this event, amounting to approximately 17% of the previously-estimated population size of 253,570. Assuming uniform distribution throughout all previously-reported available habitat (48,525 m2), we estimate 99,476 individuals died, comprising 39% of the previously-reported adult population. The die-off occurred during an extreme drought event, which was coincident with abnormally hot weather. However, the exact reason of the die-off is still unclear. More monitoring of the population dynamics of B. chinensis is necessary to further our understanding of this species’ ecology.

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

    PubMed

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

    2014-12-01

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

  13. Special AT-rich sequence-binding protein-1 participates in the maintenance of breast cancer stem cells through regulation of the Notch signaling pathway and expression of Snail1 and Twist1.

    PubMed

    Sun, Zhengkui; Zhang, Chao; Zou, Xuesen; Jiang, Guixiang; Xu, Zongquan; Li, Wenting; Xie, Hui

    2015-05-01

    The stem cell populations in cancerous tissues and cell lines vary widely and are often associated with aggressive cases of breast cancer. Despite research on the topic, the mechanism underlying the regulation of the breast cancer stem cell (BCSC) population within tumors remains to be fully elucidated. To investigate the function of special AT‑rich sequence‑binding protein‑1 (SATB1) in the maintenance of the BCSC population, SATB1 was overexpressed with lentivirus in MCF‑7 cells or knocked down with shRNA‑lentivirus in BT‑549 cells. The effects of SATB1 overexpression or knockdown on mammosphere formation, the size of the of BCSC population, cell invasion and tumorigenesis were investigated. Activation of the Notch signaling pathway and expression of Snail1 and Twist1 were also examined in the cells. Overexpression of SATB1 in MCF‑7 cells was observed to increase mammosphere formation, the size of the BCSC population, cell invasion and tumorigenesis, accompanied by an increase in the activation of Notch signaling and expression levels of Snail1 and Twist1. Conversely, knockdown of SATB1 in BT‑549 cells produced the opposite effects. The results indicated that expression of SATB1 may increase the size of the BCSC population via the activation of the Notch signaling pathway and by increasing expression levels of Snail1 and Twist1.

  14. Long non-coding RNA CCAT2 is associated with poor prognosis in hepatocellular carcinoma and promotes tumor metastasis by regulating Snail2-mediated epithelial–mesenchymal transition

    PubMed Central

    Xu, Yongfu; Wang, Binfeng; Zhang, Fabiao; Wang, Aidong; Du, Xuefeng; Hu, Peng; Zhu, Yu; Fang, Zheping

    2017-01-01

    Increasing evidence has demonstrated that aberrant expressions of long non-coding RNAs (lncRNAs) are involved in various malignancies, including hepatocellular carcinoma (HCC). This study aimed to investigate the role of lncRNA colon cancer-associated transcript 2 (CCAT2) in the progression of HCC. Quantitative real-time polymerase chain reaction analysis confirmed that CCAT2 was upregulated in HCC cell lines and cancerous tissues compared with normal liver cell line and adjacent normal tissue samples. The level of CCAT2 was positively associated with tumor–node–metastasis stages and vessel invasion. Survival analyses revealed that high CCAT2 expression predicted poor prognostic outcomes, serving as an independent prognostic factor for HCC patients. Patients with high CCAT2 expression had a 1.849-fold increased risk of death compared with those with low CCAT2 expression. Moreover, we also found that knockdown of CCAT2 expression reduced cell migration and invasion in vitro. We further demonstrated that CCAT2 played a key role in enhancing the epithelial–mesenchymal transition (EMT) through the regulation of vimentin, E-cadherin and transcription factor snail2 expression. Taken together, our findings showed that high CCAT2 expression is associated with poor survival in HCC patients. CCAT2 promotes HCC progression by regulating Snail2-induced EMT. CCAT2 may be a prognostic biomarker and therapeutic target for HCC. PMID:28280353

  15. Effects of pollution on land snail abundance, size and diversity as resources for pied flycatcher, Ficedula hypoleuca.

    PubMed

    Eeva, Tapio; Rainio, Kalle; Suominen, Otso

    2010-09-01

    Passerine birds need extra calcium during their breeding for developing egg shells and proper growth of nestling skeleton. Land snails are an important calcium source for many passerines and human-induced changes in snail populations may pose a severe problem for breeding birds. We studied from the bird's viewpoint how air pollution affects the shell mass, abundance and diversity of land snail communities along a pollution gradient of a copper smelter. We sampled remnant snail shells from the nests of an insectivorous passerine, the pied flycatcher, Ficedula hypoleuca, to find out how the availability of land snails varies along the pollution gradient. The total snail shell mass increased towards the pollution source but declined abruptly in the vicinity of the smelter. This spatial variation in shell mass was evident also within a single snail species and could not be wholly explained by spatially varying snail numbers or species composition. Instead, the total shell mass was related to their shell size, individuals being largest at the moderately polluted areas. Smaller shell size suggests inferior growth of snails in the most heavily polluted area. Our study shows that pollution affects the diversity, abundance (available shell mass) and individual quality of land snails, posing reproductive problems for birds that rely on snails as calcium sources during breeding. There are probably both direct pollution-related (heavy metal and calcium levels) and indirect (habitat change) effects behind the observed changes in snail populations.

  16. 77 FR 54605 - Longworth Low-Effect Habitat Conservation Plan for the Morro Shoulderband Snail, Community of Los...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-05

    ... for the Morro Shoulderband Snail, Community of Los Osos, San Luis Obispo County, CA AGENCY: Fish and... addresses the potential for ``take'' of the federally endangered Morro shoulderband snail that is likely to... project activities that are likely to result in take of the Morro shoulderband snail as described in...

  17. 76 FR 41811 - Kellaway Proposed Low-Effect Habitat Conservation Plan for the Morro Shoulderband Snail, San Luis...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... Shoulderband Snail, San Luis Obispo County, CA AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice of... ``take'' of the Federally endangered Morro shoulderband snail (Helminthoglypta walkeriana) incidental to..., which includes the Kellaway Low-Effect Habitat Conservation Plan for the Morro Shoulderband Snail...

  18. 78 FR 14587 - Kelley-McDonough Low-Effect Habitat Conservation Plan for the Morro Shoulderband Snail, Community...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-06

    ... Shoulderband Snail, Community of Los Osos, San Luis Obispo County, California AGENCY: Fish and Wildlife Service... potential for ``take'' of the federally endangered Morro shoulderband snail that is likely to occur... that are likely to result in take of the Morro shoulderband snail as described in their plan. We...

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

    ERIC Educational Resources Information Center

    Stewart, Timothy W.

    2007-01-01

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

  20. Single- or mixed-sex Schistosoma japonicum infections of intermediate host snails in hilly areas of Anhui, China.

    PubMed

    Shi, Hui-Ping; Lu, Da-Bing; Shen, Lei; Shi, Tan; Gu, Jian

    2014-02-01

    Schistosomiasis japonicum is one of the most serious communicable diseases, and the transmission of the parasite is dependent of its complex life cycle on which many factors can have an impact. Multiple infections comprising both male and female schistosome within snail intermediate hosts, for example, would facilitate parasite transmission. However, no research on Schistosoma japonicum communities in field-collected Oncomelania hupensis hupensis in relation to schistosome sex has been reported. Therefore, snail survey was performed in a hilly region of Anhui, China, and single- or mixed-sex schistosome infections of snails were detected with final host mouse infection. A total of 8,563 snails were sampled in the field, and 67 were identified with schistosome infections. Of these infected snails, 46 were selected for final host infection. From this, 21 snails were infected with female schistosome, 23 with males and 2 with both males and females. More worms were recovered for snails with mixed-sex infections than with single-sex infection and for snails with male schistosome infection than with female infection (P<0.001). The observed frequency of mixed-sex infections of snails was significantly higher than would be expected if randomly distributed (P<0.01). The ratio male/female of schistosome infections in snails was nearly equal and up to 95.65 % (44/46) of infected snails were single-sex infection. Schistosome infections in snails collected from the hilly area of Anhui Province were not randomly distributed but over-dispersed.

  1. 75 FR 52272 - Endangered and Threatened Wildlife and Plants; Removal of the Utah (Desert) Valvata Snail From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-25

    ... Wildlife and Plants; Removal of the Utah (Desert) Valvata Snail From the Federal List of Endangered and... (Service), are removing the Utah (desert) valvata snail (Valvata utahensis) from the Federal List of... commercial data, we determined that the Utah valvata snail is more widespread and occurs in a greater...

  2. 76 FR 41810 - Francis Proposed Low-Effect Habitat Conservation Plan for the Morro Shoulderband Snail, Los Osos...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... Shoulderband Snail, Los Osos, San Luis Obispo County, CA AGENCY: Fish and Wildlife Service, Interior. ACTION... the potential for ``take'' of the Federally endangered Morro shoulderband snail (Helminthoglypta... includes the Francis Low-Effect Habitat Conservation Plan for the Morro Shoulderband Snail (HCP) that...

  3. 50 CFR 17.45 - Special rules-snails and clams. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 2 2013-10-01 2013-10-01 false Special rules-snails and clams. 17.45 Section 17.45 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—snails and clams....

  4. 50 CFR 17.45 - Special rules-snails and clams. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 2 2011-10-01 2011-10-01 false Special rules-snails and clams. 17.45 Section 17.45 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—snails and clams....

  5. 50 CFR 17.45 - Special rules-snails and clams. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 2 2014-10-01 2014-10-01 false Special rules-snails and clams. 17.45 Section 17.45 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—snails and clams....

  6. 50 CFR 17.45 - Special rules-snails and clams. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 2 2012-10-01 2012-10-01 false Special rules-snails and clams. 17.45 Section 17.45 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—snails and clams....

  7. 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...

  8. 50 CFR 17.45 - Special rules-snails and clams. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 2 2010-10-01 2010-10-01 false Special rules-snails and clams. 17.45 Section 17.45 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—snails and clams....

  9. 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.

  10. Invasive genotypes are opportunistic specialists not general purpose genotypes

    PubMed Central

    Drown, Devin M; Levri, Edward P; Dybdahl, Mark F

    2011-01-01

    It is not clear which forms of plasticity in fitness-related traits are associated with invasive species. On one hand, it may be better to have a robust performance across environments. On the other, it may be beneficial to take advantage of limited favorable conditions. We chose to study a worldwide invasive species, Potamopyrgus antipodarum, and compare the plasticity of life-history traits of a sample of invasive genotypes to a sample of ancestral-range genotypes. We examined the responses to salinity in this freshwater snail because it varies spatially and temporally in the introduced range and contributes to variation in fitness in our system. We used a recently developed statistical method that quantifies aspects of differences in the shape among reaction norms. We found that the invasive lineages survived and reproduced with an increased probability at the higher salinities, and were superior to ancestral-range lineages in only two traits related to reproduction. Moreover, we found that in terms of traits related to growth, the invasive lineages have a performance optimum that is shifted to higher salinities than the ancestral-range lineages as well as having a narrower niche breadth. Contrary to the prediction of the general purpose genotype hypothesis, we found that invasive lineages tended to be opportunistic specialists. PMID:25567958

  11. 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

  12. Cercarial infection in Paludomus petrosus, freshwater snail in Pa La-U Waterfall.

    PubMed

    Krailas, Duangduen; Dechruksa, Wivitchuta; Ukong, Suluck; Janecharut, Tuenta

    2003-06-01

    Paludomus petrosus, the freshwater snails found in Pa La-U Waterfall, were examined for cercarial infection of trematodes. The snails were collected every other month from April, 2001 to February, 2002. Collections were taken from two sampling stations. The counts per unit of time' method was used for collection of the snails. The density of snails was highest in June 2001, and the highest of parasite infection rate was in February 2002. Four types of cercariae were found in the snails: Xiphidiocercariae, Amphistome, Furcocercous cercariae type I, and Furcocercous cercariae type II. Xiphidiocercariae were found in April 2001 to February 2002. Amphistome, Furcocercous cercariae type I and Furcocercous cercariae type II were found in February 2002.

  13. [Neurochemical mechanisms of food aversion conditioning consolidation in snail helix lucorum].

    PubMed

    Solntseva, S V; Nikitin, V P

    2008-08-01

    Effects of cycloheximide, protein synthesis inhibitor as well as serotonin receptor antagonist and NMDA receptor antagonist, on food aversion conditioning consolidation were studied in snail Helix lucorum. Food aversion conditioning was absent in snails after application of cycloheximide. Repeated training produced no food aversion conditioning for the same type of food in these snails without cycloheximide application. Food aversion conditioning was absent in snails after metiotepin, nonselective serotonin receptors antagonist, or after MK-801, NMDA glutamate receptors antagonist, applications. At the same time, repeated training produced facilitated food aversion conditioning for the same type of food in these snails. Our experiments were the first which showed that effect on different molecular mechanisms evoked reversible or irreversible disruption of long-term memory consolidation during the same learning. It was suggested that suppression of retrieval produced reversible effect whereas disruption of memory storage initiated irreversible effect on long-term memory consolidation.

  14. [Neurochemical mechanisms of food aversion conditioning consolidation in snail Helix lucorum].

    PubMed

    Solntseva, S V; Nikitin, v P

    2008-11-01

    Effects of cycloheximide, protein synthesis inhibitors, as well as serotonin receptor antagonist and NMDA receptor antagonist on food aversion conditioning consolidation were studied in snail Helix lucorum. Food aversion conditioning was absent in snails after application of cycloheximide. Repeated produced no food aversion conditioning for the same type of food in these snails without cycloheximide application. Food aversion conditioning was absent in snails after applications of metiotepin, nonselective serotonin receptors antagonist, or after MK-801, NMDA glutamate receptors antagonist. At the same time, repeated training produced facilitated food aversion conditioning for the same type of food in these snails. Our experiments were the first which showed that effect on different molecular mechanisms evoked reversible or irreversible disruption of long-term memory consolidation during the same learning. It was suggested that suppression of retrieval produced reversible effect, whereas disruption of memory storage initiated irreversible effect on long-term memory consolidation.

  15. Juveniles of Lymnaea 'smart' snails do not perseverate and have the capacity to form LTM.

    PubMed

    Shymansky, Tamila; Protheroe, Amy; Hughes, Emily; Swinton, Cayley; Swinton, Erin; Lukowiak, Kai S; Phillips, Iain; Lukowiak, Ken

    2017-02-01

    Previously, it was concluded that the nervous systems of juvenile snails were not capable of mediating long-term memory (LTM). However, exposure and training of those juvenile snails in the presence of a predator cue significantly altered their ability to learn and form LTM. In addition, there are some strains of Lymnaea which have been identified as 'smart'. These snails form LTM significantly better than the lab-bred strain. Here, we show that juveniles of two smart snail strains not only are capable of associative learning but also have the capacity to form LTM following a single 0.5 h training session. We also show that freshly collected 'wild' 'average' juveniles are also not able to form LTM. Thus, the smart snail phenotype in these strains is expressed in juveniles.

  16. Phenotypic plasticity in the common garden snail: big guts and heavier mucus glands compete in snails faced with the dual challenge of poor diet and coarse substrate.

    PubMed

    Munn, Adam J; Treloar, Marguerite

    2016-12-26

    Phenotypic plasticity allows animals to manage environmental challenges. Studies aimed at quantifying plasticity often focus on one challenge, such as diet, and one organ system, such the gastrointestinal tract, but this approach may not adequately reflect how plasticity could buffer multiple challenges. Thus, we investigated the outcomes of a dual challenge experiment that fed land snails either a high-fibre (low quality) or a low-fibre (high quality) diet, and simultaneously exercised them daily over 1.2 m on either a smooth surface of polyvinyl chloride (PVC) or a rough sandpaper. By the end of 20 days, snails fed the poor quality diet had a longer crop and oesophagus and a heavier intestine and rectum than those offered a low-fibre diet. Additionally, high-fibre fed snails had a smaller spermoviduct and oviduct. When also exercised on sandpaper, high-fibre fed snails had a smaller digestive gland, a main energy store, than those exercised on PVC. All snails exercised on sandpaper had a heavier pedal mucus gland, used a loping gait and used less mucus than those on PVC plastic, but there was no difference in the average speed of snails on either surface, supporting the conclusion that loping is a mucus conserving gait. Notably, snails faced with both a diet and substrate challenge had a smaller kidney, which could directly effect fecundity. This demonstrates that our dual challenge approach has potential for evaluating the costs and limits of the plasticity necessary to fully appreciate the evolutionary significance of plasticity in snails and other species.

  17. Snail family members and cell survival in physiological and pathological cleft palates.

    PubMed

    Martínez-Alvarez, Concepción; Blanco, María J; Pérez, Raquel; Rabadán, M Angeles; Aparicio, Marta; Resel, Eva; Martínez, Tamara; Nieto, M Angela

    2004-01-01

    Palate fusion is a complex process that involves the coordination of a series of cellular changes including cell death and epithelial to mesenchymal transition (EMT). Since members of the Snail family of zinc-finger regulators are involved in both triggering of the EMT and cell survival, we decided to study their putative role in palatal fusion. Furthermore, Snail genes are induced by transforming growth factor beta gene (TGF-beta) superfamily members, and TGF-beta(3) null mutant mice (TGF-beta(3)-/-) show a cleft palate phenotype. Here we show that in the wild-type mouse at the time of fusion, Snail is expressed in a few cells of the midline epithelial seam (MES), compatible with a role in triggering of the EMT in a small subpopulation of the MES. We also find an intriguing relationship between the expression of Snail family members and cell survival associated to the cleft palate condition. Indeed, Snail is expressed in the medial edge epithelial (MEE) cells in TGF-beta(3)-/-mouse embryo palates, where it is activated by the aberrant expression of its inducer, TGF-beta(1), in the underlying mesenchyme. In contrast to Snail-deficient wild-type pre-adhesion MEE cells, Snail-expressing TGF-beta(3) mutant MEE cells survive as they do their counterparts in the chick embryo. Interestingly, Slug is the Snail family member expressed in the chick MEE, providing another example of interchange of Snail and Slug expression between avian and mammalian embryos. We propose that in the absence of TGF-beta(3), TGF-beta(1) is upregulated in the mesenchyme, and that in both physiological (avian) and pathological (TGF-beta(3)-/-mammalian) cleft palates, it induces the expression of Snail genes promoting the survival of the MEE cells and permitting their subsequent differentiation into keratinized stratified epithelium.

  18. 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

  19. 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.

  20. Downregulation of tumor suppressing STF cDNA 3 promotes epithelial-mesenchymal transition and tumor metastasis of osteosarcoma by the Wnt/GSK-3β/β-catenin/Snail signaling pathway.

    PubMed

    Lv, Yang-fan; Dai, Huanzi; Yan, Guang-ning; Meng, Gang; Zhang, Xi; Guo, Qiao-nan

    2016-04-10

    Epithelial to mesenchymal transition (EMT) has received considerable attention as a conceptual paradigm for explaining the invasive and metastatic behavior of cells during cancer progression. Our previous study showed that loss of expression of TSSC3 is positively associated with osteosarcoma malignancy and progression. However, whether TSSC3 mediates EMT in osteosarcoma is poorly understood. In the present study, we determined that TSSC3 downregulation induced cell migration and invasion ability and promoted mesenchymal transition of osteosarcoma cells by upregulating mesenchymal markers and inhibiting the epithelial markers. Furthermore, TSSC3 downregulation elicited a signaling cascade that included increased levels of Wnt3a and LRP5, inactivation of GSK-3β, accumulation of nuclear β-catenin and Snail, the augmented binding of β-catenin to TCF-4, and accordingly increased the expression of Wnt target genes (CD44, MMP7). The gene knockdown of these signaling proteins could inhibit TSSC3 downregulation-promoted EMT, migration, and invasion in osteosarcoma. Finally, TSSC3 overexpression obviously inhibited cell migration, invasion, and repressed mesenchymal phenotypes, reducing lung metastasis through GSK-3β activation. Collectively, TSSC3 downregulation promotes the EMT of osteosarcoma cells by regulating EMT markers via a signal transduction pathway that involves Snail, Wnt-β-catenin/TCF, and GSK-3β.

  1. Selective and universal primers for trematode barcoding in freshwater snails.

    PubMed

    Routtu, J; Grunberg, D; Izhar, R; Dagan, Y; Guttel, Y; Ucko, M; Ben-Ami, F

    2014-07-01

    Trematodes are significant pathogens of high medical, veterinary, and environmental importance. They are hard to isolate from their intermediate hosts, and their early life stages are difficult to identify morphologically. Therefore, primers were developed for trematodes to create a species barcoding system and allow selective PCR amplification in mixed samples. The specific oligonucleotide primer was universal for trematodes that infected several freshwater snail species in Israel. The diagnostic tool is based on the 18S rDNA gene. In contrast to morphological identification, trematode barcoding is rapid as it is based on a sequence of only 800 bp, and it classifies species accurately due to high polymorphism between conserved areas.

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

    PubMed

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

    2010-01-01

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

  3. Xanthine oxidase and xanthine dehydrogenase from an estivating land snail.

    PubMed

    Hermes-Lima, M; Storey, K B

    1995-01-01

    During arousal from estivation in land snails, Otala lactea, active metabolic functions are restored within minutes and oxygen consumption increases dramatically. During the transition from the hypoxic conditions of estivation to normoxia it is possible that xanthine oxidase (XO) in hepatopancreas contributes to the observed lipid peroxidation. Using a fluorometric assay that is based on the oxidation of pterin, the activities and some properties of XO and XO+XDH (sum of XO and xanthine dehydrogenase activities) were measured in hepatopancreas extracts. Km values for pterin for XO and XO+XDH were 9 and 6 microM, respectively, and the Km of XDH for methylene blue was 5 microM. Both XO+XDH and XO activities were inhibited by allopurinol (I50 = 2 microM), pre-incubation at 40 degrees C, and by 5 min H2O2 pre-exposure. Inclusion of azide in the reaction promoted a rise of approximately 70-fold in the inactivation power of H2O2 due to inhibition of high endogenous catalase activity. The I50 for H2O2 of XO+XDH and XO activities in the presence of azide was 0.04 and 0.11 mM, respectively. Unlike the situation for mammalian XO, a previous reduction of O. lactea XO (by pterin) was not necessary to make the enzyme susceptible to H2O2 effects. Interestingly, methylene blue partially prevented both heat- and H2O2-induced inactivation of XO+XDH activity. These data indicate that the formation of an enzyme-methylene blue complex induces protection against heat and oxidative damage at the FAD-active site. Both XO and XO+XDH activites were significantly higher in snails after 35 days of estivation compared with active snails 24 h after arousal from dormancy. The ratio of XO/(XO+XDH) activities was also slightly increased in estivating O. lactea (from 0.07 to 0.09; P < 0.025). XO activity was 0.03 nmol.min-1.mg protein-1 in estivating snails. Compared with hepatopancreas catalase, XO activity is probably too low to contribute significantly to the net generation of oxyradicals, and

  4. Exposure to parasites increases promiscuity in a freshwater snail

    PubMed Central

    Soper, D. M.; King, K. C.; Vergara, D.; Lively, C. M.

    2014-01-01

    Under the Red Queen hypothesis, outcrossing can produce genetically variable progeny, which may be more resistant, on average, to locally adapted parasites. Mating with multiple partners may enhance this resistance by further increasing the genetic variation among offspring. We exposed Potamopyrgus antipodarum to the eggs of a sterilizing, trematode parasite and tested whether this altered mating behaviour. We found that exposure to parasites increased the number of snail mating pairs and the total number of different mating partners for both males and females. Thus, our results suggest that, in host populations under parasite-mediated selection, exposure to infective propagules increases the rate of mating and the number of mates. PMID:24759366

  5. Therapeutic potential of cone snail venom peptides (conopeptides).

    PubMed

    Vetter, Irina; Lewis, Richard J

    2012-01-01

    Cone snails have evolved many 1000s of small, structurally stable venom peptides (conopeptides) for prey capture and defense. Whilst < 0.1% have been pharmacologically characterised, those with known function typically target membrane proteins of therapeutic importance, including ion channels, transporters and GPCRs. Several conopeptides reduce pain in animals models, with one in clinical development (χ-conopeptide analogue Xen2174) and one marketed (ω- conotoxin MVIIA or Prialt) for the treatment of severe pain. In addition to their therapeutic potential, conopeptides have been valuable probes for studying the role of a number of key membrane proteins in normal and disease physiology.

  6. Metastasis-associated protein 1 promotes tumor invasion by downregulation of E-cadherin.

    PubMed

    Weng, Wenhao; Yin, Jiayi; Zhang, Yue; Qiu, Jin; Wang, Xinghe

    2014-03-01

    Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors. Upregulation of metastasis-associated protein 1 (MTA1) has been reported to contribute to the development of esophageal squamous cell carcinoma. Therefore, the objective of our study was to identify the molecular mechanisms of MTA1 underlying the invasion and metastasis of ESCC. We overexpressed MTA1 in ESCC cells to examine the role of MTA1 in the regulation of the cell invasion. In addition, using luciferase reporter assay and electrophoretic mobility shift assays, we evaluated the binding of MTA1 to the promoter of E-cadherin. We found that MTA1 overexpression promotes invasiveness of the human esophageal carcinoma cell line EC-9706. This effect was accompanied by downregulation of the epithelial cell marker E-cadherin and upregulation of vimentin and MMP-9 luciferase reporter assays showed that MTA1 inhibited the promoter activity of E-cadherin and that this was dependent on Snail, Slug and HDAC1. We also found that Snail and Slug bound the E-boxes in the promoter of E-cadherin and recruited MTA1 and HDAC1 to suppress E-cadherin expression, as confirmed by electrophoretic mobility shift and chromatin immunoprecipitation assays. MTA1 promotes tumor invasion by downregulation of E-cadherin. These results demonstrate a novel role for MTA1 in the regulation of esophageal squamous cell carcinoma invasion and provide insight into the mechanisms involved in this process.

  7. Esophagectomy - minimally invasive

    MedlinePlus

    Minimally invasive esophagectomy; Robotic esophagectomy; Removal of the esophagus - minimally invasive; Achalasia - esophagectomy; Barrett esophagus - esophagectomy; Esophageal cancer - esophagectomy - laparoscopic; Cancer of the ...

  8. Diaphanous gene mutation affects spiral cleavage and chirality in snails

    PubMed Central

    Kuroda, Reiko; Fujikura, Kohei; Abe, Masanori; Hosoiri, Yuji; Asakawa, Shuichi; Shimizu, Miho; Umeda, Shin; Ichikawa, Futaba; Takahashi, Hiromi

    2016-01-01

    L-R (left and right) symmetry breaking during embryogenesis and the establishment of asymmetric body plan are key issues in developmental biology, but the onset including the handedness-determining gene locus still remains unknown. Using pure dextral (DD) and sinistral (dd) strains of the pond snail Lymnaea stagnalis as well as its F2 through to F10 backcrossed lines, the single handedness-determining-gene locus was mapped by genetic linkage analysis, BAC cloning and chromosome walking. We have identified the actin-related diaphanous gene Lsdia1 as the strongest candidate. Although the cDNA and derived amino acid sequences of the tandemly duplicated Lsdia1 and Lsdia2 genes are very similar, we could discriminate the two genes/proteins in our molecular biology experiments. The Lsdia1 gene of the sinistral strain carries a frameshift mutation that abrogates full-length LsDia1 protein expression. In the dextral strain, it is already translated prior to oviposition. Expression of Lsdia1 (only in the dextral strain) and Lsdia2 (in both chirality) decreases after the 1-cell stage, with no asymmetric localization throughout. The evolutionary relationships among body handedness, SD/SI (spiral deformation/spindle inclination) at the third cleavage, and expression of diaphanous proteins are discussed in comparison with three other pond snails (L. peregra, Physa acuta and Indoplanorbis exustus). PMID:27708420

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

    PubMed Central

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

    2014-01-01

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

  10. Snail Family Transcription Factors Are Implicated in Thyroid Carcinogenesis

    PubMed Central

    Hardy, Robert G.; Vicente-Dueñas, Carolina; González-Herrero, Ines; Anderson, Catriona; Flores, Teresa; Hughes, Sharon; Tselepis, Chris; Ross, James A.; Sánchez-García, Isidro

    2007-01-01

    E-Cadherin (CDH1) expression is reduced in thyroid carcinomas by primarily unknown mechanisms. In several tissues, SNAIL (SNAI1) and SLUG (SNAI2) induce epithelial-mesenchymal transition by altering target gene transcription, including CDH1 repression, but these transcription factors have not been studied in thyroid carcinoma. Recently, our group has provided direct evidence that ectopic SNAI1 expression induces epithelial and mesenchymal mouse tumors. SNAI1, SNAI2, and CDH1 expression were analyzed in thyroid-derived cell lines and samples of human follicular and papillary thyroid carcinoma by reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry. The effect of SNAI1 expression on CDH1 transcription was analyzed by reverse transcriptase-polymerase chain reaction and Western blotting in ori-3 cells. Thyroid carcinoma development was analyzed in CombitTA-Snail mice, in which SNAI1 levels are up-regulated. SNAI1 and SNAI2 were not expressed in cells derived from normal thyroid tissue, or in normal human thyroid samples, but were highly expressed in cell lines derived from thyroid carcinomas, in human thyroid carcinoma samples, and their metastases. SNAI1 expression in ori-3 cells repressed CDH1 transcription. Combi-TA mice developed papillary thyroid carcinomas, the incidence of which was increased by concomitant radiotherapy. In conclusion, SNAI1 and SNAI2 are ectopically expressed in thyroid carcinomas, and aberrant expression in mice is associated with papillary carcinoma development. PMID:17724139

  11. Reproduction and demography of the Florida Everglade (Snail) Kite

    USGS Publications Warehouse

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

    1989-01-01

    An 18-year study of reproduction and survival of the Florida Everglade (Snail) Kite (Rostrhamus sociabilis plumbeus) has revealed the following: extremely poor nesting success (only 13.6% of nests found at the nest-building stage successful); extremely long breeding seasons (some reproductive activity in almost all months in good years); frequent multiple brooding and frequent multiple brooding and frequent renesting after failure; low egg hatchability (81%); high failure rates due to nest collapse, desertion, and predation; extremely high survival of juveniles and adults under good water conditions; and high vulnerability to drought due to near total dependency on a single species of drought-sensitive snail for food. Despite low nesting success, the species has increased rapidly under good conditions, mainly because of multiple nesting attempts within long breeding seasons and high survival rates of free-flying birds. Nesting success varied significantly between regions and nest substrates, but not as a function of seasons or solitary vs. colonial nesting. While nesting success was reduced in low water years, this effect was at least partly due to heavy use of poor nest substrates under such conditions. Clutch size and numbers of young per successful nest varied with regions, but not as a function of seasons or water levels. The effects of coloniality on clutch size and numbers of young were inconsistent. Significant effects of nest-substrate types on clutch size and numbers of young were apparently artifacts of substrate differences between regions.

  12. The snail hosts of schistosomiasis: some evolutionary and ecological perspectives in relation to control.

    PubMed

    Thomas, J D

    1995-01-01

    Despite opportunities for radiation provided by spatio-temporal isolation, the basic morphological plan of pulmonate snails has remained conservative. In consequence of the resulting dearth of morphological characters and their plasticity, there is a case for using biochemical characters such as exogenous chemicals released by the snails (e.g. amino acids) and their chemoreception niche as taxonomic aids to classify snails of medical importance. As these same chemicals are used by snails to distinguish conspecifics they could also be used as "environmental antibodies" in controlled release formulations (CRF's) designed to remove target snails in a specific, cost-effective and ecologically acceptable manner. The snails, surface-living bacteria, algae and macrophytic plants are considered as co-evolved, interactive modular systems with strong mutualistic elements. Recently, anthropogenic perturbations such as deforestation, and damming of flowing waters, have benefited these modules whereas others such as river canalization, acid deposition, accumulation of pesticide residues and eutrophication have harmed them. Research is needed to elucidate the factors which limit the growth of snails in primitive habitats, uninfluenced by man, as well as in those subject to harmful anthropogenic factors. The understanding thus gained could be applied to develop cost-effective primary health care strategies to reduce or prevent transmission of schistosomiasis and other water related diseases.

  13. Nrf2 inhibits epithelial-mesenchymal transition by suppressing snail expression during pulmonary fibrosis

    PubMed Central

    Zhou, Wencheng; Mo, Xiaoting; Cui, Wenhui; Zhang, Zhihui; Li, Delin; Li, Liucheng; Xu, Liang; Yao, Hongwei; Gao, Jian

    2016-01-01

    Epithelial-mesenchymal transition (EMT) is a phenotype conversion that plays a critical role in the development of pulmonary fibrosis (PF). It is known that snail could regulate the progression of EMT. Nuclear factor erythroid 2 related factor 2 (Nrf2), a key regulator of antioxidant defense system, protects cells against oxidative stress. However, it is not known whether Nrf2 regulates snail thereby modulating the development of PF. Here, bleomycin (BLM) was intratracheally injected into both Nrf2-knockout (Nrf2−/−) and wild-type mice to compare the development of PF. Rat type II alveolar epithelial cells (RLE-6TN) were treated with a specific Nrf2 activator sulforaphane, or transfected with Nrf2 and snail siRNAs to determine their effects on transforming growth factor β1 (TGF-β1)-induced EMT. We found that BLM-induced EMT and lung fibrosis were more severe in Nrf2−/− mice compared to wild-type mice. In vitro, sulforaphane treatment attenuated TGF-β1-induced EMT, accompanied by the down-regulation of snail. Inversely, silencing Nrf2 by siRNA enhanced TGF-β1-induced EMT along with increased expression of snail. Interestingly, when snail was silenced by siRNA, sulforaphane treatment was unable to reduce the progression of EMT in RLE-6TN cells. These findings suggest that Nrf2 attenuates EMT and fibrosis process by regulating the expression of snail in PF. PMID:27982105

  14. 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

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

    PubMed

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

    2015-01-01

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

  16. 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.

  17. 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.

  18. Phosphorylation of eIF4E promotes EMT and metastasis via translational control of SNAIL and MMP-3

    PubMed Central

    Robichaud, Nathaniel; del Rincon, Sonia V.; Huor, Bonnie; Alain, Tommy; Petruccelli, Andy; Hearnden, Jaclyn; Goncalves, Christophe; Grotegut, Stefan; Spruck, Charles H.; Furic, Luc; Larsson, Ola; Miller, Wilson H.; Sonenberg, Nahum

    2016-01-01

    The progression of cancers from primary tumors to invasive and metastatic stages accounts for the overwhelming majority of cancer deaths. Understanding the molecular events which promote metastasis is thus critical in the clinic. Translational control is emerging as an important factor in tumorigenesis. The mRNA cap-binding protein eIF4E is an oncoprotein that plays an important role in cancer initiation and progression. eIF4E must be phosphorylated to promote tumor development. However, the role of eIF4E phosphorylation in metastasis is not known. Here, we show that mice in which eIF4E cannot be phosphorylated are resistant to lung metastases in a mammary tumor model, and that cells isolated from these mice exhibit impaired invasion. We also demonstrate that TGFβ induces eIF4E phosphorylation to promote translation of Snail and Mmp-3 mRNAs, and the induction of epithelial-to-mesenchymal transition (EMT). Furthermore, we describe a new model wherein EMT induced by TGFβ requires translational activation via the non-canonical TGFβ signaling branch acting through eIF4E phosphorylation. PMID:24909168

  19. Rab25 acts as an oncogene in luminal B breast cancer and is causally associated with Snail driven EMT

    PubMed Central

    Mitra, Shreya; Federico, Lorenzo; Zhao, Wei; Dennison, Jennifer; Sarkar, Tapasree Roy; Zhang, Fan; Takiar, Vinita; Cheng, Kwai W.; Mani, Sendurai; Lee, Ju Seog; Mills, Gordon B.

    2016-01-01

    The Rab GTPases regulate vesicular trafficking machinery that transports and delivers a diverse pool of cargo, including growth factor receptors, integrins, nutrient receptors and junction proteins to specific intracellular sites. The trafficking machinery is indeed a major posttranslational modifier and is critical for cellular homeostasis. Deregulation of this stringently controlled system leads to a wide spectrum of disorders including cancer. Herein we demonstrate that Rab25, a key GTPase, mostly decorating the apical recycling endosome, is a dichotomous variable in breast cancer cell lines with higher mRNA and protein expression in Estrogen Receptor positive (ER+ve) lines. Rab25 and its effector, Rab Coupling Protein (RCP) are frequently coamplified and coordinately elevated in ER+ve breast cancers. In contrast, Rab25 levels are decreased in basal-like and almost completely lost in claudin-low tumors. This dichotomy exists despite the presence of the 1q amplicon that hosts Rab25 across breast cancer subtypes and is likely due to differential methylation of the Rab25 promoter. Functionally, elevated levels of Rab25 drive major hallmarks of cancer including indefinite growth and metastasis but in case of luminal B breast cancer only. Importantly, in such ER+ve tumors, coexpression of Rab25 and its effector, RCP is significantly associated with a markedly worsened clinical outcome. Importantly, in claudin-low cell lines, exogenous Rab25 markedly inhibits cell migration. Similarly, during Snail-induced epithelial to mesenchymal transition (EMT) exogenous Rab25 potently reverses Snail-driven invasion. Overall, this study substantiates a striking context dependent role of Rab25 in breast cancer where Rab25 is amplified and enhances aggressiveness in luminal B cancers while in claudin-low tumors, Rab25 is lost indicating possible anti-tumor functions. PMID:27259233

  20. Combinatorial peptide libraries in drug design: lessons from venomous cone snails.

    PubMed

    Olivera, B M; Hillyard, D R; Marsh, M; Yoshikami, D

    1995-10-01

    Many present-day drugs are derived from compounds that are natural products, a traditional source of which is fermentation broths of microorganisms. The venoms of cone snails are a new natural resource of peptides that may have a pharmaceutical potential equivalent to those from traditional sources, particularly for developing drugs that target cell-surface receptors or ion channels. In effect, cone snails have used a combinatorial library strategy to evolve their small, highly bioactive venom peptides. The methods by which the snails have generated thousands of peptides with remarkable specificity and high affinity for their targets may provide important lessons in designing combinatorial libraries for drug development.

  1. Multiple infection of amber Succinea putris snails with sporocysts of Leucochloridium spp. (Trematoda).

    PubMed

    Ataev, G L; Zhukova, A A; Tokmakova, А S; Prokhorova, Е E

    2016-08-01

    Amber Succinea putris snails were collected in the Leningrad Region (Russia). Some of them were infected with trematodes Leucochloridium paradoxum, Leucochloridium perturbatum and Leucochloridium vogtianum. One snail had triple infection with all these species. Genotyping of sporocysts by ITS1-5.8S-ITS2 nucleotide sequences of ribosomal DNA (rDNA) and phylogenetic analysis were performed. The results confirmed the species identification of sporocysts of Leucochloridium based on the shape and colour of mature broodsacs. Sporocyst broodsacs could leave the host snail on their own, remaining viable in the environment for up to an hour. This ability of sporocysts may prevent the excessive infection of the molluscan host.

  2. The Role of B-RAF Mutations in Melanoma and the Induction of EMT via Dysregulation of the NF-κB/Snail/RKIP/PTEN Circuit

    PubMed Central

    Lin, Kimberly; Baritaki, Stavroula; Militello, Loredana; Malaponte, Graziella; Bevelacqua, Ylenia; Bonavida, Benjamin

    2010-01-01

    Melanoma is a highly metastatic cancer, and there are no current therapeutic modalities to treat this deadly malignant disease once it has metastasized. Melanoma cancers exhibit B-RAF mutations in up to 70% of cases. B-RAF mutations are responsible, in large part, for the constitutive hyperactivation of survival/antiapoptotic pathways such as the MAPK, NF-κB, and PI3K/AKT. These hyperactivated pathways regulate the expression of genes targeting the initiation of the metastatic cascade, namely, the epithelial to mesenchymal transition (EMT). EMT is the result of the expression of mesenchymal gene products such as fibronectin, vimentin, and metalloproteinases and the invasion and inhibition of E-cadherin. The above pathways cross-talk and regulate each other’s activities and functions. For instance, the NF-κB pathway directly regulates EMT through the transcription of gene products involved in EMT and indirectly through the transcriptional up-regulation of the metastasis inducer Snail. Snail, in turn, suppresses the expression of the metastasis suppressor gene product Raf kinase inhibitor protein RKIP (inhibits the MAPK and the NF-κB pathways) as well as PTEN (inhibits the PI3K/AKT pathway). The role of B-RAF mutations in melanoma and their direct role in the induction of EMT are not clear. This review discusses the hypothesis that B-RAF mutations are involved in the dysregulation of the NF-κB/Snail/RKIP/PTEN circuit and in both the induction of EMT and metastasis. The therapeutic implications of the dysregulation of the above circuit by B-RAF mutations are such that they offer novel targets for therapeutic interventions in the treatment of EMT and metastasis. PMID:20827424

  3. Fossil land snails of East Africa and their palaeoecological significance

    NASA Astrophysics Data System (ADS)

    Pickford, Martin

    1995-04-01

    This study deals with the Neogene and extant land snails of tropical East Africa and their implications for interpreting the paleoenvironments of the numerous localities at which they have been found. Of major significance to the study is the intimate association between the terrestrial molluscs and the rich mammalian faunas, hominoids included, of East Africa. Thus, palaeoecological reconstructions based on land snails are directly applicable to the mammalian faunas. Palaeoecological reconstructions are proposed for most of the Lower and Middle Miocene hominoids, including Proconsul, Rangwapithecus, Limnopithecus, Micropithecus, Nyanzapithecus, Kenyapithecus and others, and for the mid-Pliocene Australopithecus from Laetoli, Tanzania. The departure point for the palaeoecological reconstructions is a comprehensive study of extant terrestrial molluscs of East Africa, the habitat preferences of which are well documented. All the fossil gastropods studied comprise extant genera and even species, so the usual problems regarding the application of actualism to fossil assemblages is avoided. Furthermore, the fossil gastropod assemblages resemble extant ones, confirming their utility for such reconstructions. Among the parameters examined are rainfall, altitude, vegetation cover and type and zoogeography. A further point of interest is that the samples are more than adequate for the purposes of the study, many of the fossil localities having yielded several thousand specimens. Finally, more than 40% of the extant genera of East Africa have now been recognized in the fossil state. The molluscs are thus, by far, the best represented biological group known in the fossil record of Africa and as such hold great potential for understanding the past. This study ends with reconstructions of the palaeoecology of numerous fossiliferous localities in East Africa which have yielded molluscs and mammals. Changes through the geological column are documented and the habitat preferences

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

    PubMed Central

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

    2013-01-01

    Accumulating evidence indicates that epithelial-to-mesenchymal transition (EMT) might be a key event for cancer progression. The upregulation of Snail1, one of the most extensively studied EMT regulators, has been implicated in cancer metastasis, but the underlying mechanisms remain unclear. This study aims to identify that Snail1 targets regulating EMT-associated cancer cell migration. Human lung carcinoma A549 cells were treated with transforming growth factor beta 1 (TGF-β1), and EMT-associated phenotypic and functional alterations were monitored. TGF-β1 induced typical EMT-like morphological changes, ‘cadherin switching' and cell migration in A549 cells. TGF-β1 stimulation induced rapid and persistent upregulation of Snail1. Moreover, Snail1 upregulation was required for EMT-associated cell migration. Several metastasis suppressors with putative Snail1-binding sites in their promoters were dramatically repressed in A549 cells during TGF-β1-induced EMT. Gain- and loss-of Snail1 function experiments demonstrated that scavenger receptor class A member 5 (SCARA5) was negatively regulated by Snail1. Importantly, SCARA5 downregulation was essential for EMT-induced migration in A549 cells. The chromatin immunoprecipitation assay revealed that Snail1 could bind to the E-box elements in SCARA5 promoter, implying that SCARA5 is a direct Snail1 target modulating cancer cell mobility during EMT. In addition, we showed that DNA methyltransferase 1 was physically associated with Snail1 to silence SCARA5 expression with an unidentified DNA methylation-independent mechanism, suggesting the complexity of Snail1-mediated epigenetic regulation. Collectively, our data demonstrated that EMT-regulator Snail1 suppresses the expression of SCARA5 to promote cancer progression, highlighting the possibility to target Snail1 and SCARA5 for cancer treatment. PMID:24061576

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

    PubMed

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

    2013-09-23

    Accumulating evidence indicates that epithelial-to-mesenchymal transition (EMT) might be a key event for cancer progression. The upregulation of Snail1, one of the most extensively studied EMT regulators, has been implicated in cancer metastasis, but the underlying mechanisms remain unclear. This study aims to identify that Snail1 targets regulating EMT-associated cancer cell migration. Human lung carcinoma A549 cells were treated with transforming growth factor beta 1 (TGF-β1), and EMT-associated phenotypic and functional alterations were monitored. TGF-β1 induced typical EMT-like morphological changes, 'cadherin switching' and cell migration in A549 cells. TGF-β1 stimulation induced rapid and persistent upregulation of Snail1. Moreover, Snail1 upregulation was required for EMT-associated cell migration. Several metastasis suppressors with putative Snail1-binding sites in their promoters were dramatically repressed in A549 cells during TGF-β1-induced EMT. Gain- and loss-of Snail1 function experiments demonstrated that scavenger receptor class A member 5 (SCARA5) was negatively regulated by Snail1. Importantly, SCARA5 downregulation was essential for EMT-induced migration in A549 cells. The chromatin immunoprecipitation assay revealed that Snail1 could bind to the E-box elements in SCARA5 promoter, implying that SCARA5 is a direct Snail1 target modulating cancer cell mobility during EMT. In addition, we showed that DNA methyltransferase 1 was physically associated with Snail1 to silence SCARA5 expression with an unidentified DNA methylation-independent mechanism, suggesting the complexity of Snail1-mediated epigenetic regulation. Collectively, our data demonstrated that EMT-regulator Snail1 suppresses the expression of SCARA5 to promote cancer progression, highlighting the possibility to target Snail1 and SCARA5 for cancer treatment.

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

    PubMed Central

    2014-01-01

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

  7. Snail reprograms glucose metabolism by repressing phosphofructokinase PFKP allowing cancer cell survival under metabolic stress.

    PubMed

    Kim, Nam Hee; Cha, Yong Hoon; Lee, Jueun; Lee, Seon-Hyeong; Yang, Ji Hye; Yun, Jun Seop; Cho, Eunae Sandra; Zhang, Xianglan; Nam, Miso; Kim, Nami; Yuk, Young-Su; Cha, So Young; Lee, Yoonmi; Ryu, Joo Kyung; Park, Sunghyouk; Cheong, Jae-Ho; Kang, Sang Won; Kim, Soo-Youl; Hwang, Geum-Sook; Yook, Jong In; Kim, Hyun Sil

    2017-02-08

    Dynamic regulation of glucose flux between aerobic glycolysis and the pentose phosphate pathway (PPP) during epithelial-mesenchymal transition (EMT) is not well-understood. Here we show that Snail (SNAI1), a key transcriptional repressor of EMT, regulates glucose flux toward PPP, allowing cancer cell survival under metabolic stress. Mechanistically, Snail regulates glycolytic activity via repression of phosphofructokinase, platelet (PFKP), a major isoform of cancer-specific phosphofructokinase-1 (PFK-1), an enzyme involving the first rate-limiting step of glycolysis. The suppression of PFKP switches the glucose flux towards PPP, generating NADPH with increased metabolites of oxidative PPP. Functionally, dynamic regulation of PFKP significantly potentiates cancer cell survival under metabolic stress and increases metastatic capacities in vivo. Further, knockdown of PFKP rescues metabolic reprogramming and cell death induced by loss of Snail. Thus, the Snail-PFKP axis plays an important role in cancer cell survival via regulation of glucose flux between glycolysis and PPP.

  8. Specificity of Mechanisms of Memory Reconsolidation in Snails Trained for Rejection of Two Types of Food.

    PubMed

    Nikitin, V P; Kozyrev, S A; Solntseva, S V

    2017-01-01

    Specificity of behavioral and neuronal mechanisms of impairment of long-term memory reconsolidation was studied in edible snails trained for associative skill of rejection of two types of food: raw carrots (conditioned stimulus 1) and apple (conditioned stimulus 2). In 2 days after training, the snails received protein synthesis inhibitor cycloheximide and a reminder (conditioned stimulus 1 or 2). In 3 and 14 days after cycloheximide/reminder, we observed the absence of aversive responses to the conditioned stimulus used as the reminder and preserved responses to the conditioned stimulus not used as the reminder. Moreover, we observed specific suppression of synaptic responses of command neurons of snail defensive behavior induced by the conditioned stimulus used as the reminder after cycloheximide injection and preserved synaptic responses of neurons to the other conditioned stimulus. It was hypothesized that protein synthesis-dependent synapse-specific plasticity of command neurons can be a mechanism of selective preservation of conditioned food aversion memory in snails.

  9. Susceptibility of Iraqi fresh water snails to infection with Schistosoma haematobium and Schistosoma mansoni Egyptian strains.

    PubMed

    Wajdi, N A; Hussain, W I; El-Hawary, M F

    1979-01-01

    A great number of Egyptian workers and farmers are seeking settlement in Iraq and some of them proved to have either Schistosoma Haematobium (S.h.) or Schistosoma mansoni (S.m) or even mixed infection. Besides, there is the possibility that some of the Iraqi fresh water snails may prove to be susceptible to infection by one or both of the Schistosoma Egyptian strains. The present study deals with investigations on the susceptibility of Iraqi B. truncatus, Gyranaulus ehrenbergi, Physa c.f. fontinalis, Lymnea lagetis, Melanoides tuberculata and Melanopsis nodes by these parasites. Egyptian S. haematobium but not Egyptian S. mansoni infect Iraqi B. truncatus and both proved to be unable to infect any of the other snails included in the study. Yet, the number of cercariae shedded by B. truncatus snails infected with the Egyptian S. haematobium strain, was much less that the number of cercariae shedded by these snails when infected with the Iraqi S. Haematobium strain.

  10. Behavioural responses of the snail Lymnaea acuminata to carbohydrates and amino acids in bait pellets.

    PubMed

    Agrahari, P; Singh, D K

    2010-12-01

    Snail control could play an important role in programmes against fascioliasis, especially if the methods used for molluscicide delivery could be improved, such as by the development of bait formulations containing both an effective attractant and a molluscicide, to ensure good levels of contact between the molluscicide and the target snail populations. In a recent study, the attractiveness to Lymnaea acuminata (an intermediate host of the digenean trematode Fasciola gigantica) of potential components of snail-attractant pellets was investigated. Carbohydrates (glucose, maltose, sucrose or starch, each at 10 mM) and amino acids (citrulline, tryptophan, proline or serine, each at 20 mM), were tested in aquaria, with the snails initially placed 22.5, 30 or 45 cm from an agar pellet containing the component under test. Under these conditions, starch and proline emerged as the strongest attractants for L. acuminata, followed by maltose and serine.

  11. Elongator Protein 3 (Elp3) stabilizes Snail1 and regulates neural crest migration in Xenopus

    PubMed Central

    Yang, Xiangcai; Li, Jiejing; Zeng, Wanli; Li, Chaocui; Mao, Bingyu

    2016-01-01

    Elongator protein 3 (Elp3) is the enzymatic unit of the elongator protein complex, a histone acetyltransferase complex involved in transcriptional elongation. It has long been shown to play an important role in cell migration; however, the underlying mechanism is unknown. Here, we showed that Elp3 is expressed in pre-migratory and migrating neural crest cells in Xenopus embryos, and knockdown of Elp3 inhibited neural crest cell migration. Interestingly, Elp3 binds Snail1 through its zinc-finger domain and inhibits its ubiquitination by β-Trcp without interfering with the Snail1/Trcp interaction. We showed evidence that Elp3-mediated stabilization of Snail1 was likely involved in the activation of N-cadherin in neural crest cells to regulate their migratory ability. Our findings provide a new mechanism for the function of Elp3 in cell migration through stabilizing Snail1, a master regulator of cell motility. PMID:27189455

  12. Gastropod-Borne Helminths: A Look at the Snail-Parasite Interplay.

    PubMed

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

    2016-03-01

    More than 300 million people suffer from a range of diseases caused by gastropod-borne helminths, predominantly flatworms and roundworms, whose life cycles are characterized by a diversified ecology and epidemiology. Despite the plethora of data on these parasites, very little is known of the fundamental biology of their gastropod intermediate hosts, or of the interactions occurring at the snail-helminth interface. In this article, we focus on schistosomes and metastrongylids of human and animal significance, and review current knowledge of snail-parasite interplay. Future efforts aimed at elucidating key elements of the biology and ecology of the snail intermediate hosts, together with an improved understanding of snail-parasite interactions, will aid to identify, plan, and develop new strategies for disease control focused on gastropod intermediate hosts.

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

    PubMed Central

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

    2012-01-01

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

  14. 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

  15. Snail reprograms glucose metabolism by repressing phosphofructokinase PFKP allowing cancer cell survival under metabolic stress

    PubMed Central

    Kim, Nam Hee; Cha, Yong Hoon; Lee, Jueun; Lee, Seon-Hyeong; Yang, Ji Hye; Yun, Jun Seop; Cho, Eunae Sandra; Zhang, Xianglan; Nam, Miso; Kim, Nami; Yuk, Young-Su; Cha, So Young; Lee, Yoonmi; Ryu, Joo Kyung; Park, Sunghyouk; Cheong, Jae-Ho; Kang, Sang Won; Kim, Soo-Youl; Hwang, Geum-Sook; Yook, Jong In; Kim, Hyun Sil

    2017-01-01

    Dynamic regulation of glucose flux between aerobic glycolysis and the pentose phosphate pathway (PPP) during epithelial–mesenchymal transition (EMT) is not well-understood. Here we show that Snail (SNAI1), a key transcriptional repressor of EMT, regulates glucose flux toward PPP, allowing cancer cell survival under metabolic stress. Mechanistically, Snail regulates glycolytic activity via repression of phosphofructokinase, platelet (PFKP), a major isoform of cancer-specific phosphofructokinase-1 (PFK-1), an enzyme involving the first rate-limiting step of glycolysis. The suppression of PFKP switches the glucose flux towards PPP, generating NADPH with increased metabolites of oxidative PPP. Functionally, dynamic regulation of PFKP significantly potentiates cancer cell survival under metabolic stress and increases metastatic capacities in vivo. Further, knockdown of PFKP rescues metabolic reprogramming and cell death induced by loss of Snail. Thus, the Snail-PFKP axis plays an important role in cancer cell survival via regulation of glucose flux between glycolysis and PPP. PMID:28176759

  16. 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.

  17. HSP70 expression in Biomphalaria glabrata snails exposed to cadmium.

    PubMed

    da Silva Cantinha, Rebeca; Borrely, Sueli Ivone; Oguiura, Nancy; de Bragança Pereira, Carlos Alberto; Rigolon, Marcela M; Nakano, Eliana

    2017-06-01

    In this study, the effects of the heavy metal cadmium on the stress protein HSP70 are investigated in freshwater mollusks Biomphalaria glabrata. Adult snails were exposed for 96h to CdCl2 at concentrations ranging from 0.09 to 0.7mgL(-1) (LC50/96h=0.34 (0.30-0.37). Time and concentration-dependent increases in the expression of HSP70 were observed at sub-lethal levels in the immunoblotting assay. Further, an increased survival to a lethal heat shock was observed in animals pre-exposed to a nonlethal concentration of cadmium, evidencing the induction of acquired tolerance. The present study demonstrated the inducibility of B. glabrata HSP70 by cadmium, a relevant environmental contaminant, at non-lethal levels, providing evidences that the assessment of HSP70 in B. glabrata can be regarded as a suitable biomarker for ecotoxicological studies.

  18. Evening roosts of the snail kite in Florida

    USGS Publications Warehouse

    Sykes, P.W.

    1985-01-01

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

  19. Pesticide concentrations in snail kite eggs and nestlings in Florida

    USGS Publications Warehouse

    Sykes, P.W.

    1985-01-01

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

  20. 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.

  1. Optimal designs of mollusk shells from bivalves to snails

    PubMed Central

    Okabe, Takuya; Yoshimura, Jin

    2017-01-01

    Bivalve, ammonite and snail shells are described by a small number of geometrical parameters. Raup noted that the vast majority of theoretically possible shell forms do not occur in nature. The constraint factors that regulate the biased distribution of natural form have long since been an open problem in evolution. The problem of whether natural shell form is a result of optimization remains unsolved despite previous attempts. Here we solve this problem by considering the scaling exponent of shell thickness as a morphological parameter. The scaling exponent has a drastic effect on the optimal design of shell shapes. The observed characteristic shapes of natural shells are explained in a unified manner as a result of optimal utilization of shell material resources, while isometric growth in thickness leads to impossibly tight coiling. PMID:28186171

  2. Microbiological and Chemical Analysis of Land Snails Commercialised in Sicily

    PubMed Central

    Cicero, Antonello; Giangrosso, Giuseppe; Cammilleri, Gaetano; Macaluso, Andrea; Currò, Vittoria; Galuppo, Lucia; Vargetto, Daniela; Vicari, Domenico

    2015-01-01

    In this study 160 samples of snails belonging to the species Helix aspersa maxima and Helix aspersa muller were examined for chemical and microbiological analysis. Samples came from Greece and Poland. Results showed mean concentration of cadmium (0.35±0.036 mg/kg) and lead (0.05±0.013 mg/kg) much higher than the limit of detection. Mercury levels in both species were not detected. Microbiological analysis revealed the absence of Salmonella spp. and Clostridium spp. in both examined species. E. coli and K. oxytoca were observed in Helix aspersa maxima and Helix aspersa muller. Furthermore, one case of fungi positivity in samples of Helix aspersa muller was found. The reported investigations highlight the need to create and adopt a reference legislation to protect the health of consumers. PMID:27800385

  3. Toxins from cone snails: properties, applications and biotechnological production.

    PubMed

    Becker, Stefan; Terlau, Heinrich

    2008-05-01

    Cone snails are marine predators that use venoms to immobilize their prey. The venoms of these mollusks contain a cocktail of peptides that mainly target different voltage- and ligand-gated ion channels. Typically, conopeptides consist of ten to 30 amino acids but conopeptides with more than 60 amino acids have also been described. Due to their extraordinary pharmacological properties, conopeptides gained increasing interest in recent years. There are several conopeptides used in clinical trials and one peptide has received approval for the treatment of pain. Accordingly, there is an increasing need for the production of these peptides. So far, most individual conopeptides are synthesized using solid phase peptide synthesis. Here, we describe that at least some of these peptides can be obtained using prokaryotic or eukaryotic expression systems. This opens the possibility for biotechnological production of also larger amounts of long chain conopeptides for the use of these peptides in research and medical applications.

  4. Trematode parasites infect or die in snail hosts

    PubMed Central

    King, Kayla C.; Jokela, Jukka; Lively, Curtis M.

    2011-01-01

    The Red Queen hypothesis is based on the assumption that parasites must genetically match their hosts to infect them successfully. If the parasites fail, they are assumed to be killed by the host's immune system. Here, we tested this using sympatric (mostly susceptible) and allopatric (mostly resistant) populations of a freshwater snail and its trematode parasite. We determined whether parasites which do not infect are either killed or passed through the host's digestive tract and remain infectious. Our results show that parasites do not get a second chance: they either infect or are killed by the host. The results suggest strong selection against parasites that are not adapted to local host genotypes. PMID:20961880

  5. Diversity increases biomass production for trematode parasites in snails

    USGS Publications Warehouse

    Hechinger, Ryan F.; Lafferty, Kevin D.; Kuris, Armand M.

    2008-01-01

    Increasing species diversity typically increases biomass in experimental assemblages. But there is uncertainty concerning the mechanisms of diversity effects and whether experimental findings are relevant to ecological process in nature. Hosts for parasites provide natural, discrete replicates of parasite assemblages. We considered how diversity affects standing-stock biomass for a highly interactive parasite guild: trematode parasitic castrators in snails. In 185 naturally occurring habitat replicates (individual hosts), diverse parasite assemblages had greater biomass than single-species assemblages, including those of their most productive species. Additionally, positive diversity effects strengthened as species segregated along a secondary niche axis (space). The most subordinate species—also the most productive when alone—altered the general positive effect, and was associated with negative diversity effects on biomass. These findings, on a previously unstudied consumer class, extend previous research to illustrate that functional diversity and species identity may generally both explain how diversity influences biomass production in natural assemblages of competing species.

  6. Disulfiram inhibits TGF-β-induced epithelial-mesenchymal transition and stem-like features in breast cancer via ERK/NF-κB/Snail pathway

    PubMed Central

    Chang, Chan; Zhu, Fang; Xiao, Yin; Li, Qiuhui; Zhang, Tao; Zhang, Liling

    2015-01-01

    Disulfiram (DSF), an anti-alcoholism drug, has been reported as an inhibitor of NF-κB. NF-κB is involved in epithelial-mesenchymal transition (EMT) and self-renewal of breast cancer stem cells (CSCs). In this study, we treated MCF-7 and MDA-MB-231 breast cancer cells with TGF-β to induce EMT and cancer stem-like features and studied whether DSF can reverse this process. We found that DSF inhibited TGF-β induced EMT in breast cancer cells in a dose-dependent manner. Also, DSF inhibited EMT-associated stem-like features, migration and invasion of tumor cells as well as tumor growth in xenograft model. The activation of NF-κB was linked with EMT and stem-like cells. We conclude that DSF can suppress NF-κB activity and downregulate ERK/NF-κB/Snail pathway, leading to reverse EMT and stem-like features. Our data suggest that DSF inhibits EMT and stem-like properties in breast cancer cells associated with inhibition of the ERK/NF-κB/Snail pathway. PMID:26517513

  7. 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

  8. 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.

  9. Deterministic assembly of land snail communities according to species size and diet.

    PubMed

    Schamp, Brandon; Horsák, Michal; Hájek, Michal

    2010-07-01

    1. We investigated whether coexisting snail species in 145 treeless fen communities in the Western Carpathian Mountains differed more in size and diet than would be expected by chance, as predicted for traits commonly associated with competition and differential resource acquisition under limiting similarity theory. 2. Contrary to expectations, coexisting snail species were no more different in body size than expected by chance under a null model. However, variation in body size played a significant role in structuring snail communities: coexisting snail species were significantly more similar with respect to body size. 3. We developed two new test statistics to expand our investigation of limiting similarity to include diet, a nominal trait. We tested whether communities of snails were characterized by a greater richness of diet, and whether different diets were represented more or less evenly within communities. Communities of snails were significantly less evenly distributed than expected by chance, with detritivores being over-represented relative to predatory strategies. 4. We also examined the effect of water pH and conductivity, herbaceous cover, and bryophyte and vascular plant richness, on these trends by examining how the effect size of our tests varied across these gradients. Convergence in species size increased with increasing habitat pH. Specifically, smaller snail species were over-represented in fen communities in general, and this effect was accentuated in increasingly calcareous fens. 5. Theory predicts that traits related strongly to environmental conditions are more likely to be convergent. Our findings support this suggestion, as small snail species have an advantage in tolerating freezing conditions over winter when refuges are limited. 6. These results add to the growing body of literature demonstrating that variation in body size and diet play a strong role in structuring communities, although frequently in ways not predicted by limiting

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

    USGS Publications Warehouse

    Lorda, Julio; Lafferty, Kevin D.

    2012-01-01

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

  11. Cytokines and mother sporocysts in susceptible and resistant Bulinus truncatus snails infected with Schistosoma haematobium.

    PubMed

    El-Din, Abdel Hakim Saad; Gawish, Fathiya Ali; Abu El Einin, Hanaa Mohamed; Mansour, Shereen Mahfouz

    2014-08-01

    The presence of immunoreactive interleukin (IL-2), interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) in addition to the citation of mother sporscytes in cephalopodal musculature in the susceptible and resistance Bulinus truncatus the specific intermediate host for the trematode Schistosoma haematobium were investigated,. Using ELISA tests, Results indicated that the concentration of IL-2-like activity in the susceptible and resistant snails decreased significantly after infection then persisted at low levels until the 4th week post exposure (WPE) in susceptible snails, while in resistant snails elevated during the second WPE, and returned to initial level at 3 and 4 WPE. Susceptible snails had low detectable levels of TNF-α and INF-γ like-activity after infection. However, the resistant snails had significant low levels of TNF-α and INF-γ like-activity from 3 WPE until the 4th WPE without any sign of normalization. Histological sections in the head- foot region of susceptible and resistance B. truncatus infected with S. haematobium, mother sporocysts exists from 1 to 7(day post exposure) DPE, in the susceptible snail the mother sporocysts were found as single, multiple and mature types. No mother sporocysts were appear in the lip and mantle of the snail on 2, 5, 7 DPE and on 1-3, 6 DPE respectively. In the resistant snails few mother sporocysts were found in the lip, mantle and tentacles. The results showed that schistosome-resistant Bulinus can be an alternative strategy for the control of schistosomiasis.

  12. Effects of exposure of aquatic snails to sublethal concentrations of waste drilling fluid.

    PubMed

    Ekundayo, J A; Benka-Coker, M O

    1994-05-01

    Static bioassays were carried out using two aquatic snails (Pilia sp. and Lanistes sp.) as test organisms in soft natural dilution water, with waste drilling fluid as the test material, at 28±2°C. Comparison of results for the control and different concentrations of the waste drilling fluid were made by means of the F-statistic method. The waste drilling fluid was practically non-toxic to the two aquatic snails.

  13. Dysregulated expression of Snail and E-cadherin correlates with gastrointestinal stromal tumor metastasis.

    PubMed

    Liu, Sheng; Liao, Guoqing; Ding, Jie; Ye, Ke; Zhang, Yi; Zeng, Liang; Chen, Senlin

    2014-09-01

    Snail, a zinc finger structure transcription inhibitory factor, has been reported to play an important role in the metastatic progression of several types of cancer. The aim of the study was to identify potential biomarkers for metastasis in gastrointestinal stromal tumors (GISTs) by examining the expression levels of Snail, E-cadherin, and Vimentin in GISTs and investigate their clinical significance. The protein expression of Snail, E-cadherin, and Vimentin in 74 GIST specimens was detected by immunohistochemical analysis, and the correlation between expression levels and clinicopathological data was analyzed. Snail, E-cadherin, and Vimentin were positively expressed in 51.4% (38/74), 32.4% (24/74), and 68.9% (51/74) of GIST tissue samples, respectively. Snail protein expression was significantly higher in GISTs with distant metastasis compared with GISTs without distant metastasis (P<0.05). E-cadherin expression level was significantly lower in cases of GIST with distant metastasis compared with those without distant metastasis (P<0.05), whereas the expression level of Vimentin did not significantly change according to clinical and pathological characteristics (all P>0.05). Snail expression was significantly negatively correlated with E-cadherin expression (r's=-0.276, P=0.017) but not with Vimentin expression (r's=0.041, P=0.728) in GISTs. High Snail expression and low E-cadherin expression were significantly correlated with metastasis in GISTs, and Snail, because of positive correlation, is potentially a biomarker of GIST with distant metastasis.

  14. 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.

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

    PubMed Central

    2011-01-01

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

  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. 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.

  18. Unraveling the peptidome of the South African cone snails Conus pictus and Conus natalis.

    PubMed

    Peigneur, Steve; Van Der Haegen, Annelies; Möller, Carolina; Waelkens, Etienne; Diego-García, Elia; Marí, Frank; Naudé, Ryno; Tytgat, Jan

    2013-03-01

    Venoms from cone snails (genus Conus) can be seen as an untapped cocktail of biologically active compounds, being increasingly recognized as an emerging source of peptide-based therapeutics. Cone snails are considered to be specialized predators that have evolved the most sophisticated peptide chemistry and neuropharmacology system for their own biological purposes by producing venoms which contains a structural and functional diversity of neurotoxins. These neurotoxins or conotoxins are often small cysteine-rich peptides which have shown to be highly selective ligands for a wide range of ion channels and receptors. Local habitat conditions have constituted barriers preventing the spreading of Conus species occurring along the coast of South Africa. Due to their scarceness, these species remain, therefore, extremely poorly studied. In this work, the venoms of two South African cone snails, Conus pictus, a vermivorous snail and Conus natalis, a molluscivorous snail, have been characterized in depth. In total, 26 novel peptides were identified. Comparing the venoms of both snails, interesting differences were observed regarding venom composition and molecular characteristics of these components.

  19. Spatial distribution of Biomphalaria spp., the intermediate host snails of Schistosoma mansoni, in Brazil.

    PubMed

    Scholte, Ronaldo G C; Carvalho, Omar S; Malone, John B; Utzinger, Jürg; Vounatsou, Penelope

    2012-09-01

    Schistosomiasis mansoni remains an important parasitic disease of man, endemic in large parts of sub-Saharan Africa, the Middle East, South America and the Caribbean. The aetiological agent is the trematode Schistosoma mansoni, whereas aquatic snails of the genus Biomphalaria act as intermediate hosts in the parasite life cycle. In Brazil, the distribution of Biomphalaria spp. is closely associated with the occurrence of schistosomiasis. The purpose of this study was to map and predict the spatial distribution of the intermediate host snails of S. mansoni across Brazil. We assembled snail "presenceonly" data and used a maximum entropy approach, along with climatic and environmental variables to produce predictive risk maps. We identified a series of risk factors that govern the distribution of Biomphalaria snails. We find that high-risk areas for B. glabrata are concentrated in the regions of Northeast and Southeast and the northern part of the South region. B. straminea are found in the Northeast and Southeast regions, and B. tenagophila are concentrated in the Southeast and South regions. Our findings confirm that the presence of the intermediate host snails is correlated with the occurrence of schistosomiasis mansoni. The generated risk maps of intermediate host snails might assist the national control programme for spatial targeting of control interventions and to ultimately move towards schistosomiasis elimination in Brazil.

  20. 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

  1. Seasonal variation in abiotic factors and ferulic acid toxicity in snail-attractant pellets against the intermediate host snail Lymnaea acuminata.

    PubMed

    Agrahari, P; Singh, D K

    2013-11-01

    Laboratory evaluation was made to access the seasonal variations in abiotic environmental factors temperature, pH, dissolved oxygen, carbon dioxide, electrical conductivity and ferulic acid toxicity in snail-attractant pellets (SAP) against the intermediate host snail Lymnaea acuminata in each month of the years 2010 and 2011. On the basis of a 24-h toxicity assay, it was noted that lethal concentration values of 4.03, 3.73% and 4.45% in SAP containing starch and 4.16, 4.23% and 4.29% in SAP containing proline during the months of May, June and September, respectively, were most effective in killing the snails, while SAP containing starch/proline + ferulic acid was least effective in the month of January/February (24-h lethal concentration value was 7.67%/7.63% in SAP). There was a significant positive correlation between lethal concentration value of ferulic acid containing SAP and levels of dissolved O2 /pH of water in corresponding months. On the contrary, a negative correlation was observed between lethal concentration value and dissolved CO2 /temperature of test water in the same months. To ascertain that such a relationship between toxicity and abiotic factors is not co-incidental, the nervous tissue of treated (40% and 80% of 24-h lethal concentration value) and control group of snails was assayed for the activity of acetylcholinesterase (AChE) in each of the 12 months of the same year. There was a maximum inhibition of 58.43% of AChE, in snails exposed to 80% of the 24-h lethal concentration value of ferulic acid + starch in the month of May. This work shows conclusively that the best time to control snail population with SAP containing ferulic acid is during the months of May, June and September.

  2. Research on Dynamic Monitoring (1990-2010) of Schistosomiasis Vector-Snail at Xinmin Beach, Gaoyou Lake, Jiangsu Province, China

    NASA Astrophysics Data System (ADS)

    Liu, Zhaoyan; Li, Chuanrong; Tang, Lingli; Zhou, Xiaonong; Ma, Lingling

    2014-11-01

    Schistosomiasis is a parasitic disease that menaces human health. In terms of impact, this disease is second only to malaria as the most devastating parasitic disease. Oncomelania hupensis (snail) is the unique intermediate host of schistosoma, so monitoring and controlling of the number of snail is key to reduce the risk of schistosomiasis transmission. Remote sensing technology can real-timely access the large-scale environmental factors related to snail breeding and reproduction, and can also provide the efficient information to determine the location, area, and spread tendency of snail. Based on the T-S (Takagi-Sugeno) fuzzy information theory, a quantitative remote sensing monitoring model of snail has been developed in previous wok. In a case study, this paper will take Xinmin beach, Gaoyou Lake as new research area, carry out 20 years (1990 - 2010) dynamic monitoring, to further validate the effectiveness of the T-S Fuzzy RS snail monitoring model.

  3. Research on Dynamic Monitoring (1990-2010)of Schistosomiasis Vector- Snail at Xinmin Beach, Gaoyou Lake, Jiangsu Province, China

    NASA Astrophysics Data System (ADS)

    Liu, Zhaoyan; Li, Chuanrong; Tang, Lingli; Zhou, Xiaonong; Ma, Lingling

    2014-11-01

    Schistosomiasis is a parasitic disease that menaces human health. In terms of impact, this disease is second only to malaria as the most devastating parasitic disease. Oncomelania hupensis (snail) is the unique intermediate host of schistosoma, so monitoring and controlling of the number of snail is key to reduce the risk of schistosomiasis transmission. Remote sensing technology can real-timely access the large-scale environmental factors related to snail breeding and reproduction, and can also provide the efficient information to determine the location, area, and spread tendency of snail. Based on the T-S (Takagi-Sugeno) fuzzy information theory, a quantitative remote sensing monitoring model of snail has been developed in previous wok. In a case study, this paper will take Xinmin beach, Gaoyou Lake as new research area, carry out 20 years (1990 - 2010) dynamic monitoring, to further validate the effectiveness of the T-S Fuzzy RS snail monitoring model.

  4. The biocide tributyltin reduces the accumulation of testosterone as fatty acid esters in the mud snail (Ilyanassa obsoleta).

    PubMed Central

    Gooding, Meredith P; Wilson, Vickie S; Folmar, Leroy C; Marcovich, Dragoslav T; LeBlanc, Gerald A

    2003-01-01

    Imposex, the development of male sex characteristics by female gonochoristic snails, has been documented globally and is causally associated with exposure to the ubiquitous environmental contaminant tributyltin (TBT). Elevated testosterone levels in snails also are associated with TBT, and direct exposure to testosterone has been shown to cause imposex. We discovered previously that the mud snail (Ilyanassa obsoleta)biotransforms and retains excess testosterone primarily as fatty acid esters. The purpose of this study was to determine whether TBT interferes with the esterification of testosterone, resulting in the elevated free (unesterified) testosterone levels associated with imposex. Exposure of snails to environmentally relevant concentrations of TBT (> or = 1.0 ng/L as tin) significantly increased the incidence of imposex. Total (free + esterified) testosterone levels in snails were not altered by TBT; however, free testosterone levels increased with increasing exposure concentration of TBT. TBT-exposed snails were given [14C

  5. Enhancement of cancer stem-like and epithelial−mesenchymal transdifferentiation property in oral epithelial cells with long-term nicotine exposure: Reversal by targeting SNAIL

    SciTech Connect

    Yu, Cheng-Chia; Chang, Yu-Chao

    2013-02-01

    Cigarette smoking is one of the major risk factors in the development and further progression of tumorigenesis, including oral squamous cell carcinoma (OSCC). Recent studies suggest that interplay cancer stem-like cells (CSCs) and epithelial−mesenchymal transdifferentiation (EMT) properties are responsible for the tumor maintenance and metastasis in OSCC. The aim of the present study was to investigate the effects of long-term exposure with nicotine, a major component in cigarette, on CSCs and EMT characteristics. The possible reversal regulators were further explored in nicotine-induced CSCs and EMT properties in human oral epithelial (OE) cells. Long-term exposure with nicotine was demonstrated to up-regulate ALDH1 population in normal gingival and primary OSCC OE cells dose-dependently. Moreover, long-term nicotine treatment was found to enhance the self-renewal sphere-forming ability and stemness gene signatures expression and EMT regulators in OE cells. The migration/cell invasiveness/anchorage independent growth and in vivo tumor growth by nude mice xenotransplantation assay was enhanced in long-term nicotine-stimulated OE cells. Knockdown of Snail in long-term nicotine-treated OE cells was found to reduce their CSCs properties. Therapeutic delivery of Si-Snail significantly blocked the xenograft tumorigenesis of long-term nicotine-treated OSCC cells and largely significantly improved the recipient survival. The present study demonstrated that the enrichment of CSCs coupled EMT property in oral epithelial cells induced by nicotine is critical for the development of OSCC tumorigenesis. Targeting Snail might offer a new strategy for the treatment of OSCC patients with smoking habit. -- Highlights: ► Sustained nicotine treatment induced CSCs properties of oral epithelial cells. ► Long-term nicotine treatment enhance EMT properties of oral epithelial cells. ► Long-term nicotine exposure increased tumorigenicity of oral epithelial cells. ► Si-Snail

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

    PubMed

    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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

    Foote, B. A.

    2005-05-01

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

  9. 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

  10. 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.

  11. Hepatic stellate cell promoted hepatoma cell invasion via the HGF/c-Met signaling pathway regulated by p53.

    PubMed

    Liu, Wen-Ting; Jing, Ying-Ying; Yu, Guo-feng; Chen, Hong; Han, Zhi-peng; Yu, Dan-Dan; Fan, Qing-Min; Ye, Fei; Li, Rong; Gao, Lu; Zhao, Qiu-Dong; Wu, Meng-Chao; Wei, Li-Xin

    2016-01-01

    The biological behaviors of hepatocellular carcinoma (HCC) are complex mainly due to heterogeneity of progressive genetic and epigenetic mutations as well as tumor environment. Hepatocyte growth factor (HGF)/c-Met signaling pathway is regarded to be a prototypical example for stromal-epithelial interactions during developmental morphogenesis, wound healing, organ regeneration and cancer progression. And p53 plays as an important regulator of Met-dependent cell motility and invasion. Present study showed that 2 HCC cell lines, Hep3B and HepG2, displayed different invasive capacity when treated with HGF which was secreted by hepatic stellate cells (HSCs). We found that HGF promoted Hep3B cells invasion and migration as well as epithelial-mesenchymal transition (EMT) occurrence because Hep3B was p53 deficient, which leaded to the c-Met over-expression. Then we found that HGF/c-Met promoted Hep3B cells invasion and migration by upregulating Snail expression. In conclusion, HGF/c-Met signaling is enhanced by loss of p53 expression, resulting in increased ability of invasion and migration by upregulating the expression of Snail.

  12. 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

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

    PubMed

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

    2012-01-15

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

  14. Distribution of trematodes in snails in ponds at integrated small-scale aquaculture farms.

    PubMed

    Boerlage, Annette S; Graat, Elisabeth A M; Verreth, Johan A; de Jong, Mart C M

    2013-03-01

    In integrated small-scale aquaculture farming, animal and human excreta maybe used as fish feed and pond fertilizer, thereby enhancing transmission of fish-borne zoonotic trematodes (FZTs) from final hosts, like humans, pigs and chickens, to snails. Areas within a pond could vary in trematode egg-load due to the immediate bordering land, and this might provide implications for control of these trematodes or sampling in field studies measuring FZT prevalence in snails. We therefore estimated the effect of bordering land use on prevalence and FZT burden in snails in different areas within small-scale aquaculture ponds. Nine sampling areas within a pond were assigned in six ponds. For each sampling area, about 120 Melanoides tuberculata snails were collected. Based on land use bordering a sampling area, these were categorized in 5 risk-categories: low-risk (road, rice planted in pond, agriculture, or middle of pond), human access point to pond, livestock sty (pigs or poultry), both human access point and livestock sty, and water connection to canal. In total, 5392 snails were collected. Percentages of snails with parapleurolophocercous cercariae varied between 6% in areas categorized as low-risk and areas with livestock sty only to 15% in areas with both human access point and livestock sty; only this 15% was significantly different from the prevalence in the low-risk category. Percentages of snails with xiphidio cercariae did not differ between risk-categories and varied between 5% and 10%. Mean snail size was 15.2mm, and was significantly associated with both the probability of infection as well as parasite burden. Very small differences in parasite burden were found at different land use areas; the maximum difference was about 11 cercariae. This study demonstrated only small differences between areas surrounding a pond on risk of snails to be infected with fish-borne trematodes within different pond areas. In field studies on FZTs in M. tuberculata snails in ponds

  15. Attacking invasive grasses

    USGS Publications Warehouse

    Keeley, Jon E.

    2015-01-01

    In grasslands fire may play a role in the plant invasion process, both by creating disturbances that potentially favour non-native invasions and as a possible tool for controlling alien invasions. Havill et al. (Applied Vegetation Science, 18, 2015, this issue) determine how native and non-native species respond to different fire regimes as a first step in understanding the potential control of invasive grasses.

  16. Chlorophyllin Bait Formulation and Exposure to Different Spectrum of Visible Light on the Reproduction of Infected/Uninfected Snail Lymnaea acuminata

    PubMed Central

    Kumar, Navneet; Singh, D. K.; Singh, Vinay Kumar

    2016-01-01

    Fasciolosis is a waterborne disease, caused by Fasciola species. Snail Lymnaea acuminata is an intermediate host of these flukes. Control of snail population is major tool in reducing the incidences. Variation in light intensity and wavelength caused significant changes in reproduction pattern of snails. Maximum fecundity was noted with bait containing carbohydrate (starch, 468 ± 0.10/20 snails) or amino acid (serine, 319 ± 0.29/20 snails) as attractant. Sublethal feeding of chlorophyllin bait with starch or serine attractant to infected and uninfected snails caused significant reduction in fecundity, hatchability, and survivability. These significant changes are observed in snails exposed to different spectral band of visible light and sunlight. Maximum fecundity of 536 ± 2.0 and minimum of 89.3 ± 0.4 were noted in snails not fed with bait and exposed to sunlight and red spectral band, respectively. There was complete arrest in the fecundity of infected and uninfected snails and no survivability of uninfected snails after 48 h feeding with bait containing chlorophyllin + attractant. Minimum hatchability (9.25 ± 0.5) was noted in red light exposed, chlorophyllin + starch fed infected snails and hatching period of bait fed snails was prolonged. Conclusively, chlorophyllin bait and red light reduce reproduction capacity in snails. PMID:26925296

  17. Chlorophyllin Bait Formulation and Exposure to Different Spectrum of Visible Light on the Reproduction of Infected/Uninfected Snail Lymnaea acuminata.

    PubMed

    Kumar, Navneet; Singh, D K; Singh, Vinay Kumar

    2016-01-01

    Fasciolosis is a waterborne disease, caused by Fasciola species. Snail Lymnaea acuminata is an intermediate host of these flukes. Control of snail population is major tool in reducing the incidences. Variation in light intensity and wavelength caused significant changes in reproduction pattern of snails. Maximum fecundity was noted with bait containing carbohydrate (starch, 468 ± 0.10/20 snails) or amino acid (serine, 319 ± 0.29/20 snails) as attractant. Sublethal feeding of chlorophyllin bait with starch or serine attractant to infected and uninfected snails caused significant reduction in fecundity, hatchability, and survivability. These significant changes are observed in snails exposed to different spectral band of visible light and sunlight. Maximum fecundity of 536 ± 2.0 and minimum of 89.3 ± 0.4 were noted in snails not fed with bait and exposed to sunlight and red spectral band, respectively. There was complete arrest in the fecundity of infected and uninfected snails and no survivability of uninfected snails after 48 h feeding with bait containing chlorophyllin + attractant. Minimum hatchability (9.25 ± 0.5) was noted in red light exposed, chlorophyllin + starch fed infected snails and hatching period of bait fed snails was prolonged. Conclusively, chlorophyllin bait and red light reduce reproduction capacity in snails.

  18. Invasive species in agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural production of food, feed, fiber or fuel is a local human activity with global ecological impacts, including the potential to foster invasions. Agriculture plays an unusual role in biological invasions, in that it is both a source of non-indigenous invasive species (NIS) and especially s...

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

    PubMed

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

    2011-12-01

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

  20. Increased SNAIL expression and low syndecan levels are associated with high Gleason grade in prostate cancer

    PubMed Central

    POBLETE, CRISTIAN E.; FULLA, JUAN; GALLARDO, MARCELA; MUÑOZ, VALENTINA; CASTELLÓN, ENRIQUE A.; GALLEGOS, IVAN; CONTRERAS, HECTOR R.

    2014-01-01

    Prostate cancer (PC) is a leading male oncologic malignancy wideworld. During malignant transformation, normal epithelial cells undergo genetic and morphological changes known as epithelial-mesenchymal transition (EMT). Several regulatory genes and specific marker proteins are involved in PC EMT. Recently, syndecans have been associated with malignancy grade and Gleason score in PC. Considering that SNAIL is mainly a gene repressor increased in PC and that syndecan promoters have putative binding sites for this repressor, we propose that SNAIL might regulate syndecan expression during PC EMT. The aim of this study was to analyze immunochemically the expression of SNAIL, syndecans 1 and 2 and other EMT markers in a tissue microarray (TMA) of PC samples and PC cell lines. The TMAs included PC samples of different Gleason grade and benign prostatic hyperplasia (BPH) samples, as non-malignant controls. PC3 and LNCaP cell lines were used as models of PC representing different tumorigenic capacities. Semi-quantitative immunohistochemistry was performed on TMAs and fluorescence immunocytochemistry and western blot analysis were conducted on cell cultures. Results show that SNAIL exhibits increased expression in high Gleason specimens compared to low histological grade and BPH samples. Accordingly, PC3 cells show higher SNAIL expression levels compared to LNCaP cells. Conversely, syndecan 1, similarly to E-cadherin (a known marker of EMT), shows a decreased expression in high Gleason grades samples and PC3 cells. Interestingly, syndecan 2 shows no changes associated to histological grade. It is concluded that increased SNAIL levels in advanced PC are associated with low expression of syndecan 1. The mechanism by which SNAIL regulates the expression of syndecan 1 remains to be investigated. PMID:24424718

  1. 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.

  2. Thermal tolerance and climate warming sensitivity in tropical snails.

    PubMed

    Marshall, David J; Rezende, Enrico L; Baharuddin, Nursalwa; Choi, Francis; Helmuth, Brian

    2015-12-01

    Tropical ectotherms are predicted to be especially vulnerable to climate change because their thermal tolerance limits generally lie close to current maximum air temperatures. This prediction derives primarily from studies on insects and lizards and remains untested for other taxa with contrasting ecologies. We studied the HCT (heat coma temperatures) and ULT (upper lethal temperatures) of 40 species of tropical eulittoral snails (Littorinidae and Neritidae) inhabiting exposed rocky shores and shaded mangrove forests in Oceania, Africa, Asia and North America. We also estimated extremes in animal body temperature at each site using a simple heat budget model and historical (20 years) air temperature and solar radiation data. Phylogenetic analyses suggest that HCT and ULT exhibit limited adaptive variation across habitats (mangroves vs. rocky shores) or geographic locations despite their contrasting thermal regimes. Instead, the elevated heat tolerance of these species (HCT = 44.5 ± 1.8°C and ULT = 52.1 ± 2.2°C) seems to reflect the extreme temperature variability of intertidal systems. Sensitivity to climate warming, which was quantified as the difference between HCT or ULT and maximum body temperature, differed greatly between snails from sunny (rocky shore; Thermal Safety Margin, TSM = -14.8 ± 3.3°C and -6.2 ± 4.4°C for HCT and ULT, respectively) and shaded (mangrove) habitats (TSM = 5.1 ± 3.6°C and 12.5 ± 3.6°C). Negative TSMs in rocky shore animals suggest that mortality is likely ameliorated during extreme climatic events by behavioral thermoregulation. Given the low variability in heat tolerance across species, habitat and geographic location account for most of the variation in TSM and may adequately predict the vulnerability to climate change. These findings caution against generalizations on the impact of global warming across ectothermic taxa and highlight how the consideration of nonmodel animals, ecological transitions

  3. 14-3-3ζ and aPKC-ι synergistically facilitate epithelial-mesenchymal transition of cholangiocarcinoma via GSK-3β/snail signaling pathway

    PubMed Central

    He, Jun-chuang; Wang, Jian-ming; Schemmer, Peter; Ma, Chao-qun; Qian, Ya-wei; Yao, Wei; Zhang, Jian; Qi, Wei-peng; Fu, Yang; Feng, Wei; Yang, Tao

    2016-01-01

    Cholangiocarcinoma (CCA) invasion and metastasis are the primary causes of poor survival rates in patients. The epithelial-mesenchymal transition (EMT) is a crucial step in cancer invasion and metastasis. However, it is still unclear of the molecular mechanism. In this study, the expression of 14-3-3ζ and atypical protein kinase C-ι (aPKC-ι) was further detected in CCA tissues and cell lines. Meanwhile, we established the EMT model of CCA cells and investigated 14-3-3ζ and aPKC-ι co-regulatory effect on the EMT in vitro and in vivo. Further, we identified the downstream molecular glycogen synthase kinase 3 beta (GSK-3β)/Snail signalling pathway that contribute to regulating the EMT. Our data showed that the expression of 14-3-3ζ and aPKC-ι was synergistically increased in CCA tissues compared with adjacent noncancerous tissues and was intimately associated with differentiation and the tumour-node-metastasis (TNM) stage. Multivariate Cox regression analysis indicated that high 14-3-3ζ and aPKC-ι expression separately predicted a poor prognosis and were independent prognostic indicators in patients with CCA. The CO-IP experiment confirmed that the mutual binding relationship between 14-3-3ζ and aPKC-ι. Small interfering RNAs and siRNA rescue experiment demonstrated that 14-3-3ζ and aPKC-ι regulated each other. In addition, 14-3-3ζ and aPKC-ι pretreatment by si-RNA inhibit the phosphorylated GSK-3β and Snail expression during EMT. Meanwhile, silence of 14-3-3ζ or aPKC-ι suppressed CCA cells migration, metastasis and proliferation in vitro and in vivo. Our study demonstrates that 14-3-3ζ and aPKC-ι synergistically facilitate EMT of CCA via GSK-3β/Snail signalling pathway, and may be potential therapeutic target for CCA. PMID:27409422

  4. Metformin Inhibits Migration and Invasion of Cholangiocarcinoma Cells

    PubMed

    Trinh, Son Xuan; Nguyen, Huyen Thi Bich; Saimuang, Kween; Prachayasittikul, Virapong; Chan On, Waraporn

    2017-02-01

    Background: Metformin is an oral anti-diabetic agent that has been widely prescribed for treatment of type II diabetes. Anti-cancer properties of metformin have been revealed for numerous human malignancies including cholangiocarcinoma (CCA) with anti-proliferative effects in vitro. However, effects on CCA cell migration and invasion have not been fully investigated. The present study aimed to explore the inhibitory effects of metformin on motility, migration and invasion of the CCA cell line HuCCT1, and examine molecular mechanisms underlying metformin effects. Methods: HuCCT1 cells were exposed to increasing doses of metformin. Viability and growth of HuCCT1 cells were assessed by MTS and colony formation assays, respectively. Motility, migration and invasion of metformin-treated HuCCT1 cells were determined in vitro using wound healing, transwell migration and matrigel invasion assays. Expression of signaling molecules and epithelial-mesenchymal transition (EMT) markers was assessed by Western blotting. Results: It was observed that metformin significantly decreased HuCCT1 cell viability and colony formation. The agent also markedly reduced wound closure, migration and invasion of HuCCT1 cells. Furthermore, metformin exposure resulted in decreased STAT3 activation and down-regulation of anti-apoptotic protein Bcl-2 and Mcl-1 expression. In addition, it upregulated the expression of E-cadherin, while downregulating that of N-cadherin, Snail, and MMP-2. Conclusion: These results demonstrated inhibitory effects of metformin on CCA cell migration and invasion, possibly involving the STAT3 pathway and reversal of EMT markers expression. They further suggest that metformin may be useful for CCA management.

  5. Eradication of invasive Tamarix ramosissima along a desert stream increases native fish density

    USGS Publications Warehouse

    Kennedy, T.A.; Finlay, J.C.; Hobbie, S.E.

    2005-01-01

    Spring ecosystems of the western United States have high conservation value, particularly because of the highly endemic, and often endangered, fauna that they support. Refuges now protect these habitats from many of the human impacts that once threatened them, but invasive species often persist. Invasive saltcedar is ubiquitous along streams, rivers, and spring ecosystems of the western United States, yet the impact of saltcedar invasion on these ecosystems, or ecosystem response to its removal, have rarely been quantified. Along Jackrabbit Spring, a springbrook in Nevada that supports populations of two endangered fish (Ash Meadows pupfish and Ash Meadows speckled dace) as well as several exotic aquatic consumers, we quantified the response of aquatic consumers to largescale saltcedar removal and identified the mechanism underlying consumer response to the removal. Clearing saltcedar from the riparian zone increased densities of native pupfish and exotic screw snails, but decreased the density of exotic crayfish. Positive effects of saltcedar removal on pupfish and snails occurred because saltcedar heavily shades the stream, greatly reducing the availability of algae for herbivores. This was confirmed by analyses of potential organic matter sources and consumer 13C: pupfish and snails, along with native dace and exotic mosquitofish, relied heavily on algae-derived carbon and not saltcedar-derived carbon. By contrast, crayfish ??13C values mirrored algae ??13C during summer, but in winter indicated reliance on allochthonous saltcedar litter that dominated organic inputs in saltcedar reaches and on algae-derived carbon where saltcedar was absent. The seasonal use of saltcedar by crayfish likely explains its negative response to saltcedar removal. Clearing saltcedar effectively restored the springbrook of Jackrabbit Spring to the conditions characteristic of native vegetation sites. Given the high conservation value of spring ecosystems and the potential conservation

  6. Gemifloxacin, a fluoroquinolone antimicrobial drug, inhibits migration and invasion of human colon cancer cells.

    PubMed

    Kan, Jung-Yu; Hsu, Ya-Ling; Chen, Yen-Hsu; Chen, Tun-Chieh; Wang, Jaw-Yuan; Kuo, Po-Lin

    2013-01-01

    Gemifloxacin (GMF) is an orally administered broad-spectrum fluoroquinolone antimicrobial agent used to treat acute bacterial exacerbation of pneumonia and bronchitis. Although fluoroquinolone antibiotics have also been found to have anti-inflammatory and anticancer effects, studies on the effect of GMF on treating colon cancer have been relatively rare. To the best of our knowledge, this is the first report to describe the antimetastasis activities of GMF in colon cancer and the possible mechanisms involved. Results have shown that GMF inhibits the migration and invasion of colon cancer SW620 and LoVo cells and causes epithelial mesenchymal transition (EMT). In addition, GMF suppresses the activation of NF- κ B and cell migration and invasion induced by TNF- α and inhibits the TAK1/TAB2 interaction, resulting in decreased I κ B phosphorylation and NF- κ B nuclear translocation in SW620 cells. Furthermore, Snail, a critical transcriptional factor of EMT, was downregulated after GMF treatment. Overexpression of Snail by cDNA transfection significantly decreases the inhibitory effect of GMF on EMT and cell migration and invasion. In conclusion, GMF may be a novel anticancer agent for the treatment of metastasis in colon cancer.

  7. The maintenance of sex, clonal dynamics, and host-parasite coevolution in a mixed population of sexual and asexual snails.

    PubMed

    Jokela, Jukka; Dybdahl, Mark F; Lively, Curtis M

    2009-07-01

    Sexual populations should be vulnerable to invasion and replacement by ecologically similar asexual females because asexual lineages have higher per capita growth rates. However, as asexual genotypes become common, they may also become disproportionately infected by parasites. The Red Queen hypothesis postulates that high infection rates in the common asexual clones could periodically favor the genetically diverse sexual individuals and promote the short-term coexistence of sexual and asexual populations. Testing this idea requires comparison of competing sexual and asexual lineages that are attacked by natural parasites. To date no such data have been available. Here, we report on long-term dynamics and parasite coevolution in a "mixed" (sexual and asexual) population of snails (Potamopyrgus antipodarum). We found that, within 7-10 years, the most common clones were almost completely replaced by initially rare clones in two different habitats, while sexuals persisted throughout the study period. The common clones, which were initially more resistant to infection, also became more susceptible to infection by sympatric (but not allopatric) parasites over the course of the study. These results are consistent with the Red Queen hypothesis and show that the coevolutionary dynamics predicted by the theory may also favor sexual reproduction in natural populations.

  8. Influence of temperature acclimation and gut content on the supercooling ability of the land snail Cornu aspersum.

    PubMed

    Ansart, Armelle; Aulne, Pierre-Aymeric; Madec, Luc; Vernon, Philippe

    2008-05-01

    The invasive land snail Cornu aspersum possesses a low ability to supercool (c. -5 degrees C in winter) and survives only minimal ice formation in its body fluids, what may limit its expansion to colder environments. In the present study, we investigated the influence of acclimation and starvation on its supercooling ability. During eight weeks, individuals were maintained at 20 degrees C, fed or starved, or placed at 5 degrees C, directly or with progressive acclimation to cold and shorter photoperiod. Temperature of crystallisation of whole individual (Tc(I)) and hemolymph (Tc(H)), mass data and gut content were recorded every two weeks. Hemolymphatic glucose and glycerol were measured at the end of experiment and occurrence of intestinal ice-nucleating agents (INA) was researched. Acclimation had no effect on Tc(I) but stimulated purging of the gut. Starvation induced a slight decrease of Tc(I) whereas a high quantity of alimentary particles in the digestive tract limited the supercooling ability. Glucose and glycerol were not synthesized in cold conditions. Mean Tc(H) was low (c. -17 degrees C), some INA being present in hemolymph of fed animals. Intestinal content of starved individuals exhibited a mean Tc of c. -6 degrees C, decreasing to c. -12 degrees after heating, suggesting the presence of organic INA.

  9. Multi-tissue transcriptomics for construction of a comprehensive gene resource for the terrestrial snail Theba pisana

    PubMed Central

    Zhao, M.; Wang, T.; Adamson, K. J.; Storey, K. B.; Cummins, S. F.

    2016-01-01

    The land snail Theba pisana is native to the Mediterranean region but has become one of the most abundant invasive species worldwide. Here, we present three transcriptomes of this agriculture pest derived from three tissues: the central nervous system, hepatopancreas (digestive gland), and foot muscle. Sequencing of the three tissues produced 339,479,092 high quality reads and a global de novo assembly generated a total of 250,848 unique transcripts (unigenes). BLAST analysis mapped 52,590 unigenes to NCBI non-redundant protein databases and further functional analysis annotated 21,849 unigenes with gene ontology. We report that T. pisana transcripts have representatives in all functional classes and a comparison of differentially expressed transcripts amongst all three tissues demonstrates enormous differences in their potential metabolic activities. The genes differentially expressed include those with sequence similarity to those genes associated with multiple bacterial diseases and neurological diseases. To provide a valuable resource that will assist functional genomics study, we have implemented a user-friendly web interface, ThebaDB (http://thebadb.bioinfo-minzhao.org/). This online database allows for complex text queries, sequence searches, and data browsing by enriched functional terms and KEGG mapping. PMID:26852673

  10. Local adaptation along a continuous coastline: prey recruitment drives differentiation in a predatory snail.

    PubMed

    Sanford, Eric; Worth, David J

    2010-03-01

    Recent work demonstrates that nearshore oceanography can generate strong variation in the delivery of resources (nutrients and larvae) to benthic marine communities over spatial scales of tens to hundreds of kilometers. Moreover, variation in the strength of these bottom-up inputs is often spatially consistent, linked to regional centers of upwelling, coastal topography, and other stable features of the coastline. Whereas the ecological effects of these oceanographic links are increasingly clear, the possibility that these same bottom-up forces might impose spatially varying selection on consumers has not been addressed. Here, we test the hypothesis that a carnivorous snail (Nucella canaliculata) with direct development is locally adapted to persistent differences in prey recruitment within two adjacent oceanographic regions (northern California and Oregon, USA). Previous laboratory studies demonstrated that snails from Oregon rarely drilled the thick-shelled mussel Mytilus californianus, whereas snails from California readily drilled this prey. To test whether these differences reflect local adaptation, snails from two populations in each region were raised through two laboratory generations to minimize the potential influence of nongenetic effects. We then reciprocally outplanted these F2 generation snails to field enclosures at each of the four sites and monitored their growth for 11 months. Recruitment and availability of preferred prey (the acorn barnacle Balanus glandula and blue mussel Mytilus trossulus) at the experimental sites were 1-3 orders of magnitude lower in California than in Oregon. At the California sites, snails that originated from Oregon sources failed to drill larger M. californianus, encountered few alternative prey, and showed almost no growth. In contrast, snails from California drilled M. californianus and showed substantial growth. These results strongly suggest that the capacity of California snails to drill M. californianus allows

  11. Methamphetamine enhances memory of operantly conditioned respiratory behavior in the snail Lymnaea stagnalis.

    PubMed

    Kennedy, Colin D; Houmes, Stephen W; Wyrick, Katherine L; Kammerzell, Samuel M; Lukowiak, Ken; Sorg, Barbara A

    2010-06-15

    Amphetamines have been used as cognitive enhancers to promote learning and memory. Amphetamines are also drugs of abuse that may promote the initiation of strong memories that ultimately lead to addiction. To understand how methamphetamine (Meth) may be augmenting learning and memory, we chose a relatively simple system, the pond snail, Lymnaea stagnalis. We studied the effects of Meth exposure on the long-term memory (LTM), extinction and reinstatement of operantly conditioned aerial respiratory behavior in Lymnaea. We first determined doses of Meth that would acutely alter respiratory behavior. Next, we measured the impact of training snails in Meth solution or water (control group) using a training procedure that produces LTM (>6 h) in control conditions. Meth exposure impaired the expression of LTM 21 h after two training sessions, but this appeared to be a context-dependent effect only. However, snails exposed to 3.3 mumol l(-1) Meth during training had a decreased rate of extinction of the operantly conditioned memory. We then tested whether this decreased ability of snails to extinguish memory was due to enhanced LTM or impaired extinction of that memory. Snails were operantly conditioned in water and exposed to Meth 16 h after their last trial but 4-5 h prior to extinction. Meth produced an increase rather than a decrease in extinction rate. Thus, Meth impaired extinction only when snails were exposed to Meth during training. Last, we tested the effect of Meth on the ability to form LTM using a single training procedure that is suboptimal for LTM formation. Control snails did not demonstrate LTM, as expected, but pre-exposure of snails to 3.3 micromol l(-1) Meth 24 h prior to the single training session produced LTM 24 h later, indicating that Meth pre-exposure primed snails for LTM formation. Taken together, our studies suggest that LTM is strengthened by Meth such that extinction training is less effective. Lymnaea provides a simple and useful model

  12. Accelerated mutation accumulation in asexual lineages of a freshwater snail.

    PubMed

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

    2010-04-01

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

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

    PubMed Central

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

    2001-01-01

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

  14. Calcium-activated potassium conductance noise in snail neurons.

    PubMed

    Westerfield, M; Lux, H D

    1982-11-01

    Current fluctuations were measured in small, 3-6 micrometers-diameter patches of soma membrane in bursting neurons of the snail, Helix pomatia. The fluctuations dramatically increased in magnitude with depolarization of the membrane potential under voltage clamp conditions. Two components of conductance noise were identified in the power spectra calculated from the membrane currents. One component had a corner frequency which increased with depolarization. This component was blocked by intracellular injection of TEA and was relatively insensitive to extracellular calcium levels (as long as the total number of effective divalent cations remained constant). It was identified as fluctuations of the voltage-dependent component of delayed outward current. The second component of conductance noise had a corner frequency which decreased with depolarization. It was relatively unaffected by TEA injection and was reversibly blocked by substitution of extracellular calcium with magnesium, cobalt, or nickel. This second component of noise was identified as fluctuations of the calcium-dependent potassium current. The results suggest that the two components of delayed outward current are conducted through physically distinct channels.

  15. Myosin-dependent remodeling of adherens junctions protects junctions from Snail-dependent disassembly

    PubMed Central

    Weng, Mo

    2016-01-01

    Although Snail is essential for disassembly of adherens junctions during epithelial–mesenchymal transitions (EMTs), loss of adherens junctions in Drosophila melanogaster gastrula is delayed until mesoderm is internalized, despite the early expression of Snail in that primordium. By combining live imaging and quantitative image analysis, we track the behavior of E-cadherin–rich junction clusters, demonstrating that in the early stages of gastrulation most subapical clusters in mesoderm not only persist, but move apically and enhance in density and total intensity. All three phenomena depend on myosin II and are temporally correlated with the pulses of actomyosin accumulation that drive initial cell shape changes during gastrulation. When contractile myosin is absent, the normal Snail expression in mesoderm, or ectopic Snail expression in ectoderm, is sufficient to drive early disassembly of junctions. In both cases, junctional disassembly can be blocked by simultaneous induction of myosin contractility. Our findings provide in vivo evidence for mechanosensitivity of cell–cell junctions and imply that myosin-mediated tension can prevent Snail-driven EMT. PMID:26754645

  16. Coordinating associative and ecological accounts of learning in the garden snail Cornu aspersum.

    PubMed

    Loy, I; Álvarez, B; Strempler-Rubio, E C; Rodríguez, M

    2017-03-08

    Pavlovian conditioning of tentacle lowering in the snail, Cornu aspersum, as an instance of associative learning, has proven effective to show evidence of paradigmatic associative phenomena (e.g., blocking) explained by current models of conditioning. Nevertheless, the available literature questions the biological function of the conditioned response (i.e., tentacle lowering) in snails since no advantages in terms of food finding had been observed. Ecological accounts of learning claim that learning abilities contribute to the adaptation to the environmental demands, and there is experimental evidence supporting this in several species (e.g., grasshoppers, fish, or antlions). However, there is a lack of evidence in snails, which is surprising given that the conditioned response of tentacle lowering is a robust finding that fits in with several predictions of associative learning theory (e.g., blocking or conditioned inhibition). The goal of this manuscript was to test whether food detection is affected by prior experience with the food, distance, and conditioning. We found that prior experience with a food source is necessary for snails to locate the same food item; that the optimal distance to test for food detection is between 5 and 7cm and that snails seem to use different food searching strategies after conditioning depending on the stimuli that are present. The data provided constitute a small contribution to the vindication of a greater coordination between the fruitful research tool provided by the associative account of learning and the evolutionary vocation of the ecological approach of learning.

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

    PubMed Central

    Sunita, Kumari; Singh, D. K.

    2011-01-01

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

  18. Distinct Bacterial Microbiomes in Sexual and Asexual Potamopyrgus antipodarum, a New Zealand Freshwater Snail.

    PubMed

    Takacs-Vesbach, Cristina; King, Kayla; Van Horn, David; Larkin, Katelyn; Neiman, Maurine

    2016-01-01

    Different reproductive strategies and the transition to asexuality can be associated with microbial symbionts. Whether such a link exists within mollusks has never been evaluated. We took the first steps towards addressing this possibility by performing pyrosequencing of bacterial 16S rRNA genes associated with Potamopyrgus antipodarum, a New Zealand freshwater snail. A diverse set of 60 tissue collections from P. antipodarum that were genetically and geographically distinct and either obligately sexual or asexual were included, which allowed us to evaluate whether reproductive mode was associated with a particular bacterial community. 2624 unique operational taxonomic units (OTU, 97% DNA similarity) were detected, which were distributed across ~30 phyla. While alpha diversity metrics varied little among individual samples, significant differences in bacterial community composition and structure were detected between sexual and asexual snails, as well as among snails from different lakes and genetic backgrounds. The mean dissimilarity of the bacterial communities between the sexual and asexual P. antipodarum was 90%, largely driven by the presence of Rickettsiales in sexual snails and Rhodobacter in asexual snails. Our study suggests that there might be a link between reproductive mode and the bacterial microbiome of P. antipodarum, though a causal connection requires additional study.

  19. Formin Is Associated with Left-Right Asymmetry in the Pond Snail and the Frog

    PubMed Central

    Davison, Angus; McDowell, Gary S.; Holden, Jennifer M.; Johnson, Harriet F.; Koutsovoulos, Georgios D.; Liu, M. Maureen; Hulpiau, Paco; Van Roy, Frans; Wade, Christopher M.; Banerjee, Ruby; Yang, Fengtang; Chiba, Satoshi; Davey, John W.; Jackson, Daniel J.; Levin, Michael; Blaxter, Mark L.

    2016-01-01

    Summary While components of the pathway that establishes left-right asymmetry have been identified in diverse animals, from vertebrates to flies, it is striking that the genes involved in the first symmetry-breaking step remain wholly unknown in the most obviously chiral animals, the gastropod snails. Previously, research on snails was used to show that left-right signaling of Nodal, downstream of symmetry breaking, may be an ancestral feature of the Bilateria [1, 2]. Here, we report that a disabling mutation in one copy of a tandemly duplicated, diaphanous-related formin is perfectly associated with symmetry breaking in the pond snail. This is supported by the observation that an anti-formin drug treatment converts dextral snail embryos to a sinistral phenocopy, and in frogs, drug inhibition or overexpression by microinjection of formin has a chirality-randomizing effect in early (pre-cilia) embryos. Contrary to expectations based on existing models [3, 4, 5], we discovered asymmetric gene expression in 2- and 4-cell snail embryos, preceding morphological asymmetry. As the formin-actin filament has been shown to be part of an asymmetry-breaking switch in vitro [6, 7], together these results are consistent with the view that animals with diverse body plans may derive their asymmetries from the same intracellular chiral elements [8]. PMID:26923788

  20. 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, γ-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.

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

    PubMed

    Madsen, H; Hung, N M

    2014-12-01

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

  2. Genetic variation between Biomphalaria alexandrina snails susceptible and resistant to Schistosoma mansoni infection.

    PubMed

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

    2013-01-01

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

  3. 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.

  4. Development of the feline lungworms Aelurostrongylus abstrusus and Troglostrongylus brevior in Helix aspersa snails.

    PubMed

    Giannelli, Alessio; Ramos, Rafael Antonio Nascimento; Annoscia, Giada; Di Cesare, Angela; Colella, Vito; Brianti, Emanuele; Dantas-Torres, Filipe; Mutafchiev, Yasen; Otranto, Domenico

    2014-04-01

    Aelurostrongylus abstrusus (Strongylida, Angiostrongylidae) and Troglostrongylus brevior (Strongylida, Crenosomatidae) are regarded as important lungworm species of domestic felids, with the latter considered an emerging threat in the Mediterranean region. The present study aimed to assess their concurrent development in the mollusc Helix aspersa (Pulmonata, Helicidae). Thirty snails were infested with 100 first-stage larvae (L1) of A. abstrusus and T. brevior, isolated from a naturally infested kitten. Larval development was checked by digesting five specimens at 2, 6 and 11 days post infestation. Larvae retrieved were morphologically described and their identification was confirmed by specific PCR and sequencing. All H. aspersa snails were positive for A. abstrusus and T. brevior, whose larval stages were simultaneously detected at each time point. In addition, snails were exposed to outdoor conditions and examined after overwintering, testing positive up to 120 days post infestation. Data herein presented suggest that A. abstrusus and T. brevior develop in H. aspersa snails and may eventually co-infest cats. Data on the morphology of both parasitic species in H. aspersa provide additional information on their development and identification, to better understand the population dynamics of these lungworms in receptive snails and paratenic hosts.

  5. 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

    2015-05-28

    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.

  6. Do ice nucleating agents limit the supercooling ability of the land snail Cornu aspersum?

    PubMed

    Ansart, A; Nicolai, A; Vernon, P; Madec, L

    2010-01-01

    The supercooling ability of adults and eggs of the partially freezing tolerant land snail Cornu aspersum remains limited to high subzero temperatures (ca. -5 degree C) whatever the conditions, suggesting the presence of ice nucleating agents (INAs). In this study, we investigated the nucleation activity of the digestive tract of adult snails, eggs and their direct environment: food, faeces and soil. The mucous ribbon always present in the distal intestine of adults exhibited a heat-sensitive (i.e. organic) nucleation activity, close to that of the entire snails during dormant states (aestivation and hibernation). However, a microbial nature of these INAs could not be established in inactive snails. The food provided to active snails contained ice nucleating bacteria, which followed the digestive tract to be found in the intestine and in the faeces, but with a decreasing concentration along the transit. Eggshells also presented a heat-sensitive nucleation activity, which could be related to its structure. Moreover, eggs are laid directly in the soil which contained both organic and mineral INAs. This study is the first to demonstrate the implication of organic INAs in the cold hardiness of a terrestrial gastropod.

  7. Asymmetry of mandibular dentition is associated with dietary specialization in snail-eating snakes

    PubMed Central

    2017-01-01

    Background In vertebrates, the left-and-right pairs of homologous organs are generally present in equal numbers. A remarkable exception is snail-eating snakes in the family Pareidae: almost all the pareid snakes have much more teeth on the right mandible than on the left for functional specialization in feeding on the dextral majority of land snails. Because the only exceptional species with symmetric dentition has been regarded as a slug-eater, the extent of dietary specialization on slugs could shape the degree of the lateral asymmetry of mandibular dentition (dentition asymmetry) even among snail eaters. Methods To test this, I compared the morphology and behavior of two sympatric species of Taiwanese snail-eating snakes, Pareas atayal and P. formosensis. Results Specimens collected in the same locality showed that the dentition asymmetry of P. formosensis was significantly smaller than that of P. atayal. Congruent to its weak asymmetry, P. formosensis showed a strong preference of slugs to snails in the feeding experiment. Discussion The dietary specialization of P. formosensis on slugs would contribute to niche partitioning from the sympatric congener P. atayal. This study suggests that the diverse variation in the dentition asymmetry of pareid snakes is the result of their dietary specialization and divergence. PMID:28265502

  8. Distinct Bacterial Microbiomes in Sexual and Asexual Potamopyrgus antipodarum, a New Zealand Freshwater Snail

    PubMed Central

    Takacs-Vesbach, Cristina; King, Kayla; Van Horn, David; Larkin, Katelyn; Neiman, Maurine

    2016-01-01

    Different reproductive strategies and the transition to asexuality can be associated with microbial symbionts. Whether such a link exists within mollusks has never been evaluated. We took the first steps towards addressing this possibility by performing pyrosequencing of bacterial 16S rRNA genes associated with Potamopyrgus antipodarum, a New Zealand freshwater snail. A diverse set of 60 tissue collections from P. antipodarum that were genetically and geographically distinct and either obligately sexual or asexual were included, which allowed us to evaluate whether reproductive mode was associated with a particular bacterial community. 2624 unique operational taxonomic units (OTU, 97% DNA similarity) were detected, which were distributed across ~30 phyla. While alpha diversity metrics varied little among individual samples, significant differences in bacterial community composition and structure were detected between sexual and asexual snails, as well as among snails from different lakes and genetic backgrounds. The mean dissimilarity of the bacterial communities between the sexual and asexual P. antipodarum was 90%, largely driven by the presence of Rickettsiales in sexual snails and Rhodobacter in asexual snails. Our study suggests that there might be a link between reproductive mode and the bacterial microbiome of P. antipodarum, though a causal connection requires additional study. PMID:27563725

  9. Use of ice water and salt treatments to eliminate an exotic snail, red-rim melania Melanoides tuberculatus, from small immersible fisheries equipment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ice water and salt treatments were evaluated for disinfection of fisheries equipment contaminated with a non-indigenous tropical snail, the red-rim melania Melanoides tuberculatus. The snail can displace native snails and can transmit trematodes directly to fishes and indirectly to other animals, i...

  10. Tropomyosin or not tropomyosin, what is the relevant allergen in house dust mite and snail cross allergies?

    PubMed

    Bessot, J C; Metz-Favre, C; Rame, J M; De Blay, F; Pauli, G

    2010-02-01

    Since tropomyosin is cross reactive in many arthropods, it was assumed that this highly conserved protein could be responsible for cross reactions in house dust mite (HDM) allergic patients who experienced adverse reactions after crustacean and mollusc ingestion. Here we report two clinical cases where the role of tropomyosin is a matter of debate. In the first case, the clinical history, as well as the results of in vivo and in vitro investigations, are in favour of a shrimp allergy without any snail allergy in a patient sensitized to HDM. In the second, the clinical history and the cutaneous tests are in favour of an allergy to snails without any allergy to shrimps in a patient suffering from HDM allergies. The clinical presentation is different in shrimp and snail allergies. In shrimp allergy, symptoms are mainly urticaria or angio-oedema. In snail allergies, adverse reactions are especially severe asthma. Shrimp tropomyosin is a dominant allergen in crustaceans whereas has a much less prominent role in HDM sensitization. Cross reactivities between HDM and snails have been confirmed by inhibition experiments. However, tropomyosin appears to be a minor allergen or even is not involved in snail allergy. It is necessary to clarify the allergens shared between HDMI and snails. The effects of HDM immunotherapy in snail allergy are questioned. Knowledge of taxonomy can contribute to more precise evaluation of cross reactivities between crustaceans and molluscs.

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

    PubMed

    Rać, Monika Ewa; Stachowska, Ewa; Machoy, Zygmunt

    2005-01-01

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

  12. Global Assessment of Schistosomiasis Control Over the Past Century Shows Targeting the Snail Intermediate Host Works Best

    PubMed Central

    Sokolow, Susanne H.; Wood, Chelsea L.; Jones, Isabel J.; Lopez, Melina; Lafferty, Kevin D.; Kuris, Armand M.; Rickards, Chloe; De Leo, Giulio A.

    2016-01-01

    Background Despite control efforts, human schistosomiasis remains prevalent throughout Africa, Asia, and South America. The global schistosomiasis burden has changed little since the new anthelmintic drug, praziquantel, promised widespread control. Methodology We evaluated large-scale schistosomiasis control attempts over the past century and across the globe by identifying factors that predict control program success: snail control (e.g., molluscicides or biological control), mass drug administrations (MDA) with praziquantel, or a combined strategy using both. For data, we compiled historical information on control tactics and their quantitative outcomes for all 83 countries and territories in which: (i) schistosomiasis was allegedly endemic during the 20th century, and (ii) schistosomiasis remains endemic, or (iii) schistosomiasis has been "eliminated," or is "no longer endemic," or transmission has been interrupted. Principal Findings Widespread snail control reduced prevalence by 92 ± 5% (N = 19) vs. 37 ± 7% (N = 29) for programs using little or no snail control. In addition, ecological, economic, and political factors contributed to schistosomiasis elimination. For instance, snail control was most common and widespread in wealthier countries and when control began earlier in the 20th century. Conclusions/Significance Snail control has been the most effective way to reduce schistosomiasis prevalence. Despite evidence that snail control leads to long-term disease reduction and elimination, most current schistosomiasis control efforts emphasize MDA using praziquantel over snail control. Combining drug-based control programs with affordable snail control seems the best strategy for eliminating schistosomiasis. PMID:27441556

  13. Survival and growth of freshwater pulmonate and nonpulmonate snails in 28-day exposures to copper, ammonia, and pentachlorophenol

    USGS Publications Warehouse

    Besser, John M.; Dorman, Rebecca A.; Hardesty, Douglas K.; Ingersoll, Christopher G.

    2016-01-01

    We performed toxicity tests with two species of pulmonate snails (Lymnaea stagnalis and Physa gyrina) and four taxa of nonpulmonate snails in the family Hydrobiidae (Pyrgulopsis robusta,Taylorconcha serpenticola, Fluminicola sp., and Fontigens aldrichi). Snails were maintained in static-renewal or recirculating culture systems with adults removed periodically to isolate cohorts of offspring for toxicity testing. This method successfully produced offspring for both species of pulmonate snails and for two hydrobiid species, P. robusta and Fluminicola sp. Toxicity tests were performed for 28 days with copper, ammonia, and pentachlorophenol in hard reconstituted water with endpoints of survival and growth. Tests were started with 1-week-old L. stagnalis, 2-week-old P. gyrina, 5- to 13-week-old P. robusta and Fluminicola sp., and older juveniles and adults of several hydrobiid species. For all three chemicals, chronic toxicity values for pulmonate snails were consistently greater than those for hydrobiid snails, and hydrobiids were among the most sensitive taxa in species sensitivity distributions for all three chemicals. These results suggest that the toxicant sensitivity of nonpulmonate snails in the family Hydrobiidae would not be adequately represented by results of toxicity testing with pulmonate snails.

  14. Survival and Growth of Freshwater Pulmonate and Nonpulmonate Snails in 28-Day Exposures to Copper, Ammonia, and Pentachlorophenol.

    PubMed

    Besser, John M; Dorman, Rebecca A; Hardesty, Douglas L; Ingersoll, Christopher G

    2016-02-01

    We performed toxicity tests with two species of pulmonate snails (Lymnaea stagnalis and Physa gyrina) and four taxa of nonpulmonate snails in the family Hydrobiidae (Pyrgulopsis robusta, Taylorconcha serpenticola, Fluminicola sp., and Fontigens aldrichi). Snails were maintained in static-renewal or recirculating culture systems with adults removed periodically to isolate cohorts of offspring for toxicity testing. This method successfully produced offspring for both species of pulmonate snails and for two hydrobiid species, P. robusta and Fluminicola sp. Toxicity tests were performed for 28 days with copper, ammonia, and pentachlorophenol in hard reconstituted water with endpoints of survival and growth. Tests were started with 1-week-old L. stagnalis, 2-week-old P. gyrina, 5- to 13-week-old P. robusta and Fluminicola sp., and older juveniles and adults of several hydrobiid species. For all three chemicals, chronic toxicity values for pulmonate snails were consistently greater than those for hydrobiid snails, and hydrobiids were among the most sensitive taxa in species sensitivity distributions for all three chemicals. These results suggest that the toxicant sensitivity of nonpulmonate snails in the family Hydrobiidae would not be adequately represented by results of toxicity testing with pulmonate snails.

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

    PubMed

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

    2013-10-01

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

  16. Tristetraprolin suppresses the EMT through the down-regulation of Twist1 and Snail1 in cancer cells.

    PubMed

    Yoon, Nal Ae; Jo, Hyun Gun; Lee, Unn Hwa; Park, Ji Hye; Yoon, Ji Eun; Ryu, Jinhyun; Kang, Sang Soo; Min, Young Joo; Ju, Seong-A; Seo, Eun Hui; Huh, In Young; Lee, Byung Ju; Park, Jeong Woo; Cho, Wha Ja

    2016-02-23

    Inhibition of epithelial-mesenchymal transition (EMT)-inducing transcription factors Twist and Snail prevents tumor metastasis but enhances metastatic growth. Here, we report an unexpected role of a tumor suppressor tristetraprolin (TTP) in inhibiting Twist and Snail without enhancing cellular proliferation. TTP bound to the AU-rich element (ARE) within the mRNA 3'UTRs of Twist1 and Snail1, enhanced the decay of their mRNAs and inhibited the EMT of cancer cells. The ectopic expression of Twist1 or Snail1 without their 3'UTRs blocked the inhibitory effects of TTP on the EMT. We also observed that TTP overexpression suppressed the growth of cancer cells. Our data propose a new model whereby TTP down-regulates Twist1 and Snail1 and inhibits both the EMT and the proliferation of cancer cells.

  17. The environmental effects of trace elements concentration in sea snails using atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    El-Amri, F. A.

    2003-05-01

    Water pollution bas increased in heavy industrialised areas. Most industrial water wastes end up in the sea. Monitoring the elemental composition in marine organisms, such as snails, provides the essential elements in living organisms and through the food chain to man. 50 samples of each of two kinds of snails have been collected from the west coast of Libya. Samples were digeste with nitric acid and the concentration of Copper, Iron, Magnesium and Zinc were determined by atomic absorption spectrometry. The results shows that Mg has the highest value while the Copper has the lowest in both kind of snaiis. A pattern of the trace elements concentration was investigated regarding the size and kind of snails.

  18. Growing snails used as sentinels to evaluate terrestrial environment contamination by trace elements.

    PubMed

    Gomot de Vaufleury, A; Pihan, F

    2000-02-01

    Young garden snails (Helix aspersa) reared in standard conditions (aged two months, mean weight 4.6 +/- 0.5 g) set as sentinels in cages laid on the soil for four weeks, give data for biomonitoring the environmental impact of chemicals on soil ecosystems in the field. The survival and the growth of the snails are influenced by the nature of the biotope and the level of the pollutants. Assay of cadmium, copper, lead and zinc bioaccumulated in the tissues of the sentinel snails provides information on the bioavailability of metals in the environment. The encagement model, little used for terrestrial species, can be useful in monitoring (specific and global endpoints) metal pollution of the environment in reference to the trophic level of the primary consumers. Active biomonitoring is positively compared with the passive biomonitoring.

  19. Preference versus performance: body temperature of the intertidal snail Chlorostoma funebralis.

    PubMed

    Tepler, Sarah; Mach, Katharine; Denny, Mark

    2011-04-01

    Evolutionary theory predicts that, in variable environments, it is advantageous for ectothermic organisms to prefer a body temperature slightly below the physiological optimum. This theory works well for many terrestrial organisms but has not been tested for animals inhabiting the hypervariable physical environ